gin/object_template_builder.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_OBJECT_TEMPLATE_BUILDER_H_
   6 #define GIN_OBJECT_TEMPLATE_BUILDER_H_
   7
   8 #include "base/bind.h"
   9 #include "base/callback.h"
  10 #include "base/strings/string_piece.h"
  11 #include "base/template_util.h"
  12 #include "gin/converter.h"
  13 #include "gin/function_template.h"
  14 #include "gin/gin_export.h"
  15 #include "v8/include/v8.h"
  16
  17 namespace gin {
  18
  19 namespace {
  20
  21 // Base template - used only for non-member function pointers. Other types
  22 // either go to one of the below specializations, or go here and fail to compile
  23 // because of base::Bind().
  24 template<typename T, typename Enable = void>
  25 struct CallbackTraits {
  26   static v8::Local<v8::FunctionTemplate> CreateTemplate(v8::Isolate* isolate,
  27                                                          T callback) {
  28     return CreateFunctionTemplate(isolate, base::Bind(callback));
  29   }
  30   static void SetAsFunctionHandler(v8::Isolate* isolate,
  31                                    v8::Local<v8::ObjectTemplate> tmpl,
  32                                    T callback) {
  33     CreateFunctionHandler(isolate, tmpl, base::Bind(callback));
  34   }
  35 };
  36
  37 // Specialization for base::Callback.
  38 template<typename T>
  39 struct CallbackTraits<base::Callback<T> > {
  40   static v8::Local<v8::FunctionTemplate> CreateTemplate(
  41       v8::Isolate* isolate, const base::Callback<T>& callback) {
  42     return CreateFunctionTemplate(isolate, callback);
  43   }
  44   static void SetAsFunctionHandler(v8::Isolate* isolate,
  45                                    v8::Local<v8::ObjectTemplate> tmpl,
  46                                    const base::Callback<T>& callback) {
  47     CreateFunctionHandler(isolate, tmpl, callback);
  48   }
  49 };
  50
  51 // Specialization for member function pointers. We need to handle this case
  52 // specially because the first parameter for callbacks to MFP should typically
  53 // come from the the JavaScript "this" object the function was called on, not
  54 // from the first normal parameter.
  55 template<typename T>
  56 struct CallbackTraits<T, typename base::enable_if<
  57                            base::is_member_function_pointer<T>::value>::type> {
  58   static v8::Local<v8::FunctionTemplate> CreateTemplate(v8::Isolate* isolate,
  59                                                          T callback) {
  60     return CreateFunctionTemplate(isolate, base::Bind(callback),
  61                                   HolderIsFirstArgument);
  62   }
  63   static void SetAsFunctionHandler(v8::Isolate* isolate,
  64                                    v8::Local<v8::ObjectTemplate> tmpl,
  65                                    T callback) {
  66     CreateFunctionHandler(
  67         isolate, tmpl, base::Bind(callback), HolderIsFirstArgument);
  68   }
  69 };
  70
  71 // This specialization allows people to construct function templates directly if
  72 // they need to do fancier stuff.
  73 template<>
  74 struct CallbackTraits<v8::Local<v8::FunctionTemplate> > {
  75   static v8::Local<v8::FunctionTemplate> CreateTemplate(
  76       v8::Local<v8::FunctionTemplate> templ) {
  77     return templ;
  78   }
  79 };
  80
  81 }  // namespace
  82
  83
  84 // ObjectTemplateBuilder provides a handy interface to creating
  85 // v8::ObjectTemplate instances with various sorts of properties.
  86 class GIN_EXPORT ObjectTemplateBuilder {
  87  public:
  88   explicit ObjectTemplateBuilder(v8::Isolate* isolate);
  89   ~ObjectTemplateBuilder();
  90
  91   // It's against Google C++ style to return a non-const ref, but we take some
  92   // poetic license here in order that all calls to Set() can be via the '.'
  93   // operator and line up nicely.
  94   template<typename T>
  95   ObjectTemplateBuilder& SetValue(const base::StringPiece& name, T val) {
  96     return SetImpl(name, ConvertToV8(isolate_, val));
  97   }
  98
  99   // In the following methods, T and U can be function pointer, member function
 100   // pointer, base::Callback, or v8::FunctionTemplate. Most clients will want to
 101   // use one of the first two options. Also see gin::CreateFunctionTemplate()
 102   // for creating raw function templates.
 103   template<typename T>
 104   ObjectTemplateBuilder& SetMethod(const base::StringPiece& name,
 105                                    const T& callback) {
 106     return SetImpl(name, CallbackTraits<T>::CreateTemplate(isolate_, callback));
 107   }
 108   template<typename T>
 109   ObjectTemplateBuilder& SetProperty(const base::StringPiece& name,
 110                                      const T& getter) {
 111     return SetPropertyImpl(name,
 112                            CallbackTraits<T>::CreateTemplate(isolate_, getter),
 113                            v8::Local<v8::FunctionTemplate>());
 114   }
 115   template<typename T, typename U>
 116   ObjectTemplateBuilder& SetProperty(const base::StringPiece& name,
 117                                      const T& getter, const U& setter) {
 118     return SetPropertyImpl(name,
 119                            CallbackTraits<T>::CreateTemplate(isolate_, getter),
 120                            CallbackTraits<U>::CreateTemplate(isolate_, setter));
 121   }
 122   template<typename T>
 123   ObjectTemplateBuilder& SetCallAsFunctionHandler(const T& callback) {
 124     CallbackTraits<T>::SetAsFunctionHandler(isolate_, template_, callback);
 125     return *this;
 126   }
 127   ObjectTemplateBuilder& AddNamedPropertyInterceptor();
 128   ObjectTemplateBuilder& AddIndexedPropertyInterceptor();
 129
 130   v8::Local<v8::ObjectTemplate> Build();
 131
 132  private:
 133   ObjectTemplateBuilder& SetImpl(const base::StringPiece& name,
 134                                  v8::Local<v8::Data> val);
 135   ObjectTemplateBuilder& SetPropertyImpl(
 136       const base::StringPiece& name, v8::Local<v8::FunctionTemplate> getter,
 137       v8::Local<v8::FunctionTemplate> setter);
 138
 139   v8::Isolate* isolate_;
 140
 141   // ObjectTemplateBuilder should only be used on the stack.
 142   v8::Local<v8::ObjectTemplate> template_;
 143 };
 144
 145 }  // namespace gin
 146
 147 #endif  // GIN_OBJECT_TEMPLATE_BUILDER_H_