Keep track of how many lines are in the prompt so the whole thing can be...

Keep track of how many lines are in the prompt so the whole thing can be preserved when you clear the buffer. Issue 1330.

iTerm2XCTests/VT100GridTest.m

@@ -1809,7 +1809,8 @@ do { \
     [lineBuffer setMaxLines:1];
     int dropped = [grid resetWithLineBuffer:lineBuffer
                         unlimitedScrollback:NO
-                         preserveCursorLine:NO];
+                         preserveCursorLine:NO
+                      additionalLinesToSave:0];
     XCTAssert(dropped == 2);
     XCTAssert([[grid compactLineDump] isEqualToString:
             @"....\n"
@@ -1830,7 +1831,8 @@ do { \
     [lineBuffer setMaxLines:1];
     dropped = [grid resetWithLineBuffer:lineBuffer
                     unlimitedScrollback:YES
-                     preserveCursorLine:NO];
+                     preserveCursorLine:NO
+                  additionalLinesToSave:0];
     XCTAssert(dropped == 0);
     XCTAssert([[grid compactLineDump] isEqualToString:
             @"....\n"
@@ -1845,7 +1847,8 @@ do { \
     [lineBuffer setMaxLines:1];
     dropped = [grid resetWithLineBuffer:lineBuffer
                     unlimitedScrollback:YES
-                     preserveCursorLine:NO];
+                     preserveCursorLine:NO
+                  additionalLinesToSave:0];
     XCTAssert(dropped == 0);
     XCTAssert([[grid compactLineDump] isEqualToString:
             @"..\n"
@@ -1865,7 +1868,8 @@ do { \
     [lineBuffer setMaxLines:1];
     int dropped = [grid resetWithLineBuffer:lineBuffer
                         unlimitedScrollback:NO
-                         preserveCursorLine:YES];
+                         preserveCursorLine:YES
+                      additionalLinesToSave:0];
     XCTAssert(dropped == 2);
     XCTAssert([[grid compactLineDump] isEqualToString:
             @"....\n"
@@ -1891,7 +1895,8 @@ do { \
     [lineBuffer setMaxLines:1];
     dropped = [grid resetWithLineBuffer:lineBuffer
                     unlimitedScrollback:NO
-                     preserveCursorLine:YES];
+                     preserveCursorLine:YES
+                  additionalLinesToSave:0];
     XCTAssert(dropped == 1);
     XCTAssert([[grid compactLineDump] isEqualToString:
             @"efgh\n"
@@ -1917,7 +1922,8 @@ do { \
     [lineBuffer setMaxLines:1];
     dropped = [grid resetWithLineBuffer:lineBuffer
                     unlimitedScrollback:NO
-                     preserveCursorLine:YES];
+                     preserveCursorLine:YES
+                  additionalLinesToSave:0];
     XCTAssert(dropped == 0);
     XCTAssert([[grid compactLineDump] isEqualToString:
             @"abcd\n"
@@ -1939,7 +1945,8 @@ do { \
     [lineBuffer setMaxLines:1];
     dropped = [grid resetWithLineBuffer:lineBuffer
                     unlimitedScrollback:YES
-                     preserveCursorLine:YES];
+                     preserveCursorLine:YES
+                  additionalLinesToSave:0];
     XCTAssert(dropped == 0);
     XCTAssert([[grid compactLineDump] isEqualToString:
             @"....\n"
@@ -1954,7 +1961,8 @@ do { \
     [lineBuffer setMaxLines:1];
     dropped = [grid resetWithLineBuffer:lineBuffer
                     unlimitedScrollback:YES
-                     preserveCursorLine:YES];
+                     preserveCursorLine:YES
+                  additionalLinesToSave:0];
     XCTAssert(dropped == 0);
     XCTAssert([[grid compactLineDump] isEqualToString:
             @"..\n"

sources/VT100Grid.h

@@ -134,7 +134,8 @@
 // for |leave|.
 - (int)resetWithLineBuffer:(LineBuffer *)lineBuffer
        unlimitedScrollback:(BOOL)unlimitedScrollback
-        preserveCursorLine:(BOOL)preserveCursorLine;
+        preserveCursorLine:(BOOL)preserveCursorLine
+     additionalLinesToSave:(int)additionalLinesToSave;
 // Move the grid contents up, leaving only the whole wrapped line the cursor is on at the top.
 - (void)moveWrappedCursorLineToTopOfGrid;

sources/VT100Grid.m

@@ -405,12 +405,13 @@ static NSString *const kGridSizeKey = @"Size";
 - (int)resetWithLineBuffer:(LineBuffer *)lineBuffer
         unlimitedScrollback:(BOOL)unlimitedScrollback
-        preserveCursorLine:(BOOL)preserveCursorLine {
+        preserveCursorLine:(BOOL)preserveCursorLine
+     additionalLinesToSave:(int)additionalLinesToSave {
     self.scrollRegionRows = VT100GridRangeMake(0, size_.height);
     self.scrollRegionCols = VT100GridRangeMake(0, size_.width);
     int numLinesToScroll;
     if (preserveCursorLine) {
-        numLinesToScroll = cursor_.y;
+        numLinesToScroll = MAX(0, cursor_.y - additionalLinesToSave);
     } else {
         numLinesToScroll = [self lineNumberOfLastNonEmptyLine] + 1;
     }
@@ -423,7 +424,7 @@ static NSString *const kGridSizeKey = @"Size";
     }
     self.cursor = VT100GridCoordMake(0, 0);
-    [self setCharsFrom:VT100GridCoordMake(0, preserveCursorLine ? 1 : 0)
+    [self setCharsFrom:VT100GridCoordMake(0, preserveCursorLine ? 1 + additionalLinesToSave : 0)
                     to:VT100GridCoordMake(size_.width - 1, size_.height - 1)
                 toChar:[self defaultChar]];

sources/VT100GridTypes.h

@@ -142,6 +142,10 @@ NS_INLINE BOOL VT100GridCoordEquals(VT100GridCoord a, VT100GridCoord b) {
     return a.x == b.x && a.y == b.y;
 }
+NS_INLINE BOOL VT100GridAbsCoordEquals(VT100GridAbsCoord a, VT100GridAbsCoord b) {
+    return a.x == b.x && a.y == b.y;
+}
+
 NS_INLINE BOOL VT100GridSizeEquals(VT100GridSize a, VT100GridSize b) {
     return a.width == b.width && a.height == b.height;
 }

sources/VT100Screen.m

@@ -154,12 +154,16 @@ static const double kInterBellQuietPeriod = 0.1;
     // base64 value to copy to pasteboard, being built up bit by bit.
     NSMutableString *_copyString;
+
+    // Valid while at the command prompt only. GIves the range of the current prompt. Meaningful
+    // only if the end is not equal to the start.
+    VT100GridAbsCoordRange _currentPromptRange;
 }
 static NSString *const kInlineFileName = @"name";  // NSString
 static NSString *const kInlineFileWidth = @"width";  // NSNumber
 static NSString *const kInlineFileWidthUnits = @"width units";  // NSNumber of VT100TerminalUnits
-static NSString *const kInlineFileHeight = @"height";  // NSNumb    er
+static NSString *const kInlineFileHeight = @"height";  // NSNumber
 static NSString *const kInlineFileHeightUnits = @"height units"; // NSNumber of VT100TerminalUnits
 static NSString *const kInlineFilePreserveAspectRatio = @"preserve aspect ratio";  // NSNumber bool
 static NSString *const kInlineFileBase64String = @"base64 string";  // NSMutableString
@@ -905,10 +909,16 @@ static NSString *const kInilineFileInset = @"inset";  // NSValue of NSEdgeInsets
     [delegate_ screenTriggerableChangeDidOccur];
     // This clears the screen.
     int x = currentGrid_.cursorX;
+    int numberOfPromptLines = 1;
+    if (!VT100GridAbsCoordEquals(_currentPromptRange.start, _currentPromptRange.end)) {
+        numberOfPromptLines = MAX(1, _currentPromptRange.end.y - _currentPromptRange.start.y + 1);
+    }
     [self incrementOverflowBy:[currentGrid_ resetWithLineBuffer:linebuffer_
                                             unlimitedScrollback:unlimitedScrollback_
-                                             preserveCursorLine:YES]];
+                                             preserveCursorLine:YES
+                                          additionalLinesToSave:MAX(0, numberOfPromptLines - 1)]];
     currentGrid_.cursorX = x;
+    currentGrid_.cursorY = numberOfPromptLines - 1;
 }
 - (void)clearScrollbackBuffer
@@ -2651,7 +2661,8 @@ static NSString *const kInilineFileInset = @"inset";  // NSValue of NSEdgeInsets
     } else {
         [self incrementOverflowBy:[currentGrid_ resetWithLineBuffer:linebuffer_
                                                 unlimitedScrollback:unlimitedScrollback_
-                                                 preserveCursorLine:NO]];
+                                                 preserveCursorLine:NO
+                                              additionalLinesToSave:0]];
     }
     [self setInitialTabStops];
@@ -3717,6 +3728,9 @@ static NSString *const kInilineFileInset = @"inset";  // NSValue of NSEdgeInsets
     _lastCommandOutputRange.end = coord;
     _lastCommandOutputRange.start = nextCommandOutputStart_;
+    _currentPromptRange.start = coord;
+    _currentPromptRange.end = coord;
+
     // FinalTerm uses this to define the start of a collapsable region. That would be a nightmare
     // to add to iTerm, and our answer to this is marks, which already existed anyway.
     [delegate_ screenPromptDidStartAtLine:[self numberOfScrollbackLines] + self.cursorY - 1];
@@ -3724,6 +3738,8 @@ static NSString *const kInilineFileInset = @"inset";  // NSValue of NSEdgeInsets
 - (void)terminalCommandDidStart {
     DLog(@"FinalTerm: terminalCommandDidStart");
+    _currentPromptRange.end = VT100GridAbsCoordMake(currentGrid_.cursor.x,
+                                                    currentGrid_.cursor.y + self.numberOfScrollbackLines + self.totalScrollbackOverflow);
     [self commandDidStartAtScreenCoord:currentGrid_.cursor];
     [delegate_ screenPromptDidEndAtLine:[self numberOfScrollbackLines] + self.cursorY - 1];
 }
@@ -3740,6 +3756,8 @@ static NSString *const kInilineFileInset = @"inset";  // NSValue of NSEdgeInsets
 - (void)terminalCommandDidEnd {
     DLog(@"FinalTerm: terminalCommandDidEnd");
+    _currentPromptRange.start = _currentPromptRange.end = VT100GridAbsCoordMake(0, 0);
+
     [self commandDidEndAtAbsCoord:VT100GridAbsCoordMake(currentGrid_.cursor.x, currentGrid_.cursor.y + [self numberOfScrollbackLines] + [self totalScrollbackOverflow])];
 }