src/task_registry.erl

   1 %%%-------------------------------------------------------------------
   2 %%% File    : task_registry.erl
   3 %%% Author  :  <>
   4 %%% Description :
   5 %%%
   6 %%% Created : 25 Mar 2011 by  <>
   7 %%%-------------------------------------------------------------------
   8 -module(makerl.task_registry).
   9 -include("makerl.hrl").
  10
  11 -import(gen_server).
  12 -import(ets).
  13
  14 -behaviour(gen_server).
  15
  16 %% API
  17 -export([start_link/0,
  18          add/1,
  19          set_pid/2,
  20          find_by_target/1,
  21          find_pid_by_target/1]).
  22
  23 %% gen_server callbacks
  24 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
  25          terminate/2, code_change/3]).
  26
  27 -define(TIMEOUT, infinity).
  28 -record(state, {}).
  29
  30 %%====================================================================
  31 %% API
  32 %%====================================================================
  33 %%--------------------------------------------------------------------
  34 %% Function: start_link() -> {ok,Pid} | ignore | {error,Error}
  35 %% Description: Starts the server
  36 %%--------------------------------------------------------------------
  37 start_link() ->
  38     gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
  39
  40 -spec add(#task{}) -> true.
  41 add(Task) ->
  42     gen_server:call(?MODULE, {register, Task}, ?TIMEOUT).
  43
  44 -spec set_pid(string(), pid()) -> {ok, pid()} | {error, any()}.
  45 set_pid(Target, Pid) ->
  46     gen_server:call(?MODULE, {set_pid, Target, Pid}, ?TIMEOUT).
  47
  48 -spec find_pid_by_target(string()) -> {ok, pid()} | {error, any()}.
  49 find_pid_by_target(Target) ->
  50     gen_server:call(?MODULE, {find_pid_by_target, Target}, ?TIMEOUT).
  51
  52 -spec find_by_target(string()) -> {ok, #task{} } | {error, any()}.
  53 find_by_target(Target) ->
  54     gen_server:call(?MODULE, {find_by_target, Target}, ?TIMEOUT).
  55
  56 %%====================================================================
  57 %% gen_server callbacks
  58 %%====================================================================
  59
  60 %%--------------------------------------------------------------------
  61 %% Function: init(Args) -> {ok, State} |
  62 %%                         {ok, State, Timeout} |
  63 %%                         ignore               |
  64 %%                         {stop, Reason}
  65 %% Description: Initiates the server
  66 %%--------------------------------------------------------------------
  67 init([]) ->
  68     case ets:info(?MODULE) of
  69         undefined -> ets:new(?MODULE, [public, named_table]);
  70         _ -> ets:delete_all_objects(?MODULE)
  71     end,
  72     {ok, #state{}}.
  73
  74
  75
  76 %%--------------------------------------------------------------------
  77 %% Function: %% handle_call(Request, From, State) -> {reply, Reply, State} |
  78 %%                                      {reply, Reply, State, Timeout} |
  79 %%                                      {noreply, State} |
  80 %%                                      {noreply, State, Timeout} |
  81 %%                                      {stop, Reason, Reply, State} |
  82 %%                                      {stop, Reason, State}
  83 %% Description: Handling call messages
  84 %%--------------------------------------------------------------------
  85 handle_call({find_pid_by_target, Target}, _From, State) ->
  86     Reply = case private_find_by_target(Target) of
  87                 {ok, Task} -> {ok, Task#task.pid};
  88                 X -> X
  89             end,
  90     {reply, Reply, State};
  91 handle_call({find_by_target, Target}, _From, State) ->
  92     {reply, private_find_by_target(Target), State};
  93 handle_call({set_pid, Target, Pid}, _From, State) ->
  94     Reply = case private_find_by_target(Target) of
  95                 {ok, Task} ->
  96                     Res = ets:insert(?MODULE, {Target, Task#task{ pid = Pid }}),
  97                     case Res of
  98                         true -> {ok, self()};
  99                         _ -> {error, ?MODULE, set_pid, [Target, Pid]}
 100                     end;
 101                 X -> X
 102             end,
 103     {reply, Reply, State};
 104 handle_call({register, Task}, _From, State) ->
 105     Reply = ets:insert(?MODULE, {Task#task.target, Task}),
 106     {reply, Reply, State}.
 107
 108 %%--------------------------------------------------------------------
 109 %% Function: handle_cast(Msg, State) -> {noreply, State} |
 110 %%                                      {noreply, State, Timeout} |
 111 %%                                      {stop, Reason, State}
 112 %% Description: Handling cast messages
 113 %%--------------------------------------------------------------------
 114 handle_cast(_Msg, State) ->
 115     {noreply, State}.
 116
 117 %%--------------------------------------------------------------------
 118 %% Function: handle_info(Info, State) -> {noreply, State} |
 119 %%                                       {noreply, State, Timeout} |
 120 %%                                       {stop, Reason, State}
 121 %% Description: Handling all non call/cast messages
 122 %%--------------------------------------------------------------------
 123 handle_info(_Info, State) ->
 124     {noreply, State}.
 125
 126 %%--------------------------------------------------------------------
 127 %% Function: terminate(Reason, State) -> void()
 128 %% Description: This function is called by a gen_server when it is about to
 129 %% terminate. It should be the opposite of Module:init/1 and do any necessary
 130 %% cleaning up. When it returns, the gen_server terminates with Reason.
 131 %% The return value is ignored.
 132 %%--------------------------------------------------------------------
 133 terminate(_Reason, _State) ->
 134     ok.
 135
 136 %%--------------------------------------------------------------------
 137 %% Func: code_change(OldVsn, State, Extra) -> {ok, NewState}
 138 %% Description: Convert process state when code is changed
 139 %%--------------------------------------------------------------------
 140 code_change(_OldVsn, State, _Extra) ->
 141     {ok, State}.
 142
 143 %%--------------------------------------------------------------------
 144 %%% Internal functions
 145 %%--------------------------------------------------------------------
 146 private_find_by_target(Target) ->
 147     case ets:lookup(?MODULE, Target) of
 148         [{Target, Task}|_] -> {ok, Task};
 149         X -> {error, X}
 150     end.
 151