Fix for bug #7397. Changed space manager to allows negative values

for rect regions

layout/base/public/nsISpaceManager.h

@@ -101,7 +101,10 @@ public:
   NS_IMETHOD GetTranslation(nscoord& aX, nscoord& aY) const = 0;
 
   /**
-   * Returns the y-most of the bottommost band, or 0 if there are no bands.
+   * Returns the y-most of the bottommost band or 0 if there are no bands.
+   *
+   * @return  NS_OK if there are bands and NS_COMFALSE if there are
+   *          no bands
    */
   NS_IMETHOD YMost(nscoord& aYMost) const = 0;
 
@@ -133,16 +136,12 @@ public:
    * Add a rectangular region of unavailable space. The space is relative to
    * the local coordinate system.
    *
-   * The region is tagged with a frame. When translated to world coordinates
-   * the origin of the rect MUST be within the defined coordinate space, i.e.
-   * the x-offset and y-offset must be >= 0
+   * The region is tagged with a frame
    *
    * @param   aFrame the frame used to identify the region. Must not be NULL
    * @param   aUnavailableSpace the bounding rect of the unavailable space
    * @return  NS_OK if successful
    *          NS_ERROR_FAILURE if there is already a region tagged with aFrame
-   *          NS_ERROR_INVALID_ARG if the rect translated to world coordinates
-   *            is not within the defined coordinate space
    */
   NS_IMETHOD AddRectRegion(nsIFrame*     aFrame,
                            const nsRect& aUnavailableSpace) = 0;
@@ -153,8 +152,7 @@ public:
    * rect. You specify whether the width change applies to the left or right edge
    *
    * Returns NS_OK if successful, NS_ERROR_INVALID_ARG if there is no region
-   * tagged with aFrame, and NS_ERROR_FAILURE if the new offset when translated
-   * to world coordinates is outside the defined coordinate space
+   * tagged with aFrame
    */
   enum AffectedEdge {LeftEdge, RightEdge};
   NS_IMETHOD ResizeRectRegion(nsIFrame*    aFrame,
@@ -166,8 +164,7 @@ public:
    * Offset the region associated with aFrame by the specified amount.
    *
    * Returns NS_OK if successful, NS_ERROR_INVALID_ARG if there is no region
-   * tagged with aFrame, and NS_ERROR_FAILURE if the new offset when translated
-   * to world coordinates is outside the defined coordinate space
+   * tagged with aFrame
    */
   NS_IMETHOD OffsetRegion(nsIFrame* aFrame, nscoord dx, nscoord dy) = 0;
 

layout/base/src/nsSpaceManager.cpp

@@ -43,8 +43,10 @@ NS_RemoveFrameInfoEntries(PLHashEntry* he, PRIntn i, void* arg)
 /////////////////////////////////////////////////////////////////////////////
 // BandList
 
+#define NSCOORD_MIN (-2147483647 - 1) /* minimum signed value */
+
 nsSpaceManager::BandList::BandList()
-  : nsSpaceManager::BandRect(-1, -1, -1, -1, (nsIFrame*)nsnull)
+  : nsSpaceManager::BandRect(NSCOORD_MIN, NSCOORD_MIN, NSCOORD_MIN, NSCOORD_MIN, (nsIFrame*)nsnull)
 {
   PR_INIT_CLIST(this);
   numFrames = 0;
@@ -122,15 +124,20 @@ nsSpaceManager::GetTranslation(nscoord& aX, nscoord& aY) const
 NS_IMETHODIMP
 nsSpaceManager::YMost(nscoord& aYMost) const
 {
+  nsresult  result;
+
   if (mBandList.IsEmpty()) {
     aYMost = 0;
+    result = NS_COMFALSE;
+
   } else {
     BandRect* lastRect = mBandList.Tail();
 
     aYMost = lastRect->bottom;
+    result = NS_OK;
   }
 
-  return NS_OK;
+  return result;
 }
 
 /**
@@ -266,8 +273,8 @@ nsSpaceManager::GetBandData(nscoord       aYOffset,
   // If there are no unavailable rects or the offset is below the bottommost
   // band, then all the space is available
   nscoord yMost;
-  YMost(yMost);
-  if (y >= yMost) {
+  
+  if ((NS_COMFALSE == YMost(yMost)) || (y >= yMost)) {
     // All the requested space is available
     aBandData.count = 1;
     aBandData.trapezoids[0] = nsRect(0, aYOffset, aMaxSize.width, aMaxSize.height);
@@ -618,8 +625,7 @@ nsSpaceManager::InsertBandRect(BandRect* aBandRect)
   // If there are no existing bands or this rect is below the bottommost
   // band, then add a new band
   nscoord yMost;
-  YMost(yMost);
-  if (aBandRect->top >= yMost) {
+  if ((NS_COMFALSE == YMost(yMost)) || (aBandRect->top >= yMost)) {
     mBandList.Append(aBandRect);
     return;
   }
@@ -725,12 +731,6 @@ nsSpaceManager::AddRectRegion(nsIFrame* aFrame, const nsRect& aUnavailableSpace)
   nsRect  rect(aUnavailableSpace.x + mX, aUnavailableSpace.y + mY,
                aUnavailableSpace.width, aUnavailableSpace.height);
 
-  // Verify that the offset is within the defined coordinate space
-  if ((rect.x < 0) || (rect.y < 0)) {
-    NS_WARNING("invalid offset for rect region");
-    return NS_ERROR_INVALID_ARG;
-  }
-
   // Create a frame info structure
   frameInfo = CreateFrameInfo(aFrame, rect);
   if (nsnull == frameInfo) {
@@ -775,12 +775,6 @@ nsSpaceManager::ResizeRectRegion(nsIFrame*    aFrame,
     rect.x += aDeltaWidth;
   }
 
-  // Verify that the offset is within the defined coordinate space
-  if ((rect.x < 0) || (rect.y < 0)) {
-    NS_WARNING("invalid offset when resizing rect region");
-    return NS_ERROR_FAILURE;
-  }
-
   // For the time being just remove it and add it back in. Because
   // AddRectRegion() operates relative to the local coordinate space,
   // translate from world coordinates to the local coordinate space
@@ -804,12 +798,6 @@ nsSpaceManager::OffsetRegion(nsIFrame* aFrame, nscoord aDx, nscoord aDy)
   nsRect  rect(frameInfo->rect);
   rect.MoveBy(aDx, aDy);
 
-  // Verify that the offset is within the defined coordinate space
-  if ((rect.x < 0) || (rect.y < 0)) {
-    NS_WARNING("invalid offset when offseting rect region");
-    return NS_ERROR_FAILURE;
-  }
-
   // For the time being just remove it and add it back in. Because
   // AddRectRegion() operates relative to the local coordinate space,
   // translate from world coordinates to the local coordinate space

layout/base/src/nsSpaceManager.h

@@ -132,7 +132,7 @@ public:
 protected:
   nsIFrame* const mFrame;     // frame associated with the space manager
   nscoord         mX, mY;     // translation from local to global coordinate space
-  BandList        mBandList;  // header for circular linked list of band rects
+  BandList        mBandList;  // header/sentinel for circular linked list of band rects
   PLHashTable*    mFrameInfoMap;
 
 protected:

layout/generic/nsSpaceManager.cpp

@@ -43,8 +43,10 @@ NS_RemoveFrameInfoEntries(PLHashEntry* he, PRIntn i, void* arg)
 /////////////////////////////////////////////////////////////////////////////
 // BandList
 
+#define NSCOORD_MIN (-2147483647 - 1) /* minimum signed value */
+
 nsSpaceManager::BandList::BandList()
-  : nsSpaceManager::BandRect(-1, -1, -1, -1, (nsIFrame*)nsnull)
+  : nsSpaceManager::BandRect(NSCOORD_MIN, NSCOORD_MIN, NSCOORD_MIN, NSCOORD_MIN, (nsIFrame*)nsnull)
 {
   PR_INIT_CLIST(this);
   numFrames = 0;
@@ -122,15 +124,20 @@ nsSpaceManager::GetTranslation(nscoord& aX, nscoord& aY) const
 NS_IMETHODIMP
 nsSpaceManager::YMost(nscoord& aYMost) const
 {
+  nsresult  result;
+
   if (mBandList.IsEmpty()) {
     aYMost = 0;
+    result = NS_COMFALSE;
+
   } else {
     BandRect* lastRect = mBandList.Tail();
 
     aYMost = lastRect->bottom;
+    result = NS_OK;
   }
 
-  return NS_OK;
+  return result;
 }
 
 /**
@@ -266,8 +273,8 @@ nsSpaceManager::GetBandData(nscoord       aYOffset,
   // If there are no unavailable rects or the offset is below the bottommost
   // band, then all the space is available
   nscoord yMost;
-  YMost(yMost);
-  if (y >= yMost) {
+  
+  if ((NS_COMFALSE == YMost(yMost)) || (y >= yMost)) {
     // All the requested space is available
     aBandData.count = 1;
     aBandData.trapezoids[0] = nsRect(0, aYOffset, aMaxSize.width, aMaxSize.height);
@@ -618,8 +625,7 @@ nsSpaceManager::InsertBandRect(BandRect* aBandRect)
   // If there are no existing bands or this rect is below the bottommost
   // band, then add a new band
   nscoord yMost;
-  YMost(yMost);
-  if (aBandRect->top >= yMost) {
+  if ((NS_COMFALSE == YMost(yMost)) || (aBandRect->top >= yMost)) {
     mBandList.Append(aBandRect);
     return;
   }
@@ -725,12 +731,6 @@ nsSpaceManager::AddRectRegion(nsIFrame* aFrame, const nsRect& aUnavailableSpace)
   nsRect  rect(aUnavailableSpace.x + mX, aUnavailableSpace.y + mY,
                aUnavailableSpace.width, aUnavailableSpace.height);
 
-  // Verify that the offset is within the defined coordinate space
-  if ((rect.x < 0) || (rect.y < 0)) {
-    NS_WARNING("invalid offset for rect region");
-    return NS_ERROR_INVALID_ARG;
-  }
-
   // Create a frame info structure
   frameInfo = CreateFrameInfo(aFrame, rect);
   if (nsnull == frameInfo) {
@@ -775,12 +775,6 @@ nsSpaceManager::ResizeRectRegion(nsIFrame*    aFrame,
     rect.x += aDeltaWidth;
   }
 
-  // Verify that the offset is within the defined coordinate space
-  if ((rect.x < 0) || (rect.y < 0)) {
-    NS_WARNING("invalid offset when resizing rect region");
-    return NS_ERROR_FAILURE;
-  }
-
   // For the time being just remove it and add it back in. Because
   // AddRectRegion() operates relative to the local coordinate space,
   // translate from world coordinates to the local coordinate space
@@ -804,12 +798,6 @@ nsSpaceManager::OffsetRegion(nsIFrame* aFrame, nscoord aDx, nscoord aDy)
   nsRect  rect(frameInfo->rect);
   rect.MoveBy(aDx, aDy);
 
-  // Verify that the offset is within the defined coordinate space
-  if ((rect.x < 0) || (rect.y < 0)) {
-    NS_WARNING("invalid offset when offseting rect region");
-    return NS_ERROR_FAILURE;
-  }
-
   // For the time being just remove it and add it back in. Because
   // AddRectRegion() operates relative to the local coordinate space,
   // translate from world coordinates to the local coordinate space

layout/generic/nsSpaceManager.h

@@ -132,7 +132,7 @@ public:
 protected:
   nsIFrame* const mFrame;     // frame associated with the space manager
   nscoord         mX, mY;     // translation from local to global coordinate space
-  BandList        mBandList;  // header for circular linked list of band rects
+  BandList        mBandList;  // header/sentinel for circular linked list of band rects
   PLHashTable*    mFrameInfoMap;
 
 protected: