Mojo Log service and a thread-safe client library.

mojo/services/log/cpp/tests/log_client_unittest.cc

+// Copyright 2015 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 <set>
+#include <thread>
+#include <vector>
+
+#include "mojo/public/cpp/application/application_test_base.h"
+#include "mojo/public/cpp/bindings/strong_binding.h"
+#include "mojo/public/cpp/system/macros.h"
+#include "mojo/public/cpp/utility/run_loop.h"
+#include "mojo/services/log/cpp/log_client.h"
+#include "mojo/services/log/interfaces/entry.mojom.h"
+#include "mojo/services/log/interfaces/log.mojom.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using LogClientTest = mojo::test::ApplicationTestBase;
+using mojo::Environment;
+using mojo::log::LogClient;
+using mojo::log::LogPtr;
+
+namespace mojo {
+namespace {
+
+// A Log implementation that remembers the set of all incoming messages.
+class TestLogServiceImpl : public log::Log {
+ public:
+  explicit TestLogServiceImpl(InterfaceRequest<log::Log> log_req)
+      : binding_(this, std::move(log_req)) {}
+  void AddEntry(mojo::log::EntryPtr entry) override {
+    entry_msgs_.insert(entry->message.To<std::string>());
+  }
+  const std::set<std::string>& entries() { return entry_msgs_; }
+
+ private:
+  mojo::StrongBinding<log::Log> binding_;
+  std::set<std::string> entry_msgs_;
+};
+
+// The number of log entries to issue.
+const int kNumLogEntries = 1000;
+
+// This is our test fallback logger + state.  We simply records whether it's
+// been called.
+bool g_fallback_logger_invoked = false;
+MojoLogger g_fallback_logger = {
+    [](MojoLogLevel log_level,
+       const char* source_file,
+       uint32_t source_line,
+       const char* message) { g_fallback_logger_invoked = true; },
+    nullptr, nullptr};
+
+}  // namespace
+}  // namespace mojo
+
+// This tests that multiple threads can use the MojoLogger that
+// mojo::log::LogClient produces, by spawning off |kNumLogEntries| threads, each
+// issuing one unique log message.
+TEST_F(LogClientTest, ConcurrentAddEntry) {
+  LogPtr log_ptr;
+  std::unique_ptr<mojo::TestLogServiceImpl> log_impl(
+      new mojo::TestLogServiceImpl(mojo::GetProxy(&log_ptr)));
+
+  LogClient lc(std::move(log_ptr), &mojo::g_fallback_logger);
+  Environment::SetDefaultLogger(LogClient::GetLogger());
+
+  // Spawn off numerous threads, each of them issuing a unique log message.
+  std::vector<std::thread> threads;
+  std::set<std::string> expected_entries;
+  for (int i = 0; i < mojo::kNumLogEntries; i++) {
+    std::stringstream msg;
+    msg << "Test message: " << i;
+    EXPECT_TRUE(expected_entries.insert(msg.str()).second);
+
+    std::thread t([](std::string msg) { MOJO_LOG(INFO) << msg; }, msg.str());
+
+    threads.push_back(std::move(t));
+  }
+  for (auto& t : threads) {
+    t.join();
+  }
+
+  // The log message calls should now be processed by TestLogServiceImpl.
+  mojo::RunLoop::current()->RunUntilIdle();
+
+  EXPECT_EQ(expected_entries, log_impl->entries());
+
+  // We kill our binding, closing the connection to the log client and
+  // causing the log client to revert to using its fallback logger.
+  log_impl.reset();
+
+  EXPECT_FALSE(mojo::g_fallback_logger_invoked);
+  MOJO_LOG(INFO) << "Ignore this log message.";
+  EXPECT_TRUE(mojo::g_fallback_logger_invoked);
+}