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% Licensed under the Apache License, Version 2.0 (the "License"); you may not
% use this file except in compliance with the License. You may obtain a copy of
% the License at
%
% http://www.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
% License for the specific language governing permissions and limitations under
% the License.
-module(smoosh_priority_queue).
-export([new/1, recover/1]).
-export([last_updated/2, is_key/2, in/4, in/5, out/1, size/1, info/1]).
-export([flush/1]).
-export([from_list/2, to_list/1]).
-export([is_empty/1]).
-export([file_name/1, write_to_file/1]).
-define(VSN, 1).
-record(priority_queue, {
name,
map,
tree
}).
new(Name) ->
#priority_queue{name = Name, map = maps:new(), tree = gb_trees:empty()}.
recover(#priority_queue{name = Name, map = Map0} = Q) ->
case do_recover(file_name(Q)) of
{ok, Terms} ->
Map = maps:merge(Map0, Terms),
Tree = maps:fold(
fun(Key, {TreeKey, Value}, TreeAcc) ->
gb_trees:enter(TreeKey, {Key, Value}, TreeAcc)
end,
gb_trees:empty(),
Map
),
#priority_queue{name = Name, map = Map, tree = Tree};
error ->
Q
end.
write_to_file(#priority_queue{map = Map} = Q) ->
smoosh_utils:write_to_file(Map, file_name(Q), ?VSN).
flush(#priority_queue{name = Name} = Q) ->
Q#priority_queue{name = Name, map = maps:new(), tree = gb_trees:empty()}.
last_updated(Key, #priority_queue{map = Map}) ->
case maps:find(Key, Map) of
{ok, {_Priority, {LastUpdatedMTime, _MInt}}} ->
LastUpdatedMTime;
error ->
false
end.
is_key(Key, #priority_queue{map = Map}) ->
maps:is_key(Key, Map).
in(Key, Value, Priority, Q) ->
in(Key, Value, Priority, infinity, Q).
in(Key, Value, Priority, Capacity, #priority_queue{name = Name, map = Map, tree = Tree}) ->
Tree1 =
case maps:find(Key, Map) of
{ok, TreeKey} ->
gb_trees:delete_any(TreeKey, Tree);
error ->
Tree
end,
Now = {erlang:monotonic_time(), erlang:unique_integer([monotonic])},
TreeKey1 = {Priority, Now},
Tree2 = gb_trees:enter(TreeKey1, {Key, Value}, Tree1),
Map1 = maps:put(Key, TreeKey1, Map),
truncate(Capacity, #priority_queue{name = Name, map = Map1, tree = Tree2}).
out(#priority_queue{name = Name, map = Map, tree = Tree}) ->
case gb_trees:is_empty(Tree) of
true ->
false;
false ->
{_, {Key, Value}, Tree1} = gb_trees:take_largest(Tree),
Map1 = maps:remove(Key, Map),
Q = #priority_queue{name = Name, map = Map1, tree = Tree1},
{Key, Value, Q}
end.
size(#priority_queue{tree = Tree}) ->
gb_trees:size(Tree).
info(#priority_queue{tree = Tree} = Q) ->
[
{size, ?MODULE:size(Q)}
| case gb_trees:is_empty(Tree) of
true ->
[];
false ->
{Min, _, _} = gb_trees:take_smallest(Tree),
{Max, _, _} = gb_trees:take_largest(Tree),
[{min, Min}, {max, Max}]
end
].
from_list(Orddict, #priority_queue{name = Name}) ->
Map = maps:from_list(Orddict),
Tree = gb_trees:from_orddict(Orddict),
#priority_queue{name = Name, map = Map, tree = Tree}.
to_list(#priority_queue{tree = Tree}) ->
gb_trees:to_list(Tree).
is_empty(#priority_queue{tree = Tree}) ->
gb_trees:is_empty(Tree).
file_name(#priority_queue{name = Name}) ->
filename:join(config:get("smoosh", "state_dir", "."), Name ++ ".waiting").
truncate(infinity, Q) ->
Q;
truncate(Capacity, Q) when Capacity > 0 ->
truncate(Capacity, ?MODULE:size(Q), Q).
truncate(Capacity, Size, Q) when Size =< Capacity ->
Q;
truncate(Capacity, Size, #priority_queue{name = Name, map = Map, tree = Tree}) when Size > 0 ->
{_, {Key, _}, Tree1} = gb_trees:take_smallest(Tree),
Q1 = #priority_queue{name = Name, map = maps:remove(Key, Map), tree = Tree1},
truncate(Capacity, ?MODULE:size(Q1), Q1).
do_recover(FilePath) ->
case file:read_file(FilePath) of
{ok, Content} ->
<<Vsn, Binary/binary>> = Content,
try parse_queue(Vsn, ?VSN, Binary) of
Bin ->
Level = smoosh_utils:log_level("compaction_log_level", "debug"),
couch_log:Level(
"~p Successfully restored state file ~s", [?MODULE, FilePath]
),
{ok, Bin}
catch
error:Reason ->
couch_log:error(
"~p Invalid queue file (~p). Deleting ~s", [?MODULE, Reason, FilePath]
),
file:delete(FilePath),
error
end;
{error, enoent} ->
Level = smoosh_utils:log_level("compaction_log_level", "debug"),
couch_log:Level(
"~p (~p) Queue file ~s does not exist. Not restoring.", [?MODULE, enoent, FilePath]
),
error;
{error, Reason} ->
couch_log:error(
"~p Cannot read the queue file (~p). Deleting ~s", [?MODULE, Reason, FilePath]
),
file:delete(FilePath),
error
end.
parse_queue(1, ?VSN, Binary) ->
erlang:binary_to_term(Binary, [safe]);
parse_queue(Vsn, ?VSN, _) ->
error({unsupported_version, Vsn}).
|
