Copyright 2000-2001 Olaf Wagner.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgment:
* This product includes software developed by Olaf Wagner.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
MODULE ClassDB;
IMPORT
ClientClass, ErrMsg, FileAttr, Logger, OSError, OSErrorPosix,
Pathname, Rd, Text, Thread, Time, Uerror;
PROCEDURE Init(fn: Pathname.T; logger: Logger.T := NIL)
RAISES {Rd.Failure, Thread.Alerted} =
BEGIN
LOCK mu DO
RealInit(fn, logger);
END;
END Init;
PROCEDURE RealInit(fn: Pathname.T; logger: Logger.T := NIL)
RAISES {Rd.Failure, Thread.Alerted} =
BEGIN
IF db = NIL THEN
db := NEW(ClientClass.DB);
dbPath := fn;
dbLogger := logger;
dbModTime := GetModTime(fn, logger);
dbRefreshTime := Time.Now();
END;
EVAL db.init(fn);
END RealInit;
PROCEDURE GetClass(name: TEXT) : ClientClass.T =
BEGIN
LOCK mu DO
RETURN db.getClass(name);
END;
END GetClass;
PROCEDURE Get(path: Pathname.T;
maxAge: Time.T;
logger: Logger.T := NIL): ClientClass.DB
RAISES {Rd.Failure, Thread.Alerted} =
VAR
now := Time.Now();
fileTime := GetModTime(path, logger);
BEGIN
LOCK mu DO
IF fileTime < 0.0d0 THEN
RETURN ClientClass.FreeAccessDB();
END;
IF Text.Equal(path, dbPath) AND
dbModTime = fileTime AND
dbRefreshTime >= now - maxAge THEN
RETURN db;
END;
db := NIL;
RealInit(path, logger);
RETURN db;
END;
END Get;
PROCEDURE GetModTime(fn: Pathname.T; logger: Logger.T) : Time.T =
Returns the modification time of fn, or -1.0d0 if that information
cannot be gotten. In the latter case, a warning is logged unless the
file simply doesn't exist.
VAR
attr: FileAttr.T;
fileTime: Time.T;
BEGIN
TRY
attr := FileAttr.FromPathname(fn, follow := TRUE);
fileTime := FileAttr.GetModTime(attr);
EXCEPT OSError.E(list) =>
IF list.head # EnoentAtom THEN
Log(logger, Logger.Priority.Warning,
"Cannot get attributes for \"" & fn & "\": " &
ErrMsg.StrError(list));
END;
fileTime := -1.0d0;
END;
RETURN fileTime;
END GetModTime;
PROCEDURE Log(logger: Logger.T;
priority: Logger.Priority;
msg: TEXT) =
BEGIN
IF logger # NIL THEN
Logger.Put(logger, priority, msg);
END;
END Log;
VAR (* CONST *)
EnoentAtom := OSErrorPosix.ErrnoAtom(Uerror.ENOENT);
VAR
mu:= NEW(MUTEX);
db: ClientClass.DB;
dbPath: Pathname.T;
dbLogger: Logger.T;
dbModTime: Time.T;
dbRefreshTime: Time.T;
BEGIN
db := NIL;
dbPath := "";
dbLogger := NIL;
dbModTime := -1.0d0;
dbRefreshTime := -1.0d0;
END ClassDB.