[client] clipboard: suppress Wayland self-copy feedback

client/displayservers/Wayland/clipboard.c

@@ -192,6 +192,15 @@ static bool hasImageMimetype(char ** mimetypes)
   return false;
 }
 
+enum ClipboardInvalidateMode
+{
+  CLIPBOARD_INVALIDATE_SILENT,
+  CLIPBOARD_INVALIDATE_CONDITIONAL,
+  CLIPBOARD_INVALIDATE_FORCE,
+};
+
+static void waylandCBInvalidateLocal(enum ClipboardInvalidateMode mode);
+
 /* wlCb.lock must be held. */
 static struct ClipboardRead * clipboardReadTakeCurrentNL(void)
 {
@@ -312,14 +321,15 @@ static void dataDeviceHandleSelection(void * opaque,
     LG_LOCK(wlCb.lock);
     wlCb.selectionSource = NULL;
     LG_UNLOCK(wlCb.lock);
-    waylandCBInvalidate();
+    waylandCBInvalidateLocal(CLIPBOARD_INVALIDATE_FORCE);
     return;
   }
 
   struct DataOffer * extra = wl_data_offer_get_user_data(offer);
-  if (!hasAnyMimetype(extra->mimetypes) || extra->isSelfCopy)
+  const bool selfCopy = extra->isSelfCopy;
+  if (!hasAnyMimetype(extra->mimetypes) || selfCopy)
   {
-    if (!extra->isSelfCopy)
+    if (!selfCopy)
     {
       LG_LOCK(wlCb.lock);
       wlCb.selectionSource = NULL;
@@ -329,7 +339,12 @@ static void dataDeviceHandleSelection(void * opaque,
     for (enum LG_ClipboardData i = 0; i < LG_CLIPBOARD_DATA_NONE; ++i)
       free(extra->mimetypes[i]);
     free(extra);
-    waylandCBInvalidate();
+    if (!selfCopy)
+      waylandCBInvalidateLocal(CLIPBOARD_INVALIDATE_FORCE);
+    else
+      /* This is the compositor echoing the source we just installed. It is
+       * not a new local clipboard owner and must not send a provider CLEAR. */
+      waylandCBInvalidateLocal(CLIPBOARD_INVALIDATE_SILENT);
     wl_data_offer_destroy(offer);
     return;
   }
@@ -647,7 +662,7 @@ static void clipboardReadCallback(uint32_t events, void * opaque)
   }
 }
 
-void waylandCBInvalidate(void)
+static void waylandCBInvalidateLocal(enum ClipboardInvalidateMode mode)
 {
   char * mimetypes[LG_CLIPBOARD_DATA_NONE];
   LG_LOCK(wlCb.lock);
@@ -656,16 +671,27 @@ void waylandCBInvalidate(void)
   wlCb.offer = NULL;
   memcpy(mimetypes, wlCb.mimetypes, sizeof(mimetypes));
   memset(wlCb.mimetypes, 0, sizeof(wlCb.mimetypes));
+  const bool hadLocal = read || offer || hasAnyMimetype(mimetypes);
+  const bool notifyProvider = mode == CLIPBOARD_INVALIDATE_FORCE ||
+    (mode == CLIPBOARD_INVALIDATE_CONDITIONAL && hadLocal);
+  const LG_ClipboardRequest request = read ? read->request :
+    LG_CLIPBOARD_REQUEST_INVALID;
+  if (read)
+    clipboardReadRetire(read);
+
+  /* Serialize the provider release with source publication. Clipboard
+   * provider operations may not synchronously deliver event callbacks, so
+   * calling this while holding wlCb.lock cannot re-enter the display server. */
+  if (notifyProvider)
+  {
+    if (read)
+      lgClipboard_abort(request);
+    lgClipboard_release();
+  }
   LG_UNLOCK(wlCb.lock);
 
-  if (read)
-  {
-    const LG_ClipboardRequest request = read->request;
-    clipboardReadRetire(read);
+  if (read && !notifyProvider)
     lgClipboard_abort(request);
-  }
-
-  lgClipboard_release();
 
   if (offer)
     wl_data_offer_destroy(offer);
@@ -673,6 +699,11 @@ void waylandCBInvalidate(void)
     free(mimetypes[i]);
 }
 
+void waylandCBInvalidate(void)
+{
+  waylandCBInvalidateLocal(CLIPBOARD_INVALIDATE_CONDITIONAL);
+}
+
 void waylandCBRequest(LG_ClipboardRequest request, LG_ClipboardData type)
 {
   if (request == LG_CLIPBOARD_REQUEST_INVALID ||
@@ -1186,6 +1217,11 @@ static void waylandCBPublish(LG_ClipboardData type)
     wl_data_source_offer(source, *mimetype);
   wl_data_source_offer(source, wlCb.lgMimetype);
 
+  /* Publishing a remote selection supersedes the old external offer. Retire
+   * it before set_selection so a simultaneous focus loss cannot release the
+   * provider while this remote source is active. */
+  waylandCBInvalidateLocal(CLIPBOARD_INVALIDATE_SILENT);
+
   LG_LOCK(wlCb.lock);
   if (wlCb.dataDevice)
   {
@@ -1194,13 +1230,13 @@ static void waylandCBPublish(LG_ClipboardData type)
     wlCb.selectionSource   = source;
     wl_data_device_set_selection(wlCb.dataDevice, source,
       wlWm.keyboardEnterSerial);
-  }
-  else
-  {
-    wl_data_source_destroy(source);
-    free(transfer);
+    LG_UNLOCK(wlCb.lock);
+    return;
   }
   LG_UNLOCK(wlCb.lock);
+
+  wl_data_source_destroy(source);
+  free(transfer);
 }
 
 void waylandCBNotice(LG_ClipboardData type)

client/src/clipboard.c

@@ -485,6 +485,10 @@ static void eventNotice(void * opaque,
   generation = clipboard.remoteGeneration;
   transfer = clearRemoteRequestNL();
   notice = clipboard.localAvailable && g_params.clipboardToLocal;
+  /* Once published, the remote notice replaces the local clipboard. Do not
+   * replay that stale local offer if the provider is rebound. */
+  if (notice)
+    clipboard.localTypeCount = 0;
   LG_UNLOCK(clipboard.stateLock);
   LG_UNLOCK(clipboard.requestLock);
 
@@ -1222,6 +1226,10 @@ void lgClipboard_setLocalAvailable(bool available)
   notice = available && clipboard.remoteNotice &&
     g_params.clipboardToLocal;
   type = clipboard.remoteType;
+  /* A pending remote notice replaces the local clipboard when it becomes
+   * publishable. Do not replay the superseded local offer afterwards. */
+  if (notice)
+    clipboard.localTypeCount = 0;
   if (!available)
     transfer = clearRemoteRequestNL();
   LG_UNLOCK(clipboard.stateLock);

client/tests/CMakeLists.txt

@@ -211,6 +211,8 @@ if(ENABLE_WAYLAND)
     teardown
     teardown-external
     self-copy
+    ignored
+    invalidate-lock
     dnd
   )
   foreach(name IN LISTS WAYLAND_CLIPBOARD_CASES)
@@ -471,6 +473,8 @@ target_link_libraries(clipboard-tests
 set(CLIPBOARD_CASES
   preference
   request
+  remote-local
+  pending-remote
   invalid
   cancel
   generation

client/tests/clipboard_test.c

@@ -627,6 +627,64 @@ static void testRequest(void)
   lgClipboard_free();
 }
 
+static void testRemoteReplacesLocal(void)
+{
+  init();
+  bind(&p);
+  const LG_ClipboardData types[] = { LG_CLIPBOARD_DATA_TEXT };
+
+  lgClipboard_notifyTypes(types, 1);
+  CHECK(p.notice == 1);
+
+  g_params.clipboardToLocal = false;
+  notice(&p, types, 1);
+  CHECK(d.notice == 0);
+
+  /* A notice which is not published locally must not discard the local
+   * clipboard advertised towards the guest. */
+  lgClipboard_setTransport(&plainOps, &q);
+  CHECK(q.attach == 1);
+  CHECK(q.notice == 1);
+  CHECK(q.release == 0);
+
+  g_params.clipboardToLocal = true;
+  notice(&q, types, 1);
+  CHECK(d.notice == 1);
+
+  /* Rebinding after a remote notice must not replay the superseded local
+   * offer back to the provider. */
+  lgClipboard_setTransport(&plainOps, &r);
+  CHECK(r.attach == 1);
+  CHECK(r.notice == 0);
+  CHECK(r.release == 1);
+
+  lgClipboard_free();
+}
+
+static void testPendingRemoteReplacesLocal(void)
+{
+  init();
+  bind(&p);
+  const LG_ClipboardData types[] = { LG_CLIPBOARD_DATA_TEXT };
+
+  lgClipboard_notifyTypes(types, 1);
+  CHECK(p.notice == 1);
+  lgClipboard_setLocalAvailable(false);
+
+  notice(&p, types, 1);
+  CHECK(d.notice == 0);
+
+  lgClipboard_setLocalAvailable(true);
+  CHECK(d.notice == 1);
+
+  lgClipboard_setTransport(&plainOps, &q);
+  CHECK(q.attach == 1);
+  CHECK(q.notice == 0);
+  CHECK(q.release == 1);
+
+  lgClipboard_free();
+}
+
 static void testInvalid(void)
 {
   init();
@@ -1071,6 +1129,8 @@ static const struct Test tests[] =
 {
   { "preference", testPreference },
   { "request"   , testRequest    },
+  { "remote-local", testRemoteReplacesLocal },
+  { "pending-remote", testPendingRemoteReplacesLocal },
   { "invalid"   , testInvalid    },
   { "cancel"    , testCancel     },
   { "generation", testGeneration },

client/tests/wayland_clipboard_test.c

@@ -155,7 +155,9 @@ struct Log
   bool                 requestOK;
   bool                 requestCancelSync;
   bool                 requestBeginSync;
+  bool                 expectReleaseLocked;
   bool                 firing;
+  unsigned int         releaseLockedN;
 };
 
 struct WaylandDSState wlWm;
@@ -440,6 +442,12 @@ void lgClipboard_notifyTypes(
 
 void lgClipboard_release(void)
 {
+  if (rec.expectReleaseLocked)
+  {
+    CHECK(atomic_flag_test_and_set_explicit(
+        &wlCb.lock, memory_order_acquire));
+    ++rec.releaseLockedN;
+  }
   ++rec.releaseN;
 }
 
@@ -690,11 +698,72 @@ static void testMime(void)
 }
 
 static void testSelfCopy(void)
+{
+  start();
+  struct Proxy * local = textOffer();
+  CHECK(rec.noticeN == 1);
+
+  waylandCBNotice(LG_CLIPBOARD_DATA_TEXT);
+  struct Proxy * source = &proto.source[0];
+  CHECK(wlCb.selectionSource == (struct wl_data_source *)source);
+
+  /* Losing focus before the compositor echoes our source must not release
+   * the remote clipboard. */
+  waylandCBInvalidate();
+  CHECK(rec.releaseN == 0);
+  CHECK(wlCb.selectionSource == (struct wl_data_source *)source);
+
+  struct Proxy * echo = newOffer();
+  offerMime(echo, "text/plain");
+  offerMime(echo, wlCb.lgMimetype);
+  selectOffer(echo);
+
+  CHECK(rec.noticeN == 1);
+  CHECK(rec.releaseN == 0);
+  CHECK(wlCb.selectionSource == (struct wl_data_source *)source);
+  CHECK(!wlCb.offer);
+  for (enum LG_ClipboardData i = 0; i < LG_CLIPBOARD_DATA_NONE; ++i)
+    CHECK(!wlCb.mimetypes[i]);
+  CHECK(local->dead);
+  CHECK(echo->dead);
+  CHECK(proto.offerDestroyN == 2);
+  CHECK(!echo->user);
+
+  waylandCBInvalidate();
+  CHECK(rec.releaseN == 0);
+  CHECK(wlCb.selectionSource == (struct wl_data_source *)source);
+
+  int fds[2];
+  CHECK(pipe(fds) == 0);
+  sourceListener(source)->send(source->data,
+      (struct wl_data_source *)source, "text/plain", fds[1]);
+  CHECK(rec.requestN == 1);
+  CHECK(rec.requestType == LG_CLIPBOARD_DATA_TEXT);
+  CHECK(rec.requestStream);
+  CHECK(rec.requestOpaque);
+  CHECK(rec.requestStream->begin(rec.requestOpaque,
+      LG_CLIPBOARD_DATA_TEXT, LG_CLIPBOARD_SIZE_UNKNOWN) ==
+      LG_CLIPBOARD_RESULT_ACCEPTED);
+  CHECK(rec.requestStream->end(rec.requestOpaque, 0) ==
+      LG_CLIPBOARD_RESULT_ACCEPTED);
+  uint8_t value;
+  CHECK(read(fds[0], &value, 1) == 0);
+  CHECK(close(fds[0]) == 0);
+  checkClosed(fds[1]);
+
+  selectOffer(NULL);
+  CHECK(rec.releaseN == 1);
+  CHECK(!wlCb.selectionSource);
+
+  CHECK(proto.dirtyDestroyN == 0);
+  finish();
+}
+
+static void testIgnoredOffer(void)
 {
   start();
   struct Proxy * offer = newOffer();
-  offerMime(offer, "text/plain");
-  offerMime(offer, wlCb.lgMimetype);
+  offerMime(offer, "application/x-unsupported");
   selectOffer(offer);
 
   CHECK(rec.noticeN == 0);
@@ -706,6 +775,21 @@ static void testSelfCopy(void)
   finish();
 }
 
+static void testInvalidateSerialization(void)
+{
+  start();
+  struct Proxy * offer = textOffer();
+  rec.expectReleaseLocked = true;
+
+  waylandCBInvalidate();
+
+  CHECK(rec.releaseN == 1);
+  CHECK(rec.releaseLockedN == 1);
+  CHECK(offer->dead);
+  CHECK(!wlCb.offer);
+  finish();
+}
+
 static void testReplace(void)
 {
   start();
@@ -1245,6 +1329,8 @@ static const struct Test tests[] =
   { "teardown"  , testTeardown  },
   { "teardown-external", testTeardownExternalOwner },
   { "self-copy" , testSelfCopy  },
+  { "ignored"   , testIgnoredOffer },
+  { "invalidate-lock", testInvalidateSerialization },
   { "dnd"       , testDnd       },
 };