Copy some relevant files over from Chromium

atom/browser/process_singleton.h

@@ -0,0 +1,183 @@
+// Copyright (c) 2012 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.
+
+#ifndef CHROME_BROWSER_PROCESS_SINGLETON_H_
+#define CHROME_BROWSER_PROCESS_SINGLETON_H_
+
+#include "build/build_config.h"
+
+#if defined(OS_WIN)
+#include <windows.h>
+#endif  // defined(OS_WIN)
+
+#include <set>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/command_line.h"
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "base/memory/ref_counted.h"
+#include "base/process/process.h"
+#include "base/threading/non_thread_safe.h"
+#include "ui/gfx/native_widget_types.h"
+
+#if defined(OS_POSIX) && !defined(OS_ANDROID)
+#include "base/files/scoped_temp_dir.h"
+#endif
+
+#if defined(OS_WIN)
+#include "base/win/message_window.h"
+#endif  // defined(OS_WIN)
+
+namespace base {
+class CommandLine;
+}
+
+// ProcessSingleton ----------------------------------------------------------
+//
+// This class allows different browser processes to communicate with
+// each other.  It is named according to the user data directory, so
+// we can be sure that no more than one copy of the application can be
+// running at once with a given data directory.
+//
+// Implementation notes:
+// - the Windows implementation uses an invisible global message window;
+// - the Linux implementation uses a Unix domain socket in the user data dir.
+
+class ProcessSingleton : public base::NonThreadSafe {
+ public:
+  enum NotifyResult {
+    PROCESS_NONE,
+    PROCESS_NOTIFIED,
+    PROFILE_IN_USE,
+    LOCK_ERROR,
+  };
+
+  // Implement this callback to handle notifications from other processes. The
+  // callback will receive the command line and directory with which the other
+  // Chrome process was launched. Return true if the command line will be
+  // handled within the current browser instance or false if the remote process
+  // should handle it (i.e., because the current process is shutting down).
+  using NotificationCallback =
+      base::Callback<bool(const base::CommandLine& command_line,
+                          const base::FilePath& current_directory)>;
+
+  ProcessSingleton(const base::FilePath& user_data_dir,
+                   const NotificationCallback& notification_callback);
+  ~ProcessSingleton();
+
+  // Notify another process, if available. Otherwise sets ourselves as the
+  // singleton instance. Returns PROCESS_NONE if we became the singleton
+  // instance. Callers are guaranteed to either have notified an existing
+  // process or have grabbed the singleton (unless the profile is locked by an
+  // unreachable process).
+  // TODO(brettw): Make the implementation of this method non-platform-specific
+  // by making Linux re-use the Windows implementation.
+  NotifyResult NotifyOtherProcessOrCreate();
+
+  // Sets ourself up as the singleton instance.  Returns true on success.  If
+  // false is returned, we are not the singleton instance and the caller must
+  // exit.
+  // NOTE: Most callers should generally prefer NotifyOtherProcessOrCreate() to
+  // this method, only callers for whom failure is preferred to notifying
+  // another process should call this directly.
+  bool Create();
+
+  // Clear any lock state during shutdown.
+  void Cleanup();
+
+#if defined(OS_POSIX) && !defined(OS_ANDROID)
+  static void DisablePromptForTesting();
+#endif
+#if defined(OS_WIN)
+  // Called to query whether to kill a hung browser process that has visible
+  // windows. Return true to allow killing the hung process.
+  using ShouldKillRemoteProcessCallback = base::Callback<bool()>;
+  void OverrideShouldKillRemoteProcessCallbackForTesting(
+      const ShouldKillRemoteProcessCallback& display_dialog_callback);
+#endif
+
+ protected:
+  // Notify another process, if available.
+  // Returns true if another process was found and notified, false if we should
+  // continue with the current process.
+  // On Windows, Create() has to be called before this.
+  NotifyResult NotifyOtherProcess();
+
+#if defined(OS_POSIX) && !defined(OS_ANDROID)
+  // Exposed for testing.  We use a timeout on Linux, and in tests we want
+  // this timeout to be short.
+  NotifyResult NotifyOtherProcessWithTimeout(
+      const base::CommandLine& command_line,
+      int retry_attempts,
+      const base::TimeDelta& timeout,
+      bool kill_unresponsive);
+  NotifyResult NotifyOtherProcessWithTimeoutOrCreate(
+      const base::CommandLine& command_line,
+      int retry_attempts,
+      const base::TimeDelta& timeout);
+  void OverrideCurrentPidForTesting(base::ProcessId pid);
+  void OverrideKillCallbackForTesting(
+      const base::Callback<void(int)>& callback);
+#endif
+
+ private:
+  NotificationCallback notification_callback_;  // Handler for notifications.
+
+#if defined(OS_WIN)
+  bool EscapeVirtualization(const base::FilePath& user_data_dir);
+
+  HWND remote_window_;  // The HWND_MESSAGE of another browser.
+  base::win::MessageWindow window_;  // The message-only window.
+  bool is_virtualized_;  // Stuck inside Microsoft Softricity VM environment.
+  HANDLE lock_file_;
+  base::FilePath user_data_dir_;
+  ShouldKillRemoteProcessCallback should_kill_remote_process_callback_;
+#elif defined(OS_POSIX) && !defined(OS_ANDROID)
+  // Return true if the given pid is one of our child processes.
+  // Assumes that the current pid is the root of all pids of the current
+  // instance.
+  bool IsSameChromeInstance(pid_t pid);
+
+  // Extract the process's pid from a symbol link path and if it is on
+  // the same host, kill the process, unlink the lock file and return true.
+  // If the process is part of the same chrome instance, unlink the lock file
+  // and return true without killing it.
+  // If the process is on a different host, return false.
+  bool KillProcessByLockPath();
+
+  // Default function to kill a process, overridable by tests.
+  void KillProcess(int pid);
+
+  // Allow overriding for tests.
+  base::ProcessId current_pid_;
+
+  // Function to call when the other process is hung and needs to be killed.
+  // Allows overriding for tests.
+  base::Callback<void(int)> kill_callback_;
+
+  // Path in file system to the socket.
+  base::FilePath socket_path_;
+
+  // Path in file system to the lock.
+  base::FilePath lock_path_;
+
+  // Path in file system to the cookie file.
+  base::FilePath cookie_path_;
+
+  // Temporary directory to hold the socket.
+  base::ScopedTempDir socket_dir_;
+
+  // Helper class for linux specific messages.  LinuxWatcher is ref counted
+  // because it posts messages between threads.
+  class LinuxWatcher;
+  scoped_refptr<LinuxWatcher> watcher_;
+#endif
+
+  DISALLOW_COPY_AND_ASSIGN(ProcessSingleton);
+};
+
+#endif  // CHROME_BROWSER_PROCESS_SINGLETON_H_