Ensure we use the current locale when looking up fallback fonts per character

src/ports/SkFontConfigInterface_android.cpp

Index: src/ports/SkFontConfigInterface_android.cpp
diff --git a/src/ports/SkFontConfigInterface_android.cpp b/src/ports/SkFontConfigInterface_android.cpp
index 2e2d88d689bbdfaf80cb4d6e221ac5ab291012e5..206f194477689cbeda3fe09cfaad2d6a423ae713 100644
--- a/src/ports/SkFontConfigInterface_android.cpp
+++ b/src/ports/SkFontConfigInterface_android.cpp
@@ -107,6 +107,7 @@ public:
 private:
     void addFallbackFont(FontRecID fontRecID);
     SkTypeface* getTypefaceForFontRec(FontRecID fontRecID);
+    FallbackFontList* getCurrentLocaleFallbackFontList();
     FallbackFontList* findFallbackFontList(const SkLanguage& lang, bool isOriginal = true);
 
     SkTArray<FontRec> fFonts;
@@ -118,6 +119,11 @@ private:
     SkTDict<FallbackFontList*> fFallbackFontDict;
     SkTDict<FallbackFontList*> fFallbackFontAliasDict;
     FallbackFontList fDefaultFallbackList;
+
+    // fallback info for current locale
+    SkMutex fLocaleMutex;
+    SkString fCachedLocale;
+    FallbackFontList* fLocaleFallbackFontList;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -193,7 +199,8 @@ SkFontConfigInterfaceAndroid::SkFontConfigInterfaceAndroid(SkTDArray<FontFamily*
         fFamilyNameDict(1024),
         fDefaultFamilyRecID(INVALID_FAMILY_REC_ID),
         fFallbackFontDict(128),
-        fFallbackFontAliasDict(128) {
+        fFallbackFontAliasDict(128),
+        fLocaleFallbackFontList(NULL) {
 
     for (int i = 0; i < fontFamilies.count(); ++i) {
         FontFamily* family = fontFamilies[i];
@@ -489,8 +496,9 @@ SkTypeface* SkFontConfigInterfaceAndroid::getTypefaceForFontRec(FontRecID fontRe
 }
 
 bool SkFontConfigInterfaceAndroid::getFallbackFamilyNameForChar(SkUnichar uni, SkString* name) {
-    for (int i = 0; i < fDefaultFallbackList.count(); i++) {
-        FontRecID fontRecID = fDefaultFallbackList[i];
+    FallbackFontList* fallbackFontList = this->getCurrentLocaleFallbackFontList();
+    for (int i = 0; i < fallbackFontList->count(); i++) {
+        FontRecID fontRecID = fallbackFontList->getAt(i);
         SkTypeface* face = this->getTypefaceForFontRec(fontRecID);
 
         SkPaint paint;
@@ -533,6 +541,18 @@ SkTypeface* SkFontConfigInterfaceAndroid::getTypefaceForChar(SkUnichar uni,
     return NULL;
 }
 
+FallbackFontList* SkFontConfigInterfaceAndroid::getCurrentLocaleFallbackFontList() {
+    SkAutoMutexAcquire mutex(&fLocaleMutex);
+
+    SkString locale = SkFontConfigParser::GetLocale();
+    if (NULL == fLocaleFallbackFontList || locale != fCachedLocale) {
+        fCachedLocale = locale;
+        fLocaleFallbackFontList = this->findFallbackFontList(locale);

[reed1, 2013/06/25 16:28:45]

Does this leak the old fontlist?

[djsollen, 2013/06/25 16:38:20]

The short answer is no.  The fallbackfontlist is part of the object and as such
this pointer is guaranteed to be valid as long as the object is valid.  The
actual cleanup of the list takes place in the object's destructor.

On 2013/06/25 16:28:45, reed1 wrote:

[reed1, 2013/06/25 16:48:24]

In line 550 we assign into fLocalFallbackFontList. What if it was not null?

+    }
+
+    return fLocaleFallbackFontList;

[reed1, 2013/06/25 16:28:45]

the caller can manipulate this object outside of the mutex...

[djsollen, 2013/06/25 16:38:20]

removed the mutex in the next patch set.

On 2013/06/25 16:28:45, reed1 wrote:

+}
+
 FallbackFontList* SkFontConfigInterfaceAndroid::findFallbackFontList(const SkLanguage& lang,
                                                                      bool isOriginal) {
     const SkString& langTag = lang.getTag();