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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 BASE_PROCESS_H_
6 #define BASE_PROCESS_H_
7 #pragma once
8 
9 #include "base/base_api.h"
10 #include "base/basictypes.h"
11 #include "build/build_config.h"
12 
13 #include <sys/types.h>
14 #if defined(OS_WIN)
15 #include <windows.h>
16 #endif
17 
18 namespace base {
19 
20 // ProcessHandle is a platform specific type which represents the underlying OS
21 // handle to a process.
22 // ProcessId is a number which identifies the process in the OS.
23 #if defined(OS_WIN)
24 typedef HANDLE ProcessHandle;
25 typedef DWORD ProcessId;
26 typedef HANDLE UserTokenHandle;
27 const ProcessHandle kNullProcessHandle = NULL;
28 const ProcessId kNullProcessId = 0;
29 #elif defined(OS_POSIX)
30 // On POSIX, our ProcessHandle will just be the PID.
31 typedef pid_t ProcessHandle;
32 typedef pid_t ProcessId;
33 const ProcessHandle kNullProcessHandle = 0;
34 const ProcessId kNullProcessId = 0;
35 #endif  // defined(OS_WIN)
36 
37 #if defined(OS_POSIX) && !defined(OS_MACOSX)
38 // saved_priority_ will be set to this to indicate that it's not holding
39 // a valid value. -20 to 19 are valid process priorities.
40 const int kUnsetProcessPriority = 256;
41 #endif
42 
43 class BASE_API Process {
44  public:
Process()45   Process() : process_(kNullProcessHandle) {
46 #if defined(OS_POSIX) && !defined(OS_MACOSX)
47     saved_priority_ = kUnsetProcessPriority;
48 #endif
49   }
50 
Process(ProcessHandle handle)51   explicit Process(ProcessHandle handle) : process_(handle) {
52 #if defined(OS_POSIX) && !defined(OS_MACOSX)
53     saved_priority_ = kUnsetProcessPriority;
54 #endif
55   }
56 
57   // A handle to the current process.
58   static Process Current();
59 
60   // Get/Set the handle for this process. The handle will be 0 if the process
61   // is no longer running.
handle()62   ProcessHandle handle() const { return process_; }
set_handle(ProcessHandle handle)63   void set_handle(ProcessHandle handle) {
64     process_ = handle;
65 #if defined(OS_POSIX) && !defined(OS_MACOSX)
66     saved_priority_ = kUnsetProcessPriority;
67 #endif
68   }
69 
70   // Get the PID for this process.
71   ProcessId pid() const;
72 
73   // Is the this process the current process.
74   bool is_current() const;
75 
76   // Close the process handle. This will not terminate the process.
77   void Close();
78 
79   // Terminates the process with extreme prejudice. The given result code will
80   // be the exit code of the process. If the process has already exited, this
81   // will do nothing.
82   void Terminate(int result_code);
83 
84   // A process is backgrounded when it's priority is lower than normal.
85   // Return true if this process is backgrounded, false otherwise.
86   bool IsProcessBackgrounded() const;
87 
88   // Set a process as backgrounded. If value is true, the priority
89   // of the process will be lowered. If value is false, the priority
90   // of the process will be made "normal" - equivalent to default
91   // process priority.
92   // Returns true if the priority was changed, false otherwise.
93   bool SetProcessBackgrounded(bool value);
94 
95   // Returns an integer representing the priority of a process. The meaning
96   // of this value is OS dependent.
97   int GetPriority() const;
98 
99  private:
100   ProcessHandle process_;
101 #if defined(OS_POSIX) && !defined(OS_MACOSX)
102   // Holds the priority that the process was set to when it was backgrounded.
103   // If the process wasn't backgrounded it will be kUnsetProcessPriority.
104   int saved_priority_;
105 #endif
106 };
107 
108 }  // namespace base
109 
110 #endif  // BASE_PROCESS_H_
111