/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

parcel Lucy;

/** Create Locks.
 *
 * LockFactory is used to spin off interprocess mutex locks used by various
 * index reading and writing components.  The default implementation uses
 * lockfiles, but LockFactory subclasses which are implemented using
 * alternatives such as flock() are possible.
 */

class Lucy::Store::LockFactory cnick LockFact
    inherits Lucy::Object::Obj {

    Folder  *folder;
    CharBuf *host;

    inert incremented LockFactory*
    new(Folder *folder, const CharBuf *host);

    /**
     * @param folder A L<Lucy::Store::Folder>.
     * @param host An identifier which should be unique per-machine.
     */
    public inert LockFactory*
    init(LockFactory *self, Folder *folder, const CharBuf *host);

    /** Return a Lock object, which, once Obtain() returns successfully,
     * maintains an exclusive lock on a resource.
     *
     * @param name A file-system-friendly id which identifies the
     * resource to be locked.
     * @param timeout Time in milliseconds to keep retrying before abandoning
     * the attempt to Obtain() a lock.
     * @param interval Time in milliseconds between retries.
     */
    public incremented Lock*
    Make_Lock(LockFactory *self, const CharBuf *name, int32_t timeout = 0,
              int32_t interval = 100);

    /** Return a Lock object for which Shared() returns true, and which
     * maintains a non-exclusive lock on a resource once Obtain() returns
     * success.
     *
     * @param name A file-system-friendly id which identifies the
     * resource to be locked.
     * @param timeout Time in milliseconds to keep retrying before abandoning
     * the attempt to Obtain() a lock.
     * @param interval Time in milliseconds between retries.
     */
    public incremented Lock*
    Make_Shared_Lock(LockFactory *self, const CharBuf *name,
                     int32_t timeout = 0, int32_t interval = 100);

    public void
    Destroy(LockFactory *self);
}