sqlite3: Move begin transaction and commit into the driver

This has a slight side-effect of removing the actual begin and commit
statements from the `db_write` hooks, but they are mostly redundant anyway (no
harm in grouping pre-init statements into one transaction, and we know that
each post-init call is supposed to be wrapped anyway).

Signed-off-by: Christian Decker <decker.christian@gmail.com>

tests/plugins/dblog.py

@@ -16,9 +16,18 @@ def init(configuration, options, plugin):
     plugin.conn = sqlite3.connect(plugin.get_option('dblog-file'),
                                   isolation_level=None)
     plugin.log("replaying pre-init data:")
+    plugin.conn.execute("PRAGMA foreign_keys = ON;")
+
+    print(plugin.sqlite_pre_init_cmds)
+
+    plugin.conn.execute("BEGIN TRANSACTION;")
+
     for c in plugin.sqlite_pre_init_cmds:
         plugin.conn.execute(c)
         plugin.log("{}".format(c))
+
+    plugin.conn.execute("COMMIT;")
+
     plugin.initted = True
     plugin.log("initialized {}".format(configuration))
 
@@ -29,9 +38,15 @@ def db_write(plugin, writes, **kwargs):
         plugin.log("deferring {} commands".format(len(writes)))
         plugin.sqlite_pre_init_cmds += writes
     else:
+        print(writes)
+        plugin.conn.execute("BEGIN TRANSACTION;")
+
         for c in writes:
             plugin.conn.execute(c)
             plugin.log("{}".format(c))
+
+        plugin.conn.execute("COMMIT;")
+
     return True
 
 

wallet/db.c

@@ -789,30 +789,29 @@ size_t db_changes(struct db *db)
 
 void db_begin_transaction_(struct db *db, const char *location)
 {
+	bool ok;
 	if (db->in_transaction)
 		db_fatal("Already in transaction from %s", db->in_transaction);
 
 	db_prepare_for_changes(db);
-	db_do_exec(location, db, "BEGIN TRANSACTION;");
+	ok = db->config->begin_tx_fn(db);
+	if (!ok)
+		db_fatal("Failed to start DB transaction: %s", db->error);
+
 	db->in_transaction = location;
 }
 
 void db_commit_transaction(struct db *db)
 {
-	int err;
-	char *errmsg;
-	const char *cmd = "COMMIT;";
-
+	bool ok;
 	assert(db->in_transaction);
 	db_assert_no_outstanding_statements();
+	ok = db->config->commit_tx_fn(db);
 
-	/* We expect at least the BEGIN TRANSACTION */
-	db_report_changes(db, cmd, 1);
-
-	err = sqlite3_exec(db->sql, cmd, NULL, NULL, &errmsg);
-	if (err != SQLITE_OK)
-		db_fatal("%s:%s:%s:%s", __func__, sqlite3_errstr(err), cmd, errmsg);
+	if (!ok)
+		db_fatal("Failed to commit DB transaction: %s", db->error);
 
+	db_report_changes(db, NULL, 0);
 	db->in_transaction = NULL;
 }
 

wallet/test/run-wallet.c

@@ -1138,6 +1138,9 @@ static bool test_htlc_crud(struct lightningd *ld, const tal_t *ctx)
 	/* Make sure we have our references correct */
 	CHECK(transaction_wrap(w->db,
 			       db_exec(__func__, w->db, "INSERT INTO channels (id) VALUES (1);")));
+	db_begin_transaction(w->db);
+	db_commit_transaction(w->db);
+
 	chan->dbid = 1;
 	chan->peer = peer;