--- a/src/lib/cache.c	Sun Dec 27 22:01:17 2009 +0200
+++ b/src/lib/cache.c	Sun Dec 27 23:14:10 2009 +0200
@@ -1,55 +1,234 @@
 #include "cache.h"
 
-static int pt_cache_new (struct pt_cache **cache_ptr)
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+
+
+static int pt_cache_new (struct pt_cache **cache_ptr, const char *path)
 {
     struct pt_cache *cache;
 
+    // alloc
     if ((cache = calloc(1, sizeof(*cache))) == NULL)
         return -1;
 
+    if ((cache->path = strdup(path)) == NULL)
+        goto error;
+
+    // init
+    cache->fd = -1;
+
+    // ok
+    *cache_ptr = cache;
+
+    return 0;
+
+error:
+    // cleanup
+    if (cache)
+        pt_cache_destroy(cache);
+
+    return -1;
+}
+
+int pt_cache_open (struct pt_cache **cache_ptr, const char *path, int mode)
+{
+    struct pt_cache *cache;
+    
+    // alloc
+    if (pt_cache_new(&cache, path))
+        return -1;
+    
     // ok
     *cache_ptr = cache;
 
     return 0;
 }
 
-int pt_cache_open (struct pt_cache **cache_ptr, struct pt_image *img, int mode)
-{
-    struct pt_cache *cache;
-    
-    // alloc
-    if (pt_cache_new(&cache))
-        return -1;
-
-    
-}
-
-bool pt_cache_fresh (struct pt_cache *cache)
+int pt_cache_stale (struct pt_cache *cache, const char *orig_path)
 {
     // TODO: stat + mtime
     return false;
 }
 
 /**
+ * Abort any incomplete open operation, cleaning up
+ */
+static void pt_cache_abort (struct pt_cache *cache)
+{
+    if (cache->mmap != NULL) {
+        munmap(cache->mmap, cache->size);
+
+        cache->mmap = NULL;
+    }
+
+    if (cache->fd >= 0) {
+        close(cache->fd);
+
+        cache->fd = -1;
+    }
+}
+
+/**
+ * Open the cache file as an fd.
+ *
+ * XXX: needs locking
+ */
+static int pt_cache_open_fd (struct pt_cache *cache, int *fd_ptr)
+{
+    int fd;
+    int flags = 0;
+
+    // determine open flags
+    // XXX: O_RDONLY | O_WRONLY == O_RDWR?
+    if (cache->mode & PT_IMG_READ)
+        flags |= O_RDONLY;
+
+    if (cache->mode & PT_IMG_WRITE)
+        flags |= (O_WRONLY | O_CREAT);
+
+    // actual open()
+    if ((fd = open(cache->path, flags)) < 0)
+        return -1;
+
+    // ok
+    *fd_ptr = fd;
+
+    return 0;
+}
+
+/**
+ * Mmap the opened cache file from offset PT_CACHE_PAGE, using the calculated size stored in cache->size
+ */
+static int pt_cache_open_mmap (struct pt_cache *cache, void **addr_ptr)
+{
+    int prot = 0;
+    void *addr;
+
+    // determine prot
+    if (cache->mode & PT_IMG_READ)
+        prot |= PROT_READ;
+
+    if (cache->mode & PT_IMG_WRITE)
+        prot |= PROT_WRITE;
+
+    // perform mmap() from second page on
+    if ((addr = mmap(NULL, cache->size, prot, MAP_SHARED, cache->fd, PT_CACHE_PAGE)) == MAP_FAILED)
+        return -1;
+
+    // ok
+    *addr_ptr = addr;
+
+    return 0;
+}
+
+/**
+ * Write out the cache header into the opened file
+ */
+static int pt_cache_write_header (struct pt_cache *cache, const struct pt_cache_header *header)
+{
+    size_t len = sizeof(*header);
+    const char *buf = (const char *) header;
+
+    // seek to start
+    if (lseek(cache->fd, 0, SEEK_SET) != 0)
+        return -1;
+
+    // write out full header
+    while (len) {
+        ssize_t ret;
+        
+        // try and write out the header
+        if ((ret = write(cache->fd, buf, len)) < 0)
+            return -1;
+
+        // update offset
+        buf += ret;
+        len -= ret;
+    }
+
+    // done
+    return 0;
+}
+
+/**
  * Create a new cache file, open it, and write out the header.
  */
-static int pt_cache_create (struct pt_cache *cache, struct pt_cache_header *header)
+static int pt_cache_open_create (struct pt_cache *cache, struct pt_cache_header *header)
 {
-    
+    // open
+    if (pt_cache_open_fd(cache, &cache->fd))
+        return -1;
+
+    // calculate data size
+    cache->size = sizeof(*header) + header->height * header->row_bytes;
+
+    // grow file
+    if (ftruncate(cache->fd, PT_CACHE_PAGE + cache->size) < 0)
+        goto error;
+
+    // open mmap
+    if (pt_cache_open_mmap(cache, (void **) &cache->mmap))
+        goto error;
+
+    // write header
+    if (pt_cache_write_header(cache, header))
+        goto error;
+
+    // done
+    return 0;
+
+error:
+    // cleanup
+    pt_cache_abort(cache);
+
+    return -1;
 }
 
 int pt_cache_update_png (struct pt_cache *cache, png_structp png, png_infop info)
 {
     struct pt_cache_header header;
+    
+    // XXX: check cache_mode
+    // XXX: check image doesn't use any options we don't handle
 
     memset(&header, 0, sizeof(header));
 
     // fill in basic info
-    header->width = png_get_image_width(png, info);
-    header->height = png_get_image_height(png, info);
-    header->bit_depth = png_get_bit_depth(png, info);
-    header->color_type = png_get_color_type(png, info);
+    header.width = png_get_image_width(png, info);
+    header.height = png_get_image_height(png, info);
+    header.bit_depth = png_get_bit_depth(png, info);
+    header.color_type = png_get_color_type(png, info);
 
     // fill in other info
-    header->row_bytes = png_get_rowbytes(png, info);
+    header.row_bytes = png_get_rowbytes(png, info);
+
+    // create and write out header
+    if (pt_cache_open_create(cache, &header))
+        return -1;
+
+    // XXX: pallette etc.
+
+    // write out raw image data a row at a time
+    for (size_t row = 0; row < header.height; row++) {
+        // read row data, non-interlaced
+        png_read_row(png, cache->mmap + row * header.row_bytes, NULL);
+    }
+
+    // done!
+    return 0;
 }
+
+void pt_cache_destroy (struct pt_cache *cache)
+{
+    free(cache->path);
+
+    pt_cache_abort(cache);
+
+    free(cache);
+}