terom@0: #include "cache.h"
terom@0: 
terom@1: #include <stdlib.h>
terom@1: #include <unistd.h>
terom@1: #include <sys/types.h>
terom@1: #include <sys/stat.h>
terom@1: #include <fcntl.h>
terom@1: #include <sys/mman.h>
terom@2: #include <errno.h>
terom@1: 
terom@1: 
terom@1: 
terom@1: static int pt_cache_new (struct pt_cache **cache_ptr, const char *path)
terom@0: {
terom@0:     struct pt_cache *cache;
terom@0: 
terom@1:     // alloc
terom@0:     if ((cache = calloc(1, sizeof(*cache))) == NULL)
terom@0:         return -1;
terom@0: 
terom@1:     if ((cache->path = strdup(path)) == NULL)
terom@1:         goto error;
terom@1: 
terom@1:     // init
terom@1:     cache->fd = -1;
terom@1: 
terom@1:     // ok
terom@1:     *cache_ptr = cache;
terom@1: 
terom@1:     return 0;
terom@1: 
terom@1: error:
terom@1:     // cleanup
terom@1:     if (cache)
terom@1:         pt_cache_destroy(cache);
terom@1: 
terom@1:     return -1;
terom@1: }
terom@1: 
terom@1: int pt_cache_open (struct pt_cache **cache_ptr, const char *path, int mode)
terom@1: {
terom@1:     struct pt_cache *cache;
terom@1:     
terom@1:     // alloc
terom@1:     if (pt_cache_new(&cache, path))
terom@1:         return -1;
terom@1:     
terom@0:     // ok
terom@0:     *cache_ptr = cache;
terom@0: 
terom@0:     return 0;
terom@0: }
terom@0: 
terom@2: int pt_cache_stale (struct pt_cache *cache, const char *img_path)
terom@0: {
terom@2:     struct stat st_img, st_cache;
terom@2:     
terom@2:     // test original file
terom@2:     if (stat(img_path, &st_img) < 0)
terom@2:         return -1;
terom@2:     
terom@2:     // test cache file
terom@2:     if (stat(cache->path, &st_cache) < 0) {
terom@2:         // always stale if it doesn't exist yet
terom@2:         if (errno == ENOENT)
terom@2:             return 1;
terom@2:         else
terom@2:             return -1;
terom@2:     }
terom@2: 
terom@2:     // compare mtime
terom@2:     return (st_img.st_mtime > st_cache.st_mtime);
terom@0: }
terom@0: 
terom@0: /**
terom@1:  * Abort any incomplete open operation, cleaning up
terom@1:  */
terom@1: static void pt_cache_abort (struct pt_cache *cache)
terom@1: {
terom@1:     if (cache->mmap != NULL) {
terom@1:         munmap(cache->mmap, cache->size);
terom@1: 
terom@1:         cache->mmap = NULL;
terom@1:     }
terom@1: 
terom@1:     if (cache->fd >= 0) {
terom@1:         close(cache->fd);
terom@1: 
terom@1:         cache->fd = -1;
terom@1:     }
terom@1: }
terom@1: 
terom@1: /**
terom@1:  * Open the cache file as an fd.
terom@1:  *
terom@1:  * XXX: needs locking
terom@1:  */
terom@1: static int pt_cache_open_fd (struct pt_cache *cache, int *fd_ptr)
terom@1: {
terom@1:     int fd;
terom@1:     int flags = 0;
terom@1: 
terom@1:     // determine open flags
terom@1:     // XXX: O_RDONLY | O_WRONLY == O_RDWR?
terom@1:     if (cache->mode & PT_IMG_READ)
terom@1:         flags |= O_RDONLY;
terom@1: 
terom@1:     if (cache->mode & PT_IMG_WRITE)
terom@1:         flags |= (O_WRONLY | O_CREAT);
terom@1: 
terom@1:     // actual open()
terom@1:     if ((fd = open(cache->path, flags)) < 0)
terom@1:         return -1;
terom@1: 
terom@1:     // ok
terom@1:     *fd_ptr = fd;
terom@1: 
terom@1:     return 0;
terom@1: }
terom@1: 
terom@1: /**
terom@1:  * Mmap the opened cache file from offset PT_CACHE_PAGE, using the calculated size stored in cache->size
terom@1:  */
terom@1: static int pt_cache_open_mmap (struct pt_cache *cache, void **addr_ptr)
terom@1: {
terom@1:     int prot = 0;
terom@1:     void *addr;
terom@1: 
terom@1:     // determine prot
terom@1:     if (cache->mode & PT_IMG_READ)
terom@1:         prot |= PROT_READ;
terom@1: 
terom@1:     if (cache->mode & PT_IMG_WRITE)
terom@1:         prot |= PROT_WRITE;
terom@1: 
terom@1:     // perform mmap() from second page on
terom@1:     if ((addr = mmap(NULL, cache->size, prot, MAP_SHARED, cache->fd, PT_CACHE_PAGE)) == MAP_FAILED)
terom@1:         return -1;
terom@1: 
terom@1:     // ok
terom@1:     *addr_ptr = addr;
terom@1: 
terom@1:     return 0;
terom@1: }
terom@1: 
terom@1: /**
terom@1:  * Write out the cache header into the opened file
terom@1:  */
terom@1: static int pt_cache_write_header (struct pt_cache *cache, const struct pt_cache_header *header)
terom@1: {
terom@1:     size_t len = sizeof(*header);
terom@1:     const char *buf = (const char *) header;
terom@1: 
terom@1:     // seek to start
terom@1:     if (lseek(cache->fd, 0, SEEK_SET) != 0)
terom@1:         return -1;
terom@1: 
terom@1:     // write out full header
terom@1:     while (len) {
terom@1:         ssize_t ret;
terom@1:         
terom@1:         // try and write out the header
terom@1:         if ((ret = write(cache->fd, buf, len)) < 0)
terom@1:             return -1;
terom@1: 
terom@1:         // update offset
terom@1:         buf += ret;
terom@1:         len -= ret;
terom@1:     }
terom@1: 
terom@1:     // done
terom@1:     return 0;
terom@1: }
terom@1: 
terom@1: /**
terom@0:  * Create a new cache file, open it, and write out the header.
terom@0:  */
terom@1: static int pt_cache_open_create (struct pt_cache *cache, struct pt_cache_header *header)
terom@0: {
terom@2:     // no access
terom@2:     if (!(cache->mode & PT_IMG_WRITE)) {
terom@2:         errno = EPERM;
terom@2:         return -1;
terom@2:     }
terom@2: 
terom@1:     // open
terom@1:     if (pt_cache_open_fd(cache, &cache->fd))
terom@1:         return -1;
terom@1: 
terom@1:     // calculate data size
terom@1:     cache->size = sizeof(*header) + header->height * header->row_bytes;
terom@1: 
terom@1:     // grow file
terom@1:     if (ftruncate(cache->fd, PT_CACHE_PAGE + cache->size) < 0)
terom@1:         goto error;
terom@1: 
terom@1:     // open mmap
terom@1:     if (pt_cache_open_mmap(cache, (void **) &cache->mmap))
terom@1:         goto error;
terom@1: 
terom@1:     // write header
terom@1:     if (pt_cache_write_header(cache, header))
terom@1:         goto error;
terom@1: 
terom@1:     // done
terom@1:     return 0;
terom@1: 
terom@1: error:
terom@1:     // cleanup
terom@1:     pt_cache_abort(cache);
terom@1: 
terom@1:     return -1;
terom@0: }
terom@0: 
terom@0: int pt_cache_update_png (struct pt_cache *cache, png_structp png, png_infop info)
terom@0: {
terom@0:     struct pt_cache_header header;
terom@1:     
terom@1:     // XXX: check cache_mode
terom@1:     // XXX: check image doesn't use any options we don't handle
terom@0: 
terom@0:     memset(&header, 0, sizeof(header));
terom@0: 
terom@0:     // fill in basic info
terom@1:     header.width = png_get_image_width(png, info);
terom@1:     header.height = png_get_image_height(png, info);
terom@1:     header.bit_depth = png_get_bit_depth(png, info);
terom@1:     header.color_type = png_get_color_type(png, info);
terom@0: 
terom@0:     // fill in other info
terom@1:     header.row_bytes = png_get_rowbytes(png, info);
terom@1: 
terom@1:     // create and write out header
terom@1:     if (pt_cache_open_create(cache, &header))
terom@1:         return -1;
terom@1: 
terom@1:     // XXX: pallette etc.
terom@1: 
terom@1:     // write out raw image data a row at a time
terom@1:     for (size_t row = 0; row < header.height; row++) {
terom@1:         // read row data, non-interlaced
terom@1:         png_read_row(png, cache->mmap + row * header.row_bytes, NULL);
terom@1:     }
terom@1: 
terom@1:     // done!
terom@1:     return 0;
terom@0: }
terom@1: 
terom@1: void pt_cache_destroy (struct pt_cache *cache)
terom@1: {
terom@1:     free(cache->path);
terom@1: 
terom@1:     pt_cache_abort(cache);
terom@1: 
terom@1:     free(cache);
terom@1: }