#include <stdint.h>
#include <glib.h>
-#include "inode.h"
+#include "bluesky.h"
/* Core filesystem. Different proxies, such as the NFSv3 one, interface to
* this, but the core actually tracks the data which is stored. So far we just
* implement an in-memory filesystem, but eventually this will be state which
* is persisted to the cloud. */
+/* Return the current time, in microseconds since the epoch. */
+int64_t bluesky_get_current_time()
+{
+ GTimeVal t;
+ g_get_current_time(&t);
+ return (int64_t)t.tv_sec * 1000000 + t.tv_usec;
+}
-/* Hash a filename for a directory lookup. The string is hashed to a 64-bit
- * value. */
-uint64_t bluesky_directory_hash(gchar *name)
+/* Unfortunately a glib hash table is only guaranteed to be able to store
+ * 32-bit keys if we use the key directly. If we want 64-bit inode numbers,
+ * we'll have to allocate memory to store the 64-bit inumber, and use a pointer
+ * to it. Rather than allocate the memory for the key, we'll just include a
+ * pointer to the 64-bit inum stored in the inode itself, so that we don't need
+ * to do any more memory management. */
+static guint bluesky_fs_key_hash_func(gconstpointer key)
{
- GChecksum *csum = g_checksum_new(G_CHECKSUM_MD5);
- g_checksum_update(csum, (guchar *)name, -1);
+ uint64_t inum = *(const uint64_t *)key;
+ return (guint)inum;
+}
- guint64 hashbytes[2];
- gsize hashsize = sizeof(hashbytes);
- g_checksum_get_digest(csum, (guint8 *)hashbytes, &hashsize);
- return GUINT64_FROM_LE(hashbytes[0]);
+static gboolean bluesky_fs_key_equal_func(gconstpointer a, gconstpointer b)
+{
+ uint64_t i1 = *(const uint64_t *)a;
+ uint64_t i2 = *(const uint64_t *)b;
+ return i1 == i2;
}
-/* Return the current time, in microseconds since the epoch. */
-int64_t bluesky_get_current_time()
+/* Filesystem-level operations. A filesystem is like a directory tree that we
+ * are willing to export. */
+BlueSkyFS *bluesky_new_fs(gchar *name)
{
- GTimeVal t;
- g_get_current_time(&t);
- return t.tv_sec * 1000000 + t.tv_usec;
+ BlueSkyFS *fs = g_new0(BlueSkyFS, 1);
+ fs->lock = g_mutex_new();
+ fs->name = g_strdup(name);
+ fs->inodes = g_hash_table_new(bluesky_fs_key_hash_func,
+ bluesky_fs_key_equal_func);
+ fs->next_inum = BLUESKY_ROOT_INUM + 1;
+
+ return fs;
}
/* Allocate a fresh inode number which has not been used before within a
return inum;
}
-BlueSkyInode *bluesky_new_inode(uint64_t inum)
+BlueSkyInode *bluesky_new_inode(uint64_t inum, BlueSkyFileType type)
{
BlueSkyInode *i = g_new0(BlueSkyInode, 1);
i->lock = g_mutex_new();
+ i->type = type;
i->inum = inum;
+ switch (type) {
+ case BLUESKY_REGULAR:
+ break;
+ case BLUESKY_DIRECTORY:
+ i->dirents = g_sequence_new(bluesky_dirent_destroy);
+ case BLUESKY_BLOCK:
+ case BLUESKY_CHARACTER:
+ case BLUESKY_SYMLINK:
+ case BLUESKY_SOCKET:
+ case BLUESKY_FIFO:
+ break;
+ }
+
return i;
}
-void bluesky_dirent_destroy(BlueSkyDirent *dirent)
+/* Retrieve an inode from the filesystem. Eventually this will be a cache and
+ * so we might need to go fetch the inode from elsewhere; for now all
+ * filesystem state is stored here. */
+BlueSkyInode *bluesky_get_inode(BlueSkyFS *fs, uint64_t inum)
{
- g_free(dirent->name);
- g_free(dirent);
-}
+ BlueSkyInode *inode = NULL;
-gint bluesky_dirent_compare(gconstpointer a, gconstpointer b,
- gpointer unused)
-{
- /* We can't simply subtract the hash values, since they are 64-bit and the
- * result could overflow when converted to a gint. */
- uint64_t hash1 = ((const BlueSkyDirent *)a)->hash;
- uint64_t hash2 = ((const BlueSkyDirent *)b)->hash;
-
- if (hash1 < hash2)
- return -1;
- else if (hash1 > hash2)
- return 1;
- else
- return 0;
+ g_mutex_lock(fs->lock);
+ inode = (BlueSkyInode *)g_hash_table_lookup(fs->inodes, &inum);
+ g_mutex_unlock(fs->lock);
+
+ return inode;
}
-/* Perform a lookup for a file name within a directory. Returns the inode
- * number if found, or 0 if not (0 is never a valid inode number). Should be
- * called with the inode lock already held. */
-uint64_t bluesky_directory_lookup(BlueSkyInode *inode, gchar *name)
+/* Insert an inode into the filesystem inode cache. */
+void bluesky_insert_inode(BlueSkyFS *fs, BlueSkyInode *inode)
{
- g_return_val_if_fail(inode->type != BLUESKY_DIRECTORY, 0);
- g_return_val_if_fail(inode->dirents != NULL, 0);
-
- /* First, construct a hash of the file name. Search the directory for a
- * match, then check to see if it does really match. */
- uint64_t hash = bluesky_directory_hash(name);
-
- BlueSkyDirent d = {name, hash, 0};
- GSequenceIter *i = g_sequence_search(inode->dirents, &d,
- bluesky_dirent_compare, NULL);
-
- if (g_sequence_iter_is_end(i))
- return 0;
- BlueSkyDirent *dirent = g_sequence_get(i);
- if (dirent->hash != hash)
- return 0;
- if (g_strcmp0(name, dirent->name) != 0)
- return 0;
-
- return dirent->inum;
+ g_mutex_lock(fs->lock);
+ g_hash_table_insert(fs->inodes, &inode->inum, inode);
+ g_mutex_unlock(fs->lock);
}
projects / bluesky.git / blobdiff