| // Copyright 2014 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. |
| |
| #include "content/browser/android/java/jni_helper.h" |
| |
| #include <map> |
| |
| #include "base/android/jni_android.h" |
| #include "base/lazy_instance.h" |
| #include "base/threading/platform_thread.h" |
| |
| namespace content { |
| |
| namespace { |
| |
| struct MethodIdentifier { |
| const char* class_name; |
| const char* method; |
| const char* jni_signature; |
| |
| bool operator<(const MethodIdentifier& other) const { |
| int r = strcmp(class_name, other.class_name); |
| if (r < 0) { |
| return true; |
| } else if (r > 0) { |
| return false; |
| } |
| |
| r = strcmp(method, other.method); |
| if (r < 0) { |
| return true; |
| } else if (r > 0) { |
| return false; |
| } |
| |
| return strcmp(jni_signature, other.jni_signature) < 0; |
| } |
| }; |
| |
| typedef std::map<MethodIdentifier, jmethodID> MethodIDMap; |
| |
| const base::subtle::AtomicWord kUnlocked = 0; |
| const base::subtle::AtomicWord kLocked = 1; |
| base::subtle::AtomicWord g_method_id_map_lock = kUnlocked; |
| |
| base::LazyInstance<MethodIDMap> g_method_id_map = LAZY_INSTANCE_INITIALIZER; |
| |
| } // namespace |
| |
| jmethodID GetMethodIDFromClassName(JNIEnv* env, |
| const char* class_name, |
| const char* method, |
| const char* jni_signature) { |
| MethodIdentifier key; |
| key.class_name = class_name; |
| key.method = method; |
| key.jni_signature = jni_signature; |
| |
| MethodIDMap* map = g_method_id_map.Pointer(); |
| bool found = false; |
| |
| while (base::subtle::Acquire_CompareAndSwap(&g_method_id_map_lock, |
| kUnlocked, |
| kLocked) != kUnlocked) { |
| base::PlatformThread::YieldCurrentThread(); |
| } |
| MethodIDMap::const_iterator iter = map->find(key); |
| if (iter != map->end()) { |
| found = true; |
| } |
| base::subtle::Release_Store(&g_method_id_map_lock, kUnlocked); |
| |
| // Addition to the map does not invalidate this iterator. |
| if (found) { |
| return iter->second; |
| } |
| |
| base::android::ScopedJavaLocalRef<jclass> clazz( |
| env, env->FindClass(class_name)); |
| jmethodID id = base::android::MethodID::Get< |
| base::android::MethodID::TYPE_INSTANCE>( |
| env, clazz.obj(), method, jni_signature); |
| |
| while (base::subtle::Acquire_CompareAndSwap(&g_method_id_map_lock, |
| kUnlocked, |
| kLocked) != kUnlocked) { |
| base::PlatformThread::YieldCurrentThread(); |
| } |
| // Another thread may have populated the map already. |
| std::pair<MethodIDMap::const_iterator, bool> result = |
| map->insert(std::make_pair(key, id)); |
| DCHECK_EQ(id, result.first->second); |
| base::subtle::Release_Store(&g_method_id_map_lock, kUnlocked); |
| |
| return id; |
| } |
| |
| } // namespace content |