gin/arguments.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_ARGUMENTS_H_
   6 #define GIN_ARGUMENTS_H_
   7
   8 #include "base/basictypes.h"
   9 #include "gin/converter.h"
  10 #include "gin/gin_export.h"
  11
  12 namespace gin {
  13
  14 // Arguments is a wrapper around v8::FunctionCallbackInfo that integrates
  15 // with Converter to make it easier to marshall arguments and return values
  16 // between V8 and C++.
  17 class GIN_EXPORT Arguments {
  18  public:
  19   Arguments();
  20   explicit Arguments(const v8::FunctionCallbackInfo<v8::Value>& info);
  21   ~Arguments();
  22
  23   template<typename T>
  24   bool GetHolder(T* out) {
  25     return ConvertFromV8(isolate_, info_->Holder(), out);
  26   }
  27
  28   template<typename T>
  29   bool GetData(T* out) {
  30     return ConvertFromV8(isolate_, info_->Data(), out);
  31   }
  32
  33   template<typename T>
  34   bool GetNext(T* out) {
  35     if (next_ >= info_->Length()) {
  36       insufficient_arguments_ = true;
  37       return false;
  38     }
  39     v8::Local<v8::Value> val = (*info_)[next_++];
  40     return ConvertFromV8(isolate_, val, out);
  41   }
  42
  43   template<typename T>
  44   bool GetRemaining(std::vector<T>* out) {
  45     if (next_ >= info_->Length()) {
  46       insufficient_arguments_ = true;
  47       return false;
  48     }
  49     int remaining = info_->Length() - next_;
  50     out->resize(remaining);
  51     for (int i = 0; i < remaining; ++i) {
  52       v8::Local<v8::Value> val = (*info_)[next_++];
  53       if (!ConvertFromV8(isolate_, val, &out->at(i)))
  54         return false;
  55     }
  56     return true;
  57   }
  58
  59   bool Skip() {
  60     if (next_ >= info_->Length())
  61       return false;
  62     next_++;
  63     return true;
  64   }
  65
  66   int Length() const {
  67     return info_->Length();
  68   }
  69
  70   template<typename T>
  71   void Return(T val) {
  72     v8::Local<v8::Value> v8_value;
  73     if (!TryConvertToV8(isolate_, val, &v8_value))
  74       return;
  75     info_->GetReturnValue().Set(v8_value);
  76   }
  77
  78   // Always check the return value whether the handle is empty before
  79   // dereferencing the handle.
  80   v8::Local<v8::Value> PeekNext() const;
  81
  82   void ThrowError() const;
  83   void ThrowTypeError(const std::string& message) const;
  84
  85   v8::Isolate* isolate() const { return isolate_; }
  86
  87   // Allows the function handler to distinguish between normal invocation
  88   // and object construction.
  89   bool IsConstructCall() const;
  90
  91  private:
  92   v8::Isolate* isolate_;
  93   const v8::FunctionCallbackInfo<v8::Value>* info_;
  94   int next_;
  95   bool insufficient_arguments_;
  96 };
  97
  98 }  // namespace gin
  99
 100 #endif  // GIN_ARGUMENTS_H_