Add Pepper TrueType font API call to enumerate fonts in a given family.

ppapi/cpp/dev/truetype_font_dev.h

Index: ppapi/cpp/dev/truetype_font_dev.h
diff --git a/ppapi/cpp/dev/truetype_font_dev.h b/ppapi/cpp/dev/truetype_font_dev.h
index a2c436943e70a53f7e7daef7384956223942395a..91f2f0eaef8ba04996591b86414eb0ca91af6601 100644
--- a/ppapi/cpp/dev/truetype_font_dev.h
+++ b/ppapi/cpp/dev/truetype_font_dev.h
@@ -27,14 +27,17 @@ class TrueTypeFontDesc_Dev {
   /// Default constructor for creating a <code>TrueTypeFontDesc_Dev</code>
   /// object.
   TrueTypeFontDesc_Dev();
+
   /// Constructor that takes an existing <code>PP_TrueTypeFontDesc_Dev</code>
   /// structure. The 'family' PP_Var field in the structure will be managed by
   /// this instance.
   TrueTypeFontDesc_Dev(PassRef, const PP_TrueTypeFontDesc_Dev& pp_desc);
+
   /// The copy constructor for <code>TrueTypeFontDesc_Dev</code>.
   ///
   /// @param[in] other A reference to a <code>TrueTypeFontDesc_Dev</code>.
   TrueTypeFontDesc_Dev(const TrueTypeFontDesc_Dev& other);
+
   ~TrueTypeFontDesc_Dev();
 
   TrueTypeFontDesc_Dev& operator=(const TrueTypeFontDesc_Dev& other);
@@ -81,8 +84,6 @@ class TrueTypeFontDesc_Dev {
   }
 
  private:
-  friend class TrueTypeFont_Dev;
-
   pp::Var family_;  // This manages the PP_Var embedded in desc_.
   PP_TrueTypeFontDesc_Dev desc_;
 };
@@ -127,6 +128,28 @@ class TrueTypeFont_Dev : public Resource {
       const InstanceHandle& instance,
       const CompletionCallbackWithOutput<std::vector<Var> >& cc);
 
+  /// Gets an array of TrueType font descriptors for a given font family. These
+  /// descriptors can be used to create a font in that family and matching the
+  /// descriptor attributes.
+  ///
+  /// @param[in] instance A <code>PP_Instance</code> requesting the font
+  /// descriptors.
+  /// @param[in] family A <code>Var</code> holding a string specifying the font
+  /// family.
+  /// @param[in] output A <code>PP_ArrayOutput</code> to hold the descriptors.
+  /// The output is an array of <code>TrueTypeFontDesc_Dev</code> structs. Each
+  /// desc contains a PP_Var for the family name which must be released.
+  /// @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
+  /// completion of GetFontsInFamily.

[dmichael (off chromium), 2013/04/12 23:34:18]

nit: Your params need to be updated for the C++ interface.

[bbudge, 2013/04/13 00:44:44]

Done.

+  ///
+  /// @return If >= 0, the number of font descriptors returned, otherwise an
+  /// error code from <code>pp_errors.h</code>.
+  static int32_t GetFontsInFamily(
+      const InstanceHandle& instance,
+      const Var& family,
+      const CompletionCallbackWithOutput<std::vector<TrueTypeFontDesc_Dev> >&
+          cc);
+
   /// Returns a description of the given font resource. This description may
   /// differ from the description passed to Create, reflecting the host's font
   /// matching and fallback algorithm.
@@ -192,6 +215,53 @@ struct CallbackOutputTraits<TrueTypeFontDesc_Dev> {
   }
 };
 
+class TrueTypeFontDescArrayOutputAdapterWithStorage
+    : public ArrayOutputAdapter<PP_TrueTypeFontDesc_Dev> {
+ public:
+  TrueTypeFontDescArrayOutputAdapterWithStorage() {
+    set_output(&temp_storage_);
+  };
+
+  virtual ~TrueTypeFontDescArrayOutputAdapterWithStorage() {
+    if (!temp_storage_.empty()) {
+      // An easy way to release the resource references held by |temp_storage_|.
+      output();
+    }
+  };
+
+  std::vector<TrueTypeFontDesc_Dev>& output() {
+    PP_DCHECK(output_storage_.empty());
+    typedef std::vector<PP_TrueTypeFontDesc_Dev> Entries;
+    for (Entries::iterator it = temp_storage_.begin();
+         it != temp_storage_.end(); ++it)
+      output_storage_.push_back(TrueTypeFontDesc_Dev(PASS_REF, *it));
+    temp_storage_.clear();
+    return output_storage_;
+  }
+
+ private:
+  std::vector<PP_TrueTypeFontDesc_Dev> temp_storage_;
+  std::vector<TrueTypeFontDesc_Dev> output_storage_;
+};
+
+// A specialization of CallbackOutputTraits to provide the callback system the
+// information on how to handle vectors of TrueTypeFontDesc_Dev. This converts
+// PP_TrueTypeFontDesc_Dev to TrueTypeFontDesc_Dev when passing to the plugin.
+template<>
+struct CallbackOutputTraits< std::vector<TrueTypeFontDesc_Dev> > {
+  typedef PP_ArrayOutput APIArgType;
+  typedef TrueTypeFontDescArrayOutputAdapterWithStorage StorageType;
+
+  static inline APIArgType StorageToAPIArg(StorageType& t) {
+    return t.pp_array_output();
+  }
+
+  static inline std::vector<TrueTypeFontDesc_Dev>& StorageToPluginArg(
+      StorageType& t) {
+    return t.output();
+  }
+};
+
 }  // namespace internal
 
 }  // namespace pp