1 file 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);
+}