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 #ifndef BASE_ANDROID_JNI_ANDROID_H_ 6 #define BASE_ANDROID_JNI_ANDROID_H_ 7 8 #include <jni.h> 9 #include <sys/types.h> 10 11 #include <string> 12 13 #include "base/android/scoped_java_ref.h" 14 #include "base/atomicops.h" 15 #include "base/base_export.h" 16 #include "base/compiler_specific.h" 17 18 namespace base { 19 namespace android { 20 21 // Used to mark symbols to be exported in a shared library's symbol table. 22 #define JNI_EXPORT __attribute__ ((visibility("default"))) 23 24 // Contains the registration method information for initializing JNI bindings. 25 struct RegistrationMethod { 26 const char* name; 27 bool (*func)(JNIEnv* env); 28 }; 29 30 // Attaches the current thread to the VM (if necessary) and return the JNIEnv*. 31 BASE_EXPORT JNIEnv* AttachCurrentThread(); 32 33 // Same to AttachCurrentThread except that thread name will be set to 34 // |thread_name| if it is the first call. Otherwise, thread_name won't be 35 // changed. AttachCurrentThread() doesn't regard underlying platform thread 36 // name, but just resets it to "Thread-???". This function should be called 37 // right after new thread is created if it is important to keep thread name. 38 BASE_EXPORT JNIEnv* AttachCurrentThreadWithName(const std::string& thread_name); 39 40 // Detaches the current thread from VM if it is attached. 41 BASE_EXPORT void DetachFromVM(); 42 43 // Initializes the global JVM. It is not necessarily called before 44 // InitApplicationContext(). 45 BASE_EXPORT void InitVM(JavaVM* vm); 46 47 // Returns true if the global JVM has been initialized. 48 BASE_EXPORT bool IsVMInitialized(); 49 50 // Initializes the global application context object. The |context| can be any 51 // valid reference to the application context. Internally holds a global ref to 52 // the context. InitVM and InitApplicationContext maybe called in either order. 53 BASE_EXPORT void InitApplicationContext(JNIEnv* env, 54 const JavaRef<jobject>& context); 55 56 // Initializes the global ClassLoader used by the GetClass and LazyGetClass 57 // methods. This is needed because JNI will use the base ClassLoader when there 58 // is no Java code on the stack. The base ClassLoader doesn't know about any of 59 // the application classes and will fail to lookup anything other than system 60 // classes. 61 BASE_EXPORT void InitReplacementClassLoader( 62 JNIEnv* env, 63 const JavaRef<jobject>& class_loader); 64 65 // Gets a global ref to the application context set with 66 // InitApplicationContext(). Ownership is retained by the function - the caller 67 // must NOT release it. 68 const BASE_EXPORT jobject GetApplicationContext(); 69 70 // Finds the class named |class_name| and returns it. 71 // Use this method instead of invoking directly the JNI FindClass method (to 72 // prevent leaking local references). 73 // This method triggers a fatal assertion if the class could not be found. 74 // Use HasClass if you need to check whether the class exists. 75 BASE_EXPORT ScopedJavaLocalRef<jclass> GetClass(JNIEnv* env, 76 const char* class_name); 77 78 // The method will initialize |atomic_class_id| to contain a global ref to the 79 // class. And will return that ref on subsequent calls. It's the caller's 80 // responsibility to release the ref when it is no longer needed. 81 // The caller is responsible to zero-initialize |atomic_method_id|. 82 // It's fine to simultaneously call this on multiple threads referencing the 83 // same |atomic_method_id|. 84 BASE_EXPORT jclass LazyGetClass( 85 JNIEnv* env, 86 const char* class_name, 87 base::subtle::AtomicWord* atomic_class_id); 88 89 // This class is a wrapper for JNIEnv Get(Static)MethodID. 90 class BASE_EXPORT MethodID { 91 public: 92 enum Type { 93 TYPE_STATIC, 94 TYPE_INSTANCE, 95 }; 96 97 // Returns the method ID for the method with the specified name and signature. 98 // This method triggers a fatal assertion if the method could not be found. 99 template<Type type> 100 static jmethodID Get(JNIEnv* env, 101 jclass clazz, 102 const char* method_name, 103 const char* jni_signature); 104 105 // The caller is responsible to zero-initialize |atomic_method_id|. 106 // It's fine to simultaneously call this on multiple threads referencing the 107 // same |atomic_method_id|. 108 template<Type type> 109 static jmethodID LazyGet(JNIEnv* env, 110 jclass clazz, 111 const char* method_name, 112 const char* jni_signature, 113 base::subtle::AtomicWord* atomic_method_id); 114 }; 115 116 // Returns true if an exception is pending in the provided JNIEnv*. 117 BASE_EXPORT bool HasException(JNIEnv* env); 118 119 // If an exception is pending in the provided JNIEnv*, this function clears it 120 // and returns true. 121 BASE_EXPORT bool ClearException(JNIEnv* env); 122 123 // This function will call CHECK() macro if there's any pending exception. 124 BASE_EXPORT void CheckException(JNIEnv* env); 125 126 } // namespace android 127 } // namespace base 128 129 #endif // BASE_ANDROID_JNI_ANDROID_H_ 130
