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Documentation improvements. In particular,

Browse Source 
expand and clarify the description of the client
callback functions and how they should handle errors.

Thanks to: Antony Dovgal
This commit is contained in:
Tim Kientzle 2005-01-08 19:51:04 +00:00
parent 67afe2c071
commit 09cad9b550
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=139913
5 changed files with 148 additions and 55 deletions
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1
lib/libarchive/Makefile
View File

@ -140,6 +140,7 @@ MLINKS+= archive_read.3 archive_read_support_compression_gzip.3
MLINKS+= archive_read.3 archive_read_support_compression_none.3
MLINKS+= archive_read.3 archive_read_support_format_all.3
MLINKS+= archive_read.3 archive_read_support_format_cpio.3
MLINKS+= archive_read.3 archive_read_support_format_iso9660.3
MLINKS+= archive_read.3 archive_read_support_format_tar.3
MLINKS+= archive_util.3 archive_compression.3
MLINKS+= archive_util.3 archive_compression_name.3

78
lib/libarchive/archive_read.3
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@ -1,4 +1,4 @@
.\" Copyright (c) 2003-2004 Tim Kientzle
.\" Copyright (c) 2003-2005 Tim Kientzle
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd October 1, 2003
.Dd January 8, 2005
.Dt archive_read 3
.Os
.Sh NAME
@ -35,9 +35,10 @@
.Nm archive_read_support_compression_compress ,
.Nm archive_read_support_compression_gzip ,
.Nm archive_read_support_compression_none ,
.Nm archive_read_support_format_tar ,
.Nm archive_read_support_format_cpio ,
.Nm archive_read_support_format_all ,
.Nm archive_read_support_format_cpio ,
.Nm archive_read_support_format_iso9660 ,
.Nm archive_read_support_format_tar ,
.Nm archive_read_open ,
.Nm archive_read_open_fd ,
.Nm archive_read_open_file ,
@ -69,11 +70,13 @@
.Ft int
.Fn archive_read_support_compression_none "struct archive *"
.Ft int
.Fn archive_read_support_format_tar "struct archive *"
.Fn archive_read_support_format_all "struct archive *"
.Ft int
.Fn archive_read_support_format_cpio "struct archive *"
.Ft int
.Fn archive_read_support_format_all "struct archive *"
.Fn archive_read_support_format_iso9660 "struct archive *"
.Ft int
.Fn archive_read_support_format_tar "struct archive *"
.Ft int
.Fn archive_read_open "struct archive *" "void *client_data" "archive_open_archive_callback *" "archive_read_archive_callback *" "archive_close_archive_callback *"
.Ft int
@ -119,7 +122,7 @@ Sets the block size used for reading the archive data.
This controls the size that will be used when invoking the read
callback function.
The default is 20 records or 10240 bytes for tar formats.
.It Fn archive_read_support_compression_XXX
.It Fn archive_read_support_comression_all , Fn archive_read_support_compression_bzip2 , Fn archive_read_support_compression_compress , Fn archive_read_support_compression_gzip , Fn archive_read_support_compression_none
Enables auto-detection code and decompression support for the
specified compression.
Note that
@ -128,10 +131,10 @@ is always enabled by default.
For convenience,
.Fn archive_read_support_compression_all
enables all available decompression code.
.It Fn archive_read_support_format_XXX
.It Fn archive_read_support_format_all , Fn archive_read_support_format_cpio , Fn archive_read_support_format_iso9660 , Fn archive_read_support_format_tar
Enables support---including auto-detection code---for the
specified archive format.
In particular,
For example,
.Fn archive_read_support_format_tar
enables support for a variety of standard tar formats, old-style tar,
ustar, pax interchange format, and many common variants.
@ -251,6 +254,13 @@ or
compression and transparently performs the appropriate decompression.
It also automatically detects the archive format.
.Pp
A complete description of the
.Tn struct archive
and
.Tn struct archive_entry
objects can be found in the overview manual page for
.Xr libarchive 3 .
.Sh CLIENT CALLBACKS
The callback functions must match the following prototypes:
.Bl -item -offset indent
.It
@ -263,17 +273,46 @@ The callback functions must match the following prototypes:
.Ft typedef int
.Fn archive_close_callback "struct archive *" "void *client_data"
.El
These callback functions are called whenever the library requires
raw bytes from the archive.
Note that it is the client's responsibility to correctly
block the input.
.Pp
A complete description of the
.Tn struct archive
and
.Tn struct archive_entry
objects can be found in the overview manual page for
.Xr libarchive 3 .
The open callback is invoked by
.Fn archive_open .
It should return
.Cm ARCHIVE_OK
if the underlying file or data source is successfully
opened.
If the open fails, it should call
.Fn archive_set_error
to register an error code and message and return
.Cm ARCHIVE_FATAL .
.Pp
The read callback is invoked whenever the library
requires raw bytes from the archive.
The read callback should read data into a buffer,
set the
.Li const void **buffer
argument to point to the available data, and
return a count of the number of bytes available.
The library will invoke the read callback again
only after it has consumed this data.
The library imposes no constraints on the size
of the data blocks returned.
On end-of-file, the read callback should
return zero.
On error, the read callback should invoke
.Fn archive_set_error
to register an error code and message and
return -1.
.Pp
The close callback is invoked by archive_close when
the archive processing is complete.
The callback should return
.Cm ARCHIVE_OK
on success.
On failure, the callback should invoke
.Fn archive_set_error
to register an error code and message and
regurn
.Cm ARCHIVE_FATAL.
.Sh EXAMPLE
The following illustrates basic usage of the library.
In this example,
@ -389,6 +428,7 @@ to be returned.)
.Sh SEE ALSO
.Xr tar 1 ,
.Xr archive 3 ,
.Xr archive_util 3 ,
.Xr tar 5
.Sh HISTORY
The

28
lib/libarchive/archive_util.3
View File

@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd October 1, 2003
.Dd January 8, 2005
.Dt archive_util 3
.Os
.Sh NAME
@ -94,12 +94,34 @@ by
.Fn archive_errno
and
.Fn archive_error_string .
This function is sometimes useful within I/O callbacks.
This function should be used within I/O callbacks to set system-specific
error codes and error descriptions.
This function accepts a printf-like format string and arguments.
However, you should be careful to use only the following printf
format specifiers:
.Dq %c ,
.Dq %d ,
.Dq %jd ,
.Dq %jo ,
.Dq %ju ,
.Dq %jx ,
.Dq %ld ,
.Dq %lo ,
.Dq %lu ,
.Dq %lx ,
.Dq %o ,
.Dq %u ,
.Dq %s ,
.Dq %x ,
.Dq %% .
Field-width specifiers and other printf features are
not uniformly supported and should not be used.
.El
.Sh SEE ALSO
.Xr archive_read 3 ,
.Xr archive_write 3 ,
.Xr libarchive 3
.Xr libarchive 3 ,
.Xr printf 3
.Sh HISTORY
The
.Nm libarchive

84
lib/libarchive/archive_write.3
View File

@ -1,4 +1,4 @@
.\" Copyright (c) 2003-2004 Tim Kientzle
.\" Copyright (c) 2003-2005 Tim Kientzle
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd October 1, 2003
.Dd January 8, 2005
.Dt archive_write 3
.Os
.Sh NAME
@ -198,30 +198,6 @@ Invokes
.Fn archive_write_close
if it wasn't invoked manually, then release all resources.
.El
.Pp
The callback functions are defined as follows:
.Bl -item -offset indent
.It
.Ft typedef ssize_t
.Fn archive_write_archive_callback "struct archive *" "void *client_data" "void *buffer" "size_t length"
.It
.Ft typedef int
.Fn archive_open_archive_callback "struct archive *" "void *client_data"
.It
.Ft typedef int
.Fn archive_close_archive_callback "struct archive *" "void *client_data"
.El
For correct blocking, each call to the write callback function
should translate into a single
.Xr write 2
system call.
This is especially critical when writing tar archives to tape drives.
.Pp
More information about tar archive formats and blocking can be found
in the
.Xr tar 5
manual page.
.Pp
More information about the
.Va struct archive
object and the overall design of the library can be found in the
@ -230,6 +206,62 @@ overview.
.Sh IMPLEMENTATION
Compression support is built-in to libarchive, which uses zlib and bzlib
to handle gzip and bzip2 compression, respectively.
.Sh CLIENT CALLBACKS
To use this library, you will need to define and register
callback functions that will be invoked to write data to the
resulting archive.
These functions are registered by calling
.Fn archive_write_open :
.Bl -item -offset indent
.It
.Ft typedef int
.Fn archive_open_archive_callback "struct archive *" "void *client_data"
.El
.Pp
The open callback is invoked by
.Fn archive_write_open .
It should return
.Cm ARCHIVE_OK
if the underlying file or data source is successfully
opened.
If the open fails, it should call
.Fn archive_set_error
to register an error code and message and return
.Cm ARCHIVE_FATAL .
.Bl -item -offset indent
.It
.Ft typedef ssize_t
.Fn archive_write_archive_callback "struct archive *" "void *client_data" "void *buffer" "size_t length"
.El
.Pp
The write callback is invoked whenever the library
needs to write raw bytes to the archive.
For correct blocking, each call to the write callback function
should translate into a single
.Xr write 2
system call.
This is especially critical when writing archives to tape drives.
On success, the write callback should return the
number of bytes actually written.
On error, the callback should invoke
.Fn archive_set_error
to register an error code and message and return -1.
.Bl -item -offset indent
.It
.Ft typedef int
.Fn archive_close_archive_callback "struct archive *" "void *client_data"
.El
.Pp
The close callback is invoked by archive_close when
the archive processing is complete.
The callback should return
.Cm ARCHIVE_OK
on success.
On failure, the callback should invoke
.Fn archive_set_error
to register an error code and message and
regurn
.Cm ARCHIVE_FATAL.
.Sh EXAMPLE
The following sketch illustrates basic usage of the library.
In this example,

12
lib/libarchive/libarchive.3
View File

@ -1,4 +1,4 @@
.\" Copyright (c) 2003-2004 Tim Kientzle
.\" Copyright (c) 2003-2005 Tim Kientzle
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd October 1, 2003
.Dd January 8, 2005
.Dt LIBARCHIVE 3
.Os
.Sh NAME
@ -305,8 +305,8 @@ library was written by
Some archive formats support information that is not supported by
.Tn struct archive_entry .
Such information cannot be fully archived or restored using this library.
This includes, for example, comments, character sets, sparse
file information, or the arbitrary key/value pairs that can appear in
This includes, for example, comments, character sets,
or the arbitrary key/value pairs that can appear in
pax interchange format archives.
.Pp
Conversely, of course, not all of the information that can be
@ -315,6 +315,4 @@ stored in an
is supported by all formats.
For example, cpio formats do not support nanosecond timestamps;
old tar formats do not support large device numbers.
.Pp
The library cannot write pre-POSIX tar archives.
The support for GNU tar format is incomplete.