From dc7ba8870e6bbcf3e4c8fd79ff249116449fffbd Mon Sep 17 00:00:00 2001
From: "roc+%cs.cmu.edu" <roc+%cs.cmu.edu@18797224-902f-48f8-a5cc-f745e15eee43>
Date: Sun, 26 Aug 2007 23:44:00 +0000
Subject: [PATCH] Bug 390234. Coalesce glyph runs after sorting them, gets them
 into the canonical form. Also add debug code to help track down textrun-cache
 related crashers. r=vlad

git-svn-id: svn://10.0.0.236/trunk@233130 18797224-902f-48f8-a5cc-f745e15eee43
---
 mozilla/gfx/thebes/public/gfxFont.h           |  5 ++++
 mozilla/gfx/thebes/src/gfxFont.cpp            | 24 ++++++++++++++++++-
 .../gfx/thebes/src/gfxTextRunWordCache.cpp    | 18 +++++++++++++-
 3 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/mozilla/gfx/thebes/public/gfxFont.h b/mozilla/gfx/thebes/public/gfxFont.h
index 3cafe0d4824..d71ba6cd5b5 100644
--- a/mozilla/gfx/thebes/public/gfxFont.h
+++ b/mozilla/gfx/thebes/public/gfxFont.h
@@ -1113,6 +1113,11 @@ public:
         PRPackedBool mPartIsEndOfLigature;
     };
 
+#ifdef DEBUG
+    // number of entries referencing this textrun in the gfxTextRunWordCache
+    PRUint32 mCachedWords;
+#endif
+
 private:
     // **** general helpers **** 
 
diff --git a/mozilla/gfx/thebes/src/gfxFont.cpp b/mozilla/gfx/thebes/src/gfxFont.cpp
index 606c5d24e09..246572fb9fd 100644
--- a/mozilla/gfx/thebes/src/gfxFont.cpp
+++ b/mozilla/gfx/thebes/src/gfxFont.cpp
@@ -1489,8 +1489,23 @@ gfxTextRun::AddGlyphRun(gfxFont *aFont, PRUint32 aUTF16Offset, PRBool aForceNewR
 void
 gfxTextRun::SortGlyphRuns()
 {
+    if (mGlyphRuns.Length() <= 1)
+        return;
+
+    nsTArray<GlyphRun> runs(mGlyphRuns);
     GlyphRunOffsetComparator comp;
-    mGlyphRuns.Sort(comp);
+    runs.Sort(comp);
+
+    // Now copy back, coalescing adjacent glyph runs that have the same font
+    mGlyphRuns.Clear();
+    PRUint32 i;
+    for (i = 0; i < runs.Length(); ++i) {
+        // a GlyphRun with the same font as the previous GlyphRun can just
+        // be skipped; the last GlyphRun will cover its character range.
+        if (i == 0 || runs[i].mFont != runs[i - 1].mFont) {
+            mGlyphRuns.AppendElement(runs[i]);
+        }
+    }
 }
 
 PRUint32
@@ -1653,8 +1668,15 @@ gfxTextRun::CopyGlyphDataFrom(gfxTextRun *aSource, PRUint32 aStart,
     }
 
     GlyphRunIterator iter(aSource, aStart, aLength);
+#ifdef DEBUG
+    gfxFont *lastFont = nsnull;
+#endif
     while (iter.NextRun()) {
         gfxFont *font = iter.GetGlyphRun()->mFont;
+        NS_ASSERTION(font != lastFont, "Glyphruns not coalesced?");
+#ifdef DEBUG
+        lastFont = font;
+#endif
         PRUint32 start = iter.GetStringStart();
         PRUint32 end = iter.GetStringEnd();
         NS_ASSERTION(aSource->IsClusterStart(start),
diff --git a/mozilla/gfx/thebes/src/gfxTextRunWordCache.cpp b/mozilla/gfx/thebes/src/gfxTextRunWordCache.cpp
index 9786ef0f747..b5c49f062df 100644
--- a/mozilla/gfx/thebes/src/gfxTextRunWordCache.cpp
+++ b/mozilla/gfx/thebes/src/gfxTextRunWordCache.cpp
@@ -243,6 +243,9 @@ TextRunWordCache::LookupWord(gfxTextRun *aTextRun, gfxFont *aFirstFont,
     if (fontEntry->mTextRun) {
         existingEntry = fontEntry;
     } else {
+#ifdef DEBUG
+        ++aTextRun->mCachedWords;
+#endif
         PR_LOG(gWordCacheLog, PR_LOG_DEBUG, ("%p(%d-%d,%d): added using font", aTextRun, aStart, aEnd - aStart, aHash));
         key.mFontOrGroup = aTextRun->GetFontGroup();
         CacheHashEntry *groupEntry = mCache.GetEntry(key);
@@ -368,7 +371,10 @@ TextRunWordCache::MakeTextRun(const PRUnichar *aText, PRUint32 aLength,
     nsAutoPtr<gfxTextRun> textRun;
     textRun = new gfxTextRun(aParams, aText, aLength, aFontGroup, aFlags);
     if (!textRun || !textRun->GetCharacterGlyphs())
-        return nsnull;   
+        return nsnull;
+#ifdef DEBUG
+    textRun->mCachedWords = 0;
+#endif
 
     gfxFont *font = aFontGroup->GetFontAt(0);
     nsresult rv = textRun->AddGlyphRun(font, 0);
@@ -442,6 +448,9 @@ TextRunWordCache::MakeTextRun(const PRUint8 *aText, PRUint32 aLength,
     textRun = new gfxTextRun(aParams, aText, aLength, aFontGroup, aFlags);
     if (!textRun || !textRun->GetCharacterGlyphs())
         return nsnull;
+#ifdef DEBUG
+    textRun->mCachedWords = 0;
+#endif
 
     gfxFont *font = aFontGroup->GetFontAt(0);
     nsresult rv = textRun->AddGlyphRun(font, 0);
@@ -519,6 +528,9 @@ TextRunWordCache::RemoveWord(gfxTextRun *aTextRun, PRUint32 aStart,
         // XXX would like to use RawRemoveEntry here plus some extra method
         // that conditionally shrinks the hashtable
         mCache.RemoveEntry(key);
+#ifdef DEBUG
+        --aTextRun->mCachedWords;
+#endif
         PR_LOG(gWordCacheLog, PR_LOG_DEBUG, ("%p(%d-%d,%d): removed using %s",
             aTextRun, aStart, length, aHash,
             key.mFontOrGroup == aTextRun->GetFontGroup() ? "fontgroup" : "font"));
@@ -543,6 +555,10 @@ TextRunWordCache::RemoveTextRun(gfxTextRun *aTextRun)
         }
     }
     RemoveWord(aTextRun, wordStart, i, hash);
+#ifdef DEBUG
+    NS_ASSERTION(aTextRun->mCachedWords == 0,
+                 "Textrun was not completely removed from the cache!");
+#endif
 }
 
 static PRBool