base/process/process.h

   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_PROCESS_PROCESS_H_
   6 #define BASE_PROCESS_PROCESS_PROCESS_H_
   7
   8 #include "base/base_export.h"
   9 #include "base/basictypes.h"
  10 #include "base/move.h"
  11 #include "base/process/process_handle.h"
  12 #include "build/build_config.h"
  13
  14 #if defined(OS_WIN)
  15 #include "base/win/scoped_handle.h"
  16 #endif
  17
  18 namespace base {
  19
  20 // Provides a move-only encapsulation of a process.
  21 //
  22 // This object is not tied to the lifetime of the underlying process: the
  23 // process may be killed and this object may still around, and it will still
  24 // claim to be valid. The actual behavior in that case is OS dependent like so:
  25 //
  26 // Windows: The underlying ProcessHandle will be valid after the process dies
  27 // and can be used to gather some information about that process, but most
  28 // methods will obviously fail.
  29 //
  30 // POSIX: The underlying PorcessHandle is not guaranteed to remain valid after
  31 // the process dies, and it may be reused by the system, which means that it may
  32 // end up pointing to the wrong process.
  33 class BASE_EXPORT Process {
  34   MOVE_ONLY_TYPE_FOR_CPP_03(Process, RValue)
  35
  36  public:
  37   explicit Process(ProcessHandle handle = kNullProcessHandle);
  38
  39   // Move constructor for C++03 move emulation of this type.
  40   Process(RValue other);
  41
  42   // The destructor does not terminate the process.
  43   ~Process() {}
  44
  45   // Move operator= for C++03 move emulation of this type.
  46   Process& operator=(RValue other);
  47
  48   // Returns an object for the current process.
  49   static Process Current();
  50
  51   // Creates an object from a |handle| owned by someone else.
  52   // Don't use this for new code. It is only intended to ease the migration to
  53   // a strict ownership model.
  54   // TODO(rvargas) crbug.com/417532: Remove this code.
  55   static Process DeprecatedGetProcessFromHandle(ProcessHandle handle);
  56
  57   // Returns true if processes can be backgrounded.
  58   static bool CanBackgroundProcesses();
  59
  60   // Returns true if this objects represents a valid process.
  61   bool IsValid() const;
  62
  63   // Returns a handle for this process. There is no guarantee about when that
  64   // handle becomes invalid because this object retains ownership.
  65   ProcessHandle Handle() const;
  66
  67   // Returns a second object that represents this process.
  68   Process Duplicate() const;
  69
  70   // Get the PID for this process.
  71   ProcessId pid() const;
  72
  73   // Returns true if this process is 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.
  81   // NOTE: On POSIX |result_code| is ignored.
  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 of the
  89   // process will be lowered. If value is false, the priority of the process
  90   // will be made "normal" - equivalent to default process priority.
  91   // Returns true if the priority was changed, false otherwise.
  92   bool SetProcessBackgrounded(bool value);
  93
  94   // Returns an integer representing the priority of a process. The meaning
  95   // of this value is OS dependent.
  96   int GetPriority() const;
  97
  98  private:
  99 #if defined(OS_WIN)
 100   bool is_current_process_;
 101   win::ScopedHandle process_;
 102 #else
 103   ProcessHandle process_;
 104 #endif
 105 };
 106
 107 }  // namespace base
 108
 109 #endif  // BASE_PROCESS_PROCESS_PROCESS_H_