Roll forward to cl/314747126

Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: Ie19e006429b138b3768e97dae971a43fdc5ef8bf

cpp/platform/impl/shared/BUILD

@@ -0,0 +1,87 @@
+# Copyright 2020 Google LLC
+#
+# 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
+#
+#     https://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.
+
+cc_library(
+    name = "posix_lock",
+    srcs = [
+        "posix_lock.cc",
+    ],
+    hdrs = [
+        "posix_lock.h",
+    ],
+    visibility = [
+        "//googlemac/iPhone/Shared/Nearby/Connections:__subpackages__",
+        "//platform/impl:__subpackages__",
+    ],
+    deps = [
+        "//platform/api",
+    ],
+)
+
+cc_library(
+    name = "posix_condition_variable",
+    srcs = [
+        "posix_condition_variable.cc",
+    ],
+    hdrs = [
+        "posix_condition_variable.h",
+    ],
+    visibility = [
+        "//googlemac/iPhone/Shared/Nearby/Connections:__subpackages__",
+        "//platform/impl:__subpackages__",
+    ],
+    deps = [
+        ":posix_lock",
+        "//platform:types",
+        "//platform/api:condition_variable",
+    ],
+)
+
+cc_library(
+    name = "atomic_boolean",
+    hdrs = ["atomic_boolean_impl.h"],
+    visibility = [
+        "//googlemac/iPhone/Shared/Nearby/Connections:__subpackages__",
+        "//platform/impl:__subpackages__",
+    ],
+    deps = ["//platform/api"],
+)
+
+cc_library(
+    name = "file",
+    srcs = ["file_impl.cc"],
+    hdrs = ["file_impl.h"],
+    visibility = [
+        "//googlemac/iPhone/Shared/Nearby/Connections:__subpackages__",
+        "//core:__subpackages__",
+        "//platform/impl:__subpackages__",
+    ],
+    deps = [
+        "//platform:types",
+        "//platform/api",
+    ],
+)
+
+cc_test(
+    name = "file_test",
+    timeout = "short",
+    srcs = [
+        "file_impl_test.cc",
+    ],
+    deps = [
+        ":file",
+        "//file/util:temp_path",
+        "//testing/base/public:gunit_main",
+    ],
+)

cpp/platform/impl/shared/CMakeLists.txt

@@ -0,0 +1,101 @@
+# Copyright 2020 Google LLC
+#
+# 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
+#
+#     https://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.
+
+add_library(platform_impl_shared_posix_lock STATIC)
+
+target_sources(platform_impl_shared_posix_lock
+  PRIVATE
+    "posix_lock.cc"
+  PUBLIC
+    "posix_lock.h"
+)
+
+target_include_directories(platform_impl_shared_posix_lock
+  PUBLIC
+    ${CMAKE_CURRENT_SOURCE_DIR}
+)
+
+
+target_link_libraries(platform_impl_shared_posix_lock
+  PUBLIC
+    platform_api
+    platform_types
+)
+
+add_library(platform_impl_shared_posix_condition_variable STATIC)
+
+target_sources(platform_impl_shared_posix_condition_variable
+  PRIVATE
+    "posix_condition_variable.cc"
+  PUBLIC
+    "posix_condition_variable.h"
+)
+
+target_include_directories(platform_impl_shared_posix_condition_variable
+  PUBLIC
+    ${CMAKE_CURRENT_SOURCE_DIR}
+)
+
+target_link_libraries(platform_impl_shared_posix_condition_variable
+  PUBLIC
+    platform_api
+    platform_impl_shared_posix_lock
+    platform_types
+    absl::raw_logging_internal
+)
+
+add_library(platform_impl_shared_file STATIC)
+
+target_sources(platform_impl_shared_file
+  PRIVATE
+    "file_impl.cc"
+  PUBLIC
+    "file_impl.h"
+)
+
+target_include_directories(platform_impl_shared_file
+  PUBLIC
+    ${CMAKE_CURRENT_SOURCE_DIR}
+)
+
+target_link_libraries(platform_impl_shared_file
+  PUBLIC
+    platform_api
+    platform_types
+)
+
+add_library(platform_impl_shared_atomic_boolean STATIC)
+
+target_sources(platform_impl_shared_atomic_boolean
+  PUBLIC
+    "atomic_boolean_impl.h"
+)
+
+target_include_directories(platform_impl_shared_atomic_boolean
+  PUBLIC
+    ${CMAKE_CURRENT_SOURCE_DIR}
+)
+
+target_link_libraries(platform_impl_shared_atomic_boolean
+  PUBLIC
+    platform_api
+    platform_types
+)
+
+set_target_properties(platform_impl_shared_atomic_boolean
+  PROPERTIES
+    LINKER_LANGUAGE CXX
+)
+
+add_subdirectory(sample)

cpp/platform/impl/shared/atomic_boolean_impl.h

@@ -0,0 +1,47 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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 PLATFORM_IMPL_SHARED_ATOMIC_BOOLEAN_IMPL_H_
+#define PLATFORM_IMPL_SHARED_ATOMIC_BOOLEAN_IMPL_H_
+
+#include <atomic>
+
+#include "platform/api/atomic_boolean.h"
+
+namespace location {
+namespace nearby {
+
+class AtomicBooleanImpl : public AtomicBoolean {
+ public:
+  explicit AtomicBooleanImpl(bool initial_value) : value_(initial_value) {}
+  ~AtomicBooleanImpl() override = default;
+
+  // AtomicBoolean:
+  bool get() override {
+    return value_.load();
+  }
+
+  // AtomicBoolean:
+  void set(bool value) override {
+    value_.store(value);
+  }
+
+ private:
+  std::atomic_bool value_;
+};
+
+}  // namespace nearby
+}  // namespace location
+
+#endif  // PLATFORM_IMPL_SHARED_ATOMIC_BOOLEAN_IMPL_H_

cpp/platform/impl/shared/file_impl.cc

@@ -0,0 +1,89 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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 "platform/impl/shared/file_impl.h"
+
+#include <cstddef>
+#include <memory>
+
+namespace location {
+namespace nearby {
+
+// InputFile
+
+InputFileImpl::InputFileImpl(const std::string& path, std::int64_t size)
+    : file_(path), path_(path), total_size_(size) {}
+
+ExceptionOr<ConstPtr<ByteArray>> InputFileImpl::read(int64_t size) {
+  if (!file_.is_open()) {
+    return ExceptionOr<ConstPtr<ByteArray>>(Exception::IO);
+  }
+
+  if (file_.peek() == EOF) {
+    return ExceptionOr<ConstPtr<ByteArray>>(ConstPtr<ByteArray>());
+  }
+
+  if (!file_.good()) {
+    return ExceptionOr<ConstPtr<ByteArray>>(Exception::IO);
+  }
+
+  std::unique_ptr<char[]> read_bytes {new char [size]};
+  file_.read(read_bytes.get(), static_cast<ptrdiff_t>(size));
+  auto num_bytes_read = file_.gcount();
+  if (num_bytes_read == 0) {
+    return ExceptionOr<ConstPtr<ByteArray>>(Exception::IO);
+  }
+
+  return ExceptionOr<ConstPtr<ByteArray>>(
+      MakeConstPtr(new ByteArray(read_bytes.get(), num_bytes_read)));
+}
+
+std::string InputFileImpl::getFilePath() const { return path_; }
+
+std::int64_t InputFileImpl::getTotalSize() const { return total_size_; }
+
+void InputFileImpl::close() {
+  if (file_.is_open()) {
+    file_.close();
+  }
+}
+
+// OutputFile
+
+OutputFileImpl::OutputFileImpl(const std::string& path) : file_(path) {}
+
+Exception::Value OutputFileImpl::write(ConstPtr<ByteArray> data) {
+  ScopedPtr<ConstPtr<ByteArray>> scoped_data(data);
+
+  if (!file_.is_open()) {
+    return Exception::IO;
+  }
+
+  if (!file_.good()) {
+    return Exception::IO;
+  }
+
+  file_.write(data->getData(), data->size());
+  file_.flush();
+  return file_.good() ? Exception::NONE : Exception::IO;
+}
+
+void OutputFileImpl::close() {
+  if (file_.is_open()) {
+    file_.close();
+  }
+}
+
+}  // namespace nearby
+}  // namespace location

cpp/platform/impl/shared/file_impl.h

@@ -0,0 +1,60 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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 PLATFORM_IMPL_SHARED_FILE_IMPL_H_
+#define PLATFORM_IMPL_SHARED_FILE_IMPL_H_
+
+#include <cstdint>
+#include <fstream>
+
+#include "platform/api/input_file.h"
+#include "platform/api/output_file.h"
+#include "platform/exception.h"
+#include "platform/ptr.h"
+
+namespace location {
+namespace nearby {
+
+class InputFileImpl final : public InputFile {
+ public:
+  InputFileImpl(const std::string& path, std::int64_t size);
+  ~InputFileImpl() override {}
+
+  ExceptionOr<ConstPtr<ByteArray>> read(std::int64_t size) override;
+  std::string getFilePath() const override;
+  std::int64_t getTotalSize() const override;
+  void close() override;
+
+ private:
+  std::ifstream file_;
+  const std::string path_;
+  const std::int64_t total_size_;
+};
+
+class OutputFileImpl final : public OutputFile {
+ public:
+  explicit OutputFileImpl(const std::string& path);
+  ~OutputFileImpl() override {}
+
+  Exception::Value write(ConstPtr<ByteArray> data) override;
+  void close() override;
+
+ private:
+  std::ofstream file_;
+};
+
+}  // namespace nearby
+}  // namespace location
+
+#endif  // PLATFORM_IMPL_SHARED_FILE_IMPL_H_

cpp/platform/impl/shared/file_impl_test.cc

@@ -0,0 +1,147 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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 "platform/impl/shared/file_impl.h"
+
+#include <cstdio>
+#include <cstring>
+#include <fstream>
+#include <memory>
+#include <ostream>
+#include <unistd.h>
+
+#include "gtest/gtest.h"
+
+namespace location {
+namespace nearby {
+
+
+class FileImplTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    path_ = std::tmpnam(nullptr);;
+    std::ofstream output_file(path_);
+    file_ = std::fstream(path_, std::fstream::in | std::fstream::out);
+  }
+
+  void WriteToFile(const std::string& text) {
+    file_ << text;
+    file_.flush();
+    size_ += text.size();
+  }
+
+  size_t GetSize() const { return size_; }
+
+  void AssertEquals(const ExceptionOr<ConstPtr<ByteArray>>& bytes,
+                    const std::string& expected) {
+    ASSERT_TRUE(bytes.ok());
+    ScopedPtr<ConstPtr<ByteArray>> byte_array(bytes.result());
+    ASSERT_STREQ(byte_array->getData(), expected.c_str());
+    ASSERT_EQ(byte_array->size(), expected.length());
+  }
+
+  void AssertNull(const ExceptionOr<ConstPtr<ByteArray>>& bytes) {
+    ASSERT_TRUE(bytes.ok());
+    ASSERT_TRUE(bytes.result().isNull());
+  }
+
+  static constexpr int64_t kMaxSize = 3;
+
+  std::string path_;
+  std::fstream file_;
+  size_t size_ = 0;
+};
+
+TEST_F(FileImplTest, InputFile_NonExistentPath) {
+  InputFileImpl input_file("/not/a/valid/path.txt", GetSize());
+  ExceptionOr<ConstPtr<ByteArray>> read_result = input_file.read(kMaxSize);
+  ASSERT_FALSE(read_result.ok());
+  ASSERT_EQ(read_result.exception(), Exception::IO);
+}
+
+TEST_F(FileImplTest, InputFile_GetFilePath) {
+  InputFileImpl input_file(path_, GetSize());
+  ASSERT_EQ(input_file.getFilePath(), path_);
+}
+
+TEST_F(FileImplTest, InputFile_EmptyFileEOF) {
+  InputFileImpl input_file(path_, GetSize());
+  AssertNull(input_file.read(kMaxSize));
+}
+
+TEST_F(FileImplTest, InputFile_ReadWorks) {
+  WriteToFile("abc");
+  InputFileImpl input_file(path_, GetSize());
+  auto read_data = input_file.read(kMaxSize);
+  read_data.result().destroy();
+  SUCCEED();
+}
+
+TEST_F(FileImplTest, InputFile_ReadUntilEOF) {
+  WriteToFile("abc");
+  InputFileImpl input_file(path_, GetSize());
+  AssertEquals(input_file.read(kMaxSize), "abc");
+  AssertNull(input_file.read(kMaxSize));
+}
+
+TEST_F(FileImplTest, InputFile_ReadWithSize) {
+  WriteToFile("abc");
+  InputFileImpl input_file(path_, GetSize());
+  AssertEquals(input_file.read(2), "ab");
+  AssertEquals(input_file.read(1), "c");
+  AssertNull(input_file.read(kMaxSize));
+}
+
+TEST_F(FileImplTest, InputFile_GetTotalSize) {
+  WriteToFile("abc");
+  InputFileImpl input_file(path_, GetSize());
+  EXPECT_EQ(input_file.getTotalSize(), 3);
+  AssertEquals(input_file.read(1), "a");
+  EXPECT_EQ(input_file.getTotalSize(), 3);
+}
+
+TEST_F(FileImplTest, InputFile_Close) {
+  WriteToFile("abc");
+  InputFileImpl input_file(path_, GetSize());
+  input_file.close();
+  ExceptionOr<ConstPtr<ByteArray>> read_result = input_file.read(kMaxSize);
+  ASSERT_FALSE(read_result.ok());
+  ASSERT_EQ(read_result.exception(), Exception::IO);
+}
+
+TEST_F(FileImplTest, OutputFile_NonExistentPath) {
+  OutputFileImpl output_file("/not/a/valid/path.txt");
+  ConstPtr<ByteArray> bytes = MakeConstPtr(new ByteArray("a", 1));
+  Exception::Value write_result = output_file.write(bytes);
+  ASSERT_EQ(write_result, Exception::IO);
+}
+
+TEST_F(FileImplTest, OutputFile_Write) {
+  OutputFileImpl output_file(path_);
+  ConstPtr<ByteArray> bytes1 = MakeConstPtr(new ByteArray("a", 1));
+  ConstPtr<ByteArray> bytes2 = MakeConstPtr(new ByteArray("bc", 2));
+  ASSERT_EQ(output_file.write(bytes1), Exception::NONE);
+  ASSERT_EQ(output_file.write(bytes2), Exception::NONE);
+  InputFileImpl input_file(path_, GetSize());
+  AssertEquals(input_file.read(kMaxSize), "abc");
+}
+
+TEST_F(FileImplTest, OutputFile_Close) {
+  OutputFileImpl output_file(path_);
+  output_file.close();
+  ConstPtr<ByteArray> bytes = MakeConstPtr(new ByteArray("a", 1));
+  ASSERT_EQ(output_file.write(bytes), Exception::IO);
+}
+}  // namespace nearby
+}  // namespace location

cpp/platform/impl/shared/posix_condition_variable.cc

@@ -0,0 +1,42 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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 "platform/impl/shared/posix_condition_variable.h"
+
+namespace location {
+namespace nearby {
+
+PosixConditionVariable::PosixConditionVariable(Ptr<PosixLock> lock)
+    : lock_(lock), attr_(), cond_() {
+  pthread_condattr_init(&attr_);
+
+  pthread_cond_init(&cond_, &attr_);
+}
+
+PosixConditionVariable::~PosixConditionVariable() {
+  pthread_cond_destroy(&cond_);
+
+  pthread_condattr_destroy(&attr_);
+}
+
+void PosixConditionVariable::notify() { pthread_cond_broadcast(&cond_); }
+
+Exception::Value PosixConditionVariable::wait() {
+  pthread_cond_wait(&cond_, &(lock_->mutex_));
+
+  return Exception::kSuccess;
+}
+
+}  // namespace nearby
+}  // namespace location

cpp/platform/impl/shared/posix_condition_variable.h

@@ -0,0 +1,44 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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 PLATFORM_IMPL_SHARED_POSIX_CONDITION_VARIABLE_H_
+#define PLATFORM_IMPL_SHARED_POSIX_CONDITION_VARIABLE_H_
+
+#include <pthread.h>
+
+#include "platform/api/condition_variable.h"
+#include "platform/impl/shared/posix_lock.h"
+#include "platform/ptr.h"
+
+namespace location {
+namespace nearby {
+
+class PosixConditionVariable : public ConditionVariable {
+ public:
+  explicit PosixConditionVariable(Ptr<PosixLock> lock);
+  ~PosixConditionVariable() override;
+
+  void notify() override;
+  Exception::Value wait() override;
+
+ private:
+  Ptr<PosixLock> lock_;
+  pthread_condattr_t attr_;
+  pthread_cond_t cond_;
+};
+
+}  // namespace nearby
+}  // namespace location
+
+#endif  // PLATFORM_IMPL_SHARED_POSIX_CONDITION_VARIABLE_H_

cpp/platform/impl/shared/posix_lock.cc

@@ -0,0 +1,38 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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 "platform/impl/shared/posix_lock.h"
+
+namespace location {
+namespace nearby {
+
+PosixLock::PosixLock() : attr_(), mutex_() {
+  pthread_mutexattr_init(&attr_);
+  pthread_mutexattr_settype(&attr_, PTHREAD_MUTEX_RECURSIVE);
+
+  pthread_mutex_init(&mutex_, &attr_);
+}
+
+PosixLock::~PosixLock() {
+  pthread_mutex_destroy(&mutex_);
+
+  pthread_mutexattr_destroy(&attr_);
+}
+
+void PosixLock::lock() { pthread_mutex_lock(&mutex_); }
+
+void PosixLock::unlock() { pthread_mutex_unlock(&mutex_); }
+
+}  // namespace nearby
+}  // namespace location

cpp/platform/impl/shared/posix_lock.h

@@ -0,0 +1,43 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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 PLATFORM_IMPL_SHARED_POSIX_LOCK_H_
+#define PLATFORM_IMPL_SHARED_POSIX_LOCK_H_
+
+#include <pthread.h>
+
+#include "platform/api/lock.h"
+
+namespace location {
+namespace nearby {
+
+class PosixLock : public Lock {
+ public:
+  PosixLock();
+  ~PosixLock() override;
+
+  void lock() override;
+  void unlock() override;
+
+ private:
+  friend class PosixConditionVariable;
+
+  pthread_mutexattr_t attr_;
+  pthread_mutex_t mutex_;
+};
+
+}  // namespace nearby
+}  // namespace location
+
+#endif  // PLATFORM_IMPL_SHARED_POSIX_LOCK_H_

cpp/platform/impl/shared/sample/BUILD

@@ -0,0 +1,36 @@
+# Copyright 2020 Google LLC
+#
+# 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
+#
+#     https://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.
+
+cc_library(
+    name = "sample_wifi_medium",
+    srcs = [
+        "sample_wifi_medium.cc",
+    ],
+    hdrs = [
+        "sample_wifi_medium.h",
+    ],
+    visibility = [
+        "//googlemac/iPhone/Shared/Nearby/Connections:__subpackages__",
+        "//core:__subpackages__",
+        "//platform/impl:__subpackages__",
+        "//location/nearby/setup/core:__subpackages__",
+    ],
+    deps = [
+        "//platform:types",
+        "//platform:utils",
+        "//platform/api",
+        "//platform/port:string",
+        "//absl/time",
+    ],
+)

cpp/platform/impl/shared/sample/CMakeLists.txt

@@ -0,0 +1,31 @@
+# Copyright 2020 Google LLC
+#
+# 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
+#
+#     https://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.
+
+add_library(platform_impl_shared_sample STATIC)
+
+target_sources(platform_impl_shared_sample
+  PRIVATE
+    sample_wifi_medium.cc
+  PUBLIC
+    sample_wifi_medium.h
+)
+
+target_link_libraries(platform_impl_shared_sample
+  PUBLIC
+    absl::time
+    platform_api
+    platform_port_string
+    platform_types
+    platform_utils
+)

cpp/platform/impl/shared/sample/sample_wifi_medium.cc

@@ -0,0 +1,124 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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 "platform/impl/shared/sample/sample_wifi_medium.h"
+
+#include <cstdint>
+
+#include "platform/prng.h"
+#include "absl/time/clock.h"
+#include "absl/time/time.h"
+
+namespace location {
+namespace nearby {
+namespace sample {
+
+namespace {
+
+const char* kOpenSSID = "__OPEN__";
+const char* kWpaPskSSID = "__WPA_PSK__";
+const char* kWepSSID = "__WEP__";
+const char* kNoInternetConnectivitySSID = "__NO_INTERNET_CONNECTIVITY__";
+const char* kConnectionFailureSSID = "__CONNECTION_FAILURE__";
+const char* kAuthFailureSSID = "__AUTH_FAILURE__";
+
+std::uint32_t boundedUInt32(std::uint32_t upper_limit) {
+  return Prng().nextUInt32() % (upper_limit + 1);
+}
+
+void randomSleep(std::uint32_t upper_limit_millis) {
+  absl::SleepFor(absl::Milliseconds(boundedUInt32(upper_limit_millis)));
+}
+
+}  // namespace
+
+std::vector<SampleWifiScanResult> SampleWifiMedium::canned_scan_results_;
+
+SampleWifiMedium::SampleWifiMedium() : current_ssid_() {
+  // One-time initialization of our static canned_scan_results_.
+  if (canned_scan_results_.empty()) {
+    canned_scan_results_.push_back(
+        SampleWifiScanResult(kOpenSSID, 1, 2401, WifiAuthType::OPEN));
+    canned_scan_results_.push_back(
+        SampleWifiScanResult(kWpaPskSSID, 2, 5002, WifiAuthType::WPA_PSK));
+    canned_scan_results_.push_back(
+        SampleWifiScanResult(kWepSSID, 3, 2403, WifiAuthType::WEP));
+    canned_scan_results_.push_back(SampleWifiScanResult(
+        kNoInternetConnectivitySSID, 4, 5004, WifiAuthType::OPEN));
+    canned_scan_results_.push_back(SampleWifiScanResult(
+        kConnectionFailureSSID, 5, 2405, WifiAuthType::OPEN));
+    canned_scan_results_.push_back(
+        SampleWifiScanResult(kAuthFailureSSID, 6, 5006, WifiAuthType::OPEN));
+  }
+}
+
+SampleWifiMedium::~SampleWifiMedium() {}
+
+bool SampleWifiMedium::scan(
+    Ptr<WifiMedium::ScanResultCallback> scan_result_callback) {
+  // Sleep for up to 10 seconds, to simulate performing an actual Wifi scan.
+  randomSleep(10 * 1000);
+
+  // Construct the response.
+  std::vector<ConstPtr<WifiScanResult> > scan_results;
+  for (std::vector<SampleWifiScanResult>::const_iterator it =
+           canned_scan_results_.begin();
+       it != canned_scan_results_.end(); it++) {
+    scan_results.push_back(ConstPtr<WifiScanResult>(
+        new SampleWifiScanResult(it->getSSID(), it->getSignalStrengthDbm(),
+                                 it->getFrequencyMhz(), it->getAuthType())));
+  }
+
+  // And report it back.
+  scan_result_callback->onScanResults(scan_results);
+
+  return false;
+}
+
+WifiConnectionStatus::Value SampleWifiMedium::connectToNetwork(
+    const std::string& ssid, const std::string& password,
+    WifiAuthType::Value auth_type) {
+  // Sleep for up to 10 seconds, to simulate actually connecting to the SSID.
+  randomSleep(10 * 1000);
+
+  if (kConnectionFailureSSID == ssid) {
+    return WifiConnectionStatus::CONNECTION_FAILURE;
+  }
+
+  if (kAuthFailureSSID == ssid) {
+    return WifiConnectionStatus::AUTH_FAILURE;
+  }
+
+  return WifiConnectionStatus::CONNECTED;
+}
+
+bool SampleWifiMedium::verifyInternetConnectivity() {
+  if (current_ssid_.empty()) {
+    return false;
+  }
+
+  // Sleep for up to 5 seconds, to simulate actually verifying internet
+  // connectivity.
+  randomSleep(5 * 1000);
+
+  return current_ssid_ != kNoInternetConnectivitySSID;
+}
+
+std::string SampleWifiMedium::getIPAddress() {
+  return current_ssid_.empty() ? "" : "1.2.3.4";
+}
+
+}  // namespace sample
+}  // namespace nearby
+}  // namespace location

cpp/platform/impl/shared/sample/sample_wifi_medium.h

@@ -0,0 +1,73 @@
+// Copyright 2020 Google LLC
+//
+// 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
+//
+//     https://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 PLATFORM_IMPL_SHARED_SAMPLE_SAMPLE_WIFI_MEDIUM_H_
+#define PLATFORM_IMPL_SHARED_SAMPLE_SAMPLE_WIFI_MEDIUM_H_
+
+#include "platform/api/wifi.h"
+
+namespace location {
+namespace nearby {
+namespace sample {
+
+class SampleWifiScanResult : public WifiScanResult {
+ public:
+  SampleWifiScanResult(const std::string& ssid,
+                       std::int32_t signal_strength_dbm,
+                       std::int32_t frequency_mhz,
+                       WifiAuthType::Value auth_type)
+      : ssid_(ssid),
+        signal_strength_dbm_(signal_strength_dbm),
+        frequency_mhz_(frequency_mhz),
+        auth_type_(auth_type) {}
+  ~SampleWifiScanResult() override {}
+
+  std::string getSSID() const override { return ssid_; }
+  std::int32_t getSignalStrengthDbm() const override {
+    return signal_strength_dbm_;
+  }
+  std::int32_t getFrequencyMhz() const override { return frequency_mhz_; }
+  WifiAuthType::Value getAuthType() const override { return auth_type_; }
+
+ private:
+  const std::string ssid_;
+  const std::int32_t signal_strength_dbm_;
+  const std::int32_t frequency_mhz_;
+  const WifiAuthType::Value auth_type_;
+};
+
+class SampleWifiMedium : public WifiMedium {
+ public:
+  SampleWifiMedium();
+  ~SampleWifiMedium() override;
+
+  bool scan(Ptr<ScanResultCallback> scan_result_callback) override;
+  WifiConnectionStatus::Value connectToNetwork(
+      const std::string& ssid, const std::string& password,
+      WifiAuthType::Value auth_type) override;
+  bool verifyInternetConnectivity() override;
+  std::string getIPAddress() override;
+
+ private:
+  static std::vector<SampleWifiScanResult> canned_scan_results_;
+
+  // The SSID this Wifi stack is currently connected to; empty string if none.
+  std::string current_ssid_;
+};
+
+}  // namespace sample
+}  // namespace nearby
+}  // namespace location
+
+#endif  // PLATFORM_IMPL_SHARED_SAMPLE_SAMPLE_WIFI_MEDIUM_H_