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authorGravatar Lars Hjemli <hjemli@gmail.com>2006-12-11 06:31:36 (JST)
committerGravatar Lars Hjemli <hjemli@gmail.com>2006-12-11 06:31:36 (JST)
commit25105d7ecaba474d4b7c364ebb586aac3dfc5abb (patch)
tree8beb08db1399b8efb8c7fbcd936044ae7fc232e6 /cache.c
parent856c026e221d8ed82c5b75bc8da4bd65e89ea953 (diff)
downloadcgit-25105d7ecaba474d4b7c364ebb586aac3dfc5abb.zip
cgit-25105d7ecaba474d4b7c364ebb586aac3dfc5abb.tar.gz
Add caching infrastructure
This enables internal caching of page output. Page requests are split into four groups: 1) repo listing (front page) 2) repo summary 3) repo pages w/symbolic references in query string 4) repo pages w/constant sha1's in query string Each group has a TTL specified in minutes. When a page is requested, a cached filename is stat(2)'ed and st_mtime is compared to time(2). If TTL has expired (or the file didn't exist), the cached file is regenerated. When generating a cached file, locking is used to avoid parallell processing of the request. If multiple processes tries to aquire the same lock, the ones who fail to get the lock serves the (expired) cached file. If the cached file don't exist, the process instead calls sched_yield(2) before restarting the request processing. Signed-off-by: Lars Hjemli <hjemli@gmail.com>
Diffstat (limited to 'cache.c')
-rw-r--r--cache.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/cache.c b/cache.c
new file mode 100644
index 0000000..1be1ea4
--- /dev/null
+++ b/cache.c
@@ -0,0 +1,86 @@
1#include "cgit.h"
2
3const int NOLOCK = -1;
4
5int cache_lookup(struct cacheitem *item)
6{
7 if (!cgit_query_repo) {
8 item->name = xstrdup(fmt("%s/index.html", cgit_cache_root));
9 item->ttl = cgit_cache_root_ttl;
10 } else if (!cgit_query_page) {
11 item->name = xstrdup(fmt("%s/%s/index.html", cgit_cache_root,
12 cgit_query_repo));
13 item->ttl = cgit_cache_repo_ttl;
14 } else {
15 item->name = xstrdup(fmt("%s/%s/%s/%s.html", cgit_cache_root,
16 cgit_query_repo, cgit_query_page,
17 cgit_querystring));
18 if (cgit_query_has_symref)
19 item->ttl = cgit_cache_dynamic_ttl;
20 else if (cgit_query_has_sha1)
21 item->ttl = cgit_cache_static_ttl;
22 else
23 item->ttl = cgit_cache_repo_ttl;
24 }
25 if (stat(item->name, &item->st)) {
26 item->st.st_mtime = 0;
27 return 0;
28 }
29 return 1;
30}
31
32int cache_create_dirs()
33{
34 char *path;
35
36 if (!cgit_query_repo)
37 return 0;
38
39 path = fmt("%s/%s", cgit_cache_root, cgit_query_repo);
40 if (mkdir(path, S_IRWXU) && errno!=EEXIST)
41 return 0;
42
43 if (cgit_query_page) {
44 path = fmt("%s/%s/%s", cgit_cache_root, cgit_query_repo,
45 cgit_query_page);
46 if (mkdir(path, S_IRWXU) && errno!=EEXIST)
47 return 0;
48 }
49 return 1;
50}
51
52int cache_lock(struct cacheitem *item)
53{
54 int ret;
55 char *lockfile = fmt("%s.lock", item->name);
56
57 top:
58 item->fd = open(lockfile, O_WRONLY | O_CREAT | O_EXCL, S_IRUSR|S_IWUSR);
59 if (item->fd == NOLOCK && errno == ENOENT && cache_create_dirs())
60 goto top;
61 if (item->fd == NOLOCK && errno == EEXIST) {
62 struct stat st;
63 time_t t;
64 if (stat(lockfile, &st))
65 return ret;
66 t = time(NULL);
67 if (t-st.st_mtime > cgit_cache_max_create_time &&
68 !unlink(lockfile))
69 goto top;
70 return 0;
71 }
72 return (item->fd > 0);
73}
74
75int cache_unlock(struct cacheitem *item)
76{
77 close(item->fd);
78 return (rename(fmt("%s.lock", item->name), item->name) == 0);
79}
80
81int cache_expired(struct cacheitem *item)
82{
83 if (item->ttl < 0)
84 return 0;
85 return item->st.st_mtime + item->ttl * 60 < time(NULL);
86}