tdb2: allow multiple chain locks.

[ccan] / ccan / tdb2 / traverse.c

diff --git a/ccan/tdb2/traverse.c b/ccan/tdb2/traverse.c
index 66319dd56764d823dfca54544cfd2ee0d22aea03..f8a2504dcd61489eb23bf7b84c8e0a88ced07f43 100644 (file)
--- a/ccan/tdb2/traverse.c
+++ b/ccan/tdb2/traverse.c
@@ -1,7 +1,7 @@
- /* 
+ /*
    Trivial Database 2: traverse function.
    Copyright (C) Rusty Russell 2010
-   
+
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
@@ -18,41 +18,82 @@
 #include "private.h"
 #include <ccan/likely/likely.h>
 
-static int64_t traverse(struct tdb_context *tdb, int ltype,
-                       tdb_traverse_func fn, void *p)
+int64_t tdb_traverse_(struct tdb_context *tdb,
+                     int (*fn)(struct tdb_context *,
+                               TDB_DATA, TDB_DATA, void *),
+                     void *p)
 {
-       int ret;
+       enum TDB_ERROR ecode;
        struct traverse_info tinfo;
        struct tdb_data k, d;
        int64_t count = 0;
 
-       for (ret = first_in_hash(tdb, ltype, &tinfo, &k, &d.dsize);
-            ret == 1;
-            ret = next_in_hash(tdb, ltype, &tinfo, &k, &d.dsize)) {
+       k.dptr = NULL;
+       for (ecode = first_in_hash(tdb, &tinfo, &k, &d.dsize);
+            ecode == TDB_SUCCESS;
+            ecode = next_in_hash(tdb, &tinfo, &k, &d.dsize)) {
                d.dptr = k.dptr + k.dsize;
                
                count++;
-               if (fn && fn(tdb, k, d, p))
-                       break;
+               if (fn && fn(tdb, k, d, p)) {
+                       free(k.dptr);
+                       tdb->last_error = TDB_SUCCESS;
+                       return count;
+               }
+               free(k.dptr);
        }
 
-       if (ret < 0)
-               return -1;
+       if (ecode != TDB_ERR_NOEXIST) {
+               return tdb->last_error = ecode;
+       }
+       tdb->last_error = TDB_SUCCESS;
        return count;
 }
+       
+enum TDB_ERROR tdb_firstkey(struct tdb_context *tdb, struct tdb_data *key)
+{
+       struct traverse_info tinfo;
+
+       return tdb->last_error = first_in_hash(tdb, &tinfo, key, NULL);
+}
+
+/* We lock twice, not very efficient.  We could keep last key & tinfo cached. */
+enum TDB_ERROR tdb_nextkey(struct tdb_context *tdb, struct tdb_data *key)
+{
+       struct traverse_info tinfo;
+       struct hash_info h;
+       struct tdb_used_record rec;
+
+       tinfo.prev = find_and_lock(tdb, *key, F_RDLCK, &h, &rec, &tinfo);
+       free(key->dptr);
+       if (TDB_OFF_IS_ERR(tinfo.prev)) {
+               return tdb->last_error = tinfo.prev;
+       }
+       tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
+
+       return tdb->last_error = next_in_hash(tdb, &tinfo, key, NULL);
+}
 
-int64_t tdb_traverse(struct tdb_context *tdb, tdb_traverse_func fn, void *p)
+static int wipe_one(struct tdb_context *tdb,
+                   TDB_DATA key, TDB_DATA data, enum TDB_ERROR *ecode)
 {
-       return traverse(tdb, F_WRLCK, fn, p);
+       *ecode = tdb_delete(tdb, key);
+       return (*ecode != TDB_SUCCESS);
 }
-       
-int64_t tdb_traverse_read(struct tdb_context *tdb,
-                         tdb_traverse_func fn, void *p)
+
+enum TDB_ERROR tdb_wipe_all(struct tdb_context *tdb)
 {
-       int64_t ret;
-       bool was_ro = tdb->read_only;
-       tdb->read_only = true;
-       ret = traverse(tdb, F_RDLCK, fn, p);
-       tdb->read_only = was_ro;
-       return ret;
+       enum TDB_ERROR ecode;
+       int64_t count;
+
+       ecode = tdb_allrecord_lock(tdb, F_WRLCK, TDB_LOCK_WAIT, false);
+       if (ecode != TDB_SUCCESS)
+               return tdb->last_error = ecode;
+
+       /* FIXME: Be smarter. */
+       count = tdb_traverse(tdb, wipe_one, &ecode);
+       if (count < 0)
+               ecode = count;
+       tdb_allrecord_unlock(tdb, F_WRLCK);
+       return tdb->last_error = ecode;
 }