Fix performance problem on home.netscape.com: Don't do full reflow of all absolutely positioned elements whose containing block is on the path to the target of an incremental reflow. b=146831 sr=waterson r=kin

layout/generic/nsAbsoluteContainingBlock.cpp

@@ -194,8 +194,11 @@ nsAbsoluteContainingBlock::Reflow(nsIFrame*                aDelegatingFrame,
   // Initialize OUT parameter
   aChildBounds.SetRect(0, 0, 0, 0);
 
-  // Make a copy of the reflow state. If the reason is eReflowReason_Incremental,
+  // Make a copy of the reflow state.  If the reason is
-  // then change it to eReflowReason_Resize
+  // eReflowReason_Incremental (which should mean either that the target
+  // is the frame for which this is the absolute container or that the
+  // container changed size due to incremental reflow of its children),
+  // then change it to eReflowReason_Resize.
   nsHTMLReflowState reflowState(aReflowState);
   if (eReflowReason_Incremental == reflowState.reason) {
     reflowState.reason = eReflowReason_Resize;

layout/generic/nsBlockFrame.cpp

@@ -729,6 +729,8 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
   }
 #endif
 
+  nsRect oldRect(mRect);
+
   // Should we create a space manager?
   nsAutoSpaceManager autoSpaceManager(NS_CONST_CAST(nsHTMLReflowState &, aReflowState));
 
@@ -739,8 +741,10 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
   if (NS_BLOCK_SPACE_MGR & mState)
     autoSpaceManager.CreateSpaceManagerFor(aPresContext, this);
 
-  // See if it's an incremental reflow command
+  // See if it's an incremental reflow command and we're not the target
-  if (eReflowReason_Incremental == aReflowState.reason) {
+  if (mAbsoluteContainer.HasAbsoluteFrames() &&
+      eReflowReason_Incremental == aReflowState.reason &&
+      !aReflowState.path->mReflowCommand) {
     // Give the absolute positioning code a chance to handle it
     nscoord containingBlockWidth;
     nscoord containingBlockHeight;
@@ -1021,7 +1025,18 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
   // Let the absolutely positioned container reflow any absolutely positioned
   // child frames that need to be reflowed, e.g., elements with a percentage
   // based width/height
-  if (NS_SUCCEEDED(rv) && mAbsoluteContainer.HasAbsoluteFrames()) {
+  // We want to do this under either of two conditions:
+  //  1. If we didn't do the incremental reflow above.
+  //  2. If our size changed.
+  // Even though it's the padding edge that's the containing block, we
+  // can use our rect (the border edge) since if the border style
+  // changed, the reflow would have been targeted at us so we'd satisfy
+  // condition 1.
+  if (NS_SUCCEEDED(rv) &&
+      mAbsoluteContainer.HasAbsoluteFrames() &&
+      (eReflowReason_Incremental != aReflowState.reason ||
+       aReflowState.path->mReflowCommand ||
+       mRect != oldRect)) {
     nscoord containingBlockWidth;
     nscoord containingBlockHeight;
     nsRect  childBounds;
@@ -2168,7 +2183,8 @@ nsBlockFrame::ReflowDirtyLines(nsBlockReflowState& aState)
 
     // If we're supposed to update our maximum width, then we'll also need to
     // reflow this line if it's line wrapped and any of the continuing lines
-    // are dirty. If we are printing (constrained height), always reflow the line
+    // are dirty.  If we are printing (constrained height), always reflow
+    // the line.
     if ((NS_UNCONSTRAINEDSIZE != aState.mReflowState.availableHeight) ||
         (!line->IsDirty() &&
          aState.GetFlag(BRS_COMPUTEMAXWIDTH) &&

layout/generic/nsInlineFrame.cpp

@@ -45,6 +45,7 @@
 #include "nsIFontMetrics.h"
 #include "nsAbsoluteContainingBlock.h"
 #include "nsLayoutAtoms.h"
+#include "nsReflowPath.h"
 
 #ifdef DEBUG
 #undef NOISY_PUSHING
@@ -1204,8 +1205,12 @@ nsPositionedInlineFrame::Reflow(nsIPresContext*          aPresContext,
 {
   nsresult  rv = NS_OK;
 
-  // See if it's an incremental reflow command
+  nsRect oldRect(mRect);
-  if (eReflowReason_Incremental == aReflowState.reason) {
+
+  // See if it's an incremental reflow command and we're not the target
+  if (mAbsoluteContainer.HasAbsoluteFrames() &&
+      eReflowReason_Incremental == aReflowState.reason &&
+      !aReflowState.path->mReflowCommand) {
     // Give the absolute positioning code a chance to handle it
     PRBool  handled;
     nsRect  childBounds;
@@ -1252,7 +1257,18 @@ nsPositionedInlineFrame::Reflow(nsIPresContext*          aPresContext,
 
   // Let the absolutely positioned container reflow any absolutely positioned
   // child frames that need to be reflowed
-  if (NS_SUCCEEDED(rv)) {
+  // We want to do this under either of two conditions:
+  //  1. If we didn't do the incremental reflow above.
+  //  2. If our size changed.
+  // Even though it's the padding edge that's the containing block, we
+  // can use our rect (the border edge) since if the border style
+  // changed, the reflow would have been targeted at us so we'd satisfy
+  // condition 1.
+  if (NS_SUCCEEDED(rv) &&
+      mAbsoluteContainer.HasAbsoluteFrames() &&
+      (eReflowReason_Incremental != aReflowState.reason ||
+       aReflowState.path->mReflowCommand ||
+       mRect != oldRect)) {
     nscoord containingBlockWidth = -1;
     nscoord containingBlockHeight = -1;
     nsRect  childBounds;

layout/html/base/src/nsAbsoluteContainingBlock.cpp

@@ -194,8 +194,11 @@ nsAbsoluteContainingBlock::Reflow(nsIFrame*                aDelegatingFrame,
   // Initialize OUT parameter
   aChildBounds.SetRect(0, 0, 0, 0);
 
-  // Make a copy of the reflow state. If the reason is eReflowReason_Incremental,
+  // Make a copy of the reflow state.  If the reason is
-  // then change it to eReflowReason_Resize
+  // eReflowReason_Incremental (which should mean either that the target
+  // is the frame for which this is the absolute container or that the
+  // container changed size due to incremental reflow of its children),
+  // then change it to eReflowReason_Resize.
   nsHTMLReflowState reflowState(aReflowState);
   if (eReflowReason_Incremental == reflowState.reason) {
     reflowState.reason = eReflowReason_Resize;

layout/html/base/src/nsBlockFrame.cpp

@@ -729,6 +729,8 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
   }
 #endif
 
+  nsRect oldRect(mRect);
+
   // Should we create a space manager?
   nsAutoSpaceManager autoSpaceManager(NS_CONST_CAST(nsHTMLReflowState &, aReflowState));
 
@@ -739,8 +741,10 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
   if (NS_BLOCK_SPACE_MGR & mState)
     autoSpaceManager.CreateSpaceManagerFor(aPresContext, this);
 
-  // See if it's an incremental reflow command
+  // See if it's an incremental reflow command and we're not the target
-  if (eReflowReason_Incremental == aReflowState.reason) {
+  if (mAbsoluteContainer.HasAbsoluteFrames() &&
+      eReflowReason_Incremental == aReflowState.reason &&
+      !aReflowState.path->mReflowCommand) {
     // Give the absolute positioning code a chance to handle it
     nscoord containingBlockWidth;
     nscoord containingBlockHeight;
@@ -1021,7 +1025,18 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
   // Let the absolutely positioned container reflow any absolutely positioned
   // child frames that need to be reflowed, e.g., elements with a percentage
   // based width/height
-  if (NS_SUCCEEDED(rv) && mAbsoluteContainer.HasAbsoluteFrames()) {
+  // We want to do this under either of two conditions:
+  //  1. If we didn't do the incremental reflow above.
+  //  2. If our size changed.
+  // Even though it's the padding edge that's the containing block, we
+  // can use our rect (the border edge) since if the border style
+  // changed, the reflow would have been targeted at us so we'd satisfy
+  // condition 1.
+  if (NS_SUCCEEDED(rv) &&
+      mAbsoluteContainer.HasAbsoluteFrames() &&
+      (eReflowReason_Incremental != aReflowState.reason ||
+       aReflowState.path->mReflowCommand ||
+       mRect != oldRect)) {
     nscoord containingBlockWidth;
     nscoord containingBlockHeight;
     nsRect  childBounds;
@@ -2168,7 +2183,8 @@ nsBlockFrame::ReflowDirtyLines(nsBlockReflowState& aState)
 
     // If we're supposed to update our maximum width, then we'll also need to
     // reflow this line if it's line wrapped and any of the continuing lines
-    // are dirty. If we are printing (constrained height), always reflow the line
+    // are dirty.  If we are printing (constrained height), always reflow
+    // the line.
     if ((NS_UNCONSTRAINEDSIZE != aState.mReflowState.availableHeight) ||
         (!line->IsDirty() &&
          aState.GetFlag(BRS_COMPUTEMAXWIDTH) &&

layout/html/base/src/nsInlineFrame.cpp

@@ -45,6 +45,7 @@
 #include "nsIFontMetrics.h"
 #include "nsAbsoluteContainingBlock.h"
 #include "nsLayoutAtoms.h"
+#include "nsReflowPath.h"
 
 #ifdef DEBUG
 #undef NOISY_PUSHING
@@ -1204,8 +1205,12 @@ nsPositionedInlineFrame::Reflow(nsIPresContext*          aPresContext,
 {
   nsresult  rv = NS_OK;
 
-  // See if it's an incremental reflow command
+  nsRect oldRect(mRect);
-  if (eReflowReason_Incremental == aReflowState.reason) {
+
+  // See if it's an incremental reflow command and we're not the target
+  if (mAbsoluteContainer.HasAbsoluteFrames() &&
+      eReflowReason_Incremental == aReflowState.reason &&
+      !aReflowState.path->mReflowCommand) {
     // Give the absolute positioning code a chance to handle it
     PRBool  handled;
     nsRect  childBounds;
@@ -1252,7 +1257,18 @@ nsPositionedInlineFrame::Reflow(nsIPresContext*          aPresContext,
 
   // Let the absolutely positioned container reflow any absolutely positioned
   // child frames that need to be reflowed
-  if (NS_SUCCEEDED(rv)) {
+  // We want to do this under either of two conditions:
+  //  1. If we didn't do the incremental reflow above.
+  //  2. If our size changed.
+  // Even though it's the padding edge that's the containing block, we
+  // can use our rect (the border edge) since if the border style
+  // changed, the reflow would have been targeted at us so we'd satisfy
+  // condition 1.
+  if (NS_SUCCEEDED(rv) &&
+      mAbsoluteContainer.HasAbsoluteFrames() &&
+      (eReflowReason_Incremental != aReflowState.reason ||
+       aReflowState.path->mReflowCommand ||
+       mRect != oldRect)) {
     nscoord containingBlockWidth = -1;
     nscoord containingBlockHeight = -1;
     nsRect  childBounds;