libweston: add struct weston_drm_format

Add struct weston_drm_format, which contains a DRM format and a list of
modifiers. The patch also adds struct weston_drm_format_array and some
helper functions to handle these two new structs: init/fini, find
elements, add elements, etc.

This will be useful in the next commits in which we add support to
dmabuf-hints. It also allows a cleanup in the DRM-backend, where we
currently have a similar struct in drm_plane but with no helper
functions, so the code to handle it is scattered throughout the
functions and there is a lot of repetition.

This patch is based on previous work of Scott Anderson (@ascent).

Signed-off-by: Scott Anderson <scott.anderson@collabora.com>
Signed-off-by: Leandro Ribeiro <leandro.ribeiro@collabora.com>

libweston/drm-formats.c

@@ -0,0 +1,516 @@
+/*
+ * Copyright © 2021 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "config.h"
+
+#include <assert.h>
+
+#include <libweston/libweston.h>
+#include "libweston-internal.h"
+#include "shared/weston-drm-fourcc.h"
+
+/**
+ * Create and initialize a weston_drm_format_array
+ *
+ * @return The weston_drm_format_array, or NULL on failure
+ */
+WL_EXPORT struct weston_drm_format_array *
+weston_drm_format_array_create(void)
+{
+	struct weston_drm_format_array *formats;
+
+	formats = zalloc(sizeof(*formats));
+	if (!formats) {
+		weston_log("%s: out of memory\n", __func__);
+		return NULL;
+	}
+
+	weston_drm_format_array_init(formats);
+
+	return formats;
+}
+
+/**
+ * Initialize a weston_drm_format_array
+ *
+ * @param formats The weston_drm_format_array to initialize
+ */
+WL_EXPORT void
+weston_drm_format_array_init(struct weston_drm_format_array *formats)
+{
+	wl_array_init(&formats->arr);
+}
+
+/**
+ * Fini and destroy a weston_drm_format_array
+ *
+ * @param formats The weston_drm_format_array to destroy
+ */
+WL_EXPORT void
+weston_drm_format_array_destroy(struct weston_drm_format_array *formats)
+{
+	weston_drm_format_array_fini(formats);
+	free(formats);
+}
+
+/**
+ * Finish a weston_drm_format_array
+ *
+ * It releases the modifiers set for each format and then the
+ * formats array itself.
+ *
+ * @param formats The weston_drm_format_array to finish
+ */
+WL_EXPORT void
+weston_drm_format_array_fini(struct weston_drm_format_array *formats)
+{
+	struct weston_drm_format *fmt;
+
+	wl_array_for_each(fmt, &formats->arr)
+		wl_array_release(&fmt->modifiers);
+
+	wl_array_release(&formats->arr);
+}
+
+static int
+add_format_and_modifiers(struct weston_drm_format_array *formats,
+			 uint32_t format, struct wl_array *modifiers)
+{
+	struct weston_drm_format *fmt;
+	int ret;
+
+	fmt = weston_drm_format_array_add_format(formats, format);
+	if (!fmt)
+		return -1;
+
+	ret = wl_array_copy(&fmt->modifiers, modifiers);
+	if (ret < 0) {
+		weston_log("%s: out of memory\n", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * Replace the content of a weston_drm_format_array
+ *
+ * Frees the content of the array and then perform a deep copy using
+ * source_formats. It duplicates the array of formats and for each format it
+ * duplicates the modifiers set as well.
+ *
+ * @param formats The weston_drm_format_array that gets its content replaced
+ * @param source_formats The weston_drm_format_array to copy
+ * @return 0 on success, -1 on failure
+ */
+WL_EXPORT int
+weston_drm_format_array_replace(struct weston_drm_format_array *formats,
+				const struct weston_drm_format_array *source_formats)
+{
+	struct weston_drm_format *source_fmt;
+	int ret;
+
+	weston_drm_format_array_fini(formats);
+	weston_drm_format_array_init(formats);
+
+	wl_array_for_each(source_fmt, &source_formats->arr) {
+		ret = add_format_and_modifiers(formats, source_fmt->format,
+					       &source_fmt->modifiers);
+		if (ret < 0)
+			return -1;
+	}
+
+	return 0;
+}
+
+/**
+ * Add format to weston_drm_format_array
+ *
+ * Adding repeated formats is considered an error.
+ *
+ * @param formats The weston_drm_format_array that receives the format
+ * @param format The format to add to the array
+ * @return The weston_drm_format, or NULL on failure
+ */
+WL_EXPORT struct weston_drm_format *
+weston_drm_format_array_add_format(struct weston_drm_format_array *formats,
+				   uint32_t format)
+{
+	struct weston_drm_format *fmt;
+
+	/* We should not try to add repeated formats to an array. */
+	assert(!weston_drm_format_array_find_format(formats, format));
+
+	fmt = wl_array_add(&formats->arr, sizeof(*fmt));
+	if (!fmt) {
+		weston_log("%s: out of memory\n", __func__);
+		return NULL;
+	}
+
+	fmt->format = format;
+	wl_array_init(&fmt->modifiers);
+
+	return fmt;
+}
+
+/**
+ * Remove latest format added to a weston_drm_format_array
+ *
+ * Calling this function for an empty array is an error, at least one element
+ * must be in the array.
+ *
+ * @param formats The weston_drm_format_array from which the format is removed
+ */
+WL_EXPORT void
+weston_drm_format_array_remove_latest_format(struct weston_drm_format_array *formats)
+{
+	struct wl_array *array = &formats->arr;
+	struct weston_drm_format *fmt;
+
+	assert(array->size >= sizeof(*fmt));
+
+	array->size -= sizeof(*fmt);
+
+	fmt = array->data + array->size;
+	wl_array_release(&fmt->modifiers);
+}
+
+/**
+ * Find format in a weston_drm_format_array
+ *
+ * @param formats The weston_drm_format_array where to look for the format
+ * @param format The format to look for
+ * @return The weston_drm_format if format was found, or NULL otherwise
+ */
+WL_EXPORT struct weston_drm_format *
+weston_drm_format_array_find_format(const struct weston_drm_format_array *formats,
+				    uint32_t format)
+{
+	struct weston_drm_format *fmt;
+
+	wl_array_for_each(fmt, &formats->arr)
+		if (fmt->format == format)
+			return fmt;
+
+	return NULL;
+}
+
+/**
+ * Compare the content of two weston_drm_format_array
+ *
+ * @param formats_A One of the weston_drm_format_array to compare
+ * @param formats_B The other weston_drm_format_array to compare
+ * @return True if both sets are equivalent, false otherwise
+ */
+WL_EXPORT bool
+weston_drm_format_array_equal(const struct weston_drm_format_array *formats_A,
+			      const struct weston_drm_format_array *formats_B)
+{
+	struct weston_drm_format *fmt_A, *fmt_B;
+	const uint64_t *modifiers_A;
+	unsigned num_modifiers_A, num_modifiers_B;
+	unsigned int i;
+
+	if (formats_A->arr.size != formats_B->arr.size)
+		return false;
+
+	wl_array_for_each(fmt_A, &formats_A->arr) {
+		fmt_B = weston_drm_format_array_find_format(formats_B,
+							    fmt_A->format);
+		if (!fmt_B)
+			return false;
+
+		modifiers_A = weston_drm_format_get_modifiers(fmt_A, &num_modifiers_A);
+		weston_drm_format_get_modifiers(fmt_B, &num_modifiers_B);
+		if (num_modifiers_A != num_modifiers_B)
+			return false;
+		for (i = 0; i < num_modifiers_A; i++)
+			if (!weston_drm_format_has_modifier(fmt_B, modifiers_A[i]))
+				return false;
+	}
+
+	return true;
+}
+
+/**
+ * Joins two weston_drm_format_array, keeping the result in A
+ *
+ * @param formats_A The weston_drm_format_array that receives the formats from B
+ * @param formats_B The weston_drm_format_array whose formats are added to A
+ * @return 0 on success, -1 on failure
+ */
+WL_EXPORT int
+weston_drm_format_array_join(struct weston_drm_format_array *formats_A,
+			     const struct weston_drm_format_array *formats_B)
+{
+	struct weston_drm_format *fmt_A, *fmt_B;
+	const uint64_t *modifiers;
+	unsigned int num_modifiers;
+	unsigned int i;
+	int ret;
+
+	wl_array_for_each(fmt_B, &formats_B->arr) {
+		fmt_A = weston_drm_format_array_find_format(formats_A,
+							    fmt_B->format);
+		if (!fmt_A) {
+			fmt_A = weston_drm_format_array_add_format(formats_A,
+								   fmt_B->format);
+			if (!fmt_A)
+				return -1;
+		}
+
+		modifiers = weston_drm_format_get_modifiers(fmt_B, &num_modifiers);
+		for (i = 0; i < num_modifiers; i++) {
+			if (weston_drm_format_has_modifier(fmt_A, modifiers[i]))
+				continue;
+			ret = weston_drm_format_add_modifier(fmt_A, modifiers[i]);
+			if (ret < 0)
+				return -1;
+		}
+	}
+
+	return 0;
+}
+
+static int
+modifiers_intersect(const struct weston_drm_format *fmt_A,
+		    const struct weston_drm_format *fmt_B,
+		    struct wl_array *modifiers_result)
+{
+	const uint64_t *modifiers;
+	unsigned int num_modifiers;
+	uint64_t *mod;
+	unsigned int i;
+
+	modifiers = weston_drm_format_get_modifiers(fmt_A, &num_modifiers);
+	for (i = 0; i < num_modifiers; i++) {
+		if (!weston_drm_format_has_modifier(fmt_B, modifiers[i]))
+			continue;
+		mod = wl_array_add(modifiers_result, sizeof(modifiers[i]));
+		if (!mod) {
+			weston_log("%s: out of memory\n", __func__);
+			return -1;
+		}
+		*mod = modifiers[i];
+	}
+
+	return 0;
+}
+
+/**
+ * Compute the intersection between two DRM-format arrays
+ *
+ * Callers are responsible for destroying the returned array.
+ *
+ * @param formats_A One of the weston_drm_format_array
+ * @param formats_B The other weston_drm_format_array
+ * @return Array with formats and modifiers that are present
+ * on both A and B, or NULL on failure
+ */
+WL_EXPORT struct weston_drm_format_array *
+weston_drm_format_array_intersect(const struct weston_drm_format_array *formats_A,
+				  const struct weston_drm_format_array *formats_B)
+{
+	struct weston_drm_format_array *formats_result;
+	struct weston_drm_format *fmt_result, *fmt_A, *fmt_B;
+	int ret;
+
+	formats_result = weston_drm_format_array_create();
+	if (!formats_result)
+		return NULL;
+
+	wl_array_for_each(fmt_A, &formats_A->arr) {
+		fmt_B = weston_drm_format_array_find_format(formats_B,
+							    fmt_A->format);
+		if (!fmt_B)
+			continue;
+
+		fmt_result = weston_drm_format_array_add_format(formats_result,
+								fmt_A->format);
+		if (!fmt_result)
+			goto err;
+
+		ret = modifiers_intersect(fmt_A, fmt_B, &fmt_result->modifiers);
+		if (ret < 0)
+			goto err;
+
+		if (fmt_result->modifiers.size == 0)
+			weston_drm_format_array_remove_latest_format(formats_result);
+	}
+
+	return formats_result;
+
+err:
+	weston_drm_format_array_destroy(formats_result);
+	return NULL;
+}
+
+static int
+modifiers_subtract(const struct weston_drm_format *fmt_A,
+		   const struct weston_drm_format *fmt_B,
+		   struct wl_array *modifiers_result)
+{
+	const uint64_t *modifiers;
+	unsigned int num_modifiers;
+	uint64_t *mod;
+	unsigned int i;
+
+	modifiers = weston_drm_format_get_modifiers(fmt_A, &num_modifiers);
+	for (i = 0; i < num_modifiers; i++) {
+		if (weston_drm_format_has_modifier(fmt_B, modifiers[i]))
+			continue;
+		mod = wl_array_add(modifiers_result, sizeof(modifiers[i]));
+		if (!mod) {
+			weston_log("%s: out of memory\n", __func__);
+			return -1;
+		}
+		*mod = modifiers[i];
+	}
+
+	return 0;
+}
+
+/**
+ * Compute the subtraction between two DRM-format arrays, keeping the result in A
+ *
+ * @param formats_A The minuend weston_drm_format_array
+ * @param formats_B The subtrahend weston_drm_format_array
+ * @return 0 on success, -1 on failure
+ */
+WL_EXPORT int
+weston_drm_format_array_subtract(struct weston_drm_format_array *formats_A,
+				 const struct weston_drm_format_array *formats_B)
+{
+	struct weston_drm_format_array *formats_result;
+	struct weston_drm_format *fmt_result, *fmt_A, *fmt_B;
+	int ret;
+
+	formats_result = weston_drm_format_array_create();
+	if (!formats_result)
+		return -1;
+
+	wl_array_for_each(fmt_A, &formats_A->arr) {
+		fmt_B = weston_drm_format_array_find_format(formats_B,
+							    fmt_A->format);
+		if (!fmt_B) {
+			ret = add_format_and_modifiers(formats_result, fmt_A->format,
+						       &fmt_A->modifiers);
+			if (ret < 0)
+				goto err;
+
+			continue;
+		}
+
+		fmt_result = weston_drm_format_array_add_format(formats_result,
+								fmt_A->format);
+		if (!fmt_result)
+			goto err;
+
+		ret = modifiers_subtract(fmt_A, fmt_B, &fmt_result->modifiers);
+		if (ret < 0)
+			goto err;
+
+		if (fmt_result->modifiers.size == 0)
+			weston_drm_format_array_remove_latest_format(formats_result);
+	}
+
+	ret = weston_drm_format_array_replace(formats_A, formats_result);
+	if (ret < 0)
+		goto err;
+
+	return 0;
+
+err:
+	weston_drm_format_array_destroy(formats_result);
+	return -1;
+}
+
+/**
+ * Add modifier to modifier set of a weston_drm_format.
+ *
+ * Adding repeated modifiers is considered an error.
+ *
+ * @param format The weston_drm_format that owns the modifier set to which
+ * the modifier should be added
+ * @param modifier The modifier to add
+ * @return 0 on success, -1 on failure
+ */
+WL_EXPORT int
+weston_drm_format_add_modifier(struct weston_drm_format *format,
+			       uint64_t modifier)
+{
+	uint64_t *mod;
+
+	/* We should not try to add repeated modifiers to a set. */
+	assert(!weston_drm_format_has_modifier(format, modifier));
+
+	mod = wl_array_add(&format->modifiers, sizeof(*mod));
+	if (!mod) {
+		weston_log("%s: out of memory\n", __func__);
+		return -1;
+	}
+	*mod = modifier;
+
+	return 0;
+}
+
+/**
+ * Check if modifier set of a weston_drm_format contains a certain modifier
+ *
+ * @param format The weston_drm_format that owns the modifier set where to
+ * look for the modifier
+ * @param modifier The modifier to look for
+ * @return True if modifier was found, false otherwise
+ */
+WL_EXPORT bool
+weston_drm_format_has_modifier(const struct weston_drm_format *format,
+			       uint64_t modifier)
+{
+	const uint64_t *modifiers;
+	unsigned int num_modifiers;
+	unsigned int i;
+
+	modifiers = weston_drm_format_get_modifiers(format, &num_modifiers);
+	for (i = 0; i < num_modifiers; i++)
+		if (modifiers[i] == modifier)
+			return true;
+
+	return false;
+}
+
+/**
+ * Get array of modifiers and modifiers count from a weston_drm_format
+ *
+ * @param format The weston_drm_format that contains the modifiers
+ * @param count_out Parameter that receives the modifiers count
+ * @return The array of modifiers
+ */
+WL_EXPORT const uint64_t *
+weston_drm_format_get_modifiers(const struct weston_drm_format *format,
+				unsigned int *count_out)
+{
+	*count_out = format->modifiers.size / sizeof(uint64_t);
+	return format->modifiers.data;
+}

libweston/libweston-internal.h

@@ -325,6 +325,72 @@ void
 weston_protected_surface_send_event(struct protected_surface *psurface,
 				    enum weston_hdcp_protection protection);
 
+/* weston_drm_format */
+
+struct weston_drm_format {
+	uint32_t format;
+	struct wl_array modifiers;
+};
+
+struct weston_drm_format_array {
+	struct wl_array arr;
+};
+
+struct weston_drm_format_array *
+weston_drm_format_array_create(void);
+
+void
+weston_drm_format_array_init(struct weston_drm_format_array *formats);
+
+void
+weston_drm_format_array_destroy(struct weston_drm_format_array *formats);
+
+void
+weston_drm_format_array_fini(struct weston_drm_format_array *formats);
+
+int
+weston_drm_format_array_replace(struct weston_drm_format_array *formats,
+				const struct weston_drm_format_array *source_formats);
+
+struct weston_drm_format *
+weston_drm_format_array_add_format(struct weston_drm_format_array *formats,
+				   uint32_t format);
+
+void
+weston_drm_format_array_remove_latest_format(struct weston_drm_format_array *formats);
+
+struct weston_drm_format *
+weston_drm_format_array_find_format(const struct weston_drm_format_array *formats,
+				    uint32_t format);
+
+bool
+weston_drm_format_array_equal(const struct weston_drm_format_array *formats_A,
+			      const struct weston_drm_format_array *formats_B);
+
+int
+weston_drm_format_array_join(struct weston_drm_format_array *formats_A,
+			     const struct weston_drm_format_array *formats_B);
+
+struct weston_drm_format_array *
+weston_drm_format_array_intersect(const struct weston_drm_format_array *formats_A,
+				  const struct weston_drm_format_array *formats_B);
+
+int
+weston_drm_format_array_subtract(struct weston_drm_format_array *formats_A,
+				 const struct weston_drm_format_array *formats_B);
+
+int
+weston_drm_format_add_modifier(struct weston_drm_format *format,
+			       uint64_t modifier);
+
+bool
+weston_drm_format_has_modifier(const struct weston_drm_format *format,
+			       uint64_t modifier);
+
+const uint64_t *
+weston_drm_format_get_modifiers(const struct weston_drm_format *format,
+				unsigned int *count_out);
+
 /* others */
 int
 wl_data_device_manager_init(struct wl_display *display);

libweston/meson.build

@@ -15,6 +15,7 @@ srcs_libweston = [
 	'compositor.c',
 	'content-protection.c',
 	'data-device.c',
+	'drm-formats.c',
 	'input.c',
 	'linux-dmabuf.c',
 	'linux-explicit-synchronization.c',