blob: abaccd1ad2705e47d11c708cb80f6f12927cf186 [file] [log] [blame]
// Copyright (c) 2012 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 <jni.h>
#include <sys/types.h>
#include <string>
#include "base/android/scoped_java_ref.h"
#include "base/atomicops.h"
#include "base/base_export.h"
#include "base/compiler_specific.h"
#include "base/debug/debugging_flags.h"
#include "base/debug/stack_trace.h"
#include "base/macros.h"
// When profiling is enabled (enable_profiling=true) this macro is added to
// all generated JNI stubs so that it becomes the last thing that runs before
// control goes into Java.
// This macro saves stack frame pointer of the current function. Saved value
base::android::JNIStackFrameSaver jni_frame_saver(__builtin_frame_address(0))
// When profiling is enabled (enable_profiling=true) this macro is added to
// all generated JNI callbacks so that it becomes the first thing that runs
// after control returns from Java.
// This macro links stack frame of the current function to the stack frame
// saved by JNI_SAVE_FRAME_POINTER, allowing frame-based unwinding
// (used by the heap profiler) to produce complete traces.
base::debug::ScopedStackFrameLinker jni_frame_linker( \
__builtin_frame_address(0), \
// Frame-based stack unwinding is not supported, do nothing.
namespace base {
namespace android {
// Used to mark symbols to be exported in a shared library's symbol table.
#define JNI_EXPORT __attribute__ ((visibility("default")))
// Contains the registration method information for initializing JNI bindings.
struct RegistrationMethod {
const char* name;
bool (*func)(JNIEnv* env);
// Attaches the current thread to the VM (if necessary) and return the JNIEnv*.
BASE_EXPORT JNIEnv* AttachCurrentThread();
// Same to AttachCurrentThread except that thread name will be set to
// |thread_name| if it is the first call. Otherwise, thread_name won't be
// changed. AttachCurrentThread() doesn't regard underlying platform thread
// name, but just resets it to "Thread-???". This function should be called
// right after new thread is created if it is important to keep thread name.
BASE_EXPORT JNIEnv* AttachCurrentThreadWithName(const std::string& thread_name);
// Detaches the current thread from VM if it is attached.
BASE_EXPORT void DetachFromVM();
// Initializes the global JVM.
BASE_EXPORT void InitVM(JavaVM* vm);
// Returns true if the global JVM has been initialized.
BASE_EXPORT bool IsVMInitialized();
// Initializes the global ClassLoader used by the GetClass and LazyGetClass
// methods. This is needed because JNI will use the base ClassLoader when there
// is no Java code on the stack. The base ClassLoader doesn't know about any of
// the application classes and will fail to lookup anything other than system
// classes.
BASE_EXPORT void InitReplacementClassLoader(
JNIEnv* env,
const JavaRef<jobject>& class_loader);
// Finds the class named |class_name| and returns it.
// Use this method instead of invoking directly the JNI FindClass method (to
// prevent leaking local references).
// This method triggers a fatal assertion if the class could not be found.
// Use HasClass if you need to check whether the class exists.
BASE_EXPORT ScopedJavaLocalRef<jclass> GetClass(JNIEnv* env,
const char* class_name);
// The method will initialize |atomic_class_id| to contain a global ref to the
// class. And will return that ref on subsequent calls. It's the caller's
// responsibility to release the ref when it is no longer needed.
// The caller is responsible to zero-initialize |atomic_method_id|.
// It's fine to simultaneously call this on multiple threads referencing the
// same |atomic_method_id|.
BASE_EXPORT jclass LazyGetClass(
JNIEnv* env,
const char* class_name,
base::subtle::AtomicWord* atomic_class_id);
// This class is a wrapper for JNIEnv Get(Static)MethodID.
class BASE_EXPORT MethodID {
enum Type {
// Returns the method ID for the method with the specified name and signature.
// This method triggers a fatal assertion if the method could not be found.
template<Type type>
static jmethodID Get(JNIEnv* env,
jclass clazz,
const char* method_name,
const char* jni_signature);
// The caller is responsible to zero-initialize |atomic_method_id|.
// It's fine to simultaneously call this on multiple threads referencing the
// same |atomic_method_id|.
template<Type type>
static jmethodID LazyGet(JNIEnv* env,
jclass clazz,
const char* method_name,
const char* jni_signature,
base::subtle::AtomicWord* atomic_method_id);
// Returns true if an exception is pending in the provided JNIEnv*.
BASE_EXPORT bool HasException(JNIEnv* env);
// If an exception is pending in the provided JNIEnv*, this function clears it
// and returns true.
BASE_EXPORT bool ClearException(JNIEnv* env);
// This function will call CHECK() macro if there's any pending exception.
BASE_EXPORT void CheckException(JNIEnv* env);
// This returns a string representation of the java stack trace.
BASE_EXPORT std::string GetJavaExceptionInfo(JNIEnv* env,
jthrowable java_throwable);
// Saves caller's PC and stack frame in a thread-local variable.
// Implemented only when profiling is enabled (enable_profiling=true).
class BASE_EXPORT JNIStackFrameSaver {
JNIStackFrameSaver(void* current_fp);
static void* SavedFrame();
void* previous_fp_;
} // namespace android
} // namespace base