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 #include "gin/gin_export.h"
  10
  11 namespace gin {
  12
  13 // Dictionary is useful when writing bindings for a function that either
  14 // receives an arbitrary JavaScript object as an argument or returns an
  15 // arbitrary JavaScript object as a result. For example, Dictionary is useful
  16 // when you might use the |dictionary| type in WebIDL:
  17 //
  18 //   http://heycam.github.io/webidl/#idl-dictionaries
  19 //
  20 // WARNING: You cannot retain a Dictionary object in the heap. The underlying
  21 //          storage for Dictionary is tied to the closest enclosing
  22 //          v8::HandleScope. Generally speaking, you should store a Dictionary
  23 //          on the stack.
  24 //
  25 class GIN_EXPORT Dictionary {
  26  public:
  27   explicit Dictionary(v8::Isolate* isolate);
  28   Dictionary(v8::Isolate* isolate, v8::Local<v8::Object> object);
  29   ~Dictionary();
  30
  31   static Dictionary CreateEmpty(v8::Isolate* isolate);
  32
  33   template<typename T>
  34   bool Get(const std::string& key, T* out) {
  35     v8::Local<v8::Value> val;
  36     if (!object_->Get(isolate_->GetCurrentContext(), StringToV8(isolate_, key))
  37              .ToLocal(&val)) {
  38       return false;
  39     }
  40     return ConvertFromV8(isolate_, val, out);
  41   }
  42
  43   template<typename T>
  44   bool Set(const std::string& key, T val) {
  45     v8::Local<v8::Value> v8_value;
  46     if (!TryConvertToV8(isolate_, val, &v8_value))
  47       return false;
  48     v8::Maybe<bool> result =
  49         object_->Set(isolate_->GetCurrentContext(), StringToV8(isolate_, key),
  50                     v8_value);
  51     return !result.IsNothing() && result.FromJust();
  52   }
  53
  54   v8::Isolate* isolate() const { return isolate_; }
  55
  56  private:
  57   friend struct Converter<Dictionary>;
  58
  59   // TODO(aa): Remove this. Instead, get via FromV8(), Set(), and Get().
  60   v8::Isolate* isolate_;
  61   v8::Local<v8::Object> object_;
  62 };
  63
  64 template<>
  65 struct GIN_EXPORT Converter<Dictionary> {
  66   static v8::Local<v8::Value> ToV8(v8::Isolate* isolate,
  67                                     Dictionary val);
  68   static bool FromV8(v8::Isolate* isolate,
  69                      v8::Local<v8::Value> val,
  70                      Dictionary* out);
  71 };
  72
  73 }  // namespace gin
  74
  75 #endif  // GIN_DICTIONARY_H_