From db184f49e1044f8f1e6776acf34dd08df4df6c6e Mon Sep 17 00:00:00 2001
From: Mats Palmgren <matspal@gmail.com>
Date: Sat, 23 Feb 2013 11:38:15 +0100
Subject: [PATCH] Bug 843931 - Make nsLineLayout::NewPerFrameData() allocation
 infallible.  r=roc

---
 layout/generic/nsLineLayout.cpp | 60 ++++++++++++++-------------------
 layout/generic/nsLineLayout.h   |  8 +++--
 2 files changed, 30 insertions(+), 38 deletions(-)

diff --git a/layout/generic/nsLineLayout.cpp b/layout/generic/nsLineLayout.cpp
index 485f2daf5a3b..4c9d36f7de58 100644
--- a/layout/generic/nsLineLayout.cpp
+++ b/layout/generic/nsLineLayout.cpp
@@ -572,15 +572,15 @@ nsLineLayout::IsZeroHeight()
   return true;
 }
 
-nsresult
-nsLineLayout::NewPerFrameData(PerFrameData** aResult)
+nsLineLayout::PerFrameData*
+nsLineLayout::NewPerFrameData()
 {
   PerFrameData* pfd = mFrameFreeList;
-  if (nullptr == pfd) {
+  if (!pfd) {
     void *mem;
     PL_ARENA_ALLOCATE(mem, &mArena, sizeof(PerFrameData));
-    if (nullptr == mem) {
-      return NS_ERROR_OUT_OF_MEMORY;
+    if (!mem) {
+      NS_RUNTIMEABORT("OOM");
     }
     pfd = reinterpret_cast<PerFrameData*>(mem);
   }
@@ -597,8 +597,7 @@ nsLineLayout::NewPerFrameData(PerFrameData** aResult)
   pfd->mVerticalAlign = 0xFF;
   mFramesAllocated++;
 #endif
-  *aResult = pfd;
-  return NS_OK;
+  return pfd;
 }
 
 bool
@@ -709,11 +708,7 @@ nsLineLayout::ReflowFrame(nsIFrame* aFrame,
   // Initialize OUT parameter
   aPushedFrame = false;
 
-  PerFrameData* pfd;
-  nsresult rv = NewPerFrameData(&pfd);
-  if (NS_FAILED(rv)) {
-    return rv;
-  }
+  PerFrameData* pfd = NewPerFrameData();
   PerSpanData* psd = mCurrentSpan;
   psd->AppendFrame(pfd);
 
@@ -830,8 +825,8 @@ nsLineLayout::ReflowFrame(nsIFrame* aFrame,
                                  &savedOptionalBreakPriority);
 
   if (!isText) {
-    rv = aFrame->Reflow(mPresContext, metrics, reflowStateHolder.ref(),
-                        aReflowStatus);
+    nsresult rv = aFrame->Reflow(mPresContext, metrics, reflowStateHolder.ref(),
+                                 aReflowStatus);
     if (NS_FAILED(rv)) {
       NS_WARNING( "Reflow of frame failed in nsLineLayout" );
       return rv;
@@ -1054,7 +1049,7 @@ nsLineLayout::ReflowFrame(nsIFrame* aFrame,
   printf(" status=%x\n", aReflowStatus);
 #endif
 
-  return rv;
+  return NS_OK;
 }
 
 void
@@ -1315,14 +1310,13 @@ nsLineLayout::PlaceFrame(PerFrameData* pfd, nsHTMLReflowMetrics& aMetrics)
   }
 }
 
-nsresult
+void
 nsLineLayout::AddBulletFrame(nsIFrame* aFrame,
                              const nsHTMLReflowMetrics& aMetrics)
 {
   NS_ASSERTION(mCurrentSpan == mRootSpan, "bad linelayout user");
   NS_ASSERTION(mGotLineBox, "must have line box");
 
-
   nsIFrame *blockFrame = mBlockReflowState->frame;
   NS_ASSERTION(blockFrame->IsFrameOfType(nsIFrame::eBlockFrame),
                "must be for block");
@@ -1331,25 +1325,21 @@ nsLineLayout::AddBulletFrame(nsIFrame* aFrame,
     mLineBox->SetHasBullet();
   }
 
-  PerFrameData* pfd;
-  nsresult rv = NewPerFrameData(&pfd);
-  if (NS_SUCCEEDED(rv)) {
-    mRootSpan->AppendFrame(pfd);
-    pfd->mFrame = aFrame;
-    pfd->mMargin.SizeTo(0, 0, 0, 0);
-    pfd->mBorderPadding.SizeTo(0, 0, 0, 0);
-    pfd->mFlags = 0;  // all flags default to false
-    pfd->SetFlag(PFD_ISBULLET, true);
-    if (aMetrics.ascent == nsHTMLReflowMetrics::ASK_FOR_BASELINE)
-      pfd->mAscent = aFrame->GetBaseline();
-    else
-      pfd->mAscent = aMetrics.ascent;
+  PerFrameData* pfd = NewPerFrameData();
+  mRootSpan->AppendFrame(pfd);
+  pfd->mFrame = aFrame;
+  pfd->mMargin.SizeTo(0, 0, 0, 0);
+  pfd->mBorderPadding.SizeTo(0, 0, 0, 0);
+  pfd->mFlags = 0;  // all flags default to false
+  pfd->SetFlag(PFD_ISBULLET, true);
+  if (aMetrics.ascent == nsHTMLReflowMetrics::ASK_FOR_BASELINE)
+    pfd->mAscent = aFrame->GetBaseline();
+  else
+    pfd->mAscent = aMetrics.ascent;
 
-    // Note: y value will be updated during vertical alignment
-    pfd->mBounds = aFrame->GetRect();
-    pfd->mOverflowAreas = aMetrics.mOverflowAreas;
-  }
-  return rv;
+  // Note: y value will be updated during vertical alignment
+  pfd->mBounds = aFrame->GetRect();
+  pfd->mOverflowAreas = aMetrics.mOverflowAreas;
 }
 
 #ifdef DEBUG
diff --git a/layout/generic/nsLineLayout.h b/layout/generic/nsLineLayout.h
index 7d3eb1facd16..27bbeac619f8 100644
--- a/layout/generic/nsLineLayout.h
+++ b/layout/generic/nsLineLayout.h
@@ -87,8 +87,7 @@ public:
                        nsHTMLReflowMetrics* aMetrics,
                        bool& aPushedFrame);
 
-  nsresult AddBulletFrame(nsIFrame* aFrame,
-                          const nsHTMLReflowMetrics& aMetrics);
+  void AddBulletFrame(nsIFrame* aFrame, const nsHTMLReflowMetrics& aMetrics);
 
   void RemoveBulletFrame(nsIFrame* aFrame) {
     PushFrame(aFrame);
@@ -504,7 +503,10 @@ protected:
 #endif
   PLArenaPool mArena; // Per span and per frame data, 4 byte aligned
 
-  nsresult NewPerFrameData(PerFrameData** aResult);
+  /**
+   * Allocate a PerFrameData from the mArena pool. The allocation is infallible.
+   */
+  PerFrameData* NewPerFrameData();
 
   /**
    * Allocate a PerSpanData from the mArena pool. The allocation is infallible.