Add installer::SetupSingleton.

chrome/installer/setup/setup_singleton_unittest.cc

+// 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>

[grt (UTC plus 2), 2016/08/31 12:03:48]

nit: 'w'

[fdoray, 2016/08/31 19:14:21]

Done.

[grt (UTC plus 2), 2016/09/01 12:05:39]

try harder. :-)

+
+#include <string>
+#include <vector>
+
+#include "base/base_switches.h"
+#include "base/command_line.h"
+#include "base/files/file.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/files/scoped_temp_dir.h"
+#include "base/process/launch.h"
+#include "base/strings/string16.h"
+#include "base/threading/platform_thread.h"
+#include "base/time/time.h"
+#include "chrome/installer/util/installer_state.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/multiprocess_func_list.h"
+
+namespace installer {
+
+namespace {
+
+constexpr char kInstallDirSwitch[] = "install-dir";
+constexpr char kSystemLevelSwitch[] = "system-level";
+constexpr base::char16 kSentinelFileName[] = L"sentinel.txt";
+constexpr base::char16 kTestProcessReadyEventName[] =
+    L"Local\\ChromeSetupSingletonTestProcessReady";
+constexpr int kWaitDurationMs = 50;

[grt (UTC plus 2), 2016/08/31 12:03:48]

can you get rid of this and use something in base/test/test_timeouts.h?

[fdoray, 2016/08/31 19:14:22]

Done.

+
+enum ErrorCodes {
+  SUCCESS,
+  SENTINEL_FILE_CREATE_ERROR,
+  SENTINEL_FILE_DELETE_ERROR,
+  WAIT_RETURNED_FALSE,
+};
+
+base::string16 ReplaceBackslashes(const base::string16& path) {
+  base::string16 path_without_backslashes(path);
+  std::replace(path_without_backslashes.begin(), path_without_backslashes.end(),

[grt (UTC plus 2), 2016/08/31 12:03:48]

#include <algorithm>

[fdoray, 2016/08/31 19:14:21]

N/A

+               L'\\', L'/');
+  return path_without_backslashes;
+}
+
+int CreateAndDeleteSentinelFile(const base::FilePath& install_dir) {
+  const base::FilePath sentinel_file_path =
+      install_dir.Append(kSentinelFileName);
+
+  base::File file(sentinel_file_path,

[grt (UTC plus 2), 2016/08/31 12:03:48]

nit: no need to keep this in a local var. you can replace lines 55-59 with:
  if (!base::File(...).IsValid()) {
    return SENTINEL_FILE_CREATE_ERROR;
  }

alternatively, can you open the file with DELETE_ON_CLOSE and just let the File
go out of scope after the wait?

[fdoray, 2016/08/31 19:14:21]

Done.

+                  base::File::FLAG_CREATE | base::File::FLAG_WRITE);
+  if (!file.IsValid())
+    return SENTINEL_FILE_CREATE_ERROR;
+  file.Close();
+
+  base::PlatformThread::Sleep(
+      base::TimeDelta::FromMilliseconds(kWaitDurationMs));
+
+  if (!base::DeleteFile(sentinel_file_path, false))
+    return SENTINEL_FILE_DELETE_ERROR;
+
+  return SUCCESS;
+}
+
+MULTIPROCESS_TEST_MAIN(SetupSingletonTestExclusiveAccessProcessMain) {
+  base::CommandLine* const command_line =
+      base::CommandLine::ForCurrentProcess();
+
+  // Acquire the exclusive right to modify the Chrome installation.
+  const base::FilePath install_dir =
+      command_line->GetSwitchValuePath(kInstallDirSwitch);
+  SetupSingleton setup_singleton(install_dir,
+                                 command_line->HasSwitch(kSystemLevelSwitch));
+
+  // Create a sentinel file and delete it after a few milliseconds. This will
+  // fail it the sentinel file already exists (which shouldn't be the case since

[grt (UTC plus 2), 2016/08/31 12:03:48]

it -> if

[fdoray, 2016/08/31 19:14:21]

Done.

+  // we are in the scope of a SetupSingleton).
+  return CreateAndDeleteSentinelFile(install_dir);
+}
+
+MULTIPROCESS_TEST_MAIN(SetupSingletonTestWaitOtherSetupSingletonProcessMain) {
+  base::CommandLine* const command_line =
+      base::CommandLine::ForCurrentProcess();
+
+  // Acquire the exclusive right to modify the Chrome installation.
+  const base::FilePath install_dir =
+      command_line->GetSwitchValuePath(kInstallDirSwitch);
+  SetupSingleton setup_singleton(install_dir,
+                                 command_line->HasSwitch(kSystemLevelSwitch));
+
+  // Signal an event to indicate that this process has acquired the
+  // SetupSingleton.
+  base::WaitableEvent ready_event(base::win::ScopedHandle(::CreateEvent(
+      nullptr, FALSE, FALSE,
+      (kTestProcessReadyEventName + ReplaceBackslashes(install_dir.value()))
+          .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 it 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 testing::TestWithParam<InstallerState::Level> {
+ public:
+  SetupSingletonTest() = default;
+
+  void SetUp() override { ASSERT_TRUE(install_dir_.CreateUniqueTempDir()); }
+
+  base::Process SpawnChildProcess(const std::string& process_name) {
+    base::CommandLine command_line = *base::CommandLine::ForCurrentProcess();
+    command_line.SetProgram(
+        base::MakeAbsoluteFilePath(command_line.GetProgram()));
+    command_line.AppendSwitchASCII(::switches::kTestChildProcess, process_name);
+    command_line.AppendSwitchPath(kInstallDirSwitch, install_dir_.path());
+    if (GetParam() == InstallerState::SYSTEM_LEVEL)
+      command_line.AppendSwitch(kSystemLevelSwitch);
+    base::LaunchOptions options;
+    options.start_hidden = true;
+    return LaunchProcess(command_line, options);
+  }
+
+  const base::FilePath& install_dir_path() const { return install_dir_.path(); }
+
+ private:
+  base::ScopedTempDir install_dir_;
+
+  DISALLOW_COPY_AND_ASSIGN(SetupSingletonTest);
+};
+
+}  // namespace
+
+INSTANTIATE_TEST_CASE_P(InstallLevel,
+                        SetupSingletonTest,
+                        ::testing::Values(InstallerState::SYSTEM_LEVEL,

[grt (UTC plus 2), 2016/08/31 12:03:48]

i find that the logs (especially failures) are easier to understand if there are
two instantiations, each with one level. for example:

INSTANTIATE_TEST_CASE_P(SystemLevel, SetupSingletonTest,
::testing::Values(InstallerState::SYSTEM_LEVEL));
INSTANTIATE_TEST_CASE_P(UserLevel, SetupSingletonTest,
::testing::Values(InstallerState::USER_LEVEL));

[fdoray, 2016/08/31 19:14:21]

N/A

+                                          InstallerState::USER_LEVEL));
+
+// Verify that a single SetupSingleton can be active at a time for a given
+// Chrome installation.
+TEST_P(SetupSingletonTest, ExclusiveAccess) {
+  constexpr size_t kNumProcesses = 10;

[grt (UTC plus 2), 2016/08/31 12:03:48]

nit: use int for this

[fdoray, 2016/08/31 19:14:21]

Done.

+
+  std::vector<base::Process> processes;
+  for (size_t 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_P(SetupSingletonTest, WaitNoOtherSetupSingleton) {
+  SetupSingleton setup_singleton(install_dir_path(),
+                                 GetParam() == InstallerState::SYSTEM_LEVEL);
+  EXPECT_FALSE(
+      setup_singleton.Wait(base::TimeDelta::FromMilliseconds(kWaitDurationMs)));
+}
+
+// Verify that Wait() returns true immediately when another SetupSingleton is
+// instantiated.
+TEST_P(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 +
+                              ReplaceBackslashes(install_dir_path().value()))
+                                 .c_str())));
+  ready_event.Wait();
+
+  // Acquire the SetupSingleton.
+  SetupSingleton setup_singleton(install_dir_path(),
+                                 GetParam() == InstallerState::SYSTEM_LEVEL);
+
+  // Create a sentinel file and delete it after a few milliseconds. This will
+  // fail it 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