jni_android.cc revision c2e0dbddbe15c98d52c4786dac06cb8952a8ae6d 
1// Copyright (c) 2012 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 "base/android/jni_android.h"
6
7#include <map>
8
9#include "base/android/build_info.h"
10#include "base/android/jni_string.h"
11#include "base/lazy_instance.h"
12#include "base/logging.h"
13#include "base/threading/platform_thread.h"
14
15namespace {
16using base::android::GetClass;
17using base::android::MethodID;
18using base::android::ScopedJavaLocalRef;
19
20struct MethodIdentifier {
21  const char* class_name;
22  const char* method;
23  const char* jni_signature;
24
25  bool operator<(const MethodIdentifier& other) const {
26    int r = strcmp(class_name, other.class_name);
27    if (r < 0) {
28      return true;
29    } else if (r > 0) {
30      return false;
31    }
32
33    r = strcmp(method, other.method);
34    if (r < 0) {
35      return true;
36    } else if (r > 0) {
37      return false;
38    }
39
40    return strcmp(jni_signature, other.jni_signature) < 0;
41  }
42};
43
44typedef std::map<MethodIdentifier, jmethodID> MethodIDMap;
45
46const base::subtle::AtomicWord kUnlocked = 0;
47const base::subtle::AtomicWord kLocked = 1;
48base::subtle::AtomicWord g_method_id_map_lock = kUnlocked;
49JavaVM* g_jvm = NULL;
50// Leak the global app context, as it is used from a non-joinable worker thread
51// that may still be running at shutdown. There is no harm in doing this.
52base::LazyInstance<base::android::ScopedJavaGlobalRef<jobject> >::Leaky
53    g_application_context = LAZY_INSTANCE_INITIALIZER;
54base::LazyInstance<MethodIDMap> g_method_id_map = LAZY_INSTANCE_INITIALIZER;
55
56std::string GetJavaExceptionInfo(JNIEnv* env, jthrowable java_throwable) {
57  ScopedJavaLocalRef<jclass> throwable_clazz =
58      GetClass(env, "java/lang/Throwable");
59  jmethodID throwable_printstacktrace =
60      MethodID::Get<MethodID::TYPE_INSTANCE>(
61          env, throwable_clazz.obj(), "printStackTrace",
62          "(Ljava/io/PrintStream;)V");
63
64  // Create an instance of ByteArrayOutputStream.
65  ScopedJavaLocalRef<jclass> bytearray_output_stream_clazz =
66      GetClass(env, "java/io/ByteArrayOutputStream");
67  jmethodID bytearray_output_stream_constructor =
68      MethodID::Get<MethodID::TYPE_INSTANCE>(
69          env, bytearray_output_stream_clazz.obj(), "<init>", "()V");
70  jmethodID bytearray_output_stream_tostring =
71      MethodID::Get<MethodID::TYPE_INSTANCE>(
72          env, bytearray_output_stream_clazz.obj(), "toString",
73          "()Ljava/lang/String;");
74  ScopedJavaLocalRef<jobject> bytearray_output_stream(env,
75      env->NewObject(bytearray_output_stream_clazz.obj(),
76                     bytearray_output_stream_constructor));
77
78  // Create an instance of PrintStream.
79  ScopedJavaLocalRef<jclass> printstream_clazz =
80      GetClass(env, "java/io/PrintStream");
81  jmethodID printstream_constructor =
82      MethodID::Get<MethodID::TYPE_INSTANCE>(
83          env, printstream_clazz.obj(), "<init>",
84          "(Ljava/io/OutputStream;)V");
85  ScopedJavaLocalRef<jobject> printstream(env,
86      env->NewObject(printstream_clazz.obj(), printstream_constructor,
87                     bytearray_output_stream.obj()));
88
89  // Call Throwable.printStackTrace(PrintStream)
90  env->CallVoidMethod(java_throwable, throwable_printstacktrace,
91      printstream.obj());
92
93  // Call ByteArrayOutputStream.toString()
94  ScopedJavaLocalRef<jstring> exception_string(
95      env, static_cast<jstring>(
96          env->CallObjectMethod(bytearray_output_stream.obj(),
97                                bytearray_output_stream_tostring)));
98
99  return ConvertJavaStringToUTF8(exception_string);
100}
101
102}  // namespace
103
104namespace base {
105namespace android {
106
107JNIEnv* AttachCurrentThread() {
108  DCHECK(g_jvm);
109  JNIEnv* env = NULL;
110  jint ret = g_jvm->AttachCurrentThread(&env, NULL);
111  DCHECK_EQ(JNI_OK, ret);
112  return env;
113}
114
115void DetachFromVM() {
116  // Ignore the return value, if the thread is not attached, DetachCurrentThread
117  // will fail. But it is ok as the native thread may never be attached.
118  if (g_jvm)
119    g_jvm->DetachCurrentThread();
120}
121
122void InitVM(JavaVM* vm) {
123  DCHECK(!g_jvm);
124  g_jvm = vm;
125}
126
127void InitApplicationContext(const JavaRef<jobject>& context) {
128  DCHECK(g_application_context.Get().is_null());
129  g_application_context.Get().Reset(context);
130}
131
132const jobject GetApplicationContext() {
133  DCHECK(!g_application_context.Get().is_null());
134  return g_application_context.Get().obj();
135}
136
137ScopedJavaLocalRef<jclass> GetClass(JNIEnv* env, const char* class_name) {
138  jclass clazz = env->FindClass(class_name);
139  CHECK(!ClearException(env) && clazz) << "Failed to find class " << class_name;
140  return ScopedJavaLocalRef<jclass>(env, clazz);
141}
142
143bool HasClass(JNIEnv* env, const char* class_name) {
144  ScopedJavaLocalRef<jclass> clazz(env, env->FindClass(class_name));
145  if (!clazz.obj()) {
146    ClearException(env);
147    return false;
148  }
149  bool error = ClearException(env);
150  DCHECK(!error);
151  return true;
152}
153
154template<MethodID::Type type>
155jmethodID MethodID::Get(JNIEnv* env,
156                        jclass clazz,
157                        const char* method_name,
158                        const char* jni_signature) {
159  jmethodID id = type == TYPE_STATIC ?
160      env->GetStaticMethodID(clazz, method_name, jni_signature) :
161      env->GetMethodID(clazz, method_name, jni_signature);
162  CHECK(base::android::ClearException(env) || id) <<
163      "Failed to find " <<
164      (type == TYPE_STATIC ? "static " : "") <<
165      "method " << method_name << " " << jni_signature;
166  return id;
167}
168
169// If |atomic_method_id| set, it'll return immediately. Otherwise, it'll call
170// into ::Get() above. If there's a race, it's ok since the values are the same
171// (and the duplicated effort will happen only once).
172template<MethodID::Type type>
173jmethodID MethodID::LazyGet(JNIEnv* env,
174                            jclass clazz,
175                            const char* method_name,
176                            const char* jni_signature,
177                            base::subtle::AtomicWord* atomic_method_id) {
178  COMPILE_ASSERT(sizeof(subtle::AtomicWord) >= sizeof(jmethodID),
179                 AtomicWord_SmallerThan_jMethodID);
180  subtle::AtomicWord value = base::subtle::Acquire_Load(atomic_method_id);
181  if (value)
182    return reinterpret_cast<jmethodID>(value);
183  jmethodID id = MethodID::Get<type>(env, clazz, method_name, jni_signature);
184  base::subtle::Release_Store(
185      atomic_method_id, reinterpret_cast<subtle::AtomicWord>(id));
186  return id;
187}
188
189// Various template instantiations.
190template jmethodID MethodID::Get<MethodID::TYPE_STATIC>(
191    JNIEnv* env, jclass clazz, const char* method_name,
192    const char* jni_signature);
193
194template jmethodID MethodID::Get<MethodID::TYPE_INSTANCE>(
195    JNIEnv* env, jclass clazz, const char* method_name,
196    const char* jni_signature);
197
198template jmethodID MethodID::LazyGet<MethodID::TYPE_STATIC>(
199    JNIEnv* env, jclass clazz, const char* method_name,
200    const char* jni_signature, base::subtle::AtomicWord* atomic_method_id);
201
202template jmethodID MethodID::LazyGet<MethodID::TYPE_INSTANCE>(
203    JNIEnv* env, jclass clazz, const char* method_name,
204    const char* jni_signature, base::subtle::AtomicWord* atomic_method_id);
205
206jfieldID GetFieldID(JNIEnv* env,
207                    const JavaRef<jclass>& clazz,
208                    const char* field_name,
209                    const char* jni_signature) {
210  jfieldID field_id = env->GetFieldID(clazz.obj(), field_name, jni_signature);
211  CHECK(!ClearException(env) && field_id) << "Failed to find field " <<
212      field_name << " " << jni_signature;
213  return field_id;
214}
215
216bool HasField(JNIEnv* env,
217              const JavaRef<jclass>& clazz,
218              const char* field_name,
219              const char* jni_signature) {
220  jfieldID field_id = env->GetFieldID(clazz.obj(), field_name, jni_signature);
221  if (!field_id) {
222    ClearException(env);
223    return false;
224  }
225  bool error = ClearException(env);
226  DCHECK(!error);
227  return true;
228}
229
230jfieldID GetStaticFieldID(JNIEnv* env,
231                          const JavaRef<jclass>& clazz,
232                          const char* field_name,
233                          const char* jni_signature) {
234  jfieldID field_id =
235      env->GetStaticFieldID(clazz.obj(), field_name, jni_signature);
236  CHECK(!ClearException(env) && field_id) << "Failed to find static field " <<
237      field_name << " " << jni_signature;
238  return field_id;
239}
240
241jmethodID GetMethodIDFromClassName(JNIEnv* env,
242                                   const char* class_name,
243                                   const char* method,
244                                   const char* jni_signature) {
245  MethodIdentifier key;
246  key.class_name = class_name;
247  key.method = method;
248  key.jni_signature = jni_signature;
249
250  MethodIDMap* map = g_method_id_map.Pointer();
251  bool found = false;
252
253  while (base::subtle::Acquire_CompareAndSwap(&g_method_id_map_lock,
254                                              kUnlocked,
255                                              kLocked) != kUnlocked) {
256    base::PlatformThread::YieldCurrentThread();
257  }
258  MethodIDMap::const_iterator iter = map->find(key);
259  if (iter != map->end()) {
260    found = true;
261  }
262  base::subtle::Release_Store(&g_method_id_map_lock, kUnlocked);
263
264  // Addition to the map does not invalidate this iterator.
265  if (found) {
266    return iter->second;
267  }
268
269  ScopedJavaLocalRef<jclass> clazz(env, env->FindClass(class_name));
270  jmethodID id = MethodID::Get<MethodID::TYPE_INSTANCE>(
271      env, clazz.obj(), method, jni_signature);
272
273  while (base::subtle::Acquire_CompareAndSwap(&g_method_id_map_lock,
274                                              kUnlocked,
275                                              kLocked) != kUnlocked) {
276    base::PlatformThread::YieldCurrentThread();
277  }
278  // Another thread may have populated the map already.
279  std::pair<MethodIDMap::const_iterator, bool> result =
280      map->insert(std::make_pair(key, id));
281  DCHECK_EQ(id, result.first->second);
282  base::subtle::Release_Store(&g_method_id_map_lock, kUnlocked);
283
284  return id;
285}
286
287bool HasException(JNIEnv* env) {
288  return env->ExceptionCheck() != JNI_FALSE;
289}
290
291bool ClearException(JNIEnv* env) {
292  if (!HasException(env))
293    return false;
294  env->ExceptionDescribe();
295  env->ExceptionClear();
296  return true;
297}
298
299void CheckException(JNIEnv* env) {
300  if (!HasException(env)) return;
301
302  // Exception has been found, might as well tell breakpad about it.
303  jthrowable java_throwable = env->ExceptionOccurred();
304  if (!java_throwable) {
305    // Do nothing but return false.
306    CHECK(false);
307  }
308
309  // Clear the pending exception, since a local reference is now held.
310  env->ExceptionDescribe();
311  env->ExceptionClear();
312
313  // Set the exception_string in BuildInfo so that breakpad can read it.
314  // RVO should avoid any extra copies of the exception string.
315  base::android::BuildInfo::GetInstance()->set_java_exception_info(
316      GetJavaExceptionInfo(env, java_throwable));
317
318  // Now, feel good about it and die.
319  CHECK(false);
320}
321
322}  // namespace android
323}  // namespace base
324