Add font substituted metrics for OS other than Linux

pdf/pdfium/pdfium_engine.cc

Index: pdf/pdfium/pdfium_engine.cc
diff --git a/pdf/pdfium/pdfium_engine.cc b/pdf/pdfium/pdfium_engine.cc
index 475d56933053765ad2f460b8ca1d7a89df84a095..80365bf44d1a40e40342938c799bf7cf52b6a472 100644
--- a/pdf/pdfium/pdfium_engine.cc
+++ b/pdf/pdfium/pdfium_engine.cc
@@ -131,6 +131,7 @@ std::vector<uint32_t> GetPageNumbersFromPrintPageNumberRange(
 
 PP_Instance g_last_instance_id;
 
+// TODO(npm): Move font stuff to another file to reduce the size of this one
 PP_BrowserFont_Trusted_Weight WeightToBrowserFontTrustedWeight(int weight) {
   static_assert(PP_BROWSERFONT_TRUSTED_WEIGHT_100 == 0,
                 "PP_BrowserFont_Trusted_Weight min");
@@ -147,7 +148,7 @@ PP_BrowserFont_Trusted_Weight WeightToBrowserFontTrustedWeight(int weight) {
 // This list is for CPWL_FontMap::GetDefaultFontByCharset().
 // We pretend to have these font natively and let the browser (or underlying
 // fontconfig) to pick the proper font on the system.
-void EnumFonts(struct _FPDF_SYSFONTINFO* sysfontinfo, void* mapper) {
+void EnumFonts(FPDF_SYSFONTINFO* sysfontinfo, void* mapper) {
   FPDF_AddInstalledFont(mapper, "Arial", FXFONT_DEFAULT_CHARSET);
 
   const FPDF_CharsetFontMap* font_map = FPDF_GetDefaultTTFMap();
@@ -156,8 +157,13 @@ void EnumFonts(struct _FPDF_SYSFONTINFO* sysfontinfo, void* mapper) {
   }
 }
 
-void* MapFont(struct _FPDF_SYSFONTINFO*, int weight, int italic,
-              int charset, int pitch_family, const char* face, int* exact) {
+void* MapFont(FPDF_SYSFONTINFO*,
+              int weight,
+              int italic,
+              int charset,
+              int pitch_family,
+              const char* face,
+              int* exact) {
   // Do not attempt to map fonts if pepper is not initialized (for privet local
   // printing).
   // TODO(noamsml): Real font substitution (http://crbug.com/391978)
@@ -274,8 +280,10 @@ void* MapFont(struct _FPDF_SYSFONTINFO*, int weight, int italic,
   return reinterpret_cast<void*>(res_id);
 }
 
-unsigned long GetFontData(struct _FPDF_SYSFONTINFO*, void* font_id,
-                          unsigned int table, unsigned char* buffer,
+unsigned long GetFontData(FPDF_SYSFONTINFO*,
+                          void* font_id,
+                          unsigned int table,
+                          unsigned char* buffer,
                           unsigned long buf_size) {
   if (!pp::PDF::IsAvailable()) {
     NOTREACHED();
@@ -289,7 +297,7 @@ unsigned long GetFontData(struct _FPDF_SYSFONTINFO*, void* font_id,
   return size;
 }
 
-void DeleteFont(struct _FPDF_SYSFONTINFO*, void* font_id) {
+void DeleteFont(FPDF_SYSFONTINFO*, void* font_id) {
   long res_id = reinterpret_cast<long>(font_id);
   pp::Module::Get()->core()->ReleaseResource(res_id);
 }
@@ -305,6 +313,93 @@ FPDF_SYSFONTINFO g_font_info = {
   0,
   DeleteFont
 };
+#else
+struct FPDF_SYSFONTINFO_WITHMETRICS : public FPDF_SYSFONTINFO {
+  explicit FPDF_SYSFONTINFO_WITHMETRICS(FPDF_SYSFONTINFO* default_sysfontinfo) {
+    version = default_sysfontinfo->version;
+    default_sysfontinfo_ = default_sysfontinfo;
+  }
+
+  ~FPDF_SYSFONTINFO_WITHMETRICS() { delete default_sysfontinfo_; }

[Tom Sepez, 2016/11/08 21:25:52]

The public header says: 
Application should call FPDF_FreeMemory to free the returned ...

Unfortuntely, FPDF_FreeMemory doesn't exist.  

The delete here is wrong because the FPDF_SYSFONTINFO, being a C-style struct,
doesn't have a virtual destructor, and we're deleting it through a pointer to a
derived type.

I think we should add FPDF_FreeDefaultSystemFontInfo() to that API.
It can then static_cast it to FPDF_SYSINFO_DEFAULT, and then delete it because
the type will be correct.

[npm, 2016/11/08 21:56:26]

The Release() method deletes the extra stuff in FPDF_SYSFONTINFO_DEFAULT.
So the point of the delete here is to delete the FPDF_SYSFONTINFO part.
But that probably leaves holes compared to delete FPDF_SYSFONTINFO_DEFAULT
struct, correct? If that is the case, then I'll need to implement
that method.
Otherwise I don't see a way to delete it, since FPDF_SYSFONTINFO_DEFAULT
is not a known struct here.

+
+  FPDF_SYSFONTINFO* default_sysfontinfo_;
+};
+
+FPDF_SYSFONTINFO_WITHMETRICS* g_font_info = nullptr;
+
+void* MapFontWithMetrics(FPDF_SYSFONTINFO* sysfontinfo,
+                         int weight,
+                         int italic,
+                         int charset,
+                         int pitch_family,
+                         const char* face,
+                         int* exact) {
+  auto* fontinfo_with_metrics =
+      static_cast<FPDF_SYSFONTINFO_WITHMETRICS*>(sysfontinfo);
+  void* mapped_font = fontinfo_with_metrics->default_sysfontinfo_->MapFont(
+      fontinfo_with_metrics->default_sysfontinfo_, weight, italic, charset,
+      pitch_family, face, exact);
+  if (mapped_font && g_engine_for_fontmapper)
+    g_engine_for_fontmapper->FontSubstituted();
+  return mapped_font;
+}
+
+void DeleteFont(FPDF_SYSFONTINFO* sysfontinfo, void* font_id) {
+  auto* fontinfo_with_metrics =
+      static_cast<FPDF_SYSFONTINFO_WITHMETRICS*>(sysfontinfo);
+  fontinfo_with_metrics->default_sysfontinfo_->DeleteFont(
+      fontinfo_with_metrics->default_sysfontinfo_, font_id);
+}
+
+void EnumFonts(FPDF_SYSFONTINFO* sysfontinfo, void* mapper) {
+  auto* fontinfo_with_metrics =
+      static_cast<FPDF_SYSFONTINFO_WITHMETRICS*>(sysfontinfo);
+  fontinfo_with_metrics->default_sysfontinfo_->EnumFonts(
+      fontinfo_with_metrics->default_sysfontinfo_, mapper);
+}
+
+unsigned long GetFaceName(FPDF_SYSFONTINFO* sysfontinfo,
+                          void* hFont,
+                          char* buffer,
+                          unsigned long buffer_size) {
+  auto* fontinfo_with_metrics =
+      static_cast<FPDF_SYSFONTINFO_WITHMETRICS*>(sysfontinfo);
+  return fontinfo_with_metrics->default_sysfontinfo_->GetFaceName(
+      fontinfo_with_metrics->default_sysfontinfo_, hFont, buffer, buffer_size);
+}
+
+void* GetFont(FPDF_SYSFONTINFO* sysfontinfo, const char* face) {
+  auto* fontinfo_with_metrics =
+      static_cast<FPDF_SYSFONTINFO_WITHMETRICS*>(sysfontinfo);
+  return fontinfo_with_metrics->default_sysfontinfo_->GetFont(
+      fontinfo_with_metrics->default_sysfontinfo_, face);
+}
+
+int GetFontCharset(FPDF_SYSFONTINFO* sysfontinfo, void* hFont) {
+  auto* fontinfo_with_metrics =
+      static_cast<FPDF_SYSFONTINFO_WITHMETRICS*>(sysfontinfo);
+  return fontinfo_with_metrics->default_sysfontinfo_->GetFontCharset(
+      fontinfo_with_metrics->default_sysfontinfo_, hFont);
+}
+
+unsigned long GetFontData(FPDF_SYSFONTINFO* sysfontinfo,
+                          void* hFont,
+                          unsigned int table,
+                          unsigned char* buffer,
+                          unsigned long buf_size) {
+  auto* fontinfo_with_metrics =
+      static_cast<FPDF_SYSFONTINFO_WITHMETRICS*>(sysfontinfo);
+  return fontinfo_with_metrics->default_sysfontinfo_->GetFontData(
+      fontinfo_with_metrics->default_sysfontinfo_, hFont, table, buffer,
+      buf_size);
+}
+
+void Release(FPDF_SYSFONTINFO* sysfontinfo) {
+  auto* fontinfo_with_metrics =
+      static_cast<FPDF_SYSFONTINFO_WITHMETRICS*>(sysfontinfo);
+  fontinfo_with_metrics->default_sysfontinfo_->Release(
+      fontinfo_with_metrics->default_sysfontinfo_);
+}
 #endif  // defined(OS_LINUX)
 
 PDFiumEngine* g_engine_for_unsupported = nullptr;
@@ -516,7 +611,27 @@ bool InitializeSDK() {
   config.m_v8EmbedderSlot = gin::kEmbedderPDFium;
   FPDF_InitLibraryWithConfig(&config);
 
-#if defined(OS_LINUX)
+#if !defined(OS_LINUX)
+  g_font_info =
+      new FPDF_SYSFONTINFO_WITHMETRICS(FPDF_GetDefaultSystemFontInfo());
+  if (g_font_info->default_sysfontinfo_->Release)
+    g_font_info->Release = Release;
+  if (g_font_info->default_sysfontinfo_->EnumFonts)
+    g_font_info->EnumFonts = EnumFonts;
+  // Set new MapFont that calculates metrics
+  if (g_font_info->default_sysfontinfo_->MapFont)
+    g_font_info->MapFont = MapFontWithMetrics;
+  if (g_font_info->default_sysfontinfo_->GetFont)
+    g_font_info->GetFont = GetFont;
+  if (g_font_info->default_sysfontinfo_->GetFaceName)
+    g_font_info->GetFaceName = GetFaceName;
+  if (g_font_info->default_sysfontinfo_->GetFontCharset)
+    g_font_info->GetFontCharset = GetFontCharset;
+  // These are required according to documentation
+  g_font_info->GetFontData = GetFontData;
+  g_font_info->DeleteFont = DeleteFont;
+  FPDF_SetSystemFontInfo(g_font_info);
+#else
   // Font loading doesn't work in the renderer sandbox in Linux.
   FPDF_SetSystemFontInfo(&g_font_info);
 #endif
@@ -527,6 +642,9 @@ bool InitializeSDK() {
 }
 
 void ShutdownSDK() {
+#if !defined(OS_LINUX)
+  delete g_font_info;
+#endif
   FPDF_DestroyLibrary();
   TearDownV8();
 }