diff --git a/src/Pure/General/sql.scala b/src/Pure/General/sql.scala --- a/src/Pure/General/sql.scala +++ b/src/Pure/General/sql.scala @@ -1,896 +1,897 @@ /* Title: Pure/General/sql.scala Author: Makarius Support for SQL databases: SQLite and PostgreSQL. See https://docs.oracle.com/en/java/javase/21/docs/api/java.sql/java/sql/Connection.html */ package isabelle import java.time.OffsetDateTime import java.sql.{DriverManager, Connection, PreparedStatement, ResultSet, SQLException} import org.sqlite.SQLiteConfig import org.sqlite.jdbc4.JDBC4Connection import org.postgresql.PGConnection import scala.collection.mutable object SQL { lazy val time_start = Time.now() /** SQL language **/ type Source = String /* concrete syntax */ def string(s: String): Source = { val q = '\'' val result = new StringBuilder(s.length + 10) result += q for (c <- s.iterator) { if (c == '\u0000') error("Illegal NUL character in SQL string literal") if (c == q) result += q result += c } result += q result.toString } def ident(s: String): Source = Long_Name.implode(Long_Name.explode(s).map(a => quote(a.replace("\"", "\"\"")))) def enclose(s: Source): Source = "(" + s + ")" def enclosure(ss: Iterable[Source]): Source = ss.mkString("(", ", ", ")") def separate(sql: Source): Source = if_proper(sql.nonEmpty && sql(0) != ' ', " ") + sql def select(columns: List[Column] = Nil, distinct: Boolean = false, sql: Source = ""): Source = "SELECT " + if_proper(distinct, "DISTINCT ") + (if (columns.isEmpty) "*" else commas(columns.map(_.ident))) + " FROM " + sql val join_outer: Source = " LEFT OUTER JOIN " val join_inner: Source = " INNER JOIN " def MULTI(args: Iterable[Source]): Source = args.iterator.filter(_.nonEmpty).mkString(";\n") def multi(args: Source*): Source = MULTI(args) def infix(op: Source, args: Iterable[Source]): Source = { val body = args.iterator.filter(_.nonEmpty).mkString(" " + op + " ") if_proper(body, enclose(body)) } def AND(args: Iterable[Source]): Source = infix("AND", args) def OR(args: Iterable[Source]): Source = infix("OR", args) def and(args: Source*): Source = AND(args) def or(args: Source*): Source = OR(args) val TRUE: Source = "TRUE" val FALSE: Source = "FALSE" def equal(sql: Source, x: Int): Source = sql + " = " + x def equal(sql: Source, x: Long): Source = sql + " = " + x def equal(sql: Source, x: String): Source = sql + " = " + string(x) def member_int(sql: Source, set: Iterable[Int]): Source = if (set.isEmpty) FALSE else OR(set.iterator.map(equal(sql, _)).toList) def member_long(sql: Source, set: Iterable[Long]): Source = if (set.isEmpty) FALSE else OR(set.iterator.map(equal(sql, _)).toList) def member(sql: Source, set: Iterable[String]): Source = if (set.isEmpty) FALSE else OR(set.iterator.map(equal(sql, _)).toList) def where(sql: Source): Source = if_proper(sql, " WHERE " + sql) def where_and(args: Source*): Source = where(and(args:_*)) def where_or(args: Source*): Source = where(or(args:_*)) /* types */ enum Type { case Boolean, Int, Long, Double, String, Bytes, Date } val sql_type_postgresql: Type => Source = { case Type.Boolean => "BOOLEAN" case Type.Int => "INTEGER" case Type.Long => "BIGINT" case Type.Double => "DOUBLE PRECISION" case Type.String => "TEXT" case Type.Bytes => "BYTEA" case Type.Date => "TIMESTAMP WITH TIME ZONE" } val sql_type_sqlite: Type => Source = { case Type.Boolean => "INTEGER" case Type.Bytes => "BLOB" case Type.Date => "TEXT" case t => sql_type_postgresql(t) } /* columns */ object Column { def bool(name: String, strict: Boolean = false, primary_key: Boolean = false): Column = Column(name, Type.Boolean, strict, primary_key) def int(name: String, strict: Boolean = false, primary_key: Boolean = false): Column = Column(name, Type.Int, strict, primary_key) def long(name: String, strict: Boolean = false, primary_key: Boolean = false): Column = Column(name, Type.Long, strict, primary_key) def double(name: String, strict: Boolean = false, primary_key: Boolean = false): Column = Column(name, Type.Double, strict, primary_key) def string(name: String, strict: Boolean = false, primary_key: Boolean = false): Column = Column(name, Type.String, strict, primary_key) def bytes(name: String, strict: Boolean = false, primary_key: Boolean = false): Column = Column(name, Type.Bytes, strict, primary_key) def date(name: String, strict: Boolean = false, primary_key: Boolean = false): Column = Column(name, Type.Date, strict, primary_key) } sealed case class Column( name: String, T: Type, strict: Boolean = false, primary_key: Boolean = false, expr: SQL.Source = "" ) { def equals_name(other: Column): Boolean = name == other.name def make_primary_key: Column = copy(primary_key = true) def apply(table: Table): Column = Column(Long_Name.qualify(table.name, name), T, strict = strict, primary_key = primary_key) def ident: Source = if_proper(expr, enclose(expr) + " AS ") + SQL.ident(name) def decl(sql_type: Type => Source): Source = ident + " " + sql_type(T) + if_proper(strict || primary_key, " NOT NULL") def defined: String = ident + " IS NOT NULL" def undefined: String = ident + " IS NULL" def equal(x: Int): Source = SQL.equal(ident, x) def equal(x: Long): Source = SQL.equal(ident, x) def equal(x: String): Source = SQL.equal(ident, x) def where_equal(x: Int): Source = SQL.where(equal(x)) def where_equal(x: Long): Source = SQL.where(equal(x)) def where_equal(x: String): Source = SQL.where(equal(x)) def member_int(set: Iterable[Int]): Source = SQL.member_int(ident, set) def member_long(set: Iterable[Long]): Source = SQL.member_long(ident, set) def member(set: Iterable[String]): Source = SQL.member(ident, set) def where_member_int(set: Iterable[Int]): Source = SQL.where(member_int(set)) def where_member_long(set: Iterable[Long]): Source = SQL.where(member_long(set)) def where_member(set: Iterable[String]): Source = SQL.where(member(set)) def make_expr(e: SQL.Source): Column = copy(expr = e) def max: Column = make_expr("MAX(" + ident + ")") override def toString: Source = ident } def order_by(columns: List[Column], descending: Boolean = false): Source = " ORDER BY " + columns.mkString(", ") + if_proper(descending, " DESC") /* tables */ sealed case class Table(name: String, columns: List[Column], body: Source = "") { Library.duplicates(columns.map(_.name)) match { case Nil => case bad => error("Duplicate column names " + commas_quote(bad) + " for table " + quote(name)) } def ident: Source = SQL.ident(name) def query: Source = if (body == "") error("Missing SQL body for table " + quote(name)) else SQL.enclose(body) def query_named: Source = query + " AS " + SQL.ident(name) def create(sql_type: Type => Source): Source = { val primary_key = columns.filter(_.primary_key).map(_.name) match { case Nil => Nil case keys => List("PRIMARY KEY " + enclosure(keys)) } "CREATE TABLE " + ident + " " + enclosure(columns.map(_.decl(sql_type)) ::: primary_key) } def insert_cmd(cmd: Source = "INSERT", sql: Source = ""): Source = cmd + " INTO " + ident + " VALUES " + enclosure(columns.map(_ => "?")) + SQL.separate(sql) def insert(sql: Source = ""): Source = insert_cmd(sql = sql) def delete(sql: Source = ""): Source = "DELETE FROM " + ident + SQL.separate(sql) def update(update_columns: List[Column] = Nil, sql: Source = ""): Source = "UPDATE " + ident + " SET " + commas(update_columns.map(c => c.ident + " = ?")) + SQL.separate(sql) def select( select_columns: List[Column] = Nil, distinct: Boolean = false, sql: Source = "" ): Source = SQL.select(select_columns, distinct = distinct, sql = ident + SQL.separate(sql)) override def toString: Source = ident } /* table groups */ object Tables { def list(list: List[Table]): Tables = new Tables(list) def apply(args: Table*): Tables = list(args.toList) } final class Tables private(val list: List[Table]) extends Iterable[Table] { override def toString: String = list.mkString("SQL.Tables(", ", ", ")") def iterator: Iterator[Table] = list.iterator def index(table: Table): Int = iterator.zipWithIndex .collectFirst({ case (t, i) if t.name == table.name => i }) .getOrElse(error("No table " + quote(table.name))) // requires transaction def lock(db: Database, create: Boolean = false): Boolean = { if (create) foreach(db.create_table(_)) val sql = db.lock_tables(list) if (sql.nonEmpty) { db.execute_statement(sql); true } else false } } /* access data */ def transaction_logger(): Logger = new System_Logger(guard_time = Time.guard_property("isabelle.transaction_trace")) abstract class Data(table_prefix: String = "") { def tables: Tables def transaction_lock[A]( db: Database, create: Boolean = false, label: String = "", log: Logger = transaction_logger() )(body: => A): A = { db.transaction_lock(tables, create = create, label = label, log = log)(body) } def make_table(columns: List[Column], body: String = "", name: String = ""): Table = { val table_name = List(proper_string(table_prefix), proper_string(name)).flatten.mkString("_") require(table_name.nonEmpty, "Undefined database table name") Table(table_name, columns, body = body) } } /** SQL database operations **/ /* statements */ class Batch_Error(val results: List[Int]) extends SQLException class Statement private[SQL](val db: Database, val rep: PreparedStatement) extends AutoCloseable { stmt => object bool { def update(i: Int, x: Boolean): Unit = rep.setBoolean(i, x) def update(i: Int, x: Option[Boolean]): Unit = { if (x.isDefined) update(i, x.get) else rep.setNull(i, java.sql.Types.BOOLEAN) } } object int { def update(i: Int, x: Int): Unit = rep.setInt(i, x) def update(i: Int, x: Option[Int]): Unit = { if (x.isDefined) update(i, x.get) else rep.setNull(i, java.sql.Types.INTEGER) } } object long { def update(i: Int, x: Long): Unit = rep.setLong(i, x) def update(i: Int, x: Option[Long]): Unit = { if (x.isDefined) update(i, x.get) else rep.setNull(i, java.sql.Types.BIGINT) } } object double { def update(i: Int, x: Double): Unit = rep.setDouble(i, x) def update(i: Int, x: Option[Double]): Unit = { if (x.isDefined) update(i, x.get) else rep.setNull(i, java.sql.Types.DOUBLE) } } object string { def update(i: Int, x: String): Unit = rep.setString(i, x) def update(i: Int, x: Option[String]): Unit = update(i, x.orNull) } object bytes { def update(i: Int, bytes: Bytes): Unit = { if (bytes == null) rep.setBytes(i, null) else rep.setBinaryStream(i, bytes.stream(), bytes.length) } def update(i: Int, bytes: Option[Bytes]): Unit = update(i, bytes.orNull) } object date { def update(i: Int, date: Date): Unit = db.update_date(stmt, i, date) def update(i: Int, date: Option[Date]): Unit = update(i, date.orNull) } def execute(): Boolean = rep.execute() def execute_batch(batch: IterableOnce[Statement => Unit]): Unit = { val it = batch.iterator if (it.nonEmpty) { for (body <- it) { body(this); rep.addBatch() } val res = rep.executeBatch() if (!res.forall(i => i >= 0 || i == java.sql.Statement.SUCCESS_NO_INFO)) { throw new Batch_Error(res.toList) } } } def execute_query(): Result = new Result(this, rep.executeQuery()) override def close(): Unit = rep.close() } /* results */ class Result private[SQL](val stmt: Statement, val rep: ResultSet) extends AutoCloseable { res => def next(): Boolean = rep.next() def iterator[A](get: Result => A): Iterator[A] = new Iterator[A] { private var _next: Boolean = res.next() def hasNext: Boolean = _next def next(): A = { val x = get(res); _next = res.next(); x } } def bool(column: Column): Boolean = rep.getBoolean(column.name) def int(column: Column): Int = rep.getInt(column.name) def long(column: Column): Long = rep.getLong(column.name) def double(column: Column): Double = rep.getDouble(column.name) def string(column: Column): String = { val s = rep.getString(column.name) if (s == null) "" else s } def bytes(column: Column): Bytes = { val bs = rep.getBytes(column.name) if (bs == null) Bytes.empty else Bytes(bs) } def date(column: Column): Date = stmt.db.date(res, column) def timing(c1: Column, c2: Column, c3: Column): Timing = Timing(Time.ms(long(c1)), Time.ms(long(c2)), Time.ms(long(c3))) def get[A](column: Column, f: Column => A): Option[A] = { val x = f(column) if (rep.wasNull || x == null) None else Some(x) } def get_bool(column: Column): Option[Boolean] = get(column, bool) def get_int(column: Column): Option[Int] = get(column, int) def get_long(column: Column): Option[Long] = get(column, long) def get_double(column: Column): Option[Double] = get(column, double) def get_string(column: Column): Option[String] = get(column, string) def get_bytes(column: Column): Option[Bytes] = get(column, bytes) def get_date(column: Column): Option[Date] = get(column, date) override def close(): Unit = rep.close() } /* notifications: IPC via database server */ sealed case class Notification(channel: String, payload: String = "") { override def toString: String = "Notification(" + channel + if_proper(payload, "," + payload) + ")" } /* database */ trait Database extends AutoCloseable { db => def is_sqlite: Boolean = isInstanceOf[SQLite.Database] def is_postgresql: Boolean = isInstanceOf[PostgreSQL.Database] def vacuum(tables: List[SQL.Table] = Nil): Unit = if (is_sqlite) execute_statement("VACUUM") // always FULL else if (tables.isEmpty) execute_statement("VACUUM FULL") else if (postgresql_major_version.get <= 10) { for (t <- tables) execute_statement("VACUUM " + t.ident) } else execute_statement("VACUUM" + commas(tables.map(_.ident))) def now(): Date /* types */ def sql_type(T: Type): Source /* connection */ def connection: Connection def sqlite_connection: Option[JDBC4Connection] = connection match { case conn: JDBC4Connection => Some(conn) case _ => None } def postgresql_connection: Option[PGConnection] = connection match { case conn: PGConnection => Some(conn) case _ => None } def the_sqlite_connection: JDBC4Connection = sqlite_connection getOrElse error("SQLite connection expected, but found " + connection.getClass.getName) def the_postgresql_connection: PGConnection = postgresql_connection getOrElse error("PostgreSQL connection expected, but found " + connection.getClass.getName) def postgresql_major_version: Option[Int] = if (is_postgresql) { def err(s: String): Nothing = error("Bad PostgreSQL version " + s) the_postgresql_connection.getParameterStatus("server_version") match { case null => err("null") case str => str.iterator.takeWhile(Symbol.is_ascii_digit).mkString match { case Value.Int(m) => Some(m) case _ => err(quote(str)) } } } else None override def close(): Unit = connection.close() def transaction[A](body: => A): A = connection.synchronized { require(connection.getAutoCommit(), "transaction already active") try { connection.setAutoCommit(false) try { val result = body connection.commit() result } catch { case exn: Throwable => connection.rollback(); throw exn } } finally { connection.setAutoCommit(true) } } def transaction_lock[A]( tables: Tables, create: Boolean = false, label: String = "", log: Logger = transaction_logger() )(body: => A): A = { val trace_count = - SQL.transaction_count() val trace_start = Time.now() var trace_nl = false def trace(msg: String): Unit = { val trace_time = Time.now() - trace_start if (log.guard(trace_time)) { time_start val nl = if (trace_nl) "" else { trace_nl = true; "\nnow = " + (Time.now() - time_start).toString + "\n" } log(nl + trace_time + " transaction " + trace_count + if_proper(label, " " + label) + ": " + msg) } } try { val res = transaction { trace("begin") if (tables.lock(db, create = create)) { trace("locked " + commas_quote(tables.list.map(_.name))) } val res = Exn.capture { body } trace("end") res } trace("commit") Exn.release(res) } catch { case exn: Throwable => trace("crash"); throw exn } } def lock_tables(tables: List[Table]): Source = "" // PostgreSQL only /* statements and results */ def statement(sql: Source): Statement = new Statement(db, connection.prepareStatement(sql)) def using_statement[A](sql: Source)(f: Statement => A): A = using(statement(sql))(f) def execute_statement(sql: Source, body: Statement => Unit = _ => ()): Unit = using_statement(sql) { stmt => body(stmt); stmt.execute() } def execute_batch_statement( sql: Source, batch: IterableOnce[Statement => Unit] = Nil ): Unit = using_statement(sql) { stmt => stmt.execute_batch(batch) } def execute_query_statement[A, B]( sql: Source, make_result: Iterator[A] => B, get: Result => A ): B = { using_statement(sql) { stmt => using(stmt.execute_query()) { res => make_result(res.iterator(get)) } } } def execute_query_statementO[A](sql: Source, get: Result => A): Option[A] = execute_query_statement[A, Option[A]](sql, _.nextOption, get) def execute_query_statementB(sql: Source): Boolean = using_statement(sql)(stmt => using(stmt.execute_query())(_.next())) def update_date(stmt: Statement, i: Int, date: Date): Unit def date(res: Result, column: Column): Date def insert_permissive(table: Table, sql: Source = ""): Source def destroy(table: Table): Source = "DROP TABLE IF EXISTS " + table /* tables and views */ + def name_pattern(name: String): String = { + val escape = connection.getMetaData.getSearchStringEscape + name.iterator.map(c => + if_proper(c == '_' || c == '%' || c == escape(0), escape) + c).mkString + } + def get_tables(pattern: String = "%"): List[String] = { val result = new mutable.ListBuffer[String] val rs = connection.getMetaData.getTables(null, null, pattern, null) while (rs.next) { result += rs.getString(3) } result.toList } - def exists_table(name: String): Boolean = { - val escape = connection.getMetaData.getSearchStringEscape - val pattern = - name.iterator.map(c => - if_proper(c == '_' || c == '%' || c == escape(0), escape) + c).mkString - get_tables(pattern = pattern).nonEmpty - } + def exists_table(name: String): Boolean = + get_tables(pattern = name_pattern(name)).nonEmpty def exists_table(table: Table): Boolean = exists_table(table.name) def create_table(table: Table, sql: Source = ""): Unit = { if (!exists_table(table)) { execute_statement(table.create(sql_type) + SQL.separate(sql)) if (is_postgresql) { for (column <- table.columns if column.T == SQL.Type.Bytes) { execute_statement( "ALTER TABLE " + table + " ALTER COLUMN " + column + " SET STORAGE EXTERNAL") } } } } def create_view(table: Table): Unit = { if (!exists_table(table)) { execute_statement("CREATE VIEW " + table + " AS " + { table.query; table.body }) } } /* notifications (PostgreSQL only) */ def listen(channel: String): Unit = () def unlisten(channel: String = "*"): Unit = () def send(channel: String, payload: String): Unit = () final def send(channel: String): Unit = send(channel, "") final def send(notification: Notification): Unit = send(notification.channel, notification.payload) def receive(filter: Notification => Boolean): Option[List[Notification]] = None } private val transaction_count = Counter.make() } /** SQLite **/ object SQLite { // see https://www.sqlite.org/lang_datefunc.html val date_format: Date.Format = Date.Format("uuuu-MM-dd HH:mm:ss.SSS x") lazy val init_jdbc: Unit = { val lib_path = Path.explode("$ISABELLE_SQLITE_HOME/" + Platform.jvm_platform) val lib_name = File.get_file(lib_path).file_name System.setProperty("org.sqlite.lib.path", File.platform_path(lib_path)) System.setProperty("org.sqlite.lib.name", lib_name) Class.forName("org.sqlite.JDBC") } def open_database(path: Path, restrict: Boolean = false): Database = { init_jdbc val path0 = path.expand val s0 = File.platform_path(path0) val s1 = if (Platform.is_windows) s0.replace('\\', '/') else s0 val config = new SQLiteConfig() config.setEncoding(SQLiteConfig.Encoding.UTF8) val connection = config.createConnection("jdbc:sqlite:" + s1) val db = new Database(path0.toString, connection) try { if (restrict) File.restrict(path0) } catch { case exn: Throwable => db.close(); throw exn } db } class Database private[SQLite](name: String, val connection: Connection) extends SQL.Database { override def toString: String = name override def now(): Date = Date.now() def sql_type(T: SQL.Type): SQL.Source = SQL.sql_type_sqlite(T) def update_date(stmt: SQL.Statement, i: Int, date: Date): Unit = if (date == null) stmt.string(i) = (null: String) else stmt.string(i) = date_format(date) def date(res: SQL.Result, column: SQL.Column): Date = proper_string(res.string(column)) match { case None => null case Some(s) => date_format.parse(s) } def insert_permissive(table: SQL.Table, sql: SQL.Source = ""): SQL.Source = table.insert_cmd(cmd = "INSERT OR IGNORE", sql = sql) } } /** PostgreSQL **/ // see https://www.postgresql.org/docs/14/index.html // see https://jdbc.postgresql.org/documentation object PostgreSQL { type Source = SQL.Source lazy val init_jdbc: Unit = Class.forName("org.postgresql.Driver") val default_server: SSH.Server = SSH.local_server(port = 5432) def open_database( user: String, password: String, database: String = "", server: SSH.Server = default_server, server_close: Boolean = false, receiver_delay: Time = Time.seconds(0.5) ): Database = { init_jdbc if (user.isEmpty) error("Undefined database user") if (server.host.isEmpty) error("Undefined database server host") if (server.port <= 0) error("Undefined database server port") val name = proper_string(database) getOrElse user val url = "jdbc:postgresql://" + server.host + ":" + server.port + "/" + name val ssh = server.ssh_system.ssh_session val print = "server " + quote(user + "@" + server + "/" + name) + if_proper(ssh, " via ssh " + quote(ssh.get.toString)) val connection = DriverManager.getConnection(url, user, password) val db = new Database(connection, print, server, server_close, receiver_delay) try { db.execute_statement("SET standard_conforming_strings = on") } catch { case exn: Throwable => db.close(); throw exn } db } def open_server( options: Options, host: String = "", port: Int = 0, ssh_host: String = "", ssh_port: Int = 0, ssh_user: String = "" ): SSH.Server = { val server_host = proper_string(host).getOrElse(default_server.host) val server_port = if (port > 0) port else default_server.port if (ssh_host.isEmpty) SSH.local_server(host = server_host, port = server_port) else { SSH.open_server(options, host = ssh_host, port = ssh_port, user = ssh_user, remote_host = server_host, remote_port = server_port) } } def open_database_server( options: Options, user: String = "", password: String = "", database: String = "", server: SSH.Server = SSH.no_server, host: String = "", port: Int = 0, ssh_host: String = "", ssh_port: Int = 0, ssh_user: String = "" ): PostgreSQL.Database = { val db_server = if (server.defined) server else { open_server(options, host = host, port = port, ssh_host = ssh_host, ssh_port = ssh_port, ssh_user = ssh_user) } val server_close = !server.defined try { open_database(user = user, password = password, database = database, server = db_server, server_close = server_close) } catch { case exn: Throwable if server_close => db_server.close(); throw exn } } class Database private[PostgreSQL]( val connection: Connection, print: String, server: SSH.Server, server_close: Boolean, receiver_delay: Time ) extends SQL.Database { override def toString: String = print override def now(): Date = { val now = SQL.Column.date("now") execute_query_statementO[Date]("SELECT NOW() as " + now.ident, res => res.date(now)) .getOrElse(error("Failed to get current date/time from database server " + toString)) } def sql_type(T: SQL.Type): SQL.Source = SQL.sql_type_postgresql(T) // see https://jdbc.postgresql.org/documentation/head/8-date-time.html def update_date(stmt: SQL.Statement, i: Int, date: Date): Unit = if (date == null) stmt.rep.setObject(i, null) else stmt.rep.setObject(i, OffsetDateTime.from(date.to(Date.timezone_utc).rep)) def date(res: SQL.Result, column: SQL.Column): Date = { val obj = res.rep.getObject(column.name, classOf[OffsetDateTime]) if (obj == null) null else Date.instant(obj.toInstant) } def insert_permissive(table: SQL.Table, sql: SQL.Source = ""): SQL.Source = table.insert_cmd(sql = if_proper(sql, sql + " ") + "ON CONFLICT DO NOTHING") override def destroy(table: SQL.Table): SQL.Source = super.destroy(table) + " CASCADE" /* explicit locking: only applicable to PostgreSQL within transaction context */ // see https://www.postgresql.org/docs/14/sql-lock.html // see https://www.postgresql.org/docs/14/explicit-locking.html override def lock_tables(tables: List[SQL.Table]): PostgreSQL.Source = if_proper(tables, "LOCK TABLE " + tables.mkString(", ") + " IN ACCESS EXCLUSIVE MODE") /* notifications: IPC via database server */ /* - see https://www.postgresql.org/docs/14/sql-notify.html - self-notifications and repeated notifications are suppressed - notifications are sorted by local system time (nano seconds) - receive() == None means that IPC is inactive or unavailable (SQLite) */ private var _receiver_buffer: Option[Map[SQL.Notification, Long]] = None private lazy val _receiver_thread = Isabelle_Thread.fork(name = "PostgreSQL.receiver", daemon = true, uninterruptible = true) { val conn = the_postgresql_connection val self_pid = conn.getBackendPID try { while (true) { Isabelle_Thread.interruptible { receiver_delay.sleep(); Option(conn.getNotifications())} match { case Some(array) if array.nonEmpty => synchronized { var received = _receiver_buffer.getOrElse(Map.empty) for (a <- array.iterator if a.getPID != self_pid) { val msg = SQL.Notification(a.getName, a.getParameter) if (!received.isDefinedAt(msg)) { val stamp = System.nanoTime() received = received + (msg -> stamp) } } _receiver_buffer = Some(received) } case _ => } } } catch { case Exn.Interrupt() => } } private def receiver_shutdown(): Unit = synchronized { if (_receiver_buffer.isDefined) { _receiver_thread.interrupt() Some(_receiver_thread) } else None }.foreach(_.join()) private def synchronized_receiver[A](body: => A): A = synchronized { if (_receiver_buffer.isEmpty) { _receiver_buffer = Some(Map.empty) _receiver_thread } body } override def listen(channel: String): Unit = synchronized_receiver { execute_statement("LISTEN " + SQL.ident(channel)) } override def unlisten(channel: String = "*"): Unit = synchronized_receiver { execute_statement("UNLISTEN " + (if (channel == "*") channel else SQL.ident(channel))) } override def send(channel: String, payload: String): Unit = synchronized_receiver { execute_statement( "NOTIFY " + SQL.ident(channel) + if_proper(payload, ", " + SQL.string(payload))) } override def receive( filter: SQL.Notification => Boolean = _ => true ): Option[List[SQL.Notification]] = synchronized { _receiver_buffer.map { received => val filtered = received.keysIterator.filter(filter).toList if (filtered.nonEmpty) { _receiver_buffer = Some(received -- filtered) filtered.map(msg => msg -> received(msg)).sortBy(_._2).map(_._1) } else Nil } } override def close(): Unit = { receiver_shutdown() super.close() if (server_close) server.close() } } }