--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/core/save.c	Sat Mar 07 17:06:01 2020 +0100
@@ -0,0 +1,214 @@
+/*
+ * save.c -- save functions
+ *
+ * Copyright (c) 2020 David Demelier <markand@malikania.fr>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <assert.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <sqlite3.h>
+
+#include "error.h"
+#include "save.h"
+#include "sys.h"
+
+static sqlite3 *db;
+
+static const char *sinit =
+	"BEGIN EXCLUSIVE TRANSACTION;"
+	""
+	"CREATE TABLE IF NOT EXISTS property("
+	"  id INTEGER PRIMARY KEY AUTOINCREMENT,"
+	"  key TEXT NOT NULL UNIQUE,"
+	"  value TEXT NOT NULL"
+	");"
+	""
+	"COMMIT"
+;
+
+static const char *sbegin =
+	"BEGIN EXCLUSIVE TRANSACTION"
+;
+
+static const char *scommit =
+	"COMMIT"
+;
+
+static const char *srollback =
+	"ROLLBACK"
+;
+
+static const char *sset_property =
+	"INSERT OR REPLACE INTO property("
+	"  key,"
+	"  value"
+	")"
+	"VALUES("
+	"  ?,"
+	"  ?"
+	");"
+;
+
+static const char *sget_property =
+	"SELECT value"
+	"  FROM property"
+	" WHERE key = ?"
+;
+
+static const char *sremove_property =
+	"DELETE"
+	"  FROM property"
+	" WHERE key = ?"
+;
+
+static bool
+exec(const char *sql)
+{
+	if (sqlite3_exec(db, sql, NULL, NULL, NULL) != SQLITE_OK)
+		return error_printf("%s", sqlite3_errmsg(db));
+
+	return true;
+}
+
+bool
+save_open(unsigned int idx)
+{
+	return save_open_path(sys_savepath(idx));
+}
+
+bool
+save_open_path(const char *path)
+{
+	assert(path);
+
+	if (sqlite3_open(path, &db) != SQLITE_OK)
+		return error_printf("database open error: %s", sqlite3_errmsg(db));
+	if (sqlite3_exec(db, sinit, NULL, NULL, NULL) != SQLITE_OK)
+		return error_printf("database init error: %s", sqlite3_errmsg(db));
+
+	return true;
+}
+
+bool
+save_set_property(const char *key, const char *value)
+{
+	assert(key);
+	assert(value && strlen(value) <= SAVE_PROPERTY_VALUE_MAX);
+
+	sqlite3_stmt *stmt = NULL;
+
+	if (!exec(sbegin))
+		return false;
+	if (sqlite3_prepare(db, sset_property, -1, &stmt, NULL) != SQLITE_OK)
+		goto sqlite3_err;
+	if (sqlite3_bind_text(stmt, 1, key, -1, NULL) != SQLITE_OK ||
+	    sqlite3_bind_text(stmt, 2, value, -1, NULL) != SQLITE_OK)
+		goto sqlite3_err;
+	if (sqlite3_step(stmt) != SQLITE_DONE)
+		goto sqlite3_err;
+
+	sqlite3_finalize(stmt);
+
+	return exec(scommit);
+
+sqlite3_err:
+	if (stmt) {
+		sqlite3_finalize(stmt);
+		exec(srollback);
+	}
+
+	return error_printf("%s", sqlite3_errmsg(db));
+}
+
+const char *
+save_get_property(const char *key)
+{
+	assert(key);
+
+	static char value[SAVE_PROPERTY_VALUE_MAX + 1];
+	const char *ret = value;
+	sqlite3_stmt *stmt = NULL;
+
+	memset(value, 0, sizeof (value));
+
+	if (sqlite3_prepare(db, sget_property, -1, &stmt, NULL) != SQLITE_OK)
+		goto sqlite3_err;
+	if (sqlite3_bind_text(stmt, 1, key, -1, NULL) != SQLITE_OK)
+		goto sqlite3_err;
+
+	switch (sqlite3_step(stmt)) {
+	case SQLITE_DONE:
+		/* Not found. */
+		ret = NULL;
+		break;
+	case SQLITE_ROW:
+		/* Found. */
+		snprintf(value, sizeof (value), "%s", sqlite3_column_text(stmt, 0));
+		break;
+	default:
+		/* Error. */
+		goto sqlite3_err;
+	}
+
+	sqlite3_finalize(stmt);
+
+	return ret;
+
+sqlite3_err:
+	if (stmt)
+		sqlite3_finalize(stmt);
+
+	error_printf("%s", sqlite3_errmsg(db));
+
+	return NULL;
+}
+
+bool
+save_remove_property(const char *key)
+{
+	assert(key);
+
+	sqlite3_stmt *stmt = NULL;
+
+	if (!exec(sbegin))
+		return false;
+	if (sqlite3_prepare(db, sremove_property, -1, &stmt, NULL) != SQLITE_OK)
+		goto sqlite3_err;
+	if (sqlite3_bind_text(stmt, 1, key, -1, NULL) != SQLITE_OK)
+		goto sqlite3_err;
+	if (sqlite3_step(stmt) != SQLITE_DONE)
+		goto sqlite3_err;
+
+	sqlite3_finalize(stmt);
+
+	return exec(scommit);
+
+sqlite3_err:
+	if (stmt)
+		sqlite3_finalize(stmt);
+
+	error_printf("%s", sqlite3_errmsg(db));
+
+	return false;
+}
+
+void
+save_finish(void)
+{
+	if (db)
+		sqlite3_close(db);
+}