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-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 @@
+#include "cgit.h"
+
+const int NOLOCK = -1;
+
+int cache_lookup(struct cacheitem *item)
+{
+ if (!cgit_query_repo) {
+ item->name = xstrdup(fmt("%s/index.html", cgit_cache_root));
+ item->ttl = cgit_cache_root_ttl;
+ } else if (!cgit_query_page) {
+ item->name = xstrdup(fmt("%s/%s/index.html", cgit_cache_root,
+ cgit_query_repo));
+ item->ttl = cgit_cache_repo_ttl;
+ } else {
+ item->name = xstrdup(fmt("%s/%s/%s/%s.html", cgit_cache_root,
+ cgit_query_repo, cgit_query_page,
+ cgit_querystring));
+ if (cgit_query_has_symref)
+ item->ttl = cgit_cache_dynamic_ttl;
+ else if (cgit_query_has_sha1)
+ item->ttl = cgit_cache_static_ttl;
+ else
+ item->ttl = cgit_cache_repo_ttl;
+ }
+ if (stat(item->name, &item->st)) {
+ item->st.st_mtime = 0;
+ return 0;
+ }
+ return 1;
+}
+
+int cache_create_dirs()
+{
+ char *path;
+
+ if (!cgit_query_repo)
+ return 0;
+
+ path = fmt("%s/%s", cgit_cache_root, cgit_query_repo);
+ if (mkdir(path, S_IRWXU) && errno!=EEXIST)
+ return 0;
+
+ if (cgit_query_page) {
+ path = fmt("%s/%s/%s", cgit_cache_root, cgit_query_repo,
+ cgit_query_page);
+ if (mkdir(path, S_IRWXU) && errno!=EEXIST)
+ return 0;
+ }
+ return 1;
+}
+
+int cache_lock(struct cacheitem *item)
+{
+ int ret;
+ char *lockfile = fmt("%s.lock", item->name);
+
+ top:
+ item->fd = open(lockfile, O_WRONLY | O_CREAT | O_EXCL, S_IRUSR|S_IWUSR);
+ if (item->fd == NOLOCK && errno == ENOENT && cache_create_dirs())
+ goto top;
+ if (item->fd == NOLOCK && errno == EEXIST) {
+ struct stat st;
+ time_t t;
+ if (stat(lockfile, &st))
+ return ret;
+ t = time(NULL);
+ if (t-st.st_mtime > cgit_cache_max_create_time &&
+ !unlink(lockfile))
+ goto top;
+ return 0;
+ }
+ return (item->fd > 0);
+}
+
+int cache_unlock(struct cacheitem *item)
+{
+ close(item->fd);
+ return (rename(fmt("%s.lock", item->name), item->name) == 0);
+}
+
+int cache_expired(struct cacheitem *item)
+{
+ if (item->ttl < 0)
+ return 0;
+ return item->st.st_mtime + item->ttl * 60 < time(NULL);
+}