Fix deadlocks when trying to buffer large album art.

Internally, buffering tries to load the entire album art file into the
audio buffer, which will fail if the file is larger than the buffer.
Playback.c interprets a file failing to buffer to mean that the buffer
is full, so it waits for more space and tries again.  This results in a
deadlock since the file will never fit.

Change bufopen to return a new error condition when an image file will
not fit on the buffer because it is too large:  ERR_BITMAP_TOO_LARGE.
Note that we arbitrarily set "too large" to be within 64KB of the
entire buffer size or larger, this could be adjusted if needed.

Change audio_load_albumart to pass through error messages from bufopen.

In playback.c, check to see why audio_load_albumart fails.  If it fails
because the file is too large to buffer, simply ignore the file.  If it
fails because the file would fit but the buffer is full, try again
later.

Change-Id: I66799ae26f124b495e1522fce7285332f4cf986f

apps/buffering.c

@@ -999,7 +999,14 @@ int bufopen(const char *file, off_t offset, enum data_type type,
         DEBUGF("%s(): failed to add handle\n", __func__);
         mutex_unlock(&llist_mutex);
         close(fd);
+
+        /*warn playback.c if it is trying to buffer too large of an image*/
+        if(type == TYPE_BITMAP && padded_size >= buffer_len - 64*1024)
+        {
+            return ERR_BITMAP_TOO_LARGE;
+        }
         return ERR_BUFFER_FULL;
+
     }
 
     handle_id = h->id;

apps/buffering.h

@@ -47,6 +47,7 @@ enum data_type {
 #define ERR_HANDLE_NOT_DONE     -5
 #define ERR_UNSUPPORTED_TYPE    -6
 #define ERR_WRONG_THREAD        -7
+#define ERR_BITMAP_TOO_LARGE    -8
 
 /* Initialise the buffering subsystem */
 void buffering_init(void) INIT_ATTR;

apps/playback.c

@@ -1689,7 +1689,7 @@ static bool audio_load_cuesheet(struct track_info *infop,
 
 #ifdef HAVE_ALBUMART
 /* Load any album art for the file - returns false if the buffer is full */
-static bool audio_load_albumart(struct track_info *infop,
+static int audio_load_albumart(struct track_info *infop,
                                 struct mp3entry *track_id3)
 {
     FOREACH_ALBUMART(i)
@@ -1730,7 +1730,11 @@ static bool audio_load_albumart(struct track_info *infop,
         if (hid == ERR_BUFFER_FULL)
         {
             logf("buffer is full for now (%s)", __func__);
-            return false;
+            return ERR_BUFFER_FULL;
+        }
+        else if (hid == ERR_BITMAP_TOO_LARGE){
+            logf("image is too large to fit in buffer (%s)", __func__);
+            return ERR_BITMAP_TOO_LARGE;
         }
         else
         {
@@ -1981,7 +1985,12 @@ static int audio_finish_load_track(struct track_info *infop)
 
 #ifdef HAVE_ALBUMART
     /* Try to load album art for the track */
-    if (!audio_load_albumart(infop, track_id3))
+    int retval = audio_load_albumart(infop, track_id3);
+    if (retval == ERR_BITMAP_TOO_LARGE)
+    {
+        /* No space for album art on buffer because the file is larger than the buffer.
+        Ignore the file and keep buffering */
+    } else if (retval == ERR_BUFFER_FULL)
     {
         /* No space for album art on buffer, not an error */
         filling = STATE_FULL;

apps/radio/radioart.c

@@ -88,7 +88,7 @@ static int load_radioart_image(struct radioart *ra, const char* preset_name,
     user_data.embedded_albumart = NULL;
     user_data.dim = &ra->dim;
     ra->handle = bufopen(path, 0, TYPE_BITMAP, &user_data);
-    if (ra->handle == ERR_BUFFER_FULL)
+    if (ra->handle == ERR_BUFFER_FULL || ra->handle == ERR_BITMAP_TOO_LARGE)
     {
         int i = find_oldest_image_index();
         if (i != -1)