Mutex protect SkFontMgr_DirectWrite cache.

SkFontMgr_DirectWrite is constant, except for its typeface cache.
Protect this cache in the face of multiple threads.

R=robertphillips@google.com

Review URL: https://codereview.chromium.org/26023002

git-svn-id: http://skia.googlecode.com/svn/trunk@11615 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 14 insertions, 2 deletions

diff --git a/src/ports/SkFontHost_win_dw.cpp b/src/ports/SkFontHost_win_dw.cpp
index cc9674e946..1ab0b7e92b 100644
--- a/src/ports/SkFontHost_win_dw.cpp
+++ b/src/ports/SkFontHost_win_dw.cpp
@@ -113,6 +113,18 @@ protected:
                                                unsigned styleBits) SK_OVERRIDE;
 
 private:
+    SkMutex fTFCacheMutex;
+    void Add(SkTypeface* face, SkTypeface::Style requestedStyle, bool strong) {
+        SkAutoMutexAcquire ama(fTFCacheMutex);
+        fTFCache.add(face, requestedStyle, strong);
+    }
+
+    SkTypeface* FindByProcAndRef(SkTypefaceCache::FindProc proc, void* ctx) {
+        SkAutoMutexAcquire ama(fTFCacheMutex);
+        SkTypeface* typeface = fTFCache.findByProcAndRef(proc, ctx);
+        return typeface;
+    }
+
     friend class SkFontStyleSet_DirectWrite;
     SkTScopedComPtr<IDWriteFontCollection> fFontCollection;
     SkSMallocWCHAR fLocaleName;
@@ -1710,12 +1722,12 @@ SkTypeface* SkFontMgr_DirectWrite::createTypefaceFromDWriteFont(
                                            IDWriteFontFamily* fontFamily,
                                            StreamFontFileLoader* fontFileLoader,
                                            IDWriteFontCollectionLoader* fontCollectionLoader) {
-    SkTypeface* face = fTFCache.findByProcAndRef(FindByDWriteFont, font);
+    SkTypeface* face = FindByProcAndRef(FindByDWriteFont, font);
     if (NULL == face) {
         face = DWriteFontTypeface::Create(fontFace, font, fontFamily,
                                           fontFileLoader, fontCollectionLoader);
         if (face) {
-            fTFCache.add(face, get_style(font), fontCollectionLoader != NULL);
+            Add(face, get_style(font), fontCollectionLoader != NULL);
         }
     }
     return face;