playlist: Simplify playlist modified detection

Any modifications to the playlist (insert, delete, shuffle, etc)
will cause the modified flag to be set. The flag is cleared when
the playlist is saved. Code that generates playlists can manually
clear the modified flag if appropriate; there is now a proper API
for this so the tagcache and pictureflow don't need to resort to
hacks.

Change-Id: I8d3c723265a41db07a13de3f1d2abb0444528d57

7 files changed, 30 insertions, 47 deletions

diff --git a/apps/playlist.c b/apps/playlist.c
index f2b0bb197f..c755aca9fd 100644
--- a/apps/playlist.c
+++ b/apps/playlist.c
@@ -576,20 +576,18 @@ static void empty_playlist_unlocked(struct playlist_info* playlist, bool resume)
     playlist->utf8 = true;
     playlist->control_created = false;
     playlist->in_ram = false;
+    playlist->modified = false;
 
     playlist->fd = -1;
     playlist->control_fd = -1;
-    playlist->num_inserted_tracks = 0;
 
     playlist->index = 0;
     playlist->first_index = 0;
     playlist->amount = 0;
     playlist->last_insert_pos = -1;
 
-    playlist->deleted = false;
     playlist->started = false;
     playlist->pending_control_sync = false;
-    playlist->shuffle_modified = false;
 
     if (!resume && playlist == &current_playlist)
     {
@@ -810,9 +808,7 @@ static int recreate_control_unlocked(struct playlist_info* playlist)
     }
 
     playlist->seed = 0;
-    playlist->shuffle_modified = false;
-    playlist->deleted = false;
-    playlist->num_inserted_tracks = 0;
+    playlist->modified = true;
 
     for (i=0; i<playlist->amount; i++)
     {
@@ -841,8 +837,6 @@ static int recreate_control_unlocked(struct playlist_info* playlist)
 
             if (result < 0)
                 break;
-
-            playlist->num_inserted_tracks++;
         }
     }
 
@@ -1373,18 +1367,11 @@ static int remove_all_tracks_unlocked(struct playlist_info *playlist, bool write
 #endif
 
     /* Update playlist state as if by remove_track_unlocked() */
-    bool inserted = playlist->indices[0] & PLAYLIST_INSERT_TYPE_MASK;
-
     playlist->index = 0;
+    playlist->first_index = 0;
     playlist->amount = 1;
     playlist->indices[0] |= PLAYLIST_QUEUED;
-
-    if (inserted)
-        playlist->num_inserted_tracks = 1;
-    else
-        playlist->deleted = true;
-
-    playlist->first_index = 0;
+    playlist->modified = true;
 
     if (playlist->last_insert_pos == 0)
         playlist->last_insert_pos = -1;
@@ -1558,7 +1545,7 @@ static int add_track_to_playlist_unlocked(struct playlist_info* playlist,
     dc_init_filerefs(playlist, insert_position, 1);
 
     playlist->amount++;
-    playlist->num_inserted_tracks++;
+    playlist->modified = true;
 
     return insert_position;
 }
@@ -1614,13 +1601,10 @@ static int remove_track_unlocked(struct playlist_info* playlist,
 {
     int i;
     int result = 0;
-    bool inserted;
 
     if (playlist->amount <= 0)
         return -1;
 
-    inserted = playlist->indices[position] & PLAYLIST_INSERT_TYPE_MASK;
-
 #ifdef HAVE_DIRCACHE
     struct dircache_fileref *dcfrefs = NULL;
     if (playlist->dcfrefs_handle)
@@ -1638,11 +1622,7 @@ static int remove_track_unlocked(struct playlist_info* playlist,
     }
 
     playlist->amount--;
-
-    if (inserted)
-        playlist->num_inserted_tracks--;
-    else
-        playlist->deleted = true;
+    playlist->modified = true;
 
     /* update stored indices if needed */
     if (position < playlist->index)
@@ -1735,8 +1715,7 @@ static int randomise_playlist_unlocked(struct playlist_info* playlist,
     playlist->last_insert_pos = -1;
 
     playlist->seed = seed;
-    if (playlist->num_inserted_tracks > 0 || playlist->deleted)
-        playlist->shuffle_modified = true;
+    playlist->modified = true;
 
     if (write)
     {
@@ -1800,9 +1779,8 @@ static int sort_playlist_unlocked(struct playlist_info* playlist,
 
     /* indices have been moved so last insert position is no longer valid */
     playlist->last_insert_pos = -1;
+    playlist->modified = true;
 
-    if (!playlist->num_inserted_tracks && !playlist->deleted)
-        playlist->shuffle_modified = false;
     if (write && playlist->control_fd >= 0)
     {
         playlist->first_index = 0;
@@ -2905,20 +2883,25 @@ int playlist_insert_track(struct playlist_info* playlist, const char *filename,
     return result;
 }
 
-/* returns true if playlist has been modified */
+/* returns true if playlist has been modified by the user */
 bool playlist_modified(const struct playlist_info* playlist)
 {
     if (!playlist)
         playlist = &current_playlist;
 
-    if (playlist->shuffle_modified ||
-        playlist->deleted ||
-        playlist->num_inserted_tracks > 0)
-    {
-        return true;
-    }
+    return playlist->modified;
+}
+
+/*
+ * Set the playlist modified status. Useful for clearing the modified status
+ * after dynamically building a playlist.
+ */
+void playlist_set_modified(struct playlist_info *playlist, bool modified)
+{
+    if (!playlist)
+        playlist = &current_playlist;
 
-    return false;
+    playlist->modified = modified;
 }
 
 /*
@@ -3938,6 +3921,7 @@ int playlist_save(struct playlist_info* playlist, char *filename,
     if (fd >= 0)
         close(fd);
 
+    playlist->modified = false;
     cpu_boost(false);
 
     return result;
@@ -3996,9 +3980,7 @@ int playlist_set_current(struct playlist_info* playlist)
     current_playlist.amount = playlist->amount;
     current_playlist.last_insert_pos = playlist->last_insert_pos;
     current_playlist.seed = playlist->seed;
-    current_playlist.shuffle_modified = playlist->shuffle_modified;
-    current_playlist.deleted = playlist->deleted;
-    current_playlist.num_inserted_tracks = playlist->num_inserted_tracks;
+    current_playlist.modified = playlist->modified;
 
     memcpy(current_playlist.control_cache, playlist->control_cache,
         sizeof(current_playlist.control_cache));
diff --git a/apps/playlist.h b/apps/playlist.h
index d56a6fd659..cb79eea96c 100644
--- a/apps/playlist.h
+++ b/apps/playlist.h
@@ -75,11 +75,11 @@ struct playlist_info
     bool utf8;           /* playlist is in .m3u8 format             */
     bool control_created; /* has control file been created?         */
     bool in_ram;         /* playlist stored in ram (dirplay)        */
+    bool modified;       /* has playlist been modified by the user? */
     int  fd;             /* descriptor of the open playlist file    */
     int  control_fd;     /* descriptor of the open control file     */
     int  max_playlist_size; /* Max number of files in playlist. Mirror of
                               global_settings.max_files_in_playlist */
-    int  num_inserted_tracks; /* number of tracks inserted           */
     unsigned long *indices; /* array of indices            */
 
     struct chunk_alloc_header name_chunk_buffer; /* chunk buffer for 
@@ -89,11 +89,8 @@ struct playlist_info
     int  first_index;    /* index of first song in playlist         */
     int  amount;         /* number of tracks in the index           */
     int  last_insert_pos; /* last position we inserted a track      */
-    bool deleted;        /* have any tracks been deleted?           */
     bool started;       /* has playlist been started?               */
     bool pending_control_sync; /* control file needs to be synced   */
-    bool shuffle_modified; /* has playlist been shuffled with
-                              inserted tracks?                      */
     int last_shuffled_start; /* number of tracks when insert last
                                     shuffled command start */
     int  seed;           /* shuffle seed                            */
@@ -166,6 +163,7 @@ int playlist_randomise(struct playlist_info* playlist, unsigned int seed,
                        bool start_current);
 int playlist_sort(struct playlist_info* playlist, bool start_current);
 bool playlist_modified(const struct playlist_info* playlist);
+void playlist_set_modified(struct playlist_info* playlist, bool modified);
 int playlist_get_first_index(const struct playlist_info* playlist);
 int playlist_get_seed(const struct playlist_info* playlist);
 int playlist_amount_ex(const struct playlist_info* playlist);
diff --git a/apps/playlist_viewer.c b/apps/playlist_viewer.c
index 4328a6de1d..8761f0dbc9 100644
--- a/apps/playlist_viewer.c
+++ b/apps/playlist_viewer.c
@@ -975,6 +975,7 @@ enum playlist_viewer_result playlist_viewer_ex(const char* filename,
                     if (global_settings.playlist_shuffle)
                         start_index = playlist_shuffle(current_tick, start_index);
                     playlist_start(start_index, 0, 0);
+                    playlist_set_modified(NULL, false);
 
                     if (viewer.initial_selection)
                         *(viewer.initial_selection) = viewer.selected_track;
diff --git a/apps/plugin.c b/apps/plugin.c
index 1a0aedf3cc..3db4bb2d80 100644
--- a/apps/plugin.c
+++ b/apps/plugin.c
@@ -829,6 +829,7 @@ static const struct plugin_api rockbox_api = {
     tagtree_subentries_do_action,
 #endif
     adjust_volume,
+    playlist_set_modified,
 };
 
 static int plugin_buffer_handle;
diff --git a/apps/plugin.h b/apps/plugin.h
index cf6a1bc4e4..c54ef180ec 100644
--- a/apps/plugin.h
+++ b/apps/plugin.h
@@ -954,6 +954,7 @@ struct plugin_api {
     bool (*tagtree_subentries_do_action)(bool (*action_cb)(const char *file_name));
 #endif
     void (*adjust_volume)(int steps);
+    void (*playlist_set_modified)(struct playlist_info *playlist, bool modified);
 };
 
 /* plugin header */
diff --git a/apps/plugins/pictureflow/pictureflow.c b/apps/plugins/pictureflow/pictureflow.c
index 45c4e0fcda..67c26a7dc8 100644
--- a/apps/plugins/pictureflow/pictureflow.c
+++ b/apps/plugins/pictureflow/pictureflow.c
@@ -4246,7 +4246,7 @@ static bool start_playback(bool return_to_WPS)
             start_index = rb->playlist_shuffle(*rb->current_tick, pf_tracks.sel);
     }
     rb->playlist_start(start_index, 0, 0);
-    rb->playlist_get_current()->num_inserted_tracks = 0; /* prevent warn_on_pl_erase */
+    rb->playlist_set_modified(NULL, false);
     old_shuffle = shuffle;
 #ifdef USEGSLIB
     if (!return_to_WPS)
diff --git a/apps/tagtree.c b/apps/tagtree.c
index 72eec1494c..e715d4518b 100644
--- a/apps/tagtree.c
+++ b/apps/tagtree.c
@@ -2359,7 +2359,7 @@ static int tagtree_play_folder(struct tree_context* c)
     }
 
     playlist_start(start_index, 0, 0);
-    playlist_get_current()->num_inserted_tracks = 0; /* make warn on playlist erase work */
+    playlist_set_modified(NULL, false);
     return 0;
 }