Add installer::SetupSingleton.

chrome/installer/setup/setup_singleton_unittest.cc

Index: chrome/installer/setup/setup_singleton_unittest.cc
diff --git a/chrome/installer/setup/setup_singleton_unittest.cc b/chrome/installer/setup/setup_singleton_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..e9e89b703aa6608293fd4c270f0986e1f3a87c9d
--- /dev/null
+++ b/chrome/installer/setup/setup_singleton_unittest.cc
@@ -0,0 +1,218 @@
+// Copyright 2016 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 "chrome/installer/setup/setup_singleton.h"
+
+#include <Windows.h>
+
+#include <string>
+#include <vector>
+
+#include "base/command_line.h"
+#include "base/files/file.h"
+#include "base/files/file_path.h"
+#include "base/files/scoped_temp_dir.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/test/multiprocess_test.h"
+#include "base/test/test_timeouts.h"
+#include "base/threading/platform_thread.h"
+#include "base/time/time.h"
+#include "chrome/installer/util/installation_state.h"
+#include "chrome/installer/util/installer_state.h"
+#include "chrome/installer/util/master_preferences.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/multiprocess_func_list.h"
+
+namespace installer {
+
+namespace {
+
+constexpr char kInstallDirSwitch[] = "install-dir";
+constexpr base::char16 kSentinelFileName[] = L"sentinel.txt";
+constexpr base::char16 kTestProcessReadyEventName[] =
+    L"Local\\ChromeSetupSingletonTestProcessReady";
+
+enum ErrorCode {
+  SUCCESS,
+  SETUP_SINGLETON_ACQUISITION_FAILED,
+  SENTINEL_FILE_CREATE_ERROR,
+  WAIT_RETURNED_FALSE,
+};
+
+base::CommandLine GetDummyCommandLine() {
+  return base::CommandLine(base::FilePath(FILE_PATH_LITERAL("dummy.exe")));
+}
+
+base::string16 HashFilePath(const base::FilePath& path) {
+  return base::SizeTToString16(
+      std::hash<base::FilePath::StringType>()(path.value()));
+}
+
+ErrorCode CreateAndDeleteSentinelFile(const base::FilePath& install_dir) {
+  const base::FilePath sentinel_file_path =
+      install_dir.Append(kSentinelFileName);
+
+  base::File file(sentinel_file_path, base::File::FLAG_CREATE |
+                                          base::File::FLAG_WRITE |
+                                          base::File::FLAG_DELETE_ON_CLOSE);
+  if (!file.IsValid())
+    return SENTINEL_FILE_CREATE_ERROR;
+
+  base::PlatformThread::Sleep(TestTimeouts::tiny_timeout());
+  return SUCCESS;
+}
+
+MULTIPROCESS_TEST_MAIN(SetupSingletonTestExclusiveAccessProcessMain) {
+  base::CommandLine* const command_line =
+      base::CommandLine::ForCurrentProcess();
+  const base::FilePath install_dir =
+      command_line->GetSwitchValuePath(kInstallDirSwitch);
+
+  InstallationState original_state;
+  InstallerState installer_state;
+  installer_state.set_target_path_for_testing(install_dir);
+
+  // Acquire the exclusive right to modify the Chrome installation.
+  std::unique_ptr<SetupSingleton> setup_singleton(SetupSingleton::Acquire(
+      GetDummyCommandLine(), MasterPreferences::ForCurrentProcess(),
+      &installer_state, &original_state));
+  if (!setup_singleton)
+    return SETUP_SINGLETON_ACQUISITION_FAILED;
+
+  // Create a sentinel file and delete it after a few milliseconds. This will
+  // fail if the sentinel file already exists (which shouldn't be the case since
+  // we are in the scope of a SetupSingleton).
+  return CreateAndDeleteSentinelFile(install_dir);
+}
+
+MULTIPROCESS_TEST_MAIN(SetupSingletonTestWaitOtherSetupSingletonProcessMain) {
+  base::CommandLine* const command_line =
+      base::CommandLine::ForCurrentProcess();
+  const base::FilePath install_dir =
+      command_line->GetSwitchValuePath(kInstallDirSwitch);
+
+  InstallationState original_state;
+  InstallerState installer_state;
+  installer_state.set_target_path_for_testing(install_dir);
+
+  // Acquire the exclusive right to modify the Chrome installation.
+  std::unique_ptr<SetupSingleton> setup_singleton(SetupSingleton::Acquire(
+      GetDummyCommandLine(), MasterPreferences::ForCurrentProcess(),
+      &installer_state, &original_state));
+  if (!setup_singleton)
+    return SETUP_SINGLETON_ACQUISITION_FAILED;
+
+  // Signal an event to indicate that this process has acquired the
+  // SetupSingleton.
+  base::WaitableEvent ready_event(base::win::ScopedHandle(::CreateEvent(
+      nullptr, FALSE, FALSE,
+      (kTestProcessReadyEventName + HashFilePath(install_dir)).c_str())));
+  ready_event.Signal();
+
+  // Wait indefinitely. This should only return when another SetupSingleton is
+  // instantiated for |install_dir|.
+  if (!setup_singleton->Wait(base::TimeDelta::Max()))
+    return WAIT_RETURNED_FALSE;
+
+  // Create a sentinel file and delete it after a few milliseconds. This will
+  // fail if the sentinel file already exists (which shouldn't be the case since
+  // we are in the scope of a SetupSingleton).
+  return CreateAndDeleteSentinelFile(install_dir);
+}
+
+class SetupSingletonTest : public base::MultiProcessTest {
+ public:
+  SetupSingletonTest() = default;
+
+  void SetUp() override { ASSERT_TRUE(install_dir_.CreateUniqueTempDir()); }
+
+  base::CommandLine MakeCmdLine(const std::string& procname) override {
+    base::CommandLine command_line =
+        base::MultiProcessTest::MakeCmdLine(procname);
+    command_line.AppendSwitchPath(kInstallDirSwitch, install_dir_path());
+    return command_line;
+  }
+
+  base::Process SpawnChildProcess(const std::string& process_name) {
+    base::LaunchOptions options;
+    options.start_hidden = true;
+    return SpawnChildWithOptions(process_name, options);
+  }
+
+  const base::FilePath& install_dir_path() const { return install_dir_.path(); }
+
+ private:
+  base::ScopedTempDir install_dir_;
+
+  DISALLOW_COPY_AND_ASSIGN(SetupSingletonTest);
+};
+
+}  // namespace
+
+// Verify that a single SetupSingleton can be active at a time for a given
+// Chrome installation.
+TEST_F(SetupSingletonTest, ExclusiveAccess) {
+  constexpr int kNumProcesses = 10;
+
+  std::vector<base::Process> processes;
+  for (int i = 0; i < kNumProcesses; ++i) {
+    processes.push_back(
+        SpawnChildProcess("SetupSingletonTestExclusiveAccessProcessMain"));
+  }
+
+  for (base::Process& process : processes) {
+    int exit_code = 0;
+    EXPECT_TRUE(process.WaitForExit(&exit_code));
+    EXPECT_EQ(SUCCESS, exit_code);
+  }
+}
+
+// Verify that Wait() returns false when its delay expires.
+TEST_F(SetupSingletonTest, WaitNoOtherSetupSingleton) {
+  InstallationState original_state;
+  InstallerState installer_state;
+  installer_state.set_target_path_for_testing(install_dir_path());
+  std::unique_ptr<SetupSingleton> setup_singleton(SetupSingleton::Acquire(
+      GetDummyCommandLine(), MasterPreferences::ForCurrentProcess(),
+      &installer_state, &original_state));
+  ASSERT_TRUE(setup_singleton);
+
+  EXPECT_FALSE(setup_singleton->Wait(TestTimeouts::tiny_timeout()));
+}
+
+// Verify that Wait() returns true immediately when another SetupSingleton is
+// instantiated.
+TEST_F(SetupSingletonTest, WaitOtherSetupSingleton) {
+  base::Process wait_process =
+      SpawnChildProcess("SetupSingletonTestWaitOtherSetupSingletonProcessMain");
+
+  // Wait until the other process acquires the SetupSingleton.
+  base::WaitableEvent ready_event(base::win::ScopedHandle(::CreateEvent(
+      nullptr, FALSE, FALSE,
+      (kTestProcessReadyEventName + HashFilePath(install_dir_path()))
+          .c_str())));
+  ready_event.Wait();
+
+  // Acquire the SetupSingleton.
+  InstallationState original_state;
+  InstallerState installer_state;
+  installer_state.set_target_path_for_testing(install_dir_path());
+  std::unique_ptr<SetupSingleton> setup_singleton(SetupSingleton::Acquire(
+      GetDummyCommandLine(), MasterPreferences::ForCurrentProcess(),
+      &installer_state, &original_state));
+  ASSERT_TRUE(setup_singleton);
+
+  // Create a sentinel file and delete it after a few milliseconds. This will
+  // fail if the sentinel file already exists (which shouldn't be the case since
+  // we are in the scope of a SetupSingleton).
+  EXPECT_EQ(SUCCESS, CreateAndDeleteSentinelFile(install_dir_path()));
+
+  // Join |wait_process|.
+  int exit_code = 0;
+  EXPECT_TRUE(wait_process.WaitForExit(&exit_code));
+  EXPECT_EQ(SUCCESS, exit_code);
+}
+
+}  // namespace installer