b1ff9c25b8
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...
190 lines
6.5 KiB
C
190 lines
6.5 KiB
C
/*-
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* Copyright (c) 2003-2007 Tim Kientzle
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef ARCHIVE_READ_PRIVATE_H_INCLUDED
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#define ARCHIVE_READ_PRIVATE_H_INCLUDED
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#include "archive.h"
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#include "archive_string.h"
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#include "archive_private.h"
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struct archive_read;
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struct archive_reader;
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struct archive_read_source;
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/*
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* A "reader" knows how to provide blocks. That can include something
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* that reads blocks from disk or socket or a transformation layer
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* that reads blocks from another source and transforms them. This
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* includes decompression and decryption filters.
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*
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* How bidding works:
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* * The bid manager reads the first block from the current source.
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* * It shows that block to each registered bidder.
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* * The winning bidder is initialized (with the block and information
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* about the source)
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* * The winning bidder becomes the new source and the process repeats
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* This ends only when no reader provides a non-zero bid.
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*/
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struct archive_reader {
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/* Configuration data for the reader. */
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void *data;
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/* Bidder is handed the initial block from its source. */
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int (*bid)(struct archive_reader *, const void *buff, size_t);
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/* Init() is given the archive, upstream source, and the initial
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* block above. It returns a populated source structure. */
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struct archive_read_source *(*init)(struct archive_read *,
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struct archive_reader *, struct archive_read_source *source,
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const void *, size_t);
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/* Release the reader and any configuration data it allocated. */
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int (*free)(struct archive_reader *);
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};
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/*
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* A "source" is an instance of a reader. This structure is
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* allocated and initialized by the init() method of a reader
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* above.
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*/
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struct archive_read_source {
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/* Essentially all sources will need these values, so
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* just declare them here. */
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struct archive_reader *reader; /* Reader that I'm an instance of. */
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struct archive_read_source *upstream; /* Who I get blocks from. */
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struct archive_read *archive; /* associated archive. */
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/* Return next block. */
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ssize_t (*read)(struct archive_read_source *, const void **);
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/* Skip forward this many bytes. */
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int64_t (*skip)(struct archive_read_source *self, int64_t request);
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/* Close (recursively) and free(self). */
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int (*close)(struct archive_read_source *self);
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/* My private data. */
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void *data;
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};
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/*
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* The client source is almost the same as an internal source.
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*
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* TODO: Make archive_read_source and archive_read_client identical so
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* that users of the library can easily register their own
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* transformation filters. This will probably break the API/ABI and
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* so should be deferred until libarchive 3.0.
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*/
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struct archive_read_client {
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archive_open_callback *opener;
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archive_read_callback *reader;
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archive_skip_callback *skipper;
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archive_close_callback *closer;
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void *data;
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};
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struct archive_read {
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struct archive archive;
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struct archive_entry *entry;
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/* Dev/ino of the archive being read/written. */
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dev_t skip_file_dev;
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ino_t skip_file_ino;
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/*
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* Used by archive_read_data() to track blocks and copy
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* data to client buffers, filling gaps with zero bytes.
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*/
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const char *read_data_block;
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off_t read_data_offset;
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off_t read_data_output_offset;
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size_t read_data_remaining;
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/* Callbacks to open/read/write/close client archive stream. */
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struct archive_read_client client;
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/* Registered readers. */
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struct archive_reader readers[8];
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/* Source */
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struct archive_read_source *source;
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/* File offset of beginning of most recently-read header. */
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off_t header_position;
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/* Used by reblocking logic. */
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char *buffer;
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size_t buffer_size;
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char *next; /* Current read location. */
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size_t avail; /* Bytes in my buffer. */
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const void *client_buff; /* Client buffer information. */
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size_t client_total;
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const char *client_next;
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size_t client_avail;
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char end_of_file;
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char fatal;
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/*
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* Format detection is mostly the same as compression
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* detection, with one significant difference: The bidders
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* use the read_ahead calls above to examine the stream rather
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* than having the supervisor hand them a block of data to
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* examine.
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*/
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struct archive_format_descriptor {
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void *data;
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int (*bid)(struct archive_read *);
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int (*read_header)(struct archive_read *, struct archive_entry *);
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int (*read_data)(struct archive_read *, const void **, size_t *, off_t *);
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int (*read_data_skip)(struct archive_read *);
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int (*cleanup)(struct archive_read *);
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} formats[8];
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struct archive_format_descriptor *format; /* Active format. */
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/*
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* Various information needed by archive_extract.
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*/
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struct extract *extract;
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int (*cleanup_archive_extract)(struct archive_read *);
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};
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int __archive_read_register_format(struct archive_read *a,
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void *format_data,
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int (*bid)(struct archive_read *),
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int (*read_header)(struct archive_read *, struct archive_entry *),
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int (*read_data)(struct archive_read *, const void **, size_t *, off_t *),
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int (*read_data_skip)(struct archive_read *),
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int (*cleanup)(struct archive_read *));
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struct archive_reader
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*__archive_read_get_reader(struct archive_read *a);
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const void
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*__archive_read_ahead(struct archive_read *, size_t, ssize_t *);
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ssize_t
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__archive_read_consume(struct archive_read *, size_t);
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int64_t
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__archive_read_skip(struct archive_read *, int64_t);
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#endif
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