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#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <wlr/interfaces/wlr_buffer.h>
#include <wlr/util/log.h>
#include "types/wlr_buffer.h"
static const struct wlr_buffer_impl readonly_data_buffer_impl;
static struct wlr_readonly_data_buffer *readonly_data_buffer_from_buffer(
struct wlr_buffer *wlr_buffer) {
assert(wlr_buffer->impl == &readonly_data_buffer_impl);
struct wlr_readonly_data_buffer *buffer = wl_container_of(wlr_buffer, buffer, base);
return buffer;
}
static void readonly_data_buffer_destroy(struct wlr_buffer *wlr_buffer) {
struct wlr_readonly_data_buffer *buffer =
readonly_data_buffer_from_buffer(wlr_buffer);
wlr_buffer_finish(wlr_buffer);
free(buffer->saved_data);
free(buffer);
}
static bool readonly_data_buffer_begin_data_ptr_access(struct wlr_buffer *wlr_buffer,
uint32_t flags, void **data, uint32_t *format, size_t *stride) {
struct wlr_readonly_data_buffer *buffer =
readonly_data_buffer_from_buffer(wlr_buffer);
if (buffer->data == NULL) {
return false;
}
if (flags & WLR_BUFFER_DATA_PTR_ACCESS_WRITE) {
return false;
}
*data = (void *)buffer->data;
*format = buffer->format;
*stride = buffer->stride;
return true;
}
static void readonly_data_buffer_end_data_ptr_access(struct wlr_buffer *wlr_buffer) {
// This space is intentionally left blank
}
static const struct wlr_buffer_impl readonly_data_buffer_impl = {
.destroy = readonly_data_buffer_destroy,
.begin_data_ptr_access = readonly_data_buffer_begin_data_ptr_access,
.end_data_ptr_access = readonly_data_buffer_end_data_ptr_access,
};
struct wlr_readonly_data_buffer *readonly_data_buffer_create(uint32_t format,
size_t stride, uint32_t width, uint32_t height, const void *data) {
struct wlr_readonly_data_buffer *buffer = calloc(1, sizeof(*buffer));
if (buffer == NULL) {
return NULL;
}
wlr_buffer_init(&buffer->base, &readonly_data_buffer_impl, width, height);
buffer->data = data;
buffer->format = format;
buffer->stride = stride;
return buffer;
}
bool readonly_data_buffer_drop(struct wlr_readonly_data_buffer *buffer) {
bool ok = true;
if (buffer->base.n_locks > 0) {
size_t size = buffer->stride * buffer->base.height;
buffer->saved_data = malloc(size);
if (buffer->saved_data == NULL) {
wlr_log_errno(WLR_ERROR, "Allocation failed");
ok = false;
buffer->data = NULL;
// We can't destroy the buffer, or we risk use-after-free in the
// consumers. We can't allow accesses to buffer->data anymore, so
// set it to NULL and make subsequent begin_data_ptr_access()
// calls fail.
} else {
memcpy(buffer->saved_data, buffer->data, size);
buffer->data = buffer->saved_data;
}
}
wlr_buffer_drop(&buffer->base);
return ok;
}
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