Fix cache algorithm loophole

This closes the door for unneccessary calls to cgit_fill_cache().

Noticed by Linus.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

diff --git a/cache.c b/cache.c
index b034c480e0d9866de93bfa3866abda0cb0bd7df5..0ffa502c119ae33deaac913eabb742679cf4fe18 100644 (file)
--- a/cache.c
+++ b/cache.c
@@ -10,7 +10,7 @@
 
 const int NOLOCK = -1;
 
-int cache_lookup(struct cacheitem *item)
+void cache_prepare(struct cacheitem *item)
 {
        if (!cgit_query_repo) {
                item->name = xstrdup(fmt("%s/index.html", cgit_cache_root));
@@ -30,6 +30,10 @@ int cache_lookup(struct cacheitem *item)
                else
                        item->ttl = cgit_cache_repo_ttl;
        }
+}
+
+int cache_exist(struct cacheitem *item)
+{
        if (stat(item->name, &item->st)) {
                item->st.st_mtime = 0;
                return 0;

diff --git a/cgit.c b/cgit.c
index 110facec5867ad0912da6b41c24758a6c3f798cf..7f14016fb70ecb380ffafaa3e7f9f8d92fb362c5 100644 (file)
--- a/cgit.c
+++ b/cgit.c
@@ -465,20 +465,20 @@ static void cgit_fill_cache(struct cacheitem *item)
 
 static void cgit_refresh_cache(struct cacheitem *item)
 {
+       cache_prepare(item);
  top:
-       if (!cache_lookup(item)) {
-               if (cache_lock(item)) {
-                       cgit_fill_cache(item);
-                       cache_unlock(item);
-               } else {
+       if (!cache_exist(item)) {
+               if (!cache_lock(item)) {
                        sched_yield();
                        goto top;
                }
-       } else if (cache_expired(item)) {
-               if (cache_lock(item)) {
+               if (!cache_exist(item))
                        cgit_fill_cache(item);
-                       cache_unlock(item);
-               }
+               cache_unlock(item);
+       } else if (cache_expired(item) && cache_lock(item)) {
+               if (cache_expired(item))
+                       cgit_fill_cache(item);
+               cache_unlock(item);
        }
 }
 

diff --git a/cgit.h b/cgit.h
index 1e084d4cb02f743d2b4c014ce69b9a8cacad491f..3b0994a775492f652359ff45f7342c7787f9dc44 100644 (file)
--- a/cgit.h
+++ b/cgit.h
@@ -56,9 +56,10 @@ extern void html_link_close(void);
 
 extern int cgit_read_config(const char *filename, configfn fn);
 
-extern int cache_lookup(struct cacheitem *item);
+extern void cache_prepare(struct cacheitem *item);
 extern int cache_lock(struct cacheitem *item);
 extern int cache_unlock(struct cacheitem *item);
+extern int cache_exist(struct cacheitem *item);
 extern int cache_expired(struct cacheitem *item);
 
 #endif /* CGIT_H */