6 files changed, 418 insertions, 210 deletions

diff --git a/cache.c b/cache.c
index 89f7ecd..e590d7b 100644
--- a/cache.c
+++ b/cache.c
@@ -1,120 +1,343 @@
 /* cache.c: cache management
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
+ *
+ *
+ * The cache is just a directory structure where each file is a cache slot,
+ * and each filename is based on the hash of some key (e.g. the cgit url).
+ * Each file contains the full key followed by the cached content for that
+ * key.
+ *
  */
 
 #include "cgit.h"
 #include "cache.h"
 
-const int NOLOCK = -1;
+#define CACHE_BUFSIZE (1024 * 4)
+
+struct cache_slot {
+        const char *key;
+        int keylen;
+        int ttl;
+        cache_fill_fn fn;
+        void *cbdata;
+        int cache_fd;
+        int lock_fd;
+        const char *cache_name;
+        const char *lock_name;
+        int match;
+        struct stat cache_st;
+        struct stat lock_st;
+        int bufsize;
+        char buf[CACHE_BUFSIZE];
+};
 
-char *cache_safe_filename(const char *unsafe)
+/* Open an existing cache slot and fill the cache buffer with
+ * (part of) the content of the cache file. Return 0 on success
+ * and errno otherwise.
+ */
+static int open_slot(struct cache_slot *slot)
 {
-        static char buf[4][PATH_MAX];
-        static int bufidx;
-        char *s;
-        char c;
-
-        bufidx++;
-        bufidx &= 3;
-        s = buf[bufidx];
-
-        while(unsafe && (c = *unsafe++) != 0) {
-                if (c == '/' || c == ' ' || c == '&' || c == '|' ||
-                    c == '>' || c == '<' || c == '.')
-                        c = '_';
-                *s++ = c;
-        }
-        *s = '\0';
-        return buf[bufidx];
+        char *bufz;
+        int bufkeylen = -1;
+
+        slot->cache_fd = open(slot->cache_name, O_RDONLY);
+        if (slot->cache_fd == -1)
+                return errno;
+
+        if (fstat(slot->cache_fd, &slot->cache_st))
+                return errno;
+
+        slot->bufsize = read(slot->cache_fd, slot->buf, sizeof(slot->buf));
+        if (slot->bufsize == 0)
+                return errno;
+
+        bufz = memchr(slot->buf, 0, slot->bufsize);
+        if (bufz)
+                bufkeylen = bufz - slot->buf;
+
+        slot->match = bufkeylen == slot->keylen &&
+            !memcmp(slot->key, slot->buf, bufkeylen + 1);
+
+        return 0;
 }
 
-int cache_exist(struct cacheitem *item)
+/* Close the active cache slot */
+static void close_slot(struct cache_slot *slot)
 {
-        if (stat(item->name, &item->st)) {
-                item->st.st_mtime = 0;
-                return 0;
+        if (slot->cache_fd > 0) {
+                close(slot->cache_fd);
+                slot->cache_fd = -1;
         }
-        return 1;
 }
 
-int cache_create_dirs()
+/* Print the content of the active cache slot (but skip the key). */
+static int print_slot(struct cache_slot *slot)
 {
-        char *path;
+        ssize_t i, j = 0;
+
+        i = lseek(slot->cache_fd, slot->keylen + 1, SEEK_SET);
+        if (i != slot->keylen + 1)
+                return errno;
 
-        path = fmt("%s", ctx.cfg.cache_root);
-        if (mkdir(path, S_IRWXU) && errno!=EEXIST)
+        while((i=read(slot->cache_fd, slot->buf, sizeof(slot->buf))) > 0)
+                j = write(STDOUT_FILENO, slot->buf, i);
+
+        if (j < 0)
+                return errno;
+        else
                 return 0;
+}
 
-        if (!ctx.repo)
+/* Check if the slot has expired */
+static int is_expired(struct cache_slot *slot)
+{
+        if (slot->ttl < 0)
                 return 0;
+        else
+                return slot->cache_st.st_mtime + slot->ttl*60 < time(NULL);
+}
 
-        path = fmt("%s/%s", ctx.cfg.cache_root,
-                   cache_safe_filename(ctx.repo->url));
+/* Check if the slot has been modified since we opened it.
+ * NB: If stat() fails, we pretend the file is modified.
+ */
+static int is_modified(struct cache_slot *slot)
+{
+        struct stat st;
 
-        if (mkdir(path, S_IRWXU) && errno!=EEXIST)
-                return 0;
+        if (stat(slot->cache_name, &st))
+                return 1;
+        return (st.st_ino != slot->cache_st.st_ino ||
+                st.st_mtime != slot->cache_st.st_mtime ||
+                st.st_size != slot->cache_st.st_size);
+}
 
-        if (ctx.qry.page) {
-                path = fmt("%s/%s/%s", ctx.cfg.cache_root,
-                           cache_safe_filename(ctx.repo->url),
-                           ctx.qry.page);
-                if (mkdir(path, S_IRWXU) && errno!=EEXIST)
-                        return 0;
+/* Close an open lockfile */
+static void close_lock(struct cache_slot *slot)
+{
+        if (slot->lock_fd > 0) {
+                close(slot->lock_fd);
+                slot->lock_fd = -1;
         }
-        return 1;
 }
 
-int cache_refill_overdue(const char *lockfile)
+/* Create a lockfile used to store the generated content for a cache
+ * slot, and write the slot key + \0 into it.
+ * Returns 0 on success and errno otherwise.
+ */
+static int lock_slot(struct cache_slot *slot)
 {
-        struct stat st;
+        slot->lock_fd = open(slot->lock_name, O_RDWR|O_CREAT|O_EXCL,
+                             S_IRUSR|S_IWUSR);
+        if (slot->lock_fd == -1)
+                return errno;
+        write(slot->lock_fd, slot->key, slot->keylen + 1);
+        return 0;
+}
 
-        if (stat(lockfile, &st))
-                return 0;
+/* Release the current lockfile. If `replace_old_slot` is set the
+ * lockfile replaces the old cache slot, otherwise the lockfile is
+ * just deleted.
+ */
+static int unlock_slot(struct cache_slot *slot, int replace_old_slot)
+{
+        int err;
+
+        if (replace_old_slot)
+                err = rename(slot->lock_name, slot->cache_name);
         else
-                return (time(NULL) - st.st_mtime > ctx.cfg.cache_max_create_time);
+                err = unlink(slot->lock_name);
+        return err;
 }
 
-int cache_lock(struct cacheitem *item)
+/* Generate the content for the current cache slot by redirecting
+ * stdout to the lock-fd and invoking the callback function
+ */
+static int fill_slot(struct cache_slot *slot)
 {
-        int i = 0;
-        char *lockfile = xstrdup(fmt("%s.lock", item->name));
+        int tmp;
 
- top:
-        if (++i > ctx.cfg.max_lock_attempts)
-                die("cache_lock: unable to lock %s: %s",
-                    item->name, strerror(errno));
+        /* Preserve stdout */
+        tmp = dup(STDOUT_FILENO);
+        if (tmp == -1)
+                return errno;
 
-               item->fd = open(lockfile, O_WRONLY|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR);
+        /* Redirect stdout to lockfile */
+        if (dup2(slot->lock_fd, STDOUT_FILENO) == -1)
+                return errno;
 
-        if (item->fd == NOLOCK && errno == ENOENT && cache_create_dirs())
-                goto top;
+        /* Generate cache content */
+        slot->fn(slot->cbdata);
 
-        if (item->fd == NOLOCK && errno == EEXIST &&
-            cache_refill_overdue(lockfile) && !unlink(lockfile))
-                        goto top;
+        /* Restore stdout */
+        if (dup2(tmp, STDOUT_FILENO) == -1)
+                return errno;
 
-        free(lockfile);
-        return (item->fd > 0);
+        /* Close the temporary filedescriptor */
+        close(tmp);
+        return 0;
 }
 
-int cache_unlock(struct cacheitem *item)
+/* Crude implementation of 32-bit FNV-1 hash algorithm,
+ * see http://www.isthe.com/chongo/tech/comp/fnv/ for details
+ * about the magic numbers.
+ */
+#define FNV_OFFSET 0x811c9dc5
+#define FNV_PRIME  0x01000193
+
+unsigned long hash_str(const char *str)
 {
-        close(item->fd);
-        return (rename(fmt("%s.lock", item->name), item->name) == 0);
+        unsigned long h = FNV_OFFSET;
+        unsigned char *s = (unsigned char *)str;
+
+        if (!s)
+                return h;
+
+        while(*s) {
+                h *= FNV_PRIME;
+                h ^= *s++;
+        }
+        return h;
 }
 
-int cache_cancel_lock(struct cacheitem *item)
+static int process_slot(struct cache_slot *slot)
 {
-        return (unlink(fmt("%s.lock", item->name)) == 0);
+        int err;
+
+        err = open_slot(slot);
+        if (!err && slot->match) {
+                if (is_expired(slot)) {
+                        if (!lock_slot(slot)) {
+                                /* If the cachefile has been replaced between
+                                 * `open_slot` and `lock_slot`, we'll just
+                                 * serve the stale content from the original
+                                 * cachefile. This way we avoid pruning the
+                                 * newly generated slot. The same code-path
+                                 * is chosen if fill_slot() fails for some
+                                 * reason.
+                                 *
+                                 * TODO? check if the new slot contains the
+                                 * same key as the old one, since we would
+                                 * prefer to serve the newest content.
+                                 * This will require us to open yet another
+                                 * file-descriptor and read and compare the
+                                 * key from the new file, so for now we're
+                                 * lazy and just ignore the new file.
+                                 */
+                                if (is_modified(slot) || fill_slot(slot)) {
+                                        unlock_slot(slot, 0);
+                                        close_lock(slot);
+                                } else {
+                                        close_slot(slot);
+                                        unlock_slot(slot, 1);
+                                        slot->cache_fd = slot->lock_fd;
+                                }
+                        }
+                }
+                print_slot(slot);
+                close_slot(slot);
+                return 0;
+        }
+
+        /* If the cache slot does not exist (or its key doesn't match the
+         * current key), lets try to create a new cache slot for this
+         * request. If this fails (for whatever reason), lets just generate
+         * the content without caching it and fool the caller to belive
+         * everything worked out (but print a warning on stdout).
+         */
+
+        close_slot(slot);
+        if ((err = lock_slot(slot)) != 0) {
+                cache_log("[cgit] Unable to lock slot %s: %s (%d)\n",
+                          slot->lock_name, strerror(err), err);
+                slot->fn(slot->cbdata);
+                return 0;
+        }
+
+        if ((err = fill_slot(slot)) != 0) {
+                cache_log("[cgit] Unable to fill slot %s: %s (%d)\n",
+                          slot->lock_name, strerror(err), err);
+                unlock_slot(slot, 0);
+                close_lock(slot);
+                slot->fn(slot->cbdata);
+                return 0;
+        }
+        // We've got a valid cache slot in the lock file, which
+        // is about to replace the old cache slot. But if we
+        // release the lockfile and then try to open the new cache
+        // slot, we might get a race condition with a concurrent
+        // writer for the same cache slot (with a different key).
+        // Lets avoid such a race by just printing the content of
+        // the lock file.
+        slot->cache_fd = slot->lock_fd;
+        unlock_slot(slot, 1);
+        err = print_slot(slot);
+        close_slot(slot);
+        return err;
 }
 
-int cache_expired(struct cacheitem *item)
+/* Print cached content to stdout, generate the content if necessary. */
+int cache_process(int size, const char *path, const char *key, int ttl,
+                  cache_fill_fn fn, void *cbdata)
 {
-        if (item->ttl < 0)
+        unsigned long hash;
+        int len, i;
+        char filename[1024];
+        char lockname[1024 + 5];  /* 5 = ".lock" */
+        struct cache_slot slot;
+
+        /* If the cache is disabled, just generate the content */
+        if (size <= 0) {
+                fn(cbdata);
                 return 0;
-        return item->st.st_mtime + item->ttl * 60 < time(NULL);
+        }
+
+        /* Verify input, calculate filenames */
+        if (!path) {
+                cache_log("[cgit] Cache path not specified, caching is disabled\n");
+                fn(cbdata);
+                return 0;
+        }
+        len = strlen(path);
+        if (len > sizeof(filename) - 10) { /* 10 = "/01234567\0" */
+                cache_log("[cgit] Cache path too long, caching is disabled: %s\n",
+                          path);
+                fn(cbdata);
+                return 0;
+        }
+        if (!key)
+                key = "";
+        hash = hash_str(key) % size;
+        strcpy(filename, path);
+        if (filename[len - 1] != '/')
+                filename[len++] = '/';
+        for(i = 0; i < 8; i++) {
+                sprintf(filename + len++, "%x",
+                        (unsigned char)(hash & 0xf));
+                hash >>= 4;
+        }
+        filename[len] = '\0';
+        strcpy(lockname, filename);
+        strcpy(lockname + len, ".lock");
+        slot.fn = fn;
+        slot.cbdata = cbdata;
+        slot.ttl = ttl;
+        slot.cache_name = filename;
+        slot.lock_name = lockname;
+        slot.key = key;
+        slot.keylen = strlen(key);
+        return process_slot(&slot);
 }
+
+/* Print a message to stdout */
+void cache_log(const char *format, ...)
+{
+        va_list args;
+        va_start(args, format);
+        vfprintf(stderr, format, args);
+        va_end(args);
+}
+
diff --git a/cache.h b/cache.h
index 4dcbea3..5f2178d 100644
--- a/cache.h
+++ b/cache.h
@@ -1,23 +1,32 @@
 /*
  * Since git has it's own cache.h which we include,
  * lets test on CGIT_CACHE_H to avoid confusion
  */
 
 #ifndef CGIT_CACHE_H
 #define CGIT_CACHE_H
 
-struct cacheitem {
-        char *name;
-        struct stat st;
-        int ttl;
-        int fd;
-};
+typedef void (*cache_fill_fn)(void *cbdata);
 
-extern char *cache_safe_filename(const char *unsafe);
-extern int cache_lock(struct cacheitem *item);
-extern int cache_unlock(struct cacheitem *item);
-extern int cache_cancel_lock(struct cacheitem *item);
-extern int cache_exist(struct cacheitem *item);
-extern int cache_expired(struct cacheitem *item);
+
+/* Print cached content to stdout, generate the content if necessary.
+ *
+ * Parameters
+ *   size    max number of cache files
+ *   path    directory used to store cache files
+ *   key     the key used to lookup cache files
+ *   ttl     max cache time in seconds for this key
+ *   fn      content generator function for this key
+ *   cbdata  user-supplied data to the content generator function
+ *
+ * Return value
+ *   0 indicates success, everyting else is an error
+ */
+extern int cache_process(int size, const char *path, const char *key, int ttl,
+                         cache_fill_fn fn, void *cbdata);
+
+
+/* Print a message to stdout */
+extern void cache_log(const char *format, ...);
 
 #endif /* CGIT_CACHE_H */
diff --git a/cgit.c b/cgit.c
index 38b0ba5..4dc8eec 100644
--- a/cgit.c
+++ b/cgit.c
@@ -1,95 +1,97 @@
 /* cgit.c: cgi for the git scm
  *
  * Copyright (C) 2006 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 #include "cache.h"
 #include "cmd.h"
 #include "configfile.h"
 #include "html.h"
 #include "ui-shared.h"
 
 const char *cgit_version = CGIT_VERSION;
 
 void config_cb(const char *name, const char *value)
 {
         if (!strcmp(name, "root-title"))
                 ctx.cfg.root_title = xstrdup(value);
         else if (!strcmp(name, "css"))
                 ctx.cfg.css = xstrdup(value);
         else if (!strcmp(name, "logo"))
                 ctx.cfg.logo = xstrdup(value);
         else if (!strcmp(name, "index-header"))
                 ctx.cfg.index_header = xstrdup(value);
         else if (!strcmp(name, "index-info"))
                 ctx.cfg.index_info = xstrdup(value);
         else if (!strcmp(name, "logo-link"))
                 ctx.cfg.logo_link = xstrdup(value);
         else if (!strcmp(name, "module-link"))
                 ctx.cfg.module_link = xstrdup(value);
         else if (!strcmp(name, "virtual-root")) {
                 ctx.cfg.virtual_root = trim_end(value, '/');
                 if (!ctx.cfg.virtual_root && (!strcmp(value, "/")))
                         ctx.cfg.virtual_root = "";
         } else if (!strcmp(name, "nocache"))
                 ctx.cfg.nocache = atoi(value);
         else if (!strcmp(name, "snapshots"))
                 ctx.cfg.snapshots = cgit_parse_snapshots_mask(value);
         else if (!strcmp(name, "enable-index-links"))
                 ctx.cfg.enable_index_links = atoi(value);
         else if (!strcmp(name, "enable-log-filecount"))
                 ctx.cfg.enable_log_filecount = atoi(value);
         else if (!strcmp(name, "enable-log-linecount"))
                 ctx.cfg.enable_log_linecount = atoi(value);
+        else if (!strcmp(name, "cache-size"))
+                ctx.cfg.cache_size = atoi(value);
         else if (!strcmp(name, "cache-root"))
                 ctx.cfg.cache_root = xstrdup(value);
         else if (!strcmp(name, "cache-root-ttl"))
                 ctx.cfg.cache_root_ttl = atoi(value);
         else if (!strcmp(name, "cache-repo-ttl"))
                 ctx.cfg.cache_repo_ttl = atoi(value);
         else if (!strcmp(name, "cache-static-ttl"))
                 ctx.cfg.cache_static_ttl = atoi(value);
         else if (!strcmp(name, "cache-dynamic-ttl"))
                 ctx.cfg.cache_dynamic_ttl = atoi(value);
         else if (!strcmp(name, "max-message-length"))
                 ctx.cfg.max_msg_len = atoi(value);
         else if (!strcmp(name, "max-repodesc-length"))
                 ctx.cfg.max_repodesc_len = atoi(value);
         else if (!strcmp(name, "max-commit-count"))
                 ctx.cfg.max_commit_count = atoi(value);
         else if (!strcmp(name, "summary-log"))
                 ctx.cfg.summary_log = atoi(value);
         else if (!strcmp(name, "summary-branches"))
                 ctx.cfg.summary_branches = atoi(value);
         else if (!strcmp(name, "summary-tags"))
                 ctx.cfg.summary_tags = atoi(value);
         else if (!strcmp(name, "agefile"))
                 ctx.cfg.agefile = xstrdup(value);
         else if (!strcmp(name, "renamelimit"))
                 ctx.cfg.renamelimit = atoi(value);
         else if (!strcmp(name, "robots"))
                 ctx.cfg.robots = xstrdup(value);
         else if (!strcmp(name, "clone-prefix"))
                 ctx.cfg.clone_prefix = xstrdup(value);
         else if (!strcmp(name, "repo.group"))
                 ctx.cfg.repo_group = xstrdup(value);
         else if (!strcmp(name, "repo.url"))
                 ctx.repo = cgit_add_repo(value);
         else if (!strcmp(name, "repo.name"))
                 ctx.repo->name = xstrdup(value);
         else if (ctx.repo && !strcmp(name, "repo.path"))
                 ctx.repo->path = trim_end(value, '/');
         else if (ctx.repo && !strcmp(name, "repo.clone-url"))
                 ctx.repo->clone_url = xstrdup(value);
         else if (ctx.repo && !strcmp(name, "repo.desc"))
                 ctx.repo->desc = xstrdup(value);
         else if (ctx.repo && !strcmp(name, "repo.owner"))
                 ctx.repo->owner = xstrdup(value);
         else if (ctx.repo && !strcmp(name, "repo.defbranch"))
                 ctx.repo->defbranch = xstrdup(value);
         else if (ctx.repo && !strcmp(name, "repo.snapshots"))
                 ctx.repo->snapshots = ctx.cfg.snapshots & cgit_parse_snapshots_mask(value); /* XXX: &? */
@@ -98,364 +100,270 @@ void config_cb(const char *name, const char *value)
         else if (ctx.repo && !strcmp(name, "repo.enable-log-linecount"))
                 ctx.repo->enable_log_linecount = ctx.cfg.enable_log_linecount * atoi(value);
         else if (ctx.repo && !strcmp(name, "repo.module-link"))
                 ctx.repo->module_link= xstrdup(value);
         else if (ctx.repo && !strcmp(name, "repo.readme") && value != NULL) {
                 if (*value == '/')
                         ctx.repo->readme = xstrdup(value);
                 else
                         ctx.repo->readme = xstrdup(fmt("%s/%s", ctx.repo->path, value));
         } else if (!strcmp(name, "include"))
                 parse_configfile(value, config_cb);
 }
 
 static void querystring_cb(const char *name, const char *value)
 {
         if (!strcmp(name,"r")) {
                 ctx.qry.repo = xstrdup(value);
                 ctx.repo = cgit_get_repoinfo(value);
         } else if (!strcmp(name, "p")) {
                 ctx.qry.page = xstrdup(value);
         } else if (!strcmp(name, "url")) {
                 cgit_parse_url(value);
         } else if (!strcmp(name, "qt")) {
                 ctx.qry.grep = xstrdup(value);
         } else if (!strcmp(name, "q")) {
                 ctx.qry.search = xstrdup(value);
         } else if (!strcmp(name, "h")) {
                 ctx.qry.head = xstrdup(value);
                 ctx.qry.has_symref = 1;
         } else if (!strcmp(name, "id")) {
                 ctx.qry.sha1 = xstrdup(value);
                 ctx.qry.has_sha1 = 1;
         } else if (!strcmp(name, "id2")) {
                 ctx.qry.sha2 = xstrdup(value);
                 ctx.qry.has_sha1 = 1;
         } else if (!strcmp(name, "ofs")) {
                 ctx.qry.ofs = atoi(value);
         } else if (!strcmp(name, "path")) {
                 ctx.qry.path = trim_end(value, '/');
         } else if (!strcmp(name, "name")) {
                 ctx.qry.name = xstrdup(value);
         }
 }
 
 static void prepare_context(struct cgit_context *ctx)
 {
         memset(ctx, 0, sizeof(ctx));
         ctx->cfg.agefile = "info/web/last-modified";
+        ctx->cfg.nocache = 0;
+        ctx->cfg.cache_size = 0;
         ctx->cfg.cache_dynamic_ttl = 5;
         ctx->cfg.cache_max_create_time = 5;
         ctx->cfg.cache_repo_ttl = 5;
         ctx->cfg.cache_root = CGIT_CACHE_ROOT;
         ctx->cfg.cache_root_ttl = 5;
         ctx->cfg.cache_static_ttl = -1;
         ctx->cfg.css = "/cgit.css";
         ctx->cfg.logo = "/git-logo.png";
         ctx->cfg.max_commit_count = 50;
         ctx->cfg.max_lock_attempts = 5;
         ctx->cfg.max_msg_len = 60;
         ctx->cfg.max_repodesc_len = 60;
         ctx->cfg.module_link = "./?repo=%s&page=commit&id=%s";
         ctx->cfg.renamelimit = -1;
         ctx->cfg.robots = "index, nofollow";
         ctx->cfg.root_title = "Git repository browser";
         ctx->cfg.script_name = CGIT_SCRIPT_NAME;
         ctx->page.mimetype = "text/html";
         ctx->page.charset = PAGE_ENCODING;
         ctx->page.filename = NULL;
-}
-
-static int cgit_prepare_cache(struct cacheitem *item)
-{
-        if (!ctx.repo && ctx.qry.repo) {
-                ctx.page.title = fmt("%s - %s", ctx.cfg.root_title,
-                                      "Bad request");
-                cgit_print_http_headers(&ctx);
-                cgit_print_docstart(&ctx);
-                cgit_print_pageheader(&ctx);
-                cgit_print_error(fmt("Unknown repo: %s", ctx.qry.repo));
-                cgit_print_docend();
-                return 0;
-        }
-
-        if (!ctx.repo) {
-                item->name = xstrdup(fmt("%s/index.%s.html",
-                                         ctx.cfg.cache_root,
-                                         cache_safe_filename(ctx.qry.raw)));
-                item->ttl = ctx.cfg.cache_root_ttl;
-                return 1;
-        }
-
-        if (!ctx.qry.page) {
-                item->name = xstrdup(fmt("%s/%s/index.%s.html", ctx.cfg.cache_root,
-                                         cache_safe_filename(ctx.repo->url),
-                                         cache_safe_filename(ctx.qry.raw)));
-                item->ttl = ctx.cfg.cache_repo_ttl;
-        } else {
-                item->name = xstrdup(fmt("%s/%s/%s/%s.html", ctx.cfg.cache_root,
-                                         cache_safe_filename(ctx.repo->url),
-                                         ctx.qry.page,
-                                         cache_safe_filename(ctx.qry.raw)));
-                if (ctx.qry.has_symref)
-                        item->ttl = ctx.cfg.cache_dynamic_ttl;
-                else if (ctx.qry.has_sha1)
-                        item->ttl = ctx.cfg.cache_static_ttl;
-                else
-                        item->ttl = ctx.cfg.cache_repo_ttl;
-        }
-        return 1;
+        ctx->page.modified = time(NULL);
+        ctx->page.expires = ctx->page.modified;
 }
 
 struct refmatch {
         char *req_ref;
         char *first_ref;
         int match;
 };
 
 int find_current_ref(const char *refname, const unsigned char *sha1,
                      int flags, void *cb_data)
 {
         struct refmatch *info;
 
         info = (struct refmatch *)cb_data;
         if (!strcmp(refname, info->req_ref))
                 info->match = 1;
         if (!info->first_ref)
                 info->first_ref = xstrdup(refname);
         return info->match;
 }
 
 char *find_default_branch(struct cgit_repo *repo)
 {
         struct refmatch info;
 
         info.req_ref = repo->defbranch;
         info.first_ref = NULL;
         info.match = 0;
         for_each_branch_ref(find_current_ref, &info);
         if (info.match)
                 return info.req_ref;
         else
                 return info.first_ref;
 }
 
 static int prepare_repo_cmd(struct cgit_context *ctx)
 {
         char *tmp;
         unsigned char sha1[20];
         int nongit = 0;
 
         setenv("GIT_DIR", ctx->repo->path, 1);
         setup_git_directory_gently(&nongit);
         if (nongit) {
                 ctx->page.title = fmt("%s - %s", ctx->cfg.root_title,
                                       "config error");
                 tmp = fmt("Not a git repository: '%s'", ctx->repo->path);
                 ctx->repo = NULL;
                 cgit_print_http_headers(ctx);
                 cgit_print_docstart(ctx);
                 cgit_print_pageheader(ctx);
                 cgit_print_error(tmp);
                 cgit_print_docend();
                 return 1;
         }
         ctx->page.title = fmt("%s - %s", ctx->repo->name, ctx->repo->desc);
 
         if (!ctx->qry.head) {
                 ctx->qry.head = xstrdup(find_default_branch(ctx->repo));
                 ctx->repo->defbranch = ctx->qry.head;
         }
 
         if (!ctx->qry.head) {
                 cgit_print_http_headers(ctx);
                 cgit_print_docstart(ctx);
                 cgit_print_pageheader(ctx);
                 cgit_print_error("Repository seems to be empty");
                 cgit_print_docend();
                 return 1;
         }
 
         if (get_sha1(ctx->qry.head, sha1)) {
                 tmp = xstrdup(ctx->qry.head);
                 ctx->qry.head = ctx->repo->defbranch;
                 cgit_print_http_headers(ctx);
                 cgit_print_docstart(ctx);
                 cgit_print_pageheader(ctx);
                 cgit_print_error(fmt("Invalid branch: %s", tmp));
                 cgit_print_docend();
                 return 1;
         }
         return 0;
 }
 
-static void process_request(struct cgit_context *ctx)
+static void process_request(void *cbdata)
 {
+        struct cgit_context *ctx = cbdata;
         struct cgit_cmd *cmd;
 
         cmd = cgit_get_cmd(ctx);
         if (!cmd) {
                 ctx->page.title = "cgit error";
                 ctx->repo = NULL;
                 cgit_print_http_headers(ctx);
                 cgit_print_docstart(ctx);
                 cgit_print_pageheader(ctx);
                 cgit_print_error("Invalid request");
                 cgit_print_docend();
                 return;
         }
 
         if (cmd->want_repo && prepare_repo_cmd(ctx))
                 return;
 
         if (cmd->want_layout) {
                 cgit_print_http_headers(ctx);
                 cgit_print_docstart(ctx);
                 cgit_print_pageheader(ctx);
         }
 
         cmd->fn(ctx);
 
         if (cmd->want_layout)
                 cgit_print_docend();
 }
 
-static long ttl_seconds(long ttl)
-{
-        if (ttl<0)
-                return 60 * 60 * 24 * 365;
-        else
-                return ttl * 60;
-}
-
-static void cgit_fill_cache(struct cacheitem *item, int use_cache)
-{
-        int stdout2;
-
-        if (use_cache) {
-                stdout2 = chk_positive(dup(STDOUT_FILENO),
-                                       "Preserving STDOUT");
-                chk_zero(close(STDOUT_FILENO), "Closing STDOUT");
-                chk_positive(dup2(item->fd, STDOUT_FILENO), "Dup2(cachefile)");
-        }
-
-        ctx.page.modified = time(NULL);
-        ctx.page.expires = ctx.page.modified + ttl_seconds(item->ttl);
-        process_request(&ctx);
-
-        if (use_cache) {
-                chk_zero(close(STDOUT_FILENO), "Close redirected STDOUT");
-                chk_positive(dup2(stdout2, STDOUT_FILENO),
-                             "Restoring original STDOUT");
-                chk_zero(close(stdout2), "Closing temporary STDOUT");
-        }
-}
-
-static void cgit_check_cache(struct cacheitem *item)
-{
-        int i = 0;
-
- top:
-        if (++i > ctx.cfg.max_lock_attempts) {
-                die("cgit_refresh_cache: unable to lock %s: %s",
-                    item->name, strerror(errno));
-        }
-        if (!cache_exist(item)) {
-                if (!cache_lock(item)) {
-                        sleep(1);
-                        goto top;
-                }
-                if (!cache_exist(item)) {
-                        cgit_fill_cache(item, 1);
-                        cache_unlock(item);
-                } else {
-                        cache_cancel_lock(item);
-                }
-        } else if (cache_expired(item) && cache_lock(item)) {
-                if (cache_expired(item)) {
-                        cgit_fill_cache(item, 1);
-                        cache_unlock(item);
-                } else {
-                        cache_cancel_lock(item);
-                }
-        }
-}
-
-static void cgit_print_cache(struct cacheitem *item)
-{
-        static char buf[4096];
-        ssize_t i;
-
-        int fd = open(item->name, O_RDONLY);
-        if (fd<0)
-                die("Unable to open cached file %s", item->name);
-
-        while((i=read(fd, buf, sizeof(buf))) > 0)
-                write(STDOUT_FILENO, buf, i);
-
-        close(fd);
-}
-
 static void cgit_parse_args(int argc, const char **argv)
 {
         int i;
 
         for (i = 1; i < argc; i++) {
                 if (!strncmp(argv[i], "--cache=", 8)) {
                         ctx.cfg.cache_root = xstrdup(argv[i]+8);
                 }
                 if (!strcmp(argv[i], "--nocache")) {
                         ctx.cfg.nocache = 1;
                 }
                 if (!strncmp(argv[i], "--query=", 8)) {
                         ctx.qry.raw = xstrdup(argv[i]+8);
                 }
                 if (!strncmp(argv[i], "--repo=", 7)) {
                         ctx.qry.repo = xstrdup(argv[i]+7);
                 }
                 if (!strncmp(argv[i], "--page=", 7)) {
                         ctx.qry.page = xstrdup(argv[i]+7);
                 }
                 if (!strncmp(argv[i], "--head=", 7)) {
                         ctx.qry.head = xstrdup(argv[i]+7);
                         ctx.qry.has_symref = 1;
                 }
                 if (!strncmp(argv[i], "--sha1=", 7)) {
                         ctx.qry.sha1 = xstrdup(argv[i]+7);
                         ctx.qry.has_sha1 = 1;
                 }
                 if (!strncmp(argv[i], "--ofs=", 6)) {
                         ctx.qry.ofs = atoi(argv[i]+6);
                 }
         }
 }
 
+static int calc_ttl()
+{
+        if (!ctx.repo)
+                return ctx.cfg.cache_root_ttl;
+
+        if (!ctx.qry.page)
+                return ctx.cfg.cache_repo_ttl;
+
+        if (ctx.qry.has_symref)
+                return ctx.cfg.cache_dynamic_ttl;
+
+        if (ctx.qry.has_sha1)
+                return ctx.cfg.cache_static_ttl;
+
+        return ctx.cfg.cache_repo_ttl;
+}
+
 int main(int argc, const char **argv)
 {
-        struct cacheitem item;
         const char *cgit_config_env = getenv("CGIT_CONFIG");
+        int err, ttl;
 
         prepare_context(&ctx);
-        item.st.st_mtime = time(NULL);
         cgit_repolist.length = 0;
         cgit_repolist.count = 0;
         cgit_repolist.repos = NULL;
 
         parse_configfile(cgit_config_env ? cgit_config_env : CGIT_CONFIG,
                          config_cb);
         ctx.repo = NULL;
         if (getenv("SCRIPT_NAME"))
                 ctx.cfg.script_name = xstrdup(getenv("SCRIPT_NAME"));
         if (getenv("QUERY_STRING"))
                 ctx.qry.raw = xstrdup(getenv("QUERY_STRING"));
         cgit_parse_args(argc, argv);
         http_parse_querystring(ctx.qry.raw, querystring_cb);
-        if (!cgit_prepare_cache(&item))
-                return 0;
-        if (ctx.cfg.nocache) {
-                cgit_fill_cache(&item, 0);
-        } else {
-                cgit_check_cache(&item);
-                cgit_print_cache(&item);
-        }
-        return 0;
+
+        ttl = calc_ttl();
+        ctx.page.expires += ttl*60;
+        if (ctx.cfg.nocache)
+                ctx.cfg.cache_size = 0;
+        err = cache_process(ctx.cfg.cache_size, ctx.cfg.cache_root,
+                            ctx.qry.raw, ttl, process_request, &ctx);
+        if (err)
+                cache_log("[cgit] error %d - %s\n",
+                          err, strerror(err));
+        return err;
 }
diff --git a/cgit.h b/cgit.h
index a3b6535..f04d227 100644
--- a/cgit.h
+++ b/cgit.h
@@ -89,96 +89,97 @@ struct taginfo {
 };
 
 struct refinfo {
         const char *refname;
         struct object *object;
         union {
                 struct taginfo *tag;
                 struct commitinfo *commit;
         };
 };
 
 struct reflist {
         struct refinfo **refs;
         int alloc;
         int count;
 };
 
 struct cgit_query {
         int has_symref;
         int has_sha1;
         char *raw;
         char *repo;
         char *page;
         char *search;
         char *grep;
         char *head;
         char *sha1;
         char *sha2;
         char *path;
         char *name;
         int   ofs;
 };
 
 struct cgit_config {
         char *agefile;
         char *cache_root;
         char *clone_prefix;
         char *css;
         char *index_header;
         char *index_info;
         char *logo;
         char *logo_link;
         char *module_link;
         char *repo_group;
         char *robots;
         char *root_title;
         char *script_name;
         char *virtual_root;
+        int cache_size;
         int cache_dynamic_ttl;
         int cache_max_create_time;
         int cache_repo_ttl;
         int cache_root_ttl;
         int cache_static_ttl;
         int enable_index_links;
         int enable_log_filecount;
         int enable_log_linecount;
         int max_commit_count;
         int max_lock_attempts;
         int max_msg_len;
         int max_repodesc_len;
         int nocache;
         int renamelimit;
         int snapshots;
         int summary_branches;
         int summary_log;
         int summary_tags;
 };
 
 struct cgit_page {
         time_t modified;
         time_t expires;
         char *mimetype;
         char *charset;
         char *filename;
         char *title;
 };
 
 struct cgit_context {
         struct cgit_query qry;
         struct cgit_config cfg;
         struct cgit_repo *repo;
         struct cgit_page page;
 };
 
 struct cgit_snapshot_format {
         const char *suffix;
         const char *mimetype;
         write_archive_fn_t write_func;
         int bit;
 };
 
 extern const char *cgit_version;
 
 extern struct cgit_repolist cgit_repolist;
 extern struct cgit_context ctx;
 extern const struct cgit_snapshot_format cgit_snapshot_formats[];
diff --git a/tests/setup.sh b/tests/setup.sh
index 66bf406..e37306e 100755
--- a/tests/setup.sh
+++ b/tests/setup.sh
@@ -1,95 +1,95 @@
 # This file should be sourced by all test-scripts
 #
 # Main functions:
 #   prepare_tests(description) - setup for testing, i.e. create repos+config
 #   run_test(description, script) - run one test, i.e. eval script
 #
 # Helper functions
 #   cgit_query(querystring) - call cgit with the specified querystring
 #   cgit_url(url) - call cgit with the specified virtual url
 #
 # Example script:
 #
 # . setup.sh
 # prepare_tests "html validation"
 # run_test 'repo index' 'cgit_url "/" | tidy -e'
 # run_test 'repo summary' 'cgit_url "/foo" | tidy -e'
 
 
 mkrepo() {
         name=$1
         count=$2
         dir=$PWD
         test -d $name && return
         printf "Creating testrepo %s\n" $name
         mkdir -p $name
         cd $name
         git init
         for ((n=1; n<=count; n++))
         do
                 echo $n >file-$n
                 git add file-$n
                 git commit -m "commit $n"
         done
         cd $dir
 }
 
 setup_repos()
 {
         rm -rf trash/cache
         mkdir -p trash/cache
         mkrepo trash/repos/foo 5 >/dev/null
         mkrepo trash/repos/bar 50 >/dev/null
         cat >trash/cgitrc <<EOF
 virtual-root=/
 cache-root=$PWD/trash/cache
 
-nocache=0
+cache-size=1021
 snapshots=tar.gz tar.bz zip
 enable-log-filecount=1
 enable-log-linecount=1
 summary-log=5
 summary-branches=5
 summary-tags=5
 
 repo.url=foo
 repo.path=$PWD/trash/repos/foo/.git
 # Do not specify a description for this repo, as it then will be assigned
 # the constant value "[no description]" (which actually used to cause a
 # segfault).
 
 repo.url=bar
 repo.path=$PWD/trash/repos/bar/.git
 repo.desc=the bar repo
 EOF
 }
 
 prepare_tests()
 {
         setup_repos
         rm -f test-output.log 2>/dev/null
         test_count=0
         test_failed=0
         echo "[$0]" "$@" >test-output.log
         echo "$@" "($0)"
 }
 
 tests_done()
 {
         printf "\n"
         if test $test_failed -gt 0
         then
                 printf "test: *** %s failure(s), logfile=%s\n" \
                         $test_failed "$(pwd)/test-output.log"
                 false
         fi
 }
 
 run_test()
 {
         desc=$1
         script=$2
         ((test_count++))
         printf "\ntest %d: name='%s'\n" $test_count "$desc" >>test-output.log
         printf "test %d: eval='%s'\n" $test_count "$2" >>test-output.log
         eval "$2" >>test-output.log 2>>test-output.log
diff --git a/tests/t0020-validate-cache.sh b/tests/t0020-validate-cache.sh
new file mode 100755
index 0000000..53ec2eb
--- a/dev/null
+++ b/tests/t0020-validate-cache.sh
@@ -0,0 +1,67 @@
+#!/bin/sh
+
+. ./setup.sh
+
+prepare_tests 'Validate cache'
+
+run_test 'verify cache-size=0' '
+
+        rm -f trash/cache/* &&
+        sed -i -e "s/cache-size=1021$/cache-size=0/" trash/cgitrc &&
+        cgit_url "" &&
+        cgit_url "foo" &&
+        cgit_url "foo/refs" &&
+        cgit_url "foo/tree" &&
+        cgit_url "foo/log" &&
+        cgit_url "foo/diff" &&
+        cgit_url "foo/patch" &&
+        cgit_url "bar" &&
+        cgit_url "bar/refs" &&
+        cgit_url "bar/tree" &&
+        cgit_url "bar/log" &&
+        cgit_url "bar/diff" &&
+        cgit_url "bar/patch" &&
+        test 0 -eq $(ls trash/cache | wc -l)
+'
+
+run_test 'verify cache-size=1' '
+
+        rm -f trash/cache/* &&
+        sed -i -e "s/cache-size=0$/cache-size=1/" trash/cgitrc &&
+        cgit_url "" &&
+        cgit_url "foo" &&
+        cgit_url "foo/refs" &&
+        cgit_url "foo/tree" &&
+        cgit_url "foo/log" &&
+        cgit_url "foo/diff" &&
+        cgit_url "foo/patch" &&
+        cgit_url "bar" &&
+        cgit_url "bar/refs" &&
+        cgit_url "bar/tree" &&
+        cgit_url "bar/log" &&
+        cgit_url "bar/diff" &&
+        cgit_url "bar/patch" &&
+        test 1 -eq $(ls trash/cache | wc -l)
+'
+
+run_test 'verify cache-size=1021' '
+
+        rm -f trash/cache/* &&
+        sed -i -e "s/cache-size=1$/cache-size=1021/" trash/cgitrc &&
+        cgit_url "" &&
+        cgit_url "foo" &&
+        cgit_url "foo/refs" &&
+        cgit_url "foo/tree" &&
+        cgit_url "foo/log" &&
+        cgit_url "foo/diff" &&
+        cgit_url "foo/patch" &&
+        cgit_url "bar" &&
+        cgit_url "bar/refs" &&
+        cgit_url "bar/tree" &&
+        cgit_url "bar/log" &&
+        cgit_url "bar/diff" &&
+        cgit_url "bar/patch" &&
+        test 13 -eq $(ls trash/cache | wc -l)
+'
+
+tests_done