86 lines
3.5 KiB
OCaml
86 lines
3.5 KiB
OCaml
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(*----------------------------------------------------------------------------
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Copyright (c) 2016 Inhabited Type LLC.
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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3. Neither the name of the author nor the names of his contributors
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may be used to endorse or promote products derived from this software
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without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND ANY EXPRESS
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OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
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ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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----------------------------------------------------------------------------*)
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open Angstrom.Unbuffered
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open Core
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open Async
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let empty_bigstring = Bigstring.create 0
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let rec finalize state result =
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(* It is very important to understand the assumptions that go into the second
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* case. If execution reaches that case, then that means that the parser has
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* commited all the way up to the last byte that was read by the reader, and
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* the reader's internal buffer is empty. If the parser hadn't committed up
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* to the last byte, then the reader buffer would not be empty and execution
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* would hit the first case rather than the second.
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*
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* In other words, the second case looks wrong but it's not. *)
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match state, result with
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| Partial p, `Eof_with_unconsumed_data s ->
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let bigstring = Bigstring.of_string s in
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finalize (p.continue bigstring ~off:0 ~len:(String.length s) Complete) `Eof
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| Partial p, `Eof ->
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finalize (p.continue empty_bigstring ~off:0 ~len:0 Complete) `Eof
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| Partial _, `Stopped () -> assert false
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| (Done _ | Fail _) , _ -> state_to_result state
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let response = function
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| Partial p -> `Consumed(p.committed, `Need_unknown)
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| Done(c, _) -> `Stop_consumed((), c)
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| Fail _ -> `Stop ()
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let default_pushback () = Deferred.unit
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let parse ?(pushback=default_pushback) p reader =
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let state = ref (parse p) in
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let handle_chunk buf ~pos ~len =
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begin match !state with
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| Partial p ->
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state := p.continue buf ~off:pos ~len Incomplete;
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| Done _ | Fail _ -> ()
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end;
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pushback () >>| fun () -> response !state
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in
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Reader.read_one_chunk_at_a_time reader ~handle_chunk >>| fun result ->
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finalize !state result
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let async_many e k =
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Angstrom.(skip_many (e <* commit >>| k) <?> "async_many")
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let parse_many p write reader =
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let wait = ref (default_pushback ()) in
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let k x = wait := write x in
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let pushback () = !wait in
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parse ~pushback (async_many p k) reader
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