Rewrite wxExecute() implementation under Unix.

This commit changes wxExecute() to handle SIGCHLD to be notified about the
child process termination instead of detecting when the file descriptor
corresponding to the other end of a pipe opened in the parent process was
closed in the child as this was not reliable and could (and did) result in not
detecting the termination of the child processes that closed all their file
descriptors before exiting.

This commit also removes a lot of platform-specific code duplicating the
generic event loop sources support and reuses it for wxExecute() purposes too.

Final big change is that wxEndProcessData was merged into wxExecuteData and we
don't have two similar but quite different classes any more but just one,
which is used both to pass the information from wxExecute() to wxAppTraits
methods and to store this information until the child termination.

Closes #10258.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74350 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/unix/execute.h

@@ -4,63 +4,53 @@
 // Author:      Vadim Zeitlin
 // Id:          $Id$
 // Copyright:   (c) 1998 Robert Roebling, Julian Smart, Vadim Zeitlin
+//              (c) 2013 Vadim Zeitlin
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
 
 #ifndef _WX_UNIX_EXECUTE_H
 #define _WX_UNIX_EXECUTE_H
 
+#include "wx/app.h"
+#include "wx/hashmap.h"
+#include "wx/process.h"
+
 #include "wx/unix/pipe.h"
+#include "wx/private/streamtempinput.h"
 
-class WXDLLIMPEXP_FWD_BASE wxProcess;
-class wxStreamTempInputBuffer;
+class wxEventLoopBase;
 
-struct wxEndProcessData
-{
-    wxEndProcessData()
-    {
-        pid =
-        tag =
-        exitcode = -1;
-        process = NULL;
-        async = false;
-    }
-
-    int pid;                // pid of the process
-    int tag;                // port dependent value
-    wxProcess *process;     // if !NULL: notified on process termination
-    int exitcode;           // the exit code
-    bool async;             // if true, delete us on process termination
-};
-
-// struct in which information is passed from wxExecute() to wxAppTraits
-// methods
-struct wxExecuteData
+// Information associated with a running child process.
+class wxExecuteData
 {
+public:
     wxExecuteData()
     {
         flags =
         pid = 0;
+        exitcode = -1;
 
         process = NULL;
 
-#if wxUSE_STREAMS
-        bufOut =
-        bufErr = NULL;
+        syncEventLoop = NULL;
 
+#if wxUSE_STREAMS
         fdOut =
         fdErr = wxPipe::INVALID_FD;
 #endif // wxUSE_STREAMS
     }
 
-    // get the FD corresponding to the read end of the process end detection
-    // pipe and close the write one
-    int GetEndProcReadFD()
-    {
-        const int fd = pipeEndProcDetect.Detach(wxPipe::Read);
-        pipeEndProcDetect.Close();
-        return fd;
-    }
+    // This must be called in the parent process as soon as fork() returns to
+    // update us with the effective child PID. It also ensures that we handle
+    // SIGCHLD to be able to detect when this PID exits, so wxTheApp must be
+    // available.
+    void OnStart(int pid);
+
+    // Called when the child process exits.
+    void OnExit(int exitcode);
+
+    // Return true if we should (or already did) redirect the child IO.
+    bool IsRedirected() const { return process && process->IsRedirected(); }
 
 
     // wxExecute() flags
@@ -69,26 +59,43 @@ struct wxExecuteData
     // the pid of the child process
     int pid;
 
+    // The exit code of the process, set once the child terminates.
+    int exitcode;
+
     // the associated process object or NULL
     wxProcess *process;
 
-    // pipe used for end process detection
-    wxPipe pipeEndProcDetect;
+    // Local event loop used to wait for the child process termination in
+    // synchronous execution case. We can't create it ourselves as its exact
+    // type depends on the application kind (console/GUI), so we rely on
+    // wxAppTraits setting up this pointer to point to the appropriate object.
+    wxEventLoopBase *syncEventLoop;
 
 #if wxUSE_STREAMS
     // the input buffer bufOut is connected to stdout, this is why it is
     // called bufOut and not bufIn
-    wxStreamTempInputBuffer *bufOut,
-                            *bufErr;
+    wxStreamTempInputBuffer bufOut,
+                            bufErr;
 
     // the corresponding FDs, -1 if not redirected
     int fdOut,
         fdErr;
 #endif // wxUSE_STREAMS
+
+
+private:
+    // SIGCHLD signal handler that checks whether any of the currently running
+    // children have exited.
+    static void OnSomeChildExited(int sig);
+
+    // All currently running child processes indexed by their PID.
+    //
+    // Notice that the container doesn't own its elements.
+    WX_DECLARE_HASH_MAP(int, wxExecuteData*, wxIntegerHash, wxIntegerEqual,
+                        ChildProcessesData);
+    static ChildProcessesData ms_childProcesses;
+
+    wxDECLARE_NO_COPY_CLASS(wxExecuteData);
 };
 
-// this function is called when the process terminates from port specific
-// callback function and is common to all ports (src/unix/utilsunx.cpp)
-extern WXDLLIMPEXP_BASE void wxHandleProcessTermination(wxEndProcessData *proc_data);
-
 #endif // _WX_UNIX_EXECUTE_H