%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2010. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
-module(dets).
%% Disk based linear hashing lookup dictionary.
%% Public.
-export([all/0,
bchunk/2,
close/1,
delete/2,
delete_all_objects/1,
delete_object/2,
first/1,
foldl/3,
foldr/3,
from_ets/2,
info/1,
info/2,
init_table/2,
init_table/3,
insert/2,
insert_new/2,
is_compatible_bchunk_format/2,
is_dets_file/1,
lookup/2,
match/1,
match/2,
match/3,
match_delete/2,
match_object/1,
match_object/2,
match_object/3,
member/2,
next/2,
open_file/1,
open_file/2,
pid2name/1,
repair_continuation/2,
safe_fixtable/2,
select/1,
select/2,
select/3,
select_delete/2,
slot/2,
sync/1,
table/1,
table/2,
to_ets/2,
traverse/2,
update_counter/3]).
%% Server export.
-export([start/0, stop/0]).
%% Internal exports.
-export([istart_link/1, init/2, internal_open/3, add_user/3,
internal_close/1, remove_user/2,
system_continue/3, system_terminate/4, system_code_change/4]).
%% Debug.
-export([file_info/1,
fsck/1,
fsck/2,
get_head_field/2,
view/1,
where/2,
verbose/0,
verbose/1
]).
%% Not documented, or not ready for publication.
-export([lookup_keys/2]).
-export_type([tab_name/0]).
-compile({inline, [{einval,2},{badarg,2},{undefined,1},
{badarg_exit,2},{lookup_reply,2}]}).
-include_lib("kernel/include/file.hrl").
-include("dets.hrl").
-type object() :: tuple().
-type pattern() :: atom() | tuple().
-type tab_name() :: atom() | reference().
%%% This is the implementation of the mnesia file storage. Each (non
%%% ram-copy) table is maintained in a corresponding .DAT file. The
%%% dat file is organized as a segmented linear hashlist. The head of
%%% the file with the split indicator, size etc is held in ram by the
%%% server at all times.
%%%
%%% The parts specific for formats up to and including 8(c) are
%%% implemented in dets_v8.erl, parts specific for format 9 are
%%% implemented in dets_v9.erl.
%% The method of hashing is the so called linear hashing algorithm
%% with segments.
%%
%% Linear hashing:
%%
%% - n indicates next bucket to split (initially zero);
%% - m is the size of the hash table
%% - initially next = m and n = 0
%%
%% - to insert:
%% - hash = key mod m
%% - if hash < n then hash = key mod 2m
%% - when the number of objects exceeds the initial size
%% of the hash table, each insertion of an object
%% causes bucket n to be split:
%% - add a new bucket to the end of the table
%% - redistribute the contents of bucket n
%% using hash = key mod 2m
%% - increment n
%% - if n = m then m = 2m, n = 0
%% - to search:
%% hash = key mod m
%% if hash < n then hash = key mod 2m
%% do linear scan of the bucket
%%
%%% If a file error occurs on a working dets file, update_mode is set
%%% to the error tuple. When in 'error' mode, the free lists are not
%%% written, and a repair is forced next time the file is opened.
-record(dets_cont, {
what, % object | bindings | select | bchunk
no_objs, % requested number of objects: default | integer() > 0
bin, % small chunk not consumed, or 'eof' at end-of-file
alloc, % the part of the file not yet scanned, mostly a binary
tab,
match_program % true | compiled_match_spec() | undefined
}).
-record(open_args, {
file,
type,
keypos,
repair,
min_no_slots,
max_no_slots,
ram_file,
delayed_write,
auto_save,
access,
version,
debug
}).
-define(PATTERN_TO_OBJECT_MATCH_SPEC(Pat), [{Pat,[],['$_']}]).
-define(PATTERN_TO_BINDINGS_MATCH_SPEC(Pat), [{Pat,[],['$$']}]).
-define(PATTERN_TO_TRUE_MATCH_SPEC(Pat), [{Pat,[],[true]}]).
%%-define(DEBUGM(X, Y), io:format(X, Y)).
-define(DEBUGM(X, Y), true).
%%-define(DEBUGF(X,Y), io:format(X, Y)).
-define(DEBUGF(X,Y), void).
%%-define(PROFILE(C), C).
-define(PROFILE(C), void).
%%% Some further debug code was added in R12B-1 (stdlib-1.15.1):
%%% - there is a new open_file() option 'debug';
%%% - there is a new OS environment variable 'DETS_DEBUG';
%%% - verbose(true) implies that info messages are written onto
%%% the error log whenever an unsafe traversal is started.
%%% The 'debug' mode (set by the open_file() option 'debug' or
%%% by os:putenv("DETS_DEBUG", "true")) implies that the results of
%%% calling pwrite() and pread() are tested to some extent. It also
%%% means a considerable overhead when it comes to RAM usage. The
%%% operation of Dets is also slowed down a bit. Note that in debug
%%% mode terms will be output on the error logger.
%%%----------------------------------------------------------------------
%%% API
%%%----------------------------------------------------------------------
add_user(Pid, Tab, Args) ->
req(Pid, {add_user, Tab, Args}).
-spec all() -> [tab_name()].
all() ->
dets_server:all().
-type cont() :: #dets_cont{}.
-spec bchunk(tab_name(), 'start' | cont()) ->
{cont(), binary() | tuple()} | '$end_of_table' | {'error', term()}.
bchunk(Tab, start) ->
badarg(treq(Tab, {bchunk_init, Tab}), [Tab, start]);
bchunk(Tab, #dets_cont{bin = eof, tab = Tab}) ->
'$end_of_table';
bchunk(Tab, #dets_cont{what = bchunk, tab = Tab} = State) ->
badarg(treq(Tab, {bchunk, State}), [Tab, State]);
bchunk(Tab, Term) ->
erlang:error(badarg, [Tab, Term]).
-spec close(tab_name()) -> 'ok' | {'error', term()}.
close(Tab) ->
case dets_server:close(Tab) of
badarg -> % Should not happen.
{error, not_owner}; % Backwards compatibility...
Reply ->
Reply
end.
-spec delete(tab_name(), term()) -> 'ok' | {'error', term()}.
delete(Tab, Key) ->
badarg(treq(Tab, {delete_key, [Key]}), [Tab, Key]).
-spec delete_all_objects(tab_name()) -> 'ok' | {'error', term()}.
delete_all_objects(Tab) ->
case treq(Tab, delete_all_objects) of
badarg ->
erlang:error(badarg, [Tab]);
fixed ->
match_delete(Tab, '_');
Reply ->
Reply
end.
-spec delete_object(tab_name(), object()) -> 'ok' | {'error', term()}.
delete_object(Tab, O) ->
badarg(treq(Tab, {delete_object, [O]}), [Tab, O]).
%% Given a filename, fsck it. Debug.
fsck(Fname) ->
fsck(Fname, default).
fsck(Fname, Version) ->
catch begin
{ok, Fd, FH} = read_file_header(Fname, read, false),
?DEBUGF("FileHeader: ~p~n", [FH]),
case (FH#fileheader.mod):check_file_header(FH, Fd) of
{error, not_closed} ->
fsck(Fd, make_ref(), Fname, FH, default, default, Version);
{ok, _Head, _Extra} ->
fsck(Fd, make_ref(), Fname, FH, default, default, Version);
Error ->
Error
end
end.
-spec first(tab_name()) -> term() | '$end_of_table'.
first(Tab) ->
badarg_exit(treq(Tab, first), [Tab]).
-spec foldr(fun((object(), Acc) -> Acc), Acc, tab_name()) -> Acc | {'error', term()}.
foldr(Fun, Acc, Tab) ->
foldl(Fun, Acc, Tab).
-spec foldl(fun((object(), Acc) -> Acc), Acc, tab_name()) -> Acc | {'error', term()}.
foldl(Fun, Acc, Tab) ->
Ref = make_ref(),
do_traverse(Fun, Acc, Tab, Ref).
-spec from_ets(tab_name(), ets:tab()) -> 'ok' | {'error', term()}.
from_ets(DTab, ETab) ->
ets:safe_fixtable(ETab, true),
Spec = ?PATTERN_TO_OBJECT_MATCH_SPEC('_'),
LC = ets:select(ETab, Spec, 100),
InitFun = from_ets_fun(LC, ETab),
Reply = treq(DTab, {initialize, InitFun, term, default}),
ets:safe_fixtable(ETab, false),
case Reply of
{thrown, Thrown} -> throw(Thrown);
Else -> badarg(Else, [DTab, ETab])
end.
from_ets_fun(LC, ETab) ->
fun(close) ->
ok;
(read) when LC =:= '$end_of_table' ->
end_of_input;
(read) ->
{L, C} = LC,
{L, from_ets_fun(ets:select(C), ETab)}
end.
info(Tab) ->
case catch dets_server:get_pid(Tab) of
{'EXIT', _Reason} ->
undefined;
Pid ->
undefined(req(Pid, info))
end.
info(Tab, owner) ->
case catch dets_server:get_pid(Tab) of
Pid when is_pid(Pid) ->
Pid;
_ ->
undefined
end;
info(Tab, users) -> % undocumented
case dets_server:users(Tab) of
[] ->
undefined;
Users ->
Users
end;
info(Tab, Tag) ->
case catch dets_server:get_pid(Tab) of
{'EXIT', _Reason} ->
undefined;
Pid ->
undefined(req(Pid, {info, Tag}))
end.
init_table(Tab, InitFun) ->
init_table(Tab, InitFun, []).
init_table(Tab, InitFun, Options) when is_function(InitFun) ->
case options(Options, [format, min_no_slots]) of
{badarg,_} ->
erlang:error(badarg, [Tab, InitFun, Options]);
[Format, MinNoSlots] ->
case treq(Tab, {initialize, InitFun, Format, MinNoSlots}) of
{thrown, Thrown} -> throw(Thrown);
Else -> badarg(Else, [Tab, InitFun, Options])
end
end;
init_table(Tab, InitFun, Options) ->
erlang:error(badarg, [Tab, InitFun, Options]).
insert(Tab, Objs) when is_list(Objs) ->
badarg(treq(Tab, {insert, Objs}), [Tab, Objs]);
insert(Tab, Obj) ->
badarg(treq(Tab, {insert, [Obj]}), [Tab, Obj]).
insert_new(Tab, Objs) when is_list(Objs) ->
badarg(treq(Tab, {insert_new, Objs}), [Tab, Objs]);
insert_new(Tab, Obj) ->
badarg(treq(Tab, {insert_new, [Obj]}), [Tab, Obj]).
internal_close(Pid) ->
req(Pid, close).
internal_open(Pid, Ref, Args) ->
req(Pid, {internal_open, Ref, Args}).
is_compatible_bchunk_format(Tab, Term) ->
badarg(treq(Tab, {is_compatible_bchunk_format, Term}), [Tab, Term]).
is_dets_file(FileName) ->
case catch read_file_header(FileName, read, false) of
{ok, Fd, FH} ->
file:close(Fd),
FH#fileheader.cookie =:= ?MAGIC;
{error, {tooshort, _}} ->
false;
{error, {not_a_dets_file, _}} ->
false;
Other ->
Other
end.
lookup(Tab, Key) ->
badarg(treq(Tab, {lookup_keys, [Key]}), [Tab, Key]).
%% Not public.
lookup_keys(Tab, Keys) ->
case catch lists:usort(Keys) of
UKeys when is_list(UKeys), UKeys =/= [] ->
badarg(treq(Tab, {lookup_keys, UKeys}), [Tab, Keys]);
_Else ->
erlang:error(badarg, [Tab, Keys])
end.
match(Tab, Pat) ->
badarg(safe_match(Tab, Pat, bindings), [Tab, Pat]).
match(Tab, Pat, N) ->
badarg(init_chunk_match(Tab, Pat, bindings, N), [Tab, Pat, N]).
match(State) when State#dets_cont.what =:= bindings ->
badarg(chunk_match(State), [State]);
match(Term) ->
erlang:error(badarg, [Term]).
-spec match_delete(tab_name(), pattern()) ->
non_neg_integer() | 'ok' | {'error', term()}.
match_delete(Tab, Pat) ->
badarg(match_delete(Tab, Pat, delete), [Tab, Pat]).
match_delete(Tab, Pat, What) ->
safe_fixtable(Tab, true),
case compile_match_spec(What, Pat) of
{Spec, MP} ->
Proc = dets_server:get_pid(Tab),
R = req(Proc, {match_delete_init, MP, Spec}),
do_match_delete(Tab, Proc, R, What, 0);
badarg ->
badarg
end.
do_match_delete(Tab, _Proc, {done, N1}, select, N) ->
safe_fixtable(Tab, false),
N + N1;
do_match_delete(Tab, _Proc, {done, _N1}, _What, _N) ->
safe_fixtable(Tab, false),
ok;
do_match_delete(Tab, Proc, {cont, State, N1}, What, N) ->
do_match_delete(Tab, Proc, req(Proc, {match_delete, State}), What, N+N1);
do_match_delete(Tab, _Proc, Error, _What, _N) ->
safe_fixtable(Tab, false),
Error.
match_object(Tab, Pat) ->
badarg(safe_match(Tab, Pat, object), [Tab, Pat]).
match_object(Tab, Pat, N) ->
badarg(init_chunk_match(Tab, Pat, object, N), [Tab, Pat, N]).
match_object(State) when State#dets_cont.what =:= object ->
badarg(chunk_match(State), [State]);
match_object(Term) ->
erlang:error(badarg, [Term]).
member(Tab, Key) ->
badarg(treq(Tab, {member, Key}), [Tab, Key]).
next(Tab, Key) ->
badarg_exit(treq(Tab, {next, Key}), [Tab, Key]).
%% Assuming that a file already exists, open it with the
%% parameters as already specified in the file itself.
%% Return a ref leading to the file.
open_file(File) ->
case dets_server:open_file(to_list(File)) of
badarg -> % Should not happen.
erlang:error(dets_process_died, [File]);
Reply ->
einval(Reply, [File])
end.
open_file(Tab, Args) when is_list(Args) ->
case catch defaults(Tab, Args) of
OpenArgs when is_record(OpenArgs, open_args) ->
case dets_server:open_file(Tab, OpenArgs) of
badarg -> % Should not happen.
erlang:error(dets_process_died, [Tab, Args]);
Reply ->
einval(Reply, [Tab, Args])
end;
_ ->
erlang:error(badarg, [Tab, Args])
end;
open_file(Tab, Arg) ->
open_file(Tab, [Arg]).
pid2name(Pid) ->
dets_server:pid2name(Pid).
remove_user(Pid, From) ->
req(Pid, {close, From}).
repair_continuation(#dets_cont{match_program = B}=Cont, MS)
when is_binary(B) ->
case ets:is_compiled_ms(B) of
true ->
Cont;
false ->
Cont#dets_cont{match_program = ets:match_spec_compile(MS)}
end;
repair_continuation(#dets_cont{}=Cont, _MS) ->
Cont;
repair_continuation(T, MS) ->
erlang:error(badarg, [T, MS]).
safe_fixtable(Tab, Bool) when Bool; not Bool ->
badarg(treq(Tab, {safe_fixtable, Bool}), [Tab, Bool]);
safe_fixtable(Tab, Term) ->
erlang:error(badarg, [Tab, Term]).
select(Tab, Pat) ->
badarg(safe_match(Tab, Pat, select), [Tab, Pat]).
select(Tab, Pat, N) ->
badarg(init_chunk_match(Tab, Pat, select, N), [Tab, Pat, N]).
select(State) when State#dets_cont.what =:= select ->
badarg(chunk_match(State), [State]);
select(Term) ->
erlang:error(badarg, [Term]).
select_delete(Tab, Pat) ->
badarg(match_delete(Tab, Pat, select), [Tab, Pat]).
slot(Tab, Slot) when is_integer(Slot), Slot >= 0 ->
badarg(treq(Tab, {slot, Slot}), [Tab, Slot]);
slot(Tab, Term) ->
erlang:error(badarg, [Tab, Term]).
start() ->
dets_server:start().
stop() ->
dets_server:stop().
istart_link(Server) ->
{ok, proc_lib:spawn_link(dets, init, [self(), Server])}.
sync(Tab) ->
badarg(treq(Tab, sync), [Tab]).
table(Tab) ->
table(Tab, []).
table(Tab, Opts) ->
case options(Opts, [traverse, n_objects]) of
{badarg,_} ->
erlang:error(badarg, [Tab, Opts]);
[Traverse, NObjs] ->
TF = case Traverse of
first_next ->
fun() -> qlc_next(Tab, first(Tab)) end;
select ->
fun(MS) -> qlc_select(select(Tab, MS, NObjs)) end;
{select, MS} ->
fun() -> qlc_select(select(Tab, MS, NObjs)) end
end,
PreFun = fun(_) -> safe_fixtable(Tab, true) end,
PostFun = fun() -> safe_fixtable(Tab, false) end,
InfoFun = fun(Tag) -> table_info(Tab, Tag) end,
%% lookup_keys is not public, but convenient
LookupFun =
case Traverse of
{select, _MS} ->
undefined;
_ ->
fun(_KeyPos, [K]) -> lookup(Tab, K);
(_KeyPos, Ks) -> lookup_keys(Tab, Ks)
end
end,
FormatFun =
fun({all, _NElements, _ElementFun}) ->
As = [Tab | [Opts || _ <- [[]], Opts =/= []]],
{?MODULE, table, As};
({match_spec, MS}) ->
{?MODULE, table, [Tab, [{traverse, {select, MS}} |
listify(Opts)]]};
({lookup, _KeyPos, [Value], _NElements, ElementFun}) ->
io_lib:format("~w:lookup(~w, ~w)",
[?MODULE, Tab, ElementFun(Value)]);
({lookup, _KeyPos, Values, _NElements, ElementFun}) ->
Vals = [ElementFun(V) || V <- Values],
io_lib:format("lists:flatmap(fun(V) -> "
"~w:lookup(~w, V) end, ~w)",
[?MODULE, Tab, Vals])
end,
qlc:table(TF, [{pre_fun, PreFun}, {post_fun, PostFun},
{info_fun, InfoFun}, {format_fun, FormatFun},
{key_equality, '=:='},
{lookup_fun, LookupFun}])
end.
qlc_next(_Tab, '$end_of_table') ->
[];
qlc_next(Tab, Key) ->
case lookup(Tab, Key) of
Objects when is_list(Objects) ->
Objects ++ fun() -> qlc_next(Tab, next(Tab, Key)) end;
Error ->
%% Do what first and next do.
exit(Error)
end.
qlc_select('$end_of_table') ->
[];
qlc_select({Objects, Cont}) when is_list(Objects) ->
Objects ++ fun() -> qlc_select(select(Cont)) end;
qlc_select(Error) ->
Error.
table_info(Tab, num_of_objects) ->
info(Tab, size);
table_info(Tab, keypos) ->
info(Tab, keypos);
table_info(Tab, is_unique_objects) ->
info(Tab, type) =/= duplicate_bag;
table_info(_Tab, _) ->
undefined.
%% End of table/2.
to_ets(DTab, ETab) ->
case ets:info(ETab, protection) of
undefined ->
erlang:error(badarg, [DTab, ETab]);
_ ->
Fun = fun(X, T) -> true = ets:insert(T, X), T end,
foldl(Fun, ETab, DTab)
end.
traverse(Tab, Fun) ->
Ref = make_ref(),
TFun =
fun(O, Acc) ->
case Fun(O) of
continue ->
Acc;
{continue, Val} ->
[Val | Acc];
{done, Value} ->
throw({Ref, [Value | Acc]});
Other ->
throw({Ref, Other})
end
end,
do_traverse(TFun, [], Tab, Ref).
update_counter(Tab, Key, C) ->
badarg(treq(Tab, {update_counter, Key, C}), [Tab, Key, C]).
verbose() ->
verbose(true).
verbose(What) ->
ok = dets_server:verbose(What),
All = dets_server:all(),
Fun = fun(Tab) -> treq(Tab, {set_verbose, What}) end,
lists:foreach(Fun, All),
All.
%% Where in the (open) table is Object located?
%% The address of the first matching object is returned.
%% Format 9 returns the address of the object collection.
%% -> {ok, Address} | false
where(Tab, Object) ->
badarg(treq(Tab, {where, Object}), [Tab, Object]).
do_traverse(Fun, Acc, Tab, Ref) ->
safe_fixtable(Tab, true),
Proc = dets_server:get_pid(Tab),
try
do_trav(Proc, Acc, Fun)
catch {Ref, Result} ->
Result
after
safe_fixtable(Tab, false)
end.
do_trav(Proc, Acc, Fun) ->
{Spec, MP} = compile_match_spec(object, '_'),
%% MP not used
case req(Proc, {match, MP, Spec, default}) of
{cont, State} ->
do_trav(State, Proc, Acc, Fun);
Error ->
Error
end.
do_trav(#dets_cont{bin = eof}, _Proc, Acc, _Fun) ->
Acc;
do_trav(State, Proc, Acc, Fun) ->
case req(Proc, {match_init, State}) of
{cont, {Bins, NewState}} ->
do_trav_bins(NewState, Proc, Acc, Fun, lists:reverse(Bins));
Error ->
Error
end.
do_trav_bins(State, Proc, Acc, Fun, []) ->
do_trav(State, Proc, Acc, Fun);
do_trav_bins(State, Proc, Acc, Fun, [Bin | Bins]) ->
%% Unpack one binary at a time, using the client's heap.
case catch binary_to_term(Bin) of
{'EXIT', _} ->
req(Proc, {corrupt, dets_utils:bad_object(do_trav_bins, Bin)});
Term ->
NewAcc = Fun(Term, Acc),
do_trav_bins(State, Proc, NewAcc, Fun, Bins)
end.
safe_match(Tab, Pat, What) ->
safe_fixtable(Tab, true),
R = do_safe_match(init_chunk_match(Tab, Pat, What, default), []),
safe_fixtable(Tab, false),
R.
do_safe_match({error, Error}, _L) ->
{error, Error};
do_safe_match({L, C}, LL) ->
do_safe_match(chunk_match(C), L++LL);
do_safe_match('$end_of_table', L) ->
L;
do_safe_match(badarg, _L) ->
badarg.
%% What = object | bindings | select
init_chunk_match(Tab, Pat, What, N) when is_integer(N), N >= 0;
N =:= default ->
case compile_match_spec(What, Pat) of
{Spec, MP} ->
case req(dets_server:get_pid(Tab), {match, MP, Spec, N}) of
{done, L} ->
{L, #dets_cont{tab = Tab, what = What, bin = eof}};
{cont, State} ->
chunk_match(State#dets_cont{what = What, tab = Tab});
Error ->
Error
end;
badarg ->
badarg
end;
init_chunk_match(_Tab, _Pat, _What, _) ->
badarg.
chunk_match(State) ->
case catch dets_server:get_pid(State#dets_cont.tab) of
{'EXIT', _Reason} ->
badarg;
_Proc when State#dets_cont.bin =:= eof ->
'$end_of_table';
Proc ->
case req(Proc, {match_init, State}) of
{cont, {Bins, NewState}} ->
MP = NewState#dets_cont.match_program,
case catch do_foldl_bins(Bins, MP) of
{'EXIT', _} ->
case ets:is_compiled_ms(MP) of
true ->
Bad = dets_utils:bad_object(chunk_match,
Bins),
req(Proc, {corrupt, Bad});
false ->
badarg
end;
[] ->
chunk_match(NewState);
Terms ->
{Terms, NewState}
end;
Error ->
Error
end
end.
do_foldl_bins(Bins, true) ->
foldl_bins(Bins, []);
do_foldl_bins(Bins, MP) ->
foldl_bins(Bins, MP, []).
foldl_bins([], Terms) ->
%% Preserve time order (version 9).
Terms;
foldl_bins([Bin | Bins], Terms) ->
foldl_bins(Bins, [binary_to_term(Bin) | Terms]).
foldl_bins([], _MP, Terms) ->
%% Preserve time order (version 9).
Terms;
foldl_bins([Bin | Bins], MP, Terms) ->
Term = binary_to_term(Bin),
case ets:match_spec_run([Term], MP) of
[] ->
foldl_bins(Bins, MP, Terms);
[Result] ->
foldl_bins(Bins, MP, [Result | Terms])
end.
%% -> {Spec, binary()} | badarg
compile_match_spec(select, ?PATTERN_TO_OBJECT_MATCH_SPEC('_') = Spec) ->
{Spec, true};
compile_match_spec(select, Spec) ->
case catch ets:match_spec_compile(Spec) of
X when is_binary(X) ->
{Spec, X};
_ ->
badarg
end;
compile_match_spec(object, Pat) ->
compile_match_spec(select, ?PATTERN_TO_OBJECT_MATCH_SPEC(Pat));
compile_match_spec(bindings, Pat) ->
compile_match_spec(select, ?PATTERN_TO_BINDINGS_MATCH_SPEC(Pat));
compile_match_spec(delete, Pat) ->
compile_match_spec(select, ?PATTERN_TO_TRUE_MATCH_SPEC(Pat)).
%% Process the args list as provided to open_file/2.
defaults(Tab, Args) ->
Defaults0 = #open_args{file = to_list(Tab),
type = set,
keypos = 1,
repair = true,
min_no_slots = default,
max_no_slots = default,
ram_file = false,
delayed_write = ?DEFAULT_CACHE,
auto_save = timer:minutes(?DEFAULT_AUTOSAVE),
access = read_write,
version = default,
debug = false},
Fun = fun repl/2,
Defaults = lists:foldl(Fun, Defaults0, Args),
case Defaults#open_args.version of
8 ->
Defaults#open_args{max_no_slots = default};
_ ->
is_comp_min_max(Defaults)
end.
to_list(T) when is_atom(T) -> atom_to_list(T);
to_list(T) -> T.
repl({access, A}, Defs) ->
mem(A, [read, read_write]),
Defs#open_args{access = A};
repl({auto_save, Int}, Defs) when is_integer(Int), Int >= 0 ->
Defs#open_args{auto_save = Int};
repl({auto_save, infinity}, Defs) ->
Defs#open_args{auto_save =infinity};
repl({cache_size, Int}, Defs) when is_integer(Int), Int >= 0 ->
%% Recognized, but ignored.
Defs;
repl({cache_size, infinity}, Defs) ->
Defs;
repl({delayed_write, default}, Defs) ->
Defs#open_args{delayed_write = ?DEFAULT_CACHE};
repl({delayed_write, {Delay,Size} = C}, Defs)
when is_integer(Delay), Delay >= 0, is_integer(Size), Size >= 0 ->
Defs#open_args{delayed_write = C};
repl({estimated_no_objects, I}, Defs) ->
repl({min_no_slots, I}, Defs);
repl({file, File}, Defs) ->
Defs#open_args{file = to_list(File)};
repl({keypos, P}, Defs) when is_integer(P), P > 0 ->
Defs#open_args{keypos =P};
repl({max_no_slots, I}, Defs) ->
%% Version 9 only.
MaxSlots = is_max_no_slots(I),
Defs#open_args{max_no_slots = MaxSlots};
repl({min_no_slots, I}, Defs) ->
MinSlots = is_min_no_slots(I),
Defs#open_args{min_no_slots = MinSlots};
repl({ram_file, Bool}, Defs) ->
mem(Bool, [true, false]),
Defs#open_args{ram_file = Bool};
repl({repair, T}, Defs) ->
mem(T, [true, false, force]),
Defs#open_args{repair = T};
repl({type, T}, Defs) ->
mem(T, [set, bag, duplicate_bag]),
Defs#open_args{type =T};
repl({version, Version}, Defs) ->
V = is_version(Version),
Defs#open_args{version = V};
repl({debug, Bool}, Defs) ->
%% Not documented.
mem(Bool, [true, false]),
Defs#open_args{debug = Bool};
repl({_, _}, _) ->
exit(badarg).
is_min_no_slots(default) -> default;
is_min_no_slots(I) when is_integer(I), I >= ?DEFAULT_MIN_NO_SLOTS -> I;
is_min_no_slots(I) when is_integer(I), I >= 0 -> ?DEFAULT_MIN_NO_SLOTS.
is_max_no_slots(default) -> default;
is_max_no_slots(I) when is_integer(I), I > 0, I < 1 bsl 31 -> I.
is_comp_min_max(Defs) ->
#open_args{max_no_slots = Max, min_no_slots = Min, version = V} = Defs,
case V of
_ when Min =:= default -> Defs;
_ when Max =:= default -> Defs;
_ -> true = Min =< Max, Defs
end.
is_version(default) -> default;
is_version(8) -> 8;
is_version(9) -> 9.
mem(X, L) ->
case lists:member(X, L) of
true -> true;
false -> exit(badarg)
end.
options(Options, Keys) when is_list(Options) ->
options(Options, Keys, []);
options(Option, Keys) ->
options([Option], Keys, []).
options(Options, [Key | Keys], L) when is_list(Options) ->
V = case lists:keysearch(Key, 1, Options) of
{value, {format, Format}} when Format =:= term;
Format =:= bchunk ->
{ok, Format};
{value, {min_no_slots, I}} ->
case catch is_min_no_slots(I) of
{'EXIT', _} -> badarg;
MinNoSlots -> {ok, MinNoSlots}
end;
{value, {n_objects, default}} ->
{ok, default_option(Key)};
{value, {n_objects, NObjs}} when is_integer(NObjs),
NObjs >= 1 ->
{ok, NObjs};
{value, {traverse, select}} ->
{ok, select};
{value, {traverse, {select, MS}}} ->
{ok, {select, MS}};
{value, {traverse, first_next}} ->
{ok, first_next};
{value, {Key, _}} ->
badarg;
false ->
Default = default_option(Key),
{ok, Default}
end,
case V of
badarg ->
{badarg, Key};
{ok, Value} ->
NewOptions = lists:keydelete(Key, 1, Options),
options(NewOptions, Keys, [Value | L])
end;
options([], [], L) ->
lists:reverse(L);
options(Options, _, _L) ->
{badarg,Options}.
default_option(format) -> term;
default_option(min_no_slots) -> default;
default_option(traverse) -> select;
default_option(n_objects) -> default.
listify(L) when is_list(L) ->
L;
listify(T) ->
[T].
treq(Tab, R) ->
case catch dets_server:get_pid(Tab) of
Pid when is_pid(Pid) ->
req(Pid, R);
_ ->
badarg
end.
req(Proc, R) ->
Ref = erlang:monitor(process, Proc),
Proc ! ?DETS_CALL(self(), R),
receive
{'DOWN', Ref, process, Proc, _Info} ->
badarg;
{Proc, Reply} ->
erlang:demonitor(Ref),
receive
{'DOWN', Ref, process, Proc, _Reason} ->
Reply
after 0 ->
Reply
end
end.
%% Inlined.
einval({error, {file_error, _, einval}}, A) ->
erlang:error(badarg, A);
einval({error, {file_error, _, badarg}}, A) ->
erlang:error(badarg, A);
einval(Reply, _A) ->
Reply.
%% Inlined.
badarg(badarg, A) ->
erlang:error(badarg, A);
badarg(Reply, _A) ->
Reply.
%% Inlined.
undefined(badarg) ->
undefined;
undefined(Reply) ->
Reply.
%% Inlined.
badarg_exit(badarg, A) ->
erlang:error(badarg, A);
badarg_exit({ok, Reply}, _A) ->
Reply;
badarg_exit(Reply, _A) ->
exit(Reply).
%%%-----------------------------------------------------------------
%%% Server functions
%%%-----------------------------------------------------------------
init(Parent, Server) ->
process_flag(trap_exit, true),
open_file_loop(#head{parent = Parent, server = Server}).
open_file_loop(Head) ->
open_file_loop(Head, 0).
open_file_loop(Head, N) when element(1, Head#head.update_mode) =:= error ->
open_file_loop2(Head, N);
open_file_loop(Head, N) ->
receive
%% When the table is fixed it can be assumed that at least one
%% traversal is in progress. To speed the traversal up three
%% things have been done:
%% - prioritize match_init, bchunk, next, and match_delete_init;
%% - do not peek the message queue for updates;
%% - wait 1 ms after each update.
%% next is normally followed by lookup, but since lookup is also
%% used when not traversing the table, it is not prioritized.
?DETS_CALL(From, {match_init, _State} = Op) ->
do_apply_op(Op, From, Head, N);
?DETS_CALL(From, {bchunk, _State} = Op) ->
do_apply_op(Op, From, Head, N);
?DETS_CALL(From, {next, _Key} = Op) ->
do_apply_op(Op, From, Head, N);
?DETS_CALL(From, {match_delete_init, _MP, _Spec} = Op) ->
do_apply_op(Op, From, Head, N);
{'EXIT', Pid, Reason} when Pid =:= Head#head.parent ->
%% Parent orders shutdown.
_NewHead = do_stop(Head),
exit(Reason);
{'EXIT', Pid, Reason} when Pid =:= Head#head.server ->
%% The server is gone.
_NewHead = do_stop(Head),
exit(Reason);
{'EXIT', Pid, _Reason} ->
%% A process fixing the table exits.
H2 = remove_fix(Head, Pid, close),
open_file_loop(H2, N);
{system, From, Req} ->
sys:handle_system_msg(Req, From, Head#head.parent,
?MODULE, [], Head)
after 0 ->
open_file_loop2(Head, N)
end.
open_file_loop2(Head, N) ->
receive
?DETS_CALL(From, Op) ->
do_apply_op(Op, From, Head, N);
{'EXIT', Pid, Reason} when Pid =:= Head#head.parent ->
%% Parent orders shutdown.
_NewHead = do_stop(Head),
exit(Reason);
{'EXIT', Pid, Reason} when Pid =:= Head#head.server ->
%% The server is gone.
_NewHead = do_stop(Head),
exit(Reason);
{'EXIT', Pid, _Reason} ->
%% A process fixing the table exits.
H2 = remove_fix(Head, Pid, close),
open_file_loop(H2, N);
{system, From, Req} ->
sys:handle_system_msg(Req, From, Head#head.parent,
?MODULE, [], Head);
Message ->
error_logger:format("** dets: unexpected message"
"(ignored): ~w~n", [Message]),
open_file_loop(Head, N)
end.
do_apply_op(Op, From, Head, N) ->
try apply_op(Op, From, Head, N) of
ok ->
open_file_loop(Head, N);
{N2, H2} when is_record(H2, head), is_integer(N2) ->
open_file_loop(H2, N2);
H2 when is_record(H2, head) ->
open_file_loop(H2, N);
{{more,From1,Op1,N1}, NewHead} ->
do_apply_op(Op1, From1, NewHead, N1)
catch
exit:normal ->
exit(normal);
_:Bad ->
Name = Head#head.name,
case dets_utils:debug_mode() of
true ->
%% If stream_op/5 found more requests, this is not
%% the last operation.
error_logger:format
("** dets: Bug was found when accessing table ~w,~n"
"** dets: operation was ~p and reply was ~w.~n"
"** dets: Stacktrace: ~w~n",
[Name, Op, Bad, erlang:get_stacktrace()]);
false ->
error_logger:format
("** dets: Bug was found when accessing table ~w~n",
[Name])
end,
if
From =/= self() ->
From ! {self(), {error, {dets_bug, Name, Op, Bad}}};
true -> % auto_save | may_grow | {delayed_write, _}
ok
end,
open_file_loop(Head, N)
end.
apply_op(Op, From, Head, N) ->
case Op of
{add_user, Tab, OpenArgs}->
#open_args{file = Fname, type = Type, keypos = Keypos,
ram_file = Ram, access = Access,
version = Version} = OpenArgs,
VersionOK = (Version =:= default) or
(Head#head.version =:= Version),
%% min_no_slots and max_no_slots are not tested
Res = if
Tab =:= Head#head.name,
Head#head.keypos =:= Keypos,
Head#head.type =:= Type,
Head#head.ram_file =:= Ram,
Head#head.access =:= Access,
VersionOK,
Fname =:= Head#head.filename ->
ok;
true ->
err({error, incompatible_arguments})
end,
From ! {self(), Res},
ok;
auto_save ->
case Head#head.update_mode of
saved ->
Head;
{error, _Reason} ->
Head;
_Dirty when N =:= 0 -> % dirty or new_dirty
%% The updates seems to have declined
dets_utils:vformat("** dets: Auto save of ~p\n",
[Head#head.name]),
{NewHead, _Res} = perform_save(Head, true),
erlang:garbage_collect(),
{0, NewHead};
dirty ->
%% Reset counter and try later
start_auto_save_timer(Head),
{0, Head}
end;
close ->
From ! {self(), fclose(Head)},
_NewHead = unlink_fixing_procs(Head),
?PROFILE(ep:done()),
exit(normal);
{close, Pid} ->
%% Used from dets_server when Pid has closed the table,
%% but the table is still opened by some process.
NewHead = remove_fix(Head, Pid, close),
From ! {self(), status(NewHead)},
NewHead;
{corrupt, Reason} ->
{H2, Error} = dets_utils:corrupt_reason(Head, Reason),
From ! {self(), Error},
H2;
{delayed_write, WrTime} ->
delayed_write(Head, WrTime);
info ->
{H2, Res} = finfo(Head),
From ! {self(), Res},
H2;
{info, Tag} ->
{H2, Res} = finfo(Head, Tag),
From ! {self(), Res},
H2;
{is_compatible_bchunk_format, Term} ->
Res = test_bchunk_format(Head, Term),
From ! {self(), Res},
ok;
{internal_open, Ref, Args} ->
?PROFILE(ep:do()),
case do_open_file(Args, Head#head.parent, Head#head.server,Ref) of
{ok, H2} ->
From ! {self(), ok},
H2;
Error ->
From ! {self(), Error},
exit(normal)
end;
may_grow when Head#head.update_mode =/= saved ->
if
Head#head.update_mode =:= dirty ->
%% Won't grow more if the table is full.
{H2, _Res} =
(Head#head.mod):may_grow(Head, 0, many_times),
{N + 1, H2};
true ->
ok
end;
{set_verbose, What} ->
set_verbose(What),
From ! {self(), ok},
ok;
{where, Object} ->
{H2, Res} = where_is_object(Head, Object),
From ! {self(), Res},
H2;
_Message when element(1, Head#head.update_mode) =:= error ->
From ! {self(), status(Head)},
ok;
%% The following messages assume that the status of the table is OK.
{bchunk_init, Tab} ->
{H2, Res} = do_bchunk_init(Head, Tab),
From ! {self(), Res},
H2;
{bchunk, State} ->
{H2, Res} = do_bchunk(Head, State),
From ! {self(), Res},
H2;
delete_all_objects ->
{H2, Res} = fdelete_all_objects(Head),
From ! {self(), Res},
erlang:garbage_collect(),
{0, H2};
{delete_key, Keys} when Head#head.update_mode =:= dirty ->
if
Head#head.version =:= 8 ->
{H2, Res} = fdelete_key(Head, Keys),
From ! {self(), Res},
{N + 1, H2};
true ->
stream_op(Op, From, [], Head, N)
end;
{delete_object, Objs} when Head#head.update_mode =:= dirty ->
case check_objects(Objs, Head#head.keypos) of
true when Head#head.version =:= 8 ->
{H2, Res} = fdelete_object(Head, Objs),
From ! {self(), Res},
{N + 1, H2};
true ->
stream_op(Op, From, [], Head, N);
false ->
From ! {self(), badarg},
ok
end;
first ->
{H2, Res} = ffirst(Head),
From ! {self(), Res},
H2;
{initialize, InitFun, Format, MinNoSlots} ->
{H2, Res} = finit(Head, InitFun, Format, MinNoSlots),
From ! {self(), Res},
erlang:garbage_collect(),
H2;
{insert, Objs} when Head#head.update_mode =:= dirty ->
case check_objects(Objs, Head#head.keypos) of
true when Head#head.version =:= 8 ->
{H2, Res} = finsert(Head, Objs),
From ! {self(), Res},
{N + 1, H2};
true ->
stream_op(Op, From, [], Head, N);
false ->
From ! {self(), badarg},
ok
end;
{insert_new, Objs} when Head#head.update_mode =:= dirty ->
{H2, Res} = finsert_new(Head, Objs),
From ! {self(), Res},
{N + 1, H2};
{lookup_keys, Keys} when Head#head.version =:= 8 ->
{H2, Res} = flookup_keys(Head, Keys),
From ! {self(), Res},
H2;
{lookup_keys, _Keys} ->
stream_op(Op, From, [], Head, N);
{match_init, State} ->
{H2, Res} = fmatch_init(Head, State),
From ! {self(), Res},
H2;
{match, MP, Spec, NObjs} ->
{H2, Res} = fmatch(Head, MP, Spec, NObjs),
From ! {self(), Res},
H2;
{member, Key} when Head#head.version =:= 8 ->
{H2, Res} = fmember(Head, Key),
From ! {self(), Res},
H2;
{member, _Key} = Op ->
stream_op(Op, From, [], Head, N);
{next, Key} ->
{H2, Res} = fnext(Head, Key),
From ! {self(), Res},
H2;
{match_delete, State} when Head#head.update_mode =:= dirty ->
{H2, Res} = fmatch_delete(Head, State),
From ! {self(), Res},
{N + 1, H2};
{match_delete_init, MP, Spec} when Head#head.update_mode =:= dirty ->
{H2, Res} = fmatch_delete_init(Head, MP, Spec),
From ! {self(), Res},
{N + 1, H2};
{safe_fixtable, Bool} ->
NewHead = do_safe_fixtable(Head, From, Bool),
From ! {self(), ok},
NewHead;
{slot, Slot} ->
{H2, Res} = fslot(Head, Slot),
From ! {self(), Res},
H2;
sync ->
{NewHead, Res} = perform_save(Head, true),
From ! {self(), Res},
erlang:garbage_collect(),
{0, NewHead};
{update_counter, Key, Incr} when Head#head.update_mode =:= dirty ->
{NewHead, Res} = do_update_counter(Head, Key, Incr),
From ! {self(), Res},
{N + 1, NewHead};
WriteOp when Head#head.update_mode =:= new_dirty ->
H2 = Head#head{update_mode = dirty},
apply_op(WriteOp, From, H2, 0);
WriteOp when Head#head.access =:= read_write,
Head#head.update_mode =:= saved ->
case catch (Head#head.mod):mark_dirty(Head) of
ok ->
start_auto_save_timer(Head),
H2 = Head#head{update_mode = dirty},
apply_op(WriteOp, From, H2, 0);
{NewHead, Error} when is_record(NewHead, head) ->
From ! {self(), Error},
NewHead
end;
WriteOp when is_tuple(WriteOp), Head#head.access =:= read ->
Reason = {access_mode, Head#head.filename},
From ! {self(), err({error, Reason})},
ok
end.
start_auto_save_timer(Head) when Head#head.auto_save =:= infinity ->
ok;
start_auto_save_timer(Head) ->
Millis = Head#head.auto_save,
erlang:send_after(Millis, self(), ?DETS_CALL(self(), auto_save)).
%% Version 9: Peek the message queue and try to evaluate several
%% lookup requests in parallel. Evalute delete_object, delete and
%% insert as well.
stream_op(Op, Pid, Pids, Head, N) ->
stream_op(Head, Pids, [], N, Pid, Op, Head#head.fixed).
stream_loop(Head, Pids, C, N, false = Fxd) ->
receive
?DETS_CALL(From, Message) ->
stream_op(Head, Pids, C, N, From, Message, Fxd)
after 0 ->
stream_end(Head, Pids, C, N, no_more)
end;
stream_loop(Head, Pids, C, N, _Fxd) ->
stream_end(Head, Pids, C, N, no_more).
stream_op(Head, Pids, C, N, Pid, {lookup_keys,Keys}, Fxd) ->
NC = [{{lookup,Pid},Keys} | C],
stream_loop(Head, Pids, NC, N, Fxd);
stream_op(Head, Pids, C, N, Pid, {insert, _Objects} = Op, Fxd) ->
NC = [Op | C],
stream_loop(Head, [Pid | Pids], NC, N, Fxd);
stream_op(Head, Pids, C, N, Pid, {insert_new, _Objects} = Op, Fxd) ->
NC = [Op | C],
stream_loop(Head, [Pid | Pids], NC, N, Fxd);
stream_op(Head, Pids, C, N, Pid, {delete_key, _Keys} = Op, Fxd) ->
NC = [Op | C],
stream_loop(Head, [Pid | Pids], NC, N, Fxd);
stream_op(Head, Pids, C, N, Pid, {delete_object, _Objects} = Op, Fxd) ->
NC = [Op | C],
stream_loop(Head, [Pid | Pids], NC, N, Fxd);
stream_op(Head, Pids, C, N, Pid, {member, Key}, Fxd) ->
NC = [{{lookup,[Pid]},[Key]} | C],
stream_loop(Head, Pids, NC, N, Fxd);
stream_op(Head, Pids, C, N, Pid, Op, _Fxd) ->
stream_end(Head, Pids, C, N, {Pid,Op}).
stream_end(Head, Pids0, C, N, Next) ->
case catch update_cache(Head, lists:reverse(C)) of
{Head1, [], PwriteList} ->
stream_end1(Pids0, Next, N, C, Head1, PwriteList);
{Head1, Found, PwriteList} ->
%% Possibly an optimization: reply to lookup requests
%% first, then write stuff. This makes it possible for
%% clients to continue while the disk is accessed.
%% (Replies to lookup requests are sent earlier than
%% replies to delete and insert requests even if the
%% latter requests were made before the lookup requests,
%% which can be confusing.)
lookup_replies(Found),
stream_end1(Pids0, Next, N, C, Head1, PwriteList);
Head1 when is_record(Head1, head) ->
stream_end2(Pids0, Pids0, Next, N, C, Head1, ok);
{Head1, Error} when is_record(Head1, head) ->
%% Dig out the processes that did lookup or member.
Fun = fun({{lookup,[Pid]},_Keys}, L) -> [Pid | L];
({{lookup,Pid},_Keys}, L) -> [Pid | L];
(_, L) -> L
end,
LPs0 = lists:foldl(Fun, [], C),
LPs = lists:usort(lists:flatten(LPs0)),
stream_end2(Pids0 ++ LPs, Pids0, Next, N, C, Head1, Error);
DetsError ->
throw(DetsError)
end.
stream_end1(Pids, Next, N, C, Head, []) ->
stream_end2(Pids, Pids, Next, N, C, Head, ok);
stream_end1(Pids, Next, N, C, Head, PwriteList) ->
{Head1, PR} = (catch dets_utils:pwrite(Head, PwriteList)),
stream_end2(Pids, Pids, Next, N, C, Head1, PR).
stream_end2([Pid | Pids], Ps, Next, N, C, Head, Reply) ->
Pid ! {self(), Reply},
stream_end2(Pids, Ps, Next, N+1, C, Head, Reply);
stream_end2([], Ps, no_more, N, C, Head, _Reply) ->
penalty(Head, Ps, C),
{N, Head};
stream_end2([], _Ps, {From, Op}, N, _C, Head, _Reply) ->
{{more,From,Op,N},Head}.
penalty(H, _Ps, _C) when H#head.fixed =:= false ->
ok;
penalty(_H, _Ps, [{{lookup,_Pids},_Keys}]) ->
ok;
penalty(#head{fixed = {_,[{Pid,_}]}}, [Pid], _C) ->
ok;
penalty(_H, _Ps, _C) ->
timer:sleep(1).
lookup_replies([{P,O}]) ->
lookup_reply(P, O);
lookup_replies(Q) ->
[{P,O} | L] = dets_utils:family(Q),
lookup_replies(P, lists:append(O), L).
lookup_replies(P, O, []) ->
lookup_reply(P, O);
lookup_replies(P, O, [{P2,O2} | L]) ->
lookup_reply(P, O),
lookup_replies(P2, lists:append(O2), L).
%% If a list of Pid then op was {member, Key}. Inlined.
lookup_reply([P], O) ->
P ! {self(), O =/= []};
lookup_reply(P, O) ->
P ! {self(), O}.
%%-----------------------------------------------------------------
%% Callback functions for system messages handling.
%%-----------------------------------------------------------------
system_continue(_Parent, _, Head) ->
open_file_loop(Head).
system_terminate(Reason, _Parent, _, Head) ->
_NewHead = do_stop(Head),
exit(Reason).
%%-----------------------------------------------------------------
%% Code for upgrade.
%%-----------------------------------------------------------------
system_code_change(State, _Module, _OldVsn, _Extra) ->
{ok, State}.
%%%----------------------------------------------------------------------
%%% Internal functions
%%%----------------------------------------------------------------------
constants(FH, FileName) ->
Version = FH#fileheader.version,
if
Version =< 8 ->
dets_v8:constants();
Version =:= 9 ->
dets_v9:constants();
true ->
throw({error, {not_a_dets_file, FileName}})
end.
%% -> {ok, Fd, fileheader()} | throw(Error)
read_file_header(FileName, Access, RamFile) ->
BF = if
RamFile ->
case file:read_file(FileName) of
{ok, B} -> B;
Err -> dets_utils:file_error(FileName, Err)
end;
true ->
FileName
end,
{ok, Fd} = dets_utils:open(BF, open_args(Access, RamFile)),
{ok, <<Version:32>>} =
dets_utils:pread_close(Fd, FileName, ?FILE_FORMAT_VERSION_POS, 4),
if
Version =< 8 ->
dets_v8:read_file_header(Fd, FileName);
Version =:= 9 ->
dets_v9:read_file_header(Fd, FileName);
true ->
throw({error, {not_a_dets_file, FileName}})
end.
fclose(Head) ->
{Head1, Res} = perform_save(Head, false),
case Head1#head.ram_file of
true ->
ignore;
false ->
dets_utils:stop_disk_map(),
file:close(Head1#head.fptr)
end,
Res.
%% -> {NewHead, Res}
perform_save(Head, DoSync) when Head#head.update_mode =:= dirty;
Head#head.update_mode =:= new_dirty ->
case catch begin
{Head1, []} = write_cache(Head),
{Head2, ok} = (Head1#head.mod):do_perform_save(Head1),
ok = ensure_written(Head2, DoSync),
{Head2#head{update_mode = saved}, ok}
end of
{NewHead, _} = Reply when is_record(NewHead, head) ->
Reply
end;
perform_save(Head, _DoSync) ->
{Head, status(Head)}.
ensure_written(Head, DoSync) when Head#head.ram_file ->
{ok, EOF} = dets_utils:position(Head, eof),
{ok, Bin} = dets_utils:pread(Head, 0, EOF, 0),
if
DoSync ->
dets_utils:write_file(Head, Bin);
not DoSync ->
case file:write_file(Head#head.filename, Bin) of
ok ->
ok;
Error ->
dets_utils:corrupt_file(Head, Error)
end
end;
ensure_written(Head, true) when not Head#head.ram_file ->
dets_utils:sync(Head);
ensure_written(Head, false) when not Head#head.ram_file ->
ok.
%% -> {NewHead, {cont(), [binary()]}} | {NewHead, Error}
do_bchunk_init(Head, Tab) ->
case catch write_cache(Head) of
{H2, []} ->
case (H2#head.mod):table_parameters(H2) of
undefined ->
{H2, {error, old_version}};
Parms ->
L = dets_utils:all_allocated(H2),
C0 = #dets_cont{no_objs = default, bin = <<>>, alloc = L},
BinParms = term_to_binary(Parms),
{H2, {C0#dets_cont{tab = Tab, what = bchunk}, [BinParms]}}
end;
{NewHead, _} = HeadError when is_record(NewHead, head) ->
HeadError
end.
%% -> {NewHead, {cont(), [binary()]}} | {NewHead, Error}
do_bchunk(Head, State) ->
case dets_v9:read_bchunks(Head, State#dets_cont.alloc) of
{error, Reason} ->
dets_utils:corrupt_reason(Head, Reason);
{finished, Bins} ->
{Head, {State#dets_cont{bin = eof}, Bins}};
{Bins, NewL} ->
{Head, {State#dets_cont{alloc = NewL}, Bins}}
end.
%% -> {NewHead, Result}
fdelete_all_objects(Head) when Head#head.fixed =:= false ->
case catch do_delete_all_objects(Head) of
{ok, NewHead} ->
start_auto_save_timer(NewHead),
{NewHead, ok};
{error, Reason} ->
dets_utils:corrupt_reason(Head, Reason)
end;
fdelete_all_objects(Head) ->
{Head, fixed}.
do_delete_all_objects(Head) ->
#head{fptr = Fd, name = Tab, filename = Fname, type = Type, keypos = Kp,
ram_file = Ram, auto_save = Auto, min_no_slots = MinSlots,
max_no_slots = MaxSlots, cache = Cache} = Head,
CacheSz = dets_utils:cache_size(Cache),
ok = dets_utils:truncate(Fd, Fname, bof),
(Head#head.mod):initiate_file(Fd, Tab, Fname, Type, Kp, MinSlots, MaxSlots,
Ram, CacheSz, Auto, true).
%% -> {NewHead, Reply}, Reply = ok | Error.
fdelete_key(Head, Keys) ->
do_delete(Head, Keys, delete_key).
%% -> {NewHead, Reply}, Reply = ok | badarg | Error.
fdelete_object(Head, Objects) ->
do_delete(Head, Objects, delete_object).
ffirst(H) ->
Ref = make_ref(),
case catch {Ref, ffirst1(H)} of
{Ref, {NH, R}} ->
{NH, {ok, R}};
{NH, R} when is_record(NH, head) ->
{NH, {error, R}}
end.
ffirst1(H) ->
check_safe_fixtable(H),
{NH, []} = write_cache(H),
ffirst(NH, 0).
ffirst(H, Slot) ->
case (H#head.mod):slot_objs(H, Slot) of
'$end_of_table' -> {H, '$end_of_table'};
[] -> ffirst(H, Slot+1);
[X|_] -> {H, element(H#head.keypos, X)}
end.
%% -> {NewHead, Reply}, Reply = ok | badarg | Error.
finsert(Head, Objects) ->
case catch update_cache(Head, Objects, insert) of
{NewHead, []} ->
{NewHead, ok};
{NewHead, _} = HeadError when is_record(NewHead, head) ->
HeadError
end.
%% -> {NewHead, Reply}, Reply = ok | badarg | Error.
finsert_new(Head, Objects) ->
KeyPos = Head#head.keypos,
case catch lists:map(fun(Obj) -> element(KeyPos, Obj) end, Objects) of
Keys when is_list(Keys) ->
case catch update_cache(Head, Keys, {lookup, nopid}) of
{Head1, PidObjs} when is_list(PidObjs) ->
case lists:all(fun({_P,OL}) -> OL =:= [] end, PidObjs) of
true ->
case catch update_cache(Head1, Objects, insert) of
{NewHead, []} ->
{NewHead, true};
{NewHead, Error} when is_record(NewHead, head) ->
{NewHead, Error}
end;
false=Reply ->
{Head1, Reply}
end;
{NewHead, _} = HeadError when is_record(NewHead, head) ->
HeadError
end;
_ ->
{Head, badarg}
end.
do_safe_fixtable(Head, Pid, true) ->
case Head#head.fixed of
false ->
link(Pid),
Fixed = {erlang:now(), [{Pid, 1}]},
Ftab = dets_utils:get_freelists(Head),
Head#head{fixed = Fixed, freelists = {Ftab, Ftab}};
{TimeStamp, Counters} ->
case lists:keysearch(Pid, 1, Counters) of
{value, {Pid, Counter}} -> % when Counter > 1
NewCounters = lists:keyreplace(Pid, 1, Counters,
{Pid, Counter+1}),
Head#head{fixed = {TimeStamp, NewCounters}};
false ->
link(Pid),
Fixed = {TimeStamp, [{Pid, 1} | Counters]},
Head#head{fixed = Fixed}
end
end;
do_safe_fixtable(Head, Pid, false) ->
remove_fix(Head, Pid, false).
remove_fix(Head, Pid, How) ->
case Head#head.fixed of
false ->
Head;
{TimeStamp, Counters} ->
case lists:keysearch(Pid, 1, Counters) of
%% How =:= close when Pid closes the table.
{value, {Pid, Counter}} when Counter =:= 1; How =:= close ->
unlink(Pid),
case lists:keydelete(Pid, 1, Counters) of
[] ->
check_growth(Head),
erlang:garbage_collect(),
Head#head{fixed = false,
freelists = dets_utils:get_freelists(Head)};
NewCounters ->
Head#head{fixed = {TimeStamp, NewCounters}}
end;
{value, {Pid, Counter}} ->
NewCounters = lists:keyreplace(Pid, 1, Counters,
{Pid, Counter-1}),
Head#head{fixed = {TimeStamp, NewCounters}};
false ->
Head
end
end.
do_stop(Head) ->
unlink_fixing_procs(Head),
fclose(Head).
unlink_fixing_procs(Head) ->
case Head#head.fixed of
false ->
Head;
{_, Counters} ->
lists:map(fun({Pid, _Counter}) -> unlink(Pid) end, Counters),
Head#head{fixed = false,
freelists = dets_utils:get_freelists(Head)}
end.
check_growth(#head{access = read}) ->
ok;
check_growth(Head) ->
NoThings = no_things(Head),
if
NoThings > Head#head.next ->
erlang:send_after(200, self(),
?DETS_CALL(self(), may_grow)); % Catch up.
true ->
ok
end.
finfo(H) ->
case catch write_cache(H) of
{H2, []} ->
Info = (catch [{type, H2#head.type},
{keypos, H2#head.keypos},
{size, H2#head.no_objects},
{file_size,
file_size(H2#head.fptr, H2#head.filename)},
{filename, H2#head.filename}]),
{H2, Info};
{H2, _} = HeadError when is_record(H2, head) ->
HeadError
end.
finfo(H, access) -> {H, H#head.access};
finfo(H, auto_save) -> {H, H#head.auto_save};
finfo(H, bchunk_format) ->
case catch write_cache(H) of
{H2, []} ->
case (H2#head.mod):table_parameters(H2) of
undefined = Undef ->
{H2, Undef};
Parms ->
{H2, term_to_binary(Parms)}
end;
{H2, _} = HeadError when is_record(H2, head) ->
HeadError
end;
finfo(H, delayed_write) -> % undocumented
{H, dets_utils:cache_size(H#head.cache)};
finfo(H, filename) -> {H, H#head.filename};
finfo(H, file_size) ->
case catch write_cache(H) of
{H2, []} ->
{H2, catch file_size(H#head.fptr, H#head.filename)};
{H2, _} = HeadError when is_record(H2, head) ->
HeadError
end;
finfo(H, fixed) ->
%% true if fixtable/2 has been called
{H, not (H#head.fixed =:= false)};
finfo(H, hash) -> {H, H#head.hash_bif};
finfo(H, keypos) -> {H, H#head.keypos};
finfo(H, memory) -> finfo(H, file_size);
finfo(H, no_objects) -> finfo(H, size);
finfo(H, no_keys) ->
case catch write_cache(H) of
{H2, []} ->
{H2, H2#head.no_keys};
{H2, _} = HeadError when is_record(H2, head) ->
HeadError
end;
finfo(H, no_slots) -> {H, (H#head.mod):no_slots(H)};
finfo(H, pid) -> {H, self()};
finfo(H, ram_file) -> {H, H#head.ram_file};
finfo(H, safe_fixed) -> {H, H#head.fixed};
finfo(H, size) ->
case catch write_cache(H) of
{H2, []} ->
{H2, H2#head.no_objects};
{H2, _} = HeadError when is_record(H2, head) ->
HeadError
end;
finfo(H, type) -> {H, H#head.type};
finfo(H, version) -> {H, H#head.version};
finfo(H, _) -> {H, undefined}.
file_size(Fd, FileName) ->
{ok, Pos} = dets_utils:position(Fd, FileName, eof),
Pos.
test_bchunk_format(_Head, undefined) ->
false;
test_bchunk_format(Head, _Term) when Head#head.version =:= 8 ->
false;
test_bchunk_format(Head, Term) ->
dets_v9:try_bchunk_header(Term, Head) =/= not_ok.
do_open_file([Fname, Verbose], Parent, Server, Ref) ->
case catch fopen2(Fname, Ref) of
{error, _Reason} = Error ->
err(Error);
{ok, Head} ->
maybe_put(verbose, Verbose),
{ok, Head#head{parent = Parent, server = Server}};
{'EXIT', _Reason} = Error ->
Error;
Bad ->
error_logger:format
("** dets: Bug was found in open_file/1, reply was ~w.~n",
[Bad]),
{error, {dets_bug, Fname, Bad}}
end;
do_open_file([Tab, OpenArgs, Verb], Parent, Server, Ref) ->
case catch fopen3(Tab, OpenArgs) of
{error, {tooshort, _}} ->
file:delete(OpenArgs#open_args.file),
do_open_file([Tab, OpenArgs, Verb], Parent, Server, Ref);
{error, _Reason} = Error ->
err(Error);
{ok, Head} ->
maybe_put(verbose, Verb),
{ok, Head#head{parent = Parent, server = Server}};
{'EXIT', _Reason} = Error ->
Error;
Bad ->
error_logger:format
("** dets: Bug was found in open_file/2, arguments were~n"
"** dets: ~w and reply was ~w.~n",
[OpenArgs, Bad]),
{error, {dets_bug, Tab, {open_file, OpenArgs}, Bad}}
end.
maybe_put(_, undefined) ->
ignore;
maybe_put(K, V) ->
put(K, V).
%% -> {Head, Result}, Result = ok | Error | {thrown, Error} | badarg
finit(Head, InitFun, _Format, _NoSlots) when Head#head.access =:= read ->
_ = (catch InitFun(close)),
{Head, {error, {access_mode, Head#head.filename}}};
finit(Head, InitFun, _Format, _NoSlots) when Head#head.fixed =/= false ->
_ = (catch InitFun(close)),
{Head, {error, {fixed_table, Head#head.name}}};
finit(Head, InitFun, Format, NoSlots) ->
case catch do_finit(Head, InitFun, Format, NoSlots) of
{ok, NewHead} ->
check_growth(NewHead),
start_auto_save_timer(NewHead),
{NewHead, ok};
badarg ->
{Head, badarg};
Error ->
dets_utils:corrupt(Head, Error)
end.
%% -> {ok, NewHead} | throw(badarg) | throw(Error)
do_finit(Head, Init, Format, NoSlots) ->
#head{fptr = Fd, type = Type, keypos = Kp, auto_save = Auto,
cache = Cache, filename = Fname, ram_file = Ram,
min_no_slots = MinSlots0, max_no_slots = MaxSlots,
name = Tab, update_mode = UpdateMode, mod = HMod} = Head,
CacheSz = dets_utils:cache_size(Cache),
{How, Head1} =
case Format of
term when is_integer(NoSlots), NoSlots > MaxSlots ->
throw(badarg);
term ->
MinSlots = choose_no_slots(NoSlots, MinSlots0),
if
UpdateMode =:= new_dirty, MinSlots =:= MinSlots0 ->
{general_init, Head};
true ->
ok = dets_utils:truncate(Fd, Fname, bof),
{ok, H} = HMod:initiate_file(Fd, Tab, Fname, Type, Kp,
MinSlots, MaxSlots, Ram,
CacheSz, Auto, false),
{general_init, H}
end;
bchunk ->
ok = dets_utils:truncate(Fd, Fname, bof),
{bchunk_init, Head}
end,
case How of
bchunk_init ->
case HMod:bchunk_init(Head1, Init) of
{ok, NewHead} ->
{ok, NewHead#head{update_mode = dirty}};
Error ->
Error
end;
general_init ->
Cntrs = ets:new(dets_init, []),
Input = HMod:bulk_input(Head1, Init, Cntrs),
SlotNumbers = {Head1#head.min_no_slots, bulk_init, MaxSlots},
{Reply, SizeData} =
do_sort(Head1, SlotNumbers, Input, Cntrs, Fname, not_used),
Bulk = true,
case Reply of
{ok, NoDups, H1} ->
fsck_copy(SizeData, H1, Bulk, NoDups);
Else ->
close_files(Bulk, SizeData, Head1),
Else
end
end.
%% -> {NewHead, [LookedUpObject]} | {NewHead, Error}
flookup_keys(Head, Keys) ->
case catch update_cache(Head, Keys, {lookup, nopid}) of
{NewHead, [{_NoPid,Objs}]} ->
{NewHead, Objs};
{NewHead, L} when is_list(L) ->
{NewHead, lists:flatmap(fun({_Pid,OL}) -> OL end, L)};
{NewHead, _} = HeadError when is_record(NewHead, head) ->
HeadError
end.
%% -> {NewHead, Result}
fmatch_init(Head, C) ->
case scan(Head, C) of
{scan_error, Reason} ->
dets_utils:corrupt_reason(Head, Reason);
{Ts, NC} ->
{Head, {cont, {Ts, NC}}}
end.
%% -> {NewHead, Result}
fmatch(Head, MP, Spec, N) ->
KeyPos = Head#head.keypos,
case find_all_keys(Spec, KeyPos, []) of
[] ->
%% Complete match
case catch write_cache(Head) of
{NewHead, []} ->
C0 = init_scan(NewHead, N),
{NewHead, {cont, C0#dets_cont{match_program = MP}}};
{NewHead, _} = HeadError when is_record(NewHead, head) ->
HeadError
end;
List ->
Keys = lists:usort(List),
{NewHead, Reply} = flookup_keys(Head, Keys),
case Reply of
Objs when is_list(Objs) ->
MatchingObjs = ets:match_spec_run(Objs, MP),
{NewHead, {done, MatchingObjs}};
Error ->
{NewHead, Error}
end
end.
find_all_keys([], _, Ks) ->
Ks;
find_all_keys([{H,_,_} | T], KeyPos, Ks) when is_tuple(H) ->
case tuple_size(H) of
Enough when Enough >= KeyPos ->
Key = element(KeyPos, H),
case contains_variable(Key) of
true ->
[];
false ->
find_all_keys(T, KeyPos, [Key | Ks])
end;
_ ->
find_all_keys(T, KeyPos, Ks)
end;
find_all_keys(_, _, _) ->
[].
contains_variable('_') ->
true;
contains_variable(A) when is_atom(A) ->
case atom_to_list(A) of
[$$ | T] ->
case (catch list_to_integer(T)) of
{'EXIT', _} ->
false;
_ ->
true
end;
_ ->
false
end;
contains_variable(T) when is_tuple(T) ->
contains_variable(tuple_to_list(T));
contains_variable([]) ->
false;
contains_variable([H|T]) ->
case contains_variable(H) of
true ->
true;
false ->
contains_variable(T)
end;
contains_variable(_) ->
false.
%% -> {NewHead, Res}
fmatch_delete_init(Head, MP, Spec) ->
KeyPos = Head#head.keypos,
case catch
case find_all_keys(Spec, KeyPos, []) of
[] ->
do_fmatch_delete_var_keys(Head, MP, Spec);
List ->
Keys = lists:usort(List),
do_fmatch_constant_keys(Head, Keys, MP)
end of
{NewHead, _} = Reply when is_record(NewHead, head) ->
Reply
end.
%% A note: If deleted objects reside in a bucket with other objects
%% that are not deleted, the bucket is moved. If the address of the
%% moved bucket is greater than original bucket address the kept
%% objects will be read once again later on.
%% -> {NewHead, Res}
fmatch_delete(Head, C) ->
case scan(Head, C) of
{scan_error, Reason} ->
dets_utils:corrupt_reason(Head, Reason);
{[], _} ->
{Head, {done, 0}};
{RTs, NC} ->
MP = C#dets_cont.match_program,
case catch filter_binary_terms(RTs, MP, []) of
{'EXIT', _} ->
Bad = dets_utils:bad_object(fmatch_delete, RTs),
dets_utils:corrupt_reason(Head, Bad);
Terms ->
do_fmatch_delete(Head, Terms, NC)
end
end.
do_fmatch_delete_var_keys(Head, _MP, ?PATTERN_TO_TRUE_MATCH_SPEC('_'))
when Head#head.fixed =:= false ->
%% Handle the case where the file is emptied efficiently.
%% Empty the cache just to get the number of objects right.
{Head1, []} = write_cache(Head),
N = Head1#head.no_objects,
case fdelete_all_objects(Head1) of
{NewHead, ok} ->
{NewHead, {done, N}};
Reply ->
Reply
end;
do_fmatch_delete_var_keys(Head, MP, _Spec) ->
{NewHead, []} = write_cache(Head),
C0 = init_scan(NewHead, default),
{NewHead, {cont, C0#dets_cont{match_program = MP}, 0}}.
do_fmatch_constant_keys(Head, Keys, MP) ->
case flookup_keys(Head, Keys) of
{NewHead, ReadTerms} when is_list(ReadTerms) ->
Terms = filter_terms(ReadTerms, MP, []),
do_fmatch_delete(NewHead, Terms, fixed);
Reply ->
Reply
end.
filter_binary_terms([Bin | Bins], MP, L) ->
Term = binary_to_term(Bin),
case ets:match_spec_run([Term], MP) of
[true] ->
filter_binary_terms(Bins, MP, [Term | L]);
_ ->
filter_binary_terms(Bins, MP, L)
end;
filter_binary_terms([], _MP, L) ->
L.
filter_terms([Term | Terms], MP, L) ->
case ets:match_spec_run([Term], MP) of
[true] ->
filter_terms(Terms, MP, [Term | L]);
_ ->
filter_terms(Terms, MP, L)
end;
filter_terms([], _MP, L) ->
L.
do_fmatch_delete(Head, Terms, What) ->
N = length(Terms),
case do_delete(Head, Terms, delete_object) of
{NewHead, ok} when What =:= fixed ->
{NewHead, {done, N}};
{NewHead, ok} ->
{NewHead, {cont, What, N}};
Reply ->
Reply
end.
do_delete(Head, Things, What) ->
case catch update_cache(Head, Things, What) of
{NewHead, []} ->
{NewHead, ok};
{NewHead, _} = HeadError when is_record(NewHead, head) ->
HeadError
end.
fmember(Head, Key) ->
case catch begin
{Head2, [{_NoPid,Objs}]} =
update_cache(Head, [Key], {lookup, nopid}),
{Head2, Objs =/= []}
end of
{NewHead, _} = Reply when is_record(NewHead, head) ->
Reply
end.
fnext(Head, Key) ->
Slot = (Head#head.mod):db_hash(Key, Head),
Ref = make_ref(),
case catch {Ref, fnext(Head, Key, Slot)} of
{Ref, {H, R}} ->
{H, {ok, R}};
{NewHead, _} = HeadError when is_record(NewHead, head) ->
HeadError
end.
fnext(H, Key, Slot) ->
{NH, []} = write_cache(H),
case (H#head.mod):slot_objs(NH, Slot) of
'$end_of_table' -> {NH, '$end_of_table'};
L -> fnext_search(NH, Key, Slot, L)
end.
fnext_search(H, K, Slot, L) ->
Kp = H#head.keypos,
case beyond_key(K, Kp, L) of
[] -> fnext_slot(H, K, Slot+1);
L2 -> {H, element(H#head.keypos, hd(L2))}
end.
%% We've got to continue to search for the next key in the next slot
fnext_slot(H, K, Slot) ->
case (H#head.mod):slot_objs(H, Slot) of
'$end_of_table' -> {H, '$end_of_table'};
[] -> fnext_slot(H, K, Slot+1);
L -> {H, element(H#head.keypos, hd(L))}
end.
beyond_key(_K, _Kp, []) -> [];
beyond_key(K, Kp, [H|T]) ->
case dets_utils:cmp(element(Kp, H), K) of
0 -> beyond_key2(K, Kp, T);
_ -> beyond_key(K, Kp, T)
end.
beyond_key2(_K, _Kp, []) -> [];
beyond_key2(K, Kp, [H|T]=L) ->
case dets_utils:cmp(element(Kp, H), K) of
0 -> beyond_key2(K, Kp, T);
_ -> L
end.
%% Open an already existing file, no arguments
%% -> {ok, head()} | throw(Error)
fopen2(Fname, Tab) ->
case file:read_file_info(Fname) of
{ok, _} ->
Acc = read_write,
Ram = false,
%% Fd is not always closed upon error, but exit is soon called.
{ok, Fd, FH} = read_file_header(Fname, Acc, Ram),
Mod = FH#fileheader.mod,
case Mod:check_file_header(FH, Fd) of
{error, not_closed} ->
io:format(user,"dets: file ~p not properly closed, "
"repairing ...~n", [Fname]),
Version = default,
case fsck(Fd, Tab, Fname, FH, default, default, Version) of
ok ->
fopen2(Fname, Tab);
Error ->
throw(Error)
end;
{ok, Head, ExtraInfo} ->
open_final(Head, Fname, Acc, Ram, ?DEFAULT_CACHE,
Tab, ExtraInfo, false);
{error, Reason} ->
throw({error, {Reason, Fname}})
end;
Error ->
dets_utils:file_error(Fname, Error)
end.
%% Open and possibly create and initialize a file
%% -> {ok, head()} | throw(Error)
fopen3(Tab, OpenArgs) ->
FileName = OpenArgs#open_args.file,
case file:read_file_info(FileName) of
{ok, _} ->
fopen_existing_file(Tab, OpenArgs);
Error when OpenArgs#open_args.access =:= read ->
dets_utils:file_error(FileName, Error);
_Error ->
fopen_init_file(Tab, OpenArgs)
end.
fopen_existing_file(Tab, OpenArgs) ->
#open_args{file = Fname, type = Type, keypos = Kp, repair = Rep,
min_no_slots = MinSlots, max_no_slots = MaxSlots,
ram_file = Ram, delayed_write = CacheSz, auto_save =
Auto, access = Acc, version = Version, debug = Debug} =
OpenArgs,
%% Fd is not always closed upon error, but exit is soon called.
{ok, Fd, FH} = read_file_header(Fname, Acc, Ram),
V9 = (Version =:= 9) or (Version =:= default),
MinF = (MinSlots =:= default) or (MinSlots =:= FH#fileheader.min_no_slots),
MaxF = (MaxSlots =:= default) or (MaxSlots =:= FH#fileheader.max_no_slots),
Do = case (FH#fileheader.mod):check_file_header(FH, Fd) of
{ok, Head, true} when Rep =:= force, Acc =:= read_write,
FH#fileheader.version =:= 9,
FH#fileheader.no_colls =/= undefined,
MinF, MaxF, V9 ->
{compact, Head};
{ok, _Head, _Extra} when Rep =:= force, Acc =:= read ->
throw({error, {access_mode, Fname}});
{ok, Head, need_compacting} when Acc =:= read ->
{final, Head, true}; % Version 8 only.
{ok, _Head, need_compacting} when Rep =:= true ->
%% The file needs to be compacted due to a very big
%% and fragmented free_list. Version 8 only.
M = " is now compacted ...",
{repair, M};
{ok, _Head, _Extra} when Rep =:= force ->
M = ", repair forced.",
{repair, M};
{ok, Head, ExtraInfo} ->
{final, Head, ExtraInfo};
{error, not_closed} when Rep =:= force, Acc =:= read_write ->
M = ", repair forced.",
{repair, M};
{error, not_closed} when Rep =:= true, Acc =:= read_write ->
M = " not properly closed, repairing ...",
{repair, M};
{error, not_closed} when Rep =:= false ->
throw({error, {needs_repair, Fname}});
{error, version_bump} when Rep =:= true, Acc =:= read_write ->
%% Version 8 only
M = " old version, upgrading ...",
{repair, M};
{error, Reason} ->
throw({error, {Reason, Fname}})
end,
case Do of
_ when FH#fileheader.type =/= Type ->
throw({error, {type_mismatch, Fname}});
_ when FH#fileheader.keypos =/= Kp ->
throw({error, {keypos_mismatch, Fname}});
{compact, SourceHead} ->
io:format(user, "dets: file ~p is now compacted ...~n", [Fname]),
{ok, NewSourceHead} = open_final(SourceHead, Fname, read, false,
?DEFAULT_CACHE, Tab, true,
Debug),
case catch compact(NewSourceHead) of
ok ->
erlang:garbage_collect(),
fopen3(Tab, OpenArgs#open_args{repair = false});
_Err ->
_ = file:close(Fd),
dets_utils:stop_disk_map(),
io:format(user, "dets: compaction of file ~p failed, "
"now repairing ...~n", [Fname]),
{ok, Fd2, _FH} = read_file_header(Fname, Acc, Ram),
do_repair(Fd2, Tab, Fname, FH, MinSlots, MaxSlots,
Version, OpenArgs)
end;
{repair, Mess} ->
io:format(user, "dets: file ~p~s~n", [Fname, Mess]),
do_repair(Fd, Tab, Fname, FH, MinSlots, MaxSlots,
Version, OpenArgs);
_ when FH#fileheader.version =/= Version, Version =/= default ->
throw({error, {version_mismatch, Fname}});
{final, H, EI} ->
H1 = H#head{auto_save = Auto},
open_final(H1, Fname, Acc, Ram, CacheSz, Tab, EI, Debug)
end.
do_repair(Fd, Tab, Fname, FH, MinSlots, MaxSlots, Version, OpenArgs) ->
case fsck(Fd, Tab, Fname, FH, MinSlots, MaxSlots, Version) of
ok ->
%% No need to update 'version'.
erlang:garbage_collect(),
fopen3(Tab, OpenArgs#open_args{repair = false});
Error ->
throw(Error)
end.
%% -> {ok, head()} | throw(Error)
open_final(Head, Fname, Acc, Ram, CacheSz, Tab, ExtraInfo, Debug) ->
Head1 = Head#head{access = Acc,
ram_file = Ram,
filename = Fname,
name = Tab,
cache = dets_utils:new_cache(CacheSz)},
init_disk_map(Head1#head.version, Tab, Debug),
Mod = Head#head.mod,
Mod:cache_segps(Head1#head.fptr, Fname, Head1#head.next),
Ftab = Mod:init_freelist(Head1, ExtraInfo),
check_growth(Head1),
NewHead = Head1#head{freelists = Ftab},
{ok, NewHead}.
%% -> {ok, head()} | throw(Error)
fopen_init_file(Tab, OpenArgs) ->
#open_args{file = Fname, type = Type, keypos = Kp,
min_no_slots = MinSlotsArg, max_no_slots = MaxSlotsArg,
ram_file = Ram, delayed_write = CacheSz, auto_save = Auto,
version = UseVersion, debug = Debug} = OpenArgs,
MinSlots = choose_no_slots(MinSlotsArg, ?DEFAULT_MIN_NO_SLOTS),
MaxSlots = choose_no_slots(MaxSlotsArg, ?DEFAULT_MAX_NO_SLOTS),
FileSpec = if
Ram -> [];
true -> Fname
end,
{ok, Fd} = dets_utils:open(FileSpec, open_args(read_write, Ram)),
Version = if
UseVersion =:= default ->
case os:getenv("DETS_USE_FILE_FORMAT") of
"8" -> 8;
_ -> 9
end;
true ->
UseVersion
end,
Mod = version2module(Version),
%% No need to truncate an empty file.
init_disk_map(Version, Tab, Debug),
case catch Mod:initiate_file(Fd, Tab, Fname, Type, Kp, MinSlots, MaxSlots,
Ram, CacheSz, Auto, true) of
{error, Reason} when Ram ->
file:close(Fd),
throw({error, Reason});
{error, Reason} ->
file:close(Fd),
file:delete(Fname),
throw({error, Reason});
{ok, Head} ->
start_auto_save_timer(Head),
%% init_table does not need to truncate and write header
{ok, Head#head{update_mode = new_dirty}}
end.
%% Debug.
init_disk_map(9, Name, Debug) ->
case Debug orelse dets_utils:debug_mode() of
true ->
dets_utils:init_disk_map(Name);
false ->
ok
end;
init_disk_map(_Version, _Name, _Debug) ->
ok.
open_args(Access, RamFile) ->
A1 = case Access of
read -> [];
read_write -> [write]
end,
A2 = case RamFile of
true -> [ram];
false -> [raw]
end,
A1 ++ A2 ++ [binary, read].
version2module(V) when V =< 8 -> dets_v8;
version2module(9) -> dets_v9.
module2version(dets_v8) -> 8;
module2version(dets_v9) -> 9;
module2version(not_used) -> 9.
%% -> ok | throw(Error)
%% For version 9 tables only.
compact(SourceHead) ->
#head{name = Tab, filename = Fname, fptr = SFd, type = Type, keypos = Kp,
ram_file = Ram, auto_save = Auto} = SourceHead,
Tmp = tempfile(Fname),
TblParms = dets_v9:table_parameters(SourceHead),
{ok, Fd} = dets_utils:open(Tmp, open_args(read_write, false)),
CacheSz = ?DEFAULT_CACHE,
%% It is normally not possible to have two open tables in the same
%% process since the process dictionary is used for caching
%% segment pointers, but here is works anyway--when reading a file
%% serially the pointers to not need to be used.
Head = case catch dets_v9:prep_table_copy(Fd, Tab, Tmp, Type, Kp, Ram,
CacheSz, Auto, TblParms) of
{ok, H} ->
H;
Error ->
file:close(Fd),
file:delete(Tmp),
throw(Error)
end,
case dets_v9:compact_init(SourceHead, Head, TblParms) of
{ok, NewHead} ->
R = case fclose(NewHead) of
ok ->
ok = file:close(SFd),
%% Save (rename) Fname first?
dets_utils:rename(Tmp, Fname);
E ->
E
end,
if
R =:= ok -> ok;
true ->
file:delete(Tmp),
throw(R)
end;
Err ->
file:close(Fd),
file:delete(Tmp),
throw(Err)
end.
%% -> ok | Error
%% Closes Fd.
fsck(Fd, Tab, Fname, FH, MinSlotsArg, MaxSlotsArg, Version) ->
%% MinSlots and MaxSlots are the option values.
#fileheader{min_no_slots = MinSlotsFile,
max_no_slots = MaxSlotsFile} = FH,
EstNoSlots0 = file_no_things(FH),
MinSlots = choose_no_slots(MinSlotsArg, MinSlotsFile),
MaxSlots = choose_no_slots(MaxSlotsArg, MaxSlotsFile),
EstNoSlots = erlang:min(MaxSlots, erlang:max(MinSlots, EstNoSlots0)),
SlotNumbers = {MinSlots, EstNoSlots, MaxSlots},
%% When repairing: We first try and sort on slots using MinSlots.
%% If the number of objects (keys) turns out to be significantly
%% different from NoSlots, we try again with the correct number of
%% objects (keys).
case fsck_try(Fd, Tab, FH, Fname, SlotNumbers, Version) of
{try_again, BetterNoSlots} ->
BetterSlotNumbers = {MinSlots, BetterNoSlots, MaxSlots},
case fsck_try(Fd, Tab, FH, Fname, BetterSlotNumbers, Version) of
{try_again, _} ->
file:close(Fd),
{error, {cannot_repair, Fname}};
Else ->
Else
end;
Else ->
Else
end.
choose_no_slots(default, NoSlots) -> NoSlots;
choose_no_slots(NoSlots, _) -> NoSlots.
%% -> ok | {try_again, integer()} | Error
%% Closes Fd unless {try_again, _} is returned.
%% Initiating a table using a fun and repairing (or converting) a
%% file are completely different things, but nevertheless the same
%% method is used in both cases...
fsck_try(Fd, Tab, FH, Fname, SlotNumbers, Version) ->
Tmp = tempfile(Fname),
#fileheader{type = Type, keypos = KeyPos} = FH,
{_MinSlots, EstNoSlots, MaxSlots} = SlotNumbers,
OpenArgs = #open_args{file = Tmp, type = Type, keypos = KeyPos,
repair = false, min_no_slots = EstNoSlots,
max_no_slots = MaxSlots,
ram_file = false, delayed_write = ?DEFAULT_CACHE,
auto_save = infinity, access = read_write,
version = Version, debug = false},
case catch fopen3(Tab, OpenArgs) of
{ok, Head} ->
case fsck_try_est(Head, Fd, Fname, SlotNumbers, FH) of
{ok, NewHead} ->
R = case fclose(NewHead) of
ok ->
%% Save (rename) Fname first?
dets_utils:rename(Tmp, Fname);
Error ->
Error
end,
if
R =:= ok -> ok;
true ->
file:delete(Tmp),
R
end;
TryAgainOrError ->
file:delete(Tmp),
TryAgainOrError
end;
Error ->
file:close(Fd),
Error
end.
tempfile(Fname) ->
Tmp = lists:concat([Fname, ".TMP"]),
case file:delete(Tmp) of
{error, eacces} -> % 'dets_process_died' happened anyway... (W-nd-ws)
timer:sleep(5000),
file:delete(Tmp);
_ ->
ok
end,
Tmp.
%% -> {ok, NewHead} | {try_again, integer()} | Error
fsck_try_est(Head, Fd, Fname, SlotNumbers, FH) ->
%% Mod is the module to use for reading input when repairing.
Mod = FH#fileheader.mod,
Cntrs = ets:new(dets_repair, []),
Input = Mod:fsck_input(Head, Fd, Cntrs, FH),
{Reply, SizeData} = do_sort(Head, SlotNumbers, Input, Cntrs, Fname, Mod),
Bulk = false,
case Reply of
{ok, NoDups, H1} ->
file:close(Fd),
fsck_copy(SizeData, H1, Bulk, NoDups);
{try_again, _} = Return ->
close_files(Bulk, SizeData, Head),
Return;
Else ->
file:close(Fd),
close_files(Bulk, SizeData, Head),
Else
end.
do_sort(Head, SlotNumbers, Input, Cntrs, Fname, Mod) ->
OldV = module2version(Mod),
%% output_objs/4 replaces {LogSize,NoObjects} in Cntrs by
%% {LogSize,Position,Data,NoObjects | NoCollections}.
%% Data = {FileName,FileDescriptor} | [object()]
%% For small tables Data may be a list of objects which is more
%% efficient since no temporary files are created.
Output = (Head#head.mod):output_objs(OldV, Head, SlotNumbers, Cntrs),
TmpDir = filename:dirname(Fname),
Reply = (catch file_sorter:sort(Input, Output,
[{format, binary},{tmpdir, TmpDir}])),
L = ets:tab2list(Cntrs),
ets:delete(Cntrs),
{Reply, lists:reverse(lists:keysort(1, L))}.
fsck_copy([{_LogSz, Pos, Bins, _NoObjects} | SizeData], Head, _Bulk, NoDups)
when is_list(Bins) ->
true = NoDups =:= 0,
PWs = [{Pos,Bins} | lists:map(fun({_, P, B, _}) -> {P, B} end, SizeData)],
#head{fptr = Fd, filename = FileName} = Head,
dets_utils:pwrite(Fd, FileName, PWs),
{ok, Head#head{update_mode = dirty}};
fsck_copy(SizeData, Head, Bulk, NoDups) ->
catch fsck_copy1(SizeData, Head, Bulk, NoDups).
fsck_copy1([SzData | L], Head, Bulk, NoDups) ->
Out = Head#head.fptr,
{LogSz, Pos, {FileName, Fd}, NoObjects} = SzData,
Size = if NoObjects =:= 0 -> 0; true -> ?POW(LogSz-1) end,
ExpectedSize = Size * NoObjects,
close_tmp(Fd),
case file:position(Out, Pos) of
{ok, Pos} -> ok;
PError -> dets_utils:file_error(FileName, PError)
end,
{ok, Pos} = file:position(Out, Pos),
CR = file:copy({FileName, [raw,binary]}, Out),
file:delete(FileName),
case CR of
{ok, Copied} when Copied =:= ExpectedSize;
NoObjects =:= 0 -> % the segments
fsck_copy1(L, Head, Bulk, NoDups);
{ok, Copied} when Bulk, Head#head.version =:= 8 ->
NoZeros = ExpectedSize - Copied,
Dups = NoZeros div Size,
Addr = Pos+Copied,
NewHead = free_n_objects(Head, Addr, Size-1, NoDups),
NewNoDups = NoDups - Dups,
fsck_copy1(L, NewHead, Bulk, NewNoDups);
{ok, _Copied} -> % should never happen
close_files(Bulk, L, Head),
Reason = if Bulk -> initialization_failed;
true -> repair_failed end,
{error, {Reason, Head#head.filename}};
FError ->
close_files(Bulk, L, Head),
dets_utils:file_error(FileName, FError)
end;
fsck_copy1([], Head, _Bulk, NoDups) when NoDups =/= 0 ->
{error, {initialization_failed, Head#head.filename}};
fsck_copy1([], Head, _Bulk, _NoDups) ->
{ok, Head#head{update_mode = dirty}}.
free_n_objects(Head, _Addr, _Size, 0) ->
Head;
free_n_objects(Head, Addr, Size, N) ->
{NewHead, _} = dets_utils:free(Head, Addr, Size),
NewAddr = Addr + Size + 1,
free_n_objects(NewHead, NewAddr, Size, N-1).
close_files(false, SizeData, Head) ->
file:close(Head#head.fptr),
close_files(true, SizeData, Head);
close_files(true, SizeData, _Head) ->
Fun = fun({_Size, _Pos, {FileName, Fd}, _No}) ->
close_tmp(Fd),
file:delete(FileName);
(_) ->
ok
end,
lists:foreach(Fun, SizeData).
close_tmp(Fd) ->
file:close(Fd).
fslot(H, Slot) ->
case catch begin
{NH, []} = write_cache(H),
Objs = (NH#head.mod):slot_objs(NH, Slot),
{NH, Objs}
end of
{NewHead, _Objects} = Reply when is_record(NewHead, head) ->
Reply
end.
do_update_counter(Head, _Key, _Incr) when Head#head.type =/= set ->
{Head, badarg};
do_update_counter(Head, Key, Incr) ->
case flookup_keys(Head, [Key]) of
{H1, [O]} ->
Kp = H1#head.keypos,
case catch try_update_tuple(O, Kp, Incr) of
{'EXIT', _} ->
{H1, badarg};
{New, Term} ->
case finsert(H1, [Term]) of
{H2, ok} ->
{H2, New};
Reply ->
Reply
end
end;
{H1, []} ->
{H1, badarg};
HeadError ->
HeadError
end.
try_update_tuple(O, _Kp, {Pos, Incr}) ->
try_update_tuple2(O, Pos, Incr);
try_update_tuple(O, Kp, Incr) ->
try_update_tuple2(O, Kp+1, Incr).
try_update_tuple2(O, Pos, Incr) ->
New = element(Pos, O) + Incr,
{New, setelement(Pos, O, New)}.
set_verbose(true) ->
put(verbose, yes);
set_verbose(_) ->
erase(verbose).
where_is_object(Head, Object) ->
Keypos = Head#head.keypos,
case check_objects([Object], Keypos) of
true ->
case catch write_cache(Head) of
{NewHead, []} ->
{NewHead, (Head#head.mod):find_object(NewHead, Object)};
{NewHead, _} = HeadError when is_record(NewHead, head) ->
HeadError
end;
false ->
{Head, badarg}
end.
check_objects([T | Ts], Kp) when tuple_size(T) >= Kp ->
check_objects(Ts, Kp);
check_objects(L, _Kp) ->
L =:= [].
no_things(Head) when Head#head.no_keys =:= undefined ->
Head#head.no_objects;
no_things(Head) ->
Head#head.no_keys.
file_no_things(FH) when FH#fileheader.no_keys =:= undefined ->
FH#fileheader.no_objects;
file_no_things(FH) ->
FH#fileheader.no_keys.
%%% The write cache is list of {Key, [Item]} where Item is one of
%%% {Seq, delete_key}, {Seq, {lookup,Pid}}, {Seq, {delete_object,object()}},
%%% or {Seq, {insert,object()}}. Seq is a number that increases
%%% monotonically for each item put in the cache. The purpose is to
%%% make sure that items are sorted correctly. Sequences of delete and
%%% insert operations are inserted in the cache without doing any file
%%% operations. When the cache is considered full, a lookup operation
%%% is requested, or after some delay, the contents of the cache are
%%% written to the file, and the cache emptied.
%%%
%%% Data is not allowed to linger more than 'delay' milliseconds in
%%% the write cache. A delayed_write message is received when some
%%% datum has become too old. If 'wrtime' is equal to 'undefined',
%%% then the cache is empty and no such delayed_write message has been
%%% scheduled. Otherwise there is a delayed_write message scheduled,
%%% and the value of 'wrtime' is the time when the cache was last
%%% written, or when it was first updated after the cache was last
%%% written.
update_cache(Head, KeysOrObjects, What) ->
{Head1, LU, PwriteList} = update_cache(Head, [{What,KeysOrObjects}]),
{NewHead, ok} = dets_utils:pwrite(Head1, PwriteList),
{NewHead, LU}.
%% -> {NewHead, [object()], pwrite_list()} | throw({Head, Error})
update_cache(Head, ToAdd) ->
Cache = Head#head.cache,
#cache{cache = C, csize = Size0, inserts = Ins} = Cache,
NewSize = Size0 + erlang:external_size(ToAdd),
%% The size is used as a sequence number here; it increases monotonically.
{NewC, NewIns, Lookup, Found} =
cache_binary(Head, ToAdd, C, Size0, Ins, false, []),
NewCache = Cache#cache{cache = NewC, csize = NewSize, inserts = NewIns},
Head1 = Head#head{cache = NewCache},
if
Lookup; NewSize >= Cache#cache.tsize ->
%% The cache is considered full, or some lookup.
{NewHead, LU, PwriteList} = (Head#head.mod):write_cache(Head1),
{NewHead, Found ++ LU, PwriteList};
NewC =:= [] ->
{Head1, Found, []};
Cache#cache.wrtime =:= undefined ->
%% Empty cache. Schedule a delayed write.
Now = now(), Me = self(),
Call = ?DETS_CALL(Me, {delayed_write, Now}),
erlang:send_after(Cache#cache.delay, Me, Call),
{Head1#head{cache = NewCache#cache{wrtime = Now}}, Found, []};
Size0 =:= 0 ->
%% Empty cache that has been written after the
%% currently scheduled delayed write.
{Head1#head{cache = NewCache#cache{wrtime = now()}}, Found, []};
true ->
%% Cache is not empty, delayed write has been scheduled.
{Head1, Found, []}
end.
cache_binary(Head, [{Q,Os} | L], C, Seq, Ins, Lu,F) when Q =:= delete_object ->
cache_obj_op(Head, L, C, Seq, Ins, Lu, F, Os, Head#head.keypos, Q);
cache_binary(Head, [{Q,Os} | L], C, Seq, Ins, Lu, F) when Q =:= insert ->
NewIns = Ins + length(Os),
cache_obj_op(Head, L, C, Seq, NewIns, Lu, F, Os, Head#head.keypos, Q);
cache_binary(Head, [{Q,Ks} | L], C, Seq, Ins, Lu, F) when Q =:= delete_key ->
cache_key_op(Head, L, C, Seq, Ins, Lu, F, Ks, Q);
cache_binary(Head, [{Q,Ks} | L], C, Seq, Ins, _Lu, F) when C =:= [] -> % lookup
cache_key_op(Head, L, C, Seq, Ins, true, F, Ks, Q);
cache_binary(Head, [{Q,Ks} | L], C, Seq, Ins, Lu, F) -> % lookup
case dets_utils:cache_lookup(Head#head.type, Ks, C, []) of
false ->
cache_key_op(Head, L, C, Seq, Ins, true, F, Ks, Q);
Found ->
{lookup,Pid} = Q,
cache_binary(Head, L, C, Seq, Ins, Lu, [{Pid,Found} | F])
end;
cache_binary(_Head, [], C, _Seq, Ins, Lu, F) ->
{C, Ins, Lu, F}.
cache_key_op(Head, L, C, Seq, Ins, Lu, F, [K | Ks], Q) ->
E = {K, {Seq, Q}},
cache_key_op(Head, L, [E | C], Seq+1, Ins, Lu, F, Ks, Q);
cache_key_op(Head, L, C, Seq, Ins, Lu, F, [], _Q) ->
cache_binary(Head, L, C, Seq, Ins, Lu, F).
cache_obj_op(Head, L, C, Seq, Ins, Lu, F, [O | Os], Kp, Q) ->
E = {element(Kp, O), {Seq, {Q, O}}},
cache_obj_op(Head, L, [E | C], Seq+1, Ins, Lu, F, Os, Kp, Q);
cache_obj_op(Head, L, C, Seq, Ins, Lu, F, [], _Kp, _Q) ->
cache_binary(Head, L, C, Seq, Ins, Lu, F).
%% Called after some delay.
%% -> NewHead
delayed_write(Head, WrTime) ->
Cache = Head#head.cache,
LastWrTime = Cache#cache.wrtime,
if
LastWrTime =:= WrTime ->
%% The cache was not emptied during the last delay.
case catch write_cache(Head) of
{Head2, []} ->
NewCache = (Head2#head.cache)#cache{wrtime = undefined},
Head2#head{cache = NewCache};
{NewHead, _Error} -> % Head.update_mode has been updated
NewHead
end;
true ->
%% The cache was emptied during the delay.
%% Has anything been written since then?
if
Cache#cache.csize =:= 0 ->
%% No, further delayed write not needed.
NewCache = Cache#cache{wrtime = undefined},
Head#head{cache = NewCache};
true ->
%% Yes, schedule a new delayed write.
{MS1,S1,M1} = WrTime,
{MS2,S2,M2} = LastWrTime,
WrT = M1+1000000*(S1+1000000*MS1),
LastWrT = M2+1000000*(S2+1000000*MS2),
When = round((LastWrT - WrT)/1000), Me = self(),
Call = ?DETS_CALL(Me, {delayed_write, LastWrTime}),
erlang:send_after(When, Me, Call),
Head
end
end.
%% -> {NewHead, [LookedUpObject]} | throw({NewHead, Error})
write_cache(Head) ->
{Head1, LU, PwriteList} = (Head#head.mod):write_cache(Head),
{NewHead, ok} = dets_utils:pwrite(Head1, PwriteList),
{NewHead, LU}.
status(Head) ->
case Head#head.update_mode of
saved -> ok;
dirty -> ok;
new_dirty -> ok;
Error -> Error
end.
%%% Scan the file from start to end by reading chunks.
%% -> dets_cont()
init_scan(Head, NoObjs) ->
check_safe_fixtable(Head),
FreeLists = dets_utils:get_freelists(Head),
Base = Head#head.base,
{From, To} = dets_utils:find_next_allocated(FreeLists, Base, Base),
#dets_cont{no_objs = NoObjs, bin = <<>>, alloc = {From, To, <<>>}}.
check_safe_fixtable(Head) ->
case (Head#head.fixed =:= false) andalso
((get(verbose) =:= yes) orelse dets_utils:debug_mode()) of
true ->
error_logger:format
("** dets: traversal of ~p needs safe_fixtable~n",
[Head#head.name]);
false ->
ok
end.
%% -> {[RTerm], dets_cont()} | {scan_error, Reason}
%% RTerm = {Pos, Next, Size, Status, Term}
scan(_Head, #dets_cont{alloc = <<>>}=C) ->
{[], C};
scan(Head, C) -> % when is_record(C, dets_cont)
#dets_cont{no_objs = No, alloc = L0, bin = Bin} = C,
{From, To, L} = L0,
R = case No of
default ->
0;
_ when is_integer(No) ->
-No-1
end,
scan(Bin, Head, From, To, L, [], R, {C, Head#head.type}).
scan(Bin, H, From, To, L, Ts, R, {C0, Type} = C) ->
case (H#head.mod):scan_objs(H, Bin, From, To, L, Ts, R, Type) of
{more, NFrom, NTo, NL, NTs, NR, Sz} ->
scan_read(H, NFrom, NTo, Sz, NL, NTs, NR, C);
{stop, <<>>=B, NFrom, NTo, <<>>=NL, NTs} ->
Ftab = dets_utils:get_freelists(H),
case dets_utils:find_next_allocated(Ftab, NFrom, H#head.base) of
none ->
{NTs, C0#dets_cont{bin = eof, alloc = B}};
_ ->
{NTs, C0#dets_cont{bin = B, alloc = {NFrom, NTo, NL}}}
end;
{stop, B, NFrom, NTo, NL, NTs} ->
{NTs, C0#dets_cont{bin = B, alloc = {NFrom, NTo, NL}}};
bad_object ->
{scan_error, dets_utils:bad_object(scan, {From, To, Bin})}
end.
scan_read(_H, From, To, _Min, L0, Ts,
R, {C, _Type}) when R >= ?CHUNK_SIZE ->
%% We may have read (much) more than CHUNK_SIZE, if there are holes.
L = {From, To, L0},
{Ts, C#dets_cont{bin = <<>>, alloc = L}};
scan_read(H, From, _To, Min, _L, Ts, R, C) ->
Max = if
Min < ?CHUNK_SIZE -> ?CHUNK_SIZE;
true -> Min
end,
FreeLists = dets_utils:get_freelists(H),
case dets_utils:find_allocated(FreeLists, From, Max, H#head.base) of
<<>>=Bin0 ->
{Cont, _} = C,
{Ts, Cont#dets_cont{bin = eof, alloc = Bin0}};
<<From1:32,To1:32,L1/binary>> ->
case dets_utils:pread_n(H#head.fptr, From1, Max) of
eof ->
{scan_error, premature_eof};
NewBin ->
scan(NewBin, H, From1, To1, L1, Ts, R, C)
end
end.
err(Error) ->
case get(verbose) of
yes ->
error_logger:format("** dets: failed with ~w~n", [Error]),
Error;
undefined ->
Error
end.
%%%%%%%%%%%%%%%%% DEBUG functions %%%%%%%%%%%%%%%%
file_info(FileName) ->
case catch read_file_header(FileName, read, false) of
{ok, Fd, FH} ->
file:close(Fd),
(FH#fileheader.mod):file_info(FH);
Other ->
Other
end.
get_head_field(Fd, Field) ->
dets_utils:read_4(Fd, Field).
%% Dump the contents of a DAT file to the tty
%% internal debug function which ignores the closed properly thingie
%% and just tries anyway
view(FileName) ->
case catch read_file_header(FileName, read, false) of
{ok, Fd, FH} ->
Mod = FH#fileheader.mod,
case Mod:check_file_header(FH, Fd) of
{ok, H0, ExtraInfo} ->
Ftab = Mod:init_freelist(H0, ExtraInfo),
{_Bump, Base} = constants(FH, FileName),
H = H0#head{freelists=Ftab, base = Base},
v_free_list(H),
Mod:v_segments(H),
file:close(Fd);
X ->
file:close(Fd),
X
end;
X ->
X
end.
v_free_list(Head) ->
io:format("FREE LIST ...... \n",[]),
io:format("~p~n", [dets_utils:all_free(Head)]),
io:format("END OF FREE LIST \n",[]).
