GSoC/Buflib: Enable compaction in buflib.

This enables the ability to allocate (and free) memory dynamically
without fragmentation, through compaction. This means allocations can move
and fragmentation be reduced. Most changes are preparing Rockbox for this,
which many times means adding a move callback which can temporarily disable
movement when the corresponding code is in a critical section.

For now, the audio buffer allocation has a central role, because it's the one
having allocated most. This buffer is able to shrink itself, for which it
needs to stop playback for a very short moment. For this,
audio_buffer_available() returns the size of the audio buffer which can
possibly be used by other allocations because the audio buffer can shrink.

lastfm scrobbling and timestretch can now be toggled at runtime without
requiring a reboot.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30381 a1c6a512-1295-4272-9138-f99709370657

apps/filetree.c

@@ -29,6 +29,7 @@
 #include <limits.h>
 #include "bookmark.h"
 #include "tree.h"
+#include "core_alloc.h"
 #include "settings.h"
 #include "filetypes.h"
 #include "talk.h"
@@ -60,7 +61,8 @@ int ft_build_playlist(struct tree_context* c, int start_index)
     int i;
     int start=start_index;
 
-    struct entry *entries = c->cache.entries;
+    tree_lock_cache(c);
+    struct entry *entries = tree_get_entries(c);
 
     for(i = 0;i < c->filesindir;i++)
     {
@@ -77,6 +79,8 @@ int ft_build_playlist(struct tree_context* c, int start_index)
         }
     }
 
+    tree_unlock_cache(c);
+
     return start_index;
 }
 
@@ -127,13 +131,15 @@ static void check_file_thumbnails(struct tree_context* c)
 {
     int i;
     struct dirent *entry;
-    struct entry* entries = c->cache.entries;
+    struct entry* entries;
     DIR *dir;
 
     dir = opendir(c->currdir);
     if(!dir)
         return;
     /* mark all files as non talking, except the .talk ones */
+    entries = tree_get_entries(c);
+    tree_lock_cache(c);
     for (i=0; i < c->filesindir; i++)
     {
         if (entries[i].attr & ATTR_DIRECTORY)
@@ -177,6 +183,7 @@ static void check_file_thumbnails(struct tree_context* c)
             }
         }
     }
+    tree_unlock_cache(c);
     closedir(dir);
 }
 
@@ -287,11 +294,11 @@ int ft_load(struct tree_context* c, const char* tempdir)
     c->dirsindir = 0;
     c->dirfull = false;
 
+    tree_lock_cache(c);
     while ((entry = readdir(dir))) {
         int len;
         struct dirinfo info;
-        struct entry* table = c->cache.entries;
-        struct entry* dptr = &table[files_in_dir];
+        struct entry* dptr = tree_get_entry_at(c, files_in_dir);
         if (!entry)
             break;
 
@@ -369,7 +376,7 @@ int ft_load(struct tree_context* c, const char* tempdir)
 
         ++files_in_dir;
 
-        dptr->name = &c->cache.name_buffer[name_buffer_used];
+        dptr->name = core_get_data(c->cache.name_buffer_handle)+name_buffer_used;
         dptr->time_write =
             (long)info.wrtdate<<16 |
             (long)info.wrttime; /* in one # */
@@ -384,13 +391,14 @@ int ft_load(struct tree_context* c, const char* tempdir)
     closedir(dir);
 
     compare_sort_dir = c->sort_dir;
-    qsort(c->cache.entries, files_in_dir, sizeof(struct entry), compare);
+    qsort(tree_get_entries(c), files_in_dir, sizeof(struct entry), compare);
 
     /* If thumbnail talking is enabled, make an extra run to mark files with
        associated thumbnails, so we don't do unsuccessful spinups later. */
     if (global_settings.talk_file_clip)
         check_file_thumbnails(c); /* map .talk to ours */
 
+    tree_unlock_cache(c);
     return 0;
 }
 #ifdef HAVE_LCD_BITMAP
@@ -424,15 +432,15 @@ int ft_enter(struct tree_context* c)
 {
     int rc = GO_TO_PREVIOUS;
     char buf[MAX_PATH];
-    struct entry* table = c->cache.entries;
-    struct entry *file = &table[c->selected_item];
+    struct entry* file = tree_get_entry_at(c, c->selected_item);
+    int file_attr = file->attr;
 
     if (c->currdir[1])
         snprintf(buf,sizeof(buf),"%s/%s",c->currdir, file->name);
     else
         snprintf(buf,sizeof(buf),"/%s",file->name);
 
-    if (file->attr & ATTR_DIRECTORY) {
+    if (file_attr & ATTR_DIRECTORY) {
         memcpy(c->currdir, buf, sizeof(c->currdir));
         if ( c->dirlevel < MAX_DIR_LEVELS )
             c->selected_item_history[c->dirlevel] = c->selected_item;
@@ -444,7 +452,7 @@ int ft_enter(struct tree_context* c)
         bool play = false;
         int start_index=0;
 
-        switch ( file->attr & FILE_ATTR_MASK ) {
+        switch ( file_attr & FILE_ATTR_MASK ) {
             case FILE_ATTR_M3U:
                 if (!bookmark_autoload(buf))
                     playlist_viewer_ex(buf);
@@ -612,7 +620,7 @@ int ft_enter(struct tree_context* c)
                 char *plugin = buf, *argument = NULL, lua_path[MAX_PATH];
                 int ret;
 
-                if ((file->attr & FILE_ATTR_MASK) == FILE_ATTR_LUA) {
+                if ((file_attr & FILE_ATTR_MASK) == FILE_ATTR_LUA) {
                     snprintf(lua_path, sizeof(lua_path)-1, "%s/lua.rock", VIEWERS_DIR); /* Use a #define here ? */
                     plugin = lua_path;
                     argument = buf;
@@ -658,6 +666,7 @@ int ft_enter(struct tree_context* c)
                     break;
                 }
 
+                struct entry* file = tree_get_entry_at(c, c->selected_item);
                 plugin = filetype_get_plugin(file);
                 if (plugin)
                 {