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Diffstat (limited to 'src/couch/src/couch_uuids.erl')
| -rw-r--r-- | src/couch/src/couch_uuids.erl | 188 |
1 files changed, 0 insertions, 188 deletions
diff --git a/src/couch/src/couch_uuids.erl b/src/couch/src/couch_uuids.erl deleted file mode 100644 index be6089dff..000000000 --- a/src/couch/src/couch_uuids.erl +++ /dev/null @@ -1,188 +0,0 @@ -% Licensed under the Apache License, Version 2.0 (the "License"); you may not -% use this file except in compliance with the License. You may obtain a copy of -% the License at -% -% http://www.apache.org/licenses/LICENSE-2.0 -% -% Unless required by applicable law or agreed to in writing, software -% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT -% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the -% License for the specific language governing permissions and limitations under -% the License. --module(couch_uuids). --include_lib("couch/include/couch_db.hrl"). - --behaviour(gen_server). --vsn(3). --behaviour(config_listener). - --export([start/0, stop/0]). --export([new/0, random/0]). - --export([init/1, terminate/2, code_change/3]). --export([handle_call/3, handle_cast/2, handle_info/2]). - -% config_listener api --export([handle_config_change/5, handle_config_terminate/3]). - --define(RELISTEN_DELAY, 5000). - -start() -> - gen_server:start_link({local, ?MODULE}, ?MODULE, [], []). - -stop() -> - gen_server:cast(?MODULE, stop). - -new() -> - gen_server:call(?MODULE, create). - -random() -> - list_to_binary(couch_util:to_hex(crypto:strong_rand_bytes(16))). - -init([]) -> - ok = config:listen_for_changes(?MODULE, nil), - {ok, state()}. - -terminate(_Reason, _State) -> - ok. - -handle_call(create, _From, random) -> - {reply, random(), random}; -handle_call(create, _From, {utc_random, ClockSeq}) -> - {UtcRandom, NewClockSeq} = utc_random(ClockSeq), - {reply, UtcRandom, {utc_random, NewClockSeq}}; -handle_call(create, _From, {utc_id, UtcIdSuffix, ClockSeq}) -> - Now = os:timestamp(), - {UtcId, NewClockSeq} = utc_suffix(UtcIdSuffix, ClockSeq, Now), - {reply, UtcId, {utc_id, UtcIdSuffix, NewClockSeq}}; -handle_call(create, _From, {sequential, Pref, Seq}) -> - Result = ?l2b(Pref ++ io_lib:format("~6.16.0b", [Seq])), - case Seq >= 16#fff000 of - true -> - {reply, Result, {sequential, new_prefix(), inc()}}; - _ -> - {reply, Result, {sequential, Pref, Seq + inc()}} - end. - -handle_cast(change, _State) -> - {noreply, state()}; -handle_cast(stop, State) -> - {stop, normal, State}; -handle_cast(_Msg, State) -> - {noreply, State}. - -handle_info(restart_config_listener, State) -> - ok = config:listen_for_changes(?MODULE, nil), - {noreply, State}; -handle_info(_Info, State) -> - {noreply, State}. - -code_change(_OldVsn, State, _Extra) -> - {ok, State}. - -handle_config_change("uuids", _, _, _, _) -> - {ok, gen_server:cast(?MODULE, change)}; -handle_config_change(_, _, _, _, _) -> - {ok, nil}. - -handle_config_terminate(_, stop, _) -> - ok; -handle_config_terminate(_Server, _Reason, _State) -> - gen_server:cast(?MODULE, change), - erlang:send_after(?RELISTEN_DELAY, whereis(?MODULE), restart_config_listener). - -new_prefix() -> - couch_util:to_hex((crypto:strong_rand_bytes(13))). - -inc() -> - couch_rand:uniform(16#ffd). - -state() -> - AlgoStr = config:get("uuids", "algorithm", "sequential"), - case couch_util:to_existing_atom(AlgoStr) of - random -> - random; - utc_random -> - ClockSeq = micros_since_epoch(os:timestamp()), - {utc_random, ClockSeq}; - utc_id -> - ClockSeq = micros_since_epoch(os:timestamp()), - UtcIdSuffix = config:get("uuids", "utc_id_suffix", ""), - {utc_id, UtcIdSuffix, ClockSeq}; - sequential -> - {sequential, new_prefix(), inc()}; - Unknown -> - throw({unknown_uuid_algorithm, Unknown}) - end. - -micros_since_epoch({_, _, Micro} = Now) -> - Nowish = calendar:now_to_universal_time(Now), - Nowsecs = calendar:datetime_to_gregorian_seconds(Nowish), - Then = calendar:datetime_to_gregorian_seconds({{1970, 1, 1}, {0, 0, 0}}), - (Nowsecs - Then) * 1000000 + Micro. - -utc_random(ClockSeq) -> - Suffix = couch_util:to_hex(crypto:strong_rand_bytes(9)), - utc_suffix(Suffix, ClockSeq, os:timestamp()). - -utc_suffix(Suffix, ClockSeq, Now) -> - OsMicros = micros_since_epoch(Now), - NewClockSeq = - if - OsMicros =< ClockSeq -> - % Timestamp is lagging, use ClockSeq as Timestamp - ClockSeq + 1; - OsMicros > ClockSeq -> - % Timestamp advanced, use it, and reset ClockSeq with it - OsMicros - end, - Prefix = io_lib:format("~14.16.0b", [NewClockSeq]), - {list_to_binary(Prefix ++ Suffix), NewClockSeq}. - --ifdef(TEST). - --include_lib("eunit/include/eunit.hrl"). - -utc_id_time_does_not_advance_test() -> - % Timestamp didn't advance but local clock sequence should and new UUIds - % should be generated - Now = {0, 1, 2}, - ClockSeq0 = micros_since_epoch({3, 4, 5}), - {UtcId0, ClockSeq1} = utc_suffix("", ClockSeq0, Now), - ?assert(is_binary(UtcId0)), - ?assertEqual(ClockSeq0 + 1, ClockSeq1), - {UtcId1, ClockSeq2} = utc_suffix("", ClockSeq1, Now), - ?assertNotEqual(UtcId0, UtcId1), - ?assertEqual(ClockSeq1 + 1, ClockSeq2). - -utc_id_time_advanced_test() -> - % Timestamp advanced, a new UUID generated and also the last clock sequence - % is updated to that timestamp. - Now0 = {0, 1, 2}, - ClockSeq0 = micros_since_epoch({3, 4, 5}), - {UtcId0, ClockSeq1} = utc_suffix("", ClockSeq0, Now0), - ?assert(is_binary(UtcId0)), - ?assertEqual(ClockSeq0 + 1, ClockSeq1), - Now1 = {9, 9, 9}, - {UtcId1, ClockSeq2} = utc_suffix("", ClockSeq1, Now1), - ?assert(is_binary(UtcId1)), - ?assertNotEqual(UtcId0, UtcId1), - ?assertEqual(micros_since_epoch(Now1), ClockSeq2). - -utc_random_test_time_does_not_advance_test() -> - {MSec, Sec, USec} = os:timestamp(), - Future = {MSec + 10, Sec, USec}, - ClockSeqFuture = micros_since_epoch(Future), - {UtcRandom, NextClockSeq} = utc_random(ClockSeqFuture), - ?assert(is_binary(UtcRandom)), - ?assertEqual(32, byte_size(UtcRandom)), - ?assertEqual(ClockSeqFuture + 1, NextClockSeq). - -utc_random_test_time_advance_test() -> - ClockSeqPast = micros_since_epoch({1, 1, 1}), - {UtcRandom, NextClockSeq} = utc_random(ClockSeqPast), - ?assert(is_binary(UtcRandom)), - ?assertEqual(32, byte_size(UtcRandom)), - ?assert(NextClockSeq > micros_since_epoch({1000, 0, 0})). - --endif. |