/////////////////////////////////////////////////////////////////////////////
// Name:        src/mac/corefoundation/utilsexec_cf.cpp
// Purpose:     Execution-related utilities for Darwin
// Author:      David Elliott, Ryan Norton (wxMacExecute)
// Modified by: Stefan Csomor (added necessary wxT for unicode builds)
// Created:     2004-11-04
// RCS-ID:      $Id: utilsexc_cf.cpp 49240 2007-10-19 04:42:23Z DE $
// Copyright:   (c) David Elliott, Ryan Norton
// Licence:     wxWindows licence
// Notes:       This code comes from src/mac/carbon/utilsexc.cpp,1.11
/////////////////////////////////////////////////////////////////////////////

#include "wx/wxprec.h"
#ifndef WX_PRECOMP
    #include "wx/log.h"
    #include "wx/utils.h"
#endif //ndef WX_PRECOMP
#include "wx/unix/execute.h"
#include "wx/stdpaths.h"
#include "wx/app.h"
#include "wx/apptrait.h"
#include "wx/thread.h"
#include "wx/process.h"

#include <sys/wait.h>

// Use polling instead of Mach ports, which doesn't work on Intel
// due to task_for_pid security issues.

// http://developer.apple.com/technotes/tn/tn2050.html

// What's a better test for Intel vs PPC?
#ifdef WORDS_BIGENDIAN
#define USE_POLLING 0
#else
#define USE_POLLING 1
#endif

#if USE_POLLING

#if wxUSE_THREADS
class wxProcessTerminationEventHandler: public wxEvtHandler
{
  public:
    wxProcessTerminationEventHandler(wxEndProcessData* data)
    {
        m_data = data;
        Connect(-1, wxEVT_END_PROCESS, wxProcessEventHandler(wxProcessTerminationEventHandler::OnTerminate));
    }

    void OnTerminate(wxProcessEvent& event)
    {
        Disconnect(-1, wxEVT_END_PROCESS, wxProcessEventHandler(wxProcessTerminationEventHandler::OnTerminate));
        wxHandleProcessTermination(m_data);

        // NOTE: We don't use this to delay destruction until the next idle run but rather to
        // avoid killing ourselves while our caller (which is our wxEvtHandler superclass
        // ProcessPendingEvents) still needs our m_eventsLocker to be valid.
        // Since we're in the GUI library we can guarantee that ScheduleForDestroy is using
        // the GUI implementation which delays destruction and not the base implementation
        // which does it immediately.
        wxTheApp->GetTraits()->ScheduleForDestroy(this);
    }

    wxEndProcessData* m_data;
};

class wxProcessTerminationThread: public wxThread
{
  public:
    wxProcessTerminationThread(wxEndProcessData* data, wxProcessTerminationEventHandler* handler): wxThread(wxTHREAD_DETACHED)
    {
        m_data = data;
        m_handler = handler;
    }

    virtual void* Entry();

    wxProcessTerminationEventHandler* m_handler;
    wxEndProcessData* m_data;
};

// The problem with this is that we may be examining the
// process e.g. in OnIdle at the point this cleans up the process,
// so we need to delay until it's safe.

void* wxProcessTerminationThread::Entry()
{
    while (true)
    {
        usleep(100);
        int status = 0;
        int rc = waitpid(abs(m_data->pid), & status, 0);
        if (rc != 0)
        {
            if ((rc != -1) && WIFEXITED(status))
                m_data->exitcode = WEXITSTATUS(status);
            else
                m_data->exitcode = -1;

            wxProcessEvent event;
            wxPostEvent(m_handler, event);

            break;
        }
    }

    return NULL;
}

int wxAddProcessCallbackForPid(wxEndProcessData *proc_data, int pid)
{
    if (pid < 1)
        return -1;

    wxProcessTerminationEventHandler* handler = new wxProcessTerminationEventHandler(proc_data);
    wxProcessTerminationThread* thread = new wxProcessTerminationThread(proc_data, handler);

    if (thread->Create() != wxTHREAD_NO_ERROR)
    {
        wxLogDebug(wxT("Could not create termination detection thread."));
        delete thread;
        delete handler;
        return -1;
    }

    thread->Run();

    return 0;
}
#else // !wxUSE_THREADS
int wxAddProcessCallbackForPid(wxEndProcessData*, int)
{
    wxLogDebug(wxT("Could not create termination detection thread."));
    return -1;
}
#endif // wxUSE_THREADS/!wxUSE_THREADS

#else // !USE_POLLING

#include <CoreFoundation/CFMachPort.h>
extern "C" {
#include <mach/mach.h>
}

void wxMAC_MachPortEndProcessDetect(CFMachPortRef port, void *data)
{
    wxEndProcessData *proc_data = (wxEndProcessData*)data;
    wxLogDebug(wxT("Process ended"));
    int status = 0;
    int rc = waitpid(abs(proc_data->pid), &status, WNOHANG);
    if(!rc)
    {
        wxLogDebug(wxT("Mach port was invalidated, but process hasn't terminated!"));
        return;
    }
    if((rc != -1) && WIFEXITED(status))
        proc_data->exitcode = WEXITSTATUS(status);
    else
        proc_data->exitcode = -1;
    wxHandleProcessTermination(proc_data);
}

int wxAddProcessCallbackForPid(wxEndProcessData *proc_data, int pid)
{
    if(pid < 1)
        return -1;
    kern_return_t    kernResult;
    mach_port_t    taskOfOurProcess;
    mach_port_t    machPortForProcess;
    taskOfOurProcess = mach_task_self();
    if(taskOfOurProcess == MACH_PORT_NULL)
    {
        wxLogDebug(wxT("No mach_task_self()"));
        return -1;
    }
    wxLogDebug(wxT("pid=%d"),pid);
    kernResult = task_for_pid(taskOfOurProcess,pid, &machPortForProcess);
    if(kernResult != KERN_SUCCESS)
    {
        wxLogDebug(wxT("no task_for_pid()"));
        // try seeing if it is already dead or something
        // FIXME: a better method would be to call the callback function
        // from idle time until the process terminates. Of course, how
        // likely is it that it will take more than 0.1 seconds for the
        // mach terminate event to make its way to the BSD subsystem?
        usleep(100); // sleep for 0.1 seconds
        wxMAC_MachPortEndProcessDetect(NULL, (void*)proc_data);
        return -1;
    }
    CFMachPortContext termcb_contextinfo;
    termcb_contextinfo.version = 0;
    termcb_contextinfo.info = (void*)proc_data;
    termcb_contextinfo.retain = NULL;
    termcb_contextinfo.release = NULL;
    termcb_contextinfo.copyDescription = NULL;
    CFMachPortRef    CFMachPortForProcess;
    Boolean        ShouldFreePort;
    CFMachPortForProcess = CFMachPortCreateWithPort(NULL, machPortForProcess, NULL, &termcb_contextinfo, &ShouldFreePort);
    if(!CFMachPortForProcess)
    {
        wxLogDebug(wxT("No CFMachPortForProcess"));
        mach_port_deallocate(taskOfOurProcess, machPortForProcess);
        return -1;
    }
    if(ShouldFreePort)
    {
        kernResult = mach_port_deallocate(taskOfOurProcess, machPortForProcess);
        if(kernResult!=KERN_SUCCESS)
        {
            wxLogDebug(wxT("Couldn't deallocate mach port"));
            return -1;
        }
    }
    CFMachPortSetInvalidationCallBack(CFMachPortForProcess, &wxMAC_MachPortEndProcessDetect);
    CFRunLoopSourceRef    runloopsource;
    runloopsource = CFMachPortCreateRunLoopSource(NULL,CFMachPortForProcess, (CFIndex)0);
    if(!runloopsource)
    {
        wxLogDebug(wxT("Couldn't create runloopsource"));
        return -1;
    }

    CFRelease(CFMachPortForProcess);

    CFRunLoopAddSource(CFRunLoopGetCurrent(),runloopsource,kCFRunLoopDefaultMode);
    CFRelease(runloopsource);
    wxLogDebug(wxT("Successfully added notification to the runloop"));
    return 0;
}

#endif // USE_POLLING/!USE_POLLING

/////////////////////////////////////////////////////////////////////////////
// New implementation avoiding mach ports entirely.

#include <CoreFoundation/CFSocket.h>

/*!
    Called due to source signal detected by the CFRunLoop.
    This is nearly identical to the wxGTK equivalent.
 */
extern "C" void WXCF_EndProcessDetector(CFSocketRef s, CFSocketCallBackType callbackType, CFDataRef address, void const *data, void *info)
{
    wxEndProcessData * const proc_data = static_cast<wxEndProcessData*>(info);

/// This code could reasonably be shared between wxMac/wxCocoa and wxGTK ///
    // PID is always positive on UNIX but wx uses the sign bit as a flag.
    int pid = (proc_data->pid > 0) ? proc_data->pid : -proc_data->pid;
    int status = 0;
    int rc = waitpid(pid, &status, WNOHANG);
    if(rc == 0)
    {
        // Keep waiting in case we got a spurious notification
        // NOTE: In my limited testing, this doesn't happen.
        return;
    }

    if(rc == -1)
    {   // Error.. really shouldn't happen but try to gracefully handle it
        wxLogLastError(_T("waitpid"));
        proc_data->exitcode = -1;
    }
    else
    {   // Process ended for some reason
        wxASSERT_MSG(rc == pid, _T("unexpected waitpid() return value"));

        if(WIFEXITED(status))
            proc_data->exitcode = WEXITSTATUS(status);
        else if(WIFSIGNALED(status))
            // wxGTK doesn't do this but why not?
            proc_data->exitcode = -WTERMSIG(status);
        else
        {   // Should NEVER happen according to waitpid docs
            wxLogError(wxT("waitpid indicates process exited but not due to exiting or signalling"));
            proc_data->exitcode = -1;
        }
    }
/// The above code could reasonably be shared between wxMac/wxCocoa and wxGTK ///

    /*
        Either waitpid failed or the process ended successfully.  Either way,
        we're done.  It's not if waitpid is going to magically succeed when
        we get fired again.  CFSocketInvalidate closes the fd for us and also
        invalidates the run loop source for us which should cause it to
        release the CFSocket (thus causing it to be deallocated) and remove
        itself from the runloop which should release it and cause it to also
        be deallocated.  Of course, it's possible the RunLoop hangs onto
        one or both of them by retaining/releasing them within its stack
        frame.  However, that shouldn't be depended on.  Assume that s is
        deallocated due to the following call.
     */
    CFSocketInvalidate(s);

    // Now tell wx that the process has ended.
    wxHandleProcessTermination(proc_data);
}

/*!
    Implements the GUI-specific wxAddProcessCallback for both wxMac and
    wxCocoa using the CFSocket/CFRunLoop API which is available to both.
    Takes advantage of the fact that sockets on UNIX are just regular
    file descriptors and thus even a non-socket file descriptor can
    apparently be used with CFSocket so long as you only tell CFSocket
    to do things with it that would be valid for a non-socket fd.
 */
int wxAddProcessCallback(wxEndProcessData *proc_data, int fd)
{
    static int s_last_tag = 0;
    CFSocketContext context =
    {   0
    ,   static_cast<void*>(proc_data)
    ,   NULL
    ,   NULL
    ,   NULL
    };
    CFSocketRef cfSocket = CFSocketCreateWithNative(kCFAllocatorDefault,fd,kCFSocketReadCallBack,&WXCF_EndProcessDetector,&context);
    if(cfSocket == NULL)
    {
        wxLogError(wxT("Failed to create socket for end process detection"));
        return 0;
    }
    CFRunLoopSourceRef runLoopSource = CFSocketCreateRunLoopSource(kCFAllocatorDefault, cfSocket, /*highest priority:*/0);
    if(runLoopSource == NULL)
    {
        wxLogError(wxT("Failed to create CFRunLoopSource from CFSocket for end process detection"));
        // closes the fd.. we can't really stop it, nor do we necessarily want to.
        CFSocketInvalidate(cfSocket);
        CFRelease(cfSocket);
        return 0;
    }
    // Now that the run loop source has the socket retained and we no longer
    // need to refer to it within this method, we can release it.
    CFRelease(cfSocket);

    CFRunLoopAddSource(CFRunLoopGetCurrent(), runLoopSource, kCFRunLoopCommonModes);
    // Now that the run loop has the source retained we can release it.
    CFRelease(runLoopSource);

    /*
        Feed wx some bullshit.. we don't use it since CFSocket helpfully passes
        itself into our callback and that's enough to be able to
        CFSocketInvalidate it which is all we need to do to get everything we
        just created to be deallocated.
     */
    return ++s_last_tag;
}

/////////////////////////////////////////////////////////////////////////////

// NOTE: This doesn't really belong here but this was a handy file to
// put it in because it's already compiled for wxCocoa and wxMac GUI lib.
#if wxUSE_GUI

static wxStandardPathsCF gs_stdPaths;
wxStandardPathsBase& wxGUIAppTraits::GetStandardPaths()
{
    return gs_stdPaths;
}

#endif // wxUSE_GUI