%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1997-2015. All Rights Reserved.
%%
%% 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.
%%
%% %CopyrightEnd%
%%
-module(disk_log).
%% Efficient file based log - process part
-export([start/0, istart_link/1,
log/2, log_terms/2, blog/2, blog_terms/2,
alog/2, alog_terms/2, balog/2, balog_terms/2,
close/1, lclose/1, lclose/2, sync/1, open/1,
truncate/1, truncate/2, btruncate/2,
reopen/2, reopen/3, breopen/3, inc_wrap_file/1, change_size/2,
change_notify/3, change_header/2,
chunk/2, chunk/3, bchunk/2, bchunk/3, chunk_step/3, chunk_info/1,
block/1, block/2, unblock/1, info/1, format_error/1,
accessible_logs/0]).
%% Internal exports
-export([init/2, internal_open/2,
system_continue/3, system_terminate/4, system_code_change/4]).
%% To be used by disk_log_h.erl (not (yet) in Erlang/OTP) only.
-export([ll_open/1, ll_close/1, do_log/2, do_sync/1, do_info/2]).
%% To be used by wrap_log_reader only.
-export([ichunk_end/2]).
%% To be used for debugging only:
-export([pid2name/1]).
-export_type([continuation/0]).
-type dlog_state_error() :: 'ok' | {'error', term()}.
-record(state, {queue = [],
messages = [],
parent,
server,
cnt = 0 :: non_neg_integer(),
args,
error_status = ok :: dlog_state_error(),
cache_error = ok %% cache write error after timeout
}).
-include("disk_log.hrl").
-define(failure(Error, Function, Arg),
{{failed, Error}, [{?MODULE, Function, Arg}]}).
%%-define(PROFILE(C), C).
-define(PROFILE(C), void).
-compile({inline,[{log_loop,6},{log_end_sync,2},{replies,2},{rflat,1}]}).
%%%----------------------------------------------------------------------
%%% Contract type specifications
%%%----------------------------------------------------------------------
-opaque continuation() :: #continuation{}.
-type bytes() :: binary() | [byte()].
-type file_error() :: term(). % XXX: refine
-type invalid_header() :: term(). % XXX: refine
%%%----------------------------------------------------------------------
%%% API
%%%----------------------------------------------------------------------
%%-----------------------------------------------------------------
%% This module implements the API, and the processes for each log.
%% There is one process per log.
%%-----------------------------------------------------------------
-type open_error_rsn() :: 'no_such_log'
| {'badarg', term()}
| {'size_mismatch', CurrentSize :: dlog_size(),
NewSize :: dlog_size()}
| {'arg_mismatch', OptionName :: dlog_optattr(),
CurrentValue :: term(), Value :: term()}
| {'name_already_open', Log :: log()}
| {'open_read_write', Log :: log()}
| {'open_read_only', Log :: log()}
| {'need_repair', Log :: log()}
| {'not_a_log_file', FileName :: file:filename()}
| {'invalid_index_file', FileName :: file:filename()}
| {'invalid_header', invalid_header()}
| {'file_error', file:filename(), file_error()}
| {'node_already_open', Log :: log()}.
-type dist_error_rsn() :: 'nodedown' | open_error_rsn().
-type ret() :: {'ok', Log :: log()}
| {'repaired', Log :: log(),
{'recovered', Rec :: non_neg_integer()},
{'badbytes', Bad :: non_neg_integer()}}.
-type open_ret() :: ret() | {'error', open_error_rsn()}.
-type dist_open_ret() :: {[{node(), ret()}],
[{node(), {'error', dist_error_rsn()}}]}.
-spec open(ArgL) -> open_ret() | dist_open_ret() when
ArgL :: dlog_options().
open(A) ->
disk_log_server:open(check_arg(A, #arg{options = A})).
-type log_error_rsn() :: 'no_such_log' | 'nonode' | {'read_only_mode', log()}
| {'format_external', log()} | {'blocked_log', log()}
| {'full', log()} | {'invalid_header', invalid_header()}
| {'file_error', file:filename(), file_error()}.
-spec log(Log, Term) -> ok | {error, Reason :: log_error_rsn()} when
Log :: log(),
Term :: term().
log(Log, Term) ->
req(Log, {log, term_to_binary(Term)}).
-spec blog(Log, Bytes) -> ok | {error, Reason :: log_error_rsn()} when
Log :: log(),
Bytes :: bytes().
blog(Log, Bytes) ->
req(Log, {blog, ensure_binary(Bytes)}).
-spec log_terms(Log, TermList) -> ok | {error, Resaon :: log_error_rsn()} when
Log :: log(),
TermList :: [term()].
log_terms(Log, Terms) ->
Bs = terms2bins(Terms),
req(Log, {log, Bs}).
-spec blog_terms(Log, BytesList) ->
ok | {error, Reason :: log_error_rsn()} when
Log :: log(),
BytesList :: [bytes()].
blog_terms(Log, Bytess) ->
Bs = ensure_binary_list(Bytess),
req(Log, {blog, Bs}).
-type notify_ret() :: 'ok' | {'error', 'no_such_log'}.
-spec alog(Log, Term) -> notify_ret() when
Log :: log(),
Term :: term().
alog(Log, Term) ->
notify(Log, {alog, term_to_binary(Term)}).
-spec alog_terms(Log, TermList) -> notify_ret() when
Log :: log(),
TermList :: [term()].
alog_terms(Log, Terms) ->
Bs = terms2bins(Terms),
notify(Log, {alog, Bs}).
-spec balog(Log, Bytes) -> notify_ret() when
Log :: log(),
Bytes :: bytes().
balog(Log, Bytes) ->
notify(Log, {balog, ensure_binary(Bytes)}).
-spec balog_terms(Log, ByteList) -> notify_ret() when
Log :: log(),
ByteList :: [bytes()].
balog_terms(Log, Bytess) ->
Bs = ensure_binary_list(Bytess),
notify(Log, {balog, Bs}).
-type close_error_rsn() ::'no_such_log' | 'nonode'
| {'file_error', file:filename(), file_error()}.
-spec close(Log) -> 'ok' | {'error', close_error_rsn()} when
Log :: log().
close(Log) ->
req(Log, close).
-type lclose_error_rsn() :: 'no_such_log'
| {'file_error', file:filename(), file_error()}.
-spec lclose(Log) -> 'ok' | {'error', lclose_error_rsn()} when
Log :: log().
lclose(Log) ->
lclose(Log, node()).
-spec lclose(Log, Node) -> 'ok' | {'error', lclose_error_rsn()} when
Log :: log(),
Node :: node().
lclose(Log, Node) ->
lreq(Log, close, Node).
-type trunc_error_rsn() :: 'no_such_log' | 'nonode'
| {'read_only_mode', log()}
| {'blocked_log', log()}
| {'invalid_header', invalid_header()}
| {'file_error', file:filename(), file_error()}.
-spec truncate(Log) -> 'ok' | {'error', trunc_error_rsn()} when
Log :: log().
truncate(Log) ->
req(Log, {truncate, none, truncate, 1}).
-spec truncate(Log, Head) -> 'ok' | {'error', trunc_error_rsn()} when
Log :: log(),
Head :: term().
truncate(Log, Head) ->
req(Log, {truncate, {ok, term_to_binary(Head)}, truncate, 2}).
-spec btruncate(Log, BHead) -> 'ok' | {'error', trunc_error_rsn()} when
Log :: log(),
BHead :: bytes().
btruncate(Log, Head) ->
req(Log, {truncate, {ok, ensure_binary(Head)}, btruncate, 2}).
-type reopen_error_rsn() :: no_such_log
| nonode
| {read_only_mode, log()}
| {blocked_log, log()}
| {same_file_name, log()} |
{invalid_index_file, file:filename()}
| {invalid_header, invalid_header()}
| {'file_error', file:filename(), file_error()}.
-spec reopen(Log, File) -> 'ok' | {'error', reopen_error_rsn()} when
Log :: log(),
File :: file:filename().
reopen(Log, NewFile) ->
req(Log, {reopen, NewFile, none, reopen, 2}).
-spec reopen(Log, File, Head) -> 'ok' | {'error', reopen_error_rsn()} when
Log :: log(),
File :: file:filename(),
Head :: term().
reopen(Log, NewFile, NewHead) ->
req(Log, {reopen, NewFile, {ok, term_to_binary(NewHead)}, reopen, 3}).
-spec breopen(Log, File, BHead) -> 'ok' | {'error', reopen_error_rsn()} when
Log :: log(),
File :: file:filename(),
BHead :: bytes().
breopen(Log, NewFile, NewHead) ->
req(Log, {reopen, NewFile, {ok, ensure_binary(NewHead)}, breopen, 3}).
-type inc_wrap_error_rsn() :: 'no_such_log' | 'nonode'
| {'read_only_mode', log()}
| {'blocked_log', log()} | {'halt_log', log()}
| {'invalid_header', invalid_header()}
| {'file_error', file:filename(), file_error()}.
-spec inc_wrap_file(Log) -> 'ok' | {'error', inc_wrap_error_rsn()} when
Log :: log().
inc_wrap_file(Log) ->
req(Log, inc_wrap_file).
-spec change_size(Log, Size) -> 'ok' | {'error', Reason} when
Log :: log(),
Size :: dlog_size(),
Reason :: no_such_log | nonode | {read_only_mode, Log}
| {blocked_log, Log}
| {new_size_too_small, CurrentSize :: pos_integer()}
| {badarg, size}
| {file_error, file:filename(), file_error()}.
change_size(Log, NewSize) ->
req(Log, {change_size, NewSize}).
-spec change_notify(Log, Owner, Notify) -> 'ok' | {'error', Reason} when
Log :: log(),
Owner :: pid(),
Notify :: boolean(),
Reason :: no_such_log | nonode | {blocked_log, Log}
| {badarg, notify} | {not_owner, Owner}.
change_notify(Log, Pid, NewNotify) ->
req(Log, {change_notify, Pid, NewNotify}).
-spec change_header(Log, Header) -> 'ok' | {'error', Reason} when
Log :: log(),
Header :: {head, dlog_head_opt()}
| {head_func, MFA :: {atom(), atom(), list()}},
Reason :: no_such_log | nonode | {read_only_mode, Log}
| {blocked_log, Log} | {badarg, head}.
change_header(Log, NewHead) ->
req(Log, {change_header, NewHead}).
-type sync_error_rsn() :: 'no_such_log' | 'nonode' | {'read_only_mode', log()}
| {'blocked_log', log()}
| {'file_error', file:filename(), file_error()}.
-spec sync(Log) -> 'ok' | {'error', sync_error_rsn()} when
Log :: log().
sync(Log) ->
req(Log, sync).
-type block_error_rsn() :: 'no_such_log' | 'nonode' | {'blocked_log', log()}.
-spec block(Log) -> 'ok' | {'error', block_error_rsn()} when
Log :: log().
block(Log) ->
block(Log, true).
-spec block(Log, QueueLogRecords) -> 'ok' | {'error', block_error_rsn()} when
Log :: log(),
QueueLogRecords :: boolean().
block(Log, QueueLogRecords) ->
req(Log, {block, QueueLogRecords}).
-type unblock_error_rsn() :: 'no_such_log' | 'nonode'
| {'not_blocked', log()}
| {'not_blocked_by_pid', log()}.
-spec unblock(Log) -> 'ok' | {'error', unblock_error_rsn()} when
Log :: log().
unblock(Log) ->
req(Log, unblock).
-spec format_error(Error) -> io_lib:chars() when
Error :: term().
format_error(Error) ->
do_format_error(Error).
-type dlog_info() :: {name, Log :: log()}
| {file, File :: file:filename()}
| {type, Type :: dlog_type()}
| {format, Format :: dlog_format()}
| {size, Size :: dlog_size()}
| {mode, Mode :: dlog_mode()}
| {owners, [{pid(), Notify :: boolean()}]}
| {users, Users :: non_neg_integer()}
| {status, Status ::
ok | {blocked, QueueLogRecords :: boolean()}}
| {node, Node :: node()}
| {distributed, Dist :: local | [node()]}
| {head, Head :: none
| {head, term()}
| (MFA :: {atom(), atom(), list()})}
| {no_written_items, NoWrittenItems ::non_neg_integer()}
| {full, Full :: boolean}
| {no_current_bytes, non_neg_integer()}
| {no_current_items, non_neg_integer()}
| {no_items, non_neg_integer()}
| {current_file, pos_integer()}
| {no_overflows, {SinceLogWasOpened :: non_neg_integer(),
SinceLastInfo :: non_neg_integer()}}.
-spec info(Log) -> InfoList | {'error', no_such_log} when
Log :: log(),
InfoList :: [dlog_info()].
info(Log) ->
sreq(Log, info).
-spec pid2name(Pid) -> {'ok', Log} | 'undefined' when
Pid :: pid(),
Log :: log().
pid2name(Pid) ->
disk_log_server:start(),
case ets:lookup(?DISK_LOG_PID_TABLE, Pid) of
[] -> undefined;
[{_Pid, Log}] -> {ok, Log}
end.
%% This function Takes 3 args, a Log, a Continuation and N.
%% It retuns a {Cont2, ObjList} | eof | {error, Reason}
%% The initial continuation is the atom 'start'
-type chunk_error_rsn() :: no_such_log
| {format_external, log()}
| {blocked_log, log()}
| {badarg, continuation}
| {not_internal_wrap, log()}
| {corrupt_log_file, FileName :: file:filename()}
| {file_error, file:filename(), file_error()}.
-type chunk_ret() :: {Continuation2 :: continuation(), Terms :: [term()]}
| {Continuation2 :: continuation(),
Terms :: [term()],
Badbytes :: non_neg_integer()}
| eof
| {error, Reason :: chunk_error_rsn()}.
-spec chunk(Log, Continuation) -> chunk_ret() when
Log :: log(),
Continuation :: start | continuation().
chunk(Log, Cont) ->
chunk(Log, Cont, infinity).
-spec chunk(Log, Continuation, N) -> chunk_ret() when
Log :: log(),
Continuation :: start | continuation(),
N :: pos_integer() | infinity.
chunk(Log, Cont, infinity) ->
%% There cannot be more than ?MAX_CHUNK_SIZE terms in a chunk.
ichunk(Log, Cont, ?MAX_CHUNK_SIZE);
chunk(Log, Cont, N) when is_integer(N), N > 0 ->
ichunk(Log, Cont, N).
ichunk(Log, start, N) ->
R = sreq(Log, {chunk, 0, [], N}),
ichunk_end(R, Log);
ichunk(Log, More, N) when is_record(More, continuation) ->
R = req2(More#continuation.pid,
{chunk, More#continuation.pos, More#continuation.b, N}),
ichunk_end(R, Log);
ichunk(_Log, _, _) ->
{error, {badarg, continuation}}.
ichunk_end({C, R}, Log) when is_record(C, continuation) ->
ichunk_end(R, read_write, Log, C, 0);
ichunk_end({C, R, Bad}, Log) when is_record(C, continuation) ->
ichunk_end(R, read_only, Log, C, Bad);
ichunk_end(R, _Log) ->
R.
%% Create the terms on the client's heap, not the server's.
%% The list of binaries is reversed.
ichunk_end(R, Mode, Log, C, Bad) ->
case catch bins2terms(R, []) of
{'EXIT', _} ->
RR = lists:reverse(R),
ichunk_bad_end(RR, Mode, Log, C, Bad, []);
Ts when Bad > 0 ->
{C, Ts, Bad};
Ts when Bad =:= 0 ->
{C, Ts}
end.
bins2terms([], L) ->
L;
bins2terms([B | Bs], L) ->
bins2terms(Bs, [binary_to_term(B) | L]).
ichunk_bad_end([B | Bs], Mode, Log, C, Bad, A) ->
case catch binary_to_term(B) of
{'EXIT', _} when read_write =:= Mode ->
InfoList = info(Log),
{value, {file, FileName}} = lists:keysearch(file, 1, InfoList),
File = case C#continuation.pos of
Pos when is_integer(Pos) -> FileName; % halt log
{FileNo, _} -> add_ext(FileName, FileNo) % wrap log
end,
{error, {corrupt_log_file, File}};
{'EXIT', _} when read_only =:= Mode ->
Reread = lists:foldl(fun(Bin, Sz) ->
Sz + byte_size(Bin) + ?HEADERSZ
end, 0, Bs),
NewPos = case C#continuation.pos of
Pos when is_integer(Pos) -> Pos-Reread;
{FileNo, Pos} -> {FileNo, Pos-Reread}
end,
NewBad = Bad + byte_size(B),
{C#continuation{pos = NewPos, b = []}, lists:reverse(A), NewBad};
T ->
ichunk_bad_end(Bs, Mode, Log, C, Bad, [T | A])
end.
-type bchunk_ret() :: {Continuation2 :: continuation(),
Binaries :: [binary()]}
| {Continuation2 :: continuation(),
Binaries :: [binary()],
Badbytes :: non_neg_integer()}
| eof
| {error, Reason :: chunk_error_rsn()}.
-spec bchunk(Log, Continuation) -> bchunk_ret() when
Log :: log(),
Continuation :: start | continuation().
bchunk(Log, Cont) ->
bchunk(Log, Cont, infinity).
-spec bchunk(Log, Continuation, N) -> bchunk_ret() when
Log :: log(),
Continuation :: start | continuation(),
N :: pos_integer() | infinity.
bchunk(Log, Cont, infinity) ->
%% There cannot be more than ?MAX_CHUNK_SIZE terms in a chunk.
bichunk(Log, Cont, ?MAX_CHUNK_SIZE);
bchunk(Log, Cont, N) when is_integer(N), N > 0 ->
bichunk(Log, Cont, N).
bichunk(Log, start, N) ->
R = sreq(Log, {chunk, 0, [], N}),
bichunk_end(R);
bichunk(_Log, #continuation{pid = Pid, pos = Pos, b = B}, N) ->
R = req2(Pid, {chunk, Pos, B, N}),
bichunk_end(R);
bichunk(_Log, _, _) ->
{error, {badarg, continuation}}.
bichunk_end({C = #continuation{}, R}) ->
{C, lists:reverse(R)};
bichunk_end({C = #continuation{}, R, Bad}) ->
{C, lists:reverse(R), Bad};
bichunk_end(R) ->
R.
-spec chunk_step(Log, Continuation, Step) ->
{'ok', any()} | {'error', Reason} when
Log :: log(),
Continuation :: start | continuation(),
Step :: integer(),
Reason :: no_such_log | end_of_log | {format_external, Log}
| {blocked_log, Log} | {badarg, continuation}
| {file_error, file:filename(), file_error()}.
chunk_step(Log, Cont, N) when is_integer(N) ->
ichunk_step(Log, Cont, N).
ichunk_step(Log, start, N) ->
sreq(Log, {chunk_step, 0, N});
ichunk_step(_Log, More, N) when is_record(More, continuation) ->
req2(More#continuation.pid, {chunk_step, More#continuation.pos, N});
ichunk_step(_Log, _, _) ->
{error, {badarg, continuation}}.
-spec chunk_info(Continuation) -> InfoList | {error, Reason} when
Continuation :: continuation(),
InfoList :: [{node, Node :: node()}, ...],
Reason :: {no_continuation, Continuation}.
chunk_info(More = #continuation{}) ->
[{node, node(More#continuation.pid)}];
chunk_info(BadCont) ->
{error, {no_continuation, BadCont}}.
-spec accessible_logs() -> {[LocalLog], [DistributedLog]} when
LocalLog :: log(),
DistributedLog :: log().
accessible_logs() ->
disk_log_server:accessible_logs().
istart_link(Server) ->
{ok, proc_lib:spawn_link(disk_log, init, [self(), Server])}.
%% Only for backwards compatibility, could probably be removed.
-spec start() -> 'ok'.
start() ->
disk_log_server:start().
internal_open(Pid, A) ->
req2(Pid, {internal_open, A}).
%%% ll_open() and ll_close() are used by disk_log_h.erl, a module not
%%% (yet) in Erlang/OTP.
%% -spec ll_open(dlog_options()) -> {'ok', Res :: _, #log{}, Cnt :: _} | Error.
ll_open(A) ->
case check_arg(A, #arg{options = A}) of
{ok, L} -> do_open(L);
Error -> Error
end.
%% -> closed | throw(Error)
ll_close(Log) ->
close_disk_log2(Log).
check_arg([], Res) ->
Ret = case Res#arg.head of
none ->
{ok, Res};
_ ->
case check_head(Res#arg.head, Res#arg.format) of
{ok, Head} ->
{ok, Res#arg{head = Head}};
Error ->
Error
end
end,
if %% check result
Res#arg.name =:= 0 ->
{error, {badarg, name}};
Res#arg.file =:= none ->
case catch lists:concat([Res#arg.name, ".LOG"]) of
{'EXIT',_} -> {error, {badarg, file}};
FName -> check_arg([], Res#arg{file = FName})
end;
Res#arg.repair =:= truncate, Res#arg.mode =:= read_only ->
{error, {badarg, repair_read_only}};
Res#arg.type =:= halt, is_tuple(Res#arg.size) ->
{error, {badarg, size}};
Res#arg.type =:= wrap ->
{OldSize, Version} =
disk_log_1:read_size_file_version(Res#arg.file),
check_wrap_arg(Ret, OldSize, Version);
true ->
Ret
end;
check_arg([{file, F} | Tail], Res) when is_list(F) ->
check_arg(Tail, Res#arg{file = F});
check_arg([{file, F} | Tail], Res) when is_atom(F) ->
check_arg(Tail, Res#arg{file = F});
check_arg([{linkto, Pid} |Tail], Res) when is_pid(Pid) ->
check_arg(Tail, Res#arg{linkto = Pid});
check_arg([{linkto, none} |Tail], Res) ->
check_arg(Tail, Res#arg{linkto = none});
check_arg([{name, Name}|Tail], Res) ->
check_arg(Tail, Res#arg{name = Name});
check_arg([{repair, true}|Tail], Res) ->
check_arg(Tail, Res#arg{repair = true});
check_arg([{repair, false}|Tail], Res) ->
check_arg(Tail, Res#arg{repair = false});
check_arg([{repair, truncate}|Tail], Res) ->
check_arg(Tail, Res#arg{repair = truncate});
check_arg([{size, Int}|Tail], Res) when is_integer(Int), Int > 0 ->
check_arg(Tail, Res#arg{size = Int});
check_arg([{size, infinity}|Tail], Res) ->
check_arg(Tail, Res#arg{size = infinity});
check_arg([{size, {MaxB,MaxF}}|Tail], Res) when is_integer(MaxB),
is_integer(MaxF),
MaxB > 0, MaxB =< ?MAX_BYTES,
MaxF > 0, MaxF < ?MAX_FILES ->
check_arg(Tail, Res#arg{size = {MaxB, MaxF}});
check_arg([{type, wrap}|Tail], Res) ->
check_arg(Tail, Res#arg{type = wrap});
check_arg([{type, halt}|Tail], Res) ->
check_arg(Tail, Res#arg{type = halt});
check_arg([{format, internal}|Tail], Res) ->
check_arg(Tail, Res#arg{format = internal});
check_arg([{format, external}|Tail], Res) ->
check_arg(Tail, Res#arg{format = external});
check_arg([{distributed, []}|Tail], Res) ->
check_arg(Tail, Res#arg{distributed = false});
check_arg([{distributed, Nodes}|Tail], Res) when is_list(Nodes) ->
check_arg(Tail, Res#arg{distributed = {true, Nodes}});
check_arg([{notify, true}|Tail], Res) ->
check_arg(Tail, Res#arg{notify = true});
check_arg([{notify, false}|Tail], Res) ->
check_arg(Tail, Res#arg{notify = false});
check_arg([{head_func, HeadFunc}|Tail], Res) ->
check_arg(Tail, Res#arg{head = {head_func, HeadFunc}});
check_arg([{head, Term}|Tail], Res) ->
check_arg(Tail, Res#arg{head = {head, Term}});
check_arg([{mode, read_only}|Tail], Res) ->
check_arg(Tail, Res#arg{mode = read_only});
check_arg([{mode, read_write}|Tail], Res) ->
check_arg(Tail, Res#arg{mode = read_write});
check_arg(Arg, _) ->
{error, {badarg, Arg}}.
check_wrap_arg({ok, Res}, {0,0}, _Version) when Res#arg.size =:= infinity ->
{error, {badarg, size}};
check_wrap_arg({ok, Res}, OldSize, Version) when Res#arg.size =:= infinity ->
NewRes = Res#arg{size = OldSize},
check_wrap_arg({ok, NewRes}, OldSize, Version);
check_wrap_arg({ok, Res}, {0,0}, Version) ->
{ok, Res#arg{version = Version}};
check_wrap_arg({ok, Res}, OldSize, Version) when OldSize =:= Res#arg.size ->
{ok, Res#arg{version = Version}};
check_wrap_arg({ok, Res}, _OldSize, Version) when Res#arg.repair =:= truncate,
is_tuple(Res#arg.size) ->
{ok, Res#arg{version = Version}};
check_wrap_arg({ok, Res}, OldSize, _Version) when is_tuple(Res#arg.size) ->
{error, {size_mismatch, OldSize, Res#arg.size}};
check_wrap_arg({ok, _Res}, _OldSize, _Version) ->
{error, {badarg, size}};
check_wrap_arg(Ret, _OldSize, _Version) ->
Ret.
%%%-----------------------------------------------------------------
%%% Server functions
%%%-----------------------------------------------------------------
init(Parent, Server) ->
?PROFILE(ep:do()),
process_flag(trap_exit, true),
loop(#state{parent = Parent, server = Server}).
loop(State) when State#state.messages =:= [] ->
receive
Message ->
handle(Message, State)
end;
loop(State) ->
[M | Ms] = State#state.messages,
handle(M, State#state{messages = Ms}).
handle({From, write_cache}, S) when From =:= self() ->
case catch do_write_cache(get(log)) of
ok ->
loop(S);
Error ->
loop(S#state{cache_error = Error})
end;
handle({From, {log, B}}=Message, S) ->
case get(log) of
L when L#log.mode =:= read_only ->
reply(From, {error, {read_only_mode, L#log.name}}, S);
L when L#log.status =:= ok, L#log.format =:= internal ->
log_loop(S, From, [B], []);
L when L#log.status =:= ok, L#log.format =:= external ->
reply(From, {error, {format_external, L#log.name}}, S);
L when L#log.status =:= {blocked, false} ->
reply(From, {error, {blocked_log, L#log.name}}, S);
L when L#log.blocked_by =:= From ->
reply(From, {error, {blocked_log, L#log.name}}, S);
_ ->
enqueue(Message, S)
end;
handle({From, {blog, B}}=Message, S) ->
case get(log) of
L when L#log.mode =:= read_only ->
reply(From, {error, {read_only_mode, L#log.name}}, S);
L when L#log.status =:= ok ->
log_loop(S, From, [B], []);
L when L#log.status =:= {blocked, false} ->
reply(From, {error, {blocked_log, L#log.name}}, S);
L when L#log.blocked_by =:= From ->
reply(From, {error, {blocked_log, L#log.name}}, S);
_ ->
enqueue(Message, S)
end;
handle({alog, B}=Message, S) ->
case get(log) of
L when L#log.mode =:= read_only ->
notify_owners({read_only,B}),
loop(S);
L when L#log.status =:= ok, L#log.format =:= internal ->
log_loop(S, [], [B], []);
L when L#log.status =:= ok ->
notify_owners({format_external, B}),
loop(S);
L when L#log.status =:= {blocked, false} ->
notify_owners({blocked_log, B}),
loop(S);
_ ->
enqueue(Message, S)
end;
handle({balog, B}=Message, S) ->
case get(log) of
L when L#log.mode =:= read_only ->
notify_owners({read_only,B}),
loop(S);
L when L#log.status =:= ok ->
log_loop(S, [], [B], []);
L when L#log.status =:= {blocked, false} ->
notify_owners({blocked_log, B}),
loop(S);
_ ->
enqueue(Message, S)
end;
handle({From, {block, QueueLogRecs}}=Message, S) ->
case get(log) of
L when L#log.status =:= ok ->
do_block(From, QueueLogRecs, L),
reply(From, ok, S);
L when L#log.status =:= {blocked, false} ->
reply(From, {error, {blocked_log, L#log.name}}, S);
L when L#log.blocked_by =:= From ->
reply(From, {error, {blocked_log, L#log.name}}, S);
_ ->
enqueue(Message, S)
end;
handle({From, unblock}, S) ->
case get(log) of
L when L#log.status =:= ok ->
reply(From, {error, {not_blocked, L#log.name}}, S);
L when L#log.blocked_by =:= From ->
S2 = do_unblock(L, S),
reply(From, ok, S2);
L ->
reply(From, {error, {not_blocked_by_pid, L#log.name}}, S)
end;
handle({From, sync}=Message, S) ->
case get(log) of
L when L#log.mode =:= read_only ->
reply(From, {error, {read_only_mode, L#log.name}}, S);
L when L#log.status =:= ok ->
log_loop(S, [], [], [From]);
L when L#log.status =:= {blocked, false} ->
reply(From, {error, {blocked_log, L#log.name}}, S);
L when L#log.blocked_by =:= From ->
reply(From, {error, {blocked_log, L#log.name}}, S);
_ ->
enqueue(Message, S)
end;
handle({From, {truncate, Head, F, A}}=Message, S) ->
case get(log) of
L when L#log.mode =:= read_only ->
reply(From, {error, {read_only_mode, L#log.name}}, S);
L when L#log.status =:= ok, S#state.cache_error =/= ok ->
loop(cache_error(S, [From]));
L when L#log.status =:= ok ->
H = merge_head(Head, L#log.head),
case catch do_trunc(L, H) of
ok ->
erase(is_full),
notify_owners({truncated, S#state.cnt}),
N = if Head =:= none -> 0; true -> 1 end,
reply(From, ok, (state_ok(S))#state{cnt = N});
Error ->
do_exit(S, From, Error, ?failure(Error, F, A))
end;
L when L#log.status =:= {blocked, false} ->
reply(From, {error, {blocked_log, L#log.name}}, S);
L when L#log.blocked_by =:= From ->
reply(From, {error, {blocked_log, L#log.name}}, S);
_ ->
enqueue(Message, S)
end;
handle({From, {chunk, Pos, B, N}}=Message, S) ->
case get(log) of
L when L#log.status =:= ok, S#state.cache_error =/= ok ->
loop(cache_error(S, [From]));
L when L#log.status =:= ok ->
R = do_chunk(L, Pos, B, N),
reply(From, R, S);
L when L#log.blocked_by =:= From ->
R = do_chunk(L, Pos, B, N),
reply(From, R, S);
L when L#log.status =:= {blocked, false} ->
reply(From, {error, {blocked_log, L#log.name}}, S);
_L ->
enqueue(Message, S)
end;
handle({From, {chunk_step, Pos, N}}=Message, S) ->
case get(log) of
L when L#log.status =:= ok, S#state.cache_error =/= ok ->
loop(cache_error(S, [From]));
L when L#log.status =:= ok ->
R = do_chunk_step(L, Pos, N),
reply(From, R, S);
L when L#log.blocked_by =:= From ->
R = do_chunk_step(L, Pos, N),
reply(From, R, S);
L when L#log.status =:= {blocked, false} ->
reply(From, {error, {blocked_log, L#log.name}}, S);
_ ->
enqueue(Message, S)
end;
handle({From, {change_notify, Pid, NewNotify}}=Message, S) ->
case get(log) of
L when L#log.status =:= ok ->
case do_change_notify(L, Pid, NewNotify) of
{ok, L1} ->
put(log, L1),
reply(From, ok, S);
Error ->
reply(From, Error, S)
end;
L when L#log.status =:= {blocked, false} ->
reply(From, {error, {blocked_log, L#log.name}}, S);
L when L#log.blocked_by =:= From ->
reply(From, {error, {blocked_log, L#log.name}}, S);
_ ->
enqueue(Message, S)
end;
handle({From, {change_header, NewHead}}=Message, S) ->
case get(log) of
L when L#log.mode =:= read_only ->
reply(From, {error, {read_only_mode, L#log.name}}, S);
L when L#log.status =:= ok ->
case check_head(NewHead, L#log.format) of
{ok, Head} ->
put(log, L#log{head = mk_head(Head, L#log.format)}),
reply(From, ok, S);
Error ->
reply(From, Error, S)
end;
L when L#log.status =:= {blocked, false} ->
reply(From, {error, {blocked_log, L#log.name}}, S);
L when L#log.blocked_by =:= From ->
reply(From, {error, {blocked_log, L#log.name}}, S);
_ ->
enqueue(Message, S)
end;
handle({From, {change_size, NewSize}}=Message, S) ->
case get(log) of
L when L#log.mode =:= read_only ->
reply(From, {error, {read_only_mode, L#log.name}}, S);
L when L#log.status =:= ok ->
case check_size(L#log.type, NewSize) of
ok ->
case catch do_change_size(L, NewSize) of % does the put
ok ->
reply(From, ok, S);
{big, CurSize} ->
reply(From,
{error,
{new_size_too_small, L#log.name, CurSize}},
S);
Else ->
reply(From, Else, state_err(S, Else))
end;
not_ok ->
reply(From, {error, {badarg, size}}, S)
end;
L when L#log.status =:= {blocked, false} ->
reply(From, {error, {blocked_log, L#log.name}}, S);
L when L#log.blocked_by =:= From ->
reply(From, {error, {blocked_log, L#log.name}}, S);
_ ->
enqueue(Message, S)
end;
handle({From, inc_wrap_file}=Message, S) ->
case get(log) of
L when L#log.mode =:= read_only ->
reply(From, {error, {read_only_mode, L#log.name}}, S);
L when L#log.type =:= halt ->
reply(From, {error, {halt_log, L#log.name}}, S);
L when L#log.status =:= ok, S#state.cache_error =/= ok ->
loop(cache_error(S, [From]));
L when L#log.status =:= ok ->
case catch do_inc_wrap_file(L) of
{ok, L2, Lost} ->
put(log, L2),
notify_owners({wrap, Lost}),
reply(From, ok, S#state{cnt = S#state.cnt-Lost});
{error, Error, L2} ->
put(log, L2),
reply(From, Error, state_err(S, Error))
end;
L when L#log.status =:= {blocked, false} ->
reply(From, {error, {blocked_log, L#log.name}}, S);
L when L#log.blocked_by =:= From ->
reply(From, {error, {blocked_log, L#log.name}}, S);
_ ->
enqueue(Message, S)
end;
handle({From, {reopen, NewFile, Head, F, A}}, S) ->
case get(log) of
L when L#log.mode =:= read_only ->
reply(From, {error, {read_only_mode, L#log.name}}, S);
L when L#log.status =:= ok, S#state.cache_error =/= ok ->
loop(cache_error(S, [From]));
L when L#log.status =:= ok, L#log.filename =/= NewFile ->
case catch close_disk_log2(L) of
closed ->
File = L#log.filename,
case catch rename_file(File, NewFile, L#log.type) of
ok ->
H = merge_head(Head, L#log.head),
case do_open((S#state.args)#arg{name = L#log.name,
repair = truncate,
head = H,
file = File}) of
{ok, Res, L2, Cnt} ->
put(log, L2#log{owners = L#log.owners,
head = L#log.head,
users = L#log.users}),
notify_owners({truncated, S#state.cnt}),
erase(is_full),
case Res of
{error, _} ->
do_exit(S, From, Res,
?failure(Res, F, A));
_ ->
reply(From, ok, S#state{cnt = Cnt})
end;
Res ->
do_exit(S, From, Res, ?failure(Res, F, A))
end;
Error ->
do_exit(S, From, Error, ?failure(Error, reopen, 2))
end;
Error ->
do_exit(S, From, Error, ?failure(Error, F, A))
end;
L when L#log.status =:= ok ->
reply(From, {error, {same_file_name, L#log.name}}, S);
L ->
reply(From, {error, {blocked_log, L#log.name}}, S)
end;
handle({Server, {internal_open, A}}, S) ->
case get(log) of
undefined ->
case do_open(A) of % does the put
{ok, Res, L, Cnt} ->
put(log, opening_pid(A#arg.linkto, A#arg.notify, L)),
reply(Server, Res, S#state{args=A, cnt=Cnt});
Res ->
do_fast_exit(S, Server, Res)
end;
L ->
TestH = mk_head(A#arg.head, A#arg.format),
case compare_arg(A#arg.options, S#state.args, TestH, L#log.head) of
ok ->
case add_pid(A#arg.linkto, A#arg.notify, L) of
{ok, L1} ->
put(log, L1),
reply(Server, {ok, L#log.name}, S);
Error ->
reply(Server, Error, S)
end;
Error ->
reply(Server, Error, S)
end
end;
handle({From, close}, S) ->
case do_close(From, S) of
{stop, S1} ->
do_exit(S1, From, ok, normal);
{continue, S1} ->
reply(From, ok, S1)
end;
handle({From, info}, S) ->
reply(From, do_info(get(log), S#state.cnt), S);
handle({'EXIT', From, Reason}, S) when From =:= S#state.parent ->
%% Parent orders shutdown.
_ = do_stop(S),
exit(Reason);
handle({'EXIT', From, Reason}, S) when From =:= S#state.server ->
%% The server is gone.
_ = do_stop(S),
exit(Reason);
handle({'EXIT', From, _Reason}, S) ->
L = get(log),
case is_owner(From, L) of
{true, _Notify} ->
case close_owner(From, L, S) of
{stop, S1} ->
_ = do_stop(S1),
exit(normal);
{continue, S1} ->
loop(S1)
end;
false ->
%% 'users' is not decremented.
S1 = do_unblock(From, get(log), S),
loop(S1)
end;
handle({system, From, Req}, S) ->
sys:handle_system_msg(Req, From, S#state.parent, ?MODULE, [], S);
handle(_, S) ->
loop(S).
enqueue(Message, S) ->
loop(S#state{queue = [Message | S#state.queue]}).
%% Collect further log and sync requests already in the mailbox or queued
-define(MAX_LOOK_AHEAD, 64*1024).
log_loop(S, Pids, Bins, Sync) ->
log_loop(S, Pids, Bins, Sync, iolist_size(Bins), (get(log))#log.format).
%% Inlined.
log_loop(#state{cache_error = CE}=S, Pids, _Bins, _Sync, _Sz, _F) when CE =/= ok ->
loop(cache_error(S, Pids));
log_loop(#state{}=S, Pids, Bins, Sync, Sz, _F) when Sz > ?MAX_LOOK_AHEAD ->
loop(log_end(S, Pids, Bins, Sync));
log_loop(#state{messages = []}=S, Pids, Bins, Sync, Sz, F) ->
receive
Message ->
log_loop(Message, Pids, Bins, Sync, Sz, F, S)
after 0 ->
loop(log_end(S, Pids, Bins, Sync))
end;
log_loop(#state{messages = [M | Ms]}=S, Pids, Bins, Sync, Sz, F) ->
S1 = S#state{messages = Ms},
log_loop(M, Pids, Bins, Sync, Sz, F, S1).
%% Items logged after the last sync request found are sync:ed as well.
log_loop({alog,B}, Pids, Bins, Sync, Sz, internal=F, S) ->
%% {alog, _} allowed for the internal format only.
log_loop(S, Pids, [B | Bins], Sync, Sz+iolist_size(B), F);
log_loop({balog, B}, Pids, Bins, Sync, Sz, F, S) ->
log_loop(S, Pids, [B | Bins], Sync, Sz+iolist_size(B), F);
log_loop({From, {log, B}}, Pids, Bins, Sync, Sz, internal=F, S) ->
%% {log, _} allowed for the internal format only.
log_loop(S, [From | Pids], [B | Bins], Sync, Sz+iolist_size(B), F);
log_loop({From, {blog, B}}, Pids, Bins, Sync, Sz, F, S) ->
log_loop(S, [From | Pids], [B | Bins], Sync, Sz+iolist_size(B), F);
log_loop({From, sync}, Pids, Bins, Sync, Sz, F, S) ->
log_loop(S, Pids, Bins, [From | Sync], Sz, F);
log_loop(Message, Pids, Bins, Sync, _Sz, _F, S) ->
NS = log_end(S, Pids, Bins, Sync),
handle(Message, NS).
log_end(S, [], [], Sync) ->
log_end_sync(S, Sync);
log_end(S, Pids, Bins, Sync) ->
case do_log(get(log), rflat(Bins)) of
N when is_integer(N) ->
ok = replies(Pids, ok),
S1 = (state_ok(S))#state{cnt = S#state.cnt+N},
log_end_sync(S1, Sync);
{error, {error, {full, _Name}}, N} when Pids =:= [] ->
log_end_sync(state_ok(S#state{cnt = S#state.cnt + N}), Sync);
{error, Error, N} ->
ok = replies(Pids, Error),
state_err(S#state{cnt = S#state.cnt + N}, Error)
end.
%% Inlined.
log_end_sync(S, []) ->
S;
log_end_sync(S, Sync) ->
Res = do_sync(get(log)),
ok = replies(Sync, Res),
state_err(S, Res).
%% Inlined.
rflat([B]=L) when is_binary(B) -> L;
rflat([B]) -> B;
rflat(B) -> rflat(B, []).
rflat([B | Bs], L) when is_binary(B) ->
rflat(Bs, [B | L]);
rflat([B | Bs], L) ->
rflat(Bs, B ++ L);
rflat([], L) -> L.
%% -> {ok, Log} | {error, Error}
do_change_notify(L, Pid, Notify) ->
case is_owner(Pid, L) of
{true, Notify} ->
{ok, L};
{true, _OldNotify} when Notify =/= true, Notify =/= false ->
{error, {badarg, notify}};
{true, _OldNotify} ->
Owners = lists:keydelete(Pid, 1, L#log.owners),
L1 = L#log{owners = [{Pid, Notify} | Owners]},
{ok, L1};
false ->
{error, {not_owner, Pid}}
end.
%% -> {stop, S} | {continue, S}
do_close(Pid, S) ->
L = get(log),
case is_owner(Pid, L) of
{true, _Notify} ->
close_owner(Pid, L, S);
false ->
close_user(Pid, L, S)
end.
%% -> {stop, S} | {continue, S}
close_owner(Pid, L, S) ->
L1 = L#log{owners = lists:keydelete(Pid, 1, L#log.owners)},
put(log, L1),
S2 = do_unblock(Pid, get(log), S),
unlink(Pid),
do_close2(L1, S2).
%% -> {stop, S} | {continue, S}
close_user(Pid, L, S) when L#log.users > 0 ->
L1 = L#log{users = L#log.users - 1},
put(log, L1),
S2 = do_unblock(Pid, get(log), S),
do_close2(L1, S2);
close_user(_Pid, _L, S) ->
{continue, S}.
do_close2(L, S) when L#log.users =:= 0, L#log.owners =:= [] ->
{stop, S};
do_close2(_L, S) ->
{continue, S}.
%%-----------------------------------------------------------------
%% Callback functions for system messages handling.
%%-----------------------------------------------------------------
system_continue(_Parent, _, State) ->
loop(State).
-spec system_terminate(_, _, _, #state{}) -> no_return().
system_terminate(Reason, _Parent, _, State) ->
_ = do_stop(State),
exit(Reason).
%%-----------------------------------------------------------------
%% Temporay code for upgrade.
%%-----------------------------------------------------------------
system_code_change(State, _Module, _OldVsn, _Extra) ->
{ok, State}.
%%%----------------------------------------------------------------------
%%% Internal functions
%%%----------------------------------------------------------------------
-spec do_exit(#state{}, pid(), _, _) -> no_return().
do_exit(S, From, Message0, Reason) ->
R = do_stop(S),
Message = case S#state.cache_error of
Err when Err =/= ok -> Err;
_ when R =:= closed -> Message0;
_ when Message0 =:= ok -> R;
_ -> Message0
end,
_ = disk_log_server:close(self()),
ok = replies(From, Message),
?PROFILE(ep:done()),
exit(Reason).
-spec do_fast_exit(#state{}, pid(), _) -> no_return().
do_fast_exit(S, Server, Message) ->
_ = do_stop(S),
Server ! {disk_log, self(), Message},
exit(normal).
%% -> closed | Error
do_stop(S) ->
proc_q(S#state.queue ++ S#state.messages),
close_disk_log(get(log)).
proc_q([{From, _R}|Tail]) when is_pid(From) ->
From ! {disk_log, self(), {error, disk_log_stopped}},
proc_q(Tail);
proc_q([_|T]) -> %% async stuff
proc_q(T);
proc_q([]) ->
ok.
%% -> log()
opening_pid(Pid, Notify, L) ->
{ok, L1} = add_pid(Pid, Notify, L),
L1.
%% -> {ok, log()} | Error
add_pid(Pid, Notify, L) when is_pid(Pid) ->
case is_owner(Pid, L) of
false ->
link(Pid),
{ok, L#log{owners = [{Pid, Notify} | L#log.owners]}};
{true, Notify} ->
%% {error, {pid_already_connected, L#log.name}};
{ok, L};
{true, CurNotify} when Notify =/= CurNotify ->
{error, {arg_mismatch, notify, CurNotify, Notify}}
end;
add_pid(_NotAPid, _Notify, L) ->
{ok, L#log{users = L#log.users + 1}}.
unblock_pid(L) when L#log.blocked_by =:= none ->
ok;
unblock_pid(L) ->
case is_owner(L#log.blocked_by, L) of
{true, _Notify} ->
ok;
false ->
unlink(L#log.blocked_by)
end.
%% -> true | false
is_owner(Pid, L) ->
case lists:keysearch(Pid, 1, L#log.owners) of
{value, {_Pid, Notify}} ->
{true, Notify};
false ->
false
end.
%% ok | throw(Error)
rename_file(File, NewFile, halt) ->
case file:rename(File, NewFile) of
ok ->
ok;
Else ->
file_error(NewFile, Else)
end;
rename_file(File, NewFile, wrap) ->
rename_file(wrap_file_extensions(File), File, NewFile, ok).
rename_file([Ext|Exts], File, NewFile0, Res) ->
NewFile = add_ext(NewFile0, Ext),
NRes = case file:rename(add_ext(File, Ext), NewFile) of
ok ->
Res;
Else ->
file_error(NewFile, Else)
end,
rename_file(Exts, File, NewFile0, NRes);
rename_file([], _File, _NewFiles, Res) -> Res.
file_error(FileName, {error, Error}) ->
{error, {file_error, FileName, Error}}.
%% "Old" error messages have been kept, arg_mismatch has been added.
%%-spec compare_arg(dlog_options(), #arg{},
compare_arg([], _A, none, _OrigHead) ->
% no header option given
ok;
compare_arg([], _A, Head, OrigHead) when Head =/= OrigHead ->
{error, {arg_mismatch, head, OrigHead, Head}};
compare_arg([], _A, _Head, _OrigHead) ->
ok;
compare_arg([{Attr, Val} | Tail], A, Head, OrigHead) ->
case compare_arg(Attr, Val, A) of
{not_ok, OrigVal} ->
{error, {arg_mismatch, Attr, OrigVal, Val}};
ok ->
compare_arg(Tail, A, Head, OrigHead);
Error ->
Error
end.
-spec compare_arg(atom(), _, #arg{}) ->
'ok' | {'not_ok', _} | {'error', {atom(), _}}.
compare_arg(file, F, A) when F =/= A#arg.file ->
{error, {name_already_open, A#arg.name}};
compare_arg(mode, read_only, A) when A#arg.mode =:= read_write ->
{error, {open_read_write, A#arg.name}};
compare_arg(mode, read_write, A) when A#arg.mode =:= read_only ->
{error, {open_read_only, A#arg.name}};
compare_arg(type, T, A) when T =/= A#arg.type ->
{not_ok, A#arg.type};
compare_arg(format, F, A) when F =/= A#arg.format ->
{not_ok, A#arg.format};
compare_arg(repair, R, A) when R =/= A#arg.repair ->
%% not used, but check it anyway...
{not_ok, A#arg.repair};
compare_arg(_Attr, _Val, _A) ->
ok.
%% -> {ok, Res, log(), Cnt} | Error
do_open(A) ->
#arg{type = Type, format = Format, name = Name, head = Head0,
file = FName, repair = Repair, size = Size, mode = Mode,
version = V} = A,
Head = mk_head(Head0, Format),
case do_open2(Type, Format, Name, FName, Repair, Size, Mode, Head, V) of
{ok, Ret, Extra, FormatType, NoItems} ->
L = #log{name = Name, type = Type, format = Format,
filename = FName, size = Size,
format_type = FormatType, head = Head, mode = Mode,
version = V, extra = Extra},
{ok, Ret, L, NoItems};
Error ->
Error
end.
mk_head({head, Term}, internal) -> {ok, term_to_binary(Term)};
mk_head({head, Bytes}, external) -> {ok, ensure_binary(Bytes)};
mk_head(H, _) -> H.
terms2bins([T | Ts]) ->
[term_to_binary(T) | terms2bins(Ts)];
terms2bins([]) ->
[].
ensure_binary_list(Bs) ->
ensure_binary_list(Bs, Bs).
ensure_binary_list([B | Bs], Bs0) when is_binary(B) ->
ensure_binary_list(Bs, Bs0);
ensure_binary_list([], Bs0) ->
Bs0;
ensure_binary_list(_, Bs0) ->
make_binary_list(Bs0).
make_binary_list([B | Bs]) ->
[ensure_binary(B) | make_binary_list(Bs)];
make_binary_list([]) ->
[].
ensure_binary(Binary) when is_binary(Binary) ->
Binary;
ensure_binary(Bytes) ->
list_to_binary(Bytes).
%%-----------------------------------------------------------------
%% Change size of the logs in runtime.
%%-----------------------------------------------------------------
%% -> ok | {big, CurSize} | throw(Error)
do_change_size(L, NewSize) when L#log.type =:= halt ->
Halt = L#log.extra,
CurB = Halt#halt.curB,
NewLog = L#log{extra = Halt#halt{size = NewSize}},
if
NewSize =:= infinity ->
erase(is_full),
put(log, NewLog),
ok;
CurB =< NewSize ->
erase(is_full),
put(log, NewLog),
ok;
true ->
{big, CurB}
end;
do_change_size(L, NewSize) when L#log.type =:= wrap ->
#log{extra = Extra, version = Version} = L,
{ok, Handle} = disk_log_1:change_size_wrap(Extra, NewSize, Version),
erase(is_full),
put(log, L#log{extra = Handle}),
ok.
%% -> {ok, Head} | Error; Head = none | {head, H} | {M,F,A}
check_head({head, none}, _Format) ->
{ok, none};
check_head({head_func, {M, F, A}}, _Format) when is_atom(M),
is_atom(F),
is_list(A) ->
{ok, {M, F, A}};
check_head({head, Head}, external) ->
case catch ensure_binary(Head) of
{'EXIT', _} ->
{error, {badarg, head}};
_ ->
{ok, {head, Head}}
end;
check_head({head, Term}, internal) ->
{ok, {head, Term}};
check_head(_Head, _Format) ->
{error, {badarg, head}}.
check_size(wrap, {NewMaxB,NewMaxF}) when
is_integer(NewMaxB), is_integer(NewMaxF),
NewMaxB > 0, NewMaxB =< ?MAX_BYTES, NewMaxF > 0, NewMaxF < ?MAX_FILES ->
ok;
check_size(halt, NewSize) when is_integer(NewSize), NewSize > 0 ->
ok;
check_size(halt, infinity) ->
ok;
check_size(_, _) ->
not_ok.
%%-----------------------------------------------------------------
%% Increment a wrap log.
%%-----------------------------------------------------------------
%% -> {ok, log(), Lost} | {error, Error, log()}
do_inc_wrap_file(L) ->
#log{format = Format, extra = Handle} = L,
case Format of
internal ->
case disk_log_1:mf_int_inc(Handle, L#log.head) of
{ok, Handle2, Lost} ->
{ok, L#log{extra = Handle2}, Lost};
{error, Error, Handle2} ->
{error, Error, L#log{extra = Handle2}}
end;
external ->
case disk_log_1:mf_ext_inc(Handle, L#log.head) of
{ok, Handle2, Lost} ->
{ok, L#log{extra = Handle2}, Lost};
{error, Error, Handle2} ->
{error, Error, L#log{extra = Handle2}}
end
end.
%%-----------------------------------------------------------------
%% Open a log file.
%%-----------------------------------------------------------------
%% -> {ok, Reply, log(), Cnt} | Error
%% Note: the header is always written, even if the log size is too small.
do_open2(halt, internal, Name, FName, Repair, Size, Mode, Head, _V) ->
case catch disk_log_1:int_open(FName, Repair, Mode, Head) of
{ok, {_Alloc, FdC, {NoItems, _NoBytes}, FileSize}} ->
Halt = #halt{fdc = FdC, curB = FileSize, size = Size},
{ok, {ok, Name}, Halt, halt_int, NoItems};
{repaired, FdC, Rec, Bad, FileSize} ->
Halt = #halt{fdc = FdC, curB = FileSize, size = Size},
{ok, {repaired, Name, {recovered, Rec}, {badbytes, Bad}},
Halt, halt_int, Rec};
Error ->
Error
end;
do_open2(wrap, internal, Name, FName, Repair, Size, Mode, Head, V) ->
{MaxB, MaxF} = Size,
case catch
disk_log_1:mf_int_open(FName, MaxB, MaxF, Repair, Mode, Head, V) of
{ok, Handle, Cnt} ->
{ok, {ok, Name}, Handle, wrap_int, Cnt};
{repaired, Handle, Rec, Bad, Cnt} ->
{ok, {repaired, Name, {recovered, Rec}, {badbytes, Bad}},
Handle, wrap_int, Cnt};
Error ->
Error
end;
do_open2(halt, external, Name, FName, Repair, Size, Mode, Head, _V) ->
case catch disk_log_1:ext_open(FName, Repair, Mode, Head) of
{ok, {_Alloc, FdC, {NoItems, _NoBytes}, FileSize}} ->
Halt = #halt{fdc = FdC, curB = FileSize, size = Size},
{ok, {ok, Name}, Halt, halt_ext, NoItems};
Error ->
Error
end;
do_open2(wrap, external, Name, FName, Repair, Size, Mode, Head, V) ->
{MaxB, MaxF} = Size,
case catch
disk_log_1:mf_ext_open(FName, MaxB, MaxF, Repair, Mode, Head, V) of
{ok, Handle, Cnt} ->
{ok, {ok, Name}, Handle, wrap_ext, Cnt};
Error ->
Error
end.
%% -> closed | Error
close_disk_log(undefined) ->
closed;
close_disk_log(L) ->
unblock_pid(L),
F = fun({Pid, _}) ->
unlink(Pid)
end,
lists:foreach(F, L#log.owners),
R = (catch close_disk_log2(L)),
erase(log),
R.
-spec close_disk_log2(#log{}) -> 'closed'. % | throw(Error)
close_disk_log2(L) ->
case L of
#log{format_type = halt_int, mode = Mode, extra = Halt} ->
disk_log_1:close(Halt#halt.fdc, L#log.filename, Mode);
#log{format_type = wrap_int, mode = Mode, extra = Handle} ->
disk_log_1:mf_int_close(Handle, Mode);
#log{format_type = halt_ext, extra = Halt} ->
disk_log_1:fclose(Halt#halt.fdc, L#log.filename);
#log{format_type = wrap_ext, mode = Mode, extra = Handle} ->
disk_log_1:mf_ext_close(Handle, Mode)
end,
closed.
do_format_error({error, Module, Error}) ->
Module:format_error(Error);
do_format_error({error, Reason}) ->
do_format_error(Reason);
do_format_error({Node, Error = {error, _Reason}}) ->
lists:append(io_lib:format("~p: ", [Node]), do_format_error(Error));
do_format_error({badarg, Arg}) ->
io_lib:format("The argument ~p is missing, not recognized or "
"not wellformed~n", [Arg]);
do_format_error({size_mismatch, OldSize, ArgSize}) ->
io_lib:format("The given size ~p does not match the size ~p found on "
"the disk log size file~n", [ArgSize, OldSize]);
do_format_error({read_only_mode, Log}) ->
io_lib:format("The disk log ~tp has been opened read-only, but the "
"requested operation needs read-write access~n", [Log]);
do_format_error({format_external, Log}) ->
io_lib:format("The requested operation can only be applied on internally "
"formatted disk logs, but ~tp is externally formatted~n",
[Log]);
do_format_error({blocked_log, Log}) ->
io_lib:format("The blocked disk log ~tp does not queue requests, or "
"the log has been blocked by the calling process~n", [Log]);
do_format_error({full, Log}) ->
io_lib:format("The halt log ~tp is full~n", [Log]);
do_format_error({not_blocked, Log}) ->
io_lib:format("The disk log ~tp is not blocked~n", [Log]);
do_format_error({not_owner, Pid}) ->
io_lib:format("The pid ~tp is not an owner of the disk log~n", [Pid]);
do_format_error({not_blocked_by_pid, Log}) ->
io_lib:format("The disk log ~tp is blocked, but only the blocking pid "
"can unblock a disk log~n", [Log]);
do_format_error({new_size_too_small, Log, CurrentSize}) ->
io_lib:format("The current size ~p of the halt log ~tp is greater than the "
"requested new size~n", [CurrentSize, Log]);
do_format_error({halt_log, Log}) ->
io_lib:format("The halt log ~tp cannot be wrapped~n", [Log]);
do_format_error({same_file_name, Log}) ->
io_lib:format("Current and new file name of the disk log ~tp "
"are the same~n", [Log]);
do_format_error({arg_mismatch, Option, FirstValue, ArgValue}) ->
io_lib:format("The value ~tp of the disk log option ~p does not match "
"the current value ~tp~n", [ArgValue, Option, FirstValue]);
do_format_error({name_already_open, Log}) ->
io_lib:format("The disk log ~tp has already opened another file~n", [Log]);
do_format_error({node_already_open, Log}) ->
io_lib:format("The distribution option of the disk log ~tp does not match "
"already open log~n", [Log]);
do_format_error({open_read_write, Log}) ->
io_lib:format("The disk log ~tp has already been opened read-write~n",
[Log]);
do_format_error({open_read_only, Log}) ->
io_lib:format("The disk log ~tp has already been opened read-only~n",
[Log]);
do_format_error({not_internal_wrap, Log}) ->
io_lib:format("The requested operation cannot be applied since ~tp is not "
"an internally formatted disk log~n", [Log]);
do_format_error(no_such_log) ->
io_lib:format("There is no disk log with the given name~n", []);
do_format_error(nonode) ->
io_lib:format("There seems to be no node up that can handle "
"the request~n", []);
do_format_error(nodedown) ->
io_lib:format("There seems to be no node up that can handle "
"the request~n", []);
do_format_error({corrupt_log_file, FileName}) ->
io_lib:format("The disk log file \"~ts\" contains corrupt data~n",
[FileName]);
do_format_error({need_repair, FileName}) ->
io_lib:format("The disk log file \"~ts\" has not been closed properly and "
"needs repair~n", [FileName]);
do_format_error({not_a_log_file, FileName}) ->
io_lib:format("The file \"~ts\" is not a wrap log file~n", [FileName]);
do_format_error({invalid_header, InvalidHeader}) ->
io_lib:format("The disk log header is not wellformed: ~p~n",
[InvalidHeader]);
do_format_error(end_of_log) ->
io_lib:format("An attempt was made to step outside a not yet "
"full wrap log~n", []);
do_format_error({invalid_index_file, FileName}) ->
io_lib:format("The wrap log index file \"~ts\" cannot be used~n",
[FileName]);
do_format_error({no_continuation, BadCont}) ->
io_lib:format("The term ~p is not a chunk continuation~n", [BadCont]);
do_format_error({file_error, FileName, Reason}) ->
io_lib:format("\"~ts\": ~tp~n", [FileName, file:format_error(Reason)]);
do_format_error(E) ->
io_lib:format("~tp~n", [E]).
do_info(L, Cnt) ->
#log{name = Name, type = Type, mode = Mode, filename = File,
extra = Extra, status = Status, owners = Owners, users = Users,
format = Format, head = Head} = L,
Size = case Type of
wrap ->
disk_log_1:get_wrap_size(Extra);
halt ->
Extra#halt.size
end,
Distribution =
case disk_log_server:get_log_pids(Name) of
{local, _Pid} ->
local;
{distributed, Pids} ->
[node(P) || P <- Pids];
undefined -> % "cannot happen"
[]
end,
RW = case Type of
wrap when Mode =:= read_write ->
#handle{curB = CurB, curF = CurF,
cur_cnt = CurCnt, acc_cnt = AccCnt,
noFull = NoFull, accFull = AccFull} = Extra,
NewAccFull = AccFull + NoFull,
NewExtra = Extra#handle{noFull = 0, accFull = NewAccFull},
put(log, L#log{extra = NewExtra}),
[{no_current_bytes, CurB},
{no_current_items, CurCnt},
{no_items, Cnt},
{no_written_items, CurCnt + AccCnt},
{current_file, CurF},
{no_overflows, {NewAccFull, NoFull}}
];
halt when Mode =:= read_write ->
IsFull = case get(is_full) of
undefined -> false;
_ -> true
end,
[{full, IsFull},
{no_written_items, Cnt}
];
_ when Mode =:= read_only ->
[]
end,
HeadL = case Mode of
read_write ->
[{head, Head}];
read_only ->
[]
end,
Common = [{name, Name},
{file, File},
{type, Type},
{format, Format},
{size, Size},
{items, Cnt}, % kept for "backward compatibility" (undocumented)
{owners, Owners},
{users, Users}] ++
HeadL ++
[{mode, Mode},
{status, Status},
{node, node()},
{distributed, Distribution}
],
Common ++ RW.
do_block(Pid, QueueLogRecs, L) ->
L2 = L#log{status = {blocked, QueueLogRecs}, blocked_by = Pid},
put(log, L2),
case is_owner(Pid, L2) of
{true, _Notify} ->
ok;
false ->
link(Pid)
end.
do_unblock(Pid, L, S) when L#log.blocked_by =:= Pid ->
do_unblock(L, S);
do_unblock(_Pid, _L, S) ->
S.
do_unblock(L, S) ->
unblock_pid(L),
L2 = L#log{blocked_by = none, status = ok},
put(log, L2),
%% Since the block request is synchronous, and the blocking
%% process is the only process that can unblock, all requests in
%% 'messages' will have been put in 'queue' before the unblock
%% request is granted.
[] = S#state.messages, % assertion
S#state{queue = [], messages = lists:reverse(S#state.queue)}.
-spec do_log(#log{}, [binary()]) -> integer() | {'error', _, integer()}.
do_log(L, B) when L#log.type =:= halt ->
#log{format = Format, extra = Halt} = L,
#halt{curB = CurSize, size = Sz} = Halt,
{Bs, BSize} = logl(B, Format),
case get(is_full) of
true ->
{error, {error, {full, L#log.name}}, 0};
undefined when Sz =:= infinity; CurSize + BSize =< Sz ->
halt_write(Halt, L, B, Bs, BSize);
undefined ->
halt_write_full(L, B, Format, 0)
end;
do_log(L, B) when L#log.format_type =:= wrap_int ->
case disk_log_1:mf_int_log(L#log.extra, B, L#log.head) of
{ok, Handle, Logged, Lost, Wraps} ->
notify_owners_wrap(Wraps),
put(log, L#log{extra = Handle}),
Logged - Lost;
{ok, Handle, Logged} ->
put(log, L#log{extra = Handle}),
Logged;
{error, Error, Handle, Logged, Lost} ->
put(log, L#log{extra = Handle}),
{error, Error, Logged - Lost}
end;
do_log(L, B) when L#log.format_type =:= wrap_ext ->
case disk_log_1:mf_ext_log(L#log.extra, B, L#log.head) of
{ok, Handle, Logged, Lost, Wraps} ->
notify_owners_wrap(Wraps),
put(log, L#log{extra = Handle}),
Logged - Lost;
{ok, Handle, Logged} ->
put(log, L#log{extra = Handle}),
Logged;
{error, Error, Handle, Logged, Lost} ->
put(log, L#log{extra = Handle}),
{error, Error, Logged - Lost}
end.
logl(B, external) ->
{B, iolist_size(B)};
logl(B, internal) ->
disk_log_1:logl(B).
halt_write_full(L, [Bin | Bins], Format, N) ->
B = [Bin],
{Bs, BSize} = logl(B, Format),
Halt = L#log.extra,
#halt{curB = CurSize, size = Sz} = Halt,
if
CurSize + BSize =< Sz ->
case halt_write(Halt, L, B, Bs, BSize) of
N1 when is_integer(N1) ->
halt_write_full(get(log), Bins, Format, N+N1);
Error ->
Error
end;
true ->
halt_write_full(L, [], Format, N)
end;
halt_write_full(L, _Bs, _Format, N) ->
put(is_full, true),
notify_owners(full),
{error, {error, {full, L#log.name}}, N}.
halt_write(Halt, L, B, Bs, BSize) ->
case disk_log_1:fwrite(Halt#halt.fdc, L#log.filename, Bs, BSize) of
{ok, NewFdC} ->
NCurB = Halt#halt.curB + BSize,
NewHalt = Halt#halt{fdc = NewFdC, curB = NCurB},
put(log, L#log{extra = NewHalt}),
length(B);
{Error, NewFdC} ->
put(log, L#log{extra = Halt#halt{fdc = NewFdC}}),
{error, Error, 0}
end.
%% -> ok | Error
do_write_cache(#log{filename = FName, type = halt, extra = Halt} = Log) ->
{Reply, NewFdC} = disk_log_1:write_cache(Halt#halt.fdc, FName),
put(log, Log#log{extra = Halt#halt{fdc = NewFdC}}),
Reply;
do_write_cache(#log{type = wrap, extra = Handle} = Log) ->
{Reply, NewHandle} = disk_log_1:mf_write_cache(Handle),
put(log, Log#log{extra = NewHandle}),
Reply.
%% -> ok | Error
do_sync(#log{filename = FName, type = halt, extra = Halt} = Log) ->
{Reply, NewFdC} = disk_log_1:sync(Halt#halt.fdc, FName),
put(log, Log#log{extra = Halt#halt{fdc = NewFdC}}),
Reply;
do_sync(#log{type = wrap, extra = Handle} = Log) ->
{Reply, NewHandle} = disk_log_1:mf_sync(Handle),
put(log, Log#log{extra = NewHandle}),
Reply.
%% -> ok | Error | throw(Error)
do_trunc(L, Head) when L#log.type =:= halt ->
#log{filename = FName, extra = Halt} = L,
FdC = Halt#halt.fdc,
{Reply1, FdC2} =
case L#log.format of
internal ->
disk_log_1:truncate(FdC, FName, Head);
external ->
case disk_log_1:truncate_at(FdC, FName, bof) of
{ok, NFdC} when Head =:= none ->
{ok, NFdC};
{ok, NFdC} ->
{ok, H} = Head,
disk_log_1:fwrite(NFdC, FName, H, byte_size(H));
R ->
R
end
end,
{Reply, NewHalt} =
case disk_log_1:position(FdC2, FName, cur) of
{ok, NewFdC, FileSize} when Reply1 =:= ok ->
{ok, Halt#halt{fdc = NewFdC, curB = FileSize}};
{Reply2, NewFdC} ->
{Reply2, Halt#halt{fdc = NewFdC}};
{ok, NewFdC, _} ->
{Reply1, Halt#halt{fdc = NewFdC}}
end,
put(log, L#log{extra = NewHalt}),
Reply;
do_trunc(L, Head) when L#log.type =:= wrap ->
Handle = L#log.extra,
OldHead = L#log.head,
{MaxB, MaxF} = disk_log_1:get_wrap_size(Handle),
ok = do_change_size(L, {MaxB, 1}),
NewLog = trunc_wrap((get(log))#log{head = Head}),
%% Just to remove all files with suffix > 1:
NewLog2 = trunc_wrap(NewLog),
NewHandle = (NewLog2#log.extra)#handle{noFull = 0, accFull = 0},
do_change_size(NewLog2#log{extra = NewHandle, head = OldHead},
{MaxB, MaxF}).
trunc_wrap(L) ->
case do_inc_wrap_file(L) of
{ok, L2, _Lost} ->
L2;
{error, Error, _L2} ->
throw(Error)
end.
do_chunk(#log{format_type = halt_int, extra = Halt} = L, Pos, B, N) ->
FdC = Halt#halt.fdc,
{NewFdC, Reply} =
case L#log.mode of
read_only ->
disk_log_1:chunk_read_only(FdC, L#log.filename, Pos, B, N);
read_write ->
disk_log_1:chunk(FdC, L#log.filename, Pos, B, N)
end,
put(log, L#log{extra = Halt#halt{fdc = NewFdC}}),
Reply;
do_chunk(#log{format_type = wrap_int, mode = read_only,
extra = Handle} = Log, Pos, B, N) ->
{NewHandle, Reply} = disk_log_1:mf_int_chunk_read_only(Handle, Pos, B, N),
put(log, Log#log{extra = NewHandle}),
Reply;
do_chunk(#log{format_type = wrap_int, extra = Handle} = Log, Pos, B, N) ->
{NewHandle, Reply} = disk_log_1:mf_int_chunk(Handle, Pos, B, N),
put(log, Log#log{extra = NewHandle}),
Reply;
do_chunk(Log, _Pos, _B, _) ->
{error, {format_external, Log#log.name}}.
do_chunk_step(#log{format_type = wrap_int, extra = Handle}, Pos, N) ->
disk_log_1:mf_int_chunk_step(Handle, Pos, N);
do_chunk_step(Log, _Pos, _N) ->
{error, {not_internal_wrap, Log#log.name}}.
%% Inlined.
replies(Pids, Reply) ->
M = {disk_log, self(), Reply},
send_reply(Pids, M).
send_reply(Pid, M) when is_pid(Pid) ->
Pid ! M,
ok;
send_reply([Pid | Pids], M) ->
Pid ! M,
send_reply(Pids, M);
send_reply([], _M) ->
ok.
reply(To, Reply, S) ->
To ! {disk_log, self(), Reply},
loop(S).
req(Log, R) ->
case disk_log_server:get_log_pids(Log) of
{local, Pid} ->
monitor_request(Pid, R);
undefined ->
{error, no_such_log};
{distributed, Pids} ->
multi_req({self(), R}, Pids)
end.
multi_req(Msg, Pids) ->
Refs =
lists:map(fun(Pid) ->
Ref = erlang:monitor(process, Pid),
Pid ! Msg,
{Pid, Ref}
end, Pids),
lists:foldl(fun({Pid, Ref}, Reply) ->
receive
{'DOWN', Ref, process, Pid, _Info} ->
Reply;
{disk_log, Pid, _Reply} ->
erlang:demonitor(Ref, [flush]),
ok
end
end, {error, nonode}, Refs).
sreq(Log, R) ->
case nearby_pid(Log, node()) of
undefined ->
{error, no_such_log};
Pid ->
monitor_request(Pid, R)
end.
%% Local req - always talk to log on Node
lreq(Log, R, Node) ->
case nearby_pid(Log, Node) of
Pid when is_pid(Pid), node(Pid) =:= Node ->
monitor_request(Pid, R);
_Else ->
{error, no_such_log}
end.
nearby_pid(Log, Node) ->
case disk_log_server:get_log_pids(Log) of
undefined ->
undefined;
{local, Pid} ->
Pid;
{distributed, Pids} ->
get_near_pid(Pids, Node)
end.
-spec get_near_pid([pid(),...], node()) -> pid().
get_near_pid([Pid | _], Node) when node(Pid) =:= Node -> Pid;
get_near_pid([Pid], _ ) -> Pid;
get_near_pid([_ | T], Node) -> get_near_pid(T, Node).
monitor_request(Pid, Req) ->
Ref = erlang:monitor(process, Pid),
Pid ! {self(), Req},
receive
{'DOWN', Ref, process, Pid, _Info} ->
{error, no_such_log};
{disk_log, Pid, Reply} when not is_tuple(Reply) orelse
element(2, Reply) =/= disk_log_stopped ->
erlang:demonitor(Ref, [flush]),
Reply
end.
req2(Pid, R) ->
monitor_request(Pid, R).
merge_head(none, Head) ->
Head;
merge_head(Head, _) ->
Head.
%% -> List of extensions of existing files (no dot included) | throw(FileError)
wrap_file_extensions(File) ->
{_CurF, _CurFSz, _TotSz, NoOfFiles} =
disk_log_1:read_index_file(File),
Fs = if
NoOfFiles >= 1 ->
lists:seq(1, NoOfFiles);
NoOfFiles =:= 0 ->
[]
end,
Fun = fun(Ext) ->
case file:read_file_info(add_ext(File, Ext)) of
{ok, _} ->
true;
_Else ->
false
end
end,
lists:filter(Fun, ["idx", "siz" | Fs]).
add_ext(File, Ext) ->
lists:concat([File, ".", Ext]).
notify(Log, R) ->
case disk_log_server:get_log_pids(Log) of
undefined ->
{error, no_such_log};
{local, Pid} ->
Pid ! R,
ok;
{distributed, Pids} ->
lists:foreach(fun(Pid) -> Pid ! R end, Pids),
ok
end.
notify_owners_wrap([]) ->
ok;
notify_owners_wrap([N | Wraps]) ->
notify_owners({wrap, N}),
notify_owners_wrap(Wraps).
notify_owners(Note) ->
L = get(log),
Msg = {disk_log, node(), L#log.name, Note},
lists:foreach(fun({Pid, true}) -> Pid ! Msg;
(_) -> ok
end, L#log.owners).
cache_error(S, Pids) ->
Error = S#state.cache_error,
ok = replies(Pids, Error),
state_err(S#state{cache_error = ok}, Error).
state_ok(S) ->
state_err(S, ok).
-spec state_err(#state{}, dlog_state_error()) -> #state{}.
state_err(S, Err) when S#state.error_status =:= Err -> S;
state_err(S, Err) ->
notify_owners({error_status, Err}),
S#state{error_status = Err}.
