Fixed broken files/code and other errors

1 files changed, 748 insertions, 0 deletions

diff --git a/src/x.c b/src/x.c
new file mode 100644
index 0000000..c146f48
--- /dev/null
+++ b/src/x.c
@@ -0,0 +1,748 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright (c) 2018 Yuxuan Shui <[email protected]>
+#include <stdalign.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include <X11/Xutil.h>
+#include <pixman.h>
+#include <xcb/composite.h>
+#include <xcb/damage.h>
+#include <xcb/glx.h>
+#include <xcb/render.h>
+#include <xcb/sync.h>
+#include <xcb/xcb.h>
+#include <xcb/xcb_renderutil.h>
+#include <xcb/xfixes.h>
+
+#include "atom.h"
+#ifdef CONFIG_OPENGL
+#include "backend/gl/glx.h"
+#endif
+#include "common.h"
+#include "compiler.h"
+#include "kernel.h"
+#include "log.h"
+#include "region.h"
+#include "utils.h"
+#include "x.h"
+
+/**
+ * Get a specific attribute of a window.
+ *
+ * Returns a blank structure if the returned type and format does not
+ * match the requested type and format.
+ *
+ * @param ps current session
+ * @param w window
+ * @param atom atom of attribute to fetch
+ * @param length length to read
+ * @param rtype atom of the requested type
+ * @param rformat requested format
+ * @return a <code>winprop_t</code> structure containing the attribute
+ *    and number of items. A blank one on failure.
+ */
+winprop_t x_get_prop_with_offset(xcb_connection_t *c, xcb_window_t w, xcb_atom_t atom,
+                                 int offset, int length, xcb_atom_t rtype, int rformat) {
+	xcb_get_property_reply_t *r = xcb_get_property_reply(
+	    c,
+	    xcb_get_property(c, 0, w, atom, rtype, to_u32_checked(offset),
+	                     to_u32_checked(length)),
+	    NULL);
+
+	if (r && xcb_get_property_value_length(r) &&
+	    (rtype == XCB_GET_PROPERTY_TYPE_ANY || r->type == rtype) &&
+	    (!rformat || r->format == rformat) &&
+	    (r->format == 8 || r->format == 16 || r->format == 32)) {
+		auto len = xcb_get_property_value_length(r);
+		return (winprop_t){
+		    .ptr = xcb_get_property_value(r),
+		    .nitems = (ulong)(len / (r->format / 8)),
+		    .type = r->type,
+		    .format = r->format,
+		    .r = r,
+		};
+	}
+
+	free(r);
+	return (winprop_t){
+	    .ptr = NULL, .nitems = 0, .type = XCB_GET_PROPERTY_TYPE_ANY, .format = 0};
+}
+
+/// Get the type, format and size in bytes of a window's specific attribute.
+winprop_info_t x_get_prop_info(xcb_connection_t *c, xcb_window_t w, xcb_atom_t atom) {
+	xcb_generic_error_t *e = NULL;
+	auto r = xcb_get_property_reply(
+	    c, xcb_get_property(c, 0, w, atom, XCB_ATOM_ANY, 0, 0), &e);
+	if (!r) {
+		log_debug_x_error(e, "Failed to get property info for window %#010x", w);
+		free(e);
+		return (winprop_info_t){
+		    .type = XCB_GET_PROPERTY_TYPE_ANY, .format = 0, .length = 0};
+	}
+
+	winprop_info_t winprop_info = {
+	    .type = r->type, .format = r->format, .length = r->bytes_after};
+	free(r);
+
+	return winprop_info;
+}
+
+/**
+ * Get the value of a type-<code>xcb_window_t</code> property of a window.
+ *
+ * @return the value if successful, 0 otherwise
+ */
+xcb_window_t wid_get_prop_window(xcb_connection_t *c, xcb_window_t wid, xcb_atom_t aprop) {
+	// Get the attribute
+	xcb_window_t p = XCB_NONE;
+	winprop_t prop = x_get_prop(c, wid, aprop, 1L, XCB_ATOM_WINDOW, 32);
+
+	// Return it
+	if (prop.nitems) {
+		p = (xcb_window_t)*prop.p32;
+	}
+
+	free_winprop(&prop);
+
+	return p;
+}
+
+/**
+ * Get the value of a text property of a window.
+ */
+bool wid_get_text_prop(session_t *ps, xcb_window_t wid, xcb_atom_t prop, char ***pstrlst,
+                       int *pnstr) {
+	assert(ps->server_grabbed);
+	auto prop_info = x_get_prop_info(ps->c, wid, prop);
+	auto type = prop_info.type;
+	auto format = prop_info.format;
+	auto length = prop_info.length;
+
+	if (type == XCB_ATOM_NONE) {
+		return false;
+	}
+
+	if (type != XCB_ATOM_STRING && type != ps->atoms->aUTF8_STRING &&
+	    type != ps->atoms->aC_STRING) {
+		log_warn("Text property %d of window %#010x has unsupported type: %d",
+		         prop, wid, type);
+		return false;
+	}
+
+	if (format != 8) {
+		log_warn("Text property %d of window %#010x has unexpected format: %d",
+		         prop, wid, format);
+		return false;
+	}
+
+	xcb_generic_error_t *e = NULL;
+	auto word_count = (length + 4 - 1) / 4;
+	auto r = xcb_get_property_reply(
+	    ps->c, xcb_get_property(ps->c, 0, wid, prop, type, 0, word_count), &e);
+	if (!r) {
+		log_debug_x_error(e, "Failed to get window property for %#010x", wid);
+		free(e);
+		return false;
+	}
+
+	assert(length == (uint32_t)xcb_get_property_value_length(r));
+
+	void *data = xcb_get_property_value(r);
+	unsigned int nstr = 0;
+	uint32_t current_offset = 0;
+	while (current_offset < length) {
+		current_offset +=
+		    (uint32_t)strnlen(data + current_offset, length - current_offset) + 1;
+		nstr += 1;
+	}
+
+	if (nstr == 0) {
+		// The property is set to an empty string, in that case, we return one
+		// string
+		char **strlst = malloc(sizeof(char *));
+		strlst[0] = "";
+		*pnstr = 1;
+		*pstrlst = strlst;
+		free(r);
+		return true;
+	}
+
+	// Allocate the pointers and the strings together
+	void *buf = NULL;
+	if (posix_memalign(&buf, alignof(char *), length + sizeof(char *) * nstr + 1) != 0) {
+		abort();
+	}
+
+	char *strlst = buf + sizeof(char *) * nstr;
+	memcpy(strlst, xcb_get_property_value(r), length);
+	strlst[length] = '\0';        // X strings aren't guaranteed to be null terminated
+
+	char **ret = buf;
+	current_offset = 0;
+	nstr = 0;
+	while (current_offset < length) {
+		ret[nstr] = strlst + current_offset;
+		current_offset += (uint32_t)strlen(strlst + current_offset) + 1;
+		nstr += 1;
+	}
+
+	*pnstr = to_int_checked(nstr);
+	*pstrlst = ret;
+	free(r);
+	return true;
+}
+
+// A cache of pict formats. We assume they don't change during the lifetime
+// of this program
+static thread_local xcb_render_query_pict_formats_reply_t *g_pictfmts = NULL;
+
+static inline void x_get_server_pictfmts(xcb_connection_t *c) {
+	if (g_pictfmts) {
+		return;
+	}
+	xcb_generic_error_t *e = NULL;
+	// Get window picture format
+	g_pictfmts =
+	    xcb_render_query_pict_formats_reply(c, xcb_render_query_pict_formats(c), &e);
+	if (e || !g_pictfmts) {
+		log_fatal("failed to get pict formats\n");
+		abort();
+	}
+}
+
+const xcb_render_pictforminfo_t *
+x_get_pictform_for_visual(xcb_connection_t *c, xcb_visualid_t visual) {
+	x_get_server_pictfmts(c);
+
+	xcb_render_pictvisual_t *pv = xcb_render_util_find_visual_format(g_pictfmts, visual);
+	for (xcb_render_pictforminfo_iterator_t i =
+	         xcb_render_query_pict_formats_formats_iterator(g_pictfmts);
+	     i.rem; xcb_render_pictforminfo_next(&i)) {
+		if (i.data->id == pv->format) {
+			return i.data;
+		}
+	}
+	return NULL;
+}
+
+static xcb_visualid_t attr_pure x_get_visual_for_pictfmt(xcb_render_query_pict_formats_reply_t *r,
+                                                         xcb_render_pictformat_t fmt) {
+	for (auto screen = xcb_render_query_pict_formats_screens_iterator(r); screen.rem;
+	     xcb_render_pictscreen_next(&screen)) {
+		for (auto depth = xcb_render_pictscreen_depths_iterator(screen.data);
+		     depth.rem; xcb_render_pictdepth_next(&depth)) {
+			for (auto pv = xcb_render_pictdepth_visuals_iterator(depth.data);
+			     pv.rem; xcb_render_pictvisual_next(&pv)) {
+				if (pv.data->format == fmt) {
+					return pv.data->visual;
+				}
+			}
+		}
+	}
+	return XCB_NONE;
+}
+
+xcb_visualid_t x_get_visual_for_standard(xcb_connection_t *c, xcb_pict_standard_t std) {
+	x_get_server_pictfmts(c);
+
+	auto pictfmt = xcb_render_util_find_standard_format(g_pictfmts, std);
+
+	return x_get_visual_for_pictfmt(g_pictfmts, pictfmt->id);
+}
+
+xcb_render_pictformat_t
+x_get_pictfmt_for_standard(xcb_connection_t *c, xcb_pict_standard_t std) {
+	x_get_server_pictfmts(c);
+
+	auto pictfmt = xcb_render_util_find_standard_format(g_pictfmts, std);
+
+	return pictfmt->id;
+}
+
+int x_get_visual_depth(xcb_connection_t *c, xcb_visualid_t visual) {
+	auto setup = xcb_get_setup(c);
+	for (auto screen = xcb_setup_roots_iterator(setup); screen.rem;
+	     xcb_screen_next(&screen)) {
+		for (auto depth = xcb_screen_allowed_depths_iterator(screen.data);
+		     depth.rem; xcb_depth_next(&depth)) {
+			const int len = xcb_depth_visuals_length(depth.data);
+			const xcb_visualtype_t *visuals = xcb_depth_visuals(depth.data);
+			for (int i = 0; i < len; i++) {
+				if (visual == visuals[i].visual_id) {
+					return depth.data->depth;
+				}
+			}
+		}
+	}
+	return -1;
+}
+
+xcb_render_picture_t
+x_create_picture_with_pictfmt_and_pixmap(xcb_connection_t *c,
+                                         const xcb_render_pictforminfo_t *pictfmt,
+                                         xcb_pixmap_t pixmap, uint32_t valuemask,
+                                         const xcb_render_create_picture_value_list_t *attr) {
+	void *buf = NULL;
+	if (attr) {
+		xcb_render_create_picture_value_list_serialize(&buf, valuemask, attr);
+		if (!buf) {
+			log_error("failed to serialize picture attributes");
+			return XCB_NONE;
+		}
+	}
+
+	xcb_render_picture_t tmp_picture = x_new_id(c);
+	xcb_generic_error_t *e =
+	    xcb_request_check(c, xcb_render_create_picture_checked(
+	                             c, tmp_picture, pixmap, pictfmt->id, valuemask, buf));
+	free(buf);
+	if (e) {
+		log_error_x_error(e, "failed to create picture");
+		return XCB_NONE;
+	}
+	return tmp_picture;
+}
+
+xcb_render_picture_t
+x_create_picture_with_visual_and_pixmap(xcb_connection_t *c, xcb_visualid_t visual,
+                                        xcb_pixmap_t pixmap, uint32_t valuemask,
+                                        const xcb_render_create_picture_value_list_t *attr) {
+	const xcb_render_pictforminfo_t *pictfmt = x_get_pictform_for_visual(c, visual);
+	return x_create_picture_with_pictfmt_and_pixmap(c, pictfmt, pixmap, valuemask, attr);
+}
+
+xcb_render_picture_t
+x_create_picture_with_standard_and_pixmap(xcb_connection_t *c, xcb_pict_standard_t standard,
+                                          xcb_pixmap_t pixmap, uint32_t valuemask,
+                                          const xcb_render_create_picture_value_list_t *attr) {
+	x_get_server_pictfmts(c);
+
+	auto pictfmt = xcb_render_util_find_standard_format(g_pictfmts, standard);
+	assert(pictfmt);
+	return x_create_picture_with_pictfmt_and_pixmap(c, pictfmt, pixmap, valuemask, attr);
+}
+
+xcb_render_picture_t
+x_create_picture_with_standard(xcb_connection_t *c, xcb_drawable_t d, int w, int h,
+                               xcb_pict_standard_t standard, uint32_t valuemask,
+                               const xcb_render_create_picture_value_list_t *attr) {
+	x_get_server_pictfmts(c);
+
+	auto pictfmt = xcb_render_util_find_standard_format(g_pictfmts, standard);
+	assert(pictfmt);
+	return x_create_picture_with_pictfmt(c, d, w, h, pictfmt, valuemask, attr);
+}
+
+/**
+ * Create an picture.
+ */
+xcb_render_picture_t
+x_create_picture_with_pictfmt(xcb_connection_t *c, xcb_drawable_t d, int w, int h,
+                              const xcb_render_pictforminfo_t *pictfmt, uint32_t valuemask,
+                              const xcb_render_create_picture_value_list_t *attr) {
+	uint8_t depth = pictfmt->depth;
+
+	xcb_pixmap_t tmp_pixmap = x_create_pixmap(c, depth, d, w, h);
+	if (!tmp_pixmap) {
+		return XCB_NONE;
+	}
+
+	xcb_render_picture_t picture = x_create_picture_with_pictfmt_and_pixmap(
+	    c, pictfmt, tmp_pixmap, valuemask, attr);
+
+	xcb_free_pixmap(c, tmp_pixmap);
+
+	return picture;
+}
+
+xcb_render_picture_t
+x_create_picture_with_visual(xcb_connection_t *c, xcb_drawable_t d, int w, int h,
+                             xcb_visualid_t visual, uint32_t valuemask,
+                             const xcb_render_create_picture_value_list_t *attr) {
+	auto pictfmt = x_get_pictform_for_visual(c, visual);
+	return x_create_picture_with_pictfmt(c, d, w, h, pictfmt, valuemask, attr);
+}
+
+bool x_fetch_region(xcb_connection_t *c, xcb_xfixes_region_t r, pixman_region32_t *res) {
+	xcb_generic_error_t *e = NULL;
+	xcb_xfixes_fetch_region_reply_t *xr =
+	    xcb_xfixes_fetch_region_reply(c, xcb_xfixes_fetch_region(c, r), &e);
+	if (!xr) {
+		log_error_x_error(e, "Failed to fetch rectangles");
+		return false;
+	}
+
+	int nrect = xcb_xfixes_fetch_region_rectangles_length(xr);
+	auto b = ccalloc(nrect, pixman_box32_t);
+	xcb_rectangle_t *xrect = xcb_xfixes_fetch_region_rectangles(xr);
+	for (int i = 0; i < nrect; i++) {
+		b[i] = (pixman_box32_t){.x1 = xrect[i].x,
+		                        .y1 = xrect[i].y,
+		                        .x2 = xrect[i].x + xrect[i].width,
+		                        .y2 = xrect[i].y + xrect[i].height};
+	}
+	bool ret = pixman_region32_init_rects(res, b, nrect);
+	free(b);
+	free(xr);
+	return ret;
+}
+
+void x_set_picture_clip_region(xcb_connection_t *c, xcb_render_picture_t pict,
+                               int16_t clip_x_origin, int16_t clip_y_origin,
+                               const region_t *reg) {
+	int nrects;
+	const rect_t *rects = pixman_region32_rectangles((region_t *)reg, &nrects);
+	auto xrects = ccalloc(nrects, xcb_rectangle_t);
+	for (int i = 0; i < nrects; i++) {
+		xrects[i] = (xcb_rectangle_t){
+		    .x = to_i16_checked(rects[i].x1),
+		    .y = to_i16_checked(rects[i].y1),
+		    .width = to_u16_checked(rects[i].x2 - rects[i].x1),
+		    .height = to_u16_checked(rects[i].y2 - rects[i].y1),
+		};
+	}
+
+	xcb_generic_error_t *e = xcb_request_check(
+	    c, xcb_render_set_picture_clip_rectangles_checked(
+	           c, pict, clip_x_origin, clip_y_origin, to_u32_checked(nrects), xrects));
+	if (e) {
+		log_error_x_error(e, "Failed to set clip region");
+		free(e);
+	}
+	free(xrects);
+}
+
+void x_clear_picture_clip_region(xcb_connection_t *c, xcb_render_picture_t pict) {
+	xcb_render_change_picture_value_list_t v = {.clipmask = XCB_NONE};
+	xcb_generic_error_t *e = xcb_request_check(
+	    c, xcb_render_change_picture(c, pict, XCB_RENDER_CP_CLIP_MASK, &v));
+	if (e) {
+		log_error_x_error(e, "failed to clear clip region");
+		free(e);
+	}
+}
+
+enum {
+	XSyncBadCounter = 0,
+	XSyncBadAlarm = 1,
+	XSyncBadFence = 2,
+};
+
+/**
+ * Convert a X11 error to string
+ *
+ * @return a pointer to a string. this pointer shouldn NOT be freed, same buffer is used
+ *         for multiple calls to this function,
+ */
+static const char *
+_x_strerror(unsigned long serial, uint8_t major, uint16_t minor, uint8_t error_code) {
+	session_t *const ps = ps_g;
+
+	int o = 0;
+	const char *name = "Unknown";
+
+#define CASESTRRET(s)                                                                    \
+	case s:                                                                          \
+		name = #s;                                                               \
+		break
+
+#define CASESTRRET2(s)                                                                   \
+	case XCB_##s: name = #s; break
+
+	// TODO(yshui) separate error code out from session_t
+	o = error_code - ps->xfixes_error;
+	switch (o) { CASESTRRET2(XFIXES_BAD_REGION); }
+
+	o = error_code - ps->damage_error;
+	switch (o) { CASESTRRET2(DAMAGE_BAD_DAMAGE); }
+
+	o = error_code - ps->render_error;
+	switch (o) {
+		CASESTRRET2(RENDER_PICT_FORMAT);
+		CASESTRRET2(RENDER_PICTURE);
+		CASESTRRET2(RENDER_PICT_OP);
+		CASESTRRET2(RENDER_GLYPH_SET);
+		CASESTRRET2(RENDER_GLYPH);
+	}
+
+	if (ps->glx_exists) {
+		o = error_code - ps->glx_error;
+		switch (o) {
+			CASESTRRET2(GLX_BAD_CONTEXT);
+			CASESTRRET2(GLX_BAD_CONTEXT_STATE);
+			CASESTRRET2(GLX_BAD_DRAWABLE);
+			CASESTRRET2(GLX_BAD_PIXMAP);
+			CASESTRRET2(GLX_BAD_CONTEXT_TAG);
+			CASESTRRET2(GLX_BAD_CURRENT_WINDOW);
+			CASESTRRET2(GLX_BAD_RENDER_REQUEST);
+			CASESTRRET2(GLX_BAD_LARGE_REQUEST);
+			CASESTRRET2(GLX_UNSUPPORTED_PRIVATE_REQUEST);
+			CASESTRRET2(GLX_BAD_FB_CONFIG);
+			CASESTRRET2(GLX_BAD_PBUFFER);
+			CASESTRRET2(GLX_BAD_CURRENT_DRAWABLE);
+			CASESTRRET2(GLX_BAD_WINDOW);
+			CASESTRRET2(GLX_GLX_BAD_PROFILE_ARB);
+		}
+	}
+
+	if (ps->xsync_exists) {
+		o = error_code - ps->xsync_error;
+		switch (o) {
+			CASESTRRET(XSyncBadCounter);
+			CASESTRRET(XSyncBadAlarm);
+			CASESTRRET(XSyncBadFence);
+		}
+	}
+
+	switch (error_code) {
+		CASESTRRET2(ACCESS);
+		CASESTRRET2(ALLOC);
+		CASESTRRET2(ATOM);
+		CASESTRRET2(COLORMAP);
+		CASESTRRET2(CURSOR);
+		CASESTRRET2(DRAWABLE);
+		CASESTRRET2(FONT);
+		CASESTRRET2(G_CONTEXT);
+		CASESTRRET2(ID_CHOICE);
+		CASESTRRET2(IMPLEMENTATION);
+		CASESTRRET2(LENGTH);
+		CASESTRRET2(MATCH);
+		CASESTRRET2(NAME);
+		CASESTRRET2(PIXMAP);
+		CASESTRRET2(REQUEST);
+		CASESTRRET2(VALUE);
+		CASESTRRET2(WINDOW);
+	}
+
+#undef CASESTRRET
+#undef CASESTRRET2
+
+	thread_local static char buffer[256];
+	snprintf(buffer, sizeof(buffer), "X error %d %s request %d minor %d serial %lu",
+	         error_code, name, major, minor, serial);
+	return buffer;
+}
+
+/**
+ * Log a X11 error
+ */
+void x_print_error(unsigned long serial, uint8_t major, uint16_t minor, uint8_t error_code) {
+	log_debug("%s", _x_strerror(serial, major, minor, error_code));
+}
+
+/*
+ * Convert a xcb_generic_error_t to a string that describes the error
+ *
+ * @return a pointer to a string. this pointer shouldn NOT be freed, same buffer is used
+ *         for multiple calls to this function,
+ */
+const char *x_strerror(xcb_generic_error_t *e) {
+	if (!e) {
+		return "No error";
+	}
+	return _x_strerror(e->full_sequence, e->major_code, e->minor_code, e->error_code);
+}
+
+/**
+ * Create a pixmap and check that creation succeeded.
+ */
+xcb_pixmap_t x_create_pixmap(xcb_connection_t *c, uint8_t depth, xcb_drawable_t drawable,
+                             int width, int height) {
+	xcb_pixmap_t pix = x_new_id(c);
+	xcb_void_cookie_t cookie = xcb_create_pixmap_checked(
+	    c, depth, pix, drawable, to_u16_checked(width), to_u16_checked(height));
+	xcb_generic_error_t *err = xcb_request_check(c, cookie);
+	if (err == NULL) {
+		return pix;
+	}
+
+	log_error_x_error(err, "Failed to create pixmap");
+	free(err);
+	return XCB_NONE;
+}
+
+/**
+ * Validate a pixmap.
+ *
+ * Detect whether the pixmap is valid with XGetGeometry. Well, maybe there
+ * are better ways.
+ */
+bool x_validate_pixmap(xcb_connection_t *c, xcb_pixmap_t pixmap) {
+	if (pixmap == XCB_NONE) {
+		return false;
+	}
+
+	auto r = xcb_get_geometry_reply(c, xcb_get_geometry(c, pixmap), NULL);
+	if (!r) {
+		return false;
+	}
+
+	bool ret = r->width && r->height;
+	free(r);
+	return ret;
+}
+/// Names of root window properties that could point to a pixmap of
+/// background.
+static const char *background_props_str[] = {
+    "_XROOTPMAP_ID",
+    "_XSETROOT_ID",
+    0,
+};
+
+xcb_pixmap_t
+x_get_root_back_pixmap(xcb_connection_t *c, xcb_window_t root, struct atom *atoms) {
+	xcb_pixmap_t pixmap = XCB_NONE;
+
+	// Get the values of background attributes
+	for (int p = 0; background_props_str[p]; p++) {
+		xcb_atom_t prop_atom = get_atom(atoms, background_props_str[p]);
+		winprop_t prop = x_get_prop(c, root, prop_atom, 1, XCB_ATOM_PIXMAP, 32);
+		if (prop.nitems) {
+			pixmap = (xcb_pixmap_t)*prop.p32;
+			free_winprop(&prop);
+			break;
+		}
+		free_winprop(&prop);
+	}
+
+	return pixmap;
+}
+
+bool x_is_root_back_pixmap_atom(struct atom *atoms, xcb_atom_t atom) {
+	for (int p = 0; background_props_str[p]; p++) {
+		xcb_atom_t prop_atom = get_atom(atoms, background_props_str[p]);
+		if (prop_atom == atom) {
+			return true;
+		}
+	}
+	return false;
+}
+
+/**
+ * Synchronizes a X Render drawable to ensure all pending painting requests
+ * are completed.
+ */
+bool x_fence_sync(xcb_connection_t *c, xcb_sync_fence_t f) {
+	// TODO(richardgv): If everybody just follows the rules stated in X Sync
+	// prototype, we need only one fence per screen, but let's stay a bit
+	// cautious right now
+
+	auto e = xcb_request_check(c, xcb_sync_trigger_fence_checked(c, f));
+	if (e) {
+		log_error_x_error(e, "Failed to trigger the fence");
+		goto err;
+	}
+
+	e = xcb_request_check(c, xcb_sync_await_fence_checked(c, 1, &f));
+	if (e) {
+		log_error_x_error(e, "Failed to await on a fence");
+		goto err;
+	}
+
+	e = xcb_request_check(c, xcb_sync_reset_fence_checked(c, f));
+	if (e) {
+		log_error_x_error(e, "Failed to reset the fence");
+		goto err;
+	}
+	return true;
+
+err:
+	free(e);
+	return false;
+}
+
+// xcb-render specific macros
+#define XFIXED_TO_DOUBLE(value) (((double)(value)) / 65536)
+#define DOUBLE_TO_XFIXED(value) ((xcb_render_fixed_t)(((double)(value)) * 65536))
+
+/**
+ * Convert a struct conv to a X picture convolution filter, normalizing the kernel
+ * in the process. Allow the caller to specify the element at the center of the kernel,
+ * for compatibility with legacy code.
+ *
+ * @param[in] kernel the convolution kernel
+ * @param[in] center the element to put at the center of the matrix
+ * @param[inout] ret pointer to an array of `size`, if `size` is too small, more space
+ *                   will be allocated, and `*ret` will be updated
+ * @param[inout] size size of the array pointed to by `ret`, in number of elements
+ * @return number of elements filled into `*ret`
+ */
+void x_create_convolution_kernel(const conv *kernel, double center,
+                                 struct x_convolution_kernel **ret) {
+	assert(ret);
+	if (!*ret || (*ret)->capacity < kernel->w * kernel->h + 2) {
+		free(*ret);
+		*ret =
+		    cvalloc(sizeof(struct x_convolution_kernel) +
+		            (size_t)(kernel->w * kernel->h + 2) * sizeof(xcb_render_fixed_t));
+		(*ret)->capacity = kernel->w * kernel->h + 2;
+	}
+
+	(*ret)->size = kernel->w * kernel->h + 2;
+
+	auto buf = (*ret)->kernel;
+	buf[0] = DOUBLE_TO_XFIXED(kernel->w);
+	buf[1] = DOUBLE_TO_XFIXED(kernel->h);
+
+	double sum = center;
+	for (int i = 0; i < kernel->w * kernel->h; i++) {
+		if (i == kernel->w * kernel->h / 2) {
+			continue;
+		}
+		sum += kernel->data[i];
+	}
+
+	// Note for floating points a / b != a * (1 / b), but this shouldn't have any real
+	// impact on the result
+	double factor = sum != 0 ? 1.0 / sum : 1;
+	for (int i = 0; i < kernel->w * kernel->h; i++) {
+		buf[i + 2] = DOUBLE_TO_XFIXED(kernel->data[i] * factor);
+	}
+
+	buf[kernel->h / 2 * kernel->w + kernel->w / 2 + 2] =
+	    DOUBLE_TO_XFIXED(center * factor);
+}
+
+/// Generate a search criteria for fbconfig from a X visual.
+/// Returns {-1, -1, -1, -1, -1, 0} on failure
+struct xvisual_info x_get_visual_info(xcb_connection_t *c, xcb_visualid_t visual) {
+	auto pictfmt = x_get_pictform_for_visual(c, visual);
+	auto depth = x_get_visual_depth(c, visual);
+	if (!pictfmt || depth == -1) {
+		log_error("Invalid visual %#03x", visual);
+		return (struct xvisual_info){-1, -1, -1, -1, -1, 0};
+	}
+	if (pictfmt->type != XCB_RENDER_PICT_TYPE_DIRECT) {
+		log_error("We cannot handle non-DirectColor visuals. Report an "
+		          "issue if you see this error message.");
+		return (struct xvisual_info){-1, -1, -1, -1, -1, 0};
+	}
+
+	int red_size = popcntul(pictfmt->direct.red_mask),
+	    blue_size = popcntul(pictfmt->direct.blue_mask),
+	    green_size = popcntul(pictfmt->direct.green_mask),
+	    alpha_size = popcntul(pictfmt->direct.alpha_mask);
+
+	return (struct xvisual_info){
+	    .red_size = red_size,
+	    .green_size = green_size,
+	    .blue_size = blue_size,
+	    .alpha_size = alpha_size,
+	    .visual_depth = depth,
+	    .visual = visual,
+	};
+}
+
+xcb_screen_t *x_screen_of_display(xcb_connection_t *c, int screen) {
+	xcb_screen_iterator_t iter;
+
+	iter = xcb_setup_roots_iterator(xcb_get_setup(c));
+	for (; iter.rem; --screen, xcb_screen_next(&iter)) {
+		if (screen == 0) {
+			return iter.data;
+		}
+	}
+
+	return NULL;
+}