extensions/renderer/v8_helpers.h

   1 // Copyright 2015 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 EXTENSIONS_RENDERER_V8_HELPERS_H_
   6 #define EXTENSIONS_RENDERER_V8_HELPERS_H_
   7
   8 #include <string.h>
   9
  10 #include "v8/include/v8.h"
  11
  12 namespace extensions {
  13 namespace v8_helpers {
  14
  15 // Helper functions for V8 APIs.
  16
  17 // Converts |str| to a V8 string. Returns true on success.
  18 inline bool ToV8String(v8::Isolate* isolate,
  19                        const char* str,
  20                        v8::Local<v8::String>* out) {
  21   return v8::String::NewFromUtf8(isolate, str, v8::NewStringType::kNormal)
  22       .ToLocal(out);
  23 }
  24
  25 inline bool ToV8String(v8::Isolate* isolate,
  26                        const std::string& str,
  27                        v8::Local<v8::String>* out) {
  28   return ToV8String(isolate, str.c_str(), out);
  29 }
  30
  31 // Converts |str| to a V8 string.
  32 // This crashes when strlen(str) > v8::String::kMaxLength.
  33 inline v8::Local<v8::String> ToV8StringUnsafe(
  34     v8::Isolate* isolate,
  35     const char* str,
  36     v8::NewStringType string_type = v8::NewStringType::kNormal) {
  37   DCHECK(strlen(str) <= v8::String::kMaxLength);
  38   return v8::String::NewFromUtf8(isolate, str, string_type)
  39       .ToLocalChecked();
  40 }
  41
  42 inline v8::Local<v8::String> ToV8StringUnsafe(
  43     v8::Isolate* isolate,
  44     const std::string& str,
  45     v8::NewStringType string_type = v8::NewStringType::kNormal) {
  46   return ToV8StringUnsafe(isolate, str.c_str(), string_type);
  47 }
  48
  49 // Returns true if |maybe| is both a value, and that value is true.
  50 inline bool IsTrue(v8::Maybe<bool> maybe) {
  51   return maybe.IsJust() && maybe.FromJust();
  52 }
  53
  54 // Returns true if |value| is empty or undefined.
  55 inline bool IsEmptyOrUndefied(v8::Local<v8::Value> value) {
  56   return value.IsEmpty() || value->IsUndefined();
  57 }
  58
  59 // SetProperty() family wraps V8::Object::Set(). Returns true on success.
  60 inline bool SetProperty(v8::Local<v8::Context> context,
  61                         v8::Local<v8::Object> object,
  62                         v8::Local<v8::Value> key,
  63                         v8::Local<v8::Value> value) {
  64   return IsTrue(object->Set(context, key, value));
  65 }
  66
  67 inline bool SetProperty(v8::Local<v8::Context> context,
  68                         v8::Local<v8::Object> object,
  69                         uint32_t index,
  70                         v8::Local<v8::Value> value) {
  71   return IsTrue(object->Set(context, index, value));
  72 }
  73
  74 inline bool SetProperty(v8::Local<v8::Context> context,
  75                         v8::Local<v8::Object> object,
  76                         const char* key,
  77                         v8::Local<v8::Value> value) {
  78   v8::Local<v8::String> v8_key;
  79   if (!ToV8String(context->GetIsolate(), key, &v8_key))
  80     return false;
  81   return SetProperty(context, object, v8_key, value);
  82 }
  83
  84 // GetProperty() family calls V8::Object::Get() and extracts a value from
  85 // returned MaybeLocal. Returns true on success.
  86 template <typename Key>
  87 inline bool GetProperty(v8::Local<v8::Context> context,
  88                         v8::Local<v8::Object> object,
  89                         Key key,
  90                         v8::Local<v8::Value>* out) {
  91   return object->Get(context, key).ToLocal(out);
  92 }
  93
  94 inline bool GetProperty(v8::Local<v8::Context> context,
  95                         v8::Local<v8::Object> object,
  96                         const char* key,
  97                         v8::Local<v8::Value>* out) {
  98   v8::Local<v8::String> v8_key;
  99   if (!ToV8String(context->GetIsolate(), key, &v8_key))
 100     return false;
 101   return GetProperty(context, object, v8_key, out);
 102 }
 103
 104 // GetPropertyUnsafe() family wraps v8::Object::Get(). They crash when an
 105 // exception is thrown.
 106 inline v8::Local<v8::Value> GetPropertyUnsafe(v8::Local<v8::Context> context,
 107                                               v8::Local<v8::Object> object,
 108                                               v8::Local<v8::Value> key) {
 109   return object->Get(context, key).ToLocalChecked();
 110 }
 111
 112 inline v8::Local<v8::Value> GetPropertyUnsafe(
 113     v8::Local<v8::Context> context,
 114     v8::Local<v8::Object> object,
 115     const char* key,
 116     v8::NewStringType string_type = v8::NewStringType::kNormal) {
 117   return object->Get(context,
 118                      ToV8StringUnsafe(context->GetIsolate(), key, string_type))
 119       .ToLocalChecked();
 120 }
 121
 122 // Wraps v8::Function::Call(). Returns true on success.
 123 inline bool CallFunction(v8::Local<v8::Context> context,
 124                          v8::Local<v8::Function> function,
 125                          v8::Local<v8::Value> recv,
 126                          int argc,
 127                          v8::Local<v8::Value> argv[],
 128                          v8::Local<v8::Value>* out) {
 129   return function->Call(context, recv, argc, argv).ToLocal(out);
 130 }
 131
 132 }  // namespace v8_helpers
 133 }  // namespace extensions
 134
 135 #endif  // EXTENSIONS_RENDERER_V8_HELPERS_H_