86 lines
2.5 KiB
Erlang
86 lines
2.5 KiB
Erlang
%%%%----------------------------------------------------
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%%% @author Mattias Pettersson <mattiaspgames@gmail.com>
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%%% @copyright 2011 Mattias Pettersson
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%%% @doc Database for runtime game variable storage.
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%%% @end
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-module(ggs_db).
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-import(mnesia).
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%-compile({no_auto_import,[length/2]}).
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-export([init/0,setItem/4,getItem/3,removeItem/3,key/3,clear/2,length/2]).
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-include("ggs_db.hrl").
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%%-----------------------------------------------------
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%% Creation
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%%-----------------------------------------------------
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init() ->
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mnesia:create_table(data, [{attributes, record_info(fields, data)}]).
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%%-----------------------------------------------------
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%% Test
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%%-----------------------------------------------------
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%test_data() ->
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% set(0, "Hello"),
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% get(0).
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%%-----------------------------------------------------
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%% Insertions
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%%-----------------------------------------------------
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setItem(Db,Ns,Key,Value) ->
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Fun = fun() ->
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Data = #data{key = {Db,Ns,Key}, value = Value},
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mnesia:write(Data)
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end,
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mnesia:transaction(Fun).
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%%-----------------------------------------------------
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%% Deletions
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%%-----------------------------------------------------
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removeItem(Db,Ns,Key) ->
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Fun = fun() ->
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mnesia:delete({data,{Db,Ns,Key}})
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end,
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mnesia:transaction(Fun).
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clear(Db,Ns) ->
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Fun = fun() ->
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Keys = mnesia:all_keys(data),
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Rest = lists:filter(fun({A,B,_}) -> ((A==Db) and (B==Ns)) end, Keys),
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lists:map(fun({A,B,C}) -> removeItem(A,B,C) end, Rest)
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end,
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{atomic, Ret} = mnesia:transaction(Fun),
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Ret.
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%%-----------------------------------------------------
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%% Querries
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%%-----------------------------------------------------
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getItem(Db,Ns,Key) ->
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Fun = fun() ->
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[Data] = mnesia:read(data, {Db,Ns,Key}),
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Data#data.value
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end,
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mnesia:transaction(Fun).
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length(Db,Ns) ->
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Fun = fun() ->
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Keys = mnesia:all_keys(data),
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length(lists:filter(fun({A,B,_}) -> ((A==Db) and (B==Ns)) end, Keys))
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end,
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{atomic, Ret} = mnesia:transaction(Fun),
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Ret.
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key(Db,Ns,Position) ->
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Fun = fun() ->
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Keys = mnesia:all_keys(data),
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Rest = lists:filter(fun({A,B,_}) -> ((A==Db) and (B==Ns)) end, Keys),
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lists:nth(Position, Rest)
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end,
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{atomic, Ret} = mnesia:transaction(Fun),
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Ret.
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