167 lines
5.7 KiB
Groff
167 lines
5.7 KiB
Groff
.\" zip_source_layered.mdoc -- create layered source from function
|
|
.\" Copyright (C) 2004-2022 Dieter Baron and Thomas Klausner
|
|
.\"
|
|
.\" This file is part of libzip, a library to manipulate ZIP archives.
|
|
.\" The authors can be contacted at <info@libzip.org>
|
|
.\"
|
|
.\" 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.
|
|
.\" 3. The names of the authors may not be used to endorse or promote
|
|
.\" products derived from this software without specific prior
|
|
.\" written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``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 AUTHORS 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.
|
|
.\"
|
|
.Dd January 20, 2023
|
|
.Dt ZIP_SOURCE_LAYERED 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm zip_source_layered ,
|
|
.Nm zip_source_layered_create
|
|
.Nd create layered data source from function
|
|
.Sh LIBRARY
|
|
libzip (-lzip)
|
|
.Sh SYNOPSIS
|
|
.In zip.h
|
|
.Ft zip_source_t *
|
|
.Fn zip_source_layered "zip_t *archive" "zip_source_t *source" "zip_source_layered_callback fn" "void *userdata"
|
|
.Ft zip_source_t *
|
|
.Fn zip_source_layered_create "zip_source_t *source" "zip_source_layered_callback fn" "void *userdata" "zip_error_t *error"
|
|
.Sh DESCRIPTION
|
|
The functions
|
|
.Fn zip_source_layered
|
|
and
|
|
.Fn zip_source_layered_create
|
|
create a layered zip source from the user-provided function
|
|
.Ar fn ,
|
|
which must be of the following type:
|
|
.Pp
|
|
.Ft typedef zip_int64_t
|
|
.Fo \fR(*\zip_source_layered_callback\fR)\fP
|
|
.Fa "zip_source_t *source" "void *userdata" "void *data" "zip_uint64_t length" "zip_source_cmd_t cmd"
|
|
.Fc
|
|
.Pp
|
|
.Ar archive
|
|
or
|
|
.Ar error
|
|
are used for reporting errors and can be
|
|
.Dv NULL .
|
|
.Pp
|
|
When called by the library, the first argument is the
|
|
.Ar source
|
|
of the lower layer, the second argument is the
|
|
.Ar userdata
|
|
argument supplied to the function.
|
|
The next two arguments are a buffer
|
|
.Ar data
|
|
of size
|
|
.Ar length
|
|
when data is passed in or expected to be returned, or else
|
|
.Dv NULL
|
|
and 0.
|
|
The last argument,
|
|
.Ar cmd ,
|
|
specifies which action the function should perform.
|
|
.Pp
|
|
See
|
|
.Xr zip_source_function 3
|
|
for a description of the commands.
|
|
.Pp
|
|
A layered source transforms the data or metadata of the source below in some way.
|
|
Layered sources can't support writing and are not sufficient to cleanly add support for additional compression or encryption methods.
|
|
This may be revised in a later release of libzip.
|
|
.Pp
|
|
On success, the layered source takes ownership of
|
|
.Ar source .
|
|
The caller should not free it.
|
|
.Pp
|
|
The interaction with the lower layer depends on the command:
|
|
.Ss Dv ZIP_SOURCE_ACCEPT_EMPTY
|
|
If the layered source supports this command, the lower layer is not called automatically.
|
|
Otherwise, the return value of the lower source is used.
|
|
.Ss Dv ZIP_SOURCE_CLOSE
|
|
The lower layer is closed after the callback returns.
|
|
.Ss Dv ZIP_SOURCE_ERROR
|
|
The lower layer is not called automatically.
|
|
If you need to retrieve error information from the lower layer, use
|
|
.Xr zip_error_set_from_source 3
|
|
or
|
|
.Xr zip_source_pass_to_lower_layer 3 .
|
|
.Ss Dv ZIP_SOURCE_FREE
|
|
The lower layer is freed after the callback returns.
|
|
.Ss Dv ZIP_SOURCE_GET_FILE_ATTRIBUTES
|
|
The attributes of the lower layer are merged with the attributes returned by the callback: information set by the callback wins over the lower layer, with the following exceptions: the higher
|
|
.Ar version_needed
|
|
is used, and
|
|
.Ar general_purpose_bit_flags
|
|
are only overwritten if the corresponding bit is set in
|
|
.Ar general_purpose_bit_mask .
|
|
.Ss Dv ZIP_SOURCE_OPEN
|
|
The lower layer is opened before the callback is called.
|
|
.Ss Dv ZIP_SOURCE_READ
|
|
The lower layer is not called automatically.
|
|
.Ss Dv ZIP_SOURCE_SEEK
|
|
The lower layer is not called automatically.
|
|
.Ss Dv ZIP_SOURCE_STAT
|
|
.Ar data
|
|
contains the stat information from the lower layer when the callback is called.
|
|
.Ss Dv ZIP_SOURCE_SUPPORTS
|
|
.Ar data
|
|
contains the bitmap of commands supported by the lower layer when the callback is called.
|
|
Since layered sources can't support writing, all commands related to writing are stripped from the returned support bitmap.
|
|
.Ss Dv ZIP_SOURCE_TELL
|
|
The lower layer is not called automatically.
|
|
.Sh RETURN VALUES
|
|
Upon successful completion, the created source is returned.
|
|
Otherwise,
|
|
.Dv NULL
|
|
is returned and the error code in
|
|
.Ar archive
|
|
or
|
|
.Ar error
|
|
is set to indicate the error (unless
|
|
it is
|
|
.Dv NULL ) .
|
|
.Sh ERRORS
|
|
.Fn zip_source_layered
|
|
fails if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er ZIP_ER_MEMORY
|
|
Required memory could not be allocated.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr libzip 3 ,
|
|
.Xr zip_file_add 3 ,
|
|
.Xr zip_file_attributes_init 3 ,
|
|
.Xr zip_file_replace 3 ,
|
|
.Xr zip_source 3 ,
|
|
.Xr zip_source_function 3 ,
|
|
.Xr zip_source_pass_to_lower_layer 3
|
|
.Sh HISTORY
|
|
.Fn zip_source_layered
|
|
and
|
|
.Fn zip_source_layered_create
|
|
were added in libzip 1.10.
|
|
.Sh AUTHORS
|
|
.An -nosplit
|
|
.An Dieter Baron Aq Mt dillo@nih.at
|
|
and
|
|
.An Thomas Klausner Aq Mt wiz@gatalith.at
|