Added a method WMAvailable(). This will return True if and only if there

is a window manager and we can connect to it, i.e. if it is safe to try
and put up windows.

As a side effect the first call will make the current process frontmost.

diff --git a/Mac/Modules/macosmodule.c b/Mac/Modules/macosmodule.c
index 5b445c0f8538129a03664b19fc6f8a70fd3e7613..80188392231d0c10909f94f2ad0293fc21d6a8e3 100644 (file)
--- a/Mac/Modules/macosmodule.c
+++ b/Mac/Modules/macosmodule.c
@@ -36,6 +36,7 @@ OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include <Events.h>
 #else
 #include <Carbon/Carbon.h>
+#include <ApplicationServices/ApplicationServices.h>
 #endif
 
 static PyObject *MacOS_Error; /* Exception MacOS.Error */
@@ -521,6 +522,47 @@ MacOS_SysBeep(PyObject *self, PyObject *args)
        return Py_None;
 }
 
+static char WMAvailable_doc[] = 
+       "True if this process can interact with the display."
+       "Will foreground the application on the first call as a side-effect."
+       ;
+
+static PyObject *
+MacOS_WMAvailable(PyObject *self, PyObject *args)
+{
+       static PyObject *rv = NULL;
+       
+       if (!PyArg_ParseTuple(args, ""))
+               return NULL;
+       if (!rv) {
+#if TARGET_API_MAC_OSX
+               ProcessSerialNumber psn;
+               
+               /*
+               ** This is a fairly innocuous call to make if we don't have a window
+               ** manager, or if we have no permission to talk to it. It will print
+               ** a message on stderr, but at least it won't abort the process.
+               ** It appears the function caches the result itself, and it's cheap, so
+               ** no need for us to cache.
+               */
+               if (CGMainDisplayID() == 0) {
+                       rv = Py_False;
+               } else {
+                       if (GetCurrentProcess(&psn) < 0 ||
+                               SetFrontProcess(&psn) < 0) {
+                               rv = Py_False;
+                       } else {
+                               rv = Py_True;
+                       }
+               }
+#else
+               rv = Py_True;
+#endif
+       }
+       Py_INCREF(rv);
+       return rv;
+}
+
 static char GetTicks_doc[] = "Return number of ticks since bootup";
 
 static PyObject *
@@ -672,6 +714,7 @@ static PyMethodDef MacOS_Methods[] = {
        {"DebugStr",                    MacOS_DebugStr,         1,      DebugStr_doc},
        {"GetTicks",                    MacOS_GetTicks,         1,      GetTicks_doc},
        {"SysBeep",                     MacOS_SysBeep,          1,      SysBeep_doc},
+       {"WMAvailable",                 MacOS_WMAvailable,              1,      WMAvailable_doc},
 #if !TARGET_API_MAC_OSX
        {"FreeMem",                     MacOS_FreeMem,          1,      FreeMem_doc},
        {"MaxBlock",            MacOS_MaxBlock,         1,      MaxBlock_doc},