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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copied from https://github.com/swaywm/sway
*
* Copyright (C) 2016-2017 Drew DeVault
*/
#define _POSIX_C_SOURCE 200809L
#include <cairo.h>
#include <errno.h>
#include <fcntl.h>
#include <pango/pangocairo.h>
#include <stdio.h>
#include <sys/mman.h>
#include <time.h>
#include <unistd.h>
#include "pool-buffer.h"
static int anonymous_shm_open(void)
{
int retries = 100;
do {
// try a probably-unique name
struct timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
pid_t pid = getpid();
char name[50];
snprintf(name, sizeof(name), "/labnag-%x-%x",
(unsigned int)pid, (unsigned int)ts.tv_nsec);
// shm_open guarantees that O_CLOEXEC is set
int fd = shm_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
if (fd >= 0) {
shm_unlink(name);
return fd;
}
--retries;
} while (retries > 0 && errno == EEXIST);
return -1;
}
static void buffer_release(void *data, struct wl_buffer *wl_buffer)
{
struct pool_buffer *buffer = data;
buffer->busy = false;
}
static const struct wl_buffer_listener buffer_listener = {
.release = buffer_release
};
static struct pool_buffer *create_buffer(struct wl_shm *shm,
struct pool_buffer *buf, int32_t width, int32_t height,
uint32_t format)
{
uint32_t stride = width * 4;
size_t size = stride * height;
int fd = anonymous_shm_open();
if (fd == -1) {
return NULL;
}
if (ftruncate(fd, size) < 0) {
close(fd);
return NULL;
}
void *data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
struct wl_shm_pool *pool = wl_shm_create_pool(shm, fd, size);
buf->buffer = wl_shm_pool_create_buffer(pool, 0,
width, height, stride, format);
wl_shm_pool_destroy(pool);
close(fd);
buf->size = size;
buf->width = width;
buf->height = height;
buf->data = data;
buf->surface = cairo_image_surface_create_for_data(data,
CAIRO_FORMAT_ARGB32, width, height, stride);
buf->cairo = cairo_create(buf->surface);
buf->pango = pango_cairo_create_context(buf->cairo);
wl_buffer_add_listener(buf->buffer, &buffer_listener, buf);
return buf;
}
void destroy_buffer(struct pool_buffer *buffer)
{
if (buffer->buffer) {
wl_buffer_destroy(buffer->buffer);
buffer->buffer = NULL;
}
if (buffer->cairo) {
cairo_destroy(buffer->cairo);
buffer->cairo = NULL;
}
if (buffer->surface) {
cairo_surface_destroy(buffer->surface);
buffer->surface = NULL;
}
if (buffer->pango) {
g_object_unref(buffer->pango);
buffer->pango = NULL;
}
if (buffer->data) {
munmap(buffer->data, buffer->size);
buffer->data = NULL;
}
}
struct pool_buffer *get_next_buffer(struct wl_shm *shm,
struct pool_buffer pool[static 2], uint32_t width, uint32_t height)
{
struct pool_buffer *buffer = NULL;
for (size_t i = 0; i < 2; ++i) {
if (pool[i].busy) {
continue;
}
buffer = &pool[i];
}
if (!buffer) {
return NULL;
}
if (buffer->width != width || buffer->height != height) {
destroy_buffer(buffer);
}
if (!buffer->buffer) {
if (!create_buffer(shm, buffer, width, height,
WL_SHM_FORMAT_ARGB8888)) {
return NULL;
}
}
buffer->busy = true;
return buffer;
}
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