extensions: Use V8 Maybe APIs in ModuleSystem

extensions/renderer/v8_helpers.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef EXTENSIONS_RENDERER_V8_HELPERS_H_
+#define EXTENSIONS_RENDERER_V8_HELPERS_H_
+
+#include <string.h>
+
+#include "v8/include/v8.h"
+
+namespace extensions {
+namespace v8_helpers {
+
+// Helper functions for V8 APIs.
+
+// Converts |str| to a V8 string. Returns true on success.
+inline bool ToV8String(v8::Isolate* isolate,
+                       const char* str,
+                       v8::Local<v8::String>* out) {
+  return v8::String::NewFromUtf8(isolate, str, v8::NewStringType::kNormal)
+      .ToLocal(out);
+}
+
+// Converts |str| to a V8 string.
+// This crashes when strlen(str) > v8::String::kMaxLength.
+inline v8::Local<v8::String> ToV8StringUnsafe(
+    v8::Isolate* isolate,
+    const char* str,
+    v8::NewStringType string_type = v8::NewStringType::kNormal) {
+  DCHECK(strlen(str) <= v8::String::kMaxLength);
+  return v8::String::NewFromUtf8(isolate, str, string_type)
+      .ToLocalChecked();
+}
+
+// Returns true if |maybe| is both a value, and that value is true.
+inline bool IsTrue(v8::Maybe<bool> maybe) {
+  return maybe.IsJust() && maybe.FromJust();
+}
+
+// SetProperty() family wraps V8::Object::Set(). Returns true on success.
+inline bool SetProperty(v8::Local<v8::Context> context,
+                        v8::Local<v8::Object> object,
+                        v8::Local<v8::Value> key,
+                        v8::Local<v8::Value> value) {
+  return IsTrue(object->Set(context, key, value));
+}
+
+inline bool SetProperty(v8::Local<v8::Context> context,
+                        v8::Local<v8::Object> object,
+                        uint32_t index,
+                        v8::Local<v8::Value> value) {
+  return IsTrue(object->Set(context, index, value));
+}
+
+inline bool SetProperty(v8::Local<v8::Context> context,
+                        v8::Local<v8::Object> object,
+                        const char* key,
+                        v8::Local<v8::Value> value) {
+  v8::Local<v8::String> v8_key;
+  if (!ToV8String(context->GetIsolate(), key, &v8_key))
+    return false;
+  return SetProperty(context, object, v8_key, value);
+}
+
+// GetProperty() family calls V8::Object::Get() and extracts a value from
+// returned MaybeLocal. Returns true on success.
+inline bool GetProperty(v8::Local<v8::Context> context,
+                        v8::Local<v8::Object> object,
+                        v8::Local<v8::Value> key,
+                        v8::Local<v8::Value>* out) {
+  return object->Get(context, key).ToLocal(out);
+}
+
+inline bool GetProperty(v8::Local<v8::Context> context,
+                        v8::Local<v8::Object> object,
+                        const char* key,
+                        v8::Local<v8::Value>* out) {
+  v8::Local<v8::String> v8_key;
+  if (!ToV8String(context->GetIsolate(), key, &v8_key))
+    return false;
+  return GetProperty(context, object, v8_key, out);
+}
+
+// GetPropertyUnsafe() family wraps v8::Object::Get(). They crash when an
+// exception is thrown.
+inline v8::Local<v8::Value> GetPropertyUnsafe(v8::Local<v8::Context> context,
+                                              v8::Local<v8::Object> object,
+                                              v8::Local<v8::Value> key) {
+  return object->Get(context, key).ToLocalChecked();
+}
+
+inline v8::Local<v8::Value> GetPropertyUnsafe(
+    v8::Local<v8::Context> context,
+    v8::Local<v8::Object> object,
+    const char* key,
+    v8::NewStringType string_type = v8::NewStringType::kNormal) {
+  return object->Get(context,
+                     ToV8StringUnsafe(context->GetIsolate(), key, string_type))
+      .ToLocalChecked();
+}
+
+}  // namespace v8_helpers
+}  // namespace extensions
+
+#endif  // EXTENSIONS_RENDERER_V8_HELPERS_H_