+#include "db.h"
+
+#include <string>
+
+using namespace std;
+
+DB::DB(const char *filename)
+{
+ int ret = sqlite3_open(filename, &db);
+ if (ret != SQLITE_OK) {
+ fprintf(stderr, "%s: %s\n", filename, sqlite3_errmsg(db));
+ exit(1);
+ }
+
+ sqlite3_exec(db, R"(
+ CREATE TABLE IF NOT EXISTS state (state BLOB);
+ )", nullptr, nullptr, nullptr); // Ignore errors.
+}
+
+StateProto DB::get_state()
+{
+ StateProto state;
+
+ sqlite3_stmt *stmt;
+ int ret = sqlite3_prepare(db, "SELECT state FROM state", -1, &stmt, 0);
+ if (ret != SQLITE_OK) {
+ fprintf(stderr, "SELECT prepare: %s\n", sqlite3_errmsg(db));
+ exit(1);
+ }
+
+ ret = sqlite3_step(stmt);
+ if (ret == SQLITE_ROW) {
+ bool ok = state.ParseFromArray(sqlite3_column_blob(stmt, 0), sqlite3_column_bytes(stmt, 0));
+ if (!ok) {
+ fprintf(stderr, "State in database is corrupted!\n");
+ exit(1);
+ }
+ } else if (ret != SQLITE_DONE) {
+ fprintf(stderr, "SELECT step: %s\n", sqlite3_errmsg(db));
+ exit(1);
+ }
+
+ ret = sqlite3_finalize(stmt);
+ if (ret != SQLITE_OK) {
+ fprintf(stderr, "SELECT finalize: %s\n", sqlite3_errmsg(db));
+ exit(1);
+ }
+
+ return state;
+}
+
+void DB::store_state(const StateProto &state)
+{
+ string serialized;
+ state.SerializeToString(&serialized);
+
+ int ret = sqlite3_exec(db, "BEGIN", nullptr, nullptr, nullptr);
+ if (ret != SQLITE_OK) {
+ fprintf(stderr, "BEGIN: %s\n", sqlite3_errmsg(db));
+ exit(1);
+ }
+
+ ret = sqlite3_exec(db, "DELETE FROM state", nullptr, nullptr, nullptr);
+ if (ret != SQLITE_OK) {
+ fprintf(stderr, "DELETE: %s\n", sqlite3_errmsg(db));
+ exit(1);
+ }
+
+ sqlite3_stmt *stmt;
+ ret = sqlite3_prepare(db, "INSERT INTO state VALUES (?)", -1, &stmt, 0);
+ if (ret != SQLITE_OK) {
+ fprintf(stderr, "INSERT prepare: %s\n", sqlite3_errmsg(db));
+ exit(1);
+ }
+
+ sqlite3_bind_blob(stmt, 1, serialized.data(), serialized.size(), SQLITE_STATIC);
+
+ ret = sqlite3_step(stmt);
+ if (ret == SQLITE_ROW) {
+ fprintf(stderr, "INSERT step: %s\n", sqlite3_errmsg(db));
+ exit(1);
+ }
+
+ ret = sqlite3_finalize(stmt);
+ if (ret != SQLITE_OK) {
+ fprintf(stderr, "INSERT finalize: %s\n", sqlite3_errmsg(db));
+ exit(1);
+ }
+
+ ret = sqlite3_exec(db, "COMMIT", nullptr, nullptr, nullptr);
+ if (ret != SQLITE_OK) {
+ fprintf(stderr, "COMMIT: %s\n", sqlite3_errmsg(db));
+ exit(1);
+ }
+}