dunst/src/wayland/pool-buffer.c
2020-12-28 15:15:59 +01:00

151 lines
3.2 KiB
C

#define _POSIX_C_SOURCE 200112L
#include <cairo/cairo.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <time.h>
#include <unistd.h>
#include <wayland-client.h>
#include <string.h>
#include "pool-buffer.h"
static void randname(char *buf) {
struct timespec ts;
clock_gettime(CLOCK_REALTIME, &ts);
long r = ts.tv_nsec;
for (int i = 0; i < 6; ++i) {
buf[i] = 'A'+(r&15)+(r&16)*2;
r >>= 5;
}
}
static int anonymous_shm_open(void) {
char name[] = "/dunst-XXXXXX";
int retries = 100;
do {
randname(name + strlen(name) - 6);
--retries;
// 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;
}
} while (retries > 0 && errno == EEXIST);
return -1;
}
static int create_shm_file(off_t size) {
int fd = anonymous_shm_open();
if (fd < 0) {
return fd;
}
if (ftruncate(fd, size) < 0) {
close(fd);
return -1;
}
return fd;
}
static void buffer_handle_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_handle_release,
};
static struct pool_buffer *create_buffer(struct wl_shm *shm,
struct pool_buffer *buf, int32_t width, int32_t height) {
const enum wl_shm_format wl_fmt = WL_SHM_FORMAT_ARGB8888;
const cairo_format_t cairo_fmt = CAIRO_FORMAT_ARGB32;
uint32_t stride = cairo_format_stride_for_width(cairo_fmt, width);
size_t size = stride * height;
void *data = NULL;
if (size > 0) {
int fd = create_shm_file(size);
if (fd == -1) {
return NULL;
}
data = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (data == MAP_FAILED) {
close(fd);
return NULL;
}
struct wl_shm_pool *pool = wl_shm_create_pool(shm, fd, size);
buf->buffer =
wl_shm_pool_create_buffer(pool, 0, width, height, stride, wl_fmt);
wl_buffer_add_listener(buf->buffer, &buffer_listener, buf);
wl_shm_pool_destroy(pool);
close(fd);
}
buf->data = data;
buf->size = size;
buf->width = width;
buf->height = height;
buf->surface = cairo_image_surface_create_for_data(data, cairo_fmt, width,
height, stride);
buf->cairo = cairo_create(buf->surface);
buf->pango = pango_cairo_create_context(buf->cairo);
return buf;
}
void finish_buffer(struct pool_buffer *buffer) {
if (buffer->buffer) {
wl_buffer_destroy(buffer->buffer);
}
if (buffer->cairo) {
cairo_destroy(buffer->cairo);
}
if (buffer->surface) {
cairo_surface_destroy(buffer->surface);
}
if (buffer->pango) {
g_object_unref(buffer->pango);
}
if (buffer->data) {
munmap(buffer->data, buffer->size);
}
memset(buffer, 0, sizeof(struct pool_buffer));
}
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) {
finish_buffer(buffer);
}
if (!buffer->buffer) {
if (!create_buffer(shm, buffer, width, height)) {
return NULL;
}
}
return buffer;
}
/* vim: set ft=c tabstop=8 shiftwidth=8 expandtab textwidth=0: */