--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/util/sqlite3.lua	Mon Aug 01 15:23:33 2022 +0200
@@ -0,0 +1,390 @@
+
+-- luacheck: ignore 113/unpack 211 212 411 213
+local setmetatable, getmetatable = setmetatable, getmetatable;
+local ipairs, unpack, select = ipairs, table.unpack or unpack, select;
+local tonumber, tostring = tonumber, tostring;
+local assert, xpcall, debug_traceback = assert, xpcall, debug.traceback;
+local error = error
+local type = type
+local t_concat = table.concat;
+local t_insert = table.insert;
+local s_char = string.char;
+local log = require "util.logger".init("sql");
+
+local lsqlite3 = require "lsqlite3";
+local build_url = require "socket.url".build;
+local ROW, DONE = lsqlite3.ROW, lsqlite3.DONE;
+local err2str = {
+	[0] = "OK";
+	"ERROR";
+	"INTERNAL";
+	"PERM";
+	"ABORT";
+	"BUSY";
+	"LOCKED";
+	"NOMEM";
+	"READONLY";
+	"INTERRUPT";
+	"IOERR";
+	"CORRUPT";
+	"NOTFOUND";
+	"FULL";
+	"CANTOPEN";
+	"PROTOCOL";
+	"EMPTY";
+	"SCHEMA";
+	"TOOBIG";
+	"CONSTRAINT";
+	"MISMATCH";
+	"MISUSE";
+	"NOLFS";
+	[24] = "FORMAT";
+	[25] = "RANGE";
+	[26] = "NOTADB";
+	[100] = "ROW";
+	[101] = "DONE";
+};
+
+local assert = function(cond, errno, err)
+	return assert(cond, err or err2str[errno]);
+end
+local _ENV = nil;
+-- luacheck: std none
+
+local column_mt = {};
+local table_mt = {};
+local query_mt = {};
+--local op_mt = {};
+local index_mt = {};
+
+local function is_column(x) return getmetatable(x)==column_mt; end
+local function is_index(x) return getmetatable(x)==index_mt; end
+local function is_table(x) return getmetatable(x)==table_mt; end
+local function is_query(x) return getmetatable(x)==query_mt; end
+local function Integer(n) return "Integer()" end
+local function String(n) return "String()" end
+
+local function Column(definition)
+	return setmetatable(definition, column_mt);
+end
+local function Table(definition)
+	local c = {}
+	for i,col in ipairs(definition) do
+		if is_column(col) then
+			c[i], c[col.name] = col, col;
+		elseif is_index(col) then
+			col.table = definition.name;
+		end
+	end
+	return setmetatable({ __table__ = definition, c = c, name = definition.name }, table_mt);
+end
+local function Index(definition)
+	return setmetatable(definition, index_mt);
+end
+
+function table_mt:__tostring()
+	local s = { 'name="'..self.__table__.name..'"' }
+	for i,col in ipairs(self.__table__) do
+		s[#s+1] = tostring(col);
+	end
+	return 'Table{ '..t_concat(s, ", ")..' }'
+end
+table_mt.__index = {};
+function table_mt.__index:create(engine)
+	return engine:_create_table(self);
+end
+function table_mt:__call(...)
+	-- TODO
+end
+function column_mt:__tostring()
+	return 'Column{ name="'..self.name..'", type="'..self.type..'" }'
+end
+function index_mt:__tostring()
+	local s = 'Index{ name="'..self.name..'"';
+	for i=1,#self do s = s..', "'..self[i]:gsub("[\\\"]", "\\%1")..'"'; end
+	return s..' }';
+--	return 'Index{ name="'..self.name..'", type="'..self.type..'" }'
+end
+
+local function urldecode(s) return s and (s:gsub("%%(%x%x)", function (c) return s_char(tonumber(c,16)); end)); end
+local function parse_url(url)
+	local scheme, secondpart, database = url:match("^([%w%+]+)://([^/]*)/?(.*)");
+	assert(scheme, "Invalid URL format");
+	local username, password, host, port;
+	local authpart, hostpart = secondpart:match("([^@]+)@([^@+])");
+	if not authpart then hostpart = secondpart; end
+	if authpart then
+		username, password = authpart:match("([^:]*):(.*)");
+		username = username or authpart;
+		password = password and urldecode(password);
+	end
+	if hostpart then
+		host, port = hostpart:match("([^:]*):(.*)");
+		host = host or hostpart;
+		port = port and assert(tonumber(port), "Invalid URL format");
+	end
+	return {
+		scheme = scheme:lower();
+		username = username; password = password;
+		host = host; port = port;
+		database = #database > 0 and database or nil;
+	};
+end
+
+local engine = {};
+function engine:connect()
+	if self.conn then return true; end
+
+	local params = self.params;
+	assert(params.driver == "SQLite3", "Only sqlite3 is supported");
+	local dbh, err = lsqlite3.open(params.database);
+	if not dbh then return nil, err2str[err]; end
+	self.conn = dbh;
+	self.prepared = {};
+	local ok, err = self:set_encoding();
+	if not ok then
+		return ok, err;
+	end
+	local ok, err = self:onconnect();
+	if ok == false then
+		return ok, err;
+	end
+	return true;
+end
+function engine:onconnect()
+	-- Override from create_engine()
+end
+function engine:execute(sql, ...)
+	local success, err = self:connect();
+	if not success then return success, err; end
+	local prepared = self.prepared;
+
+	local stmt = prepared[sql];
+	if not stmt then
+		local err;
+		stmt, err = self.conn:prepare(sql);
+		if not stmt then return stmt, err; end
+		prepared[sql] = stmt;
+	end
+
+	local ret = stmt:bind_values(...);
+	if ret ~= lsqlite3.OK then return nil, self.conn:errmsg(); end
+	return stmt;
+end
+
+local result_mt = {
+	__index = {
+	affected = function(self) return self.__affected; end;
+	rowcount = function(self) return self.__rowcount; end;
+	},
+};
+
+local function iterator(table)
+	local i=0;
+	return function()
+		i=i+1;
+		local item=table[i];
+		if item ~= nil then
+			return item;
+		end
+	end
+end
+
+local function debugquery(where, sql, ...)
+	local i = 0; local a = {...}
+	sql = sql:gsub("\n?\t+", " ");
+	log("debug", "[%s] %s", where, (sql:gsub("%?", function ()
+		i = i + 1;
+		local v = a[i];
+		if type(v) == "string" then
+			v = ("'%s'"):format(v:gsub("'", "''"));
+		end
+		return tostring(v);
+	end)));
+end
+
+function engine:execute_query(sql, ...)
+	local prepared = self.prepared;
+	local stmt = prepared[sql];
+	if stmt and stmt:isopen() then
+		prepared[sql] = nil; -- Can't be used concurrently
+	else
+		stmt = assert(self.conn:prepare(sql));
+	end
+	local ret = stmt:bind_values(...);
+	if ret ~= lsqlite3.OK then error(self.conn:errmsg()); end
+	local data, ret = {}
+	while stmt:step() == ROW do
+		t_insert(data, stmt:get_values());
+	end
+	-- FIXME Error handling, BUSY, ERROR, MISUSE
+	if stmt:reset() == lsqlite3.OK then
+		prepared[sql] = stmt;
+	end
+	return setmetatable({ __data = data }, { __index = result_mt.__index, __call = iterator(data) });
+end
+function engine:execute_update(sql, ...)
+	local prepared = self.prepared;
+	local stmt = prepared[sql];
+	if not stmt or not stmt:isopen() then
+		stmt = assert(self.conn:prepare(sql));
+	else
+		prepared[sql] = nil;
+	end
+	local ret = stmt:bind_values(...);
+	if ret ~= lsqlite3.OK then error(self.conn:errmsg()); end
+	local rowcount = 0;
+	repeat
+		ret = stmt:step();
+		if ret == lsqlite3.ROW then
+			rowcount = rowcount + 1;
+		end
+	until ret ~= lsqlite3.ROW;
+	local affected = self.conn:changes();
+	if stmt:reset() == lsqlite3.OK then
+		prepared[sql] = stmt;
+	end
+	return setmetatable({ __affected = affected, __rowcount = rowcount }, result_mt);
+end
+engine.insert = engine.execute_update;
+engine.select = engine.execute_query;
+engine.delete = engine.execute_update;
+engine.update = engine.execute_update;
+local function debugwrap(name, f)
+	return function (self, sql, ...)
+		debugquery(name, sql, ...)
+		return f(self, sql, ...)
+	end
+end
+function engine:debug(enable)
+	self._debug = enable;
+	if enable then
+		engine.insert = debugwrap("insert", engine.execute_update);
+		engine.select = debugwrap("select", engine.execute_query);
+		engine.delete = debugwrap("delete", engine.execute_update);
+		engine.update = debugwrap("update", engine.execute_update);
+	else
+		engine.insert = engine.execute_update;
+		engine.select = engine.execute_query;
+		engine.delete = engine.execute_update;
+		engine.update = engine.execute_update;
+	end
+end
+function engine:_(word)
+	local ret = self.conn:exec(word);
+	if ret ~= lsqlite3.OK then return nil, self.conn:errmsg(); end
+	return true;
+end
+function engine:_transaction(func, ...)
+	if not self.conn then
+		local a,b = self:connect();
+		if not a then return a,b; end
+	end
+	--assert(not self.__transaction, "Recursive transactions not allowed");
+	local ok, err = self:_"BEGIN";
+	if not ok then return ok, err; end
+	self.__transaction = true;
+	local success, a, b, c = xpcall(func, debug_traceback, ...);
+	self.__transaction = nil;
+	if success then
+		log("debug", "SQL transaction success [%s]", tostring(func));
+		local ok, err = self:_"COMMIT";
+		if not ok then return ok, err; end -- commit failed
+		return success, a, b, c;
+	else
+		log("debug", "SQL transaction failure [%s]: %s", tostring(func), a);
+		if self.conn then self:_"ROLLBACK"; end
+		return success, a;
+	end
+end
+function engine:transaction(...)
+	local ok, ret = self:_transaction(...);
+	if not ok then
+		local conn = self.conn;
+		if not conn or not conn:isopen() then
+			self.conn = nil;
+			ok, ret = self:_transaction(...);
+		end
+	end
+	return ok, ret;
+end
+function engine:_create_index(index)
+	local sql = "CREATE INDEX IF NOT EXISTS \""..index.name.."\" ON \""..index.table.."\" (";
+	for i=1,#index do
+		sql = sql.."\""..index[i].."\"";
+		if i ~= #index then sql = sql..", "; end
+	end
+	sql = sql..");"
+	if index.unique then
+		sql = sql:gsub("^CREATE", "CREATE UNIQUE");
+	end
+	if self._debug then
+		debugquery("create", sql);
+	end
+	return self:execute(sql);
+end
+function engine:_create_table(table)
+	local sql = "CREATE TABLE IF NOT EXISTS \""..table.name.."\" (";
+	for i,col in ipairs(table.c) do
+		local col_type = col.type;
+		sql = sql.."\""..col.name.."\" "..col_type;
+		if col.nullable == false then sql = sql.." NOT NULL"; end
+		if col.primary_key == true then sql = sql.." PRIMARY KEY"; end
+		if col.auto_increment == true then
+			sql = sql.." AUTOINCREMENT";
+		end
+		if i ~= #table.c then sql = sql..", "; end
+	end
+	sql = sql.. ");"
+	if self._debug then
+		debugquery("create", sql);
+	end
+	local success,err = self:execute(sql);
+	if not success then return success,err; end
+	for i,v in ipairs(table.__table__) do
+		if is_index(v) then
+			self:_create_index(v);
+		end
+	end
+	return success;
+end
+function engine:set_encoding() -- to UTF-8
+	return self:transaction(function()
+			for encoding in self:select"PRAGMA encoding;" do
+				if encoding[1] == "UTF-8" then
+				self.charset = "utf8";
+			end
+		end
+	end);
+end
+local engine_mt = { __index = engine };
+
+local function db2uri(params)
+	return build_url{
+		scheme = params.driver,
+		user = params.username,
+		password = params.password,
+		host = params.host,
+		port = params.port,
+		path = params.database,
+	};
+end
+
+local function create_engine(_, params, onconnect)
+	assert(params.driver == "SQLite3", "Only SQLite3 is supported without LuaDBI");
+	return setmetatable({ url = db2uri(params), params = params, onconnect = onconnect }, engine_mt);
+end
+
+return {
+	is_column = is_column;
+	is_index = is_index;
+	is_table = is_table;
+	is_query = is_query;
+	Integer = Integer;
+	String = String;
+	Column = Column;
+	Table = Table;
+	Index = Index;
+	create_engine = create_engine;
+	db2uri = db2uri;
+};