core/Lucy/Store/CompoundFileReader.cfh

/* 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;

/** Read from a compound file.
 *
 * A CompoundFileReader provides access to the files contained within the
 * compound file format written by CompoundFileWriter.  The InStream objects
 * it spits out behave largely like InStreams opened against discrete files --
 * e.g. Seek(0) seeks to the beginning of the sub-file, not the beginning of
 * the compound file.
 *
 * Each of the InStreams spawned maintains its own memory buffer; however,
 * they all share a single filehandle.  This allows Lucy to get around
 * the limitations that many operating systems place on the number of
 * available filehandles.
 */

class Lucy::Store::CompoundFileReader cnick CFReader
    inherits Lucy::Store::Folder {

    Folder       *real_folder;
    Hash         *records;
    InStream     *instream;
    int32_t       format;

    inert incremented nullable CompoundFileReader*
    open(Folder *folder);

    /** Return a new CompoundFileReader or set Err_error and return NULL.
     *
     * @param folder A folder containing compound files.
     */
    inert nullable CompoundFileReader*
    do_open(CompoundFileReader *self, Folder *folder);

    Folder*
    Get_Real_Folder(CompoundFileReader *self);

    void
    Set_Path(CompoundFileReader *self, const CharBuf *path);

    public void
    Close(CompoundFileReader *self);

    public void
    Destroy(CompoundFileReader *self);

    bool_t
    Local_Delete(CompoundFileReader *self, const CharBuf *name);

    bool_t
    Local_Exists(CompoundFileReader *self, const CharBuf *name);

    bool_t
    Local_Is_Directory(CompoundFileReader *self, const CharBuf *name);

    incremented nullable FileHandle*
    Local_Open_FileHandle(CompoundFileReader *self, const CharBuf *name,
                          uint32_t flags);

    incremented nullable InStream*
    Local_Open_In(CompoundFileReader *self, const CharBuf *name);

    bool_t
    Local_MkDir(CompoundFileReader *self, const CharBuf *name);

    nullable Folder*
    Local_Find_Folder(CompoundFileReader *self, const CharBuf *name);

    incremented nullable DirHandle*
    Local_Open_Dir(CompoundFileReader *self);
}

/** DirHandle for CompoundFileReader.
 */
class Lucy::Store::CFReaderDirHandle cnick CFReaderDH
    inherits Lucy::Store::DirHandle {

    CompoundFileReader *cf_reader;
    VArray             *elems;
    int32_t             tick;

    inert incremented CFReaderDirHandle*
    new(CompoundFileReader *cf_reader);

    inert CFReaderDirHandle*
    init(CFReaderDirHandle *self, CompoundFileReader *cf_reader);

    bool_t
    Next(CFReaderDirHandle *self);

    bool_t
    Entry_Is_Dir(CFReaderDirHandle *self);

    bool_t
    Close(CFReaderDirHandle *self);
}