OLD | NEW |
| (Empty) |
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 #include "content/browser/renderer_host/java/jni_helper.h" | |
6 | |
7 #include <map> | |
8 | |
9 #include "base/android/jni_android.h" | |
10 #include "base/lazy_instance.h" | |
11 #include "base/threading/platform_thread.h" | |
12 | |
13 namespace content { | |
14 | |
15 namespace { | |
16 | |
17 struct MethodIdentifier { | |
18 const char* class_name; | |
19 const char* method; | |
20 const char* jni_signature; | |
21 | |
22 bool operator<(const MethodIdentifier& other) const { | |
23 int r = strcmp(class_name, other.class_name); | |
24 if (r < 0) { | |
25 return true; | |
26 } else if (r > 0) { | |
27 return false; | |
28 } | |
29 | |
30 r = strcmp(method, other.method); | |
31 if (r < 0) { | |
32 return true; | |
33 } else if (r > 0) { | |
34 return false; | |
35 } | |
36 | |
37 return strcmp(jni_signature, other.jni_signature) < 0; | |
38 } | |
39 }; | |
40 | |
41 typedef std::map<MethodIdentifier, jmethodID> MethodIDMap; | |
42 | |
43 const base::subtle::AtomicWord kUnlocked = 0; | |
44 const base::subtle::AtomicWord kLocked = 1; | |
45 base::subtle::AtomicWord g_method_id_map_lock = kUnlocked; | |
46 | |
47 base::LazyInstance<MethodIDMap> g_method_id_map = LAZY_INSTANCE_INITIALIZER; | |
48 | |
49 } // namespace | |
50 | |
51 jmethodID GetMethodIDFromClassName(JNIEnv* env, | |
52 const char* class_name, | |
53 const char* method, | |
54 const char* jni_signature) { | |
55 MethodIdentifier key; | |
56 key.class_name = class_name; | |
57 key.method = method; | |
58 key.jni_signature = jni_signature; | |
59 | |
60 MethodIDMap* map = g_method_id_map.Pointer(); | |
61 bool found = false; | |
62 | |
63 while (base::subtle::Acquire_CompareAndSwap(&g_method_id_map_lock, | |
64 kUnlocked, | |
65 kLocked) != kUnlocked) { | |
66 base::PlatformThread::YieldCurrentThread(); | |
67 } | |
68 MethodIDMap::const_iterator iter = map->find(key); | |
69 if (iter != map->end()) { | |
70 found = true; | |
71 } | |
72 base::subtle::Release_Store(&g_method_id_map_lock, kUnlocked); | |
73 | |
74 // Addition to the map does not invalidate this iterator. | |
75 if (found) { | |
76 return iter->second; | |
77 } | |
78 | |
79 base::android::ScopedJavaLocalRef<jclass> clazz( | |
80 env, env->FindClass(class_name)); | |
81 jmethodID id = base::android::MethodID::Get< | |
82 base::android::MethodID::TYPE_INSTANCE>( | |
83 env, clazz.obj(), method, jni_signature); | |
84 | |
85 while (base::subtle::Acquire_CompareAndSwap(&g_method_id_map_lock, | |
86 kUnlocked, | |
87 kLocked) != kUnlocked) { | |
88 base::PlatformThread::YieldCurrentThread(); | |
89 } | |
90 // Another thread may have populated the map already. | |
91 std::pair<MethodIDMap::const_iterator, bool> result = | |
92 map->insert(std::make_pair(key, id)); | |
93 DCHECK_EQ(id, result.first->second); | |
94 base::subtle::Release_Store(&g_method_id_map_lock, kUnlocked); | |
95 | |
96 return id; | |
97 } | |
98 | |
99 } // namespace content | |
OLD | NEW |