base/process.h

   1 // Copyright (c) 2006-2008 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
   8 #include "base/basictypes.h"
   9 #include "build/build_config.h"
  10
  11 #include <sys/types.h>
  12 #if defined(OS_WIN)
  13 #include <windows.h>
  14 #endif
  15
  16 namespace base {
  17
  18 // ProcessHandle is a platform specific type which represents the underlying OS
  19 // handle to a process.
  20 // ProcessId is a number which identifies the process in the OS.
  21 #if defined(OS_WIN)
  22 typedef HANDLE ProcessHandle;
  23 typedef DWORD ProcessId;
  24 typedef HANDLE UserTokenHandle;
  25 const ProcessHandle kNullProcessHandle = NULL;
  26 #elif defined(OS_POSIX)
  27 // On POSIX, our ProcessHandle will just be the PID.
  28 typedef pid_t ProcessHandle;
  29 typedef pid_t ProcessId;
  30 const ProcessHandle kNullProcessHandle = 0;
  31 #endif  // defined(OS_WIN)
  32
  33 #if defined(OS_POSIX) && !defined(OS_MACOSX)
  34 // saved_priority_ will be set to this to indicate that it's not holding
  35 // a valid value. -20 to 19 are valid process priorities.
  36 const int kUnsetProcessPriority = 256;
  37 #endif
  38
  39 class Process {
  40  public:
  41   Process() : process_(kNullProcessHandle) {
  42 #if defined(OS_POSIX) && !defined(OS_MACOSX)
  43     saved_priority_ = kUnsetProcessPriority;
  44 #endif
  45   }
  46
  47   explicit Process(ProcessHandle handle) : process_(handle) {
  48 #if defined(OS_POSIX) && !defined(OS_MACOSX)
  49     saved_priority_ = kUnsetProcessPriority;
  50 #endif
  51   }
  52
  53   // A handle to the current process.
  54   static Process Current();
  55
  56   // Get/Set the handle for this process. The handle will be 0 if the process
  57   // is no longer running.
  58   ProcessHandle handle() const { return process_; }
  59   void set_handle(ProcessHandle handle) {
  60     process_ = handle;
  61 #if defined(OS_POSIX) && !defined(OS_MACOSX)
  62     saved_priority_ = kUnsetProcessPriority;
  63 #endif
  64   }
  65
  66   // Get the PID for this process.
  67   ProcessId pid() const;
  68
  69   // Is the this process the current process.
  70   bool is_current() const;
  71
  72   // Close the process handle. This will not terminate the process.
  73   void Close();
  74
  75   // Terminates the process with extreme prejudice. The given result code will
  76   // be the exit code of the process. If the process has already exited, this
  77   // will do nothing.
  78   void Terminate(int result_code);
  79
  80   // A process is backgrounded when it's priority is lower than normal.
  81   // Return true if this process is backgrounded, false otherwise.
  82   bool IsProcessBackgrounded() const;
  83
  84   // Set a process as backgrounded. If value is true, the priority
  85   // of the process will be lowered. If value is false, the priority
  86   // of the process will be made "normal" - equivalent to default
  87   // process priority.
  88   // Returns true if the priority was changed, false otherwise.
  89   bool SetProcessBackgrounded(bool value);
  90
  91   // Returns an integer representing the priority of a process. The meaning
  92   // of this value is OS dependent.
  93   int GetPriority() const;
  94
  95  private:
  96   ProcessHandle process_;
  97 #if defined(OS_POSIX) && !defined(OS_MACOSX)
  98   // Holds the priority that the process was set to when it was backgrounded.
  99   // If the process wasn't backgrounded it will be kUnsetProcessPriority.
 100   int saved_priority_;
 101 #endif
 102 };
 103
 104 }  // namespace base
 105
 106 #endif  // BASE_PROCESS_H_