Function prepare_table_manip

db/db_sqlite3.c:463–520

Move table out the way, return columns. * Note: with db_hook, frees tmpctx! */

/* Move table out the way, return columns.
 * Note: with db_hook, frees tmpctx! */
static char **prepare_table_manip(const tal_t *ctx,
				  struct db *db, const char *tablename)
{
	sqlite3_stmt *stmt;
	const char *sql;
	char *cmd, *bracket;
	char **parts;
	int err;
	struct db_sqlite3 *wrapper = (struct db_sqlite3 *)db->conn;

	/* Get schema. */
	sqlite3_prepare_v2(wrapper->conn, "SELECT sql FROM sqlite_master WHERE type = ? AND name = ?;", -1, &stmt, NULL);
	sqlite3_bind_text(stmt, 1, "table", strlen("table"), SQLITE_TRANSIENT);
	sqlite3_bind_text(stmt, 2, tablename, strlen(tablename), SQLITE_TRANSIENT);

	err = sqlite3_step(stmt);
	if (err != SQLITE_ROW) {
		db->error = tal_fmt(db, "getting schema: %s",
				    sqlite3_errmsg(wrapper->conn));
		sqlite3_finalize(stmt);
		return NULL;
	}

	sql = tal_strdup(tmpctx, (const char *)sqlite3_column_text(stmt, 0));
	sqlite3_finalize(stmt);

	/* We MUST use generic routines to write to db, since they
	 * mirror changes to the db hook! */
	bracket = strchr(sql, '(');
	if (!strstarts(sql, "CREATE TABLE") || !bracket)
		db_fatal(db, "Bad sql from prepare_table_manip %s: %s",
			 tablename, sql);

	/* Split after ( by commas: any lower case is assumed to be a field */
	parts = tal_strsplit(ctx, bracket + 1, ",", STR_EMPTY_OK);

	/* Now, we actually need to turn OFF transactions for a moment, as
	 * this pragma only has an effect outside a tx! */
	db_commit_transaction(db);

	/* But core insists we're "in a transaction" for all ops, so fake it */
	db->in_transaction = "Not really";
	db->transaction_started = true;
	/* Turn off foreign keys first. */
	db_prepare_for_changes(db);
	db_exec_prepared_v2(take(db_prepare_untranslated(db,
							 "PRAGMA foreign_keys = OFF;")));
	db_report_changes(db, NULL, 0);
	db->in_transaction = NULL;
	db->transaction_started = false;

	db_begin_transaction(db);
	cmd = tal_fmt(tmpctx, "ALTER TABLE %s RENAME TO temp_%s;",
		      tablename, tablename);
	db_exec_prepared_v2(take(db_prepare_untranslated(db, cmd)));

	return parts;
}