commit 358f93de3d16bd3fe5b0d043ea15b59ebc994e86
author drott <drott@chromium.org> Fri Aug 26 10:08:45 2016 -0700
committer Commit bot <commit-bot@chromium.org> Fri Aug 26 10:08:45 2016 -0700
tree d9b8dd7c431ac069aeda9869eff8322a4f27b691
parent 55713afb7a531bbb6a345a42b5a25ad709d8fd19

Restrict supported font formats in Chrome context

Chrome's complex text path uses HarfBuzz OpenType glyph lookup
functions. These do not support glyph lookup in Type 1 / Postscript
fonts and we do not wish to support those in Chrome any longer.

In order to avoid matching fonts against Type 1 fonts possible present
on Linux installations and exposed through fontconfig, this CL filters
those out in Skia's font matching code.

This change might not be desirable for all context in which Skia is
used, hence making it conditional on a Chrome context define.

BUG=skia:5685
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2280053002

Review-Url: https://codereview.chromium.org/2280053002

src/ports/SkFontConfigInterface_direct.cpp

diff --git a/src/ports/SkFontConfigInterface_direct.cpp b/src/ports/SkFontConfigInterface_direct.cpp
index 3455447..8fe9898 100644
--- a/src/ports/SkFontConfigInterface_direct.cpp
+++ b/src/ports/SkFontConfigInterface_direct.cpp
@@ -496,6 +496,10 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #define kMaxFontFamilyLength    2048
+#ifdef SK_FONT_CONFIG_INTERFACE_ONLY_ALLOW_SFNT_FONTS
+const char* kFontFormatTrueType = "TrueType";
+const char* kFontFormatCFF = "CFF";
+#endif
 
 SkFontConfigInterfaceDirect::SkFontConfigInterfaceDirect() {
     FCLocker lock;
@@ -524,6 +528,16 @@
     }
 #endif
 
+#ifdef SK_FONT_CONFIG_INTERFACE_ONLY_ALLOW_SFNT_FONTS
+    const char* font_format = get_name(pattern, FC_FONTFORMAT);
+    if (font_format
+        && strcmp(font_format, kFontFormatTrueType) != 0
+        && strcmp(font_format, kFontFormatCFF) != 0)
+    {
+        return false;
+    }
+#endif
+
     // fontconfig can also return fonts which are unreadable
     const char* c_filename = get_name(pattern, FC_FILE);
     if (!c_filename) {
@@ -593,6 +607,11 @@
 
     FcPatternAddBool(pattern, FC_SCALABLE, FcTrue);
 
+#ifdef SK_FONT_CONFIG_INTERFACE_ONLY_ALLOW_SFNT_FONTS
+    FcPatternAddString(pattern, FC_FONTFORMAT, reinterpret_cast<const FcChar8*>(kFontFormatTrueType));
+    FcPatternAddString(pattern, FC_FONTFORMAT, reinterpret_cast<const FcChar8*>(kFontFormatCFF));
+#endif
+
     FcConfigSubstitute(nullptr, pattern, FcMatchPattern);
     FcDefaultSubstitute(pattern);