[Bug-1630262], [Bug-1615425]: segfault when deleting lines or tagging outside of the -startline/-endline range with peer text widgets. [Bug-3487407]: Weird text indices.

FossilOrigin-Name: 5528cb094a83ae9ef719e4084d6b321ab347ead5

4 files changed, 101 insertions, 17 deletions

diff --git a/generic/tkText.c b/generic/tkText.c
index 98720d3..d1f489d 100644
--- a/generic/tkText.c
+++ b/generic/tkText.c
@@ -2119,6 +2119,10 @@ ConfigureText(
 	 * Also, clamp the insert and current (unshared) marks to the new
 	 * -startline/-endline range limits of the widget. All other (shared)
 	 * marks are unchanged.
+         * The return value of TkTextMarkNameToIndex does not need to be
+         * checked: "insert" and "current" marks always exist, and the
+         * purpose of the code below precisely is to move them inside the
+         * -startline/-endline range.
 	 */
 
 	textPtr->sharedTextPtr->stateEpoch++;
@@ -3105,6 +3109,11 @@ DeleteIndexRange(
 		resetView = 1;
 		line = line1;
 		byteIndex = tPtr->topIndex.byteIndex;
+            } else {
+                /*
+                 * Deletion range starts after the top line. This peers's view
+                 * will not need to be reset. Nothing to do.
+                 */
 	    }
 	} else if (index2.linePtr == tPtr->topIndex.linePtr) {
 	    /*
@@ -3121,6 +3130,11 @@ DeleteIndexRange(
 	    } else {
 		byteIndex -= (index2.byteIndex - index1.byteIndex);
 	    }
+        } else {
+            /*
+             * Deletion range ends before the top line. This peers's view
+             * will not need to be reset. Nothing to do.
+             */
 	}
 	if (resetView) {
 	    lineAndByteIndex[resetViewCount] = line;
@@ -3165,14 +3179,43 @@ DeleteIndexRange(
 	    TkTextIndex indexTmp;
 
 	    if (tPtr == textPtr) {
-		if (viewUpdate) {
+                if (viewUpdate) {
+                    /*
+                     * line cannot be before -startline of textPtr because
+                     * this line corresponds to an index which is necessarily
+                     * between "1.0" and "end" relative to textPtr.
+                     * Therefore no need to clamp line to the -start/-end
+                     * range.
+                     */
+
 		    TkTextMakeByteIndex(sharedTextPtr->tree, textPtr, line,
 			    byteIndex, &indexTmp);
 		    TkTextSetYView(tPtr, &indexTmp, 0);
 		}
 	    } else {
-		TkTextMakeByteIndex(sharedTextPtr->tree, NULL, line,
+                TkTextMakeByteIndex(sharedTextPtr->tree, tPtr, line,
 			byteIndex, &indexTmp);
+                /*
+                 * line may be before -startline of tPtr and must be
+                 * clamped to -startline before providing it to
+                 * TkTextSetYView otherwise lines before -startline
+                 * would be displayed.
+                 * There is no need to worry about -endline however,
+                 * because the view will only be reset if the deletion
+                 * involves the TOP line of the screen
+                 */
+
+                if (tPtr->start != NULL) {
+                    int start;
+                    TkTextIndex indexStart;
+
+                    start = TkBTreeLinesTo(NULL, tPtr->start);
+                    TkTextMakeByteIndex(sharedTextPtr->tree, NULL, start,
+			    0, &indexStart);
+                    if (TkTextIndexCmp(&indexTmp, &indexStart) < 0) {
+                        indexTmp = indexStart;
+                    }
+                }
 		TkTextSetYView(tPtr, &indexTmp, 0);
 	    }
 	}
diff --git a/generic/tkTextBTree.c b/generic/tkTextBTree.c
index 572c623..e34dae7 100644
--- a/generic/tkTextBTree.c
+++ b/generic/tkTextBTree.c
@@ -658,12 +658,12 @@ AdjustStartEndRefs(
 	if (textPtr->start != NULL) {
 	    count--;
 	    treePtr->startEnd[count] = textPtr->start;
-	    treePtr->startEndRef[count] = treePtr->sharedTextPtr->peers;
+	    treePtr->startEndRef[count] = textPtr;
 	}
 	if (textPtr->end != NULL) {
 	    count--;
 	    treePtr->startEnd[count] = textPtr->end;
-	    treePtr->startEndRef[count] = treePtr->sharedTextPtr->peers;
+	    treePtr->startEndRef[count] = textPtr;
 	}
     }
 }
@@ -1606,7 +1606,7 @@ TkBTreeFindLine(
     }
 
     /*
-     * Check for the any start/end offset for this text widget.
+     * Check for any start/end offset for this text widget.
      */
 
     if (textPtr != NULL) {
@@ -1988,12 +1988,37 @@ TkBTreeLinesTo(
 	    index += nodePtr2->numLines;
 	}
     }
-    if (textPtr != NULL && textPtr->start != NULL) {
-	index -= TkBTreeLinesTo(NULL, textPtr->start);
+    if (textPtr != NULL) {
+        /* 
+         * The index to return must be relative to textPtr, not to the entire
+         * tree. Take care to never return a negative index when linePtr
+         * denotes a line before -startline, or an index larger than the
+         * number of lines in textPtr when linePtr is a line past -endline.
+         */
+
+        int indexStart, indexEnd;
+
+        if (textPtr->start != NULL) {
+            indexStart = TkBTreeLinesTo(NULL, textPtr->start);
+        } else {
+            indexStart = 0;
+        }
+        if (textPtr->end != NULL) {
+            indexEnd = TkBTreeLinesTo(NULL, textPtr->end);
+        } else {
+            indexEnd = TkBTreeNumLines(textPtr->sharedTextPtr->tree, NULL);
+        }
+        if (index < indexStart) {
+            index = 0;
+        } else if (index > indexEnd) {
+            index = TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr);
+        } else {
+            index -= indexStart;
+        }
     }
     return index;
 }
-
+
 /*
  *----------------------------------------------------------------------
  *
diff --git a/generic/tkTextDisp.c b/generic/tkTextDisp.c
index 249f476..b3d94ec 100644
--- a/generic/tkTextDisp.c
+++ b/generic/tkTextDisp.c
@@ -1972,7 +1972,7 @@ UpdateDisplayInfo(
 
 	if (spaceLeft <= dInfoPtr->newTopPixelOffset) {
 	    /*
-	     * We can full up all the needed space just by showing more of the
+	     * We can fill up all the needed space just by showing more of the
 	     * current top line.
 	     */
 
@@ -3231,7 +3231,7 @@ TextInvalidateLineMetrics(
 	 */
 
 	TkBTreeLinePixelEpoch(textPtr, linePtr) = 0;
-	while (counter > 0 && linePtr != 0) {
+	while (counter > 0 && linePtr != NULL) {
 	    linePtr = TkBTreeNextLine(textPtr, linePtr);
 	    if (linePtr != NULL) {
 		TkBTreeLinePixelEpoch(textPtr, linePtr) = 0;
@@ -3246,7 +3246,7 @@ TextInvalidateLineMetrics(
 	 * more lines than is strictly necessary (but the examination of the
 	 * extra lines should be quick, since their pixelCalculationEpoch will
 	 * be up to date). However, to keep track of that would require more
-	 * complex record-keeping that what we have.
+	 * complex record-keeping than what we have.
 	 */
 
 	if (dInfoPtr->lineUpdateTimer == NULL) {
diff --git a/generic/tkTextMark.c b/generic/tkTextMark.c
index 9729449..76ab1a9 100644
--- a/generic/tkTextMark.c
+++ b/generic/tkTextMark.c
@@ -286,6 +286,7 @@ TkTextSetMark(
 
 	if (markPtr == textPtr->insertMarkPtr) {
 	    TkTextIndex index, index2;
+            int nblines;
 
 	    TkTextMarkSegToIndex(textPtr, textPtr->insertMarkPtr, &index);
 	    TkTextIndexForwChars(NULL, &index, 1, &index2, COUNT_INDICES);
@@ -296,9 +297,18 @@ TkTextSetMark(
 	     */
 
 	    TkTextChanged(NULL, textPtr, &index, &index2);
-	    if (TkBTreeLinesTo(textPtr, indexPtr->linePtr) ==
-		    TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr)) {
-		TkTextIndexBackChars(NULL, indexPtr, 1, &insertIndex,
+
+            /*
+             * The number of lines in the widget is zero if and only if it is
+             * a partial peer with -startline == -endline, i.e. an empty
+             * peer. In this case the mark shall be set exactly at the given
+             * index, and not one character backwards (bug 3487407).
+             */
+
+	    nblines = TkBTreeNumLines(textPtr->sharedTextPtr->tree, textPtr);
+	    if ((TkBTreeLinesTo(textPtr, indexPtr->linePtr) == nblines)
+		    && (nblines > 0))  {
+		TkTextIndexBackChars(NULL,indexPtr, 1, &insertIndex,
 			COUNT_INDICES);
 		indexPtr = &insertIndex;
 	    }
@@ -386,9 +396,15 @@ TkTextMarkSegToIndex(
  *
  * Results:
  *	The return value is TCL_OK if "name" exists as a mark in the text
- *	widget. In this case *indexPtr is filled in with the next segment
- *	whose after the mark whose size is non-zero. TCL_ERROR is returned if
- *	the mark doesn't exist in the text widget.
+ *	widget and is located within its -starline/-endline range. In this
+ *	case *indexPtr is filled in with the next segment who is after the
+ *	mark whose size is non-zero. TCL_ERROR is returned if the mark
+ *	doesn't exist in the text widget, or if it is out of its -starline/
+ *	-endline range. In this latter case *indexPtr still contains valid
+ *	information, in particular TkTextMarkNameToIndex called with the
+ *	"insert" or "current" mark name may return TCL_ERROR, but *indexPtr
+ *	contains the correct index of this mark before -startline or after
+ *	-endline.
  *
  * Side effects:
  *	None.