Use unique IDs to identify PTYWindow in scripting rather than indexes. The...

Use unique IDs to identify PTYWindow in scripting rather than indexes. The notion of windows being ordered is misbegotten. It causes issues like #4157.

iTerm2.sdef

@@ -101,7 +101,10 @@
     </class> 
     <class name="window" code="cwin" description="A window."> 
       <cocoa class="PTYWindow"/> 
-      <property name="name" code="pnam" type="text" access="r" 
+      <property name="id" code="ID  " description="The unique identifier of the session." type="text" access="r">
+        <cocoa key="windowIdentifier"/>
+      </property>
+      <property name="name" code="pnam" type="text" access="r"
         description="The full title of the window."> 
         <cocoa key="title"/> 
       </property> 

sources/PTYWindow+Scripting.m

@@ -7,7 +7,6 @@
 @implementation PTYWindow (Scripting)
-// Object specifier
 - (NSScriptObjectSpecifier *)objectSpecifier {
     NSUInteger anIndex = 0;
     id classDescription = nil;
@@ -19,12 +18,10 @@
     if (anIndex != NSNotFound) {
         containerRef = [NSApp objectSpecifier];
         classDescription = [NSClassDescription classDescriptionForClass:[NSApp class]];
-        // Create and return the specifier
-        return [[[NSIndexSpecifier alloc]
-                   initWithContainerClassDescription:classDescription
-                                  containerSpecifier:containerRef
-                                                 key:@"orderedTerminalWindows"
-                                               index:anIndex] autorelease];
+        return [[[NSUniqueIDSpecifier alloc] initWithContainerClassDescription:classDescription
+                                                            containerSpecifier:containerRef
+                                                                           key:@"orderedTerminalWindows"
+                                                                      uniqueID:self.windowIdentifier] autorelease];
     } else {
         return nil;
     }

sources/PTYWindow.h

@@ -38,6 +38,8 @@
 @property(nonatomic, readonly) int screenNumber;
 @property(nonatomic, readonly, getter=isTogglingLionFullScreen) BOOL togglingLionFullScreen;
+// A unique identifier that does not get recycled during the program's lifetime.
+@property(nonatomic, readonly) NSString *windowIdentifier;
 - (void)smartLayout;
 - (void)setLayoutDone;

sources/PTYWindow.m

@@ -52,6 +52,7 @@
     BOOL isTogglingLionFullScreen_;
     NSObject *restoreState_;
     iTermDelayedTitleSetter *_titleSetter;
+    NSInteger _uniqueNumber;
 }
 - (void)dealloc {
@@ -75,6 +76,14 @@
             self.delegate];
 }
+- (NSString *)windowIdentifier {
+    if (!_uniqueNumber) {
+        static NSInteger nextUniqueNumber = 1;
+        _uniqueNumber = nextUniqueNumber++;
+    }
+    return [NSString stringWithFormat:@"window-%ld", (long)_uniqueNumber];
+}
+
 - (void)encodeRestorableStateWithCoder:(NSCoder *)coder {
     [super encodeRestorableStateWithCoder:coder];
     [coder encodeObject:restoreState_ forKey:kPseudoTerminalStateRestorationWindowArrangementKey];