lib/etorrent-1.0/src/etorrent_tracking_map.erl

   1 %%%-------------------------------------------------------------------
   2 %%% File    : etorrent_tracking_map.erl
   3 %%% Author  : Jesper Louis Andersen <>
   4 %%% Description : Tracking Map manipulations
   5 %%%
   6 %%% Created : 15 Jun 2008 by Jesper Louis Andersen <>
   7 %%%-------------------------------------------------------------------
   8 -module(etorrent_tracking_map).
   9
  10 -include_lib("stdlib/include/qlc.hrl").
  11 -include("etorrent_mnesia_table.hrl").
  12
  13 %% API
  14 -export([all/0, new/3, delete/1, select/1, statechange/2,
  15          is_ready_for_checking/1]).
  16
  17 %%====================================================================
  18 %% API
  19 %%====================================================================
  20 %%--------------------------------------------------------------------
  21 %% Function: new(Filename, Supervisor) -> ok
  22 %% Description: Add a new torrent given by File with the Supervisor
  23 %%   pid as given to the database structure.
  24 %%--------------------------------------------------------------------
  25 new(File, Supervisor, Id) when is_integer(Id), is_pid(Supervisor), is_list(File) ->
  26     mnesia:dirty_write(#tracking_map { id = Id,
  27                                        filename = File,
  28                                        supervisor_pid = Supervisor,
  29                                        info_hash = unknown,
  30                                        state = awaiting}).
  31
  32 %%--------------------------------------------------------------------
  33 %% Function: all/0
  34 %% Description: Return everything we are currently tracking
  35 %%--------------------------------------------------------------------
  36 all() ->
  37     mnesia:transaction(
  38       fun () ->
  39               qlc:e(qlc:q([T || T <- mnesia:table(tracking_map)]))
  40       end).
  41
  42 %%--------------------------------------------------------------------
  43 %% Function: select(Id) -> [#tracking_map]
  44 %% Args:    Id ::= integer() | {filename, FN} | {infohash, IH}
  45 %%
  46 %%          FN ::= string()
  47 %%          IH ::= binary()
  48 %% Description: Find tracking map matching the filename in question.
  49 %%--------------------------------------------------------------------
  50 select(Id) when is_integer(Id) ->
  51     mnesia:transaction(
  52       fun () ->
  53               mnesia:read(tracking_map, Id, read)
  54       end);
  55 select({filename,Filename}) ->
  56     mnesia:transaction(
  57       fun () ->
  58               Query = qlc:q([T || T <- mnesia:table(tracking_map),
  59                                   T#tracking_map.filename == Filename]),
  60               qlc:e(Query)
  61       end);
  62 select({infohash, InfoHash}) ->
  63     mnesia:transaction(
  64       fun () ->
  65               Q = qlc:q([T || T <- mnesia:table(tracking_map),
  66                               T#tracking_map.info_hash =:= InfoHash]),
  67               qlc:e(Q)
  68       end).
  69
  70 %%--------------------------------------------------------------------
  71 %% Function: delete(Id) -> ok
  72 %% Description: Clean out all references to torrents matching Pid
  73 %%--------------------------------------------------------------------
  74 delete(Id) when is_integer(Id) ->
  75     mnesia:dirty_delete(tracking_map, Id).
  76
  77 %%--------------------------------------------------------------------
  78 %% Function: statechange(Id, What) -> ok
  79 %% Description: Alter the state of the Tracking map identified by Id
  80 %%   by What (see alter_map/2).
  81 %%--------------------------------------------------------------------
  82 statechange(Id, What) ->
  83     F = fun () ->
  84                 [TM] = mnesia:read(tracking_map, Id, write),
  85                 mnesia:write(alter_map(TM, What))
  86         end,
  87     {atomic, _} = mnesia:transaction(F),
  88     ok.
  89
  90 %%--------------------------------------------------------------------
  91 %% Function: is_ready_for_checking(Id) -> bool()
  92 %% Description: Attempt to mark the torrent for checking. If this
  93 %%   succeeds, returns true, else false
  94 %%--------------------------------------------------------------------
  95 is_ready_for_checking(Id) ->
  96     F = fun () ->
  97                 Q = qlc:q([TM || TM <- mnesia:table(tracking_map),
  98                                  TM#tracking_map.state =:= checking]),
  99                 case length(qlc:e(Q)) of
 100                     0 ->
 101                         [TM] = mnesia:read(tracking_map, Id, write),
 102                         mnesia:write(TM#tracking_map { state = checking }),
 103                         true;
 104                     _ ->
 105                         false
 106                 end
 107         end,
 108     {atomic, T} = mnesia:transaction(F),
 109     T.
 110
 111 %%====================================================================
 112 %% Internal functions
 113 %%====================================================================
 114
 115 alter_map(TM, What) ->
 116     case What of
 117         {infohash, IH} ->
 118             TM#tracking_map { info_hash = IH };
 119         started ->
 120             TM#tracking_map { state = started };
 121         stopped ->
 122             TM#tracking_map { state = stopped }
 123     end.