interface/wx/process.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        process.h
   3 // Purpose:     interface of wxProcess
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     Signal constants used by wxProcess.
  11 */
  12 enum wxSignal
  13 {
  14     wxSIGNONE = 0,  //!< verify if the process exists under Unix
  15     wxSIGHUP,
  16     wxSIGINT,
  17     wxSIGQUIT,
  18     wxSIGILL,
  19     wxSIGTRAP,
  20     wxSIGABRT,
  21     wxSIGEMT,
  22     wxSIGFPE,
  23     wxSIGKILL,      //!< forcefully kill, dangerous!
  24     wxSIGBUS,
  25     wxSIGSEGV,
  26     wxSIGSYS,
  27     wxSIGPIPE,
  28     wxSIGALRM,
  29     wxSIGTERM       //!< terminate the process gently
  30 };
  31
  32 /**
  33     Return values for wxProcess::Kill.
  34 */
  35 enum wxKillError
  36 {
  37     wxKILL_OK,              //!< no error
  38     wxKILL_BAD_SIGNAL,      //!< no such signal
  39     wxKILL_ACCESS_DENIED,   //!< permission denied
  40     wxKILL_NO_PROCESS,      //!< no such process
  41     wxKILL_ERROR            //!< another, unspecified error
  42 };
  43
  44
  45 /**
  46     @class wxProcess
  47
  48     The objects of this class are used in conjunction with the ::wxExecute() function.
  49     When a wxProcess object is passed to ::wxExecute(), its OnTerminate() virtual method
  50     is called when the process terminates. This allows the program to be (asynchronously)
  51     notified about the process termination and also retrieve its exit status which is
  52     unavailable from ::wxExecute() in the case of asynchronous execution.
  53
  54     @note If the process termination notification is processed by the
  55     parent, it is responsible for deleting the wxProcess object which sent it.
  56     However, if it is not processed, the object will delete itself and so the
  57     library users should only delete those objects whose notifications have been
  58     processed (and call wxProcess::Detach for others).
  59
  60     wxProcess also supports IO redirection of the child process. For this, you have
  61     to call its Redirect() method before passing it to ::wxExecute().
  62     If the child process was launched successfully, GetInputStream(), GetOutputStream()
  63     and GetErrorStream() can then be used to retrieve the streams corresponding to the
  64     child process standard output, input and error output respectively.
  65
  66     @beginEventEmissionTable{wxProcessEvent}
  67     @event{EVT_END_PROCESS(id, func)}
  68         Process a @c wxEVT_END_PROCESS event, sent by wxProcess::OnTerminate upon
  69         the external process termination.
  70     @endEventTable
  71
  72     @library{wxbase}
  73     @category{appmanagement}
  74
  75     @see wxExecute(), @ref page_samples_exec
  76 */
  77 class wxProcess : public wxEvtHandler
  78 {
  79 public:
  80     /**
  81         Constructs a process object. @a id is only used in the case you want to
  82         use wxWidgets events. It identifies this object, or another window that will
  83         receive the event.
  84
  85         If the @a parent parameter is different from @NULL, it will receive
  86         a @c wxEVT_END_PROCESS notification event (you should insert @c EVT_END_PROCESS
  87         macro in the event table of the parent to handle it) with the given @a id.
  88
  89         @param parent
  90             The event handler parent.
  91         @param id
  92             id of an event.
  93     */
  94     wxProcess(wxEvtHandler* parent = NULL, int id = -1);
  95
  96     /**
  97         Creates an object without any associated parent (and hence no id neither)
  98         but allows to specify the @a flags which can have the value of
  99         @c wxPROCESS_DEFAULT or @c wxPROCESS_REDIRECT.
 100
 101         Specifying the former value has no particular effect while using the latter
 102         one is equivalent to calling Redirect().
 103     */
 104     wxProcess(int flags);
 105
 106     /**
 107         Destroys the wxProcess object.
 108     */
 109     virtual ~wxProcess();
 110
 111     /**
 112         Closes the output stream (the one connected to the stdin of the child
 113         process).
 114
 115         This function can be used to indicate to the child process that
 116         there is no more data to be read - usually, a filter program will only
 117         terminate when the input stream is closed.
 118     */
 119     void CloseOutput();
 120
 121     /**
 122         Normally, a wxProcess object is deleted by its parent when it receives the
 123         notification about the process termination. However, it might happen that the
 124         parent object is destroyed before the external process is terminated (e.g. a
 125         window from which this external process was launched is closed by the user)
 126         and in this case it @b should not delete the wxProcess object, but
 127         @b should call Detach() instead. After the wxProcess object is detached
 128         from its parent, no notification events will be sent to the parent and the
 129         object will delete itself upon reception of the process termination
 130         notification.
 131     */
 132     void Detach();
 133
 134     /**
 135         Returns @true if the given process exists in the system.
 136
 137         @see Kill(), @ref page_samples_exec "Exec sample"
 138     */
 139     static bool Exists(int pid);
 140
 141     /**
 142         Returns an input stream which corresponds to the standard error output (stderr)
 143         of the child process.
 144     */
 145     wxInputStream* GetErrorStream() const;
 146
 147     /**
 148         It returns an input stream corresponding to the standard output stream of the
 149         subprocess. If it is @NULL, you have not turned on the redirection.
 150
 151         @see Redirect().
 152     */
 153     wxInputStream* GetInputStream() const;
 154
 155     /**
 156         It returns an output stream correspoding to the input stream of the subprocess.
 157         If it is @NULL, you have not turned on the redirection.
 158
 159         @see Redirect().
 160     */
 161     wxOutputStream* GetOutputStream() const;
 162
 163     /**
 164         Returns the process ID of the process launched by Open().
 165     */
 166     long GetPid() const;
 167
 168     /**
 169         Returns @true if there is data to be read on the child process standard
 170         error stream.
 171
 172         @see IsInputAvailable()
 173     */
 174     bool IsErrorAvailable() const;
 175
 176     /**
 177         Returns @true if there is data to be read on the child process standard
 178         output stream.
 179
 180         This allows to write simple (and extremely inefficient) polling-based code
 181         waiting for a better mechanism in future wxWidgets versions.
 182         See the @ref page_samples_exec "exec sample" for an example of using this
 183         function.
 184
 185         @see IsInputOpened()
 186     */
 187     bool IsInputAvailable() const;
 188
 189     /**
 190         Returns @true if the child process standard output stream is opened.
 191     */
 192     bool IsInputOpened() const;
 193
 194     /**
 195         Send the specified signal to the given process. Possible signal values
 196         can be one of the ::wxSignal enumeration values.
 197
 198         @c wxSIGNONE, @c wxSIGKILL and @c wxSIGTERM have the same meaning
 199         under both Unix and Windows but all the other signals are equivalent to
 200         @c wxSIGTERM under Windows.
 201
 202         The @a flags parameter can be @c wxKILL_NOCHILDREN (the default),
 203         or @c wxKILL_CHILDREN, in which case the child processes of this
 204         process will be killed too. Note that under Unix, for @c wxKILL_CHILDREN
 205         to work you should have created the process passing @c wxEXEC_MAKE_GROUP_LEADER.
 206
 207         Returns the element of ::wxKillError enum.
 208
 209         @see Exists(), wxKill(), @ref page_samples_exec "Exec sample"
 210     */
 211     static wxKillError Kill(int pid, wxSignal sig = wxSIGTERM,
 212                             int flags = wxKILL_NOCHILDREN);
 213
 214     /**
 215         It is called when the process with the pid @a pid finishes.
 216         It raises a wxWidgets event when it isn't overridden.
 217
 218         @param pid
 219             The pid of the process which has just terminated.
 220         @param status
 221             The exit code of the process.
 222     */
 223     virtual void OnTerminate(int pid, int status);
 224
 225     /**
 226         This static method replaces the standard @c popen() function: it launches
 227         the process specified by the @a cmd parameter and returns the wxProcess
 228         object which can be used to retrieve the streams connected to the standard
 229         input, output and error output of the child process.
 230
 231         If the process couldn't be launched, @NULL is returned.
 232
 233         @remarks
 234         In any case the returned pointer should @b not be deleted, rather the process
 235         object will be destroyed automatically when the child process terminates. This
 236         does mean that the child process should be told to quit before the main program
 237         exits to avoid memory leaks.
 238
 239         @param cmd
 240             The command to execute, including optional arguments.
 241         @param flags
 242             The flags to pass to ::wxExecute().
 243             Note: @c wxEXEC_SYNC should not be used.
 244
 245         @return A pointer to new wxProcess object or @NULL on error.
 246
 247         @see ::wxExecute()
 248     */
 249     static wxProcess* Open(const wxString& cmd,
 250                            int flags = wxEXEC_ASYNC);
 251
 252     /**
 253         Turns on redirection.
 254
 255         ::wxExecute() will try to open a couple of pipes to catch the subprocess stdio.
 256         The caught input stream is returned by GetOutputStream() as a non-seekable stream.
 257         The caught output stream is returned by GetInputStream() as a non-seekable stream.
 258     */
 259     void Redirect();
 260 };
 261
 262
 263
 264 /**
 265     @class wxProcessEvent
 266
 267     A process event is sent to the wxEvtHandler specified to wxProcess
 268     when a process is terminated.
 269
 270     @beginEventTable{wxProcessEvent}
 271     @event{EVT_END_PROCESS(id, func)}
 272         Process a @c wxEVT_END_PROCESS event. @a id is the identifier of the process
 273         object (the id passed to the wxProcess constructor) or a window to receive
 274         the event.
 275     @endEventTable
 276
 277     @library{wxbase}
 278     @category{events}
 279
 280     @see wxProcess, @ref overview_events
 281 */
 282 class wxProcessEvent : public wxEvent
 283 {
 284 public:
 285     /**
 286         Constructor.
 287
 288         Takes a wxProcessObject or window id, a process id and an exit status.
 289     */
 290     wxProcessEvent(int id = 0, int pid = 0, int exitcode = 0);
 291
 292     /**
 293         Returns the exist status.
 294     */
 295     int GetExitCode();
 296
 297     /**
 298         Returns the process id.
 299     */
 300     int GetPid();
 301 };
 302