implement Serialize/Deserialize, so we can serialize pictures

skia/ext/SkFontHost_fontconfig.cpp

Index: skia/ext/SkFontHost_fontconfig.cpp
===================================================================
--- skia/ext/SkFontHost_fontconfig.cpp	(revision 150609)
+++ skia/ext/SkFontHost_fontconfig.cpp	(working copy)
@@ -31,6 +31,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
+#include "third_party/skia/src/ports/SkFontDescriptor.h"
 #include "SkFontHost.h"
 #include "SkStream.h"
 #include "SkFontHost_fontconfig_control.h"
@@ -210,19 +211,47 @@
     return NULL;
 }
 
-void SkFontHost::Serialize(const SkTypeface*, SkWStream*) {
-    SkASSERT(!"SkFontHost::Serialize unimplemented");
+uint32_t SkFontHost::NextLogicalFont(SkFontID curr, SkFontID orig) {
+    // We don't handle font fallback, WebKit does.
+    return 0;
 }
 
-SkTypeface* SkFontHost::Deserialize(SkStream* stream) {
-    SkASSERT(!"SkFontHost::Deserialize unimplemented");
-    return NULL;
+///////////////////////////////////////////////////////////////////////////////
+
+// Serialize, Deserialize need to be compatible across platforms, hence the use
+// of SkFontDescriptor.
+
+void SkFontHost::Serialize(const SkTypeface* face, SkWStream* stream) {
+    SkFontDescriptor desc(face->style());
+
+    std::string resolved_family_name;
+
+    const unsigned filefaceid = UniqueIdToFileFaceId(face->uniqueID());
+    if (GetFcImpl()->Match(&resolved_family_name, NULL,
+            true /* filefaceid valid */, filefaceid, "", NULL, 0, NULL, NULL))
+        desc.setFamilyName(resolved_family_name.c_str());
+    else
+        desc.setFamilyName("sans-serif");
+
+    // would also like other names (see SkFontDescriptor.h)
+
+    desc.serialize(stream);
+    
+    // by convention, we also write out the actual sfnt data, preceeded by
+    // a packed-length. For now we skip that, so we just write the zero.
+    stream->writePackedUInt(0);
 }
 
-// static
-uint32_t SkFontHost::NextLogicalFont(SkFontID curr, SkFontID orig) {
-    // We don't handle font fallback, WebKit does.
-    return 0;
+SkTypeface* SkFontHost::Deserialize(SkStream* stream) {
+    SkFontDescriptor desc(stream);
+
+    // by convention, Serialize will have also written the actual sfnt data.
+    // for now, we just want to skip it.
+    size_t size = stream->readPackedUInt();
+    stream->skip(size);
+
+    return SkFontHost::CreateTypeface(NULL, desc.getFamilyName(),
+                                      desc.getStyle());
 }
 
 ///////////////////////////////////////////////////////////////////////////////