Add libbinderwrapper.

Add a library that wraps libbinder to make it possible to
write tests for native code that communicates via binder.

Bug: 23791723
Change-Id: I3c842413e0f07dc252040c042d664031b0354353

include/binderwrapper/binder_test_base.h

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SYSTEM_CORE_INCLUDE_BINDERWRAPPER_BINDER_TEST_BASE_H_
+#define SYSTEM_CORE_INCLUDE_BINDERWRAPPER_BINDER_TEST_BASE_H_
+
+#include <base/macros.h>
+#include <gtest/gtest.h>
+
+namespace android {
+
+class StubBinderWrapper;
+
+// Class that can be inherited from (or aliased via typedef/using) when writing
+// tests that use StubBinderManager.
+class BinderTestBase : public ::testing::Test {
+ public:
+  BinderTestBase();
+  ~BinderTestBase() override;
+
+  StubBinderWrapper* binder_wrapper() { return binder_wrapper_; }
+
+ protected:
+  StubBinderWrapper* binder_wrapper_;  // Not owned.
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BinderTestBase);
+};
+
+}  // namespace android
+
+#endif  // SYSTEM_CORE_INCLUDE_BINDERWRAPPER_BINDER_TEST_BASE_H_

include/binderwrapper/binder_wrapper.h

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SYSTEM_CORE_INCLUDE_BINDERWRAPPER_BINDER_WRAPPER_H_
+#define SYSTEM_CORE_INCLUDE_BINDERWRAPPER_BINDER_WRAPPER_H_
+
+#include <string>
+
+#include <base/callback.h>
+#include <utils/StrongPointer.h>
+
+namespace android {
+
+class BBinder;
+class IBinder;
+
+// Wraps libbinder to make it testable.
+class BinderWrapper {
+ public:
+  virtual ~BinderWrapper() {}
+
+  // Creates and initializes the singleton (using a wrapper that communicates
+  // with the real binder system).
+  static void Create();
+
+  // Initializes |wrapper| as the singleton, taking ownership of it. Tests that
+  // want to inject their own wrappers should call this instead of Create().
+  static void InitForTesting(BinderWrapper* wrapper);
+
+  // Destroys the singleton. Must be called before calling Create() or
+  // InitForTesting() a second time.
+  static void Destroy();
+
+  // Returns the singleton instance previously created by Create() or set by
+  // InitForTesting().
+  static BinderWrapper* Get();
+
+  // Gets the binder for communicating with the service identified by
+  // |service_name|, returning null immediately if it doesn't exist.
+  virtual sp<IBinder> GetService(const std::string& service_name) = 0;
+
+  // Registers |binder| as |service_name| with the service manager.
+  virtual bool RegisterService(const std::string& service_name,
+                               const sp<IBinder>& binder) = 0;
+
+  // Creates a local binder object.
+  virtual sp<BBinder> CreateLocalBinder() = 0;
+
+  // Registers |callback| to be invoked when |binder| dies. If another callback
+  // is currently registered for |binder|, it will be replaced.
+  virtual bool RegisterForDeathNotifications(
+      const sp<IBinder>& binder,
+      const base::Closure& callback) = 0;
+
+  // Unregisters the callback, if any, for |binder|.
+  virtual bool UnregisterForDeathNotifications(const sp<IBinder>& binder) = 0;
+
+ private:
+  static BinderWrapper* instance_;
+};
+
+}  // namespace android
+
+#endif  // SYSTEM_CORE_INCLUDE_BINDERWRAPPER_BINDER_WRAPPER_H_

include/binderwrapper/stub_binder_wrapper.h

@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SYSTEM_CORE_INCLUDE_BINDERWRAPPER_STUB_BINDER_WRAPPER_H_
+#define SYSTEM_CORE_INCLUDE_BINDERWRAPPER_STUB_BINDER_WRAPPER_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include <base/macros.h>
+#include <binder/Binder.h>
+#include <binder/IBinder.h>
+#include <binderwrapper/binder_wrapper.h>
+
+namespace android {
+
+// Stub implementation of BinderWrapper for testing.
+//
+// Example usage:
+//
+// First, assuming a base IFoo binder interface, create a stub class that
+// derives from BnFoo to implement the receiver side of the communication:
+//
+//   class StubFoo : public BnFoo {
+//    public:
+//     ...
+//     status_t doSomething(int arg) override {
+//       // e.g. save passed-in value for later inspection by tests.
+//       return OK;
+//     }
+//   };
+//
+// Next, from your test code, inject a StubBinderManager either directly or by
+// inheriting from the BinderTestBase class:
+//
+//   StubBinderWrapper* wrapper = new StubBinderWrapper();
+//   BinderWrapper::InitForTesting(wrapper);  // Takes ownership.
+//
+// Also from your test, create a StubFoo and register it with the wrapper:
+//
+//   StubFoo* foo = new StubFoo();
+//   sp<IBinder> binder(foo);
+//   wrapper->SetBinderForService("foo", binder);
+//
+// The code being tested can now use the wrapper to get the stub and call it:
+//
+//   sp<IBinder> binder = BinderWrapper::Get()->GetService("foo");
+//   CHECK(binder.get());
+//   sp<IFoo> foo = interface_cast<IFoo>(binder);
+//   CHECK_EQ(foo->doSomething(3), OK);
+//
+// To create a local BBinder object, production code can call
+// CreateLocalBinder(). Then, a test can get the BBinder's address via
+// local_binders() to check that they're passed as expected in binder calls.
+//
+class StubBinderWrapper : public BinderWrapper {
+ public:
+  StubBinderWrapper();
+  ~StubBinderWrapper() override;
+
+  const std::vector<sp<BBinder>>& local_binders() const {
+    return local_binders_;
+  }
+  void clear_local_binders() { local_binders_.clear(); }
+
+  // Sets the binder to return when |service_name| is passed to GetService() or
+  // WaitForService().
+  void SetBinderForService(const std::string& service_name,
+                           const sp<IBinder>& binder);
+
+  // Returns the binder previously registered for |service_name| via
+  // RegisterService(), or null if the service hasn't been registered.
+  sp<IBinder> GetRegisteredService(const std::string& service_name) const;
+
+  // Run the calback in |death_callbacks_| corresponding to |binder|.
+  void NotifyAboutBinderDeath(const sp<IBinder>& binder);
+
+  // BinderWrapper:
+  sp<IBinder> GetService(const std::string& service_name) override;
+  bool RegisterService(const std::string& service_name,
+                       const sp<IBinder>& binder) override;
+  sp<BBinder> CreateLocalBinder() override;
+  bool RegisterForDeathNotifications(const sp<IBinder>& binder,
+                                     const base::Closure& callback) override;
+  bool UnregisterForDeathNotifications(const sp<IBinder>& binder) override;
+
+ private:
+  using ServiceMap = std::map<std::string, sp<IBinder>>;
+
+  // Map from service name to associated binder handle. Used by GetService() and
+  // WaitForService().
+  ServiceMap services_to_return_;
+
+  // Map from service name to associated binder handle. Updated by
+  // RegisterService().
+  ServiceMap registered_services_;
+
+  // Local binders returned by CreateLocalBinder().
+  std::vector<sp<BBinder>> local_binders_;
+
+  // Map from binder handle to the callback that should be invoked on binder
+  // death.
+  std::map<sp<IBinder>, base::Closure> death_callbacks_;
+
+  DISALLOW_COPY_AND_ASSIGN(StubBinderWrapper);
+};
+
+}  // namespace android
+
+#endif  // SYSTEM_CORE_INCLUDE_BINDERWRAPPER_STUB_BINDER_WRAPPER_H_

libbinderwrapper/Android.mk

@@ -0,0 +1,62 @@
+#
+# Copyright (C) 2015 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+LOCAL_PATH := $(call my-dir)
+
+binderwrapperCommonCFlags := -Wall -Werror -Wno-unused-parameter
+binderwrapperCommonCFlags += -Wno-sign-promo  # for libchrome
+binderwrapperCommonExportCIncludeDirs := $(LOCAL_PATH)/../include
+binderwrapperCommonCIncludes := $(LOCAL_PATH)/../include
+binderwrapperCommonSharedLibraries := \
+  libbinder \
+  libchrome \
+  libutils \
+
+# libbinderwrapper shared library
+# ========================================================
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := libbinderwrapper
+LOCAL_CPP_EXTENSION := .cc
+LOCAL_CFLAGS := $(binderwrapperCommonCFlags)
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(binderwrapperCommonExportCIncludeDirs)
+LOCAL_C_INCLUDES := $(binderwrapperCommonCIncludes)
+LOCAL_SHARED_LIBRARIES := $(binderwrapperCommonSharedLibraries)
+LOCAL_SRC_FILES := \
+  binder_wrapper.cc \
+  real_binder_wrapper.cc \
+
+include $(BUILD_SHARED_LIBRARY)
+
+# libbinderwrapper_test_support shared library
+# ========================================================
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := libbinderwrapper_test_support
+LOCAL_CPP_EXTENSION := .cc
+LOCAL_CFLAGS := $(binderwrapperCommonCFlags)
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(binderwrapperCommonExportCIncludeDirs)
+LOCAL_C_INCLUDES := $(binderwrapperCommonCIncludes)
+LOCAL_STATIC_LIBRARIES := libgtest
+LOCAL_SHARED_LIBRARIES := \
+  $(binderwrapperCommonSharedLibraries) \
+  libbinderwrapper \
+
+LOCAL_SRC_FILES := \
+  binder_test_base.cc \
+  stub_binder_wrapper.cc \
+
+include $(BUILD_SHARED_LIBRARY)

libbinderwrapper/binder_test_base.cc

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <binderwrapper/binder_test_base.h>
+
+#include <binderwrapper/binder_wrapper.h>
+#include <binderwrapper/stub_binder_wrapper.h>
+
+namespace android {
+
+BinderTestBase::BinderTestBase() : binder_wrapper_(new StubBinderWrapper()) {
+  // Pass ownership.
+  BinderWrapper::InitForTesting(binder_wrapper_);
+}
+
+BinderTestBase::~BinderTestBase() {
+  BinderWrapper::Destroy();
+}
+
+}  // namespace android

libbinderwrapper/binder_wrapper.cc

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <binderwrapper/binder_wrapper.h>
+
+#include <base/logging.h>
+
+#include "real_binder_wrapper.h"
+
+namespace android {
+
+// Singleton instance.
+BinderWrapper* BinderWrapper::instance_ = nullptr;
+
+// static
+void BinderWrapper::Create() {
+  CHECK(!instance_) << "Already initialized; missing call to Destroy()?";
+  instance_ = new RealBinderWrapper();
+}
+
+// static
+void BinderWrapper::InitForTesting(BinderWrapper* wrapper) {
+  CHECK(!instance_) << "Already initialized; missing call to Destroy()?";
+  instance_ = wrapper;
+}
+
+// static
+void BinderWrapper::Destroy() {
+  CHECK(instance_) << "Not initialized; missing call to Create()?";
+  delete instance_;
+  instance_ = nullptr;
+}
+
+// static
+BinderWrapper* BinderWrapper::Get() {
+  CHECK(instance_) << "Not initialized; missing call to Create()?";
+  return instance_;
+}
+
+}  // namespace android

libbinderwrapper/real_binder_wrapper.cc

@@ -0,0 +1,114 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "real_binder_wrapper.h"
+
+#include <base/logging.h>
+#include <binder/Binder.h>
+#include <binder/IBinder.h>
+#include <binder/IServiceManager.h>
+
+namespace android {
+
+// Class that handles binder death notifications. libbinder wants the recipient
+// to be wrapped in sp<>, so registering RealBinderWrapper as a recipient would
+// be awkward.
+class RealBinderWrapper::DeathRecipient : public IBinder::DeathRecipient {
+ public:
+  explicit DeathRecipient(const base::Closure& callback)
+      : callback_(callback) {}
+  ~DeathRecipient() = default;
+
+  // IBinder::DeathRecipient:
+  void binderDied(const wp<IBinder>& who) override {
+    callback_.Run();
+  }
+
+ private:
+  // Callback to run in response to binder death.
+  base::Closure callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(DeathRecipient);
+};
+
+RealBinderWrapper::RealBinderWrapper() = default;
+
+RealBinderWrapper::~RealBinderWrapper() = default;
+
+sp<IBinder> RealBinderWrapper::GetService(const std::string& service_name) {
+  sp<IServiceManager> service_manager = defaultServiceManager();
+  if (!service_manager.get()) {
+    LOG(ERROR) << "Unable to get service manager";
+    return sp<IBinder>();
+  }
+  sp<IBinder> binder =
+      service_manager->checkService(String16(service_name.c_str()));
+  if (!binder.get())
+    LOG(ERROR) << "Unable to get \"" << service_name << "\" service";
+  return binder;
+}
+
+bool RealBinderWrapper::RegisterService(const std::string& service_name,
+                                        const sp<IBinder>& binder) {
+  sp<IServiceManager> service_manager = defaultServiceManager();
+  if (!service_manager.get()) {
+    LOG(ERROR) << "Unable to get service manager";
+    return false;
+  }
+  status_t status = defaultServiceManager()->addService(
+      String16(service_name.c_str()), binder);
+  if (status != OK) {
+    LOG(ERROR) << "Failed to register \"" << service_name << "\" with service "
+               << "manager";
+    return false;
+  }
+  return true;
+}
+
+sp<BBinder> RealBinderWrapper::CreateLocalBinder() {
+  return sp<BBinder>(new BBinder());
+}
+
+bool RealBinderWrapper::RegisterForDeathNotifications(
+    const sp<IBinder>& binder,
+    const base::Closure& callback) {
+  sp<DeathRecipient> recipient(new DeathRecipient(callback));
+  if (binder->linkToDeath(recipient) != OK) {
+    LOG(ERROR) << "Failed to register for death notifications on "
+               << binder.get();
+    return false;
+  }
+  death_recipients_[binder] = recipient;
+  return true;
+}
+
+bool RealBinderWrapper::UnregisterForDeathNotifications(
+    const sp<IBinder>& binder) {
+  auto it = death_recipients_.find(binder);
+  if (it == death_recipients_.end()) {
+    LOG(ERROR) << "Not registered for death notifications on " << binder.get();
+    return false;
+  }
+  if (binder->unlinkToDeath(it->second) != OK) {
+    LOG(ERROR) << "Failed to unregister for death notifications on "
+               << binder.get();
+    return false;
+  }
+  death_recipients_.erase(it);
+  return true;
+}
+
+}  // namespace android

libbinderwrapper/real_binder_wrapper.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SYSTEM_CORE_LIBBINDERWRAPPER_REAL_BINDER_WRAPPER_H_
+#define SYSTEM_CORE_LIBBINDERWRAPPER_REAL_BINDER_WRAPPER_H_
+
+#include <base/macros.h>
+#include <binderwrapper/binder_wrapper.h>
+
+namespace android {
+
+class IBinder;
+
+// Real implementation of BinderWrapper.
+class RealBinderWrapper : public BinderWrapper {
+ public:
+  RealBinderWrapper();
+  ~RealBinderWrapper() override;
+
+  // BinderWrapper:
+  sp<IBinder> GetService(const std::string& service_name) override;
+  bool RegisterService(const std::string& service_name,
+                       const sp<IBinder>& binder) override;
+  sp<BBinder> CreateLocalBinder() override;
+  bool RegisterForDeathNotifications(const sp<IBinder>& binder,
+                                     const base::Closure& callback) override;
+  bool UnregisterForDeathNotifications(const sp<IBinder>& binder) override;
+
+ private:
+  class DeathRecipient;
+
+  // Map from binder handle to object that should be notified of the binder's
+  // death.
+  std::map<sp<IBinder>, sp<DeathRecipient>> death_recipients_;
+
+  DISALLOW_COPY_AND_ASSIGN(RealBinderWrapper);
+};
+
+}  // namespace android
+
+#endif  // SYSTEM_CORE_LIBBINDER_WRAPPER_REAL_BINDER_WRAPPER_H_

libbinderwrapper/stub_binder_wrapper.cc

@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <binderwrapper/stub_binder_wrapper.h>
+
+#include <base/logging.h>
+#include <binder/Binder.h>
+#include <binder/IBinder.h>
+
+namespace android {
+
+StubBinderWrapper::StubBinderWrapper() = default;
+
+StubBinderWrapper::~StubBinderWrapper() = default;
+
+void StubBinderWrapper::SetBinderForService(const std::string& service_name,
+                                            const sp<IBinder>& binder) {
+  services_to_return_[service_name] = binder;
+}
+
+sp<IBinder> StubBinderWrapper::GetRegisteredService(
+    const std::string& service_name) const {
+  const auto it = registered_services_.find(service_name);
+  return it != registered_services_.end() ? it->second : sp<IBinder>();
+}
+
+void StubBinderWrapper::NotifyAboutBinderDeath(const sp<IBinder>& binder) {
+  const auto it = death_callbacks_.find(binder);
+  if (it != death_callbacks_.end())
+    it->second.Run();
+}
+
+sp<IBinder> StubBinderWrapper::GetService(const std::string& service_name) {
+  const auto it = services_to_return_.find(service_name);
+  return it != services_to_return_.end() ? it->second : sp<IBinder>();
+}
+
+bool StubBinderWrapper::RegisterService(const std::string& service_name,
+                                        const sp<IBinder>& binder) {
+  registered_services_[service_name] = binder;
+  return true;
+}
+
+sp<BBinder> StubBinderWrapper::CreateLocalBinder() {
+  sp<BBinder> binder(new BBinder());
+  local_binders_.push_back(binder);
+  return binder;
+}
+
+bool StubBinderWrapper::RegisterForDeathNotifications(
+    const sp<IBinder>& binder,
+    const base::Closure& callback) {
+  death_callbacks_[binder] = callback;
+  return true;
+}
+
+bool StubBinderWrapper::UnregisterForDeathNotifications(
+    const sp<IBinder>& binder) {
+  death_callbacks_.erase(binder);
+  return true;
+}
+
+}  // namespace android