Prometheus monitoring for GitLab Pages

This starts of the prometheus monitoring for GitLab Pages, and
resolves #42

Point to check:
- Are the metric names good, keeping Prometheus' conventions in mind?
- Golang, general style etc
- Shouldn't I do some voodoo magic to import this in the library?

Godeps/Godeps.json

 {
 	"ImportPath": "gitlab.com/gitlab-org/gitlab-pages",
-	"GoVersion": "go1.5",
+	"GoVersion": "go1.7",
+	"GodepVersion": "v77",
 	"Packages": [
 		"./..."
 	],
 	"Deps": [
+		{
+			"ImportPath": "github.com/beorn7/perks/quantile",
+			"Rev": "4c0e84591b9aa9e6dcfdf3e020114cd81f89d5f9"
+		},
+		{
+			"ImportPath": "github.com/golang/protobuf/proto",
+			"Rev": "f592bd283e9ef86337a432eb50e592278c3d534d"
+		},
 		{
 			"ImportPath": "github.com/kardianos/osext",
 			"Rev": "efacde03154693404c65e7aa7d461ac9014acd0c"
 		},
+		{
+			"ImportPath": "github.com/matttproud/golang_protobuf_extensions/pbutil",
+			"Comment": "v1.0.0-2-gc12348c",
+			"Rev": "c12348ce28de40eed0136aa2b644d0ee0650e56c"
+		},
+		{
+			"ImportPath": "github.com/prometheus/client_golang/prometheus",
+			"Comment": "v0.8.0-9-g334af01",
+			"Rev": "334af0119a8f8fb6af5bb950d535c482cac7f836"
+		},
+		{
+			"ImportPath": "github.com/prometheus/client_golang/prometheus/promhttp",
+			"Comment": "v0.8.0-9-g334af01",
+			"Rev": "334af0119a8f8fb6af5bb950d535c482cac7f836"
+		},
+		{
+			"ImportPath": "github.com/prometheus/client_model/go",
+			"Comment": "model-0.0.2-12-gfa8ad6f",
+			"Rev": "fa8ad6fec33561be4280a8f0514318c79d7f6cb6"
+		},
+		{
+			"ImportPath": "github.com/prometheus/common/expfmt",
+			"Rev": "ebdfc6da46522d58825777cf1f90490a5b1ef1d8"
+		},
+		{
+			"ImportPath": "github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg",
+			"Rev": "ebdfc6da46522d58825777cf1f90490a5b1ef1d8"
+		},
+		{
+			"ImportPath": "github.com/prometheus/common/model",
+			"Rev": "ebdfc6da46522d58825777cf1f90490a5b1ef1d8"
+		},
+		{
+			"ImportPath": "github.com/prometheus/procfs",
+			"Rev": "abf152e5f3e97f2fafac028d2cc06c1feb87ffa5"
+		},
 		{
 			"ImportPath": "github.com/stretchr/testify/assert",
 			"Rev": "1297dc01ed0a819ff634c89707081a4df43baf6b"
@@ -18,12 +63,16 @@
 			"Rev": "1297dc01ed0a819ff634c89707081a4df43baf6b"
 		},
 		{
-			"ImportPath": "golang.org/x/crypto/ssh/terminal",
-			"Rev": "1351f936d976c60a0a48d728281922cf63eafb8d"
+			"ImportPath": "golang.org/x/net/http2",
+			"Rev": "07b51741c1d6423d4a6abab1c49940ec09cb1aaf"
+		},
+		{
+			"ImportPath": "golang.org/x/net/http2/hpack",
+			"Rev": "07b51741c1d6423d4a6abab1c49940ec09cb1aaf"
 		},
 		{
-			"ImportPath": "golang.org/x/net/http2",
-			"Rev": "b4e17d61b15679caf2335da776c614169a1b4643"
+			"ImportPath": "golang.org/x/net/lex/httplex",
+			"Rev": "07b51741c1d6423d4a6abab1c49940ec09cb1aaf"
 		}
 	]
 }

README.md

@@ -13,7 +13,7 @@ In large environment it can be time consuming to list all directories, and CNAME
 4. Periodically (every second) it checks the `pages-root/.update` file and reads its content to verify if there was update.
 To force route refresh, reload of configs fill the `pages-root/.update` with random content.
-The reload will be done asynchronously, and it will not interrupt the current requests. 
+The reload will be done asynchronously, and it will not interrupt the current requests.
 ### How it serves content

acceptance_test.go

@@ -2,9 +2,13 @@ package main
 import (
 	"flag"
-	"github.com/stretchr/testify/assert"
+	"fmt"
+	"io/ioutil"
 	"net/http"
+	"regexp"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 var shouldRun = flag.Bool("run-acceptance-tests", false, "Run the acceptance tests?")
@@ -33,7 +37,7 @@ func skipUnlessEnabled(t *testing.T) {
 func TestUnknownHostReturnsNotFound(t *testing.T) {
 	skipUnlessEnabled(t)
-	teardown := RunPagesProcess(t, *pagesBinary, listeners)
+	teardown := RunPagesProcess(t, *pagesBinary, listeners, "")
 	defer teardown()
 	for _, spec := range listeners {
@@ -48,7 +52,7 @@ func TestUnknownHostReturnsNotFound(t *testing.T) {
 func TestKnownHostReturns200(t *testing.T) {
 	skipUnlessEnabled(t)
-	teardown := RunPagesProcess(t, *pagesBinary, listeners)
+	teardown := RunPagesProcess(t, *pagesBinary, listeners, "")
 	defer teardown()
 	for _, spec := range listeners {
@@ -60,3 +64,20 @@ func TestKnownHostReturns200(t *testing.T) {
 		}
 	}
 }
+
+func TestPrometheusMetricsCanBeScraped(t *testing.T) {
+	skipUnlessEnabled(t)
+	listener := []ListenSpec{{"http", "127.0.0.1", "37003"}}
+	fmt.Println("Start pages process")
+	teardown := RunPagesProcess(t, *pagesBinary, listener, ":42345")
+	defer teardown()
+
+	resp, err := http.Get("http://localhost:42345/metrics")
+
+	if assert.NoError(t, err) {
+		defer resp.Body.Close()
+		body, _ := ioutil.ReadAll(resp.Body)
+
+		assert.Regexp(t, regexp.MustCompile("gitlab_pages_http_sessions_active 0"), string(body))
+	}
+}

app.go

@@ -4,9 +4,12 @@ import (
 	"crypto/tls"
 	"log"
 	"net/http"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
+
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 const xForwardedProto = "X-Forwarded-Proto"
@@ -43,6 +46,9 @@ func (a *theApp) serveContent(ww http.ResponseWriter, r *http.Request, https boo
 	w := newLoggingResponseWriter(ww)
 	defer w.Log(r)
+	sessionsActive.Inc()
+	defer sessionsActive.Dec()
+
 	// Add auto redirect
 	if https && !a.RedirectHTTP {
 		u := *r.URL
@@ -62,6 +68,7 @@ func (a *theApp) serveContent(ww http.ResponseWriter, r *http.Request, https boo
 	// Serve static file
 	domain.ServeHTTP(&w, r)
+	processedRequests.WithLabelValues(strconv.Itoa(w.status), r.Method).Inc()
 }
 func (a *theApp) ServeHTTP(ww http.ResponseWriter, r *http.Request) {
@@ -121,6 +128,14 @@ func (a *theApp) Run() {
 		}(fd)
 	}
+	// Serve metrics for Prometheus
+	if a.MetricsAddress != "" {
+		go func() {
+			http.Handle("/metrics", promhttp.Handler())
+			log.Fatal(http.ListenAndServe(a.MetricsAddress, nil))
+		}()
+	}
+
 	go watchDomains(a.Domain, a.UpdateDomains, time.Second)
 	wg.Wait()

app_config.go

@@ -6,9 +6,10 @@ type appConfig struct {
 	RootCertificate []byte
 	RootKey         []byte
-	ListenHTTP  []uintptr
-	ListenHTTPS []uintptr
-	ListenProxy []uintptr
+	ListenHTTP     []uintptr
+	ListenHTTPS    []uintptr
+	ListenProxy    []uintptr
+	MetricsAddress string
 	HTTP2        bool
 	RedirectHTTP bool

domains.go

@@ -30,6 +30,8 @@ func (d domains) addDomain(rootDomain, group, project string, config *domainConf
 	}
 	domainName = strings.ToLower(domainName)
 	d[domainName] = newDomain
+
+	domainsServed.Inc()
 	return nil
 }
@@ -147,6 +149,12 @@ func watchDomains(rootDomain string, updater domainsUpdater, interval time.Durat
 		if updater != nil {
 			updater(domains)
 		}
+
+		// Update prometheus metrics
+		domainLastUpdateTime.Set(float64(time.Now().UTC().Unix()))
+		domainsServed.Set(float64(len(domains)))
+		domainUpdates.Inc()
+
 		time.Sleep(interval)
 	}
 }

helpers_test.go

@@ -124,7 +124,7 @@ func (l ListenSpec) JoinHostPort() string {
 // GetPageFromProcess to do a HTTP GET against a listener.
 //
 // If run as root via sudo, the gitlab-pages process will drop privileges
-func RunPagesProcess(t *testing.T, pagesPath string, listeners []ListenSpec) (teardown func()) {
+func RunPagesProcess(t *testing.T, pagesPath string, listeners []ListenSpec, promPort string) (teardown func()) {
 	var tempfiles []string
 	var args []string
 	var hasHTTPS bool
@@ -146,14 +146,18 @@ func RunPagesProcess(t *testing.T, pagesPath string, listeners []ListenSpec) (te
 		args = append(args, "-root-key", key, "-root-cert", cert)
 	}
+	if promPort != "" {
+		args = append(args, "-metrics-address", promPort)
+	}
+
 	if os.Geteuid() == 0 && os.Getenv("SUDO_UID") != "" && os.Getenv("SUDO_GID") != "" {
 		t.Log("Pages process will drop privileges")
 		args = append(args, "-daemon-uid", os.Getenv("SUDO_UID"), "-daemon-gid", os.Getenv("SUDO_GID"))
 	}
 	cmd := exec.Command(pagesPath, args...)
-	t.Logf("Running %s %v", pagesPath, args)
 	cmd.Start()
+	fmt.Println("Running %s %v", pagesPath, args)
 	// Wait for all TCP servers to be open. Even with this, gitlab-pages
 	// will sometimes return 404 if a HTTP request comes in before it has

main.go

@@ -27,6 +27,7 @@ func appMain() {
 	var useHTTP2 = flag.Bool("use-http2", true, "Enable HTTP2 support")
 	var pagesRoot = flag.String("pages-root", "shared/pages", "The directory where pages are stored")
 	var pagesDomain = flag.String("pages-domain", "gitlab-example.com", "The domain to serve static pages")
+	var metricsAdress = flag.String("metrics-address", "", "The adress to server metrics to")
 	var daemonUID = flag.Uint("daemon-uid", 0, "Drop privileges to this user")
 	var daemonGID = flag.Uint("daemon-gid", 0, "Drop privileges to this group")
@@ -46,6 +47,7 @@ func appMain() {
 	config.Domain = strings.ToLower(*pagesDomain)
 	config.RedirectHTTP = *redirectHTTP
 	config.HTTP2 = *useHTTP2
+	config.MetricsAddress = *metricsAdress
 	if *pagesRootCert != "" {
 		config.RootCertificate = readFile(*pagesRootCert)

metrics.go

+package main
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	domainsServed = prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "gitlab_pages_domains_served_total",
+		Help: "The total number of sites served by this Pages app",
+	})
+
+	domainUpdates = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "gitlab_pages_domains_updated_total",
+		Help: "The total number of site updates processed since daemon start",
+	})
+
+	domainLastUpdateTime = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "gitlab_pages_last_domain_update_seconds",
+		Help: "Seconds since Unix Epoc to the last update for all domains served",
+	})
+
+	processedRequests = prometheus.NewCounterVec(prometheus.CounterOpts{
+		Name: "gitlab_pages_http_requests_total",
+		Help: "Total number of HTTP requests done serving",
+	},
+		[]string{"code", "method"},
+	)
+
+	sessionsActive = prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "gitlab_pages_http_sessions_active",
+		Help: "The number of HTTP requests currently being processed",
+	})
+)
+
+func init() {
+	prometheus.MustRegister(domainsServed)
+	prometheus.MustRegister(domainUpdates)
+	prometheus.MustRegister(domainLastUpdateTime)
+	prometheus.MustRegister(processedRequests)
+	prometheus.MustRegister(sessionsActive)
+}

vendor/github.com/beorn7/perks/LICENSE

+Copyright (C) 2013 Blake Mizerany
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/github.com/beorn7/perks/quantile/exampledata.txt

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vendor/github.com/beorn7/perks/quantile/stream.go

+// Package quantile computes approximate quantiles over an unbounded data
+// stream within low memory and CPU bounds.
+//
+// A small amount of accuracy is traded to achieve the above properties.
+//
+// Multiple streams can be merged before calling Query to generate a single set
+// of results. This is meaningful when the streams represent the same type of
+// data. See Merge and Samples.
+//
+// For more detailed information about the algorithm used, see:
+//
+// Effective Computation of Biased Quantiles over Data Streams
+//
+// http://www.cs.rutgers.edu/~muthu/bquant.pdf
+package quantile
+
+import (
+	"math"
+	"sort"
+)
+
+// Sample holds an observed value and meta information for compression. JSON
+// tags have been added for convenience.
+type Sample struct {
+	Value float64 `json:",string"`
+	Width float64 `json:",string"`
+	Delta float64 `json:",string"`
+}
+
+// Samples represents a slice of samples. It implements sort.Interface.
+type Samples []Sample
+
+func (a Samples) Len() int           { return len(a) }
+func (a Samples) Less(i, j int) bool { return a[i].Value < a[j].Value }
+func (a Samples) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
+
+type invariant func(s *stream, r float64) float64
+
+// NewLowBiased returns an initialized Stream for low-biased quantiles
+// (e.g. 0.01, 0.1, 0.5) where the needed quantiles are not known a priori, but
+// error guarantees can still be given even for the lower ranks of the data
+// distribution.
+//
+// The provided epsilon is a relative error, i.e. the true quantile of a value
+// returned by a query is guaranteed to be within (1±Epsilon)*Quantile.
+//
+// See http://www.cs.rutgers.edu/~muthu/bquant.pdf for time, space, and error
+// properties.
+func NewLowBiased(epsilon float64) *Stream {
+	ƒ := func(s *stream, r float64) float64 {
+		return 2 * epsilon * r
+	}
+	return newStream(ƒ)
+}
+
+// NewHighBiased returns an initialized Stream for high-biased quantiles
+// (e.g. 0.01, 0.1, 0.5) where the needed quantiles are not known a priori, but
+// error guarantees can still be given even for the higher ranks of the data
+// distribution.
+//
+// The provided epsilon is a relative error, i.e. the true quantile of a value
+// returned by a query is guaranteed to be within 1-(1±Epsilon)*(1-Quantile).
+//
+// See http://www.cs.rutgers.edu/~muthu/bquant.pdf for time, space, and error
+// properties.
+func NewHighBiased(epsilon float64) *Stream {
+	ƒ := func(s *stream, r float64) float64 {
+		return 2 * epsilon * (s.n - r)
+	}
+	return newStream(ƒ)
+}
+
+// NewTargeted returns an initialized Stream concerned with a particular set of
+// quantile values that are supplied a priori. Knowing these a priori reduces
+// space and computation time. The targets map maps the desired quantiles to
+// their absolute errors, i.e. the true quantile of a value returned by a query
+// is guaranteed to be within (Quantile±Epsilon).
+//
+// See http://www.cs.rutgers.edu/~muthu/bquant.pdf for time, space, and error properties.
+func NewTargeted(targets map[float64]float64) *Stream {
+	ƒ := func(s *stream, r float64) float64 {
+		var m = math.MaxFloat64
+		var f float64
+		for quantile, epsilon := range targets {
+			if quantile*s.n <= r {
+				f = (2 * epsilon * r) / quantile
+			} else {
+				f = (2 * epsilon * (s.n - r)) / (1 - quantile)
+			}
+			if f < m {
+				m = f
+			}
+		}
+		return m
+	}
+	return newStream(ƒ)
+}
+
+// Stream computes quantiles for a stream of float64s. It is not thread-safe by
+// design. Take care when using across multiple goroutines.
+type Stream struct {
+	*stream
+	b      Samples
+	sorted bool
+}
+
+func newStream(ƒ invariant) *Stream {
+	x := &stream{ƒ: ƒ}
+	return &Stream{x, make(Samples, 0, 500), true}
+}
+
+// Insert inserts v into the stream.
+func (s *Stream) Insert(v float64) {
+	s.insert(Sample{Value: v, Width: 1})
+}
+
+func (s *Stream) insert(sample Sample) {
+	s.b = append(s.b, sample)
+	s.sorted = false
+	if len(s.b) == cap(s.b) {
+		s.flush()
+	}
+}
+
+// Query returns the computed qth percentiles value. If s was created with
+// NewTargeted, and q is not in the set of quantiles provided a priori, Query
+// will return an unspecified result.
+func (s *Stream) Query(q float64) float64 {
+	if !s.flushed() {
+		// Fast path when there hasn't been enough data for a flush;
+		// this also yields better accuracy for small sets of data.
+		l := len(s.b)
+		if l == 0 {
+			return 0
+		}
+		i := int(math.Ceil(float64(l) * q))
+		if i > 0 {
+			i -= 1
+		}
+		s.maybeSort()
+		return s.b[i].Value
+	}
+	s.flush()
+	return s.stream.query(q)
+}
+
+// Merge merges samples into the underlying streams samples. This is handy when
+// merging multiple streams from separate threads, database shards, etc.
+//
+// ATTENTION: This method is broken and does not yield correct results. The
+// underlying algorithm is not capable of merging streams correctly.
+func (s *Stream) Merge(samples Samples) {
+	sort.Sort(samples)
+	s.stream.merge(samples)
+}
+
+// Reset reinitializes and clears the list reusing the samples buffer memory.
+func (s *Stream) Reset() {
+	s.stream.reset()
+	s.b = s.b[:0]
+}
+
+// Samples returns stream samples held by s.
+func (s *Stream) Samples() Samples {
+	if !s.flushed() {
+		return s.b
+	}
+	s.flush()
+	return s.stream.samples()
+}
+
+// Count returns the total number of samples observed in the stream
+// since initialization.
+func (s *Stream) Count() int {
+	return len(s.b) + s.stream.count()
+}
+
+func (s *Stream) flush() {
+	s.maybeSort()
+	s.stream.merge(s.b)
+	s.b = s.b[:0]
+}
+
+func (s *Stream) maybeSort() {
+	if !s.sorted {
+		s.sorted = true
+		sort.Sort(s.b)
+	}
+}
+
+func (s *Stream) flushed() bool {
+	return len(s.stream.l) > 0
+}
+
+type stream struct {
+	n float64
+	l []Sample
+	ƒ invariant
+}
+
+func (s *stream) reset() {
+	s.l = s.l[:0]
+	s.n = 0
+}
+
+func (s *stream) insert(v float64) {
+	s.merge(Samples{{v, 1, 0}})
+}
+
+func (s *stream) merge(samples Samples) {
+	// TODO(beorn7): This tries to merge not only individual samples, but
+	// whole summaries. The paper doesn't mention merging summaries at
+	// all. Unittests show that the merging is inaccurate. Find out how to
+	// do merges properly.
+	var r float64
+	i := 0
+	for _, sample := range samples {
+		for ; i < len(s.l); i++ {
+			c := s.l[i]
+			if c.Value > sample.Value {
+				// Insert at position i.
+				s.l = append(s.l, Sample{})
+				copy(s.l[i+1:], s.l[i:])
+				s.l[i] = Sample{
+					sample.Value,
+					sample.Width,
+					math.Max(sample.Delta, math.Floor(s.ƒ(s, r))-1),
+					// TODO(beorn7): How to calculate delta correctly?
+				}
+				i++
+				goto inserted
+			}
+			r += c.Width
+		}
+		s.l = append(s.l, Sample{sample.Value, sample.Width, 0})
+		i++
+	inserted:
+		s.n += sample.Width
+		r += sample.Width
+	}
+	s.compress()
+}
+
+func (s *stream) count() int {
+	return int(s.n)
+}
+
+func (s *stream) query(q float64) float64 {
+	t := math.Ceil(q * s.n)
+	t += math.Ceil(s.ƒ(s, t) / 2)
+	p := s.l[0]
+	var r float64
+	for _, c := range s.l[1:] {
+		r += p.Width
+		if r+c.Width+c.Delta > t {
+			return p.Value
+		}
+		p = c
+	}
+	return p.Value
+}
+
+func (s *stream) compress() {
+	if len(s.l) < 2 {
+		return
+	}
+	x := s.l[len(s.l)-1]
+	xi := len(s.l) - 1
+	r := s.n - 1 - x.Width
+
+	for i := len(s.l) - 2; i >= 0; i-- {
+		c := s.l[i]
+		if c.Width+x.Width+x.Delta <= s.ƒ(s, r) {
+			x.Width += c.Width
+			s.l[xi] = x
+			// Remove element at i.
+			copy(s.l[i:], s.l[i+1:])
+			s.l = s.l[:len(s.l)-1]
+			xi -= 1
+		} else {
+			x = c
+			xi = i
+		}
+		r -= c.Width
+	}
+}
+
+func (s *stream) samples() Samples {
+	samples := make(Samples, len(s.l))
+	copy(samples, s.l)
+	return samples
+}

vendor/github.com/golang/protobuf/AUTHORS

+# This source code refers to The Go Authors for copyright purposes.
+# The master list of authors is in the main Go distribution,
+# visible at http://tip.golang.org/AUTHORS.

vendor/github.com/golang/protobuf/CONTRIBUTORS

+# This source code was written by the Go contributors.
+# The master list of contributors is in the main Go distribution,
+# visible at http://tip.golang.org/CONTRIBUTORS.

vendor/github.com/golang/protobuf/LICENSE

+Go support for Protocol Buffers - Google's data interchange format
+
+Copyright 2010 The Go Authors.  All rights reserved.
+https://github.com/golang/protobuf
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+    * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+

vendor/github.com/golang/protobuf/proto/Makefile

+# Go support for Protocol Buffers - Google's data interchange format
+#
+# Copyright 2010 The Go Authors.  All rights reserved.
+# https://github.com/golang/protobuf
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+install:
+	go install
+
+test: install generate-test-pbs
+	go test
+
+
+generate-test-pbs:
+	make install
+	make -C testdata
+	protoc --go_out=Mtestdata/test.proto=github.com/golang/protobuf/proto/testdata,Mgoogle/protobuf/any.proto=github.com/golang/protobuf/ptypes/any:. proto3_proto/proto3.proto
+	make

vendor/github.com/golang/protobuf/proto/clone.go

+// Go support for Protocol Buffers - Google's data interchange format
+//
+// Copyright 2011 The Go Authors.  All rights reserved.
+// https://github.com/golang/protobuf
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Protocol buffer deep copy and merge.
+// TODO: RawMessage.
+
+package proto
+
+import (
+	"log"
+	"reflect"
+	"strings"
+)
+
+// Clone returns a deep copy of a protocol buffer.
+func Clone(pb Message) Message {
+	in := reflect.ValueOf(pb)
+	if in.IsNil() {
+		return pb
+	}
+
+	out := reflect.New(in.Type().Elem())
+	// out is empty so a merge is a deep copy.
+	mergeStruct(out.Elem(), in.Elem())
+	return out.Interface().(Message)
+}
+
+// Merge merges src into dst.
+// Required and optional fields that are set in src will be set to that value in dst.
+// Elements of repeated fields will be appended.
+// Merge panics if src and dst are not the same type, or if dst is nil.
+func Merge(dst, src Message) {
+	in := reflect.ValueOf(src)
+	out := reflect.ValueOf(dst)
+	if out.IsNil() {
+		panic("proto: nil destination")
+	}
+	if in.Type() != out.Type() {
+		// Explicit test prior to mergeStruct so that mistyped nils will fail
+		panic("proto: type mismatch")
+	}
+	if in.IsNil() {
+		// Merging nil into non-nil is a quiet no-op
+		return
+	}
+	mergeStruct(out.Elem(), in.Elem())
+}
+
+func mergeStruct(out, in reflect.Value) {
+	sprop := GetProperties(in.Type())
+	for i := 0; i < in.NumField(); i++ {
+		f := in.Type().Field(i)
+		if strings.HasPrefix(f.Name, "XXX_") {
+			continue
+		}
+		mergeAny(out.Field(i), in.Field(i), false, sprop.Prop[i])
+	}
+
+	if emIn, ok := extendable(in.Addr().Interface()); ok {
+		emOut, _ := extendable(out.Addr().Interface())
+		mIn, muIn := emIn.extensionsRead()
+		if mIn != nil {
+			mOut := emOut.extensionsWrite()
+			muIn.Lock()
+			mergeExtension(mOut, mIn)
+			muIn.Unlock()
+		}
+	}
+
+	uf := in.FieldByName("XXX_unrecognized")
+	if !uf.IsValid() {
+		return
+	}
+	uin := uf.Bytes()
+	if len(uin) > 0 {
+		out.FieldByName("XXX_unrecognized").SetBytes(append([]byte(nil), uin...))
+	}
+}
+
+// mergeAny performs a merge between two values of the same type.
+// viaPtr indicates whether the values were indirected through a pointer (implying proto2).
+// prop is set if this is a struct field (it may be nil).
+func mergeAny(out, in reflect.Value, viaPtr bool, prop *Properties) {
+	if in.Type() == protoMessageType {
+		if !in.IsNil() {
+			if out.IsNil() {
+				out.Set(reflect.ValueOf(Clone(in.Interface().(Message))))
+			} else {
+				Merge(out.Interface().(Message), in.Interface().(Message))
+			}
+		}
+		return
+	}
+	switch in.Kind() {
+	case reflect.Bool, reflect.Float32, reflect.Float64, reflect.Int32, reflect.Int64,
+		reflect.String, reflect.Uint32, reflect.Uint64:
+		if !viaPtr && isProto3Zero(in) {
+			return
+		}
+		out.Set(in)
+	case reflect.Interface:
+		// Probably a oneof field; copy non-nil values.
+		if in.IsNil() {
+			return
+		}
+		// Allocate destination if it is not set, or set to a different type.
+		// Otherwise we will merge as normal.
+		if out.IsNil() || out.Elem().Type() != in.Elem().Type() {
+			out.Set(reflect.New(in.Elem().Elem().Type())) // interface -> *T -> T -> new(T)
+		}
+		mergeAny(out.Elem(), in.Elem(), false, nil)
+	case reflect.Map:
+		if in.Len() == 0 {
+			return
+		}
+		if out.IsNil() {
+			out.Set(reflect.MakeMap(in.Type()))
+		}
+		// For maps with value types of *T or []byte we need to deep copy each value.
+		elemKind := in.Type().Elem().Kind()
+		for _, key := range in.MapKeys() {
+			var val reflect.Value
+			switch elemKind {
+			case reflect.Ptr:
+				val = reflect.New(in.Type().Elem().Elem())
+				mergeAny(val, in.MapIndex(key), false, nil)
+			case reflect.Slice:
+				val = in.MapIndex(key)
+				val = reflect.ValueOf(append([]byte{}, val.Bytes()...))
+			default:
+				val = in.MapIndex(key)
+			}
+			out.SetMapIndex(key, val)
+		}
+	case reflect.Ptr:
+		if in.IsNil() {
+			return
+		}
+		if out.IsNil() {
+			out.Set(reflect.New(in.Elem().Type()))
+		}
+		mergeAny(out.Elem(), in.Elem(), true, nil)
+	case reflect.Slice:
+		if in.IsNil() {
+			return
+		}
+		if in.Type().Elem().Kind() == reflect.Uint8 {
+			// []byte is a scalar bytes field, not a repeated field.
+
+			// Edge case: if this is in a proto3 message, a zero length
+			// bytes field is considered the zero value, and should not
+			// be merged.
+			if prop != nil && prop.proto3 && in.Len() == 0 {
+				return
+			}
+
+			// Make a deep copy.
+			// Append to []byte{} instead of []byte(nil) so that we never end up
+			// with a nil result.
+			out.SetBytes(append([]byte{}, in.Bytes()...))
+			return
+		}
+		n := in.Len()
+		if out.IsNil() {
+			out.Set(reflect.MakeSlice(in.Type(), 0, n))
+		}
+		switch in.Type().Elem().Kind() {
+		case reflect.Bool, reflect.Float32, reflect.Float64, reflect.Int32, reflect.Int64,
+			reflect.String, reflect.Uint32, reflect.Uint64:
+			out.Set(reflect.AppendSlice(out, in))
+		default:
+			for i := 0; i < n; i++ {
+				x := reflect.Indirect(reflect.New(in.Type().Elem()))
+				mergeAny(x, in.Index(i), false, nil)
+				out.Set(reflect.Append(out, x))
+			}
+		}
+	case reflect.Struct:
+		mergeStruct(out, in)
+	default:
+		// unknown type, so not a protocol buffer
+		log.Printf("proto: don't know how to copy %v", in)
+	}
+}
+
+func mergeExtension(out, in map[int32]Extension) {
+	for extNum, eIn := range in {
+		eOut := Extension{desc: eIn.desc}
+		if eIn.value != nil {
+			v := reflect.New(reflect.TypeOf(eIn.value)).Elem()
+			mergeAny(v, reflect.ValueOf(eIn.value), false, nil)
+			eOut.value = v.Interface()
+		}
+		if eIn.enc != nil {
+			eOut.enc = make([]byte, len(eIn.enc))
+			copy(eOut.enc, eIn.enc)
+		}
+
+		out[extNum] = eOut
+	}
+}

vendor/github.com/golang/protobuf/proto/decode.go

+// Go support for Protocol Buffers - Google's data interchange format
+//
+// Copyright 2010 The Go Authors.  All rights reserved.
+// https://github.com/golang/protobuf
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package proto
+
+/*
+ * Routines for decoding protocol buffer data to construct in-memory representations.
+ */
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"reflect"
+)
+
+// errOverflow is returned when an integer is too large to be represented.
+var errOverflow = errors.New("proto: integer overflow")
+
+// ErrInternalBadWireType is returned by generated code when an incorrect
+// wire type is encountered. It does not get returned to user code.
+var ErrInternalBadWireType = errors.New("proto: internal error: bad wiretype for oneof")
+
+// The fundamental decoders that interpret bytes on the wire.
+// Those that take integer types all return uint64 and are
+// therefore of type valueDecoder.
+
+// DecodeVarint reads a varint-encoded integer from the slice.
+// It returns the integer and the number of bytes consumed, or
+// zero if there is not enough.
+// This is the format for the
+// int32, int64, uint32, uint64, bool, and enum
+// protocol buffer types.
+func DecodeVarint(buf []byte) (x uint64, n int) {
+	// x, n already 0
+	for shift := uint(0); shift < 64; shift += 7 {
+		if n >= len(buf) {
+			return 0, 0
+		}
+		b := uint64(buf[n])
+		n++
+		x |= (b & 0x7F) << shift
+		if (b & 0x80) == 0 {
+			return x, n
+		}
+	}
+
+	// The number is too large to represent in a 64-bit value.
+	return 0, 0
+}
+
+// DecodeVarint reads a varint-encoded integer from the Buffer.
+// This is the format for the
+// int32, int64, uint32, uint64, bool, and enum
+// protocol buffer types.
+func (p *Buffer) DecodeVarint() (x uint64, err error) {
+	// x, err already 0
+
+	i := p.index
+	l := len(p.buf)
+
+	for shift := uint(0); shift < 64; shift += 7 {
+		if i >= l {
+			err = io.ErrUnexpectedEOF
+			return
+		}
+		b := p.buf[i]
+		i++
+		x |= (uint64(b) & 0x7F) << shift
+		if b < 0x80 {
+			p.index = i
+			return
+		}
+	}
+
+	// The number is too large to represent in a 64-bit value.
+	err = errOverflow
+	return
+}
+
+// DecodeFixed64 reads a 64-bit integer from the Buffer.
+// This is the format for the
+// fixed64, sfixed64, and double protocol buffer types.
+func (p *Buffer) DecodeFixed64() (x uint64, err error) {
+	// x, err already 0
+	i := p.index + 8
+	if i < 0 || i > len(p.buf) {
+		err = io.ErrUnexpectedEOF
+		return
+	}
+	p.index = i
+
+	x = uint64(p.buf[i-8])
+	x |= uint64(p.buf[i-7]) << 8
+	x |= uint64(p.buf[i-6]) << 16
+	x |= uint64(p.buf[i-5]) << 24
+	x |= uint64(p.buf[i-4]) << 32
+	x |= uint64(p.buf[i-3]) << 40
+	x |= uint64(p.buf[i-2]) << 48
+	x |= uint64(p.buf[i-1]) << 56
+	return
+}
+
+// DecodeFixed32 reads a 32-bit integer from the Buffer.
+// This is the format for the
+// fixed32, sfixed32, and float protocol buffer types.
+func (p *Buffer) DecodeFixed32() (x uint64, err error) {
+	// x, err already 0
+	i := p.index + 4
+	if i < 0 || i > len(p.buf) {
+		err = io.ErrUnexpectedEOF
+		return
+	}
+	p.index = i
+
+	x = uint64(p.buf[i-4])
+	x |= uint64(p.buf[i-3]) << 8
+	x |= uint64(p.buf[i-2]) << 16
+	x |= uint64(p.buf[i-1]) << 24
+	return
+}
+
+// DecodeZigzag64 reads a zigzag-encoded 64-bit integer
+// from the Buffer.
+// This is the format used for the sint64 protocol buffer type.
+func (p *Buffer) DecodeZigzag64() (x uint64, err error) {
+	x, err = p.DecodeVarint()
+	if err != nil {
+		return
+	}
+	x = (x >> 1) ^ uint64((int64(x&1)<<63)>>63)
+	return
+}
+
+// DecodeZigzag32 reads a zigzag-encoded 32-bit integer
+// from  the Buffer.
+// This is the format used for the sint32 protocol buffer type.
+func (p *Buffer) DecodeZigzag32() (x uint64, err error) {
+	x, err = p.DecodeVarint()
+	if err != nil {
+		return
+	}
+	x = uint64((uint32(x) >> 1) ^ uint32((int32(x&1)<<31)>>31))
+	return
+}
+
+// These are not ValueDecoders: they produce an array of bytes or a string.
+// bytes, embedded messages
+
+// DecodeRawBytes reads a count-delimited byte buffer from the Buffer.
+// This is the format used for the bytes protocol buffer
+// type and for embedded messages.
+func (p *Buffer) DecodeRawBytes(alloc bool) (buf []byte, err error) {
+	n, err := p.DecodeVarint()
+	if err != nil {
+		return nil, err
+	}
+
+	nb := int(n)
+	if nb < 0 {
+		return nil, fmt.Errorf("proto: bad byte length %d", nb)
+	}
+	end := p.index + nb
+	if end < p.index || end > len(p.buf) {
+		return nil, io.ErrUnexpectedEOF
+	}
+
+	if !alloc {
+		// todo: check if can get more uses of alloc=false
+		buf = p.buf[p.index:end]
+		p.index += nb
+		return
+	}
+
+	buf = make([]byte, nb)
+	copy(buf, p.buf[p.index:])
+	p.index += nb
+	return
+}
+
+// DecodeStringBytes reads an encoded string from the Buffer.
+// This is the format used for the proto2 string type.
+func (p *Buffer) DecodeStringBytes() (s string, err error) {
+	buf, err := p.DecodeRawBytes(false)
+	if err != nil {
+		return
+	}
+	return string(buf), nil
+}
+
+// Skip the next item in the buffer. Its wire type is decoded and presented as an argument.
+// If the protocol buffer has extensions, and the field matches, add it as an extension.
+// Otherwise, if the XXX_unrecognized field exists, append the skipped data there.
+func (o *Buffer) skipAndSave(t reflect.Type, tag, wire int, base structPointer, unrecField field) error {
+	oi := o.index
+
+	err := o.skip(t, tag, wire)
+	if err != nil {
+		return err
+	}
+
+	if !unrecField.IsValid() {
+		return nil
+	}
+
+	ptr := structPointer_Bytes(base, unrecField)
+
+	// Add the skipped field to struct field
+	obuf := o.buf
+
+	o.buf = *ptr
+	o.EncodeVarint(uint64(tag<<3 | wire))
+	*ptr = append(o.buf, obuf[oi:o.index]...)
+
+	o.buf = obuf
+
+	return nil
+}
+
+// Skip the next item in the buffer. Its wire type is decoded and presented as an argument.
+func (o *Buffer) skip(t reflect.Type, tag, wire int) error {
+
+	var u uint64
+	var err error
+
+	switch wire {
+	case WireVarint:
+		_, err = o.DecodeVarint()
+	case WireFixed64:
+		_, err = o.DecodeFixed64()
+	case WireBytes:
+		_, err = o.DecodeRawBytes(false)
+	case WireFixed32:
+		_, err = o.DecodeFixed32()
+	case WireStartGroup:
+		for {
+			u, err = o.DecodeVarint()
+			if err != nil {
+				break
+			}
+			fwire := int(u & 0x7)
+			if fwire == WireEndGroup {
+				break
+			}
+			ftag := int(u >> 3)
+			err = o.skip(t, ftag, fwire)
+			if err != nil {
+				break
+			}
+		}
+	default:
+		err = fmt.Errorf("proto: can't skip unknown wire type %d for %s", wire, t)
+	}
+	return err
+}
+
+// Unmarshaler is the interface representing objects that can
+// unmarshal themselves.  The method should reset the receiver before
+// decoding starts.  The argument points to data that may be
+// overwritten, so implementations should not keep references to the
+// buffer.
+type Unmarshaler interface {
+	Unmarshal([]byte) error
+}
+
+// Unmarshal parses the protocol buffer representation in buf and places the
+// decoded result in pb.  If the struct underlying pb does not match
+// the data in buf, the results can be unpredictable.
+//
+// Unmarshal resets pb before starting to unmarshal, so any
+// existing data in pb is always removed. Use UnmarshalMerge
+// to preserve and append to existing data.
+func Unmarshal(buf []byte, pb Message) error {
+	pb.Reset()
+	return UnmarshalMerge(buf, pb)
+}
+
+// UnmarshalMerge parses the protocol buffer representation in buf and
+// writes the decoded result to pb.  If the struct underlying pb does not match
+// the data in buf, the results can be unpredictable.
+//
+// UnmarshalMerge merges into existing data in pb.
+// Most code should use Unmarshal instead.
+func UnmarshalMerge(buf []byte, pb Message) error {
+	// If the object can unmarshal itself, let it.
+	if u, ok := pb.(Unmarshaler); ok {
+		return u.Unmarshal(buf)
+	}
+	return NewBuffer(buf).Unmarshal(pb)
+}
+
+// DecodeMessage reads a count-delimited message from the Buffer.
+func (p *Buffer) DecodeMessage(pb Message) error {
+	enc, err := p.DecodeRawBytes(false)
+	if err != nil {
+		return err
+	}
+	return NewBuffer(enc).Unmarshal(pb)
+}
+
+// DecodeGroup reads a tag-delimited group from the Buffer.
+func (p *Buffer) DecodeGroup(pb Message) error {
+	typ, base, err := getbase(pb)
+	if err != nil {
+		return err
+	}
+	return p.unmarshalType(typ.Elem(), GetProperties(typ.Elem()), true, base)
+}
+
+// Unmarshal parses the protocol buffer representation in the
+// Buffer and places the decoded result in pb.  If the struct
+// underlying pb does not match the data in the buffer, the results can be
+// unpredictable.
+func (p *Buffer) Unmarshal(pb Message) error {
+	// If the object can unmarshal itself, let it.
+	if u, ok := pb.(Unmarshaler); ok {
+		err := u.Unmarshal(p.buf[p.index:])
+		p.index = len(p.buf)
+		return err
+	}
+
+	typ, base, err := getbase(pb)
+	if err != nil {
+		return err
+	}
+
+	err = p.unmarshalType(typ.Elem(), GetProperties(typ.Elem()), false, base)
+
+	if collectStats {
+		stats.Decode++
+	}
+
+	return err
+}
+
+// unmarshalType does the work of unmarshaling a structure.
+func (o *Buffer) unmarshalType(st reflect.Type, prop *StructProperties, is_group bool, base structPointer) error {
+	var state errorState
+	required, reqFields := prop.reqCount, uint64(0)
+
+	var err error
+	for err == nil && o.index < len(o.buf) {
+		oi := o.index
+		var u uint64
+		u, err = o.DecodeVarint()
+		if err != nil {
+			break
+		}
+		wire := int(u & 0x7)
+		if wire == WireEndGroup {
+			if is_group {
+				if required > 0 {
+					// Not enough information to determine the exact field.
+					// (See below.)
+					return &RequiredNotSetError{"{Unknown}"}
+				}
+				return nil // input is satisfied
+			}
+			return fmt.Errorf("proto: %s: wiretype end group for non-group", st)
+		}
+		tag := int(u >> 3)
+		if tag <= 0 {
+			return fmt.Errorf("proto: %s: illegal tag %d (wire type %d)", st, tag, wire)
+		}
+		fieldnum, ok := prop.decoderTags.get(tag)
+		if !ok {
+			// Maybe it's an extension?
+			if prop.extendable {
+				if e, _ := extendable(structPointer_Interface(base, st)); isExtensionField(e, int32(tag)) {
+					if err = o.skip(st, tag, wire); err == nil {
+						extmap := e.extensionsWrite()
+						ext := extmap[int32(tag)] // may be missing
+						ext.enc = append(ext.enc, o.buf[oi:o.index]...)
+						extmap[int32(tag)] = ext
+					}
+					continue
+				}
+			}
+			// Maybe it's a oneof?
+			if prop.oneofUnmarshaler != nil {
+				m := structPointer_Interface(base, st).(Message)
+				// First return value indicates whether tag is a oneof field.
+				ok, err = prop.oneofUnmarshaler(m, tag, wire, o)
+				if err == ErrInternalBadWireType {
+					// Map the error to something more descriptive.
+					// Do the formatting here to save generated code space.
+					err = fmt.Errorf("bad wiretype for oneof field in %T", m)
+				}
+				if ok {
+					continue
+				}
+			}
+			err = o.skipAndSave(st, tag, wire, base, prop.unrecField)
+			continue
+		}
+		p := prop.Prop[fieldnum]
+
+		if p.dec == nil {
+			fmt.Fprintf(os.Stderr, "proto: no protobuf decoder for %s.%s\n", st, st.Field(fieldnum).Name)
+			continue
+		}
+		dec := p.dec
+		if wire != WireStartGroup && wire != p.WireType {
+			if wire == WireBytes && p.packedDec != nil {
+				// a packable field
+				dec = p.packedDec
+			} else {
+				err = fmt.Errorf("proto: bad wiretype for field %s.%s: got wiretype %d, want %d", st, st.Field(fieldnum).Name, wire, p.WireType)
+				continue
+			}
+		}
+		decErr := dec(o, p, base)
+		if decErr != nil && !state.shouldContinue(decErr, p) {
+			err = decErr
+		}
+		if err == nil && p.Required {
+			// Successfully decoded a required field.
+			if tag <= 64 {
+				// use bitmap for fields 1-64 to catch field reuse.
+				var mask uint64 = 1 << uint64(tag-1)
+				if reqFields&mask == 0 {
+					// new required field
+					reqFields |= mask
+					required--
+				}
+			} else {
+				// This is imprecise. It can be fooled by a required field
+				// with a tag > 64 that is encoded twice; that's very rare.
+				// A fully correct implementation would require allocating
+				// a data structure, which we would like to avoid.
+				required--
+			}
+		}
+	}
+	if err == nil {
+		if is_group {
+			return io.ErrUnexpectedEOF
+		}
+		if state.err != nil {
+			return state.err
+		}
+		if required > 0 {
+			// Not enough information to determine the exact field. If we use extra
+			// CPU, we could determine the field only if the missing required field
+			// has a tag <= 64 and we check reqFields.
+			return &RequiredNotSetError{"{Unknown}"}
+		}
+	}
+	return err
+}
+
+// Individual type decoders
+// For each,
+//	u is the decoded value,
+//	v is a pointer to the field (pointer) in the struct
+
+// Sizes of the pools to allocate inside the Buffer.
+// The goal is modest amortization and allocation
+// on at least 16-byte boundaries.
+const (
+	boolPoolSize   = 16
+	uint32PoolSize = 8
+	uint64PoolSize = 4
+)
+
+// Decode a bool.
+func (o *Buffer) dec_bool(p *Properties, base structPointer) error {
+	u, err := p.valDec(o)
+	if err != nil {
+		return err
+	}
+	if len(o.bools) == 0 {
+		o.bools = make([]bool, boolPoolSize)
+	}
+	o.bools[0] = u != 0
+	*structPointer_Bool(base, p.field) = &o.bools[0]
+	o.bools = o.bools[1:]
+	return nil
+}
+
+func (o *Buffer) dec_proto3_bool(p *Properties, base structPointer) error {
+	u, err := p.valDec(o)
+	if err != nil {
+		return err
+	}
+	*structPointer_BoolVal(base, p.field) = u != 0
+	return nil
+}
+
+// Decode an int32.
+func (o *Buffer) dec_int32(p *Properties, base structPointer) error {
+	u, err := p.valDec(o)
+	if err != nil {
+		return err
+	}
+	word32_Set(structPointer_Word32(base, p.field), o, uint32(u))
+	return nil
+}
+
+func (o *Buffer) dec_proto3_int32(p *Properties, base structPointer) error {
+	u, err := p.valDec(o)
+	if err != nil {
+		return err
+	}
+	word32Val_Set(structPointer_Word32Val(base, p.field), uint32(u))
+	return nil
+}
+
+// Decode an int64.
+func (o *Buffer) dec_int64(p *Properties, base structPointer) error {
+	u, err := p.valDec(o)
+	if err != nil {
+		return err
+	}
+	word64_Set(structPointer_Word64(base, p.field), o, u)
+	return nil
+}
+
+func (o *Buffer) dec_proto3_int64(p *Properties, base structPointer) error {
+	u, err := p.valDec(o)
+	if err != nil {
+		return err
+	}
+	word64Val_Set(structPointer_Word64Val(base, p.field), o, u)
+	return nil
+}
+
+// Decode a string.
+func (o *Buffer) dec_string(p *Properties, base structPointer) error {
+	s, err := o.DecodeStringBytes()
+	if err != nil {
+		return err
+	}
+	*structPointer_String(base, p.field) = &s
+	return nil
+}
+
+func (o *Buffer) dec_proto3_string(p *Properties, base structPointer) error {
+	s, err := o.DecodeStringBytes()
+	if err != nil {
+		return err
+	}
+	*structPointer_StringVal(base, p.field) = s
+	return nil
+}
+
+// Decode a slice of bytes ([]byte).
+func (o *Buffer) dec_slice_byte(p *Properties, base structPointer) error {
+	b, err := o.DecodeRawBytes(true)
+	if err != nil {
+		return err
+	}
+	*structPointer_Bytes(base, p.field) = b
+	return nil
+}
+
+// Decode a slice of bools ([]bool).
+func (o *Buffer) dec_slice_bool(p *Properties, base structPointer) error {
+	u, err := p.valDec(o)
+	if err != nil {
+		return err
+	}
+	v := structPointer_BoolSlice(base, p.field)
+	*v = append(*v, u != 0)
+	return nil
+}
+
+// Decode a slice of bools ([]bool) in packed format.
+func (o *Buffer) dec_slice_packed_bool(p *Properties, base structPointer) error {
+	v := structPointer_BoolSlice(base, p.field)
+
+	nn, err := o.DecodeVarint()
+	if err != nil {
+		return err
+	}
+	nb := int(nn) // number of bytes of encoded bools
+	fin := o.index + nb
+	if fin < o.index {
+		return errOverflow
+	}
+
+	y := *v
+	for o.index < fin {
+		u, err := p.valDec(o)
+		if err != nil {
+			return err
+		}
+		y = append(y, u != 0)
+	}
+
+	*v = y
+	return nil
+}
+
+// Decode a slice of int32s ([]int32).
+func (o *Buffer) dec_slice_int32(p *Properties, base structPointer) error {
+	u, err := p.valDec(o)
+	if err != nil {
+		return err
+	}
+	structPointer_Word32Slice(base, p.field).Append(uint32(u))
+	return nil
+}
+
+// Decode a slice of int32s ([]int32) in packed format.
+func (o *Buffer) dec_slice_packed_int32(p *Properties, base structPointer) error {
+	v := structPointer_Word32Slice(base, p.field)
+
+	nn, err := o.DecodeVarint()
+	if err != nil {
+		return err
+	}
+	nb := int(nn) // number of bytes of encoded int32s
+
+	fin := o.index + nb
+	if fin < o.index {
+		return errOverflow
+	}
+	for o.index < fin {
+		u, err := p.valDec(o)
+		if err != nil {
+			return err
+		}
+		v.Append(uint32(u))
+	}
+	return nil
+}
+
+// Decode a slice of int64s ([]int64).
+func (o *Buffer) dec_slice_int64(p *Properties, base structPointer) error {
+	u, err := p.valDec(o)
+	if err != nil {
+		return err
+	}
+
+	structPointer_Word64Slice(base, p.field).Append(u)
+	return nil
+}
+
+// Decode a slice of int64s ([]int64) in packed format.
+func (o *Buffer) dec_slice_packed_int64(p *Properties, base structPointer) error {
+	v := structPointer_Word64Slice(base, p.field)
+
+	nn, err := o.DecodeVarint()
+	if err != nil {
+		return err
+	}
+	nb := int(nn) // number of bytes of encoded int64s
+
+	fin := o.index + nb
+	if fin < o.index {
+		return errOverflow
+	}
+	for o.index < fin {
+		u, err := p.valDec(o)
+		if err != nil {
+			return err
+		}
+		v.Append(u)
+	}
+	return nil
+}
+
+// Decode a slice of strings ([]string).
+func (o *Buffer) dec_slice_string(p *Properties, base structPointer) error {
+	s, err := o.DecodeStringBytes()
+	if err != nil {
+		return err
+	}
+	v := structPointer_StringSlice(base, p.field)
+	*v = append(*v, s)
+	return nil
+}
+
+// Decode a slice of slice of bytes ([][]byte).
+func (o *Buffer) dec_slice_slice_byte(p *Properties, base structPointer) error {
+	b, err := o.DecodeRawBytes(true)
+	if err != nil {
+		return err
+	}
+	v := structPointer_BytesSlice(base, p.field)
+	*v = append(*v, b)
+	return nil
+}
+
+// Decode a map field.
+func (o *Buffer) dec_new_map(p *Properties, base structPointer) error {
+	raw, err := o.DecodeRawBytes(false)
+	if err != nil {
+		return err
+	}
+	oi := o.index       // index at the end of this map entry
+	o.index -= len(raw) // move buffer back to start of map entry
+
+	mptr := structPointer_NewAt(base, p.field, p.mtype) // *map[K]V
+	if mptr.Elem().IsNil() {
+		mptr.Elem().Set(reflect.MakeMap(mptr.Type().Elem()))
+	}
+	v := mptr.Elem() // map[K]V
+
+	// Prepare addressable doubly-indirect placeholders for the key and value types.
+	// See enc_new_map for why.
+	keyptr := reflect.New(reflect.PtrTo(p.mtype.Key())).Elem() // addressable *K
+	keybase := toStructPointer(keyptr.Addr())                  // **K
+
+	var valbase structPointer
+	var valptr reflect.Value
+	switch p.mtype.Elem().Kind() {
+	case reflect.Slice:
+		// []byte
+		var dummy []byte
+		valptr = reflect.ValueOf(&dummy)  // *[]byte
+		valbase = toStructPointer(valptr) // *[]byte
+	case reflect.Ptr:
+		// message; valptr is **Msg; need to allocate the intermediate pointer
+		valptr = reflect.New(reflect.PtrTo(p.mtype.Elem())).Elem() // addressable *V
+		valptr.Set(reflect.New(valptr.Type().Elem()))
+		valbase = toStructPointer(valptr)
+	default:
+		// everything else
+		valptr = reflect.New(reflect.PtrTo(p.mtype.Elem())).Elem() // addressable *V
+		valbase = toStructPointer(valptr.Addr())                   // **V
+	}
+
+	// Decode.
+	// This parses a restricted wire format, namely the encoding of a message
+	// with two fields. See enc_new_map for the format.
+	for o.index < oi {
+		// tagcode for key and value properties are always a single byte
+		// because they have tags 1 and 2.
+		tagcode := o.buf[o.index]
+		o.index++
+		switch tagcode {
+		case p.mkeyprop.tagcode[0]:
+			if err := p.mkeyprop.dec(o, p.mkeyprop, keybase); err != nil {
+				return err
+			}
+		case p.mvalprop.tagcode[0]:
+			if err := p.mvalprop.dec(o, p.mvalprop, valbase); err != nil {
+				return err
+			}
+		default:
+			// TODO: Should we silently skip this instead?
+			return fmt.Errorf("proto: bad map data tag %d", raw[0])
+		}
+	}
+	keyelem, valelem := keyptr.Elem(), valptr.Elem()
+	if !keyelem.IsValid() {
+		keyelem = reflect.Zero(p.mtype.Key())
+	}
+	if !valelem.IsValid() {
+		valelem = reflect.Zero(p.mtype.Elem())
+	}
+
+	v.SetMapIndex(keyelem, valelem)
+	return nil
+}
+
+// Decode a group.
+func (o *Buffer) dec_struct_group(p *Properties, base structPointer) error {
+	bas := structPointer_GetStructPointer(base, p.field)
+	if structPointer_IsNil(bas) {
+		// allocate new nested message
+		bas = toStructPointer(reflect.New(p.stype))
+		structPointer_SetStructPointer(base, p.field, bas)
+	}
+	return o.unmarshalType(p.stype, p.sprop, true, bas)
+}
+
+// Decode an embedded message.
+func (o *Buffer) dec_struct_message(p *Properties, base structPointer) (err error) {
+	raw, e := o.DecodeRawBytes(false)
+	if e != nil {
+		return e
+	}
+
+	bas := structPointer_GetStructPointer(base, p.field)
+	if structPointer_IsNil(bas) {
+		// allocate new nested message
+		bas = toStructPointer(reflect.New(p.stype))
+		structPointer_SetStructPointer(base, p.field, bas)
+	}
+
+	// If the object can unmarshal itself, let it.
+	if p.isUnmarshaler {
+		iv := structPointer_Interface(bas, p.stype)
+		return iv.(Unmarshaler).Unmarshal(raw)
+	}
+
+	obuf := o.buf
+	oi := o.index
+	o.buf = raw
+	o.index = 0
+
+	err = o.unmarshalType(p.stype, p.sprop, false, bas)
+	o.buf = obuf
+	o.index = oi
+
+	return err
+}
+
+// Decode a slice of embedded messages.
+func (o *Buffer) dec_slice_struct_message(p *Properties, base structPointer) error {
+	return o.dec_slice_struct(p, false, base)
+}
+
+// Decode a slice of embedded groups.
+func (o *Buffer) dec_slice_struct_group(p *Properties, base structPointer) error {
+	return o.dec_slice_struct(p, true, base)
+}
+
+// Decode a slice of structs ([]*struct).
+func (o *Buffer) dec_slice_struct(p *Properties, is_group bool, base structPointer) error {
+	v := reflect.New(p.stype)
+	bas := toStructPointer(v)
+	structPointer_StructPointerSlice(base, p.field).Append(bas)
+
+	if is_group {
+		err := o.unmarshalType(p.stype, p.sprop, is_group, bas)
+		return err
+	}
+
+	raw, err := o.DecodeRawBytes(false)
+	if err != nil {
+		return err
+	}
+
+	// If the object can unmarshal itself, let it.
+	if p.isUnmarshaler {
+		iv := v.Interface()
+		return iv.(Unmarshaler).Unmarshal(raw)
+	}
+
+	obuf := o.buf
+	oi := o.index
+	o.buf = raw
+	o.index = 0
+
+	err = o.unmarshalType(p.stype, p.sprop, is_group, bas)
+
+	o.buf = obuf
+	o.index = oi
+
+	return err
+}

vendor/github.com/golang/protobuf/proto/encode.go

+// Go support for Protocol Buffers - Google's data interchange format
+//
+// Copyright 2010 The Go Authors.  All rights reserved.
+// https://github.com/golang/protobuf
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package proto
+
+/*
+ * Routines for encoding data into the wire format for protocol buffers.
+ */
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"sort"
+)
+
+// RequiredNotSetError is the error returned if Marshal is called with
+// a protocol buffer struct whose required fields have not
+// all been initialized. It is also the error returned if Unmarshal is
+// called with an encoded protocol buffer that does not include all the
+// required fields.
+//
+// When printed, RequiredNotSetError reports the first unset required field in a
+// message. If the field cannot be precisely determined, it is reported as
+// "{Unknown}".
+type RequiredNotSetError struct {
+	field string
+}
+
+func (e *RequiredNotSetError) Error() string {
+	return fmt.Sprintf("proto: required field %q not set", e.field)
+}
+
+var (
+	// errRepeatedHasNil is the error returned if Marshal is called with
+	// a struct with a repeated field containing a nil element.
+	errRepeatedHasNil = errors.New("proto: repeated field has nil element")
+
+	// errOneofHasNil is the error returned if Marshal is called with
+	// a struct with a oneof field containing a nil element.
+	errOneofHasNil = errors.New("proto: oneof field has nil value")
+
+	// ErrNil is the error returned if Marshal is called with nil.
+	ErrNil = errors.New("proto: Marshal called with nil")
+
+	// ErrTooLarge is the error returned if Marshal is called with a
+	// message that encodes to >2GB.
+	ErrTooLarge = errors.New("proto: message encodes to over 2 GB")
+)
+
+// The fundamental encoders that put bytes on the wire.
+// Those that take integer types all accept uint64 and are
+// therefore of type valueEncoder.
+
+const maxVarintBytes = 10 // maximum length of a varint
+
+// maxMarshalSize is the largest allowed size of an encoded protobuf,
+// since C++ and Java use signed int32s for the size.
+const maxMarshalSize = 1<<31 - 1
+
+// EncodeVarint returns the varint encoding of x.
+// This is the format for the
+// int32, int64, uint32, uint64, bool, and enum
+// protocol buffer types.
+// Not used by the package itself, but helpful to clients
+// wishing to use the same encoding.
+func EncodeVarint(x uint64) []byte {
+	var buf [maxVarintBytes]byte
+	var n int
+	for n = 0; x > 127; n++ {
+		buf[n] = 0x80 | uint8(x&0x7F)
+		x >>= 7
+	}
+	buf[n] = uint8(x)
+	n++
+	return buf[0:n]
+}
+
+// EncodeVarint writes a varint-encoded integer to the Buffer.
+// This is the format for the
+// int32, int64, uint32, uint64, bool, and enum
+// protocol buffer types.
+func (p *Buffer) EncodeVarint(x uint64) error {
+	for x >= 1<<7 {
+		p.buf = append(p.buf, uint8(x&0x7f|0x80))
+		x >>= 7
+	}
+	p.buf = append(p.buf, uint8(x))
+	return nil
+}
+
+// SizeVarint returns the varint encoding size of an integer.
+func SizeVarint(x uint64) int {
+	return sizeVarint(x)
+}
+
+func sizeVarint(x uint64) (n int) {
+	for {
+		n++
+		x >>= 7
+		if x == 0 {
+			break
+		}
+	}
+	return n
+}
+
+// EncodeFixed64 writes a 64-bit integer to the Buffer.
+// This is the format for the
+// fixed64, sfixed64, and double protocol buffer types.
+func (p *Buffer) EncodeFixed64(x uint64) error {
+	p.buf = append(p.buf,
+		uint8(x),
+		uint8(x>>8),
+		uint8(x>>16),
+		uint8(x>>24),
+		uint8(x>>32),
+		uint8(x>>40),
+		uint8(x>>48),
+		uint8(x>>56))
+	return nil
+}
+
+func sizeFixed64(x uint64) int {
+	return 8
+}
+
+// EncodeFixed32 writes a 32-bit integer to the Buffer.
+// This is the format for the
+// fixed32, sfixed32, and float protocol buffer types.
+func (p *Buffer) EncodeFixed32(x uint64) error {
+	p.buf = append(p.buf,
+		uint8(x),
+		uint8(x>>8),
+		uint8(x>>16),
+		uint8(x>>24))
+	return nil
+}
+
+func sizeFixed32(x uint64) int {
+	return 4
+}
+
+// EncodeZigzag64 writes a zigzag-encoded 64-bit integer
+// to the Buffer.
+// This is the format used for the sint64 protocol buffer type.
+func (p *Buffer) EncodeZigzag64(x uint64) error {
+	// use signed number to get arithmetic right shift.
+	return p.EncodeVarint(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+
+func sizeZigzag64(x uint64) int {
+	return sizeVarint(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+
+// EncodeZigzag32 writes a zigzag-encoded 32-bit integer
+// to the Buffer.
+// This is the format used for the sint32 protocol buffer type.
+func (p *Buffer) EncodeZigzag32(x uint64) error {
+	// use signed number to get arithmetic right shift.
+	return p.EncodeVarint(uint64((uint32(x) << 1) ^ uint32((int32(x) >> 31))))
+}
+
+func sizeZigzag32(x uint64) int {
+	return sizeVarint(uint64((uint32(x) << 1) ^ uint32((int32(x) >> 31))))
+}
+
+// EncodeRawBytes writes a count-delimited byte buffer to the Buffer.
+// This is the format used for the bytes protocol buffer
+// type and for embedded messages.
+func (p *Buffer) EncodeRawBytes(b []byte) error {
+	p.EncodeVarint(uint64(len(b)))
+	p.buf = append(p.buf, b...)
+	return nil
+}
+
+func sizeRawBytes(b []byte) int {
+	return sizeVarint(uint64(len(b))) +
+		len(b)
+}
+
+// EncodeStringBytes writes an encoded string to the Buffer.
+// This is the format used for the proto2 string type.
+func (p *Buffer) EncodeStringBytes(s string) error {
+	p.EncodeVarint(uint64(len(s)))
+	p.buf = append(p.buf, s...)
+	return nil
+}
+
+func sizeStringBytes(s string) int {
+	return sizeVarint(uint64(len(s))) +
+		len(s)
+}
+
+// Marshaler is the interface representing objects that can marshal themselves.
+type Marshaler interface {
+	Marshal() ([]byte, error)
+}
+
+// Marshal takes the protocol buffer
+// and encodes it into the wire format, returning the data.
+func Marshal(pb Message) ([]byte, error) {
+	// Can the object marshal itself?
+	if m, ok := pb.(Marshaler); ok {
+		return m.Marshal()
+	}
+	p := NewBuffer(nil)
+	err := p.Marshal(pb)
+	var state errorState
+	if err != nil && !state.shouldContinue(err, nil) {
+		return nil, err
+	}
+	if p.buf == nil && err == nil {
+		// Return a non-nil slice on success.
+		return []byte{}, nil
+	}
+	return p.buf, err
+}
+
+// EncodeMessage writes the protocol buffer to the Buffer,
+// prefixed by a varint-encoded length.
+func (p *Buffer) EncodeMessage(pb Message) error {
+	t, base, err := getbase(pb)
+	if structPointer_IsNil(base) {
+		return ErrNil
+	}
+	if err == nil {
+		var state errorState
+		err = p.enc_len_struct(GetProperties(t.Elem()), base, &state)
+	}
+	return err
+}
+
+// Marshal takes the protocol buffer
+// and encodes it into the wire format, writing the result to the
+// Buffer.
+func (p *Buffer) Marshal(pb Message) error {
+	// Can the object marshal itself?
+	if m, ok := pb.(Marshaler); ok {
+		data, err := m.Marshal()
+		if err != nil {
+			return err
+		}
+		p.buf = append(p.buf, data...)
+		return nil
+	}
+
+	t, base, err := getbase(pb)
+	if structPointer_IsNil(base) {
+		return ErrNil
+	}
+	if err == nil {
+		err = p.enc_struct(GetProperties(t.Elem()), base)
+	}
+
+	if collectStats {
+		stats.Encode++
+	}
+
+	if len(p.buf) > maxMarshalSize {
+		return ErrTooLarge
+	}
+	return err
+}
+
+// Size returns the encoded size of a protocol buffer.
+func Size(pb Message) (n int) {
+	// Can the object marshal itself?  If so, Size is slow.
+	// TODO: add Size to Marshaler, or add a Sizer interface.
+	if m, ok := pb.(Marshaler); ok {
+		b, _ := m.Marshal()
+		return len(b)
+	}
+
+	t, base, err := getbase(pb)
+	if structPointer_IsNil(base) {
+		return 0
+	}
+	if err == nil {
+		n = size_struct(GetProperties(t.Elem()), base)
+	}
+
+	if collectStats {
+		stats.Size++
+	}
+
+	return
+}
+
+// Individual type encoders.
+
+// Encode a bool.
+func (o *Buffer) enc_bool(p *Properties, base structPointer) error {
+	v := *structPointer_Bool(base, p.field)
+	if v == nil {
+		return ErrNil
+	}
+	x := 0
+	if *v {
+		x = 1
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	p.valEnc(o, uint64(x))
+	return nil
+}
+
+func (o *Buffer) enc_proto3_bool(p *Properties, base structPointer) error {
+	v := *structPointer_BoolVal(base, p.field)
+	if !v {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	p.valEnc(o, 1)
+	return nil
+}
+
+func size_bool(p *Properties, base structPointer) int {
+	v := *structPointer_Bool(base, p.field)
+	if v == nil {
+		return 0
+	}
+	return len(p.tagcode) + 1 // each bool takes exactly one byte
+}
+
+func size_proto3_bool(p *Properties, base structPointer) int {
+	v := *structPointer_BoolVal(base, p.field)
+	if !v && !p.oneof {
+		return 0
+	}
+	return len(p.tagcode) + 1 // each bool takes exactly one byte
+}
+
+// Encode an int32.
+func (o *Buffer) enc_int32(p *Properties, base structPointer) error {
+	v := structPointer_Word32(base, p.field)
+	if word32_IsNil(v) {
+		return ErrNil
+	}
+	x := int32(word32_Get(v)) // permit sign extension to use full 64-bit range
+	o.buf = append(o.buf, p.tagcode...)
+	p.valEnc(o, uint64(x))
+	return nil
+}
+
+func (o *Buffer) enc_proto3_int32(p *Properties, base structPointer) error {
+	v := structPointer_Word32Val(base, p.field)
+	x := int32(word32Val_Get(v)) // permit sign extension to use full 64-bit range
+	if x == 0 {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	p.valEnc(o, uint64(x))
+	return nil
+}
+
+func size_int32(p *Properties, base structPointer) (n int) {
+	v := structPointer_Word32(base, p.field)
+	if word32_IsNil(v) {
+		return 0
+	}
+	x := int32(word32_Get(v)) // permit sign extension to use full 64-bit range
+	n += len(p.tagcode)
+	n += p.valSize(uint64(x))
+	return
+}
+
+func size_proto3_int32(p *Properties, base structPointer) (n int) {
+	v := structPointer_Word32Val(base, p.field)
+	x := int32(word32Val_Get(v)) // permit sign extension to use full 64-bit range
+	if x == 0 && !p.oneof {
+		return 0
+	}
+	n += len(p.tagcode)
+	n += p.valSize(uint64(x))
+	return
+}
+
+// Encode a uint32.
+// Exactly the same as int32, except for no sign extension.
+func (o *Buffer) enc_uint32(p *Properties, base structPointer) error {
+	v := structPointer_Word32(base, p.field)
+	if word32_IsNil(v) {
+		return ErrNil
+	}
+	x := word32_Get(v)
+	o.buf = append(o.buf, p.tagcode...)
+	p.valEnc(o, uint64(x))
+	return nil
+}
+
+func (o *Buffer) enc_proto3_uint32(p *Properties, base structPointer) error {
+	v := structPointer_Word32Val(base, p.field)
+	x := word32Val_Get(v)
+	if x == 0 {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	p.valEnc(o, uint64(x))
+	return nil
+}
+
+func size_uint32(p *Properties, base structPointer) (n int) {
+	v := structPointer_Word32(base, p.field)
+	if word32_IsNil(v) {
+		return 0
+	}
+	x := word32_Get(v)
+	n += len(p.tagcode)
+	n += p.valSize(uint64(x))
+	return
+}
+
+func size_proto3_uint32(p *Properties, base structPointer) (n int) {
+	v := structPointer_Word32Val(base, p.field)
+	x := word32Val_Get(v)
+	if x == 0 && !p.oneof {
+		return 0
+	}
+	n += len(p.tagcode)
+	n += p.valSize(uint64(x))
+	return
+}
+
+// Encode an int64.
+func (o *Buffer) enc_int64(p *Properties, base structPointer) error {
+	v := structPointer_Word64(base, p.field)
+	if word64_IsNil(v) {
+		return ErrNil
+	}
+	x := word64_Get(v)
+	o.buf = append(o.buf, p.tagcode...)
+	p.valEnc(o, x)
+	return nil
+}
+
+func (o *Buffer) enc_proto3_int64(p *Properties, base structPointer) error {
+	v := structPointer_Word64Val(base, p.field)
+	x := word64Val_Get(v)
+	if x == 0 {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	p.valEnc(o, x)
+	return nil
+}
+
+func size_int64(p *Properties, base structPointer) (n int) {
+	v := structPointer_Word64(base, p.field)
+	if word64_IsNil(v) {
+		return 0
+	}
+	x := word64_Get(v)
+	n += len(p.tagcode)
+	n += p.valSize(x)
+	return
+}
+
+func size_proto3_int64(p *Properties, base structPointer) (n int) {
+	v := structPointer_Word64Val(base, p.field)
+	x := word64Val_Get(v)
+	if x == 0 && !p.oneof {
+		return 0
+	}
+	n += len(p.tagcode)
+	n += p.valSize(x)
+	return
+}
+
+// Encode a string.
+func (o *Buffer) enc_string(p *Properties, base structPointer) error {
+	v := *structPointer_String(base, p.field)
+	if v == nil {
+		return ErrNil
+	}
+	x := *v
+	o.buf = append(o.buf, p.tagcode...)
+	o.EncodeStringBytes(x)
+	return nil
+}
+
+func (o *Buffer) enc_proto3_string(p *Properties, base structPointer) error {
+	v := *structPointer_StringVal(base, p.field)
+	if v == "" {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	o.EncodeStringBytes(v)
+	return nil
+}
+
+func size_string(p *Properties, base structPointer) (n int) {
+	v := *structPointer_String(base, p.field)
+	if v == nil {
+		return 0
+	}
+	x := *v
+	n += len(p.tagcode)
+	n += sizeStringBytes(x)
+	return
+}
+
+func size_proto3_string(p *Properties, base structPointer) (n int) {
+	v := *structPointer_StringVal(base, p.field)
+	if v == "" && !p.oneof {
+		return 0
+	}
+	n += len(p.tagcode)
+	n += sizeStringBytes(v)
+	return
+}
+
+// All protocol buffer fields are nillable, but be careful.
+func isNil(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice:
+		return v.IsNil()
+	}
+	return false
+}
+
+// Encode a message struct.
+func (o *Buffer) enc_struct_message(p *Properties, base structPointer) error {
+	var state errorState
+	structp := structPointer_GetStructPointer(base, p.field)
+	if structPointer_IsNil(structp) {
+		return ErrNil
+	}
+
+	// Can the object marshal itself?
+	if p.isMarshaler {
+		m := structPointer_Interface(structp, p.stype).(Marshaler)
+		data, err := m.Marshal()
+		if err != nil && !state.shouldContinue(err, nil) {
+			return err
+		}
+		o.buf = append(o.buf, p.tagcode...)
+		o.EncodeRawBytes(data)
+		return state.err
+	}
+
+	o.buf = append(o.buf, p.tagcode...)
+	return o.enc_len_struct(p.sprop, structp, &state)
+}
+
+func size_struct_message(p *Properties, base structPointer) int {
+	structp := structPointer_GetStructPointer(base, p.field)
+	if structPointer_IsNil(structp) {
+		return 0
+	}
+
+	// Can the object marshal itself?
+	if p.isMarshaler {
+		m := structPointer_Interface(structp, p.stype).(Marshaler)
+		data, _ := m.Marshal()
+		n0 := len(p.tagcode)
+		n1 := sizeRawBytes(data)
+		return n0 + n1
+	}
+
+	n0 := len(p.tagcode)
+	n1 := size_struct(p.sprop, structp)
+	n2 := sizeVarint(uint64(n1)) // size of encoded length
+	return n0 + n1 + n2
+}
+
+// Encode a group struct.
+func (o *Buffer) enc_struct_group(p *Properties, base structPointer) error {
+	var state errorState
+	b := structPointer_GetStructPointer(base, p.field)
+	if structPointer_IsNil(b) {
+		return ErrNil
+	}
+
+	o.EncodeVarint(uint64((p.Tag << 3) | WireStartGroup))
+	err := o.enc_struct(p.sprop, b)
+	if err != nil && !state.shouldContinue(err, nil) {
+		return err
+	}
+	o.EncodeVarint(uint64((p.Tag << 3) | WireEndGroup))
+	return state.err
+}
+
+func size_struct_group(p *Properties, base structPointer) (n int) {
+	b := structPointer_GetStructPointer(base, p.field)
+	if structPointer_IsNil(b) {
+		return 0
+	}
+
+	n += sizeVarint(uint64((p.Tag << 3) | WireStartGroup))
+	n += size_struct(p.sprop, b)
+	n += sizeVarint(uint64((p.Tag << 3) | WireEndGroup))
+	return
+}
+
+// Encode a slice of bools ([]bool).
+func (o *Buffer) enc_slice_bool(p *Properties, base structPointer) error {
+	s := *structPointer_BoolSlice(base, p.field)
+	l := len(s)
+	if l == 0 {
+		return ErrNil
+	}
+	for _, x := range s {
+		o.buf = append(o.buf, p.tagcode...)
+		v := uint64(0)
+		if x {
+			v = 1
+		}
+		p.valEnc(o, v)
+	}
+	return nil
+}
+
+func size_slice_bool(p *Properties, base structPointer) int {
+	s := *structPointer_BoolSlice(base, p.field)
+	l := len(s)
+	if l == 0 {
+		return 0
+	}
+	return l * (len(p.tagcode) + 1) // each bool takes exactly one byte
+}
+
+// Encode a slice of bools ([]bool) in packed format.
+func (o *Buffer) enc_slice_packed_bool(p *Properties, base structPointer) error {
+	s := *structPointer_BoolSlice(base, p.field)
+	l := len(s)
+	if l == 0 {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	o.EncodeVarint(uint64(l)) // each bool takes exactly one byte
+	for _, x := range s {
+		v := uint64(0)
+		if x {
+			v = 1
+		}
+		p.valEnc(o, v)
+	}
+	return nil
+}
+
+func size_slice_packed_bool(p *Properties, base structPointer) (n int) {
+	s := *structPointer_BoolSlice(base, p.field)
+	l := len(s)
+	if l == 0 {
+		return 0
+	}
+	n += len(p.tagcode)
+	n += sizeVarint(uint64(l))
+	n += l // each bool takes exactly one byte
+	return
+}
+
+// Encode a slice of bytes ([]byte).
+func (o *Buffer) enc_slice_byte(p *Properties, base structPointer) error {
+	s := *structPointer_Bytes(base, p.field)
+	if s == nil {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	o.EncodeRawBytes(s)
+	return nil
+}
+
+func (o *Buffer) enc_proto3_slice_byte(p *Properties, base structPointer) error {
+	s := *structPointer_Bytes(base, p.field)
+	if len(s) == 0 {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	o.EncodeRawBytes(s)
+	return nil
+}
+
+func size_slice_byte(p *Properties, base structPointer) (n int) {
+	s := *structPointer_Bytes(base, p.field)
+	if s == nil && !p.oneof {
+		return 0
+	}
+	n += len(p.tagcode)
+	n += sizeRawBytes(s)
+	return
+}
+
+func size_proto3_slice_byte(p *Properties, base structPointer) (n int) {
+	s := *structPointer_Bytes(base, p.field)
+	if len(s) == 0 && !p.oneof {
+		return 0
+	}
+	n += len(p.tagcode)
+	n += sizeRawBytes(s)
+	return
+}
+
+// Encode a slice of int32s ([]int32).
+func (o *Buffer) enc_slice_int32(p *Properties, base structPointer) error {
+	s := structPointer_Word32Slice(base, p.field)
+	l := s.Len()
+	if l == 0 {
+		return ErrNil
+	}
+	for i := 0; i < l; i++ {
+		o.buf = append(o.buf, p.tagcode...)
+		x := int32(s.Index(i)) // permit sign extension to use full 64-bit range
+		p.valEnc(o, uint64(x))
+	}
+	return nil
+}
+
+func size_slice_int32(p *Properties, base structPointer) (n int) {
+	s := structPointer_Word32Slice(base, p.field)
+	l := s.Len()
+	if l == 0 {
+		return 0
+	}
+	for i := 0; i < l; i++ {
+		n += len(p.tagcode)
+		x := int32(s.Index(i)) // permit sign extension to use full 64-bit range
+		n += p.valSize(uint64(x))
+	}
+	return
+}
+
+// Encode a slice of int32s ([]int32) in packed format.
+func (o *Buffer) enc_slice_packed_int32(p *Properties, base structPointer) error {
+	s := structPointer_Word32Slice(base, p.field)
+	l := s.Len()
+	if l == 0 {
+		return ErrNil
+	}
+	// TODO: Reuse a Buffer.
+	buf := NewBuffer(nil)
+	for i := 0; i < l; i++ {
+		x := int32(s.Index(i)) // permit sign extension to use full 64-bit range
+		p.valEnc(buf, uint64(x))
+	}
+
+	o.buf = append(o.buf, p.tagcode...)
+	o.EncodeVarint(uint64(len(buf.buf)))
+	o.buf = append(o.buf, buf.buf...)
+	return nil
+}
+
+func size_slice_packed_int32(p *Properties, base structPointer) (n int) {
+	s := structPointer_Word32Slice(base, p.field)
+	l := s.Len()
+	if l == 0 {
+		return 0
+	}
+	var bufSize int
+	for i := 0; i < l; i++ {
+		x := int32(s.Index(i)) // permit sign extension to use full 64-bit range
+		bufSize += p.valSize(uint64(x))
+	}
+
+	n += len(p.tagcode)
+	n += sizeVarint(uint64(bufSize))
+	n += bufSize
+	return
+}
+
+// Encode a slice of uint32s ([]uint32).
+// Exactly the same as int32, except for no sign extension.
+func (o *Buffer) enc_slice_uint32(p *Properties, base structPointer) error {
+	s := structPointer_Word32Slice(base, p.field)
+	l := s.Len()
+	if l == 0 {
+		return ErrNil
+	}
+	for i := 0; i < l; i++ {
+		o.buf = append(o.buf, p.tagcode...)
+		x := s.Index(i)
+		p.valEnc(o, uint64(x))
+	}
+	return nil
+}
+
+func size_slice_uint32(p *Properties, base structPointer) (n int) {
+	s := structPointer_Word32Slice(base, p.field)
+	l := s.Len()
+	if l == 0 {
+		return 0
+	}
+	for i := 0; i < l; i++ {
+		n += len(p.tagcode)
+		x := s.Index(i)
+		n += p.valSize(uint64(x))
+	}
+	return
+}
+
+// Encode a slice of uint32s ([]uint32) in packed format.
+// Exactly the same as int32, except for no sign extension.
+func (o *Buffer) enc_slice_packed_uint32(p *Properties, base structPointer) error {
+	s := structPointer_Word32Slice(base, p.field)
+	l := s.Len()
+	if l == 0 {
+		return ErrNil
+	}
+	// TODO: Reuse a Buffer.
+	buf := NewBuffer(nil)
+	for i := 0; i < l; i++ {
+		p.valEnc(buf, uint64(s.Index(i)))
+	}
+
+	o.buf = append(o.buf, p.tagcode...)
+	o.EncodeVarint(uint64(len(buf.buf)))
+	o.buf = append(o.buf, buf.buf...)
+	return nil
+}
+
+func size_slice_packed_uint32(p *Properties, base structPointer) (n int) {
+	s := structPointer_Word32Slice(base, p.field)
+	l := s.Len()
+	if l == 0 {
+		return 0
+	}
+	var bufSize int
+	for i := 0; i < l; i++ {
+		bufSize += p.valSize(uint64(s.Index(i)))
+	}
+
+	n += len(p.tagcode)
+	n += sizeVarint(uint64(bufSize))
+	n += bufSize
+	return
+}
+
+// Encode a slice of int64s ([]int64).
+func (o *Buffer) enc_slice_int64(p *Properties, base structPointer) error {
+	s := structPointer_Word64Slice(base, p.field)
+	l := s.Len()
+	if l == 0 {
+		return ErrNil
+	}
+	for i := 0; i < l; i++ {
+		o.buf = append(o.buf, p.tagcode...)
+		p.valEnc(o, s.Index(i))
+	}
+	return nil
+}
+
+func size_slice_int64(p *Properties, base structPointer) (n int) {
+	s := structPointer_Word64Slice(base, p.field)
+	l := s.Len()
+	if l == 0 {
+		return 0
+	}
+	for i := 0; i < l; i++ {
+		n += len(p.tagcode)
+		n += p.valSize(s.Index(i))
+	}
+	return
+}
+
+// Encode a slice of int64s ([]int64) in packed format.
+func (o *Buffer) enc_slice_packed_int64(p *Properties, base structPointer) error {
+	s := structPointer_Word64Slice(base, p.field)
+	l := s.Len()
+	if l == 0 {
+		return ErrNil
+	}
+	// TODO: Reuse a Buffer.
+	buf := NewBuffer(nil)
+	for i := 0; i < l; i++ {
+		p.valEnc(buf, s.Index(i))
+	}
+
+	o.buf = append(o.buf, p.tagcode...)
+	o.EncodeVarint(uint64(len(buf.buf)))
+	o.buf = append(o.buf, buf.buf...)
+	return nil
+}
+
+func size_slice_packed_int64(p *Properties, base structPointer) (n int) {
+	s := structPointer_Word64Slice(base, p.field)
+	l := s.Len()
+	if l == 0 {
+		return 0
+	}
+	var bufSize int
+	for i := 0; i < l; i++ {
+		bufSize += p.valSize(s.Index(i))
+	}
+
+	n += len(p.tagcode)
+	n += sizeVarint(uint64(bufSize))
+	n += bufSize
+	return
+}
+
+// Encode a slice of slice of bytes ([][]byte).
+func (o *Buffer) enc_slice_slice_byte(p *Properties, base structPointer) error {
+	ss := *structPointer_BytesSlice(base, p.field)
+	l := len(ss)
+	if l == 0 {
+		return ErrNil
+	}
+	for i := 0; i < l; i++ {
+		o.buf = append(o.buf, p.tagcode...)
+		o.EncodeRawBytes(ss[i])
+	}
+	return nil
+}
+
+func size_slice_slice_byte(p *Properties, base structPointer) (n int) {
+	ss := *structPointer_BytesSlice(base, p.field)
+	l := len(ss)
+	if l == 0 {
+		return 0
+	}
+	n += l * len(p.tagcode)
+	for i := 0; i < l; i++ {
+		n += sizeRawBytes(ss[i])
+	}
+	return
+}
+
+// Encode a slice of strings ([]string).
+func (o *Buffer) enc_slice_string(p *Properties, base structPointer) error {
+	ss := *structPointer_StringSlice(base, p.field)
+	l := len(ss)
+	for i := 0; i < l; i++ {
+		o.buf = append(o.buf, p.tagcode...)
+		o.EncodeStringBytes(ss[i])
+	}
+	return nil
+}
+
+func size_slice_string(p *Properties, base structPointer) (n int) {
+	ss := *structPointer_StringSlice(base, p.field)
+	l := len(ss)
+	n += l * len(p.tagcode)
+	for i := 0; i < l; i++ {
+		n += sizeStringBytes(ss[i])
+	}
+	return
+}
+
+// Encode a slice of message structs ([]*struct).
+func (o *Buffer) enc_slice_struct_message(p *Properties, base structPointer) error {
+	var state errorState
+	s := structPointer_StructPointerSlice(base, p.field)
+	l := s.Len()
+
+	for i := 0; i < l; i++ {
+		structp := s.Index(i)
+		if structPointer_IsNil(structp) {
+			return errRepeatedHasNil
+		}
+
+		// Can the object marshal itself?
+		if p.isMarshaler {
+			m := structPointer_Interface(structp, p.stype).(Marshaler)
+			data, err := m.Marshal()
+			if err != nil && !state.shouldContinue(err, nil) {
+				return err
+			}
+			o.buf = append(o.buf, p.tagcode...)
+			o.EncodeRawBytes(data)
+			continue
+		}
+
+		o.buf = append(o.buf, p.tagcode...)
+		err := o.enc_len_struct(p.sprop, structp, &state)
+		if err != nil && !state.shouldContinue(err, nil) {
+			if err == ErrNil {
+				return errRepeatedHasNil
+			}
+			return err
+		}
+	}
+	return state.err
+}
+
+func size_slice_struct_message(p *Properties, base structPointer) (n int) {
+	s := structPointer_StructPointerSlice(base, p.field)
+	l := s.Len()
+	n += l * len(p.tagcode)
+	for i := 0; i < l; i++ {
+		structp := s.Index(i)
+		if structPointer_IsNil(structp) {
+			return // return the size up to this point
+		}
+
+		// Can the object marshal itself?
+		if p.isMarshaler {
+			m := structPointer_Interface(structp, p.stype).(Marshaler)
+			data, _ := m.Marshal()
+			n += len(p.tagcode)
+			n += sizeRawBytes(data)
+			continue
+		}
+
+		n0 := size_struct(p.sprop, structp)
+		n1 := sizeVarint(uint64(n0)) // size of encoded length
+		n += n0 + n1
+	}
+	return
+}
+
+// Encode a slice of group structs ([]*struct).
+func (o *Buffer) enc_slice_struct_group(p *Properties, base structPointer) error {
+	var state errorState
+	s := structPointer_StructPointerSlice(base, p.field)
+	l := s.Len()
+
+	for i := 0; i < l; i++ {
+		b := s.Index(i)
+		if structPointer_IsNil(b) {
+			return errRepeatedHasNil
+		}
+
+		o.EncodeVarint(uint64((p.Tag << 3) | WireStartGroup))
+
+		err := o.enc_struct(p.sprop, b)
+
+		if err != nil && !state.shouldContinue(err, nil) {
+			if err == ErrNil {
+				return errRepeatedHasNil
+			}
+			return err
+		}
+
+		o.EncodeVarint(uint64((p.Tag << 3) | WireEndGroup))
+	}
+	return state.err
+}
+
+func size_slice_struct_group(p *Properties, base structPointer) (n int) {
+	s := structPointer_StructPointerSlice(base, p.field)
+	l := s.Len()
+
+	n += l * sizeVarint(uint64((p.Tag<<3)|WireStartGroup))
+	n += l * sizeVarint(uint64((p.Tag<<3)|WireEndGroup))
+	for i := 0; i < l; i++ {
+		b := s.Index(i)
+		if structPointer_IsNil(b) {
+			return // return size up to this point
+		}
+
+		n += size_struct(p.sprop, b)
+	}
+	return
+}
+
+// Encode an extension map.
+func (o *Buffer) enc_map(p *Properties, base structPointer) error {
+	exts := structPointer_ExtMap(base, p.field)
+	if err := encodeExtensionsMap(*exts); err != nil {
+		return err
+	}
+
+	return o.enc_map_body(*exts)
+}
+
+func (o *Buffer) enc_exts(p *Properties, base structPointer) error {
+	exts := structPointer_Extensions(base, p.field)
+	if err := encodeExtensions(exts); err != nil {
+		return err
+	}
+	v, _ := exts.extensionsRead()
+
+	return o.enc_map_body(v)
+}
+
+func (o *Buffer) enc_map_body(v map[int32]Extension) error {
+	// Fast-path for common cases: zero or one extensions.
+	if len(v) <= 1 {
+		for _, e := range v {
+			o.buf = append(o.buf, e.enc...)
+		}
+		return nil
+	}
+
+	// Sort keys to provide a deterministic encoding.
+	keys := make([]int, 0, len(v))
+	for k := range v {
+		keys = append(keys, int(k))
+	}
+	sort.Ints(keys)
+
+	for _, k := range keys {
+		o.buf = append(o.buf, v[int32(k)].enc...)
+	}
+	return nil
+}
+
+func size_map(p *Properties, base structPointer) int {
+	v := structPointer_ExtMap(base, p.field)
+	return extensionsMapSize(*v)
+}
+
+func size_exts(p *Properties, base structPointer) int {
+	v := structPointer_Extensions(base, p.field)
+	return extensionsSize(v)
+}
+
+// Encode a map field.
+func (o *Buffer) enc_new_map(p *Properties, base structPointer) error {
+	var state errorState // XXX: or do we need to plumb this through?
+
+	/*
+		A map defined as
+			map<key_type, value_type> map_field = N;
+		is encoded in the same way as
+			message MapFieldEntry {
+				key_type key = 1;
+				value_type value = 2;
+			}
+			repeated MapFieldEntry map_field = N;
+	*/
+
+	v := structPointer_NewAt(base, p.field, p.mtype).Elem() // map[K]V
+	if v.Len() == 0 {
+		return nil
+	}
+
+	keycopy, valcopy, keybase, valbase := mapEncodeScratch(p.mtype)
+
+	enc := func() error {
+		if err := p.mkeyprop.enc(o, p.mkeyprop, keybase); err != nil {
+			return err
+		}
+		if err := p.mvalprop.enc(o, p.mvalprop, valbase); err != nil && err != ErrNil {
+			return err
+		}
+		return nil
+	}
+
+	// Don't sort map keys. It is not required by the spec, and C++ doesn't do it.
+	for _, key := range v.MapKeys() {
+		val := v.MapIndex(key)
+
+		keycopy.Set(key)
+		valcopy.Set(val)
+
+		o.buf = append(o.buf, p.tagcode...)
+		if err := o.enc_len_thing(enc, &state); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func size_new_map(p *Properties, base structPointer) int {
+	v := structPointer_NewAt(base, p.field, p.mtype).Elem() // map[K]V
+
+	keycopy, valcopy, keybase, valbase := mapEncodeScratch(p.mtype)
+
+	n := 0
+	for _, key := range v.MapKeys() {
+		val := v.MapIndex(key)
+		keycopy.Set(key)
+		valcopy.Set(val)
+
+		// Tag codes for key and val are the responsibility of the sub-sizer.
+		keysize := p.mkeyprop.size(p.mkeyprop, keybase)
+		valsize := p.mvalprop.size(p.mvalprop, valbase)
+		entry := keysize + valsize
+		// Add on tag code and length of map entry itself.
+		n += len(p.tagcode) + sizeVarint(uint64(entry)) + entry
+	}
+	return n
+}
+
+// mapEncodeScratch returns a new reflect.Value matching the map's value type,
+// and a structPointer suitable for passing to an encoder or sizer.
+func mapEncodeScratch(mapType reflect.Type) (keycopy, valcopy reflect.Value, keybase, valbase structPointer) {
+	// Prepare addressable doubly-indirect placeholders for the key and value types.
+	// This is needed because the element-type encoders expect **T, but the map iteration produces T.
+
+	keycopy = reflect.New(mapType.Key()).Elem()                 // addressable K
+	keyptr := reflect.New(reflect.PtrTo(keycopy.Type())).Elem() // addressable *K
+	keyptr.Set(keycopy.Addr())                                  //
+	keybase = toStructPointer(keyptr.Addr())                    // **K
+
+	// Value types are more varied and require special handling.
+	switch mapType.Elem().Kind() {
+	case reflect.Slice:
+		// []byte
+		var dummy []byte
+		valcopy = reflect.ValueOf(&dummy).Elem() // addressable []byte
+		valbase = toStructPointer(valcopy.Addr())
+	case reflect.Ptr:
+		// message; the generated field type is map[K]*Msg (so V is *Msg),
+		// so we only need one level of indirection.
+		valcopy = reflect.New(mapType.Elem()).Elem() // addressable V
+		valbase = toStructPointer(valcopy.Addr())
+	default:
+		// everything else
+		valcopy = reflect.New(mapType.Elem()).Elem()                // addressable V
+		valptr := reflect.New(reflect.PtrTo(valcopy.Type())).Elem() // addressable *V
+		valptr.Set(valcopy.Addr())                                  //
+		valbase = toStructPointer(valptr.Addr())                    // **V
+	}
+	return
+}
+
+// Encode a struct.
+func (o *Buffer) enc_struct(prop *StructProperties, base structPointer) error {
+	var state errorState
+	// Encode fields in tag order so that decoders may use optimizations
+	// that depend on the ordering.
+	// https://developers.google.com/protocol-buffers/docs/encoding#order
+	for _, i := range prop.order {
+		p := prop.Prop[i]
+		if p.enc != nil {
+			err := p.enc(o, p, base)
+			if err != nil {
+				if err == ErrNil {
+					if p.Required && state.err == nil {
+						state.err = &RequiredNotSetError{p.Name}
+					}
+				} else if err == errRepeatedHasNil {
+					// Give more context to nil values in repeated fields.
+					return errors.New("repeated field " + p.OrigName + " has nil element")
+				} else if !state.shouldContinue(err, p) {
+					return err
+				}
+			}
+			if len(o.buf) > maxMarshalSize {
+				return ErrTooLarge
+			}
+		}
+	}
+
+	// Do oneof fields.
+	if prop.oneofMarshaler != nil {
+		m := structPointer_Interface(base, prop.stype).(Message)
+		if err := prop.oneofMarshaler(m, o); err == ErrNil {
+			return errOneofHasNil
+		} else if err != nil {
+			return err
+		}
+	}
+
+	// Add unrecognized fields at the end.
+	if prop.unrecField.IsValid() {
+		v := *structPointer_Bytes(base, prop.unrecField)
+		if len(o.buf)+len(v) > maxMarshalSize {
+			return ErrTooLarge
+		}
+		if len(v) > 0 {
+			o.buf = append(o.buf, v...)
+		}
+	}
+
+	return state.err
+}
+
+func size_struct(prop *StructProperties, base structPointer) (n int) {
+	for _, i := range prop.order {
+		p := prop.Prop[i]
+		if p.size != nil {
+			n += p.size(p, base)
+		}
+	}
+
+	// Add unrecognized fields at the end.
+	if prop.unrecField.IsValid() {
+		v := *structPointer_Bytes(base, prop.unrecField)
+		n += len(v)
+	}
+
+	// Factor in any oneof fields.
+	if prop.oneofSizer != nil {
+		m := structPointer_Interface(base, prop.stype).(Message)
+		n += prop.oneofSizer(m)
+	}
+
+	return
+}
+
+var zeroes [20]byte // longer than any conceivable sizeVarint
+
+// Encode a struct, preceded by its encoded length (as a varint).
+func (o *Buffer) enc_len_struct(prop *StructProperties, base structPointer, state *errorState) error {
+	return o.enc_len_thing(func() error { return o.enc_struct(prop, base) }, state)
+}
+
+// Encode something, preceded by its encoded length (as a varint).
+func (o *Buffer) enc_len_thing(enc func() error, state *errorState) error {
+	iLen := len(o.buf)
+	o.buf = append(o.buf, 0, 0, 0, 0) // reserve four bytes for length
+	iMsg := len(o.buf)
+	err := enc()
+	if err != nil && !state.shouldContinue(err, nil) {
+		return err
+	}
+	lMsg := len(o.buf) - iMsg
+	lLen := sizeVarint(uint64(lMsg))
+	switch x := lLen - (iMsg - iLen); {
+	case x > 0: // actual length is x bytes larger than the space we reserved
+		// Move msg x bytes right.
+		o.buf = append(o.buf, zeroes[:x]...)
+		copy(o.buf[iMsg+x:], o.buf[iMsg:iMsg+lMsg])
+	case x < 0: // actual length is x bytes smaller than the space we reserved
+		// Move msg x bytes left.
+		copy(o.buf[iMsg+x:], o.buf[iMsg:iMsg+lMsg])
+		o.buf = o.buf[:len(o.buf)+x] // x is negative
+	}
+	// Encode the length in the reserved space.
+	o.buf = o.buf[:iLen]
+	o.EncodeVarint(uint64(lMsg))
+	o.buf = o.buf[:len(o.buf)+lMsg]
+	return state.err
+}
+
+// errorState maintains the first error that occurs and updates that error
+// with additional context.
+type errorState struct {
+	err error
+}
+
+// shouldContinue reports whether encoding should continue upon encountering the
+// given error. If the error is RequiredNotSetError, shouldContinue returns true
+// and, if this is the first appearance of that error, remembers it for future
+// reporting.
+//
+// If prop is not nil, it may update any error with additional context about the
+// field with the error.
+func (s *errorState) shouldContinue(err error, prop *Properties) bool {
+	// Ignore unset required fields.
+	reqNotSet, ok := err.(*RequiredNotSetError)
+	if !ok {
+		return false
+	}
+	if s.err == nil {
+		if prop != nil {
+			err = &RequiredNotSetError{prop.Name + "." + reqNotSet.field}
+		}
+		s.err = err
+	}
+	return true
+}

vendor/github.com/golang/protobuf/proto/equal.go

+// Go support for Protocol Buffers - Google's data interchange format
+//
+// Copyright 2011 The Go Authors.  All rights reserved.
+// https://github.com/golang/protobuf
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Protocol buffer comparison.
+
+package proto
+
+import (
+	"bytes"
+	"log"
+	"reflect"
+	"strings"
+)
+
+/*
+Equal returns true iff protocol buffers a and b are equal.
+The arguments must both be pointers to protocol buffer structs.
+
+Equality is defined in this way:
+  - Two messages are equal iff they are the same type,
+    corresponding fields are equal, unknown field sets
+    are equal, and extensions sets are equal.
+  - Two set scalar fields are equal iff their values are equal.
+    If the fields are of a floating-point type, remember that
+    NaN != x for all x, including NaN. If the message is defined
+    in a proto3 .proto file, fields are not "set"; specifically,
+    zero length proto3 "bytes" fields are equal (nil == {}).
+  - Two repeated fields are equal iff their lengths are the same,
+    and their corresponding elements are equal (a "bytes" field,
+    although represented by []byte, is not a repeated field)
+  - Two unset fields are equal.
+  - Two unknown field sets are equal if their current
+    encoded state is equal.
+  - Two extension sets are equal iff they have corresponding
+    elements that are pairwise equal.
+  - Every other combination of things are not equal.
+
+The return value is undefined if a and b are not protocol buffers.
+*/
+func Equal(a, b Message) bool {
+	if a == nil || b == nil {
+		return a == b
+	}
+	v1, v2 := reflect.ValueOf(a), reflect.ValueOf(b)
+	if v1.Type() != v2.Type() {
+		return false
+	}
+	if v1.Kind() == reflect.Ptr {
+		if v1.IsNil() {
+			return v2.IsNil()
+		}
+		if v2.IsNil() {
+			return false
+		}
+		v1, v2 = v1.Elem(), v2.Elem()
+	}
+	if v1.Kind() != reflect.Struct {
+		return false
+	}
+	return equalStruct(v1, v2)
+}
+
+// v1 and v2 are known to have the same type.
+func equalStruct(v1, v2 reflect.Value) bool {
+	sprop := GetProperties(v1.Type())
+	for i := 0; i < v1.NumField(); i++ {
+		f := v1.Type().Field(i)
+		if strings.HasPrefix(f.Name, "XXX_") {
+			continue
+		}
+		f1, f2 := v1.Field(i), v2.Field(i)
+		if f.Type.Kind() == reflect.Ptr {
+			if n1, n2 := f1.IsNil(), f2.IsNil(); n1 && n2 {
+				// both unset
+				continue
+			} else if n1 != n2 {
+				// set/unset mismatch
+				return false
+			}
+			b1, ok := f1.Interface().(raw)
+			if ok {
+				b2 := f2.Interface().(raw)
+				// RawMessage
+				if !bytes.Equal(b1.Bytes(), b2.Bytes()) {
+					return false
+				}
+				continue
+			}
+			f1, f2 = f1.Elem(), f2.Elem()
+		}
+		if !equalAny(f1, f2, sprop.Prop[i]) {
+			return false
+		}
+	}
+
+	if em1 := v1.FieldByName("XXX_InternalExtensions"); em1.IsValid() {
+		em2 := v2.FieldByName("XXX_InternalExtensions")
+		if !equalExtensions(v1.Type(), em1.Interface().(XXX_InternalExtensions), em2.Interface().(XXX_InternalExtensions)) {
+			return false
+		}
+	}
+
+	if em1 := v1.FieldByName("XXX_extensions"); em1.IsValid() {
+		em2 := v2.FieldByName("XXX_extensions")
+		if !equalExtMap(v1.Type(), em1.Interface().(map[int32]Extension), em2.Interface().(map[int32]Extension)) {
+			return false
+		}
+	}
+
+	uf := v1.FieldByName("XXX_unrecognized")
+	if !uf.IsValid() {
+		return true
+	}
+
+	u1 := uf.Bytes()
+	u2 := v2.FieldByName("XXX_unrecognized").Bytes()
+	if !bytes.Equal(u1, u2) {
+		return false
+	}
+
+	return true
+}
+
+// v1 and v2 are known to have the same type.
+// prop may be nil.
+func equalAny(v1, v2 reflect.Value, prop *Properties) bool {
+	if v1.Type() == protoMessageType {
+		m1, _ := v1.Interface().(Message)
+		m2, _ := v2.Interface().(Message)
+		return Equal(m1, m2)
+	}
+	switch v1.Kind() {
+	case reflect.Bool:
+		return v1.Bool() == v2.Bool()
+	case reflect.Float32, reflect.Float64:
+		return v1.Float() == v2.Float()
+	case reflect.Int32, reflect.Int64:
+		return v1.Int() == v2.Int()
+	case reflect.Interface:
+		// Probably a oneof field; compare the inner values.
+		n1, n2 := v1.IsNil(), v2.IsNil()
+		if n1 || n2 {
+			return n1 == n2
+		}
+		e1, e2 := v1.Elem(), v2.Elem()
+		if e1.Type() != e2.Type() {
+			return false
+		}
+		return equalAny(e1, e2, nil)
+	case reflect.Map:
+		if v1.Len() != v2.Len() {
+			return false
+		}
+		for _, key := range v1.MapKeys() {
+			val2 := v2.MapIndex(key)
+			if !val2.IsValid() {
+				// This key was not found in the second map.
+				return false
+			}
+			if !equalAny(v1.MapIndex(key), val2, nil) {
+				return false
+			}
+		}
+		return true
+	case reflect.Ptr:
+		// Maps may have nil values in them, so check for nil.
+		if v1.IsNil() && v2.IsNil() {
+			return true
+		}
+		if v1.IsNil() != v2.IsNil() {
+			return false
+		}
+		return equalAny(v1.Elem(), v2.Elem(), prop)
+	case reflect.Slice:
+		if v1.Type().Elem().Kind() == reflect.Uint8 {
+			// short circuit: []byte
+
+			// Edge case: if this is in a proto3 message, a zero length
+			// bytes field is considered the zero value.
+			if prop != nil && prop.proto3 && v1.Len() == 0 && v2.Len() == 0 {
+				return true
+			}
+			if v1.IsNil() != v2.IsNil() {
+				return false
+			}
+			return bytes.Equal(v1.Interface().([]byte), v2.Interface().([]byte))
+		}
+
+		if v1.Len() != v2.Len() {
+			return false
+		}
+		for i := 0; i < v1.Len(); i++ {
+			if !equalAny(v1.Index(i), v2.Index(i), prop) {
+				return false
+			}
+		}
+		return true
+	case reflect.String:
+		return v1.Interface().(string) == v2.Interface().(string)
+	case reflect.Struct:
+		return equalStruct(v1, v2)
+	case reflect.Uint32, reflect.Uint64:
+		return v1.Uint() == v2.Uint()
+	}
+
+	// unknown type, so not a protocol buffer
+	log.Printf("proto: don't know how to compare %v", v1)
+	return false
+}
+
+// base is the struct type that the extensions are based on.
+// x1 and x2 are InternalExtensions.
+func equalExtensions(base reflect.Type, x1, x2 XXX_InternalExtensions) bool {
+	em1, _ := x1.extensionsRead()
+	em2, _ := x2.extensionsRead()
+	return equalExtMap(base, em1, em2)
+}
+
+func equalExtMap(base reflect.Type, em1, em2 map[int32]Extension) bool {
+	if len(em1) != len(em2) {
+		return false
+	}
+
+	for extNum, e1 := range em1 {
+		e2, ok := em2[extNum]
+		if !ok {
+			return false
+		}
+
+		m1, m2 := e1.value, e2.value
+
+		if m1 != nil && m2 != nil {
+			// Both are unencoded.
+			if !equalAny(reflect.ValueOf(m1), reflect.ValueOf(m2), nil) {
+				return false
+			}
+			continue
+		}
+
+		// At least one is encoded. To do a semantically correct comparison
+		// we need to unmarshal them first.
+		var desc *ExtensionDesc
+		if m := extensionMaps[base]; m != nil {
+			desc = m[extNum]
+		}
+		if desc == nil {
+			log.Printf("proto: don't know how to compare extension %d of %v", extNum, base)
+			continue
+		}
+		var err error
+		if m1 == nil {
+			m1, err = decodeExtension(e1.enc, desc)
+		}
+		if m2 == nil && err == nil {
+			m2, err = decodeExtension(e2.enc, desc)
+		}
+		if err != nil {
+			// The encoded form is invalid.
+			log.Printf("proto: badly encoded extension %d of %v: %v", extNum, base, err)
+			return false
+		}
+		if !equalAny(reflect.ValueOf(m1), reflect.ValueOf(m2), nil) {
+			return false
+		}
+	}
+
+	return true
+}