added wxEXEC_BLOCK flag (patch 1620430)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@45325 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -79,6 +79,7 @@ All:
 - Added wxMutex::LockTimeout() (Aleksandr Napylov)
 - Added wxMemoryInputStream(wxInputStream&) ctor (Stas Sergeev)
 - Implemented wxMemoryInputStream::CanRead()
+- Added wxEXEC_BLOCK flag (Hank Schultz)
 
 All (GUI):
 

docs/latex/wx/function.tex

@@ -647,6 +647,13 @@ needed). Calling \helpref{wxKill}{wxkill} passing wxKILL\_CHILDREN will
 kill this process as well as all of its children (except those which have
 started their own session).
 
+The {\tt wxEXEC\_NOEVENTS} flag prevents processing of any events from taking
+place while the child process is running. It should be only used for very
+short-lived processes as otherwise the application windows risk becoming
+unresponsive from the users point of view. As this flag only makes sense with
+{\tt wxEXEC\_SYNC}, {\tt wxEXEC\_BLOCK} equal to the sum of both of these flags
+is provided as a convenience.
+
 Finally, you may use the third overloaded version of this function to execute
 a process (always synchronously, the contents of \arg{flags} is or'd with
 \texttt{wxEXEC\_SYNC}) and capture its output in the array \arg{output}. The

include/wx/utils.h

@@ -320,7 +320,15 @@ enum
     // by default synchronous execution disables all program windows to avoid
     // that the user interacts with the program while the child process is
     // running, you can use this flag to prevent this from happening
-    wxEXEC_NODISABLE = 8
+    wxEXEC_NODISABLE = 8,
+
+    // by default, the event loop is run while waiting for synchronous execution
+    // to complete and this flag can be used to simply block the main process
+    // until the child process finishes
+    wxEXEC_NOEVENTS = 16,
+
+    // convenient synonym for flags given system()-like behaviour
+    wxEXEC_BLOCK = wxEXEC_SYNC | wxEXEC_NOEVENTS
 };
 
 // Execute another program.

src/unix/utilsunx.cpp

@@ -38,6 +38,7 @@
 #include "wx/unix/private.h"
 
 #include <pwd.h>
+#include <sys/wait.h>       // waitpid()
 
 #ifdef HAVE_SYS_SELECT_H
 #   include <sys/select.h>
@@ -1237,6 +1238,8 @@ int wxGUIAppTraits::WaitForChild(wxExecuteData& execData)
     }
 
 
+    if ( !(flags & wxEXEC_NOEVENTS) )
+    {
 #if defined(__DARWIN__) && (defined(__WXMAC__) || defined(__WXCOCOA__))
         endProcData->tag = wxAddProcessCallbackForPid(endProcData, execData.pid);
 #else
@@ -1248,13 +1251,48 @@ int wxGUIAppTraits::WaitForChild(wxExecuteData& execData)
 
         execData.pipeEndProcDetect.Close();
 #endif // defined(__DARWIN__) && (defined(__WXMAC__) || defined(__WXCOCOA__))
+    }
 
     if ( flags & wxEXEC_SYNC )
     {
         wxBusyCursor bc;
-        wxWindowDisabler *wd = flags & wxEXEC_NODISABLE ? NULL
+        int exitcode = 0;
+
+        wxWindowDisabler *wd = flags & (wxEXEC_NODISABLE | wxEXEC_NOEVENTS)
+                                    ? NULL
                                     : new wxWindowDisabler;
 
+        if ( flags & wxEXEC_NOEVENTS )
+        {
+            // just block waiting for the child to exit
+            int status = 0;
+
+            int result = waitpid(execData.pid, &status, 0);
+
+            if ( result == -1 )
+            {
+                wxLogLastError(_T("waitpid"));
+                exitcode = -1;
+            }
+            else
+            {
+                wxASSERT_MSG( result == execData.pid,
+                              _T("unexpected waitpid() return value") );
+
+                if ( WIFEXITED(status) )
+                {
+                    exitcode = WEXITSTATUS(status);
+                }
+                else // abnormal termination?
+                {
+                    wxASSERT_MSG( WIFSIGNALED(status),
+                                  _T("unexpected child wait status") );
+                    exitcode = -1;
+                }
+            }
+        }
+        else // !wxEXEC_NOEVENTS
+        {
             // endProcData->pid will be set to 0 from GTK_EndProcessDetector when the
             // process terminates
             while ( endProcData->pid != 0 )
@@ -1285,7 +1323,8 @@ int wxGUIAppTraits::WaitForChild(wxExecuteData& execData)
                 wxYield();
             }
 
-        int exitcode = endProcData->exitcode;
+            exitcode = endProcData->exitcode;
+        }
 
         delete wd;
         delete endProcData;