extensions/renderer/binding_generating_native_handler.cc

   1 // Copyright 2014 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 #include "extensions/renderer/binding_generating_native_handler.h"
   6
   7 #include "extensions/renderer/script_context.h"
   8 #include "extensions/renderer/v8_helpers.h"
   9
  10 namespace extensions {
  11
  12 using namespace v8_helpers;
  13
  14 BindingGeneratingNativeHandler::BindingGeneratingNativeHandler(
  15     ScriptContext* context,
  16     const std::string& api_name,
  17     const std::string& bind_to)
  18     : context_(context), api_name_(api_name), bind_to_(bind_to) {}
  19
  20 v8::Local<v8::Object> BindingGeneratingNativeHandler::NewInstance() {
  21   // This long sequence of commands effectively runs the JavaScript code,
  22   // such that result[bind_to] is the compiled schema for |api_name|:
  23   //
  24   //   var result = {};
  25   //   result[bind_to] = require('binding').Binding.create(api_name).generate();
  26   //   return result;
  27   //
  28   // Unfortunately using the v8 APIs makes that quite verbose.
  29   // Each stage is marked with the code it executes.
  30   v8::Isolate* isolate = context_->isolate();
  31   v8::EscapableHandleScope scope(isolate);
  32
  33   // Convert |api_name| and |bind_to| into their v8::Strings to pass
  34   // through the v8 APIs.
  35   v8::Local<v8::String> v8_api_name;
  36   v8::Local<v8::String> v8_bind_to;
  37   if (!ToV8String(isolate, api_name_, &v8_api_name) ||
  38       !ToV8String(isolate, bind_to_, &v8_bind_to)) {
  39     NOTREACHED();
  40     return v8::Local<v8::Object>();
  41   }
  42
  43   v8::Local<v8::Context> v8_context = context_->v8_context();
  44
  45   // require('binding');
  46   v8::Local<v8::Object> binding_module;
  47   if (!context_->module_system()->Require("binding").ToLocal(&binding_module)) {
  48     NOTREACHED();
  49     return v8::Local<v8::Object>();
  50   }
  51
  52   // require('binding').Binding;
  53   v8::Local<v8::Value> binding_value;
  54   v8::Local<v8::Object> binding;
  55   if (!GetProperty(v8_context, binding_module, "Binding", &binding_value) ||
  56       !binding_value->ToObject(v8_context).ToLocal(&binding)) {
  57     NOTREACHED();
  58     return v8::Local<v8::Object>();
  59   }
  60
  61   // require('binding').Binding.create;
  62   v8::Local<v8::Value> create_binding_value;
  63   if (!GetProperty(v8_context, binding, "create", &create_binding_value) ||
  64       !create_binding_value->IsFunction()) {
  65     NOTREACHED();
  66     return v8::Local<v8::Object>();
  67   }
  68   v8::Local<v8::Function> create_binding =
  69       create_binding_value.As<v8::Function>();
  70
  71   // require('Binding').Binding.create(api_name);
  72   v8::Local<v8::Value> argv[] = {v8_api_name};
  73   v8::Local<v8::Value> binding_instance_value;
  74   v8::Local<v8::Object> binding_instance;
  75   if (!CallFunction(v8_context, create_binding, binding, arraysize(argv), argv,
  76                     &binding_instance_value) ||
  77       !binding_instance_value->ToObject(v8_context)
  78            .ToLocal(&binding_instance)) {
  79     NOTREACHED();
  80     return v8::Local<v8::Object>();
  81   }
  82
  83   // require('binding').Binding.create(api_name).generate;
  84   v8::Local<v8::Value> generate_value;
  85   if (!GetProperty(v8_context, binding_instance, "generate", &generate_value) ||
  86       !generate_value->IsFunction()) {
  87     NOTREACHED();
  88     return v8::Local<v8::Object>();
  89   }
  90   v8::Local<v8::Function> generate = generate_value.As<v8::Function>();
  91
  92   // require('binding').Binding.create(api_name).generate();
  93   v8::Local<v8::Object> object = v8::Object::New(isolate);
  94   v8::Local<v8::Value> compiled_schema;
  95   if (!CallFunction(v8_context, generate, binding_instance, 0, nullptr,
  96                     &compiled_schema)) {
  97     NOTREACHED();
  98     return v8::Local<v8::Object>();
  99   }
 100
 101   // var result = {};
 102   // result[bind_to] = ...;
 103   if (!SetProperty(v8_context, object, v8_bind_to, compiled_schema)) {
 104     NOTREACHED();
 105     return v8::Local<v8::Object>();
 106   }
 107   // return result;
 108   return scope.Escape(object);
 109 }
 110
 111 }  // namespace extensions