[prelim] Additional renderer fontconfig support.

chrome/browser/renderer_host/render_sandbox_host_linux.cc

Index: chrome/browser/renderer_host/render_sandbox_host_linux.cc
diff --git a/chrome/browser/renderer_host/render_sandbox_host_linux.cc b/chrome/browser/renderer_host/render_sandbox_host_linux.cc
index 453f0c753dce0b4311f134c4ae449f8f9cf07192..b4bf0234b990c046994a5a3fc179384cd3531811 100644
--- a/chrome/browser/renderer_host/render_sandbox_host_linux.cc
+++ b/chrome/browser/renderer_host/render_sandbox_host_linux.cc
@@ -6,6 +6,7 @@
 
 #include <stdint.h>
 #include <unistd.h>
+#include <fcntl.h>
 #include <sys/uio.h>
 #include <sys/socket.h>
 #include <sys/poll.h>
@@ -28,6 +29,8 @@
 #include "SkFontHost_fontconfig_direct.h"
 #include "SkFontHost_fontconfig_ipc.h"
 
+#include <fontconfig/fontconfig.h>
+
 using WebKit::WebCString;
 using WebKit::WebFontInfo;
 using WebKit::WebUChar;
@@ -139,6 +142,8 @@ class SandboxIPCProcess  {
       HandleGetStyleForStrike(fd, pickle, iter, fds);
     } else if (kind == LinuxSandbox::METHOD_MAKE_SHARED_MEMORY_SEGMENT) {
       HandleMakeSharedMemorySegment(fd, pickle, iter, fds);
+    } else if (kind == LinuxSandbox::METHOD_MATCH_WITH_FALLBACK) {
+      HandleMatchWithFallback(fd, pickle, iter, fds);
     }
 
   error:
@@ -358,6 +363,248 @@ class SandboxIPCProcess  {
     SendRendererReply(fds, reply, shm_fd);
   }
 
+  void HandleMatchWithFallback(int fd, const Pickle& pickle, void* iter,
+                               std::vector<int>& fds) {
+    // Unlike the other calls, for which we are an indirection in front of
+    // WebKit or Skia, this call is always made via this sandbox helper
+    // process. Therefore the fontconfig code goes in here directly.
+
+    std::string family;
+    bool is_bold, is_italic;
+    uint32 microsoft_charset;
+
+    if (!pickle.ReadString(&iter, &family) ||
+        family.empty() ||
+        !pickle.ReadBool(&iter, &is_bold) ||
+        !pickle.ReadBool(&iter, &is_italic) ||
+        !pickle.ReadUInt32(&iter, &microsoft_charset)) {
+      return;
+    }
+
+    FcLangSet* langset = FcLangSetCreate();
+    MSCharSetToFontconfig(langset, microsoft_charset);
+
+    FcPattern* pattern = FcPatternCreate();
+    FcPatternAddString(pattern, FC_FAMILY, (FcChar8*) family.c_str());
+    if (is_bold)
+      FcPatternAddInteger(pattern, FC_WEIGHT, FC_WEIGHT_BOLD);
+    if (is_italic)
+      FcPatternAddInteger(pattern, FC_SLANT, FC_SLANT_ITALIC);
+    FcPatternAddLangSet(pattern, FC_LANG, langset);
+    FcPatternAddBool(pattern, FC_SCALABLE, FcTrue);
+    FcConfigSubstitute(NULL, pattern, FcMatchPattern);
+    FcDefaultSubstitute(pattern);
+
+    FcResult result;
+    FcFontSet* font_set = FcFontSort(0, pattern, 0, 0, &result);
+    int font_fd = -1;
+    int good_enough_index = -1;
+    bool good_enough_index_set = false;
+
+    if (font_set) {
+      for (int i = 0; i < font_set->nfont; ++i) {
+        FcPattern* current = font_set->fonts[i];
+
+        // Older versions of fontconfig have a bug where they cannot select
+        // only scalable fonts so we have to manually filter the results.
+        FcBool is_scalable;
+        if (FcPatternGetBool(current, FC_SCALABLE, 0,
+                             &is_scalable) != FcResultMatch ||
+            !is_scalable) {
+          continue;
+        }
+
+        FcChar8* c_filename;
+        if (FcPatternGetString(current, FC_FILE, 0, &c_filename) != FcResultMatch)
+          continue;
+
+        // We only want to return sfnt (TrueType) based fonts. We don't have a
+        // very good way of detecting this so we'll filter based on the
+        // filename.
+        bool is_sfnt = false;
+        static const char kSFNTExtensions[][5] = {
+          ".ttf", ".otc", ".TTF", ".ttc", ""
+        };
+        const size_t filename_len = strlen(reinterpret_cast<char*>(c_filename));
+        for (unsigned j = 0; ; j++) {
+          if (kSFNTExtensions[j][0] == 0) {
+            // None of the extensions matched.
+            break;
+          }
+          const size_t ext_len = strlen(kSFNTExtensions[j]);
+          if (filename_len > ext_len &&
+              memcmp(c_filename + filename_len - ext_len,
+                     kSFNTExtensions[j], ext_len) == 0) {
+            is_sfnt = true;
+            break;
+          }
+        }
+
+        if (!is_sfnt)
+          continue;
+
+        // This font is good enough to pass muster, but we might be able to do
+        // better with subsequent ones.
+        if (!good_enough_index_set) {
+          good_enough_index = i;
+          good_enough_index_set = true;
+        }
+
+        FcValue matrix;
+        bool have_matrix = FcPatternGet(current, FC_MATRIX, 0, &matrix) == 0;
+
+        if (is_italic && have_matrix) {
+          // we asked for an italic font, but fontconfig is giving us a
+          // non-italic font with a transformation matrix.
+          continue;
+        }
+
+        FcValue embolden;
+        const bool have_embolden =
+            FcPatternGet(current, FC_EMBOLDEN, 0, &embolden) == 0;
+
+        if (is_bold && have_embolden) {
+          // we asked for a bold font, but fontconfig gave us a non-bold font
+          // and asked us to apply fake bolding.
+          continue;
+        }
+
+        font_fd = open(reinterpret_cast<char*>(c_filename), O_RDONLY);
+        if (font_fd >= 0)
+          break;
+      }
+    }
+
+    if (font_fd == -1 && good_enough_index_set) {
+      // We didn't find a font that we liked, so we fallback to something
+      // acceptable.
+      FcPattern* current = font_set->fonts[good_enough_index];
+      FcChar8* c_filename;
+      FcPatternGetString(current, FC_FILE, 0, &c_filename);
+      font_fd = open(reinterpret_cast<char*>(c_filename), O_RDONLY);
+    }
+
+    if (font_set)
+      FcFontSetDestroy(font_set);
+    FcPatternDestroy(pattern);
+
+    Pickle reply;
+    SendRendererReply(fds, reply, font_fd);
+
+    if (font_fd >= 0)
+      HANDLE_EINTR(close(font_fd));
+  }
+
+  // MSCharSetToFontconfig translates a Microsoft fdwCharSet value into a
+  // fontconfig language set by appending to |langset|.
+  static void MSCharSetToFontconfig(FcLangSet* langset, unsigned fdwCharSet) {
+    // We have need to translate raw fdwCharSet values into terms that fontconfig
+    // can understand. (See the description of fdwCharSet in the MSDN
+    // documentation for CreateFont:
+    // http://msdn.microsoft.com/en-us/library/dd183499(VS.85).aspx )
+    //
+    // Although the argument is /called/ 'charset', the actual values conflate
+    // character sets (which are sets of Unicode code points) and character
+    // encodings (which are algorithms for turning a series of bits into a
+    // series of code points.) Sometimes the values will name a language,
+    // sometimes they'll name an encoding. In the latter case I'm assuming that
+    // they mean the set of code points in the domain of that encoding.
+    //
+    // fontconfig deals with ISO 639-1 language codes:
+    //   http://en.wikipedia.org/wiki/List_of_ISO_639-1_codes
+    //
+    // So, for each of the documented fdwCharSet values I've had to take a
+    // guess at the set of ISO 639-1 languages intended.
+    //
+    // Firstly, we need to know the raw integer values for the Microsoft
+    // constants, which I'm taking from
+    // http://www.microsoft.com/mspress/books/sampchap/2344b.aspx
+
+    enum {
+      ANSI_CHARSET = 0,
+      DEFAULT_CHARSET = 1,
+      SYMBOL_CHARSET = 2,
+      MAC_CHARSET = 77,
+      SHIFTJIS_CHARSET = 128,
+      HANGUL_CHARSET = 129,
+      JOHAB_CHARSET = 130,
+      GB2312_CHARSET = 134,
+      CHINESEBIG5_CHARSET = 136,
+      GREEK_CHARSET = 161,
+      TURKISH_CHARSET = 162,
+      VIETNAMESE_CHARSET = 163,
+      HEBREW_CHARSET = 177,
+      ARABIC_CHARSET = 178,
+      BALTIC_CHARSET = 186,
+      RUSSIAN_CHARSET = 204,
+      THAI_CHARSET = 222,
+      EASTEUROPE_CHARSET = 238,
+      OEM_CHARSET = 255,
+    };
+
+    switch (fdwCharSet) {
+      case ANSI_CHARSET:
+      // These values I don't really know what to do with, so I'm going to map
+      // them to English also.
+      case DEFAULT_CHARSET:
+      case MAC_CHARSET:
+      case OEM_CHARSET:
+      case SYMBOL_CHARSET:
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("en"));
+        break;
+      case BALTIC_CHARSET:
+        // The three baltic languages.
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("et"));
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("lv"));
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("lt"));
+        break;
+      case CHINESEBIG5_CHARSET:
+      case GB2312_CHARSET:
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("zh"));
+        break;
+      case EASTEUROPE_CHARSET:
+        // A scattering of eastern European languages.
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("pl"));
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("cs"));
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("sk"));
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("hu"));
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("hr"));
+      case GREEK_CHARSET:
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("el"));
+        break;
+      case HANGUL_CHARSET:
+      case JOHAB_CHARSET:
+        // Korean
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("ko"));
+        break;
+      case RUSSIAN_CHARSET:
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("ru"));
+        break;
+      case SHIFTJIS_CHARSET:
+        // Japanese
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("jp"));
+        break;
+      case TURKISH_CHARSET:
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("tr"));
+        break;
+      case VIETNAMESE_CHARSET:
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("vi"));
+        break;
+      case ARABIC_CHARSET:
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("ar"));
+        break;
+      case HEBREW_CHARSET:
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("he"));
+        break;
+      case THAI_CHARSET:
+        FcLangSetAdd(langset, reinterpret_cast<const FcChar8*>("th"));
+        break;
+      // default:
+      // Don't add any languages in that case that we don't recognise the
+      // constant.
+    }
+  }
+
   void SendRendererReply(const std::vector<int>& fds, const Pickle& reply,
                          int reply_fd) {
     struct msghdr msg;