tracklist: use lower number unique track IDs

This is easier for users to read and type; and _might_ help with
race conditions due to fast object recycling from GC.  We'll also be
implementing playist versioning on top of this in the next commits
for MPD protocol compatibility.

Unfortunately this adds an additional 40 bytes of per-track overhead
(on 64-bit systems, its only 20 bytes on 32-bit).  However, we may
be able to save memory in the future by supporting dtas-mlib node
IDs if we integrate dtas-player with DTAS::Mlib.

While we're at it, include a minor speedup for
DTAS::Tracklist#remove_track by using Array#delete_at instead of
relying on Array#compact!  after assignment

This should improve "dtas-tl cat" output readability dramatically.

The state file (~/.dtas/player_state.yml) remains compatible
between dtas-player before and after this change.

1 files changed, 26 insertions, 11 deletions

diff --git a/lib/dtas/tracklist.rb b/lib/dtas/tracklist.rb
index 63fe4ec..696026a 100644
--- a/lib/dtas/tracklist.rb
+++ b/lib/dtas/tracklist.rb
@@ -2,6 +2,7 @@
 # License: GPLv3 or later (https://www.gnu.org/licenses/gpl-3.0.txt)
 require_relative '../dtas'
 require_relative 'serialize'
+require_relative 'track'
 
 # the a tracklist object for -player
 # this is inspired by the MPRIS 2.0 TrackList spec
@@ -19,7 +20,7 @@ class DTAS::Tracklist # :nodoc:
   def self.load(hash)
     obj = new
     obj.instance_eval do
-      list = hash["list"] and @list.replace(list)
+      list = hash["list"] and @list.replace(list.map! { |s| new_track(s) })
       @pos = hash["pos"] || -1
       @repeat = hash["repeat"] || false
     end
@@ -27,13 +28,27 @@ class DTAS::Tracklist # :nodoc:
   end
 
   def to_hsh
-    ivars_to_hash(SIVS).delete_if { |k,v| TL_DEFAULTS[k] == v }
+    h = ivars_to_hash(SIVS)
+    h.delete_if { |k,v| TL_DEFAULTS[k] == v }
+    list = h['list'] and list.map!(&:to_path)
+    h
   end
 
   def initialize
     TL_DEFAULTS.each { |k,v| instance_variable_set("@#{k}", v) }
     @list = []
     @goto_off = @goto_pos = nil
+    @track_nr = 0
+  end
+
+  def new_track(path)
+    n = @track_nr += 1
+
+    # nobody needs a billion tracks in their tracklist, right?
+    # avoid promoting to Bignum on 32-bit
+    @track_nr = n = 1 if n >= 0x3fffffff
+
+    DTAS::Track.new(n, path)
   end
 
   def reset
@@ -49,7 +64,7 @@ class DTAS::Tracklist # :nodoc:
   # a few tens of tracks, maybe a hundred at most.
   def _track_id_map
     by_track_id = {}
-    @list.each_with_index { |t,i| by_track_id[t.object_id] = i }
+    @list.each_with_index { |t,i| by_track_id[t.track_id] = i }
     by_track_id
   end
 
@@ -58,12 +73,12 @@ class DTAS::Tracklist # :nodoc:
     track_ids.map do |track_id|
       idx = by_track_id[track_id]
       # dtas-mpris fills in the metadata, we just return a path
-      [ track_id, idx ? @list[idx] : nil ]
+      [ track_id, idx ? @list[idx].to_path : nil ]
     end
   end
 
   def tracks
-    @list.map(&:object_id)
+    @list.map(&:track_id)
   end
 
   def advance_track(repeat_ok = true)
@@ -80,7 +95,7 @@ class DTAS::Tracklist # :nodoc:
     else
       return
     end
-    [ @list[next_pos], next_off ]
+    [ @list[next_pos].to_path, next_off ]
   end
 
   def cur_track
@@ -88,6 +103,7 @@ class DTAS::Tracklist # :nodoc:
   end
 
   def add_track(track, after_track_id = nil, set_as_current = false)
+    track = new_track(track)
     if after_track_id
       by_track_id = _track_id_map
       idx = by_track_id[after_track_id] or
@@ -106,27 +122,26 @@ class DTAS::Tracklist # :nodoc:
         @pos += 1 if @pos >= 0
       end
     end
-    track.object_id
+    track.track_id
   end
 
   def remove_track(track_id)
     by_track_id = _track_id_map
     idx = by_track_id.delete(track_id) or return false
-    @list[idx] = nil
-    @list.compact!
+    track = @list.delete_at(idx)
     len = @list.size
     if @pos >= len
       @pos = len == 0 ? TL_DEFAULTS["pos"] : len
     end
     @goto_pos = @goto_pos = nil # TODO: reposition?
-    true
+    track.to_path
   end
 
   def go_to(track_id, offset_hhmmss = nil)
     by_track_id = _track_id_map
     if idx = by_track_id[track_id]
       @goto_off = offset_hhmmss
-      return @list[@goto_pos = idx]
+      return @list[@goto_pos = idx].to_path
     end
     @goto_pos = nil
     # noop if track_id is invalid