New ah_GET_GETCONF macro, better abstraction in the rest.

[apt.git] / doc / method.sgml

diff --git a/doc/method.sgml b/doc/method.sgml
index d1ebddcf571044c217da73778f9573998ba1c3ef..95fb8a52bdfefc0435c54656e313d5e7fd89b339 100644 (file)
--- a/doc/method.sgml
+++ b/doc/method.sgml
@@ -4,7 +4,7 @@
 <title>APT Method Interface </title>
 
 <author>Jason Gunthorpe <email>jgg@debian.org</email></author>
-<version>$Id: method.sgml,v 1.5 1998/12/04 21:16:54 jgg Exp $</version>
+<version>$Id: method.sgml,v 1.7 1999/10/18 00:37:36 jgg Exp $</version>
 
 <abstract>
 This document describes the interface that APT uses to the archive
@@ -33,7 +33,7 @@ For more details, on Debian GNU/Linux systems, see the file
 
 <p>
 The APT method interface allows APT to acquire archive files (.deb), index
-files (Packages, Revision, Mirrors) and source files (.tar.gz, .diff). It
+files (Packages, Release, Mirrors) and source files (.tar.gz, .diff). It
 is a general, extensible system designed to satisfy all of these
 requirements:
 
@@ -219,6 +219,9 @@ the ones it wants.
 <tag>Pipeline<item>The method is capable of pipelining.
 <tag>Local<item>The method only returns Filename: feilds.
 <tag>Send-Config<item>Send configuration to the method.
+<tag>Needs-Cleanup<item>The process is kept around while the files it returned
+are being used. This is primarily intended for CDROM and File URIs that need
+to unmount filesystems.
 <tag>Version<item>Version string for the method
 </taglist>
 
@@ -229,7 +232,8 @@ This is a list of which headers each status code can use
 Displays the capabilities of the method. Methods should set the
 pipeline bit if their underlying protocol supports pipeling. The
 only known method that does support pipelining is http.
-Fields: Version, Single-Instance, Pre-Scan, Pipeline, Send-Config
+Fields: Version, Single-Instance, Pre-Scan, Pipeline, Send-Config, 
+Needs-Cleanup
 
 <tag>101 Log<item>
 A log message may be printed to the screen if debugging is enabled. This
@@ -307,9 +311,42 @@ Fields: Media, Fail
 
 </sect>
                                                                   <!-- }}} -->
-<!-- Examples                                                         {{{ -->
+<!-- Method Notes                                                     {{{ -->
 <!-- ===================================================================== -->
-<sect>Examples
+<sect>Notes
+
+<p>
+The methods supplied by the stock apt are:
+<enumlist>
+<item>cdrom - For Multi-Disc CDROMs
+<item>copy - (internal) For copying files around the filesystem
+<item>file - For local files
+<item>gzip - (internal) For decompression
+<item>http - For HTTP servers
+</enumlist>
+
+<p>
+The two internal methods, copy and gzip, are used by the acquire code to
+parallize and simplify the automatic decompression of package files as well 
+as copying package files around the file system. Both methods can be seen to 
+act the same except that one decompresses on the fly. APT uses them by
+generating a copy URI that is formed identically to a file URI. The destination
+file is send as normal. The method then takes the file specified by the 
+URI and writes it to the destination file. A typical set of operations may
+be:
+<example>
+http://foo.com/Packages.gz -> /bar/Packages.gz
+gzip:/bar/Packages.gz -> /bar/Packages.decomp
+rename Packages.decomp to /final/Packages
+</example>
+
+<p>
+The http method implements a fully featured HTTP/1.1 client that supports
+deep pipelining and reget. It works best when coupled with an apache 1.3
+server. The file method simply generates failures or success responses with
+the filename field set to the proper location. The cdrom method acts the same
+except that it checks that the mount point has a valid cdrom in it. It does 
+this by (effectively) computing a md5 hash of 'ls -l' on the mountpoint.
 
 </sect>
                                                                   <!-- }}} -->