gin/dictionary.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef GIN_DICTIONARY_H_
   6 #define GIN_DICTIONARY_H_
   7
   8 #include "gin/converter.h"
   9
  10 namespace gin {
  11
  12 // Dictionary is useful when writing bindings for a function that either
  13 // receives an arbitrary JavaScript object as an argument or returns an
  14 // arbitrary JavaScript object as a result. For example, Dictionary is useful
  15 // when you might use the |dictionary| type in WebIDL:
  16 //
  17 //   http://heycam.github.io/webidl/#idl-dictionaries
  18 //
  19 // WARNING: You cannot retain a Dictionary object in the heap. The underlying
  20 //          storage for Dictionary is tied to the closest enclosing
  21 //          v8::HandleScope. Generally speaking, you should store a Dictionary
  22 //          on the stack.
  23 //
  24 class Dictionary {
  25  public:
  26   explicit Dictionary(v8::Isolate* isolate);
  27   Dictionary(v8::Isolate* isolate, v8::Handle<v8::Object> object);
  28   ~Dictionary();
  29
  30   static Dictionary CreateEmpty(v8::Isolate* isolate);
  31
  32   template<typename T>
  33   bool Get(const std::string& key, T* out) {
  34     v8::Handle<v8::Value> val = object_->Get(StringToV8(isolate_, key));
  35     return ConvertFromV8(isolate_, val, out);
  36   }
  37
  38   template<typename T>
  39   bool Set(const std::string& key, T val) {
  40     return object_->Set(StringToV8(isolate_, key), ConvertToV8(isolate_, val));
  41   }
  42
  43   v8::Isolate* isolate() const { return isolate_; }
  44
  45  private:
  46   friend struct Converter<Dictionary>;
  47
  48   // TODO(aa): Remove this. Instead, get via FromV8(), Set(), and Get().
  49   v8::Isolate* isolate_;
  50   v8::Handle<v8::Object> object_;
  51 };
  52
  53 template<>
  54 struct Converter<Dictionary> {
  55   static v8::Handle<v8::Value> ToV8(v8::Isolate* isolate,
  56                                     Dictionary val);
  57   static bool FromV8(v8::Isolate* isolate,
  58                      v8::Handle<v8::Value> val,
  59                      Dictionary* out);
  60 };
  61
  62 }  // namespace gin
  63
  64 #endif  // GIN_DICTIONARY_H_