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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef CHROME_BROWSER_PROCESS_SINGLETON_H_
6 #define CHROME_BROWSER_PROCESS_SINGLETON_H_
7 #pragma once
8 
9 #include "build/build_config.h"
10 
11 #if defined(OS_WIN)
12 #include <windows.h>
13 #endif  // defined(OS_WIN)
14 
15 #include "base/basictypes.h"
16 #include "base/logging.h"
17 #include "base/memory/ref_counted.h"
18 #include "base/threading/non_thread_safe.h"
19 #include "ui/gfx/native_widget_types.h"
20 
21 #if defined(OS_POSIX)
22 #include "base/file_path.h"
23 #endif  // defined(OS_POSIX)
24 
25 #if defined(USE_X11)
26 #include "base/memory/scoped_temp_dir.h"
27 #endif  // defined(USE_X11)
28 
29 class CommandLine;
30 class FilePath;
31 
32 // ProcessSingleton ----------------------------------------------------------
33 //
34 // This class allows different browser processes to communicate with
35 // each other.  It is named according to the user data directory, so
36 // we can be sure that no more than one copy of the application can be
37 // running at once with a given data directory.
38 //
39 // Implementation notes:
40 // - the Windows implementation uses an invisible global message window;
41 // - the Linux implementation uses a Unix domain socket in the user data dir.
42 
43 class ProcessSingleton : public base::NonThreadSafe {
44  public:
45   enum NotifyResult {
46     PROCESS_NONE,
47     PROCESS_NOTIFIED,
48     PROFILE_IN_USE,
49     LOCK_ERROR,
50   };
51 
52   explicit ProcessSingleton(const FilePath& user_data_dir);
53   ~ProcessSingleton();
54 
55   // Notify another process, if available.
56   // Returns true if another process was found and notified, false if we
57   // should continue with this process.
58   // Windows code roughly based on Mozilla.
59   //
60   // TODO(brettw): this will not handle all cases. If two process start up too
61   // close to each other, the Create() might not yet have happened for the
62   // first one, so this function won't find it.
63   NotifyResult NotifyOtherProcess();
64 
65   // Notify another process, if available.  Otherwise sets ourselves as the
66   // singleton instance.  Returns PROCESS_NONE if we became the singleton
67   // instance.
68   NotifyResult NotifyOtherProcessOrCreate();
69 
70 #if defined(OS_LINUX)
71   // Exposed for testing.  We use a timeout on Linux, and in tests we want
72   // this timeout to be short.
73   NotifyResult NotifyOtherProcessWithTimeout(const CommandLine& command_line,
74                                              int timeout_seconds,
75                                              bool kill_unresponsive);
76   NotifyResult NotifyOtherProcessWithTimeoutOrCreate(
77       const CommandLine& command_line,
78       int timeout_seconds);
79 #endif  // defined(OS_LINUX)
80 
81 #if defined(OS_WIN)
82   // Used in specific cases to let us know that there is an existing instance
83   // of Chrome running with this profile. In general, you should not use this
84   // function. Instead consider using NotifyOtherProcessOrCreate().
85   // For non profile-specific method, use
86   // browser_util::IsBrowserAlreadyRunning().
FoundOtherProcessWindow()87   bool FoundOtherProcessWindow() const {
88       return (NULL != remote_window_);
89   }
90 #endif  // defined(OS_WIN)
91 
92   // Sets ourself up as the singleton instance.  Returns true on success.  If
93   // false is returned, we are not the singleton instance and the caller must
94   // exit.
95   bool Create();
96 
97   // Clear any lock state during shutdown.
98   void Cleanup();
99 
100   // Blocks the dispatch of CopyData messages. foreground_window refers
101   // to the window that should be set to the foreground if a CopyData message
102   // is received while the ProcessSingleton is locked.
Lock(gfx::NativeWindow foreground_window)103   void Lock(gfx::NativeWindow foreground_window) {
104     DCHECK(CalledOnValidThread());
105     locked_ = true;
106     foreground_window_ = foreground_window;
107   }
108 
109   // Allows the dispatch of CopyData messages.
Unlock()110   void Unlock() {
111     DCHECK(CalledOnValidThread());
112     locked_ = false;
113     foreground_window_ = NULL;
114   }
115 
locked()116   bool locked() {
117     DCHECK(CalledOnValidThread());
118     return locked_;
119   }
120 
121  private:
122 #if !defined(OS_MACOSX)
123   // Timeout for the current browser process to respond. 20 seconds should be
124   // enough. It's only used in Windows and Linux implementations.
125   static const int kTimeoutInSeconds = 20;
126 #endif
127 
128   bool locked_;
129   gfx::NativeWindow foreground_window_;
130 
131 #if defined(OS_WIN)
132   // This ugly behemoth handles startup commands sent from another process.
133   LRESULT OnCopyData(HWND hwnd, const COPYDATASTRUCT* cds);
134 
135   LRESULT CALLBACK WndProc(HWND hwnd,
136                            UINT message,
137                            WPARAM wparam,
138                            LPARAM lparam);
139 
WndProcStatic(HWND hwnd,UINT message,WPARAM wparam,LPARAM lparam)140   static LRESULT CALLBACK WndProcStatic(HWND hwnd,
141                                         UINT message,
142                                         WPARAM wparam,
143                                         LPARAM lparam) {
144     ProcessSingleton* msg_wnd = reinterpret_cast<ProcessSingleton*>(
145         GetWindowLongPtr(hwnd, GWLP_USERDATA));
146     return msg_wnd->WndProc(hwnd, message, wparam, lparam);
147   }
148 
149   HWND remote_window_;  // The HWND_MESSAGE of another browser.
150   HWND window_;  // The HWND_MESSAGE window.
151 #elif defined(USE_X11)
152   // Path in file system to the socket.
153   FilePath socket_path_;
154 
155   // Path in file system to the lock.
156   FilePath lock_path_;
157 
158   // Path in file system to the cookie file.
159   FilePath cookie_path_;
160 
161   // Temporary directory to hold the socket.
162   ScopedTempDir socket_dir_;
163 
164   // Helper class for linux specific messages.  LinuxWatcher is ref counted
165   // because it posts messages between threads.
166   class LinuxWatcher;
167   scoped_refptr<LinuxWatcher> watcher_;
168 #elif defined(OS_MACOSX)
169   // Path in file system to the lock.
170   FilePath lock_path_;
171 
172   // File descriptor associated with the lockfile, valid between
173   // |Create()| and |Cleanup()|.  Two instances cannot have a lock on
174   // the same file at the same time.
175   int lock_fd_;
176 #endif
177 
178   DISALLOW_COPY_AND_ASSIGN(ProcessSingleton);
179 };
180 
181 #endif  // CHROME_BROWSER_PROCESS_SINGLETON_H_
182