From e8ca3f4e21152867faf31368c8c661b3deeea22a Mon Sep 17 00:00:00 2001
From: "L. David Baron" <dbaron@dbaron.org>
Date: Thu, 5 Aug 2010 21:59:20 -0700
Subject: [PATCH] Add bit to lines indicating that they may have a placeholder
 for a float that was pushed to the next line (and bump the child count up to
 32 bits).  (Bug 563584, patch 24)  r=roc

---
 layout/generic/nsBlockFrame.cpp       |  5 +++--
 layout/generic/nsBlockReflowState.cpp |  6 +++++-
 layout/generic/nsBlockReflowState.h   |  3 ++-
 layout/generic/nsLineBox.h            | 23 +++++++++++++++++++----
 4 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
index 93ebd3b7b47c..a34a0a2a08c3 100644
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -2409,7 +2409,8 @@ nsBlockFrame::ReflowLine(nsBlockReflowState& aState,
   aState.mCurrentLine = aLine;
   aLine->ClearDirty();
   aLine->InvalidateCachedIsEmpty();
-  
+  aLine->ClearHadFloatPushed();
+
   // Now that we know what kind of line we have, reflow it
   if (aLine->IsBlock()) {
     nsRect oldBounds = aLine->mFirstChild->GetRect();
@@ -4213,7 +4214,7 @@ nsBlockFrame::PlaceLine(nsBlockReflowState& aState,
   if (aState.mBelowCurrentLineFloats.NotEmpty()) {
     // Reflow the below-current-line floats, which places on the line's
     // float list.
-    aState.PlaceBelowCurrentLineFloats(aState.mBelowCurrentLineFloats);
+    aState.PlaceBelowCurrentLineFloats(aState.mBelowCurrentLineFloats, aLine);
     aLine->AppendFloats(aState.mBelowCurrentLineFloats);
   }
 
diff --git a/layout/generic/nsBlockReflowState.cpp b/layout/generic/nsBlockReflowState.cpp
index 6cc54aea8019..cc5d9cf949c2 100644
--- a/layout/generic/nsBlockReflowState.cpp
+++ b/layout/generic/nsBlockReflowState.cpp
@@ -605,6 +605,8 @@ nsBlockReflowState::AddFloat(nsLineLayout*       aLineLayout,
       aLineLayout->UpdateBand(availSpace, aFloat);
       // Record this float in the current-line list
       mCurrentLineFloats.Append(mFloatCacheFreeList.Alloc(aFloat));
+    } else {
+      (*aLineLayout->GetLine())->SetHadFloatPushed();
     }
   }
   else {
@@ -956,7 +958,8 @@ nsBlockReflowState::PushFloatPastBreak(nsIFrame *aFloat)
  * Place below-current-line floats.
  */
 void
-nsBlockReflowState::PlaceBelowCurrentLineFloats(nsFloatCacheFreeList& aList)
+nsBlockReflowState::PlaceBelowCurrentLineFloats(nsFloatCacheFreeList& aList,
+                                                nsLineBox* aLine)
 {
   nsFloatCache* fc = aList.Head();
   while (fc) {
@@ -974,6 +977,7 @@ nsBlockReflowState::PlaceBelowCurrentLineFloats(nsFloatCacheFreeList& aList)
     if (!placed) {
       aList.Remove(fc);
       delete fc;
+      aLine->SetHadFloatPushed();
     }
     fc = next;
   }
diff --git a/layout/generic/nsBlockReflowState.h b/layout/generic/nsBlockReflowState.h
index 4e0fe97a81ae..44f3386aad45 100644
--- a/layout/generic/nsBlockReflowState.h
+++ b/layout/generic/nsBlockReflowState.h
@@ -115,7 +115,8 @@ public:
 private:
   void PushFloatPastBreak(nsIFrame* aFloat);
 public:
-  void PlaceBelowCurrentLineFloats(nsFloatCacheFreeList& aFloats);
+  void PlaceBelowCurrentLineFloats(nsFloatCacheFreeList& aFloats,
+                                   nsLineBox* aLine);
 
   // Returns the first coordinate >= aY that clears the
   // floats indicated by aBreakType and has enough width between floats
diff --git a/layout/generic/nsLineBox.h b/layout/generic/nsLineBox.h
index 98e0030ec667..32110e373ccc 100644
--- a/layout/generic/nsLineBox.h
+++ b/layout/generic/nsLineBox.h
@@ -174,7 +174,7 @@ protected:
 //----------------------------------------------------------------------
 
 #define LINE_MAX_BREAK_TYPE  ((1 << 4) - 1)
-#define LINE_MAX_CHILD_COUNT ((1 << 20) - 1)
+#define LINE_MAX_CHILD_COUNT PR_INT32_MAX
 
 #if NS_STYLE_CLEAR_LAST_VALUE > 15
 need to rearrange the mBits bitfield;
@@ -330,8 +330,19 @@ public:
   PRBool HasBullet() const {
     return mFlags.mHasBullet;
   }
-  
-  
+
+  // mHadFloatPushed bit
+  void SetHadFloatPushed() {
+    mFlags.mHadFloatPushed = PR_TRUE;
+  }
+  void ClearHadFloatPushed() {
+    mFlags.mHadFloatPushed = PR_FALSE;
+  }
+  PRBool HadFloatPushed() const {
+    return mFlags.mHadFloatPushed;
+  }
+
+
   // mChildCount value
   PRInt32 GetChildCount() const {
     return (PRInt32) mFlags.mChildCount;
@@ -501,9 +512,13 @@ public:
     // mHasBullet indicates that this is an inline line whose block's
     // bullet is adjacent to this line and non-empty.
     PRUint32 mHasBullet : 1;
+    // Indicates that this line *may* have a placeholder for a float
+    // that was pushed to a later column or page.
+    PRUint32 mHadFloatPushed : 1;
     PRUint32 mBreakType : 4;
 
-    PRUint32 mChildCount : 17;
+    // FIXME: Move this out of FlagBits
+    PRUint32 mChildCount;
   };
 
   struct ExtraData {