freebsd-dev/lib/libarchive/archive_read_private.h
Tim Kientzle b1ff9c25b8 MfP4: Big read filter refactoring.
This is an attempt to eliminate a lot of redundant
code from the read ("decompression") filters by
changing them to juggle arbitrary-sized blocks
and consolidate reblocking code at a single point
in archive_read.c.

Along the way, I've changed the internal read/consume
API used by the format handlers to a slightly
different style originally suggested by des@.  It
does seem to simplify a lot of common cases.

The most dramatic change is, of course, to
archive_read_support_compression_none(), which
has just evaporated into a no-op as the blocking
code this used to hold has all been moved up
a level.

There's at least one more big round of refactoring
yet to come before the individual filters are as
straightforward as I think they should be...
2008-12-06 06:45:15 +00:00

190 lines
6.5 KiB
C

/*-
* Copyright (c) 2003-2007 Tim Kientzle
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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(S) 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.
*
* $FreeBSD$
*/
#ifndef ARCHIVE_READ_PRIVATE_H_INCLUDED
#define ARCHIVE_READ_PRIVATE_H_INCLUDED
#include "archive.h"
#include "archive_string.h"
#include "archive_private.h"
struct archive_read;
struct archive_reader;
struct archive_read_source;
/*
* A "reader" knows how to provide blocks. That can include something
* that reads blocks from disk or socket or a transformation layer
* that reads blocks from another source and transforms them. This
* includes decompression and decryption filters.
*
* How bidding works:
* * The bid manager reads the first block from the current source.
* * It shows that block to each registered bidder.
* * The winning bidder is initialized (with the block and information
* about the source)
* * The winning bidder becomes the new source and the process repeats
* This ends only when no reader provides a non-zero bid.
*/
struct archive_reader {
/* Configuration data for the reader. */
void *data;
/* Bidder is handed the initial block from its source. */
int (*bid)(struct archive_reader *, const void *buff, size_t);
/* Init() is given the archive, upstream source, and the initial
* block above. It returns a populated source structure. */
struct archive_read_source *(*init)(struct archive_read *,
struct archive_reader *, struct archive_read_source *source,
const void *, size_t);
/* Release the reader and any configuration data it allocated. */
int (*free)(struct archive_reader *);
};
/*
* A "source" is an instance of a reader. This structure is
* allocated and initialized by the init() method of a reader
* above.
*/
struct archive_read_source {
/* Essentially all sources will need these values, so
* just declare them here. */
struct archive_reader *reader; /* Reader that I'm an instance of. */
struct archive_read_source *upstream; /* Who I get blocks from. */
struct archive_read *archive; /* associated archive. */
/* Return next block. */
ssize_t (*read)(struct archive_read_source *, const void **);
/* Skip forward this many bytes. */
int64_t (*skip)(struct archive_read_source *self, int64_t request);
/* Close (recursively) and free(self). */
int (*close)(struct archive_read_source *self);
/* My private data. */
void *data;
};
/*
* The client source is almost the same as an internal source.
*
* TODO: Make archive_read_source and archive_read_client identical so
* that users of the library can easily register their own
* transformation filters. This will probably break the API/ABI and
* so should be deferred until libarchive 3.0.
*/
struct archive_read_client {
archive_open_callback *opener;
archive_read_callback *reader;
archive_skip_callback *skipper;
archive_close_callback *closer;
void *data;
};
struct archive_read {
struct archive archive;
struct archive_entry *entry;
/* Dev/ino of the archive being read/written. */
dev_t skip_file_dev;
ino_t skip_file_ino;
/*
* Used by archive_read_data() to track blocks and copy
* data to client buffers, filling gaps with zero bytes.
*/
const char *read_data_block;
off_t read_data_offset;
off_t read_data_output_offset;
size_t read_data_remaining;
/* Callbacks to open/read/write/close client archive stream. */
struct archive_read_client client;
/* Registered readers. */
struct archive_reader readers[8];
/* Source */
struct archive_read_source *source;
/* File offset of beginning of most recently-read header. */
off_t header_position;
/* Used by reblocking logic. */
char *buffer;
size_t buffer_size;
char *next; /* Current read location. */
size_t avail; /* Bytes in my buffer. */
const void *client_buff; /* Client buffer information. */
size_t client_total;
const char *client_next;
size_t client_avail;
char end_of_file;
char fatal;
/*
* Format detection is mostly the same as compression
* detection, with one significant difference: The bidders
* use the read_ahead calls above to examine the stream rather
* than having the supervisor hand them a block of data to
* examine.
*/
struct archive_format_descriptor {
void *data;
int (*bid)(struct archive_read *);
int (*read_header)(struct archive_read *, struct archive_entry *);
int (*read_data)(struct archive_read *, const void **, size_t *, off_t *);
int (*read_data_skip)(struct archive_read *);
int (*cleanup)(struct archive_read *);
} formats[8];
struct archive_format_descriptor *format; /* Active format. */
/*
* Various information needed by archive_extract.
*/
struct extract *extract;
int (*cleanup_archive_extract)(struct archive_read *);
};
int __archive_read_register_format(struct archive_read *a,
void *format_data,
int (*bid)(struct archive_read *),
int (*read_header)(struct archive_read *, struct archive_entry *),
int (*read_data)(struct archive_read *, const void **, size_t *, off_t *),
int (*read_data_skip)(struct archive_read *),
int (*cleanup)(struct archive_read *));
struct archive_reader
*__archive_read_get_reader(struct archive_read *a);
const void
*__archive_read_ahead(struct archive_read *, size_t, ssize_t *);
ssize_t
__archive_read_consume(struct archive_read *, size_t);
int64_t
__archive_read_skip(struct archive_read *, int64_t);
#endif