| %% Copyright (c) 2013, Pedram Nimreezi <deadzen@deadzen.com> |
| %% |
| %% Permission to use, copy, modify, and/or distribute this software for any |
| %% purpose with or without fee is hereby granted, provided that the above |
| %% copyright notice and this permission notice appear in all copies. |
| %% |
| %% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| %% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| %% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
| %% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| %% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| %% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
| %% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| |
| -module(gr_counter). |
| |
| -behaviour(gen_server). |
| |
| %% API |
| -export([start_link/0, |
| check/0, check/1, |
| update/2]). |
| |
| %% gen_server callbacks |
| -export([init/1, |
| handle_call/3, |
| handle_cast/2, |
| handle_info/2, |
| terminate/2, |
| code_change/3]). |
| |
| -define(SERVER, ?MODULE). |
| |
| -record(state, {init=true, table_id}). |
| |
| %%%=================================================================== |
| %%% API |
| %%%=================================================================== |
| check() -> |
| gen_server:call(?MODULE, check). |
| |
| check(Counter) -> |
| gen_server:call(?MODULE, {check, Counter}). |
| |
| update(Counter, Value) -> |
| gen_server:cast(?MODULE, {update, Counter, Value}). |
| |
| %%-------------------------------------------------------------------- |
| %% @doc |
| %% Starts the server |
| %% |
| %% @spec start_link() -> {ok, Pid} | ignore | {error, Error} |
| %% @end |
| %%-------------------------------------------------------------------- |
| start_link() -> |
| gen_server:start_link({local, ?SERVER}, ?MODULE, [], []). |
| |
| %%%=================================================================== |
| %%% gen_server callbacks |
| %%%=================================================================== |
| |
| %%-------------------------------------------------------------------- |
| %% @private |
| %% @doc |
| %% Initializes the server |
| %% |
| %% @spec init(Args) -> {ok, State} | |
| %% {ok, State, Timeout} | |
| %% ignore | |
| %% {stop, Reason} |
| %% @end |
| %%-------------------------------------------------------------------- |
| init([]) -> |
| {ok, #state{}}. |
| |
| %%-------------------------------------------------------------------- |
| %% @private |
| %% @doc |
| %% Handling call messages |
| %% |
| %% @spec handle_call(Request, From, State) -> |
| %% {reply, Reply, State} | |
| %% {reply, Reply, State, Timeout} | |
| %% {noreply, State} | |
| %% {noreply, State, Timeout} | |
| %% {stop, Reason, Reply, State} | |
| %% {stop, Reason, State} |
| %% @end |
| %%-------------------------------------------------------------------- |
| handle_call(check, _From, State) -> |
| TableId = State#state.table_id, |
| {reply, {ok, ets:tab2list(TableId)}, State}; |
| handle_call({check, Counter}, _From, State) -> |
| TableId = State#state.table_id, |
| {reply, ets:lookup_element(TableId, Counter, 2), State}; |
| handle_call(_Request, _From, State) -> |
| Reply = ok, |
| {reply, Reply, State}. |
| |
| %%-------------------------------------------------------------------- |
| %% @private |
| %% @doc |
| %% Handling cast messages |
| %% |
| %% @spec handle_cast(Msg, State) -> {noreply, State} | |
| %% {noreply, State, Timeout} | |
| %% {stop, Reason, State} |
| %% @end |
| %%-------------------------------------------------------------------- |
| handle_cast({update, Counter, Value}, State) -> |
| TableId = State#state.table_id, |
| ets:update_counter(TableId, Counter, Value), |
| {noreply, State}; |
| handle_cast(_Msg, State) -> |
| {noreply, State}. |
| |
| %%-------------------------------------------------------------------- |
| %% @private |
| %% @doc |
| %% Handling all non call/cast messages |
| %% |
| %% @spec handle_info(Info, State) -> {noreply, State} | |
| %% {noreply, State, Timeout} | |
| %% {stop, Reason, State} |
| %% @end |
| %%-------------------------------------------------------------------- |
| handle_info({'ETS-TRANSFER', TableId, _Pid, _Data}, State) -> |
| {noreply, State#state{table_id=TableId}}; |
| handle_info(_Info, State) -> |
| {noreply, State}. |
| |
| %%-------------------------------------------------------------------- |
| %% @private |
| %% @doc |
| %% This function is called by a gen_server when it is about to |
| %% terminate. It should be the opposite of Module:init/1 and do any |
| %% necessary cleaning up. When it returns, the gen_server terminates |
| %% with Reason. The return value is ignored. |
| %% |
| %% @spec terminate(Reason, State) -> void() |
| %% @end |
| %%-------------------------------------------------------------------- |
| terminate(_Reason, _State) -> |
| ok. |
| |
| %%-------------------------------------------------------------------- |
| %% @private |
| %% @doc |
| %% Convert process state when code is changed |
| %% |
| %% @spec code_change(OldVsn, State, Extra) -> {ok, NewState} |
| %% @end |
| %%-------------------------------------------------------------------- |
| code_change(_OldVsn, State, _Extra) -> |
| {ok, State}. |
| |
| %%%=================================================================== |
| %%% Internal functions |
| %%%=================================================================== |
| |
| |