Repo created

TMessagesProj/jni/voip/webrtc/modules/utility/OWNERS

@@ -0,0 +1 @@
+perkj@webrtc.org

TMessagesProj/jni/voip/webrtc/modules/utility/include/helpers_android.h

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+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef MODULES_UTILITY_INCLUDE_HELPERS_ANDROID_H_
+#define MODULES_UTILITY_INCLUDE_HELPERS_ANDROID_H_
+
+#include <jni.h>
+
+#include <string>
+
+#include "rtc_base/system/arch.h"
+
+// Abort the process if `jni` has a Java exception pending.
+// TODO(henrika): merge with CHECK_JNI_EXCEPTION() in jni_helpers.h.
+#define CHECK_EXCEPTION(jni)        \
+  RTC_CHECK(!jni->ExceptionCheck()) \
+      << (jni->ExceptionDescribe(), jni->ExceptionClear(), "")
+
+#if defined(WEBRTC_ARCH_X86)
+// Dalvik JIT generated code doesn't guarantee 16-byte stack alignment on
+// x86 - use force_align_arg_pointer to realign the stack at the JNI
+// boundary. bugs.webrtc.org/9050
+#define JNI_FUNCTION_ALIGN __attribute__((force_align_arg_pointer))
+#else
+#define JNI_FUNCTION_ALIGN
+#endif
+
+namespace webrtc {
+
+// Return a |JNIEnv*| usable on this thread or NULL if this thread is detached.
+JNIEnv* GetEnv(JavaVM* jvm);
+
+// Return a `jlong` that will correctly convert back to `ptr`.  This is needed
+// because the alternative (of silently passing a 32-bit pointer to a vararg
+// function expecting a 64-bit param) picks up garbage in the high 32 bits.
+jlong PointerTojlong(void* ptr);
+
+// JNIEnv-helper methods that wraps the API which uses the JNI interface
+// pointer (JNIEnv*). It allows us to RTC_CHECK success and that no Java
+// exception is thrown while calling the method.
+jmethodID GetMethodID(JNIEnv* jni,
+                      jclass c,
+                      const char* name,
+                      const char* signature);
+
+jmethodID GetStaticMethodID(JNIEnv* jni,
+                            jclass c,
+                            const char* name,
+                            const char* signature);
+
+jclass FindClass(JNIEnv* jni, const char* name);
+
+jobject NewGlobalRef(JNIEnv* jni, jobject o);
+
+void DeleteGlobalRef(JNIEnv* jni, jobject o);
+
+// Attach thread to JVM if necessary and detach at scope end if originally
+// attached.
+class AttachThreadScoped {
+ public:
+  explicit AttachThreadScoped(JavaVM* jvm);
+  ~AttachThreadScoped();
+  JNIEnv* env();
+
+ private:
+  bool attached_;
+  JavaVM* jvm_;
+  JNIEnv* env_;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_UTILITY_INCLUDE_HELPERS_ANDROID_H_

TMessagesProj/jni/voip/webrtc/modules/utility/include/jvm_android.h

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+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef MODULES_UTILITY_INCLUDE_JVM_ANDROID_H_
+#define MODULES_UTILITY_INCLUDE_JVM_ANDROID_H_
+
+#include <jni.h>
+
+#include <memory>
+#include <string>
+#include <unordered_map>
+#include <thread>
+
+#include "api/sequence_checker.h"
+#include "modules/utility/include/helpers_android.h"
+
+namespace webrtc {
+
+// RAII JavaVM AttachCurrentThread/DetachCurrentThread object.
+//
+// The JNI interface pointer (JNIEnv) is valid only in the current thread.
+// Should another thread need to access the Java VM, it must first call
+// AttachCurrentThread() to attach itself to the VM and obtain a JNI interface
+// pointer. The native thread remains attached to the VM until it calls
+// DetachCurrentThread() to detach.
+class JvmThreadConnector {
+ public:
+  JvmThreadConnector();
+  ~JvmThreadConnector();
+
+ private:
+  SequenceChecker thread_checker_;
+};
+
+// This class is created by the NativeRegistration class and is used to wrap
+// the actual Java object handle (jobject) on which we can call methods from
+// C++ in to Java. See example in JVM for more details.
+// TODO(henrika): extend support for type of function calls.
+class GlobalRef {
+ public:
+  GlobalRef(JNIEnv* jni, jobject object);
+  ~GlobalRef();
+
+  jboolean CallBooleanMethod(jmethodID methodID, ...);
+  jint CallIntMethod(jmethodID methodID, ...);
+  void CallVoidMethod(jmethodID methodID, ...);
+
+ private:
+  JNIEnv* const jni_;
+  const jobject j_object_;
+};
+
+// Wraps the jclass object on which we can call GetMethodId() functions to
+// query method IDs.
+class JavaClass {
+ public:
+  JavaClass(JNIEnv* jni, jclass clazz) : jni_(jni), j_class_(clazz) {}
+  ~JavaClass() {}
+
+  jmethodID GetMethodId(const char* name, const char* signature);
+  jmethodID GetStaticMethodId(const char* name, const char* signature);
+  jobject CallStaticObjectMethod(jmethodID methodID, ...);
+  jint CallStaticIntMethod(jmethodID methodID, ...);
+
+ protected:
+  JNIEnv* const jni_;
+  jclass const j_class_;
+};
+
+// Adds support of the NewObject factory method to the JavaClass class.
+// See example in JVM for more details on how to use it.
+class NativeRegistration : public JavaClass {
+ public:
+  NativeRegistration(JNIEnv* jni, jclass clazz);
+  ~NativeRegistration();
+
+  std::unique_ptr<GlobalRef> NewObject(const char* name,
+                                       const char* signature,
+                                       ...);
+
+ private:
+  JNIEnv* const jni_;
+};
+
+// This class is created by the JVM class and is used to expose methods that
+// needs the JNI interface pointer but its main purpose is to create a
+// NativeRegistration object given name of a Java class and a list of native
+// methods. See example in JVM for more details.
+class JNIEnvironment {
+ public:
+  explicit JNIEnvironment(JNIEnv* jni);
+  ~JNIEnvironment();
+
+  // Registers native methods with the Java class specified by `name`.
+  // Note that the class name must be one of the names in the static
+  // `loaded_classes` array defined in jvm_android.cc.
+  // This method must be called on the construction thread.
+  std::unique_ptr<NativeRegistration> RegisterNatives(
+      const char* name,
+      const JNINativeMethod* methods,
+      int num_methods);
+
+  // Converts from Java string to std::string.
+  // This method must be called on the construction thread.
+  std::string JavaToStdString(const jstring& j_string);
+
+ private:
+  SequenceChecker thread_checker_;
+  JNIEnv* const jni_;
+};
+
+// Main class for working with Java from C++ using JNI in WebRTC.
+//
+// Example usage:
+//
+//   // At initialization (e.g. in JNI_OnLoad), call JVM::Initialize.
+//   JNIEnv* jni = ::base::android::AttachCurrentThread();
+//   JavaVM* jvm = NULL;
+//   jni->GetJavaVM(&jvm);
+//   webrtc::JVM::Initialize(jvm);
+//
+//   // Header (.h) file of example class called User.
+//   std::unique_ptr<JNIEnvironment> env;
+//   std::unique_ptr<NativeRegistration> reg;
+//   std::unique_ptr<GlobalRef> obj;
+//
+//   // Construction (in .cc file) of User class.
+//   User::User() {
+//     // Calling thread must be attached to the JVM.
+//     env = JVM::GetInstance()->environment();
+//     reg = env->RegisterNatives("org/webrtc/WebRtcTest", ,);
+//     obj = reg->NewObject("<init>", ,);
+//   }
+//
+//   // Each User method can now use `reg` and `obj` and call Java functions
+//   // in WebRtcTest.java, e.g. boolean init() {}.
+//   bool User::Foo() {
+//     jmethodID id = reg->GetMethodId("init", "()Z");
+//     return obj->CallBooleanMethod(id);
+//   }
+//
+//   // And finally, e.g. in JNI_OnUnLoad, call JVM::Uninitialize.
+//   JVM::Uninitialize();
+class JVM {
+ public:
+  // Stores global handles to the Java VM interface.
+  // Should be called once on a thread that is attached to the JVM.
+  static void Initialize(JavaVM* jvm);
+  // Like the method above but also passes the context to the ContextUtils
+  // class. This method should be used by pure-C++ Android users that can't call
+  // ContextUtils.initialize directly.
+  static void Initialize(JavaVM* jvm, jobject context);
+  // Clears handles stored in Initialize(). Must be called on same thread as
+  // Initialize().
+  static void Uninitialize();
+  // Gives access to the global Java VM interface pointer, which then can be
+  // used to create a valid JNIEnvironment object or to get a JavaClass object.
+  static JVM* GetInstance();
+
+  // Creates a JNIEnvironment object.
+  // This method returns a NULL pointer if AttachCurrentThread() has not been
+  // called successfully. Use the AttachCurrentThreadIfNeeded class if needed.
+  std::unique_ptr<JNIEnvironment> environment();
+
+  // Returns a JavaClass object given class `name`.
+  // Note that the class name must be one of the names in the static
+  // `loaded_classes` array defined in jvm_android.cc.
+  // This method must be called on the construction thread.
+  JavaClass GetClass(const char* name);
+
+  bool attachThread(std::thread::id id);
+  bool detachThread(std::thread::id id);
+
+  // TODO(henrika): can we make these private?
+  JavaVM* jvm() const { return jvm_; }
+
+ protected:
+  JVM(JavaVM* jvm);
+  ~JVM();
+
+ private:
+  JNIEnv* jni() const { return GetEnv(jvm_); }
+
+  SequenceChecker thread_checker_;
+  JavaVM* const jvm_;
+  std::unordered_map<std::thread::id, int> threadAttachCounts;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_UTILITY_INCLUDE_JVM_ANDROID_H_

TMessagesProj/jni/voip/webrtc/modules/utility/source/helpers_android.cc

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+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "modules/utility/include/helpers_android.h"
+
+#include <android/log.h>
+#include <pthread.h>
+#include <stddef.h>
+#include <unistd.h>
+
+#include "rtc_base/checks.h"
+#include "rtc_base/platform_thread.h"
+
+#define TAG "HelpersAndroid"
+#define ALOGD(...) __android_log_print(ANDROID_LOG_DEBUG, TAG, __VA_ARGS__)
+
+namespace webrtc {
+
+JNIEnv* GetEnv(JavaVM* jvm) {
+  void* env = NULL;
+  jint status = jvm->GetEnv(&env, JNI_VERSION_1_6);
+  RTC_CHECK(((env != NULL) && (status == JNI_OK)) ||
+            ((env == NULL) && (status == JNI_EDETACHED)))
+      << "Unexpected GetEnv return: " << status << ":" << env;
+  return reinterpret_cast<JNIEnv*>(env);
+}
+
+// Return a `jlong` that will correctly convert back to `ptr`.  This is needed
+// because the alternative (of silently passing a 32-bit pointer to a vararg
+// function expecting a 64-bit param) picks up garbage in the high 32 bits.
+jlong PointerTojlong(void* ptr) {
+  static_assert(sizeof(intptr_t) <= sizeof(jlong),
+                "Time to rethink the use of jlongs");
+  // Going through intptr_t to be obvious about the definedness of the
+  // conversion from pointer to integral type.  intptr_t to jlong is a standard
+  // widening by the static_assert above.
+  jlong ret = reinterpret_cast<intptr_t>(ptr);
+  RTC_DCHECK(reinterpret_cast<void*>(ret) == ptr);
+  return ret;
+}
+
+jmethodID GetMethodID(JNIEnv* jni,
+                      jclass c,
+                      const char* name,
+                      const char* signature) {
+  jmethodID m = jni->GetMethodID(c, name, signature);
+  CHECK_EXCEPTION(jni) << "Error during GetMethodID: " << name << ", "
+                       << signature;
+  RTC_CHECK(m) << name << ", " << signature;
+  return m;
+}
+
+jmethodID GetStaticMethodID(JNIEnv* jni,
+                            jclass c,
+                            const char* name,
+                            const char* signature) {
+  jmethodID m = jni->GetStaticMethodID(c, name, signature);
+  CHECK_EXCEPTION(jni) << "Error during GetStaticMethodID: " << name << ", "
+                       << signature;
+  RTC_CHECK(m) << name << ", " << signature;
+  return m;
+}
+
+jclass FindClass(JNIEnv* jni, const char* name) {
+  jclass c = jni->FindClass(name);
+  CHECK_EXCEPTION(jni) << "Error during FindClass: " << name;
+  RTC_CHECK(c) << name;
+  return c;
+}
+
+jobject NewGlobalRef(JNIEnv* jni, jobject o) {
+  jobject ret = jni->NewGlobalRef(o);
+  CHECK_EXCEPTION(jni) << "Error during NewGlobalRef";
+  RTC_CHECK(ret);
+  return ret;
+}
+
+void DeleteGlobalRef(JNIEnv* jni, jobject o) {
+  jni->DeleteGlobalRef(o);
+  CHECK_EXCEPTION(jni) << "Error during DeleteGlobalRef";
+}
+
+AttachThreadScoped::AttachThreadScoped(JavaVM* jvm)
+    : attached_(false), jvm_(jvm), env_(NULL) {
+  env_ = GetEnv(jvm);
+  if (!env_) {
+    // Adding debug log here so we can track down potential leaks and figure
+    // out why we sometimes see "Native thread exiting without having called
+    // DetachCurrentThread" in logcat outputs.
+    ALOGD("Attaching thread to JVM[tid=%d]", rtc::CurrentThreadId());
+    jint res = jvm->AttachCurrentThread(&env_, NULL);
+    attached_ = (res == JNI_OK);
+    RTC_CHECK(attached_) << "AttachCurrentThread failed: " << res;
+  }
+}
+
+AttachThreadScoped::~AttachThreadScoped() {
+  if (attached_) {
+    ALOGD("Detaching thread from JVM[tid=%d]", rtc::CurrentThreadId());
+    jint res = jvm_->DetachCurrentThread();
+    RTC_CHECK(res == JNI_OK) << "DetachCurrentThread failed: " << res;
+    RTC_CHECK(!GetEnv(jvm_));
+  }
+}
+
+JNIEnv* AttachThreadScoped::env() {
+  return env_;
+}
+
+}  // namespace webrtc

TMessagesProj/jni/voip/webrtc/modules/utility/source/jvm_android.cc

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+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "modules/utility/include/jvm_android.h"
+
+#include <android/log.h>
+
+#include <memory>
+
+#include "rtc_base/checks.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/platform_thread.h"
+#include "tgnet/FileLog.h"
+
+namespace webrtc {
+
+JVM* g_jvm;
+
+// TODO(henrika): add more clases here if needed.
+struct {
+  const char* name;
+  jclass clazz;
+} loaded_classes[] = {
+    {"org/webrtc/voiceengine/BuildInfo", nullptr},
+    {"org/webrtc/voiceengine/WebRtcAudioManager", nullptr},
+    {"org/webrtc/voiceengine/WebRtcAudioRecord", nullptr},
+    {"org/webrtc/voiceengine/WebRtcAudioTrack", nullptr},
+};
+
+// Android's FindClass() is trickier than usual because the app-specific
+// ClassLoader is not consulted when there is no app-specific frame on the
+// stack.  Consequently, we only look up all classes once in native WebRTC.
+// http://developer.android.com/training/articles/perf-jni.html#faq_FindClass
+void LoadClasses(JNIEnv* jni) {
+  RTC_LOG(LS_INFO) << "LoadClasses:";
+  for (auto& c : loaded_classes) {
+    jclass localRef = FindClass(jni, c.name);
+    RTC_LOG(LS_INFO) << "name: " << c.name;
+    CHECK_EXCEPTION(jni) << "Error during FindClass: " << c.name;
+    RTC_CHECK(localRef) << c.name;
+    DEBUG_REF("webrtc 4 globalref");
+    jclass globalRef = reinterpret_cast<jclass>(jni->NewGlobalRef(localRef));
+    CHECK_EXCEPTION(jni) << "Error during NewGlobalRef: " << c.name;
+    RTC_CHECK(globalRef) << c.name;
+    c.clazz = globalRef;
+  }
+}
+
+void FreeClassReferences(JNIEnv* jni) {
+  for (auto& c : loaded_classes) {
+    DEBUG_DELREF("FreeClassReferences");
+    jni->DeleteGlobalRef(c.clazz);
+    c.clazz = nullptr;
+  }
+}
+
+jclass LookUpClass(const char* name) {
+  for (auto& c : loaded_classes) {
+    if (strcmp(c.name, name) == 0)
+      return c.clazz;
+  }
+  RTC_CHECK(false) << "Unable to find class in lookup table";
+  return 0;
+}
+
+// JvmThreadConnector implementation.
+JvmThreadConnector::JvmThreadConnector() {
+  RTC_LOG(LS_INFO) << "JvmThreadConnector::ctor";
+  JavaVM* jvm = JVM::GetInstance()->jvm();
+  RTC_CHECK(jvm);
+  JNIEnv* jni = GetEnv(jvm);
+  if (JVM::GetInstance()->attachThread(std::this_thread::get_id())) {
+    RTC_LOG(LS_INFO) << "Attaching thread to JVM";
+    JNIEnv* env = nullptr;
+    jint ret = jvm->AttachCurrentThread(&env, nullptr);
+  }
+}
+
+JvmThreadConnector::~JvmThreadConnector() {
+  RTC_LOG(LS_INFO) << "JvmThreadConnector::dtor";
+  RTC_DCHECK(thread_checker_.IsCurrent());
+  if (JVM::GetInstance()->detachThread(std::this_thread::get_id())) {
+    RTC_LOG(LS_INFO) << "Detaching thread from JVM";
+    jint res = JVM::GetInstance()->jvm()->DetachCurrentThread();
+    RTC_CHECK(res == JNI_OK) << "DetachCurrentThread failed: " << res;
+  }
+}
+
+// GlobalRef implementation.
+GlobalRef::GlobalRef(JNIEnv* jni, jobject object)
+    : jni_(jni), j_object_(NewGlobalRef(jni, object)) {
+  DEBUG_REF("webrtc jvm globalref");
+  RTC_LOG(LS_INFO) << "GlobalRef::ctor";
+}
+
+GlobalRef::~GlobalRef() {
+  RTC_LOG(LS_INFO) << "GlobalRef::dtor";
+  DEBUG_DELREF("webrtc jvm globalref");
+  DeleteGlobalRef(jni_, j_object_);
+}
+
+jboolean GlobalRef::CallBooleanMethod(jmethodID methodID, ...) {
+  va_list args;
+  va_start(args, methodID);
+  jboolean res = jni_->CallBooleanMethodV(j_object_, methodID, args);
+  CHECK_EXCEPTION(jni_) << "Error during CallBooleanMethod";
+  va_end(args);
+  return res;
+}
+
+jint GlobalRef::CallIntMethod(jmethodID methodID, ...) {
+  va_list args;
+  va_start(args, methodID);
+  jint res = jni_->CallIntMethodV(j_object_, methodID, args);
+  CHECK_EXCEPTION(jni_) << "Error during CallIntMethod";
+  va_end(args);
+  return res;
+}
+
+void GlobalRef::CallVoidMethod(jmethodID methodID, ...) {
+  va_list args;
+  va_start(args, methodID);
+  jni_->CallVoidMethodV(j_object_, methodID, args);
+  CHECK_EXCEPTION(jni_) << "Error during CallVoidMethod";
+  va_end(args);
+}
+
+// NativeRegistration implementation.
+NativeRegistration::NativeRegistration(JNIEnv* jni, jclass clazz)
+    : JavaClass(jni, clazz), jni_(jni) {
+  RTC_LOG(LS_INFO) << "NativeRegistration::ctor";
+}
+
+NativeRegistration::~NativeRegistration() {
+  RTC_LOG(LS_INFO) << "NativeRegistration::dtor";
+  // jni_->UnregisterNatives(j_class_);
+  CHECK_EXCEPTION(jni_) << "Error during UnregisterNatives";
+}
+
+std::unique_ptr<GlobalRef> NativeRegistration::NewObject(const char* name,
+                                                         const char* signature,
+                                                         ...) {
+  RTC_LOG(LS_INFO) << "NativeRegistration::NewObject";
+  va_list args;
+  va_start(args, signature);
+  jobject obj = jni_->NewObjectV(
+      j_class_, GetMethodID(jni_, j_class_, name, signature), args);
+  CHECK_EXCEPTION(jni_) << "Error during NewObjectV";
+  va_end(args);
+  return std::unique_ptr<GlobalRef>(new GlobalRef(jni_, obj));
+}
+
+// JavaClass implementation.
+jmethodID JavaClass::GetMethodId(const char* name, const char* signature) {
+  return GetMethodID(jni_, j_class_, name, signature);
+}
+
+jmethodID JavaClass::GetStaticMethodId(const char* name,
+                                       const char* signature) {
+  return GetStaticMethodID(jni_, j_class_, name, signature);
+}
+
+jobject JavaClass::CallStaticObjectMethod(jmethodID methodID, ...) {
+  va_list args;
+  va_start(args, methodID);
+  jobject res = jni_->CallStaticObjectMethodV(j_class_, methodID, args);
+  CHECK_EXCEPTION(jni_) << "Error during CallStaticObjectMethod";
+  return res;
+}
+
+jint JavaClass::CallStaticIntMethod(jmethodID methodID, ...) {
+  va_list args;
+  va_start(args, methodID);
+  jint res = jni_->CallStaticIntMethodV(j_class_, methodID, args);
+  CHECK_EXCEPTION(jni_) << "Error during CallStaticIntMethod";
+  return res;
+}
+
+// JNIEnvironment implementation.
+JNIEnvironment::JNIEnvironment(JNIEnv* jni) : jni_(jni) {
+  RTC_LOG(LS_INFO) << "JNIEnvironment::ctor";
+}
+
+JNIEnvironment::~JNIEnvironment() {
+  RTC_LOG(LS_INFO) << "JNIEnvironment::dtor";
+  RTC_DCHECK(thread_checker_.IsCurrent());
+}
+
+std::unique_ptr<NativeRegistration> JNIEnvironment::RegisterNatives(
+    const char* name,
+    const JNINativeMethod* methods,
+    int num_methods) {
+  RTC_LOG(LS_INFO) << "JNIEnvironment::RegisterNatives: " << name;
+  RTC_DCHECK(thread_checker_.IsCurrent());
+  jclass clazz = LookUpClass(name);
+  jni_->RegisterNatives(clazz, methods, num_methods);
+  CHECK_EXCEPTION(jni_) << "Error during RegisterNatives";
+  return std::unique_ptr<NativeRegistration>(
+      new NativeRegistration(jni_, clazz));
+}
+
+std::string JNIEnvironment::JavaToStdString(const jstring& j_string) {
+  RTC_DCHECK(thread_checker_.IsCurrent());
+  const char* jchars = jni_->GetStringUTFChars(j_string, nullptr);
+  CHECK_EXCEPTION(jni_);
+  const int size = jni_->GetStringUTFLength(j_string);
+  CHECK_EXCEPTION(jni_);
+  std::string ret(jchars, size);
+  jni_->ReleaseStringUTFChars(j_string, jchars);
+  CHECK_EXCEPTION(jni_);
+  return ret;
+}
+
+// static
+void JVM::Initialize(JavaVM* jvm) {
+  RTC_LOG(LS_INFO) << "JVM::Initialize";
+  RTC_CHECK(!g_jvm);
+  g_jvm = new JVM(jvm);
+}
+
+void JVM::Initialize(JavaVM* jvm, jobject context) {
+  Initialize(jvm);
+
+  // Pass in the context to the new ContextUtils class.
+  JNIEnv* jni = g_jvm->jni();
+  jclass context_utils = FindClass(jni, "org/webrtc/ContextUtils");
+  jmethodID initialize_method = jni->GetStaticMethodID(
+      context_utils, "initialize", "(Landroid/content/Context;)V");
+  jni->CallStaticVoidMethod(context_utils, initialize_method, context);
+}
+
+// static
+void JVM::Uninitialize() {
+  RTC_LOG(LS_INFO) << "JVM::Uninitialize";
+  RTC_DCHECK(g_jvm);
+  delete g_jvm;
+  g_jvm = nullptr;
+}
+
+// static
+JVM* JVM::GetInstance() {
+  RTC_DCHECK(g_jvm);
+  return g_jvm;
+}
+
+JVM::JVM(JavaVM* jvm) : jvm_(jvm) {
+  RTC_LOG(LS_INFO) << "JVM::JVM";
+  RTC_CHECK(jni()) << "AttachCurrentThread() must be called on this thread.";
+  LoadClasses(jni());
+}
+
+JVM::~JVM() {
+  RTC_LOG(LS_INFO) << "JVM::~JVM";
+  RTC_DCHECK(thread_checker_.IsCurrent());
+  FreeClassReferences(jni());
+}
+
+std::unique_ptr<JNIEnvironment> JVM::environment() {
+  RTC_LOG(LS_INFO) << "JVM::environment";
+  ;
+  // The JNIEnv is used for thread-local storage. For this reason, we cannot
+  // share a JNIEnv between threads. If a piece of code has no other way to get
+  // its JNIEnv, we should share the JavaVM, and use GetEnv to discover the
+  // thread's JNIEnv. (Assuming it has one, if not, use AttachCurrentThread).
+  // See // http://developer.android.com/training/articles/perf-jni.html.
+  JNIEnv* jni = GetEnv(jvm_);
+  if (!jni) {
+    RTC_LOG(LS_ERROR)
+        << "AttachCurrentThread() has not been called on this thread";
+    return std::unique_ptr<JNIEnvironment>();
+  }
+  return std::unique_ptr<JNIEnvironment>(new JNIEnvironment(jni));
+}
+
+JavaClass JVM::GetClass(const char* name) {
+  RTC_LOG(LS_INFO) << "JVM::GetClass: " << name;
+  RTC_DCHECK(thread_checker_.IsCurrent());
+  return JavaClass(jni(), LookUpClass(name));
+}
+
+bool JVM::attachThread(std::thread::id id) {
+    auto& count = threadAttachCounts[id];
+    bool first = count == 0;
+    ++count;
+    return first;
+}
+
+bool JVM::detachThread(std::thread::id id) {
+    auto& count = threadAttachCounts[id];
+    count = count - 1;
+    if (count < 0) count = 0;
+    return count == 0;
+}
+
+}  // namespace webrtc