wxWidgets/interface/process.h
2008-03-20 13:45:17 +00:00

250 lines
8.8 KiB
Objective-C

/////////////////////////////////////////////////////////////////////////////
// Name: process.h
// Purpose: interface of wxProcess
// Author: wxWidgets team
// RCS-ID: $Id$
// Licence: wxWindows license
/////////////////////////////////////////////////////////////////////////////
/**
@class wxProcess
@wxheader{process.h}
The objects of this class are used in conjunction with the
wxExecute() function. When a wxProcess object is passed to
wxExecute(), its wxProcess::OnTerminate virtual method
is called when the process terminates. This allows the program to be
(asynchronously) notified about the process termination and also retrieve its
exit status which is unavailable from wxExecute() in the case of
asynchronous execution.
Please note that if the process termination notification is processed by the
parent, it is responsible for deleting the wxProcess object which sent it.
However, if it is not processed, the object will delete itself and so the
library users should only delete those objects whose notifications have been
processed (and call wxProcess::Detach for others).
wxProcess also supports IO redirection of the child process. For this, you have
to call its wxProcess::Redirect method before passing it to
wxExecute(). If the child process was launched successfully,
wxProcess::GetInputStream,
wxProcess::GetOutputStream and
wxProcess::GetErrorStream can then be used to retrieve
the streams corresponding to the child process standard output, input and
error output respectively.
@b wxPerl note: In wxPerl this class has an additional @c Destroy method,
for explicit destruction.
@library{wxbase}
@category{appmanagement}
@see wxExecute(), @ref overview_sampleexec "exec sample"
*/
class wxProcess : public wxEvtHandler
{
public:
//@{
/**
Constructs a process object. @a id is only used in the case you want to
use wxWidgets events. It identifies this object, or another window that will
receive the event.
If the @a parent parameter is different from @NULL, it will receive
a wxEVT_END_PROCESS notification event (you should insert EVT_END_PROCESS
macro in the event table of the parent to handle it) with the given @e id.
The second constructor creates an object without any associated parent (and
hence no id neither) but allows to specify the @a flags which can have the
value of @c wxPROCESS_DEFAULT or @c wxPROCESS_REDIRECT. Specifying the
former value has no particular effect while using the latter one is equivalent
to calling Redirect().
@param parent
The event handler parent.
@param id
id of an event.
@param flags
either wxPROCESS_DEFAULT or wxPROCESS_REDIRECT
*/
wxProcess(wxEvtHandler* parent = NULL, int id = -1);
wxProcess(int flags);
//@}
/**
Destroys the wxProcess object.
*/
~wxProcess();
/**
Closes the output stream (the one connected to the stdin of the child
process). This function can be used to indicate to the child process that
there is no more data to be read - usually, a filter program will only
terminate when the input stream is closed.
*/
void CloseOutput();
/**
Normally, a wxProcess object is deleted by its parent when it receives the
notification about the process termination. However, it might happen that the
parent object is destroyed before the external process is terminated (e.g. a
window from which this external process was launched is closed by the user)
and in this case it @b should not delete the wxProcess object, but
@b should call Detach() instead. After the wxProcess object is detached
from its parent, no notification events will be sent to the parent and the
object will delete itself upon reception of the process termination
notification.
*/
void Detach();
/**
Returns @true if the given process exists in the system.
@see Kill(), @ref overview_sampleexec "Exec sample"
*/
static bool Exists(int pid);
/**
Returns an input stream which corresponds to the standard error output (stderr)
of the child process.
*/
wxInputStream* GetErrorStream() const;
/**
It returns an input stream corresponding to the standard output stream of the
subprocess. If it is @NULL, you have not turned on the redirection.
See Redirect().
*/
wxInputStream* GetInputStream() const;
/**
It returns an output stream correspoding to the input stream of the subprocess.
If it is @NULL, you have not turned on the redirection.
See Redirect().
*/
wxOutputStream* GetOutputStream() const;
/**
Returns the process ID of the process launched by Open().
*/
long GetPid() const;
/**
Returns @true if there is data to be read on the child process standard
error stream.
@see IsInputAvailable()
*/
bool IsErrorAvailable() const;
/**
Returns @true if there is data to be read on the child process standard
output stream. This allows to write simple (and extremely inefficient)
polling-based code waiting for a better mechanism in future wxWidgets versions.
See the @ref overview_sampleexec "exec sample" for an example of using this
function.
@see IsInputOpened()
*/
bool IsInputAvailable() const;
/**
Returns @true if the child process standard output stream is opened.
*/
bool IsInputOpened() const;
/**
Send the specified signal to the given process. Possible signal values are:
@c wxSIGNONE, @c wxSIGKILL and @c wxSIGTERM have the same meaning
under both Unix and Windows but all the other signals are equivalent to
@c wxSIGTERM under Windows.
The @a flags parameter can be wxKILL_NOCHILDREN (the default),
or wxKILL_CHILDREN, in which case the child processes of this
process will be killed too. Note that under Unix, for wxKILL_CHILDREN
to work you should have created the process passing wxEXEC_MAKE_GROUP_LEADER.
Returns the element of @c wxKillError enum:
@see Exists(), wxKill(), @ref overview_sampleexec "Exec sample"
*/
static wxKillError Kill(int pid, wxSignal signal = wxSIGNONE,
int flags = wxKILL_NOCHILDREN);
/**
It is called when the process with the pid
@param pid finishes.
It raises a wxWidgets event when it isn't overridden.
pid
The pid of the process which has just terminated.
@param status
The exit code of the process.
*/
void OnTerminate(int pid, int status);
/**
This static method replaces the standard @c popen() function: it launches
the process specified by the @a cmd parameter and returns the wxProcess
object which can be used to retrieve the streams connected to the standard
input, output and error output of the child process.
If the process couldn't be launched, @NULL is returned. Note that in any
case the returned pointer should @b not be deleted, rather the process
object will be destroyed automatically when the child process terminates. This
does mean that the child process should be told to quit before the main program
exits to avoid memory leaks.
@param cmd
The command to execute, including optional arguments.
@param flags
The flags to pass to wxExecute.
NOTE: wxEXEC_SYNC should not be used.
@returns A pointer to new wxProcess object or @NULL on error.
@see wxExecute()
*/
static wxProcess* Open(const wxString& cmd,
int flags = wxEXEC_ASYNC);
/**
Turns on redirection. wxExecute will try to open a couple of pipes
to catch the subprocess stdio. The caught input stream is returned by
GetOutputStream() as a non-seekable stream. The caught output stream is returned
by GetInputStream() as a non-seekable stream.
*/
void Redirect();
};
/**
@class wxProcessEvent
@wxheader{process.h}
A process event is sent when a process is terminated.
@library{wxbase}
@category{events}
@see wxProcess, @ref overview_eventhandlingoverview
*/
class wxProcessEvent : public wxEvent
{
public:
/**
Constructor. Takes a wxProcessObject or window id, a process id and an
exit status.
*/
wxProcessEvent(int id = 0, int pid = 0, int exitcode = 0);
/**
Returns the exist status.
*/
int GetExitCode();
/**
Returns the process id.
*/
int GetPid() const;
};