Add page 'ls_cache'

This new page will list all entries found in the current cache, which is
useful when reviewing the new cache implementation. There are no links to
the new page, but it's reachable by adding 'p=ls_cache' to any cgit url.

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

3 files changed, 87 insertions, 5 deletions

diff --git a/cache.c b/cache.c
index e590d7b..b701e13 100644
--- a/cache.c
+++ b/cache.c
@@ -1,343 +1,411 @@
 /* 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"
 
 #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];
 };
 
 /* 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)
 {
         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;
 }
 
 /* Close the active cache slot */
 static void close_slot(struct cache_slot *slot)
 {
         if (slot->cache_fd > 0) {
                 close(slot->cache_fd);
                 slot->cache_fd = -1;
         }
 }
 
 /* Print the content of the active cache slot (but skip the key). */
 static int print_slot(struct cache_slot *slot)
 {
         ssize_t i, j = 0;
 
         i = lseek(slot->cache_fd, slot->keylen + 1, SEEK_SET);
         if (i != slot->keylen + 1)
                 return errno;
 
         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;
 }
 
 /* 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);
 }
 
 /* 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 (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);
 }
 
 /* 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;
         }
 }
 
 /* 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)
 {
         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;
 }
 
 /* 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
                 err = unlink(slot->lock_name);
         return err;
 }
 
 /* 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 tmp;
 
         /* Preserve stdout */
         tmp = dup(STDOUT_FILENO);
         if (tmp == -1)
                 return errno;
 
         /* Redirect stdout to lockfile */
         if (dup2(slot->lock_fd, STDOUT_FILENO) == -1)
                 return errno;
 
         /* Generate cache content */
         slot->fn(slot->cbdata);
 
         /* Restore stdout */
         if (dup2(tmp, STDOUT_FILENO) == -1)
                 return errno;
 
         /* Close the temporary filedescriptor */
         close(tmp);
         return 0;
 }
 
 /* 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)
 {
         unsigned long h = FNV_OFFSET;
         unsigned char *s = (unsigned char *)str;
 
         if (!s)
                 return h;
 
         while(*s) {
                 h *= FNV_PRIME;
                 h ^= *s++;
         }
         return h;
 }
 
 static int process_slot(struct cache_slot *slot)
 {
         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;
 }
 
 /* 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)
 {
         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;
         }
 
         /* 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);
 }
 
+/* Return a strftime formatted date/time
+ * NB: the result from this function is to shared memory
+ */
+char *sprintftime(const char *format, time_t time)
+{
+        static char buf[64];
+        struct tm *tm;
+
+        if (!time)
+                return NULL;
+        tm = gmtime(&time);
+        strftime(buf, sizeof(buf)-1, format, tm);
+        return buf;
+}
+
+int cache_ls(const char *path)
+{
+        DIR *dir;
+        struct dirent *ent;
+        int err = 0;
+        struct cache_slot slot;
+        char fullname[1024];
+        char *name;
+
+        if (!path) {
+                cache_log("[cgit] cache path not specified\n");
+                return -1;
+        }
+        if (strlen(path) > 1024 - 10) {
+                cache_log("[cgit] cache path too long: %s\n",
+                          path);
+                return -1;
+        }
+        dir = opendir(path);
+        if (!dir) {
+                err = errno;
+                cache_log("[cgit] unable to open path %s: %s (%d)\n",
+                          path, strerror(err), err);
+                return err;
+        }
+        strcpy(fullname, path);
+        name = fullname + strlen(path);
+        if (*(name - 1) != '/') {
+                *name++ = '/';
+                *name = '\0';
+        }
+        slot.cache_name = fullname;
+        while((ent = readdir(dir)) != NULL) {
+                if (strlen(ent->d_name) != 8)
+                        continue;
+                strcpy(name, ent->d_name);
+                if ((err = open_slot(&slot)) != 0) {
+                        cache_log("[cgit] unable to open path %s: %s (%d)\n",
+                                  fullname, strerror(err), err);
+                        continue;
+                }
+                printf("%s %s %10lld %s\n",
+                       name,
+                       sprintftime("%Y-%m-%d %H:%M:%S",
+                                   slot.cache_st.st_mtime),
+                       slot.cache_st.st_size,
+                       slot.buf);
+                close_slot(&slot);
+        }
+        closedir(dir);
+        return 0;
+}
+
 /* 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 5f2178d..66cc41f 100644
--- a/cache.h
+++ b/cache.h
@@ -1,32 +1,35 @@
 /*
  * 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
 
 typedef void (*cache_fill_fn)(void *cbdata);
 
 
 /* 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);
 
 
+/* List info about all cache entries on stdout */
+extern int cache_ls(const char *path);
+
 /* Print a message to stdout */
 extern void cache_log(const char *format, ...);
 
 #endif /* CGIT_CACHE_H */
diff --git a/cmd.c b/cmd.c
index e0eacbe..07f4707 100644
--- a/cmd.c
+++ b/cmd.c
@@ -1,112 +1,123 @@
 /* cmd.c: the cgit command dispatcher
  *
  * Copyright (C) 2008 Lars Hjemli
  *
  * Licensed under GNU General Public License v2
  *   (see COPYING for full license text)
  */
 
 #include "cgit.h"
 #include "cmd.h"
+#include "cache.h"
+#include "ui-shared.h"
 #include "ui-blob.h"
 #include "ui-commit.h"
 #include "ui-diff.h"
 #include "ui-log.h"
 #include "ui-patch.h"
 #include "ui-refs.h"
 #include "ui-repolist.h"
 #include "ui-snapshot.h"
 #include "ui-summary.h"
 #include "ui-tag.h"
 #include "ui-tree.h"
 
 static void blob_fn(struct cgit_context *ctx)
 {
         cgit_print_blob(ctx->qry.sha1, ctx->qry.path);
 }
 
 static void commit_fn(struct cgit_context *ctx)
 {
         cgit_print_commit(ctx->qry.sha1);
 }
 
 static void diff_fn(struct cgit_context *ctx)
 {
         cgit_print_diff(ctx->qry.sha1, ctx->qry.sha2, ctx->qry.path);
 }
 
-static void repolist_fn(struct cgit_context *ctx)
-{
-        cgit_print_repolist();
-}
-
 static void log_fn(struct cgit_context *ctx)
 {
         cgit_print_log(ctx->qry.sha1, ctx->qry.ofs, ctx->cfg.max_commit_count,
                        ctx->qry.grep, ctx->qry.search, ctx->qry.path, 1);
 }
 
+static void ls_cache_fn(struct cgit_context *ctx)
+{
+        ctx->page.mimetype = "text/plain";
+        ctx->page.filename = "ls-cache.txt";
+        cgit_print_http_headers(ctx);
+        cache_ls(ctx->cfg.cache_root);
+}
+
+static void repolist_fn(struct cgit_context *ctx)
+{
+        cgit_print_repolist();
+}
+
 static void patch_fn(struct cgit_context *ctx)
 {
         cgit_print_patch(ctx->qry.sha1);
 }
 
 static void refs_fn(struct cgit_context *ctx)
 {
         cgit_print_refs();
 }
 
 static void snapshot_fn(struct cgit_context *ctx)
 {
         cgit_print_snapshot(ctx->qry.head, ctx->qry.sha1,
                             cgit_repobasename(ctx->repo->url), ctx->qry.path,
                             ctx->repo->snapshots);
 }
 
 static void summary_fn(struct cgit_context *ctx)
 {
         cgit_print_summary();
 }
 
 static void tag_fn(struct cgit_context *ctx)
 {
         cgit_print_tag(ctx->qry.sha1);
 }
 
 static void tree_fn(struct cgit_context *ctx)
 {
         cgit_print_tree(ctx->qry.sha1, ctx->qry.path);
 }
 
 #define def_cmd(name, want_repo, want_layout) \
         {#name, name##_fn, want_repo, want_layout}
 
 struct cgit_cmd *cgit_get_cmd(struct cgit_context *ctx)
 {
         static struct cgit_cmd cmds[] = {
                 def_cmd(blob, 1, 0),
                 def_cmd(commit, 1, 1),
                 def_cmd(diff, 1, 1),
                 def_cmd(log, 1, 1),
+                def_cmd(ls_cache, 0, 0),
                 def_cmd(patch, 1, 0),
                 def_cmd(refs, 1, 1),
                 def_cmd(repolist, 0, 0),
                 def_cmd(snapshot, 1, 0),
                 def_cmd(summary, 1, 1),
                 def_cmd(tag, 1, 1),
                 def_cmd(tree, 1, 1),
         };
         int i;
 
         if (ctx->qry.page == NULL) {
                 if (ctx->repo)
                         ctx->qry.page = "summary";
                 else
                         ctx->qry.page = "repolist";
         }
 
         for(i = 0; i < sizeof(cmds)/sizeof(*cmds); i++)
                 if (!strcmp(ctx->qry.page, cmds[i].name))
                         return &cmds[i];
         return NULL;
 }