From ef9c3ef1cbb57afa2f64a70282fffe33e5519dfe Mon Sep 17 00:00:00 2001
From: Aleksei Bavshin <alebastr89@gmail.com>
Date: Wed, 6 Jan 2021 07:03:14 -0800
Subject: [PATCH 1/2] fix(wlr/taskbar): fix wl_array out-of-bounds access

wl_array->size contains the number of bytes in the array instead of the
number of elements.
---
 src/modules/wlr/taskbar.cpp | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/modules/wlr/taskbar.cpp b/src/modules/wlr/taskbar.cpp
index e70ad9c3..46147bd0 100644
--- a/src/modules/wlr/taskbar.cpp
+++ b/src/modules/wlr/taskbar.cpp
@@ -367,16 +367,16 @@ void Task::handle_output_leave(struct wl_output *output)
 void Task::handle_state(struct wl_array *state)
 {
     state_ = 0;
-    for (auto* entry = static_cast<uint32_t*>(state->data);
-         entry < static_cast<uint32_t*>(state->data) + state->size;
-         entry++) {
-        if (*entry == ZWLR_FOREIGN_TOPLEVEL_HANDLE_V1_STATE_MAXIMIZED)
+    size_t size = state->size / sizeof(uint32_t);
+    for (size_t i = 0; i < size; ++i) {
+        auto entry = static_cast<uint32_t*>(state->data)[i];
+        if (entry == ZWLR_FOREIGN_TOPLEVEL_HANDLE_V1_STATE_MAXIMIZED)
             state_ |= MAXIMIZED;
-        if (*entry == ZWLR_FOREIGN_TOPLEVEL_HANDLE_V1_STATE_MINIMIZED)
+        if (entry == ZWLR_FOREIGN_TOPLEVEL_HANDLE_V1_STATE_MINIMIZED)
             state_ |= MINIMIZED;
-        if (*entry == ZWLR_FOREIGN_TOPLEVEL_HANDLE_V1_STATE_ACTIVATED)
+        if (entry == ZWLR_FOREIGN_TOPLEVEL_HANDLE_V1_STATE_ACTIVATED)
             state_ |= ACTIVE;
-        if (*entry == ZWLR_FOREIGN_TOPLEVEL_HANDLE_V1_STATE_FULLSCREEN)
+        if (entry == ZWLR_FOREIGN_TOPLEVEL_HANDLE_V1_STATE_FULLSCREEN)
             state_ |= FULLSCREEN;
     }
 }

From b79301a5bdafb2d0a7764990530898996a97c386 Mon Sep 17 00:00:00 2001
From: Aleksei Bavshin <alebastr89@gmail.com>
Date: Fri, 8 Jan 2021 15:07:04 -0800
Subject: [PATCH 2/2] fix(wlr/taskbar): protocol error when reconnecting
 outputs

Destroy request is not specified for foreign toplevel manager and it
does not prevent the compositor from sending more events.
Libwayland would ignore events to a destroyed objects, but that could
indirectly cause a gap in the sequence of new object ids and trigger
error condition in the library.

With this commit waybar sends a `stop` request to notify the compositor
about the destruction of a toplevel manager. That fixes abnormal
termination of the bar with following errors:
```
(waybar:11791): Gdk-DEBUG: 20:04:19.778: not a valid new object id (4278190088), message toplevel(n)

Gdk-Message: 20:04:19.778: Error reading events from display: Invalid argument
```
---
 src/modules/wlr/taskbar.cpp | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/modules/wlr/taskbar.cpp b/src/modules/wlr/taskbar.cpp
index 46147bd0..4cbb8ce6 100644
--- a/src/modules/wlr/taskbar.cpp
+++ b/src/modules/wlr/taskbar.cpp
@@ -637,8 +637,20 @@ Taskbar::Taskbar(const std::string &id, const waybar::Bar &bar, const Json::Valu
 Taskbar::~Taskbar()
 {
     if (manager_) {
-        zwlr_foreign_toplevel_manager_v1_destroy(manager_);
-        manager_ = nullptr;
+        struct wl_display *display = Client::inst()->wl_display;
+        /*
+         * Send `stop` request and wait for one roundtrip.
+         * This is not quite correct as the protocol encourages us to wait for the .finished event,
+         * but it should work with wlroots foreign toplevel manager implementation.
+         */
+        zwlr_foreign_toplevel_manager_v1_stop(manager_);
+        wl_display_roundtrip(display);
+
+        if (manager_) {
+            spdlog::warn("Foreign toplevel manager destroyed before .finished event");
+            zwlr_foreign_toplevel_manager_v1_destroy(manager_);
+            manager_ = nullptr;
+        }
     }
 }