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 18namespace base { 19namespace 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. 25struct 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*. 31BASE_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. 38BASE_EXPORT JNIEnv* AttachCurrentThreadWithName(const std::string& thread_name); 39 40// Detaches the current thread from VM if it is attached. 41BASE_EXPORT void DetachFromVM(); 42 43// Initializes the global JVM. It is not necessarily called before 44// InitApplicationContext(). 45BASE_EXPORT void InitVM(JavaVM* vm); 46 47// Returns true if the global JVM has been initialized. 48BASE_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. 53BASE_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. 61BASE_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. 68const 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. 75BASE_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|. 84BASE_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. 90class 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*. 117BASE_EXPORT bool HasException(JNIEnv* env); 118 119// If an exception is pending in the provided JNIEnv*, this function clears it 120// and returns true. 121BASE_EXPORT bool ClearException(JNIEnv* env); 122 123// This function will call CHECK() macro if there's any pending exception. 124BASE_EXPORT void CheckException(JNIEnv* env); 125 126} // namespace android 127} // namespace base 128 129#endif // BASE_ANDROID_JNI_ANDROID_H_ 130