src/solaris/native/sun/awt/awt_mgrsel.c - toolchain/jdk/jdk9_jdk - Git at Google

 /*
  * Copyright (c) 2003, 2004, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */

 #ifdef HEADLESS
     #error This file should not be included in headless library
 #endif

 #include "awt_mgrsel.h"

 static Atom XA_MANAGER = None;

 /*
  * Structures that describes the manager selection AWT listens to with
  * callabacks to the subsytems interested in the selection.  (We only
  * listen to a couple of selections, so linear search is enough).
  */
 struct AwtMgrsel {
     char *selname;              /* base name of selection atoms */
     Atom *per_scr_atoms;        /* per-screen selection atoms (ICCCM 1.2.6) */
     Atom *per_scr_owners;       /* windows currently owning the selection */
     long extra_mask;            /* extra events to listen to on owners */
     void *cookie;
     void (*callback_event)(int, XEvent *, void *); /* extra_mask events */
     void (*callback_owner)(int, Window, long *, void *); /* owner changes */
     struct AwtMgrsel *next;
 };

 static struct AwtMgrsel *mgrsel_list = NULL;


 static int awt_mgrsel_screen(Window w);
 static Window awt_mgrsel_select_per_screen(Atom, long);
 static int awt_mgrsel_managed(XClientMessageEvent *mgrown);
 static int awt_mgrsel_unmanaged(XDestroyWindowEvent *ev);

 #ifdef DEBUG
 static void awt_mgrsel_dtraceManaged(XClientMessageEvent *mgrown);
 #endif


 /*
  * Find which screen the window W is the root of.
  * Returns the screen number, or -1 if W is not a root.
  */
 static int
 awt_mgrsel_screen(Window w)
 {
     Display *dpy = awt_display;
     int scr;

     for (scr = 0; scr < ScreenCount(dpy); ++scr) {
         if (w == RootWindow(dpy, scr)) {
             return (scr);
         }
     }

     return (-1);
 }


 /************************************************************************
  * For every one that asketh receiveth; and he that seeketh findeth;
  * and to him that knocketh it shall be opened.  (Luke 11:10).
  */


 /*
  * A method for a subsytem to express its interest in a certain
  * manager selection.
  *
  * If owner changes, the callback_owner will be called with the screen
  * number and the new owning window when onwership is established, or
  * None if the owner is gone.
  *
  * Events in extra_mask are selected for on owning windows (exsiting
  * ones and on new owners when established) and callback_event will be
  * called with the screen number and an event.
  *
  * The function returns an array of current owners.  The size of the
  * array is ScreenCount(awt_display).  The array is "owned" by this
  * module and should be considered by the caller as read-only.
  */
 const Window *
 awt_mgrsel_select(const char *selname, long extra_mask,
                   void *cookie,
                   void (*callback_event)(int, XEvent *, void *),
                   void (*callback_owner)(int, Window, long *, void *))
 {
     Display *dpy = awt_display;
     struct AwtMgrsel *mgrsel;
     Atom *per_scr_atoms;
     Window *per_scr_owners;
     char *namesbuf;
     char **names;
     int per_scr_sz;
     int nscreens = ScreenCount(dpy);
     int scr;
     Status status;

     DASSERT(selname != NULL);
     DTRACE_PRINTLN1("MG: select: %s", selname);

     /* buffer size for one per-screen atom name */
     per_scr_sz = strlen(selname) + /* "_S" */ 2 + /* %2d */ + 2 /* '\0' */+ 1;

     namesbuf = malloc(per_scr_sz * nscreens);  /* actual storage for names */
     names = malloc(sizeof(char *) * nscreens); /* pointers to names */
     per_scr_atoms = malloc(sizeof(Atom) * nscreens);
     per_scr_owners = malloc(sizeof(Window) * nscreens);
     mgrsel = malloc(sizeof(struct AwtMgrsel));

     if (namesbuf == NULL || names == NULL || per_scr_atoms == NULL
         || per_scr_owners == NULL || mgrsel == NULL)
     {
         DTRACE_PRINTLN("MG: select: unable to allocate memory");
         if (namesbuf != NULL) free(per_scr_atoms);
         if (names != NULL) free(names);
         if (per_scr_atoms != NULL) free(per_scr_atoms);
         if (per_scr_owners != NULL) free(per_scr_owners);
         if (mgrsel != NULL) free(mgrsel);
         return (NULL);
     }


     for (scr = 0; scr < nscreens; ++scr) {
         size_t sz;

         names[scr] = &namesbuf[per_scr_sz * scr];
         sz = snprintf(names[scr], per_scr_sz, "%s_S%-d", selname, scr);
         DASSERT(sz < per_scr_sz);
     }

     status = XInternAtoms(dpy, names, nscreens, False, per_scr_atoms);

     free(names);
     free(namesbuf);

     if (status == 0) {
         DTRACE_PRINTLN("MG: select: XInternAtoms failed");
         free(per_scr_atoms);
         free(per_scr_owners);
         return (NULL);
     }

     mgrsel->selname = strdup(selname);
     mgrsel->per_scr_atoms = per_scr_atoms;
     mgrsel->per_scr_owners = per_scr_owners;
     mgrsel->extra_mask = extra_mask;
     mgrsel->cookie = cookie;
     mgrsel->callback_event = callback_event;
     mgrsel->callback_owner = callback_owner;

     for (scr = 0; scr < nscreens; ++scr) {
         Window owner;

         owner = awt_mgrsel_select_per_screen(per_scr_atoms[scr], extra_mask);
         mgrsel->per_scr_owners[scr] = owner;
 #ifdef DEBUG
         if (owner == None) {
             DTRACE_PRINTLN1("MG:   screen %d - None", scr);
         } else {
             DTRACE_PRINTLN2("MG:   screen %d - 0x%08lx", scr, owner);
         }
 #endif
     }

     mgrsel->next = mgrsel_list;
     mgrsel_list = mgrsel;

     return (per_scr_owners);
 }


 static Window
 awt_mgrsel_select_per_screen(Atom selection, long extra_mask)
 {
     Display *dpy = awt_display;
     Window owner;

     XGrabServer(dpy);

     owner = XGetSelectionOwner(dpy, selection);
     if (owner == None) {
         /* we'll get notified later if one arrives */
         XUngrabServer(dpy);
         /* Workaround for bug 5039226 */
         XSync(dpy, False);
         return (None);
     }

     /*
      * Select for StructureNotifyMask to get DestroyNotify when owner
      * is gone.  Also select for any additional events caller is
      * interested in (e.g. PropertyChangeMask).  Caller will be
      * notifed of these events via ... XXX ...
      */
     XSelectInput(dpy, owner, StructureNotifyMask | extra_mask);

     XUngrabServer(dpy);
     /* Workaround for bug 5039226 */
     XSync(dpy, False);
     return (owner);
 }


 /************************************************************************
  * And so I saw the wicked buried, who had come and gone from the
  * place of the holy, and they were forgotten in the city where they
  * had so done: this is also vanity.  (Eccl 8:10)
  */

 #ifdef DEBUG
 /*
  * Print the message from the new manager that announces it acquired
  * ownership.
  */
 static void
 awt_mgrsel_dtraceManaged(XClientMessageEvent *mgrown)
 {
     Display *dpy = awt_display;
     Atom selection;
     char *selname, *print_selname;
     int scr;

     scr = awt_mgrsel_screen(mgrown->window);

     selection = mgrown->data.l[1];
     print_selname = selname = XGetAtomName(dpy, selection);
     if (selname == NULL) {
         if (selection == None) {
             print_selname = "<None>";
         } else {
             print_selname = "<Unknown>";
         }
     }

     DTRACE_PRINTLN4("MG: new MANAGER for %s: screen %d, owner 0x%08lx (@%lu)",
                    print_selname, scr,
                    mgrown->data.l[2],  /* the window owning the selection */
                    mgrown->data.l[0]); /* timestamp */
     DTRACE_PRINTLN4("MG:   %ld %ld / 0x%lx 0x%lx", /* extra data */
                     mgrown->data.l[3], mgrown->data.l[4],
                     mgrown->data.l[3], mgrown->data.l[4]);

     if (selname != NULL) {
         XFree(selname);
     }
 }
 #endif /* DEBUG */


 static int
 awt_mgrsel_managed(XClientMessageEvent *mgrown)
 {
     Display *dpy = awt_display;
     struct AwtMgrsel *mgrsel;
     int scr;

     long timestamp;
     Atom selection;
     Window owner;
     long *data;

     if (mgrown->message_type != XA_MANAGER) {
         DTRACE_PRINTLN("MG: ClientMessage type != MANAGER, ignoring");
         return (0);
     }

     scr = awt_mgrsel_screen(mgrown->window);

 #ifdef DEBUG
     awt_mgrsel_dtraceManaged(mgrown);
 #endif

     if (scr < 0) {
         DTRACE_PRINTLN("MG: MANAGER ClientMessage with a non-root window!");
         return (0);
     }

     timestamp = mgrown->data.l[0];
     selection = mgrown->data.l[1];
     owner     = mgrown->data.l[2];
     data      = &mgrown->data.l[3]; /* long[2], selection specific */

     /* is this a selection we are intrested in? */
     for (mgrsel = mgrsel_list; mgrsel != NULL; mgrsel = mgrsel->next) {
         if (selection == mgrsel->per_scr_atoms[scr])
             break;
     }

     if (mgrsel == NULL) {
         DTRACE_PRINTLN("MG: not interested in this selection, ignoring");
         return (0);
     }


     mgrsel->per_scr_owners[scr] = owner;

     XSelectInput(dpy, owner, StructureNotifyMask | mgrsel->extra_mask);

     /* notify the listener */
     if (mgrsel->callback_owner != NULL) {
         (*mgrsel->callback_owner)(scr, owner, data, mgrsel->cookie);
     }

     return (1);
 }


 static int
 awt_mgrsel_unmanaged(XDestroyWindowEvent *ev)
 {
     Display *dpy = awt_display;
     struct AwtMgrsel *mgrsel;
     Window exowner;
     int scr;

     exowner = ev->window;       /* selection owner that's gone */

     /* is this a selection we are intrested in? */
     for (mgrsel = mgrsel_list; mgrsel != NULL; mgrsel = mgrsel->next) {
         for (scr = 0; scr < ScreenCount(dpy); ++scr) {
             if (exowner == mgrsel->per_scr_owners[scr]) {
                 /* can one window own selections for more than one screen? */
                 goto out;       /* XXX??? */
             }
         }
     }
   out:
     if (mgrsel == NULL) {
         DTRACE_PRINTLN1("MG: DestroyNotify for 0x%08lx ignored", exowner);
         return (0);
     }

     DTRACE_PRINTLN3("MG: DestroyNotify for 0x%08lx, owner of %s at screen %d",
                     exowner, mgrsel->selname, scr);

     /* notify the listener (pass exowner as data???) */
     if (mgrsel->callback_owner != NULL) {
         (*mgrsel->callback_owner)(scr, None, NULL, mgrsel->cookie);
     }

     return (1);
 }


 /*
  * Hook to be called from toolkit event loop.
  */
 int
 awt_mgrsel_processEvent(XEvent *ev)
 {
     Display *dpy = awt_display;
     struct AwtMgrsel *mgrsel;
     int scr;

     if (ev->type == ClientMessage) { /* new manager announces ownership? */
         if (awt_mgrsel_managed(&ev->xclient))
             return (1);
     }

     if (ev->type == DestroyNotify) { /* manager gives up selection? */
         if (awt_mgrsel_unmanaged(&ev->xdestroywindow))
             return (1);
     }

     /* is this an event selected on one of selection owners? */
     for (mgrsel = mgrsel_list; mgrsel != NULL; mgrsel = mgrsel->next) {
         for (scr = 0; scr < ScreenCount(dpy); ++scr) {
             if (ev->xany.window == mgrsel->per_scr_owners[scr]) {
                 /* can one window own selections for more than one screen? */
                 goto out;       /* XXX??? */
             }
         }
     }
   out:
     DTRACE_PRINT2("MG: screen %d, event %d ...  ",
                   scr, ev->xany.type);
     if (mgrsel == NULL) {
         DTRACE_PRINTLN("ignored");
         return (0);             /* not interested */
     }

     DTRACE_PRINT1("%s ...  ", mgrsel->selname);
     if (mgrsel->callback_event != NULL) {
         DTRACE_PRINTLN("dispatching");
         (*mgrsel->callback_event)(scr, ev, mgrsel->cookie);
     }
 #ifdef DEBUG
     else {
         DTRACE_PRINTLN("no callback");
     }
 #endif

     return (1);
 }


 void
 awt_mgrsel_init(void)
 {
     static Boolean inited = False;

     Display *dpy = awt_display;
     int scr;

     if (inited) {
         return;
     }

     XA_MANAGER = XInternAtom(dpy, "MANAGER", False);
     DASSERT(XA_MANAGER != None);


     /*
      * Listen for ClientMessage's on each screen's root.  We hook into
      * the message loop in the toolkit (with awt_mgrsel_processEvent)
      * to get the events processed.  We need this for notifications of
      * new manager acquiring ownership of the manager selection.
      */
     for (scr = 0; scr < ScreenCount(dpy); ++scr) {
         XSelectInput(dpy, RootWindow(dpy, scr), StructureNotifyMask);
     }

     inited = True;
 }
	/*
	* Copyright (c) 2003, 2004, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	#ifdef HEADLESS
	#error This file should not be included in headless library
	#endif

	#include "awt_mgrsel.h"

	static Atom XA_MANAGER = None;

	/*
	* Structures that describes the manager selection AWT listens to with
	* callabacks to the subsytems interested in the selection. (We only
	* listen to a couple of selections, so linear search is enough).
	*/
	struct AwtMgrsel {
	char selname; / base name of selection atoms */
	Atom per_scr_atoms; / per-screen selection atoms (ICCCM 1.2.6) */
	Atom per_scr_owners; / windows currently owning the selection */
	long extra_mask; /* extra events to listen to on owners */
	void *cookie;
	void (callback_event)(int, XEvent , void ); / extra_mask events */
	void (callback_owner)(int, Window, long , void ); / owner changes */
	struct AwtMgrsel *next;
	};

	static struct AwtMgrsel *mgrsel_list = NULL;


	static int awt_mgrsel_screen(Window w);
	static Window awt_mgrsel_select_per_screen(Atom, long);
	static int awt_mgrsel_managed(XClientMessageEvent *mgrown);
	static int awt_mgrsel_unmanaged(XDestroyWindowEvent *ev);

	#ifdef DEBUG
	static void awt_mgrsel_dtraceManaged(XClientMessageEvent *mgrown);
	#endif



	/*
	* Find which screen the window W is the root of.
	* Returns the screen number, or -1 if W is not a root.
	*/
	static int
	awt_mgrsel_screen(Window w)
	{
	Display *dpy = awt_display;
	int scr;

	for (scr = 0; scr < ScreenCount(dpy); ++scr) {
	if (w == RootWindow(dpy, scr)) {
	return (scr);
	}
	}

	return (-1);
	}


	/************************************************************************
	* For every one that asketh receiveth; and he that seeketh findeth;
	* and to him that knocketh it shall be opened. (Luke 11:10).
	*/


	/*
	* A method for a subsytem to express its interest in a certain
	* manager selection.
	*
	* If owner changes, the callback_owner will be called with the screen
	* number and the new owning window when onwership is established, or
	* None if the owner is gone.
	*
	* Events in extra_mask are selected for on owning windows (exsiting
	* ones and on new owners when established) and callback_event will be
	* called with the screen number and an event.
	*
	* The function returns an array of current owners. The size of the
	* array is ScreenCount(awt_display). The array is "owned" by this
	* module and should be considered by the caller as read-only.
	*/
	const Window *
	awt_mgrsel_select(const char *selname, long extra_mask,
	void *cookie,
	void (callback_event)(int, XEvent , void *),
	void (callback_owner)(int, Window, long , void *))
	{
	Display *dpy = awt_display;
	struct AwtMgrsel *mgrsel;
	Atom *per_scr_atoms;
	Window *per_scr_owners;
	char *namesbuf;
	char **names;
	int per_scr_sz;
	int nscreens = ScreenCount(dpy);
	int scr;
	Status status;

	DASSERT(selname != NULL);
	DTRACE_PRINTLN1("MG: select: %s", selname);

	/* buffer size for one per-screen atom name */
	per_scr_sz = strlen(selname) + /* "_S" / 2 + / %2d / + 2 / '\0' */+ 1;

	namesbuf = malloc(per_scr_sz * nscreens); /* actual storage for names */
	names = malloc(sizeof(char ) nscreens); /* pointers to names */
	per_scr_atoms = malloc(sizeof(Atom) * nscreens);
	per_scr_owners = malloc(sizeof(Window) * nscreens);
	mgrsel = malloc(sizeof(struct AwtMgrsel));

	if (namesbuf == NULL \|\| names == NULL \|\| per_scr_atoms == NULL
	\|\| per_scr_owners == NULL \|\| mgrsel == NULL)
	{
	DTRACE_PRINTLN("MG: select: unable to allocate memory");
	if (namesbuf != NULL) free(per_scr_atoms);
	if (names != NULL) free(names);
	if (per_scr_atoms != NULL) free(per_scr_atoms);
	if (per_scr_owners != NULL) free(per_scr_owners);
	if (mgrsel != NULL) free(mgrsel);
	return (NULL);
	}


	for (scr = 0; scr < nscreens; ++scr) {
	size_t sz;

	names[scr] = &namesbuf[per_scr_sz * scr];
	sz = snprintf(names[scr], per_scr_sz, "%s_S%-d", selname, scr);
	DASSERT(sz < per_scr_sz);
	}

	status = XInternAtoms(dpy, names, nscreens, False, per_scr_atoms);

	free(names);
	free(namesbuf);

	if (status == 0) {
	DTRACE_PRINTLN("MG: select: XInternAtoms failed");
	free(per_scr_atoms);
	free(per_scr_owners);
	return (NULL);
	}

	mgrsel->selname = strdup(selname);
	mgrsel->per_scr_atoms = per_scr_atoms;
	mgrsel->per_scr_owners = per_scr_owners;
	mgrsel->extra_mask = extra_mask;
	mgrsel->cookie = cookie;
	mgrsel->callback_event = callback_event;
	mgrsel->callback_owner = callback_owner;

	for (scr = 0; scr < nscreens; ++scr) {
	Window owner;

	owner = awt_mgrsel_select_per_screen(per_scr_atoms[scr], extra_mask);
	mgrsel->per_scr_owners[scr] = owner;
	#ifdef DEBUG
	if (owner == None) {
	DTRACE_PRINTLN1("MG: screen %d - None", scr);
	} else {
	DTRACE_PRINTLN2("MG: screen %d - 0x%08lx", scr, owner);
	}
	#endif
	}

	mgrsel->next = mgrsel_list;
	mgrsel_list = mgrsel;

	return (per_scr_owners);
	}


	static Window
	awt_mgrsel_select_per_screen(Atom selection, long extra_mask)
	{
	Display *dpy = awt_display;
	Window owner;

	XGrabServer(dpy);

	owner = XGetSelectionOwner(dpy, selection);
	if (owner == None) {
	/* we'll get notified later if one arrives */
	XUngrabServer(dpy);
	/* Workaround for bug 5039226 */
	XSync(dpy, False);
	return (None);
	}

	/*
	* Select for StructureNotifyMask to get DestroyNotify when owner
	* is gone. Also select for any additional events caller is
	* interested in (e.g. PropertyChangeMask). Caller will be
	* notifed of these events via ... XXX ...
	*/
	XSelectInput(dpy, owner, StructureNotifyMask \| extra_mask);

	XUngrabServer(dpy);
	/* Workaround for bug 5039226 */
	XSync(dpy, False);
	return (owner);
	}


	/************************************************************************
	* And so I saw the wicked buried, who had come and gone from the
	* place of the holy, and they were forgotten in the city where they
	* had so done: this is also vanity. (Eccl 8:10)
	*/

	#ifdef DEBUG
	/*
	* Print the message from the new manager that announces it acquired
	* ownership.
	*/
	static void
	awt_mgrsel_dtraceManaged(XClientMessageEvent *mgrown)
	{
	Display *dpy = awt_display;
	Atom selection;
	char selname, print_selname;
	int scr;

	scr = awt_mgrsel_screen(mgrown->window);

	selection = mgrown->data.l[1];
	print_selname = selname = XGetAtomName(dpy, selection);
	if (selname == NULL) {
	if (selection == None) {
	print_selname = "<None>";
	} else {
	print_selname = "<Unknown>";
	}
	}

	DTRACE_PRINTLN4("MG: new MANAGER for %s: screen %d, owner 0x%08lx (@%lu)",
	print_selname, scr,
	mgrown->data.l[2], /* the window owning the selection */
	mgrown->data.l[0]); /* timestamp */
	DTRACE_PRINTLN4("MG: %ld %ld / 0x%lx 0x%lx", /* extra data */
	mgrown->data.l[3], mgrown->data.l[4],
	mgrown->data.l[3], mgrown->data.l[4]);

	if (selname != NULL) {
	XFree(selname);
	}
	}
	#endif /* DEBUG */


	static int
	awt_mgrsel_managed(XClientMessageEvent *mgrown)
	{
	Display *dpy = awt_display;
	struct AwtMgrsel *mgrsel;
	int scr;

	long timestamp;
	Atom selection;
	Window owner;
	long *data;

	if (mgrown->message_type != XA_MANAGER) {
	DTRACE_PRINTLN("MG: ClientMessage type != MANAGER, ignoring");
	return (0);
	}

	scr = awt_mgrsel_screen(mgrown->window);

	#ifdef DEBUG
	awt_mgrsel_dtraceManaged(mgrown);
	#endif

	if (scr < 0) {
	DTRACE_PRINTLN("MG: MANAGER ClientMessage with a non-root window!");
	return (0);
	}

	timestamp = mgrown->data.l[0];
	selection = mgrown->data.l[1];
	owner = mgrown->data.l[2];
	data = &mgrown->data.l[3]; /* long[2], selection specific */

	/* is this a selection we are intrested in? */
	for (mgrsel = mgrsel_list; mgrsel != NULL; mgrsel = mgrsel->next) {
	if (selection == mgrsel->per_scr_atoms[scr])
	break;
	}

	if (mgrsel == NULL) {
	DTRACE_PRINTLN("MG: not interested in this selection, ignoring");
	return (0);
	}


	mgrsel->per_scr_owners[scr] = owner;

	XSelectInput(dpy, owner, StructureNotifyMask \| mgrsel->extra_mask);

	/* notify the listener */
	if (mgrsel->callback_owner != NULL) {
	(*mgrsel->callback_owner)(scr, owner, data, mgrsel->cookie);
	}

	return (1);
	}


	static int
	awt_mgrsel_unmanaged(XDestroyWindowEvent *ev)
	{
	Display *dpy = awt_display;
	struct AwtMgrsel *mgrsel;
	Window exowner;
	int scr;

	exowner = ev->window; /* selection owner that's gone */

	/* is this a selection we are intrested in? */
	for (mgrsel = mgrsel_list; mgrsel != NULL; mgrsel = mgrsel->next) {
	for (scr = 0; scr < ScreenCount(dpy); ++scr) {
	if (exowner == mgrsel->per_scr_owners[scr]) {
	/* can one window own selections for more than one screen? */
	goto out; /* XXX??? */
	}
	}
	}
	out:
	if (mgrsel == NULL) {
	DTRACE_PRINTLN1("MG: DestroyNotify for 0x%08lx ignored", exowner);
	return (0);
	}

	DTRACE_PRINTLN3("MG: DestroyNotify for 0x%08lx, owner of %s at screen %d",
	exowner, mgrsel->selname, scr);

	/* notify the listener (pass exowner as data???) */
	if (mgrsel->callback_owner != NULL) {
	(*mgrsel->callback_owner)(scr, None, NULL, mgrsel->cookie);
	}

	return (1);
	}


	/*
	* Hook to be called from toolkit event loop.
	*/
	int
	awt_mgrsel_processEvent(XEvent *ev)
	{
	Display *dpy = awt_display;
	struct AwtMgrsel *mgrsel;
	int scr;

	if (ev->type == ClientMessage) { /* new manager announces ownership? */
	if (awt_mgrsel_managed(&ev->xclient))
	return (1);
	}

	if (ev->type == DestroyNotify) { /* manager gives up selection? */
	if (awt_mgrsel_unmanaged(&ev->xdestroywindow))
	return (1);
	}

	/* is this an event selected on one of selection owners? */
	for (mgrsel = mgrsel_list; mgrsel != NULL; mgrsel = mgrsel->next) {
	for (scr = 0; scr < ScreenCount(dpy); ++scr) {
	if (ev->xany.window == mgrsel->per_scr_owners[scr]) {
	/* can one window own selections for more than one screen? */
	goto out; /* XXX??? */
	}
	}
	}
	out:
	DTRACE_PRINT2("MG: screen %d, event %d ... ",
	scr, ev->xany.type);
	if (mgrsel == NULL) {
	DTRACE_PRINTLN("ignored");
	return (0); /* not interested */
	}

	DTRACE_PRINT1("%s ... ", mgrsel->selname);
	if (mgrsel->callback_event != NULL) {
	DTRACE_PRINTLN("dispatching");
	(*mgrsel->callback_event)(scr, ev, mgrsel->cookie);
	}
	#ifdef DEBUG
	else {
	DTRACE_PRINTLN("no callback");
	}
	#endif

	return (1);
	}


	void
	awt_mgrsel_init(void)
	{
	static Boolean inited = False;

	Display *dpy = awt_display;
	int scr;

	if (inited) {
	return;
	}

	XA_MANAGER = XInternAtom(dpy, "MANAGER", False);
	DASSERT(XA_MANAGER != None);


	/*
	* Listen for ClientMessage's on each screen's root. We hook into
	* the message loop in the toolkit (with awt_mgrsel_processEvent)
	* to get the events processed. We need this for notifications of
	* new manager acquiring ownership of the manager selection.
	*/
	for (scr = 0; scr < ScreenCount(dpy); ++scr) {
	XSelectInput(dpy, RootWindow(dpy, scr), StructureNotifyMask);
	}

	inited = True;
	}