Add --diagnostics option

It will cause compton to print out some rudimentary diagnostics.

Also small improvements of the meson.build.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

.github/issue_template.md

@@ -10,7 +10,8 @@
 // Tell us something about the desktop environment you are using, for example: i3-gaps, Gnome Shell, etc.
 
 ### Compton version
-// You can run `compton --version` to get that
+// Put the output of `compton --version` here.
+// If you are running compton v4 or later, please also include the output of `compton --diagnostics`
 // Example: v1
 
 ### Compton configuration:

README.md

@@ -25,6 +25,7 @@ Assuming you already have all the usual building tools installed (e.g. gcc, meso
 * xcb-randr
 * xcb-composite
 * xcb-image
+* xcb-present
 * xcb-xinerama (optional, disable with `-Dxinerama=false` meson configure flag)
 * pixman
 * libdbus (optional, disable with the `-Ddbus=false` meson configure flag)

meson.build

@@ -37,7 +37,7 @@ endif
 
 add_global_arguments('-D_GNU_SOURCE', language: 'c')
 
-warns = [ 'all', 'extra', 'no-unused-parameter', 'nonnull', 'shadow' ]
+warns = [ 'all', 'extra', 'no-unused-parameter', 'nonnull', 'shadow', 'implicit-fallthrough' ]
 foreach w : warns
 	if cc.has_argument('-W'+w)
 		add_global_arguments('-W'+w, language: 'c')

src/common.h

@@ -436,6 +436,7 @@ typedef struct ev_session_prepare ev_session_prepare;
 typedef struct options_t {
   // === Debugging ===
   bool monitor_repaint;
+  bool print_diagnostics;
   // === General ===
   /// The configuration file we used.
   char *config_file;
@@ -864,6 +865,8 @@ typedef struct session {
   int randr_event;
   /// Error base number for X RandR extension.
   int randr_error;
+  /// Whether X Present extension exists.
+  bool present_exists;
 #ifdef CONFIG_OPENGL
   /// Whether X GLX extension exists.
   bool glx_exists;

src/compton.c

@@ -12,6 +12,7 @@
 #include <ctype.h>
 #include <string.h>
 #include <xcb/randr.h>
+#include <xcb/present.h>
 #include <xcb/damage.h>
 #include <xcb/render.h>
 #include <xcb/xcb_image.h>
@@ -25,6 +26,7 @@
 #include "win.h"
 #include "x.h"
 #include "config.h"
+#include "diagnostic.h"
 
 static void
 finish_destroy_win(session_t *ps, win **_w);
@@ -3696,6 +3698,7 @@ get_cfg(session_t *ps, int argc, char *const *argv, bool first_pass) {
     { "reredir-on-root-change", no_argument, NULL, 731 },
     { "glx-reinit-on-root-change", no_argument, NULL, 732 },
     { "monitor-repaint", no_argument, NULL, 800 },
+    { "diagnostics", no_argument, NULL, 801 },
     // Must terminate with a NULL entry
     { NULL, 0, NULL, 0 },
   };
@@ -3983,6 +3986,9 @@ get_cfg(session_t *ps, int argc, char *const *argv, bool first_pass) {
       P_CASEBOOL(731, reredir_on_root_change);
       P_CASEBOOL(732, glx_reinit_on_root_change);
       P_CASEBOOL(800, monitor_repaint);
+      case 801:
+        ps->o.print_diagnostics = true;
+        break;
       default:
         usage(1);
         break;
@@ -5050,6 +5056,7 @@ session_init(session_t *ps_old, int argc, char **argv) {
   xcb_prefetch_extension_data(ps->c, &xcb_xfixes_id);
   xcb_prefetch_extension_data(ps->c, &xcb_randr_id);
   xcb_prefetch_extension_data(ps->c, &xcb_xinerama_id);
+  xcb_prefetch_extension_data(ps->c, &xcb_present_id);
 
   ext_info = xcb_get_extension_data(ps->c, &xcb_render_id);
   if (!ext_info || !ext_info->present) {
@@ -5133,17 +5140,25 @@ session_init(session_t *ps_old, int argc, char **argv) {
     ps->shape_exists = true;
   }
 
-  // Query X RandR
-  if ((ps->o.sw_opti && !ps->o.refresh_rate) || ps->o.xinerama_shadow_crop) {
   ext_info = xcb_get_extension_data(ps->c, &xcb_randr_id);
   if (ext_info && ext_info->present) {
     ps->randr_exists = true;
     ps->randr_event = ext_info->first_event;
     ps->randr_error = ext_info->first_error;
-    } else
+  }
+
+  ext_info = xcb_get_extension_data(ps->c, &xcb_present_id);
+  if (ext_info && ext_info->present) {
+    ps->present_exists = true;
+  }
+
+  // Query X RandR
+  if ((ps->o.sw_opti && !ps->o.refresh_rate) || ps->o.xinerama_shadow_crop) {
+    if (!ps->randr_exists) {
       printf_errf("(): No XRandR extension, automatic screen change "
           "detection impossible.");
     }
+  }
 
   // Query X Xinerama extension
   if (ps->o.xinerama_shadow_crop) {
@@ -5161,6 +5176,11 @@ session_init(session_t *ps_old, int argc, char **argv) {
   // of OpenGL context.
   init_overlay(ps);
 
+  if (ps->o.print_diagnostics) {
+    print_diagnostics(ps);
+    exit(0);
+  }
+
   // Initialize OpenGL as early as possible
   if (bkend_use_glx(ps)) {
 #ifdef CONFIG_OPENGL

src/diagnostic.c

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright (c) 2018 Yuxuan Shui <yshuiv7@gmail.com>
+
+#include "diagnostic.h"
+#include "common.h"
+
+void print_diagnostics(session_t *ps) {
+	printf("**Version:** " COMPTON_VERSION "\n");
+	//printf("**CFLAGS:** %s\n", "??");
+	printf("\n### Extensions:\n\n");
+	printf("* Name Pixmap: %s\n", ps->has_name_pixmap ? "Yes" : "No");
+	printf("* Shape: %s\n", ps->shape_exists ? "Yes" : "No");
+	printf("* XRandR: %s\n", ps->randr_exists ? "Yes" : "No");
+	printf("* Present: %s\n", ps->present_exists ? "Present" : "Not Present");
+	printf("\n### Misc:\n\n");
+	printf("* Use Overlay: %s\n", ps->overlay != XCB_NONE ? "Yes" : "No");
+#ifdef __FAST_MATH__
+	printf("* Fast Math: Yes\n");
+#endif
+}
+
+// vim: set noet sw=8 ts=8 :

src/diagnostic.h

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright (c) 2018 Yuxuan Shui <yshuiv7@gmail.com>
+
+#pragma once
+
+typedef struct session session_t;
+
+void print_diagnostics(session_t *);

src/meson.build

@@ -1,14 +1,19 @@
-deps = [ cc.find_library('m'), cc.find_library('ev') ]
+deps = [
+	cc.find_library('m'),
+	cc.find_library('ev'),
+	dependency('xcb', version: '>=1.9.2')
+]
 
 cflags = [ ]
 
-srcs = ['compton.c', 'win.c', 'c2.c', 'x.c', 'config.c']
+srcs = ['compton.c', 'win.c', 'c2.c', 'x.c', 'config.c', 'diagnostic.c']
 
 required_package = [
 	'x11', 'x11-xcb', 'xcb-renderutil',
 	'xcb-render', 'xcb-damage', 'xcb-randr',
 	'xcb-composite', 'xcb-shape', 'xcb-image',
-	'xcb-xfixes', 'xext', 'pixman-1']
+	'xcb-xfixes', 'xcb-present', 'xext', 'pixman-1'
+]
 
 foreach i : required_package
 	deps += [dependency(i, required: true)]