Optimize file_cache_get() by only moving element to front if needed

(most of the time there is no need).
Reduce code redundancy in file_cache_put() by calling file_cache_get().
Enhance debugging code.

diff --git a/src/filecache.c b/src/filecache.c
index 2d9374d..b30e270 100644 (file)
--- a/src/filecache.c
+++ b/src/filecache.c
@@ -13,6 +13,9 @@
 #include "main.h"
 #include "filecache.h"
 
+/* Set to TRUE to add file cache dumps to the debug output */
+const gboolean debug_file_cache = FALSE;
+
 /* this implements a simple LRU algorithm */
 
 struct _FileCacheData {
@@ -28,15 +31,6 @@ struct _FileCacheEntry {
        gulong size;
        };
 
-static gint file_cache_entry_compare_cb(gconstpointer a, gconstpointer b)
-{
-       const FileCacheEntry *fca = a;
-       const FileData *fd = b;
-       if (fca->fd == fd) return 0;
-       return 1;
-}
-
-
 FileCacheData *file_cache_new(FileCacheReleaseFunc release, gulong max_size)
 {
        FileCacheData *fc = g_new(FileCacheData, 1);
@@ -47,19 +41,31 @@ FileCacheData *file_cache_new(FileCacheReleaseFunc release, gulong max_size)
        return fc;
 }
 
-gint file_cache_get(FileCacheData *fc, FileData *fd)
+gboolean file_cache_get(FileCacheData *fc, FileData *fd)
 {
        GList *work;
        
-       work = g_list_find_custom(fc->list, fd, file_cache_entry_compare_cb);
-       if (work)
+       g_assert(fc && fd);
+
+       work = fc->list;
+       while (work)
                {
-               fc->list = g_list_remove_link(fc->list, work);
-               fc->list = g_list_concat(work, fc->list);
-               DEBUG_1("cache hit: %s", fd->path);
-               return TRUE;
+               FileCacheEntry *fce = work->data;
+               if (fce->fd == fd)
+                       {
+                       /* entry exists */
+                       DEBUG_1("cache hit: fc=%p %s", fc, fd->path);
+                       if (work == fc->list) return TRUE; /* already at the beginning */
+                       /* move it to the beginning */
+                       DEBUG_1("cache move to front: fc=%p %s", fc, fd->path);
+                       fc->list = g_list_remove_link(fc->list, work);
+                       fc->list = g_list_concat(work, fc->list);
+                       if (debug_file_cache) file_cache_dump(fc);
+                       return TRUE;
+                       }
+               work = work->next;
                }
-       DEBUG_1("cache miss: %s", fd->path);
+       DEBUG_1("cache miss: fc=%p %s", fc, fd->path);
        return FALSE;
 }
 
@@ -67,6 +73,9 @@ void file_cache_set_size(FileCacheData *fc, gulong size)
 {
        GList *work;
        FileCacheEntry *last_fe;
+
+       if (debug_file_cache) file_cache_dump(fc);
+
        work = g_list_last(fc->list);
        while (fc->size > size && work)
                {
@@ -76,7 +85,7 @@ void file_cache_set_size(FileCacheData *fc, gulong size)
                fc->list = g_list_delete_link(fc->list, work);
                work = prev;
                
-               DEBUG_1("cache remove: %s", last_fe->fd->path);
+               DEBUG_1("cache remove: fc=%p %s", fc, last_fe->fd->path);
                fc->size -= last_fe->size;
                fc->release(last_fe->fd);
                file_data_unref(last_fe->fd);
@@ -86,19 +95,11 @@ void file_cache_set_size(FileCacheData *fc, gulong size)
 
 void file_cache_put(FileCacheData *fc, FileData *fd, gulong size)
 {
-       GList *work;
        FileCacheEntry *fe;
 
-       work = g_list_find_custom(fc->list, fd, file_cache_entry_compare_cb);
-       if (work)
-               { 
-               /* entry already exists, move it to the beginning */
-               fc->list = g_list_remove_link(fc->list, work);
-               fc->list = g_list_concat(work, fc->list);
-               return;
-               }
+       if (file_cache_get(fc, fd)) return;
        
-       DEBUG_1("cache add: %s", fd->path);
+       DEBUG_1("cache add: fc=%p %s", fc, fd->path);
        fe = g_new(FileCacheEntry, 1);
        fe->fd = file_data_ref(fd);
        fe->size = size;
@@ -128,13 +129,13 @@ void file_cache_dump(FileCacheData *fc)
 {
        GList *work;
        work = fc->list;
-       
-       DEBUG_1("cache dump: max size:%ld size:%ld", fc->max_size, fc->size);
+       guint n = 0;
+       DEBUG_1("cache dump: fc=%p max size:%ld size:%ld", fc, fc->max_size, fc->size);
                
        while (work)
                {
                FileCacheEntry *fe = work->data;
                work = work->next;
-               DEBUG_1("cache entry: %s %ld", fe->fd->path, fe->size);
+               DEBUG_1("cache entry: fc=%p [%lu] %s %ld", fc, ++n, fe->fd->path, fe->size);
                }
 }

diff --git a/src/filecache.h b/src/filecache.h
index 84a2533..8dbe68b 100644 (file)
--- a/src/filecache.h
+++ b/src/filecache.h
@@ -20,7 +20,7 @@ typedef void (*FileCacheReleaseFunc)(FileData *fd);
 
 
 FileCacheData *file_cache_new(FileCacheReleaseFunc release, gulong max_size);
-gint file_cache_get(FileCacheData *fc, FileData *fd);
+gboolean file_cache_get(FileCacheData *fc, FileData *fd);
 void file_cache_put(FileCacheData *fc, FileData *fd, gulong size);
 void file_cache_dump(FileCacheData *fc);
 void file_cache_set_size(FileCacheData *fc, gulong size);