From f6b03f106c0cd2a225b528c972840204103e58a6 Mon Sep 17 00:00:00 2001
From: Kenny Levinsen <kl@kl.wtf>
Date: Tue, 14 Jan 2020 19:42:15 +0100
Subject: [PATCH 1/5] wayland: Cancel display read before abortOnFatalError

Calling wl_display_cancel_read immediately ensures that other readers
waiting on us will have a chance to wake up and discover the error in a
timely manner.
---
 glfw/wl_window.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/glfw/wl_window.c b/glfw/wl_window.c
index 505d84829..cdc6ef0cf 100644
--- a/glfw/wl_window.c
+++ b/glfw/wl_window.c
@@ -782,8 +782,8 @@ handleEvents(monotonic_t timeout)
     errno = 0;
     if (wl_display_flush(display) < 0 && errno != EAGAIN)
     {
-        abortOnFatalError(errno);
         wl_display_cancel_read(display);
+        abortOnFatalError(errno);
         return;
     }
 

From 4acab650160f38d0d7c7121cf8f252c6a4d6c4ae Mon Sep 17 00:00:00 2001
From: Kenny Levinsen <kl@kl.wtf>
Date: Tue, 14 Jan 2020 19:42:51 +0100
Subject: [PATCH 2/5] wayland: Only cancel display read after prepare success

The display reader count only increments when wl_display_prepare_read
succeeds.  Calling wl_display_cancel_read when wl_display_prepare_read
has not succeeded results in a negative reader count, which does not
have well-defined behavior.
---
 glfw/wl_window.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/glfw/wl_window.c b/glfw/wl_window.c
index cdc6ef0cf..e82fda793 100644
--- a/glfw/wl_window.c
+++ b/glfw/wl_window.c
@@ -768,7 +768,6 @@ handleEvents(monotonic_t timeout)
             if (num_dispatched < 0) {
                 if (errno == EAGAIN) continue;
                 int last_error = wl_display_get_error(display);
-                wl_display_cancel_read(display);
                 if (last_error) abortOnFatalError(last_error);
                 return;
             }

From bc24716476187453e61038eee6ed24f3d0821733 Mon Sep 17 00:00:00 2001
From: Kenny Levinsen <kl@kl.wtf>
Date: Tue, 14 Jan 2020 19:54:48 +0100
Subject: [PATCH 3/5] wayland: errno does not have to be cleared

As long as errno is only read on error from an errno-setting function,
then there is no need to reset errno between uses.
---
 glfw/wl_window.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/glfw/wl_window.c b/glfw/wl_window.c
index e82fda793..61b407dd8 100644
--- a/glfw/wl_window.c
+++ b/glfw/wl_window.c
@@ -763,7 +763,6 @@ handleEvents(monotonic_t timeout)
 
     while (wl_display_prepare_read(display) != 0) {
         while(1) {
-            errno = 0;
             int num_dispatched = wl_display_dispatch_pending(display);
             if (num_dispatched < 0) {
                 if (errno == EAGAIN) continue;
@@ -778,7 +777,6 @@ handleEvents(monotonic_t timeout)
     // If an error different from EAGAIN happens, we have likely been
     // disconnected from the Wayland session, try to handle that the best we
     // can.
-    errno = 0;
     if (wl_display_flush(display) < 0 && errno != EAGAIN)
     {
         wl_display_cancel_read(display);

From 083b294659b33a43815b1db384ccac446f55efe0 Mon Sep 17 00:00:00 2001
From: Kenny Levinsen <kl@kl.wtf>
Date: Tue, 14 Jan 2020 19:47:17 +0100
Subject: [PATCH 4/5] wayland: Simplify dispatch_pending error handling

wl_display_dispatch_pending does not return EAGAIN, and always sets an
error when it fails. This allows us to handle errors in a simpler
manner.
---
 glfw/wl_window.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/glfw/wl_window.c b/glfw/wl_window.c
index 61b407dd8..a31a37dad 100644
--- a/glfw/wl_window.c
+++ b/glfw/wl_window.c
@@ -762,15 +762,9 @@ handleEvents(monotonic_t timeout)
     EVDBG("starting handleEvents(%.2f)", monotonic_t_to_s_double(timeout));
 
     while (wl_display_prepare_read(display) != 0) {
-        while(1) {
-            int num_dispatched = wl_display_dispatch_pending(display);
-            if (num_dispatched < 0) {
-                if (errno == EAGAIN) continue;
-                int last_error = wl_display_get_error(display);
-                if (last_error) abortOnFatalError(last_error);
-                return;
-            }
-            break;
+        if (wl_display_dispatch_pending(display) == -1) {
+            abortOnFatalError(wl_display_get_error(display));
+            return;
         }
     }
 

From ca7cab1a2d9f7d0e0ac2c1152251bde7ee8d10f5 Mon Sep 17 00:00:00 2001
From: Kenny Levinsen <kl@kl.wtf>
Date: Tue, 14 Jan 2020 20:06:13 +0100
Subject: [PATCH 5/5] wayland: Consistently use errno for errors

---
 glfw/wl_window.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/glfw/wl_window.c b/glfw/wl_window.c
index a31a37dad..3d16da8ae 100644
--- a/glfw/wl_window.c
+++ b/glfw/wl_window.c
@@ -763,7 +763,7 @@ handleEvents(monotonic_t timeout)
 
     while (wl_display_prepare_read(display) != 0) {
         if (wl_display_dispatch_pending(display) == -1) {
-            abortOnFatalError(wl_display_get_error(display));
+            abortOnFatalError(errno);
             return;
         }
     }