From 14ad02c6931d7a46585e118f25e491c392a84947 Mon Sep 17 00:00:00 2001
From: John Daggett <jdaggett@mozilla.com>
Date: Tue, 12 May 2015 17:44:13 +0900
Subject: [PATCH] Bug 1056479 p1a - use lang as part of pref font fallback.
 r=karlt

---
 gfx/thebes/gfxPlatform.cpp | 46 ++++++++++++++++++++++++++++++++++++++
 gfx/thebes/gfxPlatform.h   |  3 +++
 gfx/thebes/gfxTextRun.cpp  |  5 ++++-
 3 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/gfx/thebes/gfxPlatform.cpp b/gfx/thebes/gfxPlatform.cpp
index fbed4f16562..554b4d2c3c7 100644
--- a/gfx/thebes/gfxPlatform.cpp
+++ b/gfx/thebes/gfxPlatform.cpp
@@ -382,6 +382,39 @@ static const char *gPrefLangNames[] = {
     "x-unicode",
 };
 
+// this needs to match the list of pref font.default.xx entries listed in all.js!
+// the order *must* match the order in eFontPrefLang
+static nsIAtom* gPrefLangToLangGroups[] = {
+    nsGkAtoms::x_western,
+    nsGkAtoms::Japanese,
+    nsGkAtoms::Taiwanese,
+    nsGkAtoms::Chinese,
+    nsGkAtoms::HongKongChinese,
+    nsGkAtoms::ko,
+    nsGkAtoms::x_cyrillic,
+    nsGkAtoms::el,
+    nsGkAtoms::th,
+    nsGkAtoms::he,
+    nsGkAtoms::ar,
+    nsGkAtoms::x_devanagari,
+    nsGkAtoms::x_tamil,
+    nsGkAtoms::x_armn,
+    nsGkAtoms::x_beng,
+    nsGkAtoms::x_cans,
+    nsGkAtoms::x_ethi,
+    nsGkAtoms::x_geor,
+    nsGkAtoms::x_gujr,
+    nsGkAtoms::x_guru,
+    nsGkAtoms::x_khmr,
+    nsGkAtoms::x_mlym,
+    nsGkAtoms::x_orya,
+    nsGkAtoms::x_telu,
+    nsGkAtoms::x_knda,
+    nsGkAtoms::x_sinh,
+    nsGkAtoms::x_tibt,
+    nsGkAtoms::Unicode
+};
+
 gfxPlatform::gfxPlatform()
   : mTileWidth(-1)
   , mTileHeight(-1)
@@ -1474,6 +1507,19 @@ gfxPlatform::GetFontPrefLangFor(nsIAtom *aLang)
     return GetFontPrefLangFor(lang.get());
 }
 
+nsIAtom*
+gfxPlatform::GetLangGroupForPrefLang(eFontPrefLang aLang)
+{
+    // the special CJK set pref lang should be resolved into separate
+    // calls to individual CJK pref langs before getting here
+    NS_ASSERTION(aLang != eFontPrefLang_CJKSet, "unresolved CJK set pref lang");
+
+    if (uint32_t(aLang) < ArrayLength(gPrefLangToLangGroups)) {
+        return gPrefLangToLangGroups[uint32_t(aLang)];
+    }
+    return nsGkAtoms::Unicode;
+}
+
 const char*
 gfxPlatform::GetPrefLangName(eFontPrefLang aLang)
 {
diff --git a/gfx/thebes/gfxPlatform.h b/gfx/thebes/gfxPlatform.h
index 5068999b188..6e262c9f62c 100644
--- a/gfx/thebes/gfxPlatform.h
+++ b/gfx/thebes/gfxPlatform.h
@@ -470,6 +470,9 @@ public:
     // convert a lang group atom to enum constant
     static eFontPrefLang GetFontPrefLangFor(nsIAtom *aLang);
 
+    // convert an enum constant to a lang group atom
+    static nsIAtom* GetLangGroupForPrefLang(eFontPrefLang aLang);
+
     // convert a enum constant to lang group string (i.e. eFontPrefLang_ChineseTW ==> "zh-TW")
     static const char* GetPrefLangName(eFontPrefLang aLang);
    
diff --git a/gfx/thebes/gfxTextRun.cpp b/gfx/thebes/gfxTextRun.cpp
index 48c5510466c..62ffa1d58d9 100644
--- a/gfx/thebes/gfxTextRun.cpp
+++ b/gfx/thebes/gfxTextRun.cpp
@@ -3082,7 +3082,10 @@ struct PrefFontCallbackData {
     {
         PrefFontCallbackData *prefFontData = static_cast<PrefFontCallbackData*>(aClosure);
 
-        gfxFontFamily *family = gfxPlatformFontList::PlatformFontList()->FindFamily(aName);
+        // map pref lang to langGroup for language-sensitive lookups
+        nsIAtom* lang = gfxPlatform::GetLangGroupForPrefLang(aLang);
+        gfxFontFamily *family =
+            gfxPlatformFontList::PlatformFontList()->FindFamily(aName, lang);
         if (family) {
             prefFontData->mPrefFamilies.AppendElement(family);
         }