%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1997-2017. 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%
%%
-define(DISK_LOG_NAME_TABLE, disk_log_names).
-define(DISK_LOG_PID_TABLE, disk_log_pids).
%% File format version
-define(VERSION, 2).
%% HEADSZ is the size of the file header,
%% HEADERSZ is the size of the item header ( = ?SIZESZ + ?MAGICSZ).
-define(HEADSZ, 8).
-define(SIZESZ, 4).
-define(MAGICSZ, 4).
-define(HEADERSZ, 8).
-define(MAGICHEAD, <<12,33,44,55>>).
-define(MAGICINT, 203500599). %% ?MAGICHEAD = <<?MAGICINT:32>>
-define(BIGMAGICHEAD, <<98,87,76,65>>).
-define(BIGMAGICINT, 1649888321). %% ?BIGMAGICHEAD = <<?BIGMAGICINT:32>>
-define(MIN_MD5_TERM, 65528).% (?MAX_CHUNK_SIZE - ?HEADERSZ)
-define(MAX_FILES, 65000).
-define(MAX_BYTES, ((1 bsl 64) - 1)).
-define(MAX_CHUNK_SIZE, 65536).
-define(MAX_FWRITE_CACHE, 65536).
%% Object defines
-define(LOGMAGIC, <<1,2,3,4>>).
-define(OPENED, <<6,7,8,9>>).
-define(CLOSED, <<99,88,77,11>>).
%% Needed for the definition of #file_info{}
%% Must use include_lib() so that we always can be sure to find
%% file.hrl. A relative path will not work in an installed system.
-include_lib("kernel/include/file.hrl").
%%------------------------------------------------------------------------
%% Types -- alphabetically
%%------------------------------------------------------------------------
-type dlog_format() :: 'external' | 'internal'.
-type dlog_format_type() :: 'halt_ext' | 'halt_int' | 'wrap_ext' | 'wrap_int'.
-type dlog_head() :: 'none' | {'ok', binary()} | mfa().
-type dlog_head_opt() :: none | term() | iodata().
-type log() :: term(). % XXX: refine
-type dlog_mode() :: 'read_only' | 'read_write'.
-type dlog_name() :: atom() | string().
-type dlog_optattr() :: 'name' | 'file' | 'linkto' | 'repair' | 'type'
| 'format' | 'size' | 'distributed' | 'notify'
| 'head' | 'head_func' | 'mode'.
-type dlog_option() :: {name, Log :: log()}
| {file, FileName :: file:filename()}
| {linkto, LinkTo :: none | pid()}
| {repair, Repair :: true | false | truncate}
| {type, Type :: dlog_type()}
| {format, Format :: dlog_format()}
| {size, Size :: dlog_size()}
| {distributed, Nodes :: [node()]}
| {notify, boolean()}
| {head, Head :: dlog_head_opt()}
| {head_func, MFA :: {atom(), atom(), list()}}
| {mode, Mode :: dlog_mode()}.
-type dlog_options() :: [dlog_option()].
-type dlog_repair() :: 'truncate' | boolean().
-type dlog_size() :: 'infinity' | pos_integer()
| {MaxNoBytes :: pos_integer(),
MaxNoFiles :: pos_integer()}.
-type dlog_status() :: 'ok' | {'blocked', 'false' | [_]}. %QueueLogRecords
-type dlog_type() :: 'halt' | 'wrap'.
%%------------------------------------------------------------------------
%% Records
%%------------------------------------------------------------------------
%% record of args for open
-record(arg, {name = 0,
version = undefined,
file = none :: 'none' | file:filename(),
repair = true :: dlog_repair(),
size = infinity :: dlog_size(),
type = halt :: dlog_type(),
distributed = false :: 'false' | {'true', [node()]},
format = internal :: dlog_format(),
linkto = self() :: 'none' | pid(),
head = none,
mode = read_write :: dlog_mode(),
notify = false :: boolean(),
options = [] :: dlog_options()}).
-record(cache, %% Cache for logged terms (per file descriptor).
{fd :: file:fd(), %% File descriptor.
sz = 0 :: non_neg_integer(), %% Number of bytes in the cache.
c = [] :: iodata()} %% The cache.
).
-record(halt, %% For a halt log.
{fdc :: #cache{}, %% A cache record.
curB :: non_neg_integer(), %% Number of bytes on the file.
size :: dlog_size()}
).
-record(handle, %% For a wrap log.
{filename :: file:filename(), %% Same as log.filename
maxB :: pos_integer(), %% Max size of the files.
maxF :: pos_integer() | {pos_integer(),pos_integer()},
%% When pos_integer(), maximum number of files.
%% The form {NewMaxF, OldMaxF} is used when the
%% number of wrap logs are decreased. The files
%% are not removed when the size is changed but
%% next time the files are to be used, i.e next
%% time the wrap log has filled the
%% Dir/Name.NewMaxF file.
curB :: non_neg_integer(), %% Number of bytes on current file.
curF :: integer(), %% Current file number.
cur_fdc :: #cache{}, %% Current file descriptor.
cur_name :: file:filename(), %% Current file name for error reports.
cur_cnt :: non_neg_integer(), %% Number of items on current file,
%% header inclusive.
acc_cnt :: non_neg_integer(), %% acc_cnt+cur_cnt is number of items
%% written since the log was opened.
firstPos :: non_neg_integer(), %% Start position for first item
%% (after header).
noFull :: non_neg_integer(), %% Number of overflows since last
%% use of info/1 on this log, or
%% since log was opened if info/1
%% has not yet been used on this log.
accFull :: non_neg_integer()} %% noFull+accFull is number of
%% oveflows since the log was opened.
).
-record(log,
{status = ok :: dlog_status(),
name :: dlog_name(), %% the key leading to this structure
blocked_by = none :: 'none' | pid(), %% pid of blocker
users = 0 :: non_neg_integer(), %% non-linked users
filename :: file:filename(), %% real name of the file
owners = [] :: [{pid(), boolean()}],%% [{pid, notify}]
type :: dlog_type(),
format :: dlog_format(),
format_type :: dlog_format_type(),
head = none, %% none | {head, H} | {M,F,A}
%% called when wraplog wraps
mode :: dlog_mode(),
size, %% value of open/1 option 'size' (never changed)
extra :: #halt{} | #handle{}, %% type of the log
version :: integer()} %% if wrap log file
).
-record(continuation, %% Chunk continuation.
{pid = self() :: pid(),
pos :: non_neg_integer() | {integer(), non_neg_integer()},
b :: binary() | [] | pos_integer()}
).
-type dlog_cont() :: 'start' | #continuation{}.
