Added a hack to only do incremental painting for the block whish is reflowing the html BODY; improved trace msgs; added code to collapse into nothingness empty blocks

layout/generic/nsBlockFrame.cpp

@@ -148,6 +148,7 @@ nsBlockReflowState::Initialize(nsIPresContext* aPresContext,
 
   mPrevPosBottomMargin = 0;
   mPrevNegBottomMargin = 0;
+  mPrevMarginSynthetic = PR_FALSE;
 
   mNextListOrdinal = -1;
 
@@ -672,7 +673,11 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
   // optimization cannot be done because this may be a nested block
   // that will be pushed to a new page by the containing block and the
   // nested block can't know that during its reflow.
+  // XXX and actually, this only always works for the block which is a
+  // child of the body.
   if (!aState.mPresContext->IsPaginated()) {
+    nsIAtom* tag = mContent->GetTag();
+    if (nsHTMLAtoms::body == tag) {
       nsIFrame* child = aLine->mFirstChild;
       for (PRInt32 i = aLine->mChildCount; --i >= 0; ) {
         nsFrameState state;
@@ -688,6 +693,8 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
         Invalidate(aLine->mBounds);
       }
     }
+    NS_IF_RELEASE(tag);
+  }
 
   // Consume space and advance running values
   aState.mY += aLine->mBounds.height;
@@ -1435,7 +1442,9 @@ nsBlockFrame::Reflow(nsIPresContext*      aPresContext,
     PostReflowCheck(aStatus);
   }
 #endif
-  NS_FRAME_TRACE_REFLOW_OUT("exit nsBlockFrame::Reflow", aStatus);
+  NS_FRAME_TRACE_MSG(
+    ("exit nsBlockFrame::Reflow: status=%d width=%d height=%d",
+     aStatus, aDesiredRect.width, aDesiredRect.height));
   return rv;
 }
 
@@ -1490,6 +1499,15 @@ void nsBlockFrame::ComputeDesiredRect(nsBlockReflowState& aState,
 {
   aDesiredRect.x = 0;
   aDesiredRect.y = 0;
+
+  // Special check for zero sized content: If our content is zero
+  // sized then we collapse into nothingness.
+  if ((0 == aState.mKidXMost - aState.mBorderPadding.left) &&
+      (0 == aState.mY - aState.mBorderPadding.top)) {
+    aDesiredRect.width = 0;
+    aDesiredRect.height = 0;
+  }
+  else {
     aDesiredRect.width = aState.mKidXMost + aState.mBorderPadding.right;
     if (!aState.mUnconstrainedWidth) {
       // Make sure we're at least as wide as the max size we were given
@@ -1529,6 +1547,7 @@ void nsBlockFrame::ComputeDesiredRect(nsBlockReflowState& aState,
       }
     }
   }
+}
 
 //----------------------------------------------------------------------
 

layout/generic/nsBlockReflowState.cpp

@@ -148,6 +148,7 @@ nsBlockReflowState::Initialize(nsIPresContext* aPresContext,
 
   mPrevPosBottomMargin = 0;
   mPrevNegBottomMargin = 0;
+  mPrevMarginSynthetic = PR_FALSE;
 
   mNextListOrdinal = -1;
 
@@ -672,7 +673,11 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
   // optimization cannot be done because this may be a nested block
   // that will be pushed to a new page by the containing block and the
   // nested block can't know that during its reflow.
+  // XXX and actually, this only always works for the block which is a
+  // child of the body.
   if (!aState.mPresContext->IsPaginated()) {
+    nsIAtom* tag = mContent->GetTag();
+    if (nsHTMLAtoms::body == tag) {
       nsIFrame* child = aLine->mFirstChild;
       for (PRInt32 i = aLine->mChildCount; --i >= 0; ) {
         nsFrameState state;
@@ -688,6 +693,8 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
         Invalidate(aLine->mBounds);
       }
     }
+    NS_IF_RELEASE(tag);
+  }
 
   // Consume space and advance running values
   aState.mY += aLine->mBounds.height;
@@ -1435,7 +1442,9 @@ nsBlockFrame::Reflow(nsIPresContext*      aPresContext,
     PostReflowCheck(aStatus);
   }
 #endif
-  NS_FRAME_TRACE_REFLOW_OUT("exit nsBlockFrame::Reflow", aStatus);
+  NS_FRAME_TRACE_MSG(
+    ("exit nsBlockFrame::Reflow: status=%d width=%d height=%d",
+     aStatus, aDesiredRect.width, aDesiredRect.height));
   return rv;
 }
 
@@ -1490,6 +1499,15 @@ void nsBlockFrame::ComputeDesiredRect(nsBlockReflowState& aState,
 {
   aDesiredRect.x = 0;
   aDesiredRect.y = 0;
+
+  // Special check for zero sized content: If our content is zero
+  // sized then we collapse into nothingness.
+  if ((0 == aState.mKidXMost - aState.mBorderPadding.left) &&
+      (0 == aState.mY - aState.mBorderPadding.top)) {
+    aDesiredRect.width = 0;
+    aDesiredRect.height = 0;
+  }
+  else {
     aDesiredRect.width = aState.mKidXMost + aState.mBorderPadding.right;
     if (!aState.mUnconstrainedWidth) {
       // Make sure we're at least as wide as the max size we were given
@@ -1529,6 +1547,7 @@ void nsBlockFrame::ComputeDesiredRect(nsBlockReflowState& aState,
       }
     }
   }
+}
 
 //----------------------------------------------------------------------
 

layout/generic/nsBlockReflowState.h

@@ -148,6 +148,7 @@ nsBlockReflowState::Initialize(nsIPresContext* aPresContext,
 
   mPrevPosBottomMargin = 0;
   mPrevNegBottomMargin = 0;
+  mPrevMarginSynthetic = PR_FALSE;
 
   mNextListOrdinal = -1;
 
@@ -672,7 +673,11 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
   // optimization cannot be done because this may be a nested block
   // that will be pushed to a new page by the containing block and the
   // nested block can't know that during its reflow.
+  // XXX and actually, this only always works for the block which is a
+  // child of the body.
   if (!aState.mPresContext->IsPaginated()) {
+    nsIAtom* tag = mContent->GetTag();
+    if (nsHTMLAtoms::body == tag) {
       nsIFrame* child = aLine->mFirstChild;
       for (PRInt32 i = aLine->mChildCount; --i >= 0; ) {
         nsFrameState state;
@@ -688,6 +693,8 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
         Invalidate(aLine->mBounds);
       }
     }
+    NS_IF_RELEASE(tag);
+  }
 
   // Consume space and advance running values
   aState.mY += aLine->mBounds.height;
@@ -1435,7 +1442,9 @@ nsBlockFrame::Reflow(nsIPresContext*      aPresContext,
     PostReflowCheck(aStatus);
   }
 #endif
-  NS_FRAME_TRACE_REFLOW_OUT("exit nsBlockFrame::Reflow", aStatus);
+  NS_FRAME_TRACE_MSG(
+    ("exit nsBlockFrame::Reflow: status=%d width=%d height=%d",
+     aStatus, aDesiredRect.width, aDesiredRect.height));
   return rv;
 }
 
@@ -1490,6 +1499,15 @@ void nsBlockFrame::ComputeDesiredRect(nsBlockReflowState& aState,
 {
   aDesiredRect.x = 0;
   aDesiredRect.y = 0;
+
+  // Special check for zero sized content: If our content is zero
+  // sized then we collapse into nothingness.
+  if ((0 == aState.mKidXMost - aState.mBorderPadding.left) &&
+      (0 == aState.mY - aState.mBorderPadding.top)) {
+    aDesiredRect.width = 0;
+    aDesiredRect.height = 0;
+  }
+  else {
     aDesiredRect.width = aState.mKidXMost + aState.mBorderPadding.right;
     if (!aState.mUnconstrainedWidth) {
       // Make sure we're at least as wide as the max size we were given
@@ -1529,6 +1547,7 @@ void nsBlockFrame::ComputeDesiredRect(nsBlockReflowState& aState,
       }
     }
   }
+}
 
 //----------------------------------------------------------------------
 

layout/html/base/src/nsBlockFrame.cpp

@@ -148,6 +148,7 @@ nsBlockReflowState::Initialize(nsIPresContext* aPresContext,
 
   mPrevPosBottomMargin = 0;
   mPrevNegBottomMargin = 0;
+  mPrevMarginSynthetic = PR_FALSE;
 
   mNextListOrdinal = -1;
 
@@ -672,7 +673,11 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
   // optimization cannot be done because this may be a nested block
   // that will be pushed to a new page by the containing block and the
   // nested block can't know that during its reflow.
+  // XXX and actually, this only always works for the block which is a
+  // child of the body.
   if (!aState.mPresContext->IsPaginated()) {
+    nsIAtom* tag = mContent->GetTag();
+    if (nsHTMLAtoms::body == tag) {
       nsIFrame* child = aLine->mFirstChild;
       for (PRInt32 i = aLine->mChildCount; --i >= 0; ) {
         nsFrameState state;
@@ -688,6 +693,8 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
         Invalidate(aLine->mBounds);
       }
     }
+    NS_IF_RELEASE(tag);
+  }
 
   // Consume space and advance running values
   aState.mY += aLine->mBounds.height;
@@ -1435,7 +1442,9 @@ nsBlockFrame::Reflow(nsIPresContext*      aPresContext,
     PostReflowCheck(aStatus);
   }
 #endif
-  NS_FRAME_TRACE_REFLOW_OUT("exit nsBlockFrame::Reflow", aStatus);
+  NS_FRAME_TRACE_MSG(
+    ("exit nsBlockFrame::Reflow: status=%d width=%d height=%d",
+     aStatus, aDesiredRect.width, aDesiredRect.height));
   return rv;
 }
 
@@ -1490,6 +1499,15 @@ void nsBlockFrame::ComputeDesiredRect(nsBlockReflowState& aState,
 {
   aDesiredRect.x = 0;
   aDesiredRect.y = 0;
+
+  // Special check for zero sized content: If our content is zero
+  // sized then we collapse into nothingness.
+  if ((0 == aState.mKidXMost - aState.mBorderPadding.left) &&
+      (0 == aState.mY - aState.mBorderPadding.top)) {
+    aDesiredRect.width = 0;
+    aDesiredRect.height = 0;
+  }
+  else {
     aDesiredRect.width = aState.mKidXMost + aState.mBorderPadding.right;
     if (!aState.mUnconstrainedWidth) {
       // Make sure we're at least as wide as the max size we were given
@@ -1529,6 +1547,7 @@ void nsBlockFrame::ComputeDesiredRect(nsBlockReflowState& aState,
       }
     }
   }
+}
 
 //----------------------------------------------------------------------
 

layout/html/base/src/nsBlockReflowState.cpp

@@ -148,6 +148,7 @@ nsBlockReflowState::Initialize(nsIPresContext* aPresContext,
 
   mPrevPosBottomMargin = 0;
   mPrevNegBottomMargin = 0;
+  mPrevMarginSynthetic = PR_FALSE;
 
   mNextListOrdinal = -1;
 
@@ -672,7 +673,11 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
   // optimization cannot be done because this may be a nested block
   // that will be pushed to a new page by the containing block and the
   // nested block can't know that during its reflow.
+  // XXX and actually, this only always works for the block which is a
+  // child of the body.
   if (!aState.mPresContext->IsPaginated()) {
+    nsIAtom* tag = mContent->GetTag();
+    if (nsHTMLAtoms::body == tag) {
       nsIFrame* child = aLine->mFirstChild;
       for (PRInt32 i = aLine->mChildCount; --i >= 0; ) {
         nsFrameState state;
@@ -688,6 +693,8 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
         Invalidate(aLine->mBounds);
       }
     }
+    NS_IF_RELEASE(tag);
+  }
 
   // Consume space and advance running values
   aState.mY += aLine->mBounds.height;
@@ -1435,7 +1442,9 @@ nsBlockFrame::Reflow(nsIPresContext*      aPresContext,
     PostReflowCheck(aStatus);
   }
 #endif
-  NS_FRAME_TRACE_REFLOW_OUT("exit nsBlockFrame::Reflow", aStatus);
+  NS_FRAME_TRACE_MSG(
+    ("exit nsBlockFrame::Reflow: status=%d width=%d height=%d",
+     aStatus, aDesiredRect.width, aDesiredRect.height));
   return rv;
 }
 
@@ -1490,6 +1499,15 @@ void nsBlockFrame::ComputeDesiredRect(nsBlockReflowState& aState,
 {
   aDesiredRect.x = 0;
   aDesiredRect.y = 0;
+
+  // Special check for zero sized content: If our content is zero
+  // sized then we collapse into nothingness.
+  if ((0 == aState.mKidXMost - aState.mBorderPadding.left) &&
+      (0 == aState.mY - aState.mBorderPadding.top)) {
+    aDesiredRect.width = 0;
+    aDesiredRect.height = 0;
+  }
+  else {
     aDesiredRect.width = aState.mKidXMost + aState.mBorderPadding.right;
     if (!aState.mUnconstrainedWidth) {
       // Make sure we're at least as wide as the max size we were given
@@ -1529,6 +1547,7 @@ void nsBlockFrame::ComputeDesiredRect(nsBlockReflowState& aState,
       }
     }
   }
+}
 
 //----------------------------------------------------------------------
 

layout/html/base/src/nsBlockReflowState.h

@@ -148,6 +148,7 @@ nsBlockReflowState::Initialize(nsIPresContext* aPresContext,
 
   mPrevPosBottomMargin = 0;
   mPrevNegBottomMargin = 0;
+  mPrevMarginSynthetic = PR_FALSE;
 
   mNextListOrdinal = -1;
 
@@ -672,7 +673,11 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
   // optimization cannot be done because this may be a nested block
   // that will be pushed to a new page by the containing block and the
   // nested block can't know that during its reflow.
+  // XXX and actually, this only always works for the block which is a
+  // child of the body.
   if (!aState.mPresContext->IsPaginated()) {
+    nsIAtom* tag = mContent->GetTag();
+    if (nsHTMLAtoms::body == tag) {
       nsIFrame* child = aLine->mFirstChild;
       for (PRInt32 i = aLine->mChildCount; --i >= 0; ) {
         nsFrameState state;
@@ -688,6 +693,8 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
         Invalidate(aLine->mBounds);
       }
     }
+    NS_IF_RELEASE(tag);
+  }
 
   // Consume space and advance running values
   aState.mY += aLine->mBounds.height;
@@ -1435,7 +1442,9 @@ nsBlockFrame::Reflow(nsIPresContext*      aPresContext,
     PostReflowCheck(aStatus);
   }
 #endif
-  NS_FRAME_TRACE_REFLOW_OUT("exit nsBlockFrame::Reflow", aStatus);
+  NS_FRAME_TRACE_MSG(
+    ("exit nsBlockFrame::Reflow: status=%d width=%d height=%d",
+     aStatus, aDesiredRect.width, aDesiredRect.height));
   return rv;
 }
 
@@ -1490,6 +1499,15 @@ void nsBlockFrame::ComputeDesiredRect(nsBlockReflowState& aState,
 {
   aDesiredRect.x = 0;
   aDesiredRect.y = 0;
+
+  // Special check for zero sized content: If our content is zero
+  // sized then we collapse into nothingness.
+  if ((0 == aState.mKidXMost - aState.mBorderPadding.left) &&
+      (0 == aState.mY - aState.mBorderPadding.top)) {
+    aDesiredRect.width = 0;
+    aDesiredRect.height = 0;
+  }
+  else {
     aDesiredRect.width = aState.mKidXMost + aState.mBorderPadding.right;
     if (!aState.mUnconstrainedWidth) {
       // Make sure we're at least as wide as the max size we were given
@@ -1529,6 +1547,7 @@ void nsBlockFrame::ComputeDesiredRect(nsBlockReflowState& aState,
       }
     }
   }
+}
 
 //----------------------------------------------------------------------