From 69e0902cfc36b338701f167bf310938f397122ea Mon Sep 17 00:00:00 2001
From: hujianwei <hujianwei@localhost.localdomain>
Date: Thu, 17 Nov 2022 02:26:27 +0000
Subject: [PATCH] Implement wl_output version 4

* 12to11.man:
* README: Update documentation.
* output.c (struct _Output): Rearrange structure for alignment.
(HandleBind): Send output name if necessary.
(CompareOutputs): Handle name changes separately.
(MakeGlobal): Support version 4 or later.
(SendUpdates): Handle name changes separately.
---
 12to11.man |  2 +-
 README     |  2 +-
 output.c   | 35 +++++++++++++++++++++++++----------
 3 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/12to11.man b/12to11.man
index 9b1cac2..54e0c0d 100644
--- a/12to11.man
+++ b/12to11.man
@@ -260,7 +260,7 @@ following Wayland interfaces:
 lb lb
 lb n .
 Protocol	Version
-wl_output	2
+wl_output	4
 wl_compositor	5
 wl_shm	1
 xdg_wm_base	5
diff --git a/README b/README
index 2168677..928ec85 100644
--- a/README
+++ b/README
@@ -52,7 +52,7 @@ the "renderer" resource (class "Renderer") to "egl".
 The following Wayland protocols are implemented to a more-or-less
 complete degree:
 
-  'wl_output',                                  version:  2
+  'wl_output',                                  version:  4
   'wl_compositor',                              version:  5
   'wl_shm',                                     version:  1
   'xdg_wm_base',                                version:  5
diff --git a/output.c b/output.c
index 398fc12..ab74acd 100644
--- a/output.c
+++ b/output.c
@@ -39,9 +39,6 @@ struct _Output
   /* The output ID of this output.  */
   RROutput output;
 
-  /* Physical height of this output.  */
-  unsigned int mm_width, mm_height;
-
   /* List of display modes.  */
   XLList *modes;
 
@@ -51,15 +48,18 @@ struct _Output
   /* A list of resources associated with this output.  */
   XLList *resources;
 
+  /* The name of the output.  */
+  char *name;
+
+  /* Physical height of this output.  */
+  unsigned int mm_width, mm_height;
+
   /* The X and Y position of this output.  */
   int x, y;
 
   /* The width and height of this output.  */
   int width, height;
 
-  /* The name of the output.  */
-  char *name;
-
   /* The transform and subpixel layout of this output.  */
   uint32_t transform, subpixel;
 
@@ -83,10 +83,11 @@ enum
   {
     ModesChanged    = 1,
     GeometryChanged = (1 << 2),
+    NameChanged	    = (1 << 3),
     /* N.B. that this isn't currently checked during comparisons,
        since the rest of the code only supports a single global
        scale.  */
-    ScaleChanged    = (1 << 3),
+    ScaleChanged    = (1 << 4),
   };
 
 /* List of all outputs registered.  */
@@ -271,6 +272,11 @@ HandleBind (struct wl_client *client, void *data,
   for (tem = output->modes; tem; tem = tem->next)
     SendMode (tem->data, resource);
 
+  /* Send the output name.  I think it is supposed to be unique.  */
+
+  if (wl_resource_get_version (resource) >= 3)
+    wl_output_send_name (resource, output->name);
+
   if (wl_resource_get_version (resource) >= 2)
     wl_output_send_done (resource);
 
@@ -530,10 +536,12 @@ CompareOutputs (Output *output, Output *other, int *flags)
       || output->x != other->x
       || output->y != other->y
       || output->subpixel != other->subpixel
-      || output->transform != other->transform
-      || !strcmp (output->name, other->name))
+      || output->transform != other->transform)
     difference |= GeometryChanged;
 
+  if (strcmp (output->name, other->name))
+    difference |= NameChanged;
+
   *flags = difference;
 }
 
@@ -560,7 +568,7 @@ MakeGlobal (Output *output)
   XLAssert (!output->global);
 
   output->global = wl_global_create (compositor.wl_display,
-				     &wl_output_interface, 2,
+				     &wl_output_interface, 4,
 				     output, HandleBind);
 
   if (!output->global)
@@ -585,11 +593,18 @@ SendUpdates (Output *output, int difference)
   if (!difference)
     return;
 
+  /* Given a mask of differences, send the updated output information
+     to all clients.  */
+
   for (tem = output->resources; tem; tem = tem->next)
     {
       if (difference & GeometryChanged)
 	SendGeometry (output, tem->data);
 
+      if (difference & NameChanged
+	  && wl_resource_get_version (tem->data) >= 3)
+	wl_output_send_name (tem->data, output->name);
+
       if (difference & ModesChanged)
 	{
 	  for (tem1 = output->modes; tem1; tem1 = tem->next)