165 lines
4.1 KiB
Erlang
165 lines
4.1 KiB
Erlang
%%%----------------------------------------------------------------------
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%%% File : xml_stream.erl
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%%% Author : Alexey Shchepin <alexey@sevcom.net>
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%%% Purpose : Parse XML streams
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%%% Created : 17 Nov 2002 by Alexey Shchepin <alexey@sevcom.net>
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%%% Id : $Id$
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%%%----------------------------------------------------------------------
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-module(xml_stream).
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-author('alexey@sevcom.net').
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-vsn('$Revision$ ').
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-export([new/1,
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new/2,
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parse/2,
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close/1,
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parse_element/1]).
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-define(XML_START, 0).
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-define(XML_END, 1).
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-define(XML_CDATA, 2).
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-define(XML_ERROR, 3).
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-define(PARSE_COMMAND, 0).
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-define(PARSE_FINAL_COMMAND, 1).
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-record(xml_stream_state, {callback_pid, port, stack, size, maxsize}).
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process_data(CallbackPid, Stack, Data) ->
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case Data of
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{?XML_START, {Name, Attrs}} ->
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if
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Stack == [] ->
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catch gen_fsm:send_event(CallbackPid,
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{xmlstreamstart, Name, Attrs});
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true ->
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ok
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end,
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[{xmlelement, Name, Attrs, []} | Stack];
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{?XML_END, EndName} ->
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case Stack of
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[{xmlelement, Name, Attrs, Els} | Tail] ->
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NewEl = {xmlelement, Name, Attrs, lists:reverse(Els)},
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case Tail of
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[] ->
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catch gen_fsm:send_event(CallbackPid,
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{xmlstreamend, EndName}),
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Tail;
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[_] ->
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catch gen_fsm:send_event(CallbackPid,
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{xmlstreamelement, NewEl}),
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Tail;
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[{xmlelement, Name1, Attrs1, Els1} | Tail1] ->
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[{xmlelement, Name1, Attrs1, [NewEl | Els1]} |
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Tail1]
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end
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end;
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{?XML_CDATA, CData} ->
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case Stack of
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[El] ->
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[El];
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[{xmlelement, Name, Attrs, Els} | Tail] ->
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[{xmlelement, Name, Attrs, [{xmlcdata, CData} | Els]} |
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Tail];
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[] -> []
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end;
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{?XML_ERROR, Err} ->
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catch gen_fsm:send_event(CallbackPid, {xmlstreamerror, Err})
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end.
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new(CallbackPid) ->
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new(CallbackPid, infinity).
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new(CallbackPid, MaxSize) ->
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Port = open_port({spawn, expat_erl}, [binary]),
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#xml_stream_state{callback_pid = CallbackPid,
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port = Port,
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stack = [],
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size = 0,
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maxsize = MaxSize}.
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parse(#xml_stream_state{callback_pid = CallbackPid,
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port = Port,
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stack = Stack,
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size = Size,
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maxsize = MaxSize} = State, Str) ->
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StrSize = if
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is_list(Str) -> length(Str);
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is_binary(Str) -> size(Str)
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end,
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Res = port_control(Port, ?PARSE_COMMAND, Str),
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{NewStack, NewSize} =
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lists:foldl(
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fun(Data, {St, Sz}) ->
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NewSt = process_data(CallbackPid, St, Data),
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case NewSt of
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[_] -> {NewSt, 0};
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_ -> {NewSt, Sz}
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end
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end, {Stack, Size + StrSize}, binary_to_term(Res)),
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if
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NewSize > MaxSize ->
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catch gen_fsm:send_event(CallbackPid,
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{xmlstreamerror, "XML stanza is too big"});
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true ->
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ok
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end,
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State#xml_stream_state{stack = NewStack, size = NewSize}.
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close(#xml_stream_state{port = Port}) ->
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port_close(Port).
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parse_element(Str) ->
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Port = open_port({spawn, expat_erl}, [binary]),
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Res = port_control(Port, ?PARSE_FINAL_COMMAND, Str),
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port_close(Port),
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process_element_events(binary_to_term(Res)).
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process_element_events(Events) ->
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process_element_events(Events, []).
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process_element_events([], _Stack) ->
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{error, parse_error};
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process_element_events([Event | Events], Stack) ->
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case Event of
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{?XML_START, {Name, Attrs}} ->
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process_element_events(
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Events, [{xmlelement, Name, Attrs, []} | Stack]);
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{?XML_END, _EndName} ->
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case Stack of
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[{xmlelement, Name, Attrs, Els} | Tail] ->
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NewEl = {xmlelement, Name, Attrs, lists:reverse(Els)},
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case Tail of
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[] ->
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if
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Events == [] ->
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NewEl;
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true ->
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{error, parse_error}
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end;
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[{xmlelement, Name1, Attrs1, Els1} | Tail1] ->
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process_element_events(
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Events,
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[{xmlelement, Name1, Attrs1, [NewEl | Els1]} |
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Tail1])
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end
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end;
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{?XML_CDATA, CData} ->
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case Stack of
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[{xmlelement, Name, Attrs, Els} | Tail] ->
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process_element_events(
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Events,
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[{xmlelement, Name, Attrs, [{xmlcdata, CData} | Els]} |
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Tail]);
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[] ->
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process_element_events(Events, [])
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end;
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{?XML_ERROR, Err} ->
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{error, Err}
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end.
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