utilsexc.cpp

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#endif // wxUSE_STREAMS

// ============================================================================
// wxExecute functions family
// ============================================================================

#if wxUSE_IPC

// connect to the given server via DDE and ask it to execute the command
static bool wxExecuteDDE(const wxString& ddeServer,
                         const wxString& ddeTopic,
                         const wxString& ddeCommand)
{
    bool ok wxDUMMY_INITIALIZE(false);

    wxDDEClient client;
    wxConnectionBase *conn = client.MakeConnection(wxEmptyString,
                                                   ddeServer,
                                                   ddeTopic);
    if ( !conn )
    {
        ok = false;
    }
    else // connected to DDE server
    {
        // the added complication here is that although most programs use
        // XTYP_EXECUTE for their DDE API, some important ones -- like Word
        // and other MS stuff - use XTYP_REQUEST!
        //
        // moreover, anotheri mportant program (IE) understands both but
        // returns an error from Execute() so we must try Request() first
        // to avoid doing it twice
        {
            // we're prepared for this one to fail, so don't show errors
            wxLogNull noErrors;

            ok = conn->Request(ddeCommand) != NULL;
        }

        if ( !ok )
        {
            // now try execute -- but show the errors
            ok = conn->Execute(ddeCommand);
        }
    }

    return ok;
}

#endif // wxUSE_IPC

long wxExecute(const wxString& cmd, int flags, wxProcess *handler)
{
    wxCHECK_MSG( !cmd.empty(), 0, wxT("empty command in wxExecute") );

#if wxUSE_THREADS
    // for many reasons, the code below breaks down if it's called from another
    // thread -- this could be fixed, but as Unix versions don't support this
    // neither I don't want to waste time on this now
    wxASSERT_MSG( wxThread::IsMain(),
                    _T("wxExecute() can be called only from the main thread") );
#endif // wxUSE_THREADS

    wxString command;

#if wxUSE_IPC
    // DDE hack: this is really not pretty, but we need to allow this for
    // transparent handling of DDE servers in wxMimeTypesManager. Usually it
    // returns the command which should be run to view/open/... a file of the
    // given type. Sometimes, however, this command just launches the server
    // and an additional DDE request must be made to really open the file. To
    // keep all this well hidden from the application, we allow a special form
    // of command: WX_DDE#<command>#DDE_SERVER#DDE_TOPIC#DDE_COMMAND in which
    // case we execute just <command> and process the rest below
    wxString ddeServer, ddeTopic, ddeCommand;
    static const size_t lenDdePrefix = 7;   // strlen("WX_DDE:")
    if ( cmd.Left(lenDdePrefix) == _T("WX_DDE#") )
    {
        // speed up the concatenations below
        ddeServer.reserve(256);
        ddeTopic.reserve(256);
        ddeCommand.reserve(256);

        const wxChar *p = cmd.c_str() + 7;
        while ( *p && *p != _T('#') )
        {
            command += *p++;
        }

        if ( *p )
        {
            // skip '#'
            p++;
        }
        else
        {
            wxFAIL_MSG(_T("invalid WX_DDE command in wxExecute"));
        }

        while ( *p && *p != _T('#') )
        {
            ddeServer += *p++;
        }

        if ( *p )
        {
            // skip '#'
            p++;
        }
        else
        {
            wxFAIL_MSG(_T("invalid WX_DDE command in wxExecute"));
        }

        while ( *p && *p != _T('#') )
        {
            ddeTopic += *p++;
        }

        if ( *p )
        {
            // skip '#'
            p++;
        }
        else
        {
            wxFAIL_MSG(_T("invalid WX_DDE command in wxExecute"));
        }

        while ( *p )
        {
            ddeCommand += *p++;
        }

        // if we want to just launch the program and not wait for its
        // termination, try to execute DDE command right now, it can succeed if
        // the process is already running - but as it fails if it's not
        // running, suppress any errors it might generate
        if ( !(flags & wxEXEC_SYNC) )
        {
            wxLogNull noErrors;
            if ( wxExecuteDDE(ddeServer, ddeTopic, ddeCommand) )
            {
                // a dummy PID - this is a hack, of course, but it's well worth
                // it as we don't open a new server each time we're called
                // which would be quite bad
                return -1;
            }
        }
    }
    else
#endif // wxUSE_IPC
    {
        // no DDE
        command = cmd;
    }

    // the IO redirection is only supported with wxUSE_STREAMS
    BOOL redirect = FALSE;

#if wxUSE_STREAMS && !defined(__WXWINCE__)
    wxPipe pipeIn, pipeOut, pipeErr;

    // we'll save here the copy of pipeIn[Write]
    HANDLE hpipeStdinWrite = INVALID_HANDLE_VALUE;

    // open the pipes to which child process IO will be redirected if needed
    if ( handler && handler->IsRedirected() )
    {
        // create pipes for redirecting stdin, stdout and stderr
        if ( !pipeIn.Create() || !pipeOut.Create() || !pipeErr.Create() )
        {
            wxLogSysError(_("Failed to redirect the child process IO"));

            // indicate failure: we need to return different error code
            // depending on the sync flag
            return flags & wxEXEC_SYNC ? -1 : 0;
        }

        redirect = TRUE;
    }
#endif // wxUSE_STREAMS

    // create the process
    STARTUPINFO si;
    wxZeroMemory(si);
    si.cb = sizeof(si);

#if wxUSE_STREAMS && !defined(__WXWINCE__)
    if ( redirect )
    {
        si.dwFlags = STARTF_USESTDHANDLES;

        si.hStdInput = pipeIn[wxPipe::Read];
        si.hStdOutput = pipeOut[wxPipe::Write];
        si.hStdError = pipeErr[wxPipe::Write];

        // when the std IO is redirected, we don't show the (console) process
        // window by default, but this can be overridden by the caller by
        // specifying wxEXEC_NOHIDE flag
        if ( !(flags & wxEXEC_NOHIDE) )
        {
            si.dwFlags |= STARTF_USESHOWWINDOW;
            si.wShowWindow = SW_HIDE;
        }

        // we must duplicate the handle to the write side of stdin pipe to make
        // it non inheritable: indeed, we must close the writing end of pipeIn
        // before launching the child process as otherwise this handle will be
        // inherited by the child which will never close it and so the pipe
        // will never be closed and the child will be left stuck in ReadFile()
        HANDLE pipeInWrite = pipeIn.Detach(wxPipe::Write);
        if ( !::DuplicateHandle
                (
                    ::GetCurrentProcess(),
                    pipeInWrite,
                    ::GetCurrentProcess(),
                    &hpipeStdinWrite,
                    0,                      // desired access: unused here
                    FALSE,                  // not inherited
                    DUPLICATE_SAME_ACCESS   // same access as for src handle
                ) )
        {
            wxLogLastError(_T("DuplicateHandle"));
        }

        ::CloseHandle(pipeInWrite);
    }
#endif // wxUSE_STREAMS

    PROCESS_INFORMATION pi;
    DWORD dwFlags = CREATE_SUSPENDED;

#ifndef __WXWINCE__
    dwFlags |= CREATE_DEFAULT_ERROR_MODE ;
#else
    // we are assuming commands without spaces for now
    wxString moduleName = command.BeforeFirst(wxT(' '));
    wxString arguments = command.AfterFirst(wxT(' '));
#endif

    bool ok = ::CreateProcess
                (
                    // WinCE requires appname to be non null
                    // Win32 allows for null
#ifdef __WXWINCE__
                 (wxChar *)
                 moduleName.c_str(), // application name
                 (wxChar *)
                 arguments.c_str(),  // arguments
#else
                 NULL,               // application name (use only cmd line)
                 (wxChar *)
                 command.c_str(),    // full command line
#endif
                 NULL,               // security attributes: defaults for both
                 NULL,               //   the process and its main thread
                 redirect,           // inherit handles if we use pipes
                 dwFlags,            // process creation flags
                 NULL,               // environment (use the same)
                 NULL,               // current directory (use the same)
                 &si,                // startup info (unused here)
                 &pi                 // process info
                ) != 0;

#if wxUSE_STREAMS && !defined(__WXWINCE__)
    // we can close the pipe ends used by child anyhow
    if ( redirect )
    {
        ::CloseHandle(pipeIn.Detach(wxPipe::Read));
        ::CloseHandle(pipeOut.Detach(wxPipe::Write));
        ::CloseHandle(pipeErr.Detach(wxPipe::Write));
    }
#endif // wxUSE_STREAMS

    if ( !ok )
    {
#if wxUSE_STREAMS && !defined(__WXWINCE__)
        // close the other handles too
        if ( redirect )
        {
            ::CloseHandle(pipeOut.Detach(wxPipe::Read));
            ::CloseHandle(pipeErr.Detach(wxPipe::Read));
        }
#endif // wxUSE_STREAMS

        wxLogSysError(_("Execution of command '%s' failed"), command.c_str());

        return flags & wxEXEC_SYNC ? -1 : 0;
    }

#if wxUSE_STREAMS && !defined(__WXWINCE__)
    // the input buffer bufOut is connected to stdout, this is why it is
    // called bufOut and not bufIn
    wxStreamTempInputBuffer bufOut,
                            bufErr;

    if ( redirect )
    {
        // We can now initialize the wxStreams
        wxPipeInputStream *
            outStream = new wxPipeInputStream(pipeOut.Detach(wxPipe::Read));
        wxPipeInputStream *
            errStream = new wxPipeInputStream(pipeErr.Detach(wxPipe::Read));
        wxPipeOutputStream *
            inStream = new wxPipeOutputStream(hpipeStdinWrite);

        handler->SetPipeStreams(outStream, inStream, errStream);

        bufOut.Init(outStream);
        bufErr.Init(errStream);
    }
#endif // wxUSE_STREAMS

    // create a hidden window to receive notification about process
    // termination
    HWND hwnd = wxCreateHiddenWindow
                (
                    &gs_classForHiddenWindow,
                    wxMSWEXEC_WNDCLASSNAME,
                    (WNDPROC)wxExecuteWindowCbk
                );

    wxASSERT_MSG( hwnd, wxT("can't create a hidden window for wxExecute") );

    // Alloc data
    wxExecuteData *data = new wxExecuteData;
    data->hProcess    = pi.hProcess;
    data->dwProcessId = pi.dwProcessId;
    data->hWnd        = hwnd;
    data->state       = (flags & wxEXEC_SYNC) != 0;
    if ( flags & wxEXEC_SYNC )
    {
        // handler may be !NULL for capturing program output, but we don't use
        // it wxExecuteData struct in this case
        data->handler = NULL;
    }
    else
    {
        // may be NULL or not
        data->handler = handler;
    }

    DWORD tid;
    HANDLE hThread = ::CreateThread(NULL,
                                    0,
                                    wxExecuteThread,
                                    (void *)data,
                                    0,
                                    &tid);

    // resume process we created now - whether the thread creation succeeded or
    // not
    if ( ::ResumeThread(pi.hThread) == (DWORD)-1 )
    {
        // ignore it - what can we do?
        wxLogLastError(wxT("ResumeThread in wxExecute"));
    }

    // close unneeded handle
    if ( !::CloseHandle(pi.hThread) )
        wxLogLastError(wxT("CloseHandle(hThread)"));

    if ( !hThread )
    {
        wxLogLastError(wxT("CreateThread in wxExecute"));

        DestroyWindow(hwnd);
        delete data;

        // the process still started up successfully...
        return pi.dwProcessId;
    }

    ::CloseHandle(hThread);

#if wxUSE_IPC && !defined(__WXWINCE__)
    // second part of DDE hack: now establish the DDE conversation with the
    // just launched process
    if ( !ddeServer.empty() )
    {
        bool ok;

        // give the process the time to init itself
        //
        // we use a very big timeout hoping that WaitForInputIdle() will return
        // much sooner, but not INFINITE just in case the process hangs
        // completely - like this we will regain control sooner or later
        switch ( ::WaitForInputIdle(pi.hProcess, 10000 /* 10 seconds */) )
        {
            default:
                wxFAIL_MSG( _T("unexpected WaitForInputIdle() return code") );
                // fall through

            case -1:
                wxLogLastError(_T("WaitForInputIdle() in wxExecute"));

            case WAIT_TIMEOUT:
                wxLogDebug(_T("Timeout too small in WaitForInputIdle"));

                ok = false;
                break;

            case 0:
                // ok, process ready to accept DDE requests
                ok = wxExecuteDDE(ddeServer, ddeTopic, ddeCommand);
        }

        if ( !ok )
        {
            wxLogDebug(_T("Failed to send DDE request to the process \"%s\"."),
                       cmd.c_str());
        }
    }
#endif // wxUSE_IPC

    if ( !(flags & wxEXEC_SYNC) )
    {
        // clean up will be done when the process terminates

        // return the pid
        return pi.dwProcessId;
    }

    wxAppTraits *traits = wxTheApp ? wxTheApp->GetTraits() : NULL;
    wxCHECK_MSG( traits, -1, _T("no wxAppTraits in wxExecute()?") );

    void *cookie = NULL;
    if ( !(flags & wxEXEC_NODISABLE) )
    {
        // disable all app windows while waiting for the child process to finish
        cookie = traits->BeforeChildWaitLoop();
    }

    // wait until the child process terminates
    while ( data->state )
    {
#if wxUSE_STREAMS && !defined(__WXWINCE__)
        bufOut.Update();
        bufErr.Update();
#endif // wxUSE_STREAMS

        // don't eat 100% of the CPU -- ugly but anything else requires
        // real async IO which we don't have for the moment
        ::Sleep(50);

        // we must process messages or we'd never get wxWM_PROC_TERMINATED
        traits->AlwaysYield();
    }

    if ( !(flags & wxEXEC_NODISABLE) )
    {
        // reenable disabled windows back
        traits->AfterChildWaitLoop(cookie);
    }

    DWORD dwExitCode = data->dwExitCode;
    delete data;

    // return the exit code
    return dwExitCode;
}

long wxExecute(wxChar **argv, int flags, wxProcess *handler)
{
    wxString command;

    for ( ;; )
    {
        command += *argv++;
        if ( !*argv )
            break;

        command += _T(' ');
    }

    return wxExecute(command, flags, handler);
}