tdb2: change to using a hash tree.

[ccan] / ccan / tdb2 / io.c

diff --git a/ccan/tdb2/io.c b/ccan/tdb2/io.c
index a973adde65df7658c50a001c75fbc931bb852153..6cb1bdda6d5e68646dfe81976b73477f47445902 100644 (file)
--- a/ccan/tdb2/io.c
+++ b/ccan/tdb2/io.c
@@ -26,6 +26,7 @@
    License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */
 #include "private.h"
+#include <assert.h>
 #include <ccan/likely/likely.h>
 
 void tdb_munmap(struct tdb_context *tdb)
@@ -72,6 +73,10 @@ static int tdb_oob(struct tdb_context *tdb, tdb_off_t len, bool probe)
        struct stat st;
        int ret;
 
+       /* FIXME: We can't hold pointers during this: we could unmap! */
+       /* (We currently do this in traverse!) */
+//     assert(!tdb->direct_access || tdb_has_expansion_lock(tdb));
+
        if (len <= tdb->map_size)
                return 0;
        if (tdb->flags & TDB_INTERNAL) {
@@ -375,44 +380,29 @@ int tdb_write_off(struct tdb_context *tdb, tdb_off_t off, tdb_off_t val)
        return tdb_write_convert(tdb, off, &val, sizeof(val));
 }
 
-/* read a lump of data, allocating the space for it */
-void *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len)
+static void *_tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset,
+                            tdb_len_t len, unsigned int prefix)
 {
        void *buf;
 
        /* some systems don't like zero length malloc */
-       buf = malloc(len ? len : 1);
+       buf = malloc(prefix + len ? prefix + len : 1);
        if (unlikely(!buf)) {
                tdb->ecode = TDB_ERR_OOM;
                tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
                         "tdb_alloc_read malloc failed len=%lld\n",
-                        (long long)len);
-       } else if (unlikely(tdb->methods->read(tdb, offset, buf, len))) {
+                        (long long)prefix + len);
+       } else if (unlikely(tdb->methods->read(tdb, offset, buf+prefix, len))) {
                free(buf);
                buf = NULL;
        }
        return buf;
 }
 
-uint64_t hash_record(struct tdb_context *tdb, tdb_off_t off)
+/* read a lump of data, allocating the space for it */
+void *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len)
 {
-       struct tdb_used_record pad, *r;
-       const void *key;
-       uint64_t klen, hash;
-
-       r = tdb_get(tdb, off, &pad, sizeof(pad));
-       if (!r)
-               /* FIXME */
-               return 0;
-
-       klen = rec_key_length(r);
-       key = tdb_access_read(tdb, off + sizeof(pad), klen, false);
-       if (!key)
-               return 0;
-
-       hash = tdb_hash(tdb, key, klen);
-       tdb_access_release(tdb, key);
-       return hash;
+       return _tdb_alloc_read(tdb, offset, len, 0);
 }
 
 static int fill(struct tdb_context *tdb,
@@ -474,19 +464,57 @@ static int tdb_expand_file(struct tdb_context *tdb, tdb_len_t addition)
        return 0;
 }
 
+/* This is only neded for tdb_access_commit, but used everywhere to simplify. */
+struct tdb_access_hdr {
+       tdb_off_t off;
+       tdb_len_t len;
+       bool convert;
+};
+
 const void *tdb_access_read(struct tdb_context *tdb,
                            tdb_off_t off, tdb_len_t len, bool convert)
 {
-       const void *ret = NULL;
+       const void *ret = NULL; 
 
        if (likely(!(tdb->flags & TDB_CONVERT)))
                ret = tdb_direct(tdb, off, len);
 
        if (!ret) {
-               ret = tdb_alloc_read(tdb, off, len);
-               if (convert)
-                       tdb_convert(tdb, (void *)ret, len);
-       }
+               struct tdb_access_hdr *hdr;
+               hdr = _tdb_alloc_read(tdb, off, len, sizeof(*hdr));
+               if (hdr) {
+                       ret = hdr + 1;
+                       if (convert)
+                               tdb_convert(tdb, (void *)ret, len);
+               }
+       } else
+               tdb->direct_access++;
+
+       return ret;
+}
+
+void *tdb_access_write(struct tdb_context *tdb,
+                      tdb_off_t off, tdb_len_t len, bool convert)
+{
+       void *ret = NULL;
+
+       if (likely(!(tdb->flags & TDB_CONVERT)))
+               ret = tdb_direct(tdb, off, len);
+
+       if (!ret) {
+               struct tdb_access_hdr *hdr;
+               hdr = _tdb_alloc_read(tdb, off, len, sizeof(*hdr));
+               if (hdr) {
+                       hdr->off = off;
+                       hdr->len = len;
+                       hdr->convert = convert;
+                       ret = hdr + 1;
+                       if (convert)
+                               tdb_convert(tdb, (void *)ret, len);
+               }
+       } else
+               tdb->direct_access++;
+
        return ret;
 }
 
@@ -495,7 +523,30 @@ void tdb_access_release(struct tdb_context *tdb, const void *p)
        if (!tdb->map_ptr
            || (char *)p < (char *)tdb->map_ptr
            || (char *)p >= (char *)tdb->map_ptr + tdb->map_size)
-               free((void *)p);
+               free((struct tdb_access_hdr *)p - 1);
+       else
+               tdb->direct_access--;
+}
+
+int tdb_access_commit(struct tdb_context *tdb, void *p)
+{
+       int ret = 0;
+
+       if (!tdb->map_ptr
+           || (char *)p < (char *)tdb->map_ptr
+           || (char *)p >= (char *)tdb->map_ptr + tdb->map_size) {
+               struct tdb_access_hdr *hdr;
+
+               hdr = (struct tdb_access_hdr *)p - 1;
+               if (hdr->convert)
+                       ret = tdb_write_convert(tdb, hdr->off, p, hdr->len);
+               else
+                       ret = tdb_write(tdb, hdr->off, p, hdr->len);
+               free(hdr);
+       } else
+               tdb->direct_access--;
+
+       return ret;
 }
 
 #if 0