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gimp/app/tile_swap.c

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#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#ifdef USE_PTHREADS
#include <pthread.h>
#endif
#define MAX_OPEN_SWAP_FILES 16
#include "tile_swap.h"
#include "tile_pvt.h" /* ick. */
typedef struct _SwapFile SwapFile;
typedef struct _DefSwapFile DefSwapFile;
typedef struct _Gap Gap;
typedef struct _AsyncSwapArgs AsyncSwapArgs;
struct _SwapFile
{
char *filename;
int swap_num;
SwapFunc swap_func;
gpointer user_data;
int fd;
};
struct _DefSwapFile
{
GList *gaps;
long swap_file_end;
off_t cur_position;
};
struct _Gap
{
long start;
long end;
};
struct _AsyncSwapArgs
{
DefSwapFile *def_swap_file;
int fd;
Tile *tile;
};
static void tile_swap_init (void);
static guint tile_swap_hash (int *key);
static gint tile_swap_compare (int *a,
int *b);
static void tile_swap_command (Tile *tile,
int command);
static void tile_swap_open (SwapFile *swap_file);
static int tile_swap_default (int fd,
Tile *tile,
int cmd,
gpointer user_data);
static void tile_swap_default_in (DefSwapFile *def_swap_file,
int fd,
Tile *tile);
static void tile_swap_default_in_async (DefSwapFile *def_swap_file,
int fd,
Tile *tile);
static void tile_swap_default_out (DefSwapFile *def_swap_file,
int fd,
Tile *tile);
static void tile_swap_default_delete (DefSwapFile *def_swap_file,
int fd,
Tile *tile);
static long tile_swap_find_offset (DefSwapFile *def_swap_file,
int fd,
int bytes);
static void tile_swap_resize (DefSwapFile *def_swap_file,
int fd,
long new_size);
static Gap* tile_swap_gap_new (long start,
long end);
static void tile_swap_gap_destroy (Gap *gap);
#ifdef USE_PTHREADS
static void* tile_swap_in_thread (void *);
#endif
static int initialize = TRUE;
static GHashTable *swap_files = NULL;
static GList *open_swap_files = NULL;
static int nopen_swap_files = 0;
static int next_swap_num = 1;
static long swap_file_grow = 16 * TILE_WIDTH * TILE_HEIGHT * 4;
#ifdef USE_PTHREADS
static pthread_mutex_t swapfile_mutex = PTHREAD_MUTEX_INITIALIZER;
/* async_swapin_mutex protects only the list, not the tiles therein */
static pthread_t swapin_thread;
static pthread_mutex_t async_swapin_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t async_swapin_signal = PTHREAD_COND_INITIALIZER;
static GSList *async_swapin_tiles = NULL;
static GSList *async_swapin_tiles_end = NULL;
#endif
static gboolean seek_err_msg = TRUE, read_err_msg = TRUE, write_err_msg = TRUE;
static void
tile_swap_print_gaps (DefSwapFile *def_swap_file)
{
GList *gaps;
Gap *gap;
gaps = def_swap_file->gaps;
while (gaps)
{
gap = gaps->data;
gaps = gaps->next;
g_print (" %6ld - %6ld\n", gap->start, gap->end);
}
}
static void
tile_swap_exit1 (gpointer key,
gpointer value,
gpointer data)
{
extern int tile_ref_count;
SwapFile *swap_file;
DefSwapFile *def_swap_file;
if (tile_ref_count != 0)
g_message ("tile ref count balance: %d\n", tile_ref_count);
swap_file = value;
if (swap_file->swap_func == tile_swap_default)
{
def_swap_file = swap_file->user_data;
if (def_swap_file->swap_file_end != 0)
{
g_message ("swap file not empty: \"%s\"\n", swap_file->filename);
tile_swap_print_gaps (def_swap_file);
}
unlink (swap_file->filename);
}
}
void
tile_swap_exit ()
{
if (swap_files)
g_hash_table_foreach (swap_files, tile_swap_exit1, NULL);
}
int
tile_swap_add (char *filename,
SwapFunc swap_func,
gpointer user_data)
{
SwapFile *swap_file;
DefSwapFile *def_swap_file;
#ifdef USE_PTHREADS
pthread_mutex_lock(&swapfile_mutex);
#endif
if (initialize)
tile_swap_init ();
swap_file = g_new (SwapFile, 1);
swap_file->filename = g_strdup (filename);
swap_file->swap_num = next_swap_num++;
if (!swap_func)
{
swap_func = tile_swap_default;
def_swap_file = g_new (DefSwapFile, 1);
def_swap_file->gaps = NULL;
def_swap_file->swap_file_end = 0;
def_swap_file->cur_position = 0;
user_data = def_swap_file;
}
swap_file->swap_func = swap_func;
swap_file->user_data = user_data;
swap_file->fd = -1;
g_hash_table_insert (swap_files, &swap_file->swap_num, swap_file);
#ifdef USE_PTHREADS
pthread_mutex_unlock(&swapfile_mutex);
#endif
return swap_file->swap_num;
}
void
tile_swap_remove (int swap_num)
{
SwapFile *swap_file;
#ifdef USE_PTHREADS
pthread_mutex_lock(&swapfile_mutex);
#endif
if (initialize)
tile_swap_init ();
swap_file = g_hash_table_lookup (swap_files, &swap_num);
if (!swap_file)
goto out;
g_hash_table_remove (swap_files, &swap_num);
if (swap_file->fd != -1)
close (swap_file->fd);
g_free (swap_file);
out:
#ifdef USE_PTHREADS
pthread_mutex_unlock(&swapfile_mutex);
#endif
}
void
tile_swap_in_async (Tile *tile)
{
if (tile->swap_offset == -1)
return;
tile_swap_command (tile, SWAP_IN_ASYNC);
}
void
tile_swap_in (Tile *tile)
{
if (tile->swap_offset == -1)
{
tile_alloc (tile);
return;
}
tile_swap_command (tile, SWAP_IN);
}
void
tile_swap_out (Tile *tile)
{
tile_swap_command (tile, SWAP_OUT);
}
void
tile_swap_delete (Tile *tile)
{
tile_swap_command (tile, SWAP_DELETE);
}
void
tile_swap_compress (int swap_num)
{
tile_swap_command (NULL, SWAP_COMPRESS);
}
static void
tile_swap_init ()
{
if (initialize)
{
initialize = FALSE;
swap_files = g_hash_table_new ((GHashFunc) tile_swap_hash,
(GCompareFunc) tile_swap_compare);
#ifdef USE_PTHREADS
#if 0
pthread_create (&swapin_thread, NULL, &tile_swap_in_thread, NULL);
#endif
#endif
}
}
static guint
tile_swap_hash (int *key)
{
return ((guint) *key);
}
static gint
tile_swap_compare (int *a,
int *b)
{
return (*a == *b);
}
static void
tile_swap_command (Tile *tile,
int command)
{
SwapFile *swap_file;
#ifdef USE_PTHREADS
pthread_mutex_lock(&swapfile_mutex);
#endif
if (initialize)
tile_swap_init ();
do {
swap_file = g_hash_table_lookup (swap_files, &tile->swap_num);
if (!swap_file)
{
g_message ("could not find swap file for tile");
goto out;
}
if (swap_file->fd == -1)
{
tile_swap_open (swap_file);
if (swap_file->fd == -1)
goto out;
}
} while ((* swap_file->swap_func) (swap_file->fd, tile, command, swap_file->user_data));
out:
#ifdef USE_PTHREADS
pthread_mutex_unlock(&swapfile_mutex);
#endif
}
static void
tile_swap_open (SwapFile *swap_file)
{
SwapFile *tmp;
if (swap_file->fd != -1)
return;
if (nopen_swap_files == MAX_OPEN_SWAP_FILES)
{
tmp = open_swap_files->data;
close (tmp->fd);
tmp->fd = -1;
open_swap_files = g_list_remove (open_swap_files, open_swap_files->data);
nopen_swap_files -= 1;
}
swap_file->fd = open (swap_file->filename, O_CREAT|O_RDWR, S_IRUSR|S_IWUSR);
if (swap_file->fd == -1)
{
g_message ("unable to open swap file...BAD THINGS WILL HAPPEN SOON");
return;
}
open_swap_files = g_list_append (open_swap_files, swap_file);
nopen_swap_files += 1;
}
/* The actual swap file code. The swap file consists of tiles
* which have been moved out to disk in order to conserve memory.
* The swap file format is free form. Any tile in memory may
* end up anywhere on disk.
* An actual tile in the swap file consists only of the tile data.
* The offset of the tile on disk is stored in the tile data structure
* in memory.
*/
static int
tile_swap_default (int fd,
Tile *tile,
int cmd,
gpointer user_data)
{
DefSwapFile *def_swap_file;
def_swap_file = (DefSwapFile*) user_data;
switch (cmd)
{
case SWAP_IN:
tile_swap_default_in (def_swap_file, fd, tile);
break;
case SWAP_IN_ASYNC:
tile_swap_default_in_async (def_swap_file, fd, tile);
break;
case SWAP_OUT:
tile_swap_default_out (def_swap_file, fd, tile);
break;
case SWAP_DELETE:
tile_swap_default_delete (def_swap_file, fd, tile);
break;
case SWAP_COMPRESS:
g_message ("tile_swap_default: SWAP_COMPRESS: UNFINISHED");
break;
}
return FALSE;
}
static void
tile_swap_default_in_async (DefSwapFile *def_swap_file,
int fd,
Tile *tile)
{
#if 0 /* disable -- broken */
#ifdef USE_PTHREADS
AsyncSwapArgs *args;
args = g_new(AsyncSwapArgs, 1);
args->def_swap_file = def_swap_file;
args->fd = fd;
args->tile = tile;
/* add this tile to the list of tiles for the async swapin task */
pthread_mutex_lock (&async_swapin_mutex);
g_slist_append (async_swapin_tiles, args);
if (async_swapin_tiles_end)
async_swapin_tiles_end = async_swapin_tiles_end->next;
else
async_swapin_tiles_end = async_swapin_tiles;
pthread_cond_signal (&async_swapin_signal);
pthread_mutex_unlock (&async_swapin_mutex);
#else
/* ignore; it's only a hint anyway */
/* this could be changed to call out to another program that
* tries to make the OS read the data in from disk.
*/
#endif
#endif
return;
}
/* NOTE: if you change this function, check to see if your changes
* apply to tile_swap_in_attempt() near the end of the file. The
* difference is that this version makes guarantees about what it
* provides, but tile_swap_in_attempt() just tries and gives up if
* anything goes wrong.
*
* I'm not sure that it is worthwhile to try to pull out common
* bits; I think the two functions are (at least for now) different
* enough to keep as two functions.
*
* N.B. the mutex on the tile must already have been locked on entry
* to this function. DO NOT LOCK IT HERE.
*/
static void
tile_swap_default_in (DefSwapFile *def_swap_file,
int fd,
Tile *tile)
{
int bytes;
int err;
int nleft;
off_t offset;
err = -1;
if (tile->data)
{
return;
}
if (def_swap_file->cur_position != tile->swap_offset)
{
def_swap_file->cur_position = tile->swap_offset;
offset = lseek (fd, tile->swap_offset, SEEK_SET);
if (offset == -1)
{
if (seek_err_msg)
g_message ("unable to seek to tile location on disk: %d", err);
seek_err_msg = FALSE;
return;
}
}
bytes = tile_size (tile);
tile_alloc (tile);
nleft = bytes;
while (nleft > 0)
{
do {
err = read (fd, tile->data + bytes - nleft, nleft);
} while ((err == -1) && ((errno == EAGAIN) || (errno == EINTR)));
if (err <= 0)
{
if (read_err_msg)
g_message ("unable to read tile data from disk: %d/%d ( %d ) bytes read", err, errno, nleft);
read_err_msg = FALSE;
return;
}
nleft -= err;
}
def_swap_file->cur_position += bytes;
/* Do not delete the swap from the file */
/* tile_swap_default_delete (def_swap_file, fd, tile); */
read_err_msg = seek_err_msg = TRUE;
}
static void
tile_swap_default_out (DefSwapFile *def_swap_file,
int fd,
Tile *tile)
{
int bytes;
int rbytes;
int err;
int nleft;
off_t offset;
bytes = TILE_WIDTH * TILE_HEIGHT * tile->bpp;
rbytes = tile_size (tile);
/* If there is already a valid swap_offset, use it */
if (tile->swap_offset == -1)
tile->swap_offset = tile_swap_find_offset (def_swap_file, fd, bytes);
if (def_swap_file->cur_position != tile->swap_offset)
{
def_swap_file->cur_position = tile->swap_offset;
offset = lseek (fd, tile->swap_offset, SEEK_SET);
if (offset == -1)
{
if (seek_err_msg)
g_message ("unable to seek to tile location on disk: %d", errno);
seek_err_msg = FALSE;
return;
}
}
nleft = rbytes;
while (nleft > 0)
{
err = write (fd, tile->data + rbytes - nleft, nleft);
if (err <= 0)
{
if (write_err_msg)
g_message ("unable to write tile data to disk: %d ( %d ) bytes written", err, nleft);
write_err_msg = FALSE;
return;
}
nleft -= err;
}
def_swap_file->cur_position += rbytes;
/* Do NOT free tile->data because we may be pre-swapping.
* tile->data is freed in tile_cache_zorch_next
*/
tile->dirty = FALSE;
write_err_msg = seek_err_msg = TRUE;
}
static void
tile_swap_default_delete (DefSwapFile *def_swap_file,
int fd,
Tile *tile)
{
GList *tmp;
GList *tmp2;
Gap *gap;
Gap *gap2;
long start;
long end;
if (tile->swap_offset == -1)
return;
start = tile->swap_offset;
end = start + TILE_WIDTH * TILE_HEIGHT * tile->bpp;
tile->swap_offset = -1;
tmp = def_swap_file->gaps;
while (tmp)
{
gap = tmp->data;
if (end == gap->start)
{
gap->start = start;
if (tmp->prev)
{
gap2 = tmp->prev->data;
if (gap->start == gap2->end)
{
gap2->end = gap->end;
tile_swap_gap_destroy (gap);
def_swap_file->gaps = g_list_remove_link (def_swap_file->gaps, tmp);
g_list_free (tmp);
}
}
break;
}
else if (start == gap->end)
{
gap->end = end;
if (tmp->next)
{
gap2 = tmp->next->data;
if (gap->end == gap2->start)
{
gap2->start = gap->start;
tile_swap_gap_destroy (gap);
def_swap_file->gaps = g_list_remove_link (def_swap_file->gaps, tmp);
g_list_free (tmp);
}
}
break;
}
else if (end < gap->start)
{
gap = tile_swap_gap_new (start, end);
tmp2 = g_list_alloc ();
tmp2->data = gap;
tmp2->next = tmp;
tmp2->prev = tmp->prev;
if (tmp->prev)
tmp->prev->next = tmp2;
tmp->prev = tmp2;
if (tmp == def_swap_file->gaps)
def_swap_file->gaps = tmp2;
break;
}
else if (!tmp->next)
{
gap = tile_swap_gap_new (start, end);
tmp->next = g_list_alloc ();
tmp->next->data = gap;
tmp->next->prev = tmp;
break;
}
tmp = tmp->next;
}
if (!def_swap_file->gaps)
{
gap = tile_swap_gap_new (start, end);
def_swap_file->gaps = g_list_append (def_swap_file->gaps, gap);
}
tmp = g_list_last (def_swap_file->gaps);
gap = tmp->data;
if (gap->end == def_swap_file->swap_file_end)
{
tile_swap_resize (def_swap_file, fd, gap->start);
tile_swap_gap_destroy (gap);
def_swap_file->gaps = g_list_remove_link (def_swap_file->gaps, tmp);
g_list_free (tmp);
}
}
static void
tile_swap_resize (DefSwapFile *def_swap_file,
int fd,
long new_size)
{
if (def_swap_file->swap_file_end > new_size)
ftruncate (fd, new_size);
def_swap_file->swap_file_end = new_size;
}
static long
tile_swap_find_offset (DefSwapFile *def_swap_file,
int fd,
int bytes)
{
GList *tmp;
Gap *gap;
long offset;
tmp = def_swap_file->gaps;
while (tmp)
{
gap = tmp->data;
if ((gap->end - gap->start) >= bytes)
{
offset = gap->start;
gap->start += bytes;
if (gap->start == gap->end)
{
tile_swap_gap_destroy (gap);
def_swap_file->gaps = g_list_remove_link (def_swap_file->gaps, tmp);
g_list_free (tmp);
}
return offset;
}
tmp = tmp->next;
}
offset = def_swap_file->swap_file_end;
tile_swap_resize (def_swap_file, fd, def_swap_file->swap_file_end + swap_file_grow);
if ((offset + bytes) < (def_swap_file->swap_file_end))
{
gap = tile_swap_gap_new (offset + bytes, def_swap_file->swap_file_end);
def_swap_file->gaps = g_list_append (def_swap_file->gaps, gap);
}
return offset;
}
static Gap*
tile_swap_gap_new (long start,
long end)
{
Gap *gap;
gap = g_new (Gap, 1);
gap->start = start;
gap->end = end;
return gap;
}
static void
tile_swap_gap_destroy (Gap *gap)
{
g_free (gap);
}
#if USE_PTHREADS
/* go through the list of tiles that are likely to be used soon and
* try to swap them in. If any tile is not in a state to be swapped
* in, ignore it, and the error will get dealt with when the tile
* is really needed -- assuming that the error still happens.
*
* Potential future enhancement: for non-threaded systems, we could
* fork() a process which merely attempts to bring tiles into the
* OS's buffer/page cache, where they will be read into the gimp
* more quickly. This would be pretty trivial, actually.
*/
static void
tile_swap_in_attempt (DefSwapFile *def_swap_file,
int fd,
Tile *tile)
{
int bytes;
int err;
int nleft;
off_t offset;
err = -1;
TILE_MUTEX_LOCK (tile);
if (tile->data)
goto out;
if (!tile->swap_num || !tile->swap_offset)
goto out;
if (def_swap_file->cur_position != tile->swap_offset)
{
def_swap_file->cur_position = tile->swap_offset;
offset = lseek (fd, tile->swap_offset, SEEK_SET);
if (offset == -1)
return;
}
bytes = tile_size (tile);
tile_alloc (tile);
nleft = bytes;
while (nleft > 0)
{
do {
err = read (fd, tile->data + bytes - nleft, nleft);
} while ((err == -1) && ((errno == EAGAIN) || (errno == EINTR)));
if (err <= 0)
{
g_free (tile->data);
return;
}
nleft -= err;
}
def_swap_file->cur_position += bytes;
out:
TILE_MUTEX_UNLOCK (tile);
}
#if 0
static void *
tile_swap_in_thread (void *data)
{
AsyncSwapArgs *args;
GSList *free_item;
while (1)
{
pthread_mutex_lock (&async_swapin_mutex);
if (!async_swapin_tiles)
{
pthread_cond_wait (&async_swapin_signal, &async_swapin_mutex);
}
args = async_swapin_tiles->data;
free_item = async_swapin_tiles;
async_swapin_tiles = async_swapin_tiles->next;
g_slist_free_1(free_item);
if (!async_swapin_tiles)
async_swapin_tiles_end = NULL;
pthread_mutex_unlock (&async_swapin_mutex);
tile_swap_in_attempt(args->def_swap_file, args->fd, args->tile);
g_free(args);
}
}
#endif
#endif
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