db: add version field.

We can get weird errors when we try to load a database of a different
from.  Just slap a git version in there for now.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

daemon/db.c

@@ -2,6 +2,7 @@
 #include "commit_tx.h"
 #include "db.h"
 #include "feechange.h"
+#include "gen_version.h"
 #include "htlc.h"
 #include "invoice.h"
 #include "lightningd.h"
@@ -1149,8 +1150,38 @@ static void db_load_addresses(struct lightningd_state *dstate)
 	tal_free(ctx);
 }
 
+static void db_check_version(struct lightningd_state *dstate)
+{
+	int err;
+	sqlite3_stmt *stmt;
+	sqlite3 *sql = dstate->db->sql;
+	char *ctx = tal_tmpctx(dstate);
+	const char *select;
+
+	select = tal_fmt(ctx, "SELECT * FROM version;");
+
+	err = sqlite3_prepare_v2(sql, select, -1, &stmt, NULL);
+	if (err != SQLITE_OK)
+		fatal("DATABASE NEEDS UPDATE.  Can't access VERSION: %s:%s",
+		      sqlite3_errstr(err), sqlite3_errmsg(sql));
+
+	while ((err = sqlite3_step(stmt)) != SQLITE_DONE) {
+		const char *ver;
+
+		if (err != SQLITE_ROW)
+			fatal("db_check_version:step gave %s:%s",
+			      sqlite3_errstr(err), sqlite3_errmsg(sql));
+		ver = sqlite3_column_str(stmt, 0);
+		if (!streq(ver, VERSION))
+			fatal("DATABASE NEEDS UPDATE. Version %s does not match %s",
+			      ver, VERSION);
+	}
+	tal_free(ctx);
+}
+
 static void db_load(struct lightningd_state *dstate)
 {
+	db_check_version(dstate);
 	db_load_wallet(dstate);
 	db_load_addresses(dstate);
 	db_load_peers(dstate);
@@ -1194,7 +1225,9 @@ void db_init(struct lightningd_state *dstate)
 	}
 
 	/* Set up tables. */
-	if (!db_exec(__func__, dstate,
+	dstate->db->in_transaction = true;
+	db_exec(__func__, dstate, "BEGIN IMMEDIATE;");
+	db_exec(__func__, dstate,
 		TABLE(wallet,
 		      SQL_PRIVKEY(privkey))
 		TABLE(pay,
@@ -1261,7 +1294,13 @@ void db_init(struct lightningd_state *dstate)
 		TABLE(peers,
 		      SQL_PUBKEY(peer), SQL_STATENAME(state),
 		      SQL_BOOL(offered_anchor), SQL_U32(our_feerate),
-			   "PRIMARY KEY(peer)"))) {
+		      "PRIMARY KEY(peer)")
+		TABLE(version, "version VARCHAR(100)"));
+	db_exec(__func__, dstate, "INSERT INTO version VALUES ('"VERSION"');");
+	db_exec(__func__, dstate, "COMMIT;");
+	dstate->db->in_transaction = false;
+
+	if (dstate->db->err) {
 		unlink(DB_FILE);
 		fatal("%s", dstate->db->err);
 	}