lib/dbwrap: make it possible to delete/store the current record during traverse

metze

Autobuild-User: Stefan Metzmacher <metze@samba.org>
Autobuild-Date: Thu May 31 02:50:09 CEST 2012 on sn-devel-104

diff --git a/lib/dbwrap/dbwrap_rbt.c b/lib/dbwrap/dbwrap_rbt.c
index 2cc52b1da61597ca9d005e0aaa460248733cad3d..3dca3ba793f9fff18f8427203fa90db03a9b155e 100644 (file)
--- a/lib/dbwrap/dbwrap_rbt.c
+++ b/lib/dbwrap/dbwrap_rbt.c
@@ -206,6 +206,17 @@ static NTSTATUS db_rbt_delete(struct db_record *rec)
 
        return NT_STATUS_OK;
 }
+
+static NTSTATUS db_rbt_store_deny(struct db_record *rec, TDB_DATA data, int flag)
+{
+       return NT_STATUS_MEDIA_WRITE_PROTECTED;
+}
+
+static NTSTATUS db_rbt_delete_deny(struct db_record *rec)
+{
+       return NT_STATUS_MEDIA_WRITE_PROTECTED;
+}
+
 struct db_rbt_search_result {
        TDB_DATA key;
        TDB_DATA val;
@@ -346,27 +357,47 @@ static NTSTATUS db_rbt_parse_record(struct db_context *db, TDB_DATA key,
        return NT_STATUS_OK;
 }
 
-static int db_rbt_traverse_internal(struct rb_node *n,
+static int db_rbt_traverse_internal(struct db_context *db,
+                                   struct rb_node *n,
                                    int (*f)(struct db_record *db,
                                             void *private_data),
-                                   void *private_data, uint32_t* count)
+                                   void *private_data, uint32_t* count,
+                                   bool rw)
 {
-       struct db_rbt_node *r;
+       struct rb_node *rb_right;
+       struct rb_node *rb_left;
        struct db_record rec;
+       struct db_rbt_rec rec_priv;
        int ret;
 
        if (n == NULL) {
                return 0;
        }
 
-       ret = db_rbt_traverse_internal(n->rb_left, f, private_data, count);
+       rb_left = n->rb_left;
+       rb_right = n->rb_right;
+
+       ret = db_rbt_traverse_internal(db, rb_left, f, private_data, count, rw);
        if (ret != 0) {
                return ret;
        }
 
-       r = db_rbt2node(n);
+       ZERO_STRUCT(rec_priv);
+       rec_priv.node = db_rbt2node(n);
+       /* n might be altered by the callback function */
+       n = NULL;
+
        ZERO_STRUCT(rec);
-       db_rbt_parse_node(r, &rec.key, &rec.value);
+       rec.db = db;
+       rec.private_data = &rec_priv;
+       if (rw) {
+               rec.store = db_rbt_store;
+               rec.delete_rec = db_rbt_delete;
+       } else {
+               rec.store = db_rbt_store_deny;
+               rec.delete_rec = db_rbt_delete_deny;
+       }
+       db_rbt_parse_node(rec_priv.node, &rec.key, &rec.value);
 
        ret = f(&rec, private_data);
        (*count) ++;
@@ -374,7 +405,15 @@ static int db_rbt_traverse_internal(struct rb_node *n,
                return ret;
        }
 
-       return db_rbt_traverse_internal(n->rb_right, f, private_data, count);
+       if (rec_priv.node != NULL) {
+               /*
+                * If the current record is still there
+                * we should take the current rb_right.
+                */
+               rb_right = rec_priv.node->rb_node.rb_right;
+       }
+
+       return db_rbt_traverse_internal(db, rb_right, f, private_data, count, rw);
 }
 
 static int db_rbt_traverse(struct db_context *db,
@@ -386,7 +425,30 @@ static int db_rbt_traverse(struct db_context *db,
                db->private_data, struct db_rbt_ctx);
        uint32_t count = 0;
 
-       int ret =  db_rbt_traverse_internal(ctx->tree.rb_node, f, private_data, &count);
+       int ret = db_rbt_traverse_internal(db, ctx->tree.rb_node,
+                                          f, private_data, &count,
+                                          true /* rw */);
+       if (ret != 0) {
+               return -1;
+       }
+       if (count > INT_MAX) {
+               return -1;
+       }
+       return count;
+}
+
+static int db_rbt_traverse_read(struct db_context *db,
+                               int (*f)(struct db_record *db,
+                                        void *private_data),
+                               void *private_data)
+{
+       struct db_rbt_ctx *ctx = talloc_get_type_abort(
+               db->private_data, struct db_rbt_ctx);
+       uint32_t count = 0;
+
+       int ret = db_rbt_traverse_internal(db, ctx->tree.rb_node,
+                                          f, private_data, &count,
+                                          false /* rw */);
        if (ret != 0) {
                return -1;
        }
@@ -435,7 +497,7 @@ struct db_context *db_open_rbt(TALLOC_CTX *mem_ctx)
        result->fetch_locked = db_rbt_fetch_locked;
        result->try_fetch_locked = NULL;
        result->traverse = db_rbt_traverse;
-       result->traverse_read = db_rbt_traverse;
+       result->traverse_read = db_rbt_traverse_read;
        result->get_seqnum = db_rbt_get_seqnum;
        result->transaction_start = db_rbt_trans_dummy;
        result->transaction_commit = db_rbt_trans_dummy;