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wayland: Factor out the general SHM buffer allocation/free functions …
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…from the cursor code
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@Kontrabant
Kontrabant committed Oct 7, 2024
1 parent e4126d8 commit ea77d1d
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Showing 3 changed files with 218 additions and 149 deletions.
161 changes: 12 additions & 149 deletions src/video/wayland/SDL_waylandmouse.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,10 +25,7 @@

#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>
#include <limits.h>
#include <signal.h>
#include <errno.h>

#include "../SDL_sysvideo.h"

Expand All @@ -40,6 +37,7 @@

#include "wayland-cursor.h"
#include "SDL_waylandmouse.h"
#include "SDL_waylandshmbuffer.h"

#include "cursor-shape-v1-client-protocol.h"

Expand All @@ -50,7 +48,7 @@ static int Wayland_SetRelativeMouseMode(SDL_bool enabled);

typedef struct
{
struct wl_buffer *buffer;
struct Wayland_SHMBuffer shmBuffer;
struct wl_surface *surface;

int hot_x, hot_y;
Expand All @@ -60,8 +58,6 @@ typedef struct
* When shm_data is NULL, system_cursor must be valid
*/
SDL_SystemCursor system_cursor;
void *shm_data;
size_t shm_data_size;
} Wayland_CursorData;

#ifdef SDL_USE_LIBDBUS
Expand Down Expand Up @@ -285,144 +281,14 @@ static SDL_bool wayland_get_system_cursor(SDL_VideoData *vdata, Wayland_CursorDa
}

/* ... Set the cursor data, finally. */
cdata->buffer = WAYLAND_wl_cursor_image_get_buffer(cursor->images[0]);
cdata->shmBuffer.wl_buffer = WAYLAND_wl_cursor_image_get_buffer(cursor->images[0]);
cdata->hot_x = cursor->images[0]->hotspot_x;
cdata->hot_y = cursor->images[0]->hotspot_y;
cdata->w = cursor->images[0]->width;
cdata->h = cursor->images[0]->height;
return SDL_TRUE;
}

static int set_tmp_file_size(int fd, off_t size)
{
#ifdef HAVE_POSIX_FALLOCATE
sigset_t set, old_set;
int ret;

/* SIGALRM can potentially block a large posix_fallocate() operation
* from succeeding, so block it.
*/
sigemptyset(&set);
sigaddset(&set, SIGALRM);
sigprocmask(SIG_BLOCK, &set, &old_set);

do {
ret = posix_fallocate(fd, 0, size);
} while (ret == EINTR);

sigprocmask(SIG_SETMASK, &old_set, NULL);

if (ret == 0) {
return 0;
}
else if (ret != EINVAL && errno != EOPNOTSUPP) {
return -1;
}
#endif

if (ftruncate(fd, size) < 0) {
return -1;
}
return 0;
}

static int wayland_create_tmp_file(off_t size)
{
int fd;

#ifdef HAVE_MEMFD_CREATE
fd = memfd_create("SDL", MFD_CLOEXEC | MFD_ALLOW_SEALING);
if (fd >= 0) {
fcntl(fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_SEAL);
} else
#endif
{
static const char template[] = "/sdl-shared-XXXXXX";
char *xdg_path;
char tmp_path[PATH_MAX];

xdg_path = SDL_getenv("XDG_RUNTIME_DIR");
if (!xdg_path) {
return -1;
}

SDL_strlcpy(tmp_path, xdg_path, PATH_MAX);
SDL_strlcat(tmp_path, template, PATH_MAX);

fd = mkostemp(tmp_path, O_CLOEXEC);
if (fd < 0) {
return -1;
}

/* Need to manually unlink the temp files, or they can persist after close and fill up the temp storage. */
unlink(tmp_path);
}

if (set_tmp_file_size(fd, size) < 0) {
close(fd);
return -1;
}

return fd;
}

static void mouse_buffer_release(void *data, struct wl_buffer *buffer)
{
}

static const struct wl_buffer_listener mouse_buffer_listener = {
mouse_buffer_release
};

static int create_buffer_from_shm(Wayland_CursorData *d,
int width,
int height,
uint32_t format)
{
SDL_VideoDevice *vd = SDL_GetVideoDevice();
SDL_VideoData *data = (SDL_VideoData *)vd->driverdata;
struct wl_shm_pool *shm_pool;
int shm_fd;

int stride = width * 4;
d->shm_data_size = stride * height;

shm_fd = wayland_create_tmp_file(d->shm_data_size);
if (shm_fd < 0) {
return SDL_SetError("Creating mouse cursor buffer failed.");
}

d->shm_data = mmap(NULL,
d->shm_data_size,
PROT_READ | PROT_WRITE,
MAP_SHARED,
shm_fd,
0);
if (d->shm_data == MAP_FAILED) {
d->shm_data = NULL;
close(shm_fd);
return SDL_SetError("mmap() failed.");
}

SDL_assert(d->shm_data != NULL);

shm_pool = wl_shm_create_pool(data->shm, shm_fd, d->shm_data_size);
d->buffer = wl_shm_pool_create_buffer(shm_pool,
0,
width,
height,
stride,
format);
wl_buffer_add_listener(d->buffer,
&mouse_buffer_listener,
d);

wl_shm_pool_destroy(shm_pool);
close(shm_fd);

return 0;
}

static SDL_Cursor *Wayland_CreateCursor(SDL_Surface *surface, int hot_x, int hot_y)
{
SDL_Cursor *cursor;
Expand All @@ -440,10 +306,9 @@ static SDL_Cursor *Wayland_CreateCursor(SDL_Surface *surface, int hot_x, int hot
cursor->driverdata = (void *)data;

/* Allocate shared memory buffer for this cursor */
if (create_buffer_from_shm(data,
surface->w,
if (Wayland_AllocSHMBuffer(surface->w,
surface->h,
WL_SHM_FORMAT_ARGB8888) < 0) {
&data->shmBuffer) < 0) {
SDL_free(cursor->driverdata);
SDL_free(cursor);
return NULL;
Expand All @@ -452,7 +317,7 @@ static SDL_Cursor *Wayland_CreateCursor(SDL_Surface *surface, int hot_x, int hot
/* Wayland requires premultiplied alpha for its surfaces. */
SDL_PremultiplyAlpha(surface->w, surface->h,
surface->format->format, surface->pixels, surface->pitch,
SDL_PIXELFORMAT_ARGB8888, data->shm_data, surface->w * 4);
SDL_PIXELFORMAT_ARGB8888, data->shmBuffer.shm_data, surface->w * 4);

data->surface = wl_compositor_create_surface(wd->compositor);
wl_surface_set_user_data(data->surface, NULL);
Expand Down Expand Up @@ -506,12 +371,10 @@ static SDL_Cursor *Wayland_CreateDefaultCursor()

static void Wayland_FreeCursorData(Wayland_CursorData *d)
{
if (d->buffer) {
if (d->shm_data) {
wl_buffer_destroy(d->buffer);
munmap(d->shm_data, d->shm_data_size);
}
d->buffer = NULL;
if (d->shmBuffer.shm_data) {
Wayland_ReleaseSHMBuffer(&d->shmBuffer);
} else {
d->shmBuffer.wl_buffer = NULL;
}

if (d->surface) {
Expand Down Expand Up @@ -602,7 +465,7 @@ static int Wayland_ShowCursor(SDL_Cursor *cursor)
Wayland_CursorData *data = cursor->driverdata;

/* TODO: High-DPI custom cursors? -flibit */
if (!data->shm_data) {
if (!data->shmBuffer.shm_data) {
if (input->cursor_shape) {
Wayland_SetSystemCursorShape(input, data->system_cursor);

Expand All @@ -625,7 +488,7 @@ static int Wayland_ShowCursor(SDL_Cursor *cursor)
data->surface,
data->hot_x / scale,
data->hot_y / scale);
wl_surface_attach(data->surface, data->buffer, 0, 0);
wl_surface_attach(data->surface, data->shmBuffer.wl_buffer, 0, 0);
wl_surface_damage(data->surface, 0, 0, data->w, data->h);
wl_surface_commit(data->surface);

Expand Down
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