server: Database schema version

2 files changed, 33 insertions, 5 deletions

diff --git a/db.c b/db.c
index 32a8df4..4572ea2 100644
--- a/db.c
+++ b/db.c
@@ -9,6 +9,8 @@
 
 #define SQLITE(func,...) do{if(sqlite3_##func(__VA_ARGS__)!=SQLITE_OK){die_sqlite("sqlite3_" #func);}}while(0)
 
+#define DATABASE_VERSION 1
+
 
 sqlite3 *database=NULL;
 
@@ -21,13 +23,35 @@ static void die_sqlite(const char *func){
 void db_init(void){
 	SQLITE(config,SQLITE_CONFIG_SERIALIZED);
 	SQLITE(initialize);
+
 	SQLITE(open_v2,"db.db",&database,SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE,NULL);
 	SQLITE(busy_timeout,database,500);
-	char *str=malloc(schema_sql_len+1,char);
-	memcpy(str,schema_sql,schema_sql_len);
-	str[schema_sql_len]='\0';
-	sqlite3_exec(database,str,NULL,NULL,NULL);
-	free(str);
+
+	sqlite3_stmt *stmt;
+	int res = sqlite3_prepare_v2(database, "select version from Meta", -1, &stmt, NULL);
+	if (res == SQLITE_OK && sqlite3_step(stmt) == SQLITE_ROW) {
+		i64 version = sqlite3_column_int64(stmt, 0);
+		SQLITE(finalize, stmt);
+
+		if (version != DATABASE_VERSION) {
+			die("Database version incompatible: database %" PRIi64 ", application %d",
+				version, DATABASE_VERSION);
+		}
+	} else {
+		if (res == SQLITE_OK) SQLITE(finalize, stmt);
+
+		char *str=malloc(schema_sql_len+1,char);
+		memcpy(str,schema_sql,schema_sql_len);
+		str[schema_sql_len]='\0';
+		SQLITE(exec,database,str,NULL,NULL,NULL);
+		free(str);
+
+		SQLITE(prepare_v2, database, "insert into Meta (version) values (?)", -1, &stmt, NULL);
+		SQLITE(bind_int64, stmt, 1, DATABASE_VERSION);
+		if (sqlite3_step(stmt) != SQLITE_DONE) {
+			die("Could not set database version: %s", sqlite3_errmsg(database));
+		}
+	}
 }
 
 void db_reinit(void){
diff --git a/schema.sql b/schema.sql
index 6291102..55fe091 100644
--- a/schema.sql
+++ b/schema.sql
@@ -1,5 +1,9 @@
 pragma foreign_keys = on;
 
+create table Meta (
+	version integer
+);
+
 create table Rooms (
 	id integer primary key,
 	name text