render: introduce wlr_drm_format_set

This types adds a container for formats + modifiers.

A list that is of [format [modifier]] was chosen instead of
[format modifer] because that is how GBM accepts them.

Co-Authored-By: emersion <contact@emersion.fr>

include/wlr/render/drm_format_set.h

@@ -0,0 +1,27 @@
+#ifndef WLR_RENDER_DRM_FORMAT_SET_H
+#define WLR_RENDER_DRM_FORMAT_SET_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+struct wlr_drm_format {
+	uint32_t format;
+	size_t len, cap;
+	uint64_t modifiers[];
+};
+
+struct wlr_drm_format_set {
+	size_t len, cap;
+	struct wlr_drm_format **formats;
+};
+
+void wlr_drm_format_set_finish(struct wlr_drm_format_set *set);
+
+const struct wlr_drm_format *wlr_drm_format_set_get(
+	const struct wlr_drm_format_set *set, uint32_t format);
+
+bool wlr_drm_format_set_add(struct wlr_drm_format_set *set, uint32_t format,
+	uint64_t modifier);
+
+#endif

include/wlr/render/meson.build

@@ -1,9 +1,10 @@
 install_headers(
 	'dmabuf.h',
 	'egl.h',
+	'drm_format_set.h',
 	'gles2.h',
 	'interface.h',
 	'wlr_renderer.h',
 	'wlr_texture.h',
-	subdir: 'wlr/render'
+	subdir: 'wlr/render',
 )

render/drm_format_set.c

@@ -0,0 +1,105 @@
+#include <drm_fourcc.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wlr/render/drm_format_set.h>
+#include <wlr/util/log.h>
+
+void wlr_drm_format_set_finish(struct wlr_drm_format_set *set) {
+	for (size_t i = 0; i < set->len; ++i) {
+		free(set->formats[i]);
+	}
+	free(set->formats);
+
+	set->len = 0;
+	set->cap = 0;
+	set->formats = NULL;
+}
+
+static struct wlr_drm_format **format_set_get_ref(struct wlr_drm_format_set *set,
+		uint32_t format) {
+	for (size_t i = 0; i < set->len; ++i) {
+		if (set->formats[i]->format == format) {
+			return &set->formats[i];
+		}
+	}
+
+	return NULL;
+}
+
+const struct wlr_drm_format *wlr_drm_format_set_get(
+		const struct wlr_drm_format_set *set, uint32_t format) {
+	struct wlr_drm_format **ptr =
+		format_set_get_ref((struct wlr_drm_format_set *)set, format);
+	return ptr ? *ptr : NULL;
+}
+
+bool wlr_drm_format_set_add(struct wlr_drm_format_set *set, uint32_t format,
+		uint64_t modifier) {
+	struct wlr_drm_format **ptr = format_set_get_ref(set, format);
+
+	if (ptr) {
+		struct wlr_drm_format *fmt = *ptr;
+
+		if (modifier == DRM_FORMAT_MOD_INVALID) {
+			return true;
+		}
+
+		for (size_t i = 0; i < fmt->len; ++i) {
+			if (fmt->modifiers[i] == modifier) {
+				return true;
+			}
+		}
+
+		if (fmt->len == fmt->cap) {
+			size_t cap = fmt->cap ? fmt->cap * 2 : 4;
+
+			fmt = realloc(fmt, sizeof(*fmt) + sizeof(fmt->modifiers[0]) * cap);
+			if (!fmt) {
+				wlr_log_errno(WLR_ERROR, "Allocation failed");
+				return false;
+			}
+
+			fmt->cap = cap;
+			*ptr = fmt;
+		}
+
+		fmt->modifiers[fmt->len++] = modifier;
+		return true;
+	}
+
+	size_t cap = modifier != DRM_FORMAT_MOD_INVALID ? 4 : 0;
+
+	struct wlr_drm_format *fmt =
+		calloc(1, sizeof(*fmt) + sizeof(fmt->modifiers[0]) * cap);
+	if (!fmt) {
+		wlr_log_errno(WLR_ERROR, "Allocation failed");
+		return false;
+	}
+
+	fmt->format = format;
+	if (cap) {
+		fmt->cap = cap;
+		fmt->len = 1;
+		fmt->modifiers[0] = modifier;
+	}
+
+	if (set->len == set->cap) {
+		size_t new = set->cap ? set->cap * 2 : 4;
+
+		struct wlr_drm_format **tmp = realloc(set->formats,
+			sizeof(*fmt) + sizeof(fmt->modifiers[0]) * new);
+		if (!tmp) {
+			wlr_log_errno(WLR_ERROR, "Allocation failed");
+			free(fmt);
+			return false;
+		}
+
+		set->cap = new;
+		set->formats = tmp;
+	}
+
+	set->formats[set->len++] = fmt;
+	return true;
+}

render/meson.build

@@ -12,6 +12,7 @@ lib_wlr_render = static_library(
 	files(
 		'dmabuf.c',
 		'egl.c',
+		'drm_format_set.c',
 		'gles2/pixel_format.c',
 		'gles2/renderer.c',
 		'gles2/shaders.c',
@@ -27,7 +28,7 @@ lib_wlr_render = static_library(
 		drm.partial_dependency(compile_args: true), # <drm_fourcc.h>
 		glesv2,
 		pixman,
-		wayland_server
+		wayland_server,
 	],
 )