Add support for downloading single blobs

[ps-cgit] / README

diff --git a/README b/README
index 5917c37ce30b3f0a374c9fa376955f51f1d7bfbf..a14418e8db8af0e239b524a0f37505e94f9993ba 100644 (file)
--- a/README
+++ b/README
@@ -1,54 +1,55 @@
-Cache algorithm
-===============
-
-Cgit normally returns cached pages when invoked. If there is no cache file, or
-the cache file has expired, it is regenerated. Finally, the cache file is 
-printed on stdout.
-
-When it is decided that a cache file needs to be regenerated, an attempt is 
-made to create a corresponding lockfile. If this fails, the process gives up
-and uses the expired cache file instead.
-
-When there is no cache file for a request, an attempt is made to create a 
-corresponding lockfile. If this fails, the process calls sched_yield(2) before
-restarting the request handling.
-
-In pseudocode:
-
-       name = generate_cache_name(request);
-top:
-       if (!exists(name)) {
-               if (lock_cache(name)) {
-                       generate_cache(request, name);
-                       unlock_cache(name);
-               } else {
-                       sched_yield();
-                       goto top;
-               }
-       } else if (expired(name)) {
-               if (lock_cache(name)) {
-                       generate_cache(request, name);
-                       unlock_cache(name);
-               }
-       }
-       print_file(name);
-
-
-The following options can be set in /etc/cgitrc to control cache behaviour:
-  cache-root:        root directory for cache files
-  cache-root-ttl:    TTL for the repo listing page
-  cache-repo-ttl:    TTL for any repos summary page
-  cache-dynamic-ttl: TTL for pages with symbolic references (not SHA1)
-  cache-static-ttl:  TTL for pages with sha1 references
-
-TTL is specified in minutes, -1 meaning "infinite caching". 
-
-
-Naming of cache files
----------------------
-Repository listing:  <cachedir>/index.html
-Repository summary:  <cachedir>/<repo>/index.html
-Repository subpage:  <cachedir>/<repo>/<page>/<querystring>.html
-
-The corresponding lock files have a ".lock" suffix.
 
+                       cgit - cgi for git
+
+
+This is an attempt to create a fast web interface for the git scm, using a
+builtin cache to decrease server io-pressure.
+
+
+Installation
+
+  $ make gitsrc=<path>
+  $ su
+  $ make prefix=<path> install
+
+
+Default value for gitsrc is "../git", and this directory should contain the
+git sources.
+
+Default value for prefix is "/var/www/htdocs/cgit". This directory will 
+contain "cgit.cgi" and "cgit.css" after 'make install'.
+
+After installation, httpd.conf probably must be updated with a Directory-
+section for cgit, possibly something like this:
+
+  <Directory "/var/www/htdocs/cgit/">
+      AllowOverride None
+      Options ExecCGI
+      Order allow,deny
+      Allow from all
+  </Directory>
+
+
+Runtime configuration
+
+The file /etc/cgitrc is read by cgit before handling a request. In addition
+to runtime parameters, this file also contains a list of the repositories 
+displayed by cgit.
+
+A template cgitrc is shipped with the sources, and all parameters and default
+values are documented in this file. 
+
+
+The cache
+
+When cgit is invoked it looks for a cachefile matching the request and 
+returns it to the client. If no such cachefile exist (or if it has expired), 
+the content for the request is written into the proper cachefile before the
+file is returned.
+
+If the cachefile has expired but cgit is unable to obtain a lock for it, the 
+stale cachefile is returned to the client. This is done to favour page
+throughput over page freshness.
+
+The generated content contains the complete response to the client, including
+the http-headers "Modified" and "Expires".