Handle ICCCM TIMESTAMP selection target

xclib.c

@@ -363,6 +363,7 @@ xcin(Display * dpy,
     static Atom inc;
     static Atom targets;
     static Atom alt_target;
+    static Atom timestamp;
 
     if (!alt_target) {
 	alt_target = XInternAtom(dpy, "STRING", False);
@@ -377,6 +378,10 @@ xcin(Display * dpy,
 	inc = XInternAtom(dpy, "INCR", False);
     }
 
+    if (!timestamp) {
+	timestamp = XInternAtom(dpy, "TIMESTAMP", False);
+    }
+
     /* We consider selections larger than a quarter of the maximum
        request size to be "large". See ICCCM section 2.5 */
     if (!(*chunk_size)) {
@@ -418,8 +423,8 @@ xcin(Display * dpy,
 
 	/* put the data into a property */
 	if (evt.xselectionrequest.target == targets) {
-	    Atom types[3] = { targets, target, alt_target };
-	    int types_count = alt_txt == NULL ? 2 : 3;
+	    Atom types[4] = { targets, target, timestamp, alt_target };
+	    int types_count = alt_txt == NULL ? 3 : 4;
 
 	    if ( xcverb >= ODEBUG ) {
 		fprintf(stderr, "xclib: debug: sending list of TARGETS\n");
@@ -434,6 +439,21 @@ xcin(Display * dpy,
 			    types_count
 		);
 	}
+	else if (evt.xselectionrequest.target == timestamp) {
+	    if ( xcverb >= ODEBUG ) {
+		fprintf(stderr, "xclib: debug: sending TIMESTAMP\n");
+	    }
+
+	    /* Respond with the ownership timestamp as XA_INTEGER 32-bit.
+	     * TIMESTAMP is a single-shot response, no INCR needed. */
+	    long ts = (long) sel_timestamp;
+	    XChangeProperty(dpy,
+			    *win,
+			    *pty,
+			    XA_INTEGER,
+			    32, PropModeReplace, (unsigned char *) &ts,
+			    1);
+	}
 	else if (evt.xselectionrequest.target == alt_target && alt_txt) {
 	    if ( xcverb >= ODEBUG ) {
 		fprintf(stderr, "xclib: debug: sending alternative text\n");
@@ -503,6 +523,10 @@ xcin(Display * dpy,
 	if (evt.xselectionrequest.target == alt_target)
 	    return (1);		/* Finished with request */
 
+	/* don't treat TIMESTAMP request as contents request */
+	if (evt.xselectionrequest.target == timestamp)
+	    return (1);		/* Finished with request */
+
 	/* if len <= chunk_size, then the data was sent all at
 	 * once and the transfer is now complete, return 1
 	 */

xclib.h

@@ -24,6 +24,9 @@
 /* global verbosity output level */
 extern int xcverb;
 
+/* ownership timestamp for ICCCM TIMESTAMP target */
+extern Time sel_timestamp;
+
 /* global error flags from xchandler() */
 extern int xcerrflag;
 extern XErrorEvent xcerrevt;

xclip.c

@@ -55,6 +55,7 @@ static int frmnl = F;		/* remove (single) newline character at the very end if p
 static int fsecm = F;		/* zero out selection buffer before exiting */
 
 Display *dpy;			/* connection to X11 display */
+Time sel_timestamp = CurrentTime;  /* ownership timestamp for ICCCM TIMESTAMP target */
 XrmDatabase opt_db = NULL;	/* database for options */
 
 char **fil_names;		/* names of files to read */
@@ -366,6 +367,26 @@ doOptTarget(void)
     }
 }
 
+/* Acquire a real X server timestamp per ICCCM §2.1:
+ * do a zero-length property append, then wait for PropertyNotify. */
+static Time
+acquire_timestamp(Display *dpy, Window win)
+{
+    Atom ts_atom = XInternAtom(dpy, "XCLIP_TIMESTAMP_PROP", False);
+    XEvent evt;
+
+    XSelectInput(dpy, win, PropertyChangeMask);
+    XChangeProperty(dpy, win, ts_atom, XA_INTEGER, 32, PropModeAppend, NULL, 0);
+    XFlush(dpy);
+    while (1) {
+	XNextEvent(dpy, &evt);
+	if (evt.type == PropertyNotify) {
+	    XDeleteProperty(dpy, win, ts_atom);
+	    return evt.xproperty.time;
+	}
+    }
+}
+
 static int
 doIn(Window win, const char *progname)
 {
@@ -472,8 +493,8 @@ doIn(Window win, const char *progname)
     /* take control of the selection so that we receive
      * SelectionRequest events from other windows
      */
-    /* FIXME: Should not use CurrentTime, according to ICCCM section 2.1 */
-    XSetSelectionOwner(dpy, sseln, win, CurrentTime);
+    sel_timestamp = acquire_timestamp(dpy, win);
+    XSetSelectionOwner(dpy, sseln, win, sel_timestamp);
 
     /* Double-check SetSelectionOwner did not "merely appear to succeed". */
     Window owner = XGetSelectionOwner(dpy, sseln);

xctest

@@ -61,6 +61,41 @@ else
     echo "PASS: xclip exited correctly after losing selection"
 fi
 
+# test that TARGETS response includes TIMESTAMP when xclip owns a selection
+echo "Testing that TARGETS response includes TIMESTAMP"
+printf '%s' "  xclip -o -sel clipboard -t TARGETS includes TIMESTAMP	"
+echo "test data" | $checker ./xclip -sel clipboard -i
+sleep "$delay"
+actual=$($checker ./xclip -o -sel clipboard -t TARGETS)
+if echo "$actual" | grep -qx TIMESTAMP; then
+    echo "PASS"
+else
+    echo "FAIL: TARGETS output was:"
+    echo "$actual"
+    exit 1
+fi
+
+# test that TIMESTAMP target returns a positive integer, not raw clipboard data
+echo "Testing that TIMESTAMP target returns a positive integer"
+printf '%s' "  xclip -o -sel clipboard -t TIMESTAMP returns a positive integer	"
+echo "test data" | $checker ./xclip -sel clipboard -i
+sleep "$delay"
+actual=$($checker ./xclip -o -sel clipboard -t TIMESTAMP)
+case "$actual" in
+    "" | *[!0-9]*)
+        echo "FAIL: expected a positive integer, got: $actual"
+        exit 1
+        ;;
+    *)
+        if [ "$actual" -gt 0 ]; then
+            echo "PASS"
+        else
+            echo "FAIL: expected a positive integer, got: $actual"
+            exit 1
+        fi
+        ;;
+esac
+
 # temp file names (in and out)
 tempi=`mktemp` || exit 1
 tempo=`mktemp` || exit 1