%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2001-2011. 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_v8).
%% Dets files, implementation part. This module handles versions up to
%% and including 8(c). To be called from dets.erl only.
-export([mark_dirty/1, read_file_header/2,
check_file_header/2, do_perform_save/1, initiate_file/11,
init_freelist/2, fsck_input/4,
bulk_input/3, output_objs/4, write_cache/1, may_grow/3,
find_object/2, re_hash/2, slot_objs/2, scan_objs/8,
db_hash/2, no_slots/1, table_parameters/1]).
-export([file_info/1, v_segments/1]).
-export([cache_segps/3]).
%% For backward compatibility.
-export([sz2pos/1]).
-compile({inline, [{sz2pos,1},{scan_skip,7}]}).
-compile({inline, [{skip_bytes,5}, {get_segp,1}]}).
-compile({inline, [{wl_lookup,5}]}).
-compile({inline, [{actual_seg_size,0}]}).
-include("dets.hrl").
%% The layout of the file is :
%%
%% bytes decsription
%% ---------------------- File header
%% 4 FreelistsPointer
%% 4 Cookie
%% 4 ClosedProperly (pos=8)
%% 4 Type (pos=12)
%% 4 Version (pos=16)
%% 4 M
%% 4 Next
%% 4 KeyPos
%% 4 NoObjects
%% 4 N
%% ------------------ end of file header
%% 4*8192 SegmentArray
%% ------------------
%% 4*256 First segment
%% ----------------------------- This is BASE.
%% ??? Objects (free and alive)
%% 4*256 Second segment (2 kB now, due to a bug)
%% ??? Objects (free and alive)
%% ... more objects and segments ...
%% -----------------------------
%% ??? Free lists
%% -----------------------------
%% 4 File size, in bytes.
%% The first slot (0) in the segment array always points to the
%% pre-allocated first segment.
%% Before we can find an object we must find the slot where the
%% object resides. Each slot is a (possibly empty) list (or chain) of
%% objects that hash to the same slot. If the value stored in the
%% slot is zero, the slot chain is empty. If the slot value is
%% non-zero, the value points to a position in the file where the
%% chain starts. Each object in a chain has the following layout:
%%
%% bytes decsription
%% --------------------
%% 4 Pointer to the next object of the chain.
%% 4 Size of the object in bytes (Sz).
%% 4 Status (FREE or ACTIVE)
%% Sz Binary representing the object
%%
%% The status field is used while repairing a file (but not next or size).
%%
%%|---------------|
%%| head |
%%| |
%%| |
%%|_______________|
%%| |------|
%%|___seg ptr1____| |
%%| | |
%%|__ seg ptr 2___| |
%%| | | segment 1
%%| .... | V _____________
%% | |
%% | |
%% |___slot 0 ____|
%% | |
%% |___slot 1 ____|-----|
%% | | |
%% | ..... | | 1:st obj in slot 1
%% V segment 1
%% |-----------|
%% | next |
%% |___________|
%% | size |
%% |___________|
%% | status |
%% |___________|
%% | |
%% | |
%% | obj |
%% | |
%%%
%%% File header
%%%
-define(HEADSZ, 40). % The size of the file header, in bytes.
-define(SEGSZ, 256). % Size of a segment, in words.
-define(SEGSZ_LOG2, 8).
-define(SEGARRSZ, 8192). % Maximal number of segments.
-define(SEGADDR(SegN), (?HEADSZ + (4 * (SegN)))).
-define(BASE, ?SEGADDR((?SEGSZ + ?SEGARRSZ))).
-define(MAXOBJS, (?SEGSZ * ?SEGARRSZ)). % 2 M objects
-define(SLOT2SEG(S), ((S) bsr ?SEGSZ_LOG2)).
%% BIG is used for hashing. BIG must be greater than the maximum
%% number of slots, currently MAXOBJS.
-define(BIG, 16#ffffff).
%% Hard coded positions into the file header:
-define(FREELIST_POS, 0).
-define(CLOSED_PROPERLY_POS, 8).
-define(D_POS, 20).
-define(NO_OBJECTS_POS, (?D_POS + 12)).
%% The version of a dets file is indicated by the ClosedProperly
%% field. Version 6 was used in the R1A release, and version 7 in the
%% R1B release up to and including the R3B01 release. Both version 6
%% and version 7 indicate properly closed files by the value
%% CLOSED_PROPERLY.
%%
%% The current version, 8, has three sub-versions:
%%
%% - 8(a), indicated by the value CLOSED_PROPERLY (same as in versions 6
%% and 7), introduced in R3B02;
%% - 8(b), indicated by the value CLOSED_PROPERLY2(_NEED_COMPACTING),
%% introduced in R5A and used up to and including R6A;
%% - 8(c), indicated by the value CLOSED_PROPERLY_NEW_HASH(_NEED_COMPACTING),
%% in use since R6B.
%%
%% The difference between the 8(a) and the 8(b) versions is the format
%% used for free lists saved on dets files.
%% The 8(c) version uses a different hashing algorithm, erlang:phash
%% (former versions use erlang:hash).
%% Version 8(b) files are only converted to version 8(c) if repair is
%% done, so we need compatibility with 8(b) for a _long_ time.
%%
%% There are known bugs due to the fact that keys and objects are
%% sometimes compared (==) and sometimes matched (=:=). The version
%% used by default (9, see dets_v9.erl) does not have this problem.
-define(NOT_PROPERLY_CLOSED,0).
-define(CLOSED_PROPERLY,1).
-define(CLOSED_PROPERLY2,2).
-define(CLOSED_PROPERLY2_NEED_COMPACTING,3).
-define(CLOSED_PROPERLY_NEW_HASH,4).
-define(CLOSED_PROPERLY_NEW_HASH_NEED_COMPACTING,5).
-define(FILE_FORMAT_VERSION, 8).
-define(CAN_BUMP_BY_REPAIR, [6, 7]).
-define(CAN_CONVERT_FREELIST, [8]).
%%%
%%% Object header (next, size, status).
%%%
-define(OHDSZ, 12). % The size of the object header, in bytes.
-define(STATUS_POS, 8). % Position of the status field.
%% The size of each object is a multiple of 16.
%% BUMP is used when repairing files.
-define(BUMP, 16).
-define(ReadAhead, 512).
%%-define(DEBUGF(X,Y), io:format(X, Y)).
-define(DEBUGF(X,Y), void).
%% -> ok | throw({NewHead,Error})
mark_dirty(Head) ->
Dirty = [{?CLOSED_PROPERLY_POS, <<?NOT_PROPERLY_CLOSED:32>>}],
dets_utils:pwrite(Head, Dirty),
dets_utils:sync(Head),
dets_utils:position(Head, Head#head.freelists_p),
dets_utils:truncate(Head, cur).
%% -> {ok, head()} | throw(Error)
initiate_file(Fd, Tab, Fname, Type, Kp, MinSlots, MaxSlots,
Ram, CacheSz, Auto, _DoInitSegments) ->
Freelist = 0,
Cookie = ?MAGIC,
ClosedProperly = ?NOT_PROPERLY_CLOSED, % immediately overwritten
Version = ?FILE_FORMAT_VERSION,
Factor = est_no_segments(MinSlots),
N = 0,
M = Next = ?SEGSZ * Factor,
NoObjects = 0,
dets_utils:pwrite(Fd, Fname, 0,
<<Freelist:32,
Cookie:32,
ClosedProperly:32,
(dets_utils:type_to_code(Type)):32,
Version:32,
M:32,
Next:32,
Kp:32,
NoObjects:32,
N:32,
0:(?SEGARRSZ*4)/unit:8, % Initialize SegmentArray
0:(?SEGSZ*4)/unit:8>>), % Initialize first segment
%% We must set the first slot of the segment pointer array to
%% point to the first segment
Pos = ?SEGADDR(0),
SegP = (?HEADSZ + (4 * ?SEGARRSZ)),
dets_utils:pwrite(Fd, Fname, Pos, <<SegP:32>>),
segp_cache(Pos, SegP),
Ftab = dets_utils:init_alloc(?BASE),
H0 = #head{freelists=Ftab, fptr = Fd, base = ?BASE},
{H1, Ws} = init_more_segments(H0, 1, Factor, undefined, []),
%% This is not optimal but simple: always initiate the segments.
dets_utils:pwrite(Fd, Fname, Ws),
%% Return a new nice head structure
Head = #head{
m = M,
m2 = M * 2,
next = Next,
fptr = Fd,
no_objects = NoObjects,
n = N,
type = Type,
update_mode = dirty,
freelists = H1#head.freelists,
auto_save = Auto,
hash_bif = phash,
keypos = Kp,
min_no_slots = Factor * ?SEGSZ,
max_no_slots = no_segs(MaxSlots) * ?SEGSZ,
ram_file = Ram,
filename = Fname,
name = Tab,
cache = dets_utils:new_cache(CacheSz),
version = Version,
bump = ?BUMP,
base = ?BASE,
mod = ?MODULE
},
{ok, Head}.
est_no_segments(MinSlots) when 1 + ?SLOT2SEG(MinSlots) > ?SEGARRSZ ->
?SEGARRSZ;
est_no_segments(MinSlots) ->
1 + ?SLOT2SEG(MinSlots).
init_more_segments(Head, SegNo, Factor, undefined, Ws) when SegNo < Factor ->
init_more_segments(Head, SegNo, Factor, seg_zero(), Ws);
init_more_segments(Head, SegNo, Factor, SegZero, Ws) when SegNo < Factor ->
{NewHead, W} = allocate_segment(Head, SegZero, SegNo),
init_more_segments(NewHead, SegNo+1, Factor, SegZero, W++Ws);
init_more_segments(Head, _SegNo, _Factor, _SegZero, Ws) ->
{Head, Ws}.
allocate_segment(Head, SegZero, SegNo) ->
%% may throw error:
{NewHead, Segment, _} = dets_utils:alloc(Head, 4 * ?SEGSZ),
InitSegment = {Segment, SegZero},
Pos = ?SEGADDR(SegNo),
segp_cache(Pos, Segment),
SegPointer = {Pos, <<Segment:32>>},
{NewHead, [InitSegment, SegPointer]}.
%% Read free lists (using a Buddy System) from file.
init_freelist(Head, {convert_freelist,_Version}) ->
%% This function converts the saved freelist of the form
%% [{Slot1,Addr1},{Addr1,Addr2},...,{AddrN,0},{Slot2,Addr},...]
%% i.e each slot is a linked list which ends with a 0.
%% This is stored in a bplus_tree per Slot.
%% Each Slot is a position in a tuple.
Ftab = dets_utils:empty_free_lists(),
Pos = Head#head.freelists_p,
case catch prterm(Head, Pos, ?OHDSZ) of
{0, _Sz, Term} ->
FreeList1 = lists:reverse(Term),
FreeList = dets_utils:init_slots_from_old_file(FreeList1, Ftab),
Head#head{freelists = FreeList, base = ?BASE};
_ ->
throw({error, {bad_freelists, Head#head.filename}})
end;
init_freelist(Head, _) ->
%% bplus_tree stored as is
Pos = Head#head.freelists_p,
case catch prterm(Head, Pos, ?OHDSZ) of
{0, _Sz, Term} ->
Head#head{freelists = Term, base = ?BASE};
_ ->
throw({error, {bad_freelists, Head#head.filename}})
end.
%% -> {ok, Fd, fileheader()} | throw(Error)
read_file_header(Fd, FileName) ->
{ok, Bin} = dets_utils:pread_close(Fd, FileName, 0, ?HEADSZ),
[Freelist, Cookie, CP, Type2, Version, M, Next, Kp, NoObjects, N] =
bin2ints(Bin),
{ok, EOF} = dets_utils:position_close(Fd, FileName, eof),
{ok, <<FileSize:32>>} = dets_utils:pread_close(Fd, FileName, EOF-4, 4),
FH = #fileheader{freelist = Freelist,
fl_base = ?BASE,
cookie = Cookie,
closed_properly = CP,
type = dets_utils:code_to_type(Type2),
version = Version,
m = M,
next = Next,
keypos = Kp,
no_objects = NoObjects,
min_no_slots = ?DEFAULT_MIN_NO_SLOTS,
max_no_slots = ?DEFAULT_MAX_NO_SLOTS,
trailer = FileSize,
eof = EOF,
n = N,
mod = ?MODULE},
{ok, Fd, FH}.
%% -> {ok, head(), ExtraInfo} | {error, Reason} (Reason lacking file name)
%% ExtraInfo = {convert_freelist, Version} | true | need_compacting
check_file_header(FH, Fd) ->
Test =
if
FH#fileheader.cookie =/= ?MAGIC ->
{error, not_a_dets_file};
FH#fileheader.type =:= badtype ->
{error, invalid_type_code};
FH#fileheader.version =/= ?FILE_FORMAT_VERSION ->
case lists:member(FH#fileheader.version,
?CAN_BUMP_BY_REPAIR) of
true ->
{error, version_bump};
false ->
{error, bad_version}
end;
FH#fileheader.trailer =/= FH#fileheader.eof ->
{error, not_closed};
FH#fileheader.closed_properly =:= ?CLOSED_PROPERLY ->
case lists:member(FH#fileheader.version,
?CAN_CONVERT_FREELIST) of
true ->
{ok, {convert_freelist, FH#fileheader.version}, hash};
false ->
{error, not_closed} % should not happen
end;
FH#fileheader.closed_properly =:= ?CLOSED_PROPERLY2 ->
{ok, true, hash};
FH#fileheader.closed_properly =:=
?CLOSED_PROPERLY2_NEED_COMPACTING ->
{ok, need_compacting, hash};
FH#fileheader.closed_properly =:= ?CLOSED_PROPERLY_NEW_HASH ->
{ok, true, phash};
FH#fileheader.closed_properly =:=
?CLOSED_PROPERLY_NEW_HASH_NEED_COMPACTING ->
{ok, need_compacting, phash};
FH#fileheader.closed_properly =:= ?NOT_PROPERLY_CLOSED ->
{error, not_closed};
FH#fileheader.closed_properly >
?CLOSED_PROPERLY_NEW_HASH_NEED_COMPACTING ->
{error, not_closed};
true ->
{error, not_a_dets_file}
end,
case Test of
{ok, ExtraInfo, HashAlg} ->
H = #head{
m = FH#fileheader.m,
m2 = FH#fileheader.m * 2,
next = FH#fileheader.next,
fptr = Fd,
no_objects= FH#fileheader.no_objects,
n = FH#fileheader.n,
type = FH#fileheader.type,
update_mode = saved,
auto_save = infinity, % not saved on file
fixed = false, % not saved on file
freelists_p = FH#fileheader.freelist,
hash_bif = HashAlg,
keypos = FH#fileheader.keypos,
min_no_slots = FH#fileheader.min_no_slots,
max_no_slots = FH#fileheader.max_no_slots,
version = ?FILE_FORMAT_VERSION,
mod = ?MODULE,
bump = ?BUMP,
base = FH#fileheader.fl_base},
{ok, H, ExtraInfo};
Error ->
Error
end.
cache_segps(Fd, FileName, M) ->
NSegs = no_segs(M),
{ok, Bin} = dets_utils:pread_close(Fd, FileName, ?HEADSZ, 4 * NSegs),
Fun = fun(S, P) -> segp_cache(P, S), P+4 end,
lists:foldl(Fun, ?HEADSZ, bin2ints(Bin)).
no_segs(NoSlots) ->
?SLOT2SEG(NoSlots - 1) + 1.
bin2ints(<<Int:32, B/binary>>) ->
[Int | bin2ints(B)];
bin2ints(<<>>) ->
[].
%%%
%%% Repair, conversion and initialization of a dets file.
%%%
bulk_input(Head, InitFun, Cntrs) ->
bulk_input(Head, InitFun, Cntrs, make_ref()).
bulk_input(Head, InitFun, Cntrs, Ref) ->
fun(close) ->
ok;
(read) ->
case catch {Ref, InitFun(read)} of
{Ref, end_of_input} ->
end_of_input;
{Ref, {L0, NewInitFun}} when is_list(L0),
is_function(NewInitFun) ->
Kp = Head#head.keypos,
case catch bulk_objects(L0, Head, Cntrs, Kp, []) of
{'EXIT', _Error} ->
_ = (catch NewInitFun(close)),
{error, invalid_objects_list};
L ->
{L, bulk_input(Head, NewInitFun, Cntrs, Ref)}
end;
{Ref, Value} ->
{error, {init_fun, Value}};
Error ->
throw({thrown, Error})
end
end.
bulk_objects([T | Ts], Head, Cntrs, Kp, L) ->
BT = term_to_binary(T),
Sz = byte_size(BT),
LogSz = sz2pos(Sz+?OHDSZ),
count_object(Cntrs, LogSz),
Key = element(Kp, T),
bulk_objects(Ts, Head, Cntrs, Kp, [make_object(Head, Key, LogSz, BT) | L]);
bulk_objects([], _Head, _Cntrs, _Kp, L) ->
L.
-define(FSCK_SEGMENT, 10000).
-define(DCT(D, CT), [D | CT]).
-define(VNEW(N, E), erlang:make_tuple(N, E)).
-define(VSET(I, V, E), setelement(I, V, E)).
-define(VGET(I, V), element(I, V)).
%% OldVersion not used, assuming later versions have been converted already.
output_objs(OldVersion, Head, SlotNumbers, Cntrs) ->
fun(close) ->
{ok, 0, Head};
([]) ->
output_objs(OldVersion, Head, SlotNumbers, Cntrs);
(L) ->
%% Descending sizes.
Count = lists:sort(ets:tab2list(Cntrs)),
RCount = lists:reverse(Count),
NoObjects = lists:foldl(fun({_Sz,No}, A) -> A + No end, 0, Count),
{_, MinSlots, _} = SlotNumbers,
if
%% Using number of objects for bags and duplicate bags
%% is not ideal; number of (unique) keys should be
%% used instead. The effect is that there will be more
%% segments than "necessary".
MinSlots =/= bulk_init,
abs(?SLOT2SEG(NoObjects) - ?SLOT2SEG(MinSlots)) > 5,
(NoObjects < ?MAXOBJS) ->
{try_again, NoObjects};
true ->
Head1 = Head#head{no_objects = NoObjects},
SegSz = actual_seg_size(),
{_, End, _} = dets_utils:alloc(Head, SegSz-1),
%% Now {LogSize,NoObjects} in Cntrs is replaced by
%% {LogSize,Position,{FileName,FileDescriptor},NoObjects}.
{Head2, CT} = allocate_all_objects(Head1, RCount, Cntrs),
[E | Es] = bin2term(L, []),
{NE, Acc, DCT1} =
output_slots(E, Es, [E], Head2, ?DCT(0, CT)),
NDCT = write_all_sizes(DCT1, Cntrs),
Max = ets:info(Cntrs, size),
output_objs2(NE, Acc, Head2, Cntrs, NDCT, End, Max,Max)
end
end.
output_objs2(E, Acc, Head, Cntrs, DCT, End, 0, MaxNoChunks) ->
NDCT = write_all_sizes(DCT, Cntrs),
output_objs2(E, Acc, Head, Cntrs, NDCT, End, MaxNoChunks, MaxNoChunks);
output_objs2(E, Acc, Head, Cntrs, DCT, End, ChunkI, MaxNoChunks) ->
fun(close) ->
DCT1 = output_slot(Acc, Head, DCT),
NDCT = write_all_sizes(DCT1, Cntrs),
?DCT(NoDups, CT) = NDCT,
[SegAddr | []] = ?VGET(tuple_size(CT), CT),
FinalZ = End - SegAddr,
[{?FSCK_SEGMENT, _, {FileName, Fd}, _}] =
ets:lookup(Cntrs, ?FSCK_SEGMENT),
ok = dets_utils:fwrite(Fd, FileName,
dets_utils:make_zeros(FinalZ)),
NewHead = Head#head{no_objects = Head#head.no_objects - NoDups},
{ok, NoDups, NewHead};
(L) ->
Es = bin2term(L, []),
{NE, NAcc, NDCT} = output_slots(E, Es, Acc, Head, DCT),
output_objs2(NE, NAcc, Head, Cntrs, NDCT, End,
ChunkI-1, MaxNoChunks)
end.
%% By allocating bigger objects before smaller ones, holes in the
%% buddy system memory map are avoided. Unfortunately, the segments
%% are always allocated first, so if there are objects bigger than a
%% segment, there is a hole to handle. (Haven't considered placing the
%% segments among other objects of the same size.)
allocate_all_objects(Head, Count, Cntrs) ->
SegSize = actual_seg_size(),
{Head1, HSz, HN, HA} = alloc_hole(Count, Head, SegSize),
{Max, _} = hd(Count),
CT = ?VNEW(Max+1, not_used),
{Head2, NCT} = allocate_all(Head1, Count, Cntrs, CT),
Head3 = free_hole(Head2, HSz, HN, HA),
{Head3, NCT}.
alloc_hole([{LSize,_} | _], Head, SegSz) when ?POW(LSize-1) > SegSz ->
{_, SegAddr, _} = dets_utils:alloc(Head, SegSz-1),
Size = ?POW(LSize-1)-1,
{_, Addr, _} = dets_utils:alloc(Head, Size),
N = (Addr - SegAddr) div SegSz,
Head1 = dets_utils:alloc_many(Head, SegSz, N, SegAddr),
{Head1, SegSz-1, N, SegAddr};
alloc_hole(_Count, Head, _SegSz) ->
{Head, 0, 0, 0}.
free_hole(Head, _Size, 0, _Addr) ->
Head;
free_hole(Head, Size, N, Addr) ->
{Head1, _} = dets_utils:free(Head, Addr, Size),
free_hole(Head1, Size, N-1, Addr+Size+1).
%% One (temporary) file for each buddy size, write all objects of that
%% size to the file.
allocate_all(Head, [{LSize,NoObjects} | Count], Cntrs, CT) ->
Size = ?POW(LSize-1)-1,
{_Head, Addr, _} = dets_utils:alloc(Head, Size),
NewHead = dets_utils:alloc_many(Head, Size+1, NoObjects, Addr),
{FileName, Fd} = temp_file(Head, LSize),
true = ets:insert(Cntrs, {LSize, Addr, {FileName, Fd}, NoObjects}),
NCT = ?VSET(LSize, CT, [Addr | []]),
allocate_all(NewHead, Count, Cntrs, NCT);
allocate_all(Head, [], Cntrs, CT) ->
%% Note that space for the segments has been allocated already.
%% And one file for the segments...
{FileName, Fd} = temp_file(Head, ?FSCK_SEGMENT),
Addr = ?SEGADDR(?SEGARRSZ),
true = ets:insert(Cntrs, {?FSCK_SEGMENT, Addr, {FileName, Fd}, 0}),
NCT = ?VSET(tuple_size(CT), CT, [Addr | []]),
{Head, NCT}.
temp_file(Head, N) ->
TmpName = lists:concat([Head#head.filename, '.', N]),
{ok, Fd} = dets_utils:open(TmpName, [raw, binary, write]),
{TmpName, Fd}.
bin2term([<<Slot:32, LogSize:8, BinTerm/binary>> | BTs], L) ->
bin2term(BTs, [{Slot, LogSize, BinTerm} | L]);
bin2term([], L) ->
lists:reverse(L).
write_all_sizes(?DCT(D, CT), Cntrs) ->
?DCT(D, write_sizes(1, tuple_size(CT), CT, Cntrs)).
write_sizes(Sz, Sz, CT, Cntrs) ->
write_size(Sz, ?FSCK_SEGMENT, CT, Cntrs);
write_sizes(Sz, MaxSz, CT, Cntrs) ->
NCT = write_size(Sz, Sz, CT, Cntrs),
write_sizes(Sz+1, MaxSz, NCT, Cntrs).
write_size(Sz, I, CT, Cntrs) ->
case ?VGET(Sz, CT) of
not_used ->
CT;
[Addr | L] ->
{FileName, Fd} = ets:lookup_element(Cntrs, I, 3),
case file:write(Fd, lists:reverse(L)) of
ok ->
?VSET(Sz, CT, [Addr | []]);
Error ->
dets_utils:file_error(FileName, Error)
end
end.
output_slots(E, [E1 | Es], Acc, Head, DCT)
when element(1, E) =:= element(1, E1) ->
output_slots(E1, Es, [E1 | Acc], Head, DCT);
output_slots(_E, [E | L], Acc, Head, DCT) ->
NDCT = output_slot(Acc, Head, DCT),
output_slots(E, L, [E], Head, NDCT);
output_slots(E, [], Acc, _Head, DCT) ->
{E, Acc, DCT}.
output_slot([E], _Head, ?DCT(D, CT)) ->
?DCT(D, output_slot([{foo, E}], 0, foo, CT));
output_slot(Es0, Head, ?DCT(D, CT)) ->
Kp = Head#head.keypos,
Fun = fun({_Slot, _LSize, BinTerm} = E) ->
Key = element(Kp, binary_to_term(BinTerm)),
{Key, E}
end,
Es = lists:map(Fun, Es0),
NEs = case Head#head.type of
set ->
[{Key0,_} = E | L0] = lists:sort(Es),
choose_one(lists:sort(L0), Key0, [E]);
bag ->
lists:usort(Es);
duplicate_bag ->
lists:sort(Es)
end,
Dups = D + length(Es) - length(NEs),
?DCT(Dups, output_slot(NEs, 0, foo, CT)).
choose_one([{Key,_} | Es], Key, L) ->
choose_one(Es, Key, L);
choose_one([{Key,_} = E | Es], _Key, L) ->
choose_one(Es, Key, [E | L]);
choose_one([], _Key, L) ->
L.
output_slot([E | Es], Next, _Slot, CT) ->
{_Key, {Slot, LSize, BinTerm}} = E,
Size = byte_size(BinTerm),
Size2 = ?POW(LSize-1),
Pad = <<0:(Size2-Size-?OHDSZ)/unit:8>>,
BinObject = [<<Next:32, Size:32, ?ACTIVE:32>>, BinTerm | Pad],
[Addr | L] = ?VGET(LSize, CT),
NCT = ?VSET(LSize, CT, [Addr+Size2 | [BinObject | L]]),
output_slot(Es, Addr, Slot, NCT);
output_slot([], Next, Slot, CT) ->
I = tuple_size(CT),
[Addr | L] = ?VGET(I, CT),
{Pos, _} = slot_position(Slot),
NoZeros = Pos - Addr,
BinObject = if
NoZeros > 100 ->
[dets_utils:make_zeros(NoZeros) | <<Next:32>>];
true ->
<<0:NoZeros/unit:8,Next:32>>
end,
Size = NoZeros+4,
?VSET(I, CT, [Addr+Size | [BinObject | L]]).
%% Does not close Fd.
fsck_input(Head, Fd, Cntrs, _FileHeader) ->
%% The file is not compressed, so the object size cannot exceed
%% the filesize, for all objects.
MaxSz = case file:position(Fd, eof) of
{ok, Pos} ->
Pos;
_ ->
(1 bsl 32) - 1
end,
State0 = fsck_read(?BASE, Fd, []),
fsck_input1(Head, State0, Fd, MaxSz, Cntrs).
fsck_input1(Head, State, Fd, MaxSz, Cntrs) ->
fun(close) ->
ok;
(read) ->
case State of
done ->
end_of_input;
{done, L} ->
R = count_input(Cntrs, L, []),
{R, fsck_input1(Head, done, Fd, MaxSz, Cntrs)};
{cont, L, Bin, Pos} ->
R = count_input(Cntrs, L, []),
FR = fsck_objs(Bin, Head#head.keypos, Head, []),
NewState = fsck_read(FR, Pos, Fd, MaxSz, Head),
{R, fsck_input1(Head, NewState, Fd, MaxSz, Cntrs)}
end
end.
%% The ets table Cntrs is used for counting objects per size.
count_input(Cntrs, [[LogSz | B] | Ts], L) ->
count_object(Cntrs, LogSz),
count_input(Cntrs, Ts, [B | L]);
count_input(_Cntrs, [], L) ->
L.
count_object(Cntrs, LogSz) ->
case catch ets:update_counter(Cntrs, LogSz, 1) of
N when is_integer(N) -> ok;
_Badarg -> true = ets:insert(Cntrs, {LogSz, 1})
end.
fsck_read(Pos, F, L) ->
case file:position(F, Pos) of
{ok, _} ->
read_more_bytes(<<>>, 0, Pos, F, L);
_Error ->
{done, L}
end.
fsck_read({more, Bin, Sz, L}, Pos, F, MaxSz, Head) when Sz > MaxSz ->
FR = skip_bytes(Bin, ?BUMP, Head#head.keypos, Head, L),
fsck_read(FR, Pos, F, MaxSz, Head);
fsck_read({more, Bin, Sz, L}, Pos, F, _MaxSz, _Head) ->
read_more_bytes(Bin, Sz, Pos, F, L);
fsck_read({new, Skip, L}, Pos, F, _MaxSz, _Head) ->
NewPos = Pos + Skip,
fsck_read(NewPos, F, L).
read_more_bytes(B, Min, Pos, F, L) ->
Max = if
Min < ?CHUNK_SIZE -> ?CHUNK_SIZE;
true -> Min
end,
case dets_utils:read_n(F, Max) of
eof ->
{done, L};
Bin ->
NewPos = Pos + byte_size(Bin),
{cont, L, list_to_binary([B, Bin]), NewPos}
end.
fsck_objs(Bin = <<_N:32, Sz:32, Status:32, Tail/binary>>, Kp, Head, L) ->
if
Status =:= ?ACTIVE ->
case Tail of
<<BinTerm:Sz/binary, Tail2/binary>> ->
case catch element(Kp, binary_to_term(BinTerm)) of
{'EXIT', _} ->
skip_bytes(Bin, ?BUMP, Kp, Head, L);
Key ->
LogSz = sz2pos(Sz+?OHDSZ),
Obj = make_object(Head, Key, LogSz, BinTerm),
NL = [[LogSz | Obj] | L],
Skip = ?POW(LogSz-1) - Sz - ?OHDSZ,
skip_bytes(Tail2, Skip, Kp, Head, NL)
end;
_ ->
{more, Bin, Sz, L}
end;
true ->
skip_bytes(Bin, ?BUMP, Kp, Head, L)
end;
fsck_objs(Bin, _Kp, _Head, L) ->
{more, Bin, 0, L}.
%% Version 8 has to know about version 9.
make_object(Head, Key, _LogSz, BT) when Head#head.version =:= 9 ->
Slot = dets_v9:db_hash(Key, Head),
<<Slot:32, BT/binary>>;
make_object(Head, Key, LogSz, BT) ->
Slot = db_hash(Key, Head),
<<Slot:32, LogSz:8, BT/binary>>.
%% Inlined.
skip_bytes(Bin, Skip, Kp, Head, L) ->
case Bin of
<<_:Skip/binary, Tail/binary>> ->
fsck_objs(Tail, Kp, Head, L);
_ ->
{new, Skip - byte_size(Bin), L}
end.
%% -> {NewHead, ok} | throw({Head, Error})
do_perform_save(H) ->
FL = dets_utils:get_freelists(H),
B = term_to_binary(FL),
Size = byte_size(B),
?DEBUGF("size of freelist = ~p~n", [Size]),
?DEBUGF("head.m = ~p~n", [H#head.m]),
?DEBUGF("head.no_objects = ~p~n", [H#head.no_objects]),
{ok, Pos} = dets_utils:position(H, eof),
H1 = H#head{freelists_p = Pos},
W1 = {?FREELIST_POS, <<Pos:32>>},
W2 = {Pos, [<<0:32, Size:32, ?FREE:32>>, B]},
W3 = {?D_POS, <<(H1#head.m):32,
(H1#head.next):32,
(H1#head.keypos):32,
(H1#head.no_objects):32,
(H1#head.n):32>>},
{ClosedProperly, ClosedProperlyNeedCompacitng} =
case H1#head.hash_bif of
hash ->
{?CLOSED_PROPERLY2, ?CLOSED_PROPERLY2_NEED_COMPACTING};
phash ->
{?CLOSED_PROPERLY_NEW_HASH,
?CLOSED_PROPERLY_NEW_HASH_NEED_COMPACTING}
end,
W4 =
if
Size > 1000, Size > H1#head.no_objects ->
{?CLOSED_PROPERLY_POS,
<<ClosedProperlyNeedCompacitng:32>>};
true ->
{?CLOSED_PROPERLY_POS, <<ClosedProperly:32>>}
end,
W5 = {?FILE_FORMAT_VERSION_POS, <<?FILE_FORMAT_VERSION:32>>},
{H2, ok} = dets_utils:pwrite(H1, [W1,W2,W3,W4,W5]),
{ok, Pos2} = dets_utils:position(H2, eof),
?DEBUGF("Writing file size ~p, eof at ~p~n", [Pos2+4, Pos2]),
dets_utils:pwrite(H2, [{Pos2, <<(Pos2 + 4):32>>}]).
%% -> [term()] | throw({Head, Error})
slot_objs(H, Slot) when Slot >= H#head.next ->
'$end_of_table';
slot_objs(H, Slot) ->
{_Pos, Chain} = chain(H, Slot),
collect_chain(H, Chain).
collect_chain(_H, 0) -> [];
collect_chain(H, Pos) ->
{Next, _Sz, Term} = prterm(H, Pos, ?ReadAhead),
[Term | collect_chain(H, Next)].
db_hash(Key, Head) ->
H = h(Key, Head#head.hash_bif),
Hash = H rem Head#head.m,
if
Hash < Head#head.n ->
H rem (Head#head.m2); % H rem (2 * m)
true ->
Hash
end.
h(I, phash) -> erlang:phash(I, ?BIG) - 1;
h(I, HF) -> erlang:HF(I, ?BIG) - 1. %% stupid BIF has 1 counts.
no_slots(_Head) ->
undefined.
table_parameters(_Head) ->
undefined.
%% Re-hashing a segment, starting with SlotStart.
%%
%% On the average, half of the objects of the chain are put into a new
%% chain. If the slot of the old chain is i, then the slot of the new
%% chain is i+m.
%% Note that the insertion of objects into the new chain is simplified
%% by the fact that the chains are not sorted on key, which means that
%% each moved object can be inserted first in the new chain.
%% (It is also a fact that the objects with the same key are not sorted.)
%%
%% -> {ok, Writes} | throw({Head, Error})
re_hash(Head, SlotStart) ->
{SlotPos, _4} = slot_position(SlotStart),
{ok, Bin} = dets_utils:pread(Head, SlotPos, 4*?SEGSZ, 0),
{Read, Cs} = split_bin(SlotPos, Bin, [], []),
re_hash_read(Head, [], Read, Cs).
split_bin(Pos, <<P:32, B/binary>>, R, Cs) ->
if
P =:= 0 ->
split_bin(Pos+4, B, R, Cs);
true ->
split_bin(Pos+4, B, [{P,?ReadAhead} | R], [[Pos] | Cs])
end;
split_bin(_Pos, <<>>, R, Cs) ->
{R, Cs}.
re_hash_read(Head, Cs, R, RCs) ->
{ok, Bins} = dets_utils:pread(R, Head),
re_hash_read(Head, R, RCs, Bins, Cs, [], []).
re_hash_read(Head, [{Pos, Size} | Ps], [C | Cs],
[<<Next:32, Sz:32, _Status:32, Bin0/binary>> | Bins],
DoneCs, R, RCs) ->
case byte_size(Bin0) of
BinSz when BinSz >= Sz ->
case catch binary_to_term(Bin0) of
{'EXIT', _Error} ->
throw(dets_utils:corrupt_reason(Head, bad_object));
Term ->
Key = element(Head#head.keypos, Term),
New = h(Key, Head#head.hash_bif) rem Head#head.m2,
NC = case New >= Head#head.m of
true -> [{Pos,New} | C];
false -> [Pos | C]
end,
if
Next =:= 0 ->
NDoneCs = [NC | DoneCs],
re_hash_read(Head, Ps, Cs, Bins, NDoneCs, R, RCs);
true ->
NR = [{Next,?ReadAhead} | R],
NRCs = [NC | RCs],
re_hash_read(Head, Ps, Cs, Bins, DoneCs, NR, NRCs)
end
end;
BinSz when Size =:= BinSz+?OHDSZ ->
NR = [{Pos, Sz+?OHDSZ} | R],
re_hash_read(Head, Ps, Cs, Bins, DoneCs, NR, [C | RCs]);
_BinSz ->
throw({Head, {error, {premature_eof, Head#head.filename}}})
end;
re_hash_read(Head, [], [], [], Cs, [], []) ->
re_hash_traverse_chains(Cs, Head, [], [], []);
re_hash_read(Head, [], [], [], Cs, R, RCs) ->
re_hash_read(Head, Cs, R, RCs).
re_hash_traverse_chains([C | Cs], Head, Rs, Ns, Ws) ->
case re_hash_find_new(C, Rs, start, start) of
false ->
re_hash_traverse_chains(Cs, Head, Rs, Ns, Ws);
{NRs, FirstNew, LastNew} ->
LastInNew = case C of
[{_,_} | _] -> true;
_ -> false
end,
N = {FirstNew, LastNew, LastInNew},
NWs = re_hash_link(C, start, start, start, Ws),
re_hash_traverse_chains(Cs, Head, NRs, [N | Ns], NWs)
end;
re_hash_traverse_chains([], Head, Rs, Ns, Ws) ->
{ok, Bins} = dets_utils:pread(Rs, Head),
{ok, insert_new(Rs, Bins, Ns, Ws)}.
re_hash_find_new([{Pos,NewSlot} | C], R, start, start) ->
{SPos, _4} = slot_position(NewSlot),
re_hash_find_new(C, [{SPos,4} | R], Pos, Pos);
re_hash_find_new([{Pos,_SPos} | C], R, _FirstNew, LastNew) ->
re_hash_find_new(C, R, Pos, LastNew);
re_hash_find_new([_Pos | C], R, FirstNew, LastNew) ->
re_hash_find_new(C, R, FirstNew, LastNew);
re_hash_find_new([], _R, start, start) ->
false;
re_hash_find_new([], R, FirstNew, LastNew) ->
{R, FirstNew, LastNew}.
re_hash_link([{Pos,_SPos} | C], LastOld, start, _LastInNew, Ws) ->
re_hash_link(C, LastOld, Pos, true, Ws);
re_hash_link([{Pos,_SPos} | C], LastOld, LastNew, false, Ws) ->
re_hash_link(C, LastOld, Pos, true, [{Pos,<<LastNew:32>>} | Ws]);
re_hash_link([{Pos,_SPos} | C], LastOld, _LastNew, LastInNew, Ws) ->
re_hash_link(C, LastOld, Pos, LastInNew, Ws);
re_hash_link([Pos | C], start, LastNew, true, Ws) ->
re_hash_link(C, Pos, LastNew, false, [{Pos,<<0:32>>} | Ws]);
re_hash_link([Pos | C], LastOld, LastNew, true, Ws) ->
re_hash_link(C, Pos, LastNew, false, [{Pos,<<LastOld:32>>} | Ws]);
re_hash_link([Pos | C], _LastOld, LastNew, LastInNew, Ws) ->
re_hash_link(C, Pos, LastNew, LastInNew, Ws);
re_hash_link([], _LastOld, _LastNew, _LastInNew, Ws) ->
Ws.
insert_new([{NewSlotPos,_4} | Rs], [<<P:32>> = PB | Bins], [N | Ns], Ws) ->
{FirstNew, LastNew, LastInNew} = N,
Ws1 = case P of
0 when LastInNew ->
Ws;
0 ->
[{LastNew, <<0:32>>} | Ws];
_ ->
[{LastNew, PB} | Ws]
end,
NWs = [{NewSlotPos, <<FirstNew:32>>} | Ws1],
insert_new(Rs, Bins, Ns, NWs);
insert_new([], [], [], Ws) ->
Ws.
%% When writing the cache, a 'work list' is first created:
%% WorkList = [{Key, {Delete,Lookup,[Inserted]}}]
%% Delete = keep | delete
%% Lookup = skip | lookup
%% Inserted = {object(), No}
%% No = integer()
%% If No =< 0 then there will be -No instances of object() on the file
%% when the cache has been written. If No > 0 then No instances of
%% object() will be added to the file.
%% If Delete has the value 'delete', then all objects with the key Key
%% have been deleted. (This could be viewed as a shorthand for {Object,0}
%% for each object Object on the file not mentioned in some Inserted.)
%% If Lookup has the value 'lookup', all objects with the key Key will
%% be returned.
%%
%% -> {NewHead, [LookedUpObject], pwrite_list()} | throw({NewHead, Error})
write_cache(Head) ->
#head{cache = C, type = Type} = Head,
case dets_utils:is_empty_cache(C) of
true -> {Head, [], []};
false ->
{NewC, _MaxInserts, PerKey} = dets_utils:reset_cache(C),
%% NoInsertedKeys is an upper limit on the number of new keys.
{WL, NoInsertedKeys} = make_wl(PerKey, Type),
Head1 = Head#head{cache = NewC},
case may_grow(Head1, NoInsertedKeys, once) of
{Head2, ok} ->
eval_work_list(Head2, WL);
HeadError ->
throw(HeadError)
end
end.
make_wl(PerKey, Type) ->
make_wl(PerKey, Type, [], 0).
make_wl([{Key,L} | PerKey], Type, WL, Ins) ->
[Cs | I] = wl(L, Type),
make_wl(PerKey, Type, [{Key,Cs} | WL], Ins+I);
make_wl([], _Type, WL, Ins) ->
{WL, Ins}.
wl(L, Type) ->
wl(L, Type, keep, skip, 0, []).
wl([{_Seq, delete_key} | Cs], Type, _Del, Lookup, _I, _Objs) ->
wl(Cs, Type, delete, Lookup, 0, []);
wl([{_Seq, {delete_object, Object}} | Cs], Type, Del, Lookup, I, Objs) ->
NObjs = lists:keydelete(Object, 1, Objs),
wl(Cs, Type, Del, Lookup, I, [{Object,0} | NObjs]);
wl([{_Seq, {insert, Object}} | Cs], Type, _Del, Lookup, _I, _Objs)
when Type =:= set ->
wl(Cs, Type, delete, Lookup, 1, [{Object,-1}]);
wl([{_Seq, {insert, Object}} | Cs], Type, Del, Lookup, _I, Objs) ->
NObjs =
case lists:keyfind(Object, 1, Objs) of
{_, 0} ->
lists:keyreplace(Object, 1, Objs, {Object,-1});
{_, _C} when Type =:= bag -> % C =:= 1; C =:= -1
Objs;
{_, C} when C < 0 -> % when Type =:= duplicate_bag
lists:keyreplace(Object, 1, Objs, {Object,C-1});
{_, C} -> % when C > 0, Type =:= duplicate_bag
lists:keyreplace(Object, 1, Objs, {Object,C+1});
false when Del =:= delete ->
[{Object, -1} | Objs];
false ->
[{Object, 1} | Objs]
end,
wl(Cs, Type, Del, Lookup, 1, NObjs);
wl([{_Seq, {lookup,_Pid}=Lookup} | Cs], Type, Del, _Lookup, I, Objs) ->
wl(Cs, Type, Del, Lookup, I, Objs);
wl([], _Type, Del, Lookup, I, Objs) ->
[{Del, Lookup, Objs} | I].
%% -> {NewHead, ok} | {NewHead, Error}
may_grow(Head, 0, once) ->
{Head, ok};
may_grow(Head, _N, _How) when Head#head.fixed =/= false ->
{Head, ok};
may_grow(#head{access = read}=Head, _N, _How) ->
{Head, ok};
may_grow(Head, _N, _How) when Head#head.next >= ?MAXOBJS ->
{Head, ok};
may_grow(Head, N, How) ->
Extra = erlang:min(2*?SEGSZ, Head#head.no_objects + N - Head#head.next),
case catch may_grow1(Head, Extra, How) of
{error, Reason} -> % alloc may throw error
{Head, {error, Reason}};
Reply ->
Reply
end.
may_grow1(Head, Extra, many_times) when Extra > ?SEGSZ ->
Reply = grow(Head, 1, undefined),
self() ! ?DETS_CALL(self(), may_grow),
Reply;
may_grow1(Head, Extra, _How) ->
grow(Head, Extra, undefined).
%% -> {Head, ok} | throw({Head, Error})
grow(Head, Extra, _SegZero) when Extra =< 0 ->
{Head, ok};
grow(Head, Extra, undefined) ->
grow(Head, Extra, seg_zero());
grow(Head, Extra, SegZero) ->
#head{n = N, next = Next, m = M} = Head,
SegNum = ?SLOT2SEG(Next),
{Head0, Ws1} = allocate_segment(Head, SegZero, SegNum),
{Head1, ok} = dets_utils:pwrite(Head0, Ws1),
%% If re_hash fails, segp_cache has been called, but it does not matter.
{ok, Ws2} = re_hash(Head1, N),
{Head2, ok} = dets_utils:pwrite(Head1, Ws2),
NewHead =
if
N + ?SEGSZ =:= M ->
Head2#head{n = 0, next = Next + ?SEGSZ, m = 2 * M, m2 = 4 * M};
true ->
Head2#head{n = N + ?SEGSZ, next = Next + ?SEGSZ}
end,
grow(NewHead, Extra - ?SEGSZ, SegZero).
seg_zero() ->
<<0:(4*?SEGSZ)/unit:8>>.
find_object(Head, Object) ->
Key = element(Head#head.keypos, Object),
Slot = db_hash(Key, Head),
find_object(Head, Object, Slot).
find_object(H, _Obj, Slot) when Slot >= H#head.next ->
false;
find_object(H, Obj, Slot) ->
{_Pos, Chain} = chain(H, Slot),
case catch find_obj(H, Obj, Chain) of
{ok, Pos} ->
{ok, Pos};
_Else ->
false
end.
find_obj(H, Obj, Pos) when Pos > 0 ->
{Next, _Sz, Term} = prterm(H, Pos, ?ReadAhead),
if
Term == Obj ->
{ok, Pos};
true ->
find_obj(H, Obj, Next)
end.
%% Given, a slot, return the {Pos, Chain} in the file where the
%% objects hashed to this slot reside. Pos is the position in the
%% file where the chain pointer is written and Chain is the position
%% in the file where the first object resides.
chain(Head, Slot) ->
Pos = ?SEGADDR(?SLOT2SEG(Slot)),
Segment = get_segp(Pos),
FinalPos = Segment + (4 * ?REM2(Slot, ?SEGSZ)),
{ok, <<Chain:32>>} = dets_utils:pread(Head, FinalPos, 4, 0),
{FinalPos, Chain}.
%%%
%%% Cache routines depending on the dets file format.
%%%
%% -> {Head, [LookedUpObject], pwrite_list()} | throw({Head, Error})
eval_work_list(Head, WorkLists) ->
SWLs = tag_with_slot(WorkLists, Head, []),
P1 = dets_utils:family(SWLs),
{PerSlot, SlotPositions} = remove_slot_tag(P1, [], []),
{ok, Bins} = dets_utils:pread(SlotPositions, Head),
first_object(PerSlot, SlotPositions, Bins, Head, [], [], [], []).
tag_with_slot([{K,_} = WL | WLs], Head, L) ->
tag_with_slot(WLs, Head, [{db_hash(K, Head), WL} | L]);
tag_with_slot([], _Head, L) ->
L.
remove_slot_tag([{S,SWLs} | SSWLs], Ls, SPs) ->
remove_slot_tag(SSWLs, [SWLs | Ls], [slot_position(S) | SPs]);
remove_slot_tag([], Ls, SPs) ->
{Ls, SPs}.
%% The initial chain pointers and the first object in each chain are
%% read "in parallel", that is, with one call to file:pread/2 (two
%% calls altogether). The following chain objects are read one by
%% one. This is a compromise: if the chains are long and threads are
%% active, it would be faster to keep a state for each chain and read
%% the objects of the chains in parallel, but the overhead would be
%% quite substantial.
first_object([WorkLists | SPs], [{P1,_4} | Ss], [<<P2:32>> | Bs], Head,
ObjsToRead, ToRead, Ls, LU) when P2 =:= 0 ->
L0 = [{old,P1}],
{L, NLU} = eval_slot(Head, ?ReadAhead, P2, WorkLists, L0, LU),
first_object(SPs, Ss, Bs, Head, ObjsToRead, ToRead, [L | Ls], NLU);
first_object([WorkLists | SPs], [{P1,_4} | Ss], [<<P2:32>> | Bs], Head,
ObjsToRead, ToRead, Ls, LU) ->
E = {P1,P2,WorkLists},
first_object(SPs, Ss, Bs, Head,
[E | ObjsToRead], [{P2, ?ReadAhead} | ToRead], Ls, LU);
first_object([], [], [], Head, ObjsToRead, ToRead, Ls, LU) ->
{ok, Bins} = dets_utils:pread(ToRead, Head),
case catch eval_first(Bins, ObjsToRead, Head, Ls, LU) of
{ok, NLs, NLU} ->
case create_writes(NLs, Head, [], 0) of
{Head1, [], 0} ->
{Head1, NLU, []};
{Head1, Ws, No} ->
{NewHead, Ws2} = update_no_objects(Head1, Ws, No),
{NewHead, NLU, Ws2}
end;
_Error ->
throw(dets_utils:corrupt_reason(Head, bad_object))
end.
%% Update no_objects on the file too, if the number of segments that
%% dets:fsck/6 use for estimate has changed.
update_no_objects(Head, Ws, 0) -> {Head, Ws};
update_no_objects(Head, Ws, Delta) ->
No = Head#head.no_objects,
NewNo = No + Delta,
NWs =
if
NewNo > ?MAXOBJS ->
Ws;
?SLOT2SEG(No) =:= ?SLOT2SEG(NewNo) ->
Ws;
true ->
[{?NO_OBJECTS_POS, <<NewNo:32>>} | Ws]
end,
{Head#head{no_objects = NewNo}, NWs}.
eval_first([<<Next:32, Sz:32, _Status:32, Bin/binary>> | Bins],
[SP | SPs], Head, Ls, LU) ->
{P1, P2, WLs} = SP,
L0 = [{old,P1}],
case byte_size(Bin) of
BinSz when BinSz >= Sz ->
Term = binary_to_term(Bin),
Key = element(Head#head.keypos, Term),
{L, NLU} = find_key(Head, P2, Next, Sz, Term, Key, WLs, L0, LU),
eval_first(Bins, SPs, Head, [L | Ls], NLU);
_BinSz ->
{L, NLU} = eval_slot(Head, Sz+?OHDSZ, P2, WLs, L0, LU),
eval_first(Bins, SPs, Head, [L | Ls], NLU)
end;
eval_first([], [], _Head, Ls, LU) ->
{ok, Ls, LU}.
eval_slot(_Head, _TrySize, _Pos=0, [], L, LU) ->
{L, LU};
eval_slot(Head, _TrySize, Pos=0, [WL | WLs], L, LU) ->
{_Key, {_Delete, LookUp, Objects}} = WL,
{NL, NLU} = end_of_key(Objects, LookUp, L, []),
eval_slot(Head, ?ReadAhead, Pos, WLs, NL, NLU++LU);
eval_slot(Head, TrySize, Pos, WLs, L, LU) ->
{NextPos, Size, Term} = prterm(Head, Pos, TrySize),
Key = element(Head#head.keypos, Term),
find_key(Head, Pos, NextPos, Size, Term, Key, WLs, L, LU).
find_key(Head, Pos, NextPos, Size, Term, Key, WLs, L, LU) ->
case lists:keyfind(Key, 1, WLs) of
{_, {Delete, LookUp, Objects}} = WL ->
NWLs = lists:delete(WL, WLs),
{NewObjects, NL, LUK} = eval_object(Size, Term, Delete, LookUp,
Objects, Head, Pos, L, []),
eval_key(Key, Delete, LookUp, NewObjects, Head, NextPos,
NWLs, NL, LU, LUK);
false ->
L0 = [{old,Pos} | L],
eval_slot(Head, ?ReadAhead, NextPos, WLs, L0, LU)
end.
eval_key(_Key, _Delete, Lookup, _Objects, Head, Pos, WLs, L, LU, LUK)
when Head#head.type =:= set ->
NLU = case Lookup of
{lookup, Pid} -> [{Pid,LUK} | LU];
skip -> LU
end,
eval_slot(Head, ?ReadAhead, Pos, WLs, L, NLU);
eval_key(_Key, _Delete, LookUp, Objects, Head, Pos, WLs, L, LU, LUK)
when Pos =:= 0 ->
{NL, NLU} = end_of_key(Objects, LookUp, L, LUK),
eval_slot(Head, ?ReadAhead, Pos, WLs, NL, NLU++LU);
eval_key(Key, Delete, LookUp, Objects, Head, Pos, WLs, L, LU, LUK) ->
{NextPos, Size, Term} = prterm(Head, Pos, ?ReadAhead),
case element(Head#head.keypos, Term) of
Key ->
{NewObjects, NL, LUK1} =
eval_object(Size, Term, Delete, LookUp,Objects,Head,Pos,L,LUK),
eval_key(Key, Delete, LookUp, NewObjects, Head, NextPos, WLs,
NL, LU, LUK1);
Key2 ->
{L1, NLU} = end_of_key(Objects, LookUp, L, LUK),
find_key(Head, Pos, NextPos, Size, Term, Key2, WLs, L1, NLU++LU)
end.
%% All objects in Objects have the key Key.
eval_object(Size, Term, Delete, LookUp, Objects, Head, Pos, L, LU) ->
Type = Head#head.type,
case lists:keyfind(Term, 1, Objects) of
{_Object, N} when N =:= 0 ->
L1 = [{delete,Pos,Size} | L],
{Objects, L1, LU};
{_Object, N} when N < 0, Type =:= set ->
L1 = [{old,Pos} | L],
wl_lookup(LookUp, Objects, Term, L1, LU);
{Object, _N} when Type =:= bag -> % when N =:= 1; N =:= -1
L1 = [{old,Pos} | L],
Objects1 = lists:keydelete(Object, 1, Objects),
wl_lookup(LookUp, Objects1, Term, L1, LU);
{Object, N} when N < 0, Type =:= duplicate_bag ->
L1 = [{old,Pos} | L],
Objects1 = lists:keyreplace(Object, 1, Objects, {Object,N+1}),
wl_lookup(LookUp, Objects1, Term, L1, LU);
{_Object, N} when N > 0, Type =:= duplicate_bag ->
L1 = [{old,Pos} | L],
wl_lookup(LookUp, Objects, Term, L1, LU);
false when Type =:= set, Delete =:= delete ->
case lists:keyfind(-1, 2, Objects) of
false -> % no inserted object, perhaps deleted objects
L1 = [{delete,Pos,Size} | L],
{[], L1, LU};
{Term2, -1} ->
Bin2 = term_to_binary(Term2),
NSize = byte_size(Bin2),
Overwrite =
if
NSize =:= Size ->
true;
true ->
SizePos = sz2pos(Size+?OHDSZ),
NSizePos = sz2pos(NSize+?OHDSZ),
SizePos =:= NSizePos
end,
E = if
Overwrite ->
{overwrite,Bin2,Pos};
true ->
{replace,Bin2,Pos,Size}
end,
wl_lookup(LookUp, [], Term2, [E | L], LU)
end;
false when Delete =:= delete ->
L1 = [{delete,Pos,Size} | L],
{Objects, L1, LU};
false ->
L1 = [{old,Pos} | L],
wl_lookup(LookUp, Objects, Term, L1, LU)
end.
%% Inlined.
wl_lookup({lookup,_}, Objects, Term, L, LU) ->
{Objects, L, [Term | LU]};
wl_lookup(skip, Objects, _Term, L, LU) ->
{Objects, L, LU}.
end_of_key([{Object,N0} | Objs], LookUp, L, LU) when N0 =/= 0 ->
N = abs(N0),
NL = [{insert,N,term_to_binary(Object)} | L],
NLU = case LookUp of
{lookup, _} ->
lists:duplicate(N, Object) ++ LU;
skip ->
LU
end,
end_of_key(Objs, LookUp, NL, NLU);
end_of_key([_ | Objects], LookUp, L, LU) ->
end_of_key(Objects, LookUp, L, LU);
end_of_key([], {lookup,Pid}, L, LU) ->
{L, [{Pid,LU}]};
end_of_key([], skip, L, LU) ->
{L, LU}.
create_writes([L | Ls], H, Ws, No) ->
{NH, NWs, NNo} = create_writes(L, H, Ws, No, 0, true),
create_writes(Ls, NH, NWs, NNo);
create_writes([], H, Ws, No) ->
{H, lists:reverse(Ws), No}.
create_writes([{old,Pos} | L], H, Ws, No, _Next, true) ->
create_writes(L, H, Ws, No, Pos, true);
create_writes([{old,Pos} | L], H, Ws, No, Next, false) ->
W = {Pos, <<Next:32>>},
create_writes(L, H, [W | Ws], No, Pos, true);
create_writes([{insert,N,Bin} | L], H, Ws, No, Next, _NextIsOld) ->
{NH, NWs, Pos} = create_inserts(N, H, Ws, Next, byte_size(Bin), Bin),
create_writes(L, NH, NWs, No+N, Pos, false);
create_writes([{overwrite,Bin,Pos} | L], H, Ws, No, Next, _) ->
Size = byte_size(Bin),
W = {Pos, [<<Next:32, Size:32, ?ACTIVE:32>>, Bin]},
create_writes(L, H, [W | Ws], No, Pos, true);
create_writes([{replace,Bin,Pos,OSize} | L], H, Ws, No, Next, _) ->
Size = byte_size(Bin),
{H1, _} = dets_utils:free(H, Pos, OSize+?OHDSZ),
{NH, NewPos, _} = dets_utils:alloc(H1, ?OHDSZ + Size),
W1 = {NewPos, [<<Next:32, Size:32, ?ACTIVE:32>>, Bin]},
NWs = if
Pos =:= NewPos ->
[W1 | Ws];
true ->
W2 = {Pos+?STATUS_POS, <<?FREE:32>>},
[W1,W2 | Ws]
end,
create_writes(L, NH, NWs, No, NewPos, false);
create_writes([{delete,Pos,Size} | L], H, Ws, No, Next, _) ->
{NH, _} = dets_utils:free(H, Pos, Size+?OHDSZ),
NWs = [{Pos+?STATUS_POS,<<?FREE:32>>} | Ws],
create_writes(L, NH, NWs, No-1, Next, false);
create_writes([], H, Ws, No, _Next, _NextIsOld) ->
{H, Ws, No}.
create_inserts(0, H, Ws, Next, _Size, _Bin) ->
{H, Ws, Next};
create_inserts(N, H, Ws, Next, Size, Bin) ->
{NH, Pos, _} = dets_utils:alloc(H, ?OHDSZ + Size),
W = {Pos, [<<Next:32, Size:32, ?ACTIVE:32>>, Bin]},
create_inserts(N-1, NH, [W | Ws], Pos, Size, Bin).
slot_position(S) ->
Pos = ?SEGADDR(?SLOT2SEG(S)),
Segment = get_segp(Pos),
FinalPos = Segment + (4 * ?REM2(S, ?SEGSZ)),
{FinalPos, 4}.
%% Twice the size of a segment due to the bug in sz2pos/1. Inlined.
actual_seg_size() ->
?POW(sz2pos(?SEGSZ*4)-1).
segp_cache(Pos, Segment) ->
put(Pos, Segment).
%% Inlined.
get_segp(Pos) ->
get(Pos).
%% Bug: If Sz0 is equal to 2**k for some k, then 2**(k+1) bytes are
%% allocated (wasting 2**k bytes).
sz2pos(N) ->
1 + dets_utils:log2(N+1).
scan_objs(_Head, Bin, From, To, L, Ts, R, _Type) ->
scan_objs(Bin, From, To, L, Ts, R).
scan_objs(Bin, From, To, L, Ts, -1) ->
{stop, Bin, From, To, L, Ts};
scan_objs(B = <<_N:32, Sz:32, St:32, T/binary>>, From, To, L, Ts, R) ->
if
St =:= ?ACTIVE;
St =:= ?FREE -> % deleted after scanning started
case T of
<<BinTerm:Sz/binary, T2/binary>> ->
NTs = [BinTerm | Ts],
OSz = Sz + ?OHDSZ,
Skip = ?POW(sz2pos(OSz)-1) - OSz,
F2 = From + OSz,
NR = if
R < 0 ->
R + 1;
true ->
R + OSz + Skip
end,
scan_skip(T2, F2, To, Skip, L, NTs, NR);
_ ->
{more, From, To, L, Ts, R, Sz+?OHDSZ}
end;
true -> % a segment
scan_skip(B, From, To, actual_seg_size(), L, Ts, R)
end;
scan_objs(_B, From, To, L, Ts, R) ->
{more, From, To, L, Ts, R, 0}.
scan_skip(Bin, From, To, Skip, L, Ts, R) when From + Skip < To ->
SkipPos = From + Skip,
case Bin of
<<_:Skip/binary, Tail/binary>> ->
scan_objs(Tail, SkipPos, To, L, Ts, R);
_ ->
{more, SkipPos, To, L, Ts, R, 0}
end;
scan_skip(Bin, From, To, Skip, L, Ts, R) when From + Skip =:= To ->
scan_next_allocated(Bin, From, To, L, Ts, R);
scan_skip(_Bin, From, _To, Skip, L, Ts, R) -> % when From + Skip > _To
From1 = From + Skip,
{more, From1, From1, L, Ts, R, 0}.
scan_next_allocated(_Bin, _From, To, <<>>=L, Ts, R) ->
{more, To, To, L, Ts, R, 0};
scan_next_allocated(Bin, From0, _To, <<From:32, To:32, L/binary>>, Ts, R) ->
Skip = From - From0,
scan_skip(Bin, From0, To, Skip, L, Ts, R).
%% Read term from file at position Pos
prterm(Head, Pos, ReadAhead) ->
Res = dets_utils:pread(Head, Pos, ?OHDSZ, ReadAhead),
?DEBUGF("file:pread(~tp, ~p, ?) -> ~p~n", [Head#head.filename, Pos, Res]),
{ok, <<Next:32, Sz:32, _Status:32, Bin0/binary>>} = Res,
?DEBUGF("{Next, Sz} = ~p~n", [{Next, Sz}]),
Bin = case byte_size(Bin0) of
Actual when Actual >= Sz ->
Bin0;
_ ->
{ok, Bin1} = dets_utils:pread(Head, Pos + ?OHDSZ, Sz, 0),
Bin1
end,
Term = binary_to_term(Bin),
{Next, Sz, Term}.
%%%%%%%%%%%%%%%%% DEBUG functions %%%%%%%%%%%%%%%%
file_info(FH) ->
#fileheader{closed_properly = CP, keypos = Kp,
m = M, next = Next, n = N, version = Version,
type = Type, no_objects = NoObjects}
= FH,
if
CP =:= 0 ->
{error, not_closed};
FH#fileheader.cookie =/= ?MAGIC ->
{error, not_a_dets_file};
FH#fileheader.version =/= ?FILE_FORMAT_VERSION ->
{error, bad_version};
true ->
{ok, [{closed_properly,CP},{keypos,Kp},{m, M},
{n,N},{next,Next},{no_objects,NoObjects},
{type,Type},{version,Version}]}
end.
v_segments(H) ->
v_segments(H, 0).
v_segments(_H, ?SEGARRSZ) ->
done;
v_segments(H, SegNo) ->
Seg = dets_utils:read_4(H#head.fptr, ?SEGADDR(SegNo)),
if
Seg =:= 0 ->
done;
true ->
io:format("SEGMENT ~w ", [SegNo]),
io:format("At position ~w~n", [Seg]),
v_segment(H, SegNo, Seg, 0),
v_segments(H, SegNo+1)
end.
v_segment(_H, _, _SegPos, ?SEGSZ) ->
done;
v_segment(H, SegNo, SegPos, SegSlot) ->
Slot = SegSlot + (SegNo * ?SEGSZ),
Chain = dets_utils:read_4(H#head.fptr, SegPos + (4 * SegSlot)),
if
Chain =:= 0 -> %% don't print empty chains
true;
true ->
io:format(" <~p>~p: [",[SegPos + (4 * SegSlot), Slot]),
print_chain(H, Chain)
end,
v_segment(H, SegNo, SegPos, SegSlot+1).
print_chain(_H, 0) ->
io:format("] \n", []);
print_chain(H, Pos) ->
{ok, _} = file:position(H#head.fptr, Pos),
case rterm(H#head.fptr) of
{ok, 0, _Sz, Term} ->
io:format("<~p>~p] \n",[Pos, Term]);
{ok, Next, _Sz, Term} ->
io:format("<~p>~p, ", [Pos, Term]),
print_chain(H, Next);
Other ->
io:format("~nERROR ~p~n", [Other])
end.
%% Can't be used at the bucket level!!!!
%% Only when we go down a chain
rterm(F) ->
case catch rterm2(F) of
{'EXIT', Reason} -> %% truncated DAT file
dets_utils:vformat("** dets: Corrupt or truncated dets file~n",
[]),
{error, Reason};
Other ->
Other
end.
rterm2(F) ->
{ok, <<Next:32, Sz:32, _:32>>} = file:read(F, ?OHDSZ),
{ok, Bin} = file:read(F, Sz),
Term = binary_to_term(Bin),
{ok, Next, Sz, Term}.
