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..5aa7e913a1fe2f016eca3a5b067883eb0dff7235 100644
--- a/pdf/pdfium/pdfium_engine.cc
+++ b/pdf/pdfium/pdfium_engine.cc
@@ -294,6 +294,7 @@ void DeleteFont(struct _FPDF_SYSFONTINFO*, void* font_id) {
   pp::Module::Get()->core()->ReleaseResource(res_id);
 }
 
+// Font loading doesn't work in the renderer sandbox in Linux.
 FPDF_SYSFONTINFO g_font_info = {
   1,
   0,
@@ -305,6 +306,90 @@ FPDF_SYSFONTINFO g_font_info = {
   0,
   DeleteFont
 };
+#else
+struct FPDF_SYSFONTINFO_WITHMETRICS : public FPDF_SYSFONTINFO {
+  FPDF_SYSFONTINFO_WITHMETRICS(FPDF_SYSFONTINFO* default_sysfontinfo) {

[Lei Zhang, 2016/11/08 19:16:10]

explicit

+    version = default_sysfontinfo->version;
+    default_sysfontinfo_ = default_sysfontinfo;
+  }
+
+  FPDF_SYSFONTINFO* default_sysfontinfo_;
+};
+
+void* MapFontWithMetrics(struct _FPDF_SYSFONTINFO* sysfontinfo,

[Lei Zhang, 2016/11/08 19:16:10]

Just FPDF_SYSFONTINFO*

[npm, 2016/11/08 19:54:36]

The "_" is used on the Linux overrides in this file, although I don't get
why (I assume it makes no difference).

+                         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(struct _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(struct _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(struct _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(struct _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(struct _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(struct _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(struct _FPDF_SYSFONTINFO* sysfontinfo) {
+  auto* fontinfo_with_metrics =
+      static_cast<FPDF_SYSFONTINFO_WITHMETRICS*>(sysfontinfo);
+  fontinfo_with_metrics->default_sysfontinfo_->Release(
+      fontinfo_with_metrics->default_sysfontinfo_);
+  delete fontinfo_with_metrics->default_sysfontinfo_;
+}
 #endif  // defined(OS_LINUX)
 
 PDFiumEngine* g_engine_for_unsupported = nullptr;
@@ -516,13 +601,32 @@ bool InitializeSDK() {
   config.m_v8EmbedderSlot = gin::kEmbedderPDFium;
   FPDF_InitLibraryWithConfig(&config);
 
-#if defined(OS_LINUX)
+#if !defined(OS_LINUX)
+  FPDF_SYSFONTINFO_WITHMETRICS* g_font_info =

[Lei Zhang, 2016/11/08 19:16:10]

not a global

[npm, 2016/11/08 19:54:36]

What do you mean? Declare pointer in namespace?

[Lei Zhang, 2016/11/08 19:58:31]

The variable is named g_foo, yet it is a local variable, not a global like the
Linux version.

+      new FPDF_SYSFONTINFO_WITHMETRICS(FPDF_GetDefaultSystemFontInfo());

[Lei Zhang, 2016/11/08 19:16:10]

Does this get freed or if it a one time leak?

[npm, 2016/11/08 19:54:36]

We FPDF_SetSystemFontInfo on it, and Release is called on
https://cs.chromium.org/chromium/src/third_party/pdfium/fpdfsdk/fpdf_sysfonti...

But that doesn't delete the struct itself? I might need to call some
struct deleter in ShutdownSDK.

+  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)

[Lei Zhang, 2016/11/08 19:16:10]

This is the only one you actual care about, right? Maybe grab the return value
from FPDF_GetDefaultSystemFontInfo(), check this first, and if it's nullptr,
then don't even bother with FPDF_SYSFONTINFO_WITHMETRICS? Or is it the case that
it's never nullptr?

[npm, 2016/11/08 19:54:36]

Actually, the default always gets assigned all of these functions, so I think
I can just remove all those ifs. But this is because I looked at our
internal code... current ifs are based on the documentation. WDYT?

[Lei Zhang, 2016/11/08 19:58:31]

I guess stick with it since we want to follow the documentation.

+    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
 
   FSDK_SetUnSpObjProcessHandler(&g_unsupported_info);
-
   return true;
 }