lib/erl/src/thrift_transport.erl

%%
%% Licensed to the Apache Software Foundation (ASF) under one
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%% distributed with this work for additional information
%% regarding copyright ownership. The ASF licenses this file
%% to you 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
%%
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%% 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(thrift_transport).

-export([behaviour_info/1]).
%% constructors
-export([new/1, new/2]).
%% transport callbacks
-export([read/2, read_exact/2, write/2, flush/1, close/1]).

-export_type([t_transport/0]).


behaviour_info(callbacks) ->
  [{read, 2}, {write, 2}, {flush, 1}, {close, 1}].


-record(t_transport, {
  module,
  state
}).

-type state() :: #t_transport{}.
-type t_transport() :: #t_transport{}.


-ifdef(transport_wrapper_module).
-define(debug_wrap(Transport),
  case Transport#t_transport.module of
    ?transport_wrapper_module -> Transport;
    _Else ->
      {ok, Result} = ?transport_wrapper_module:new(Transport),
      Result
  end
).
-else.
-define(debug_wrap(Transport), Transport).
-endif.


-type wrappable() ::
  binary() |
  list() |
  {membuffer, binary() | list()} |
  {tcp, port()} |
  {tcp, port(), list()} |
  {file, file:io_device()} |
  {file, file:io_device(), list()} |
  {file, file:filename()} |
  {file, file:filename(), list()}.

-spec new(wrappable()) -> {ok, #t_transport{}}.

new({membuffer, Membuffer}) when is_binary(Membuffer); is_list(Membuffer) ->
  thrift_membuffer_transport:new(Membuffer);
new({membuffer, Membuffer, []}) when is_binary(Membuffer); is_list(Membuffer) ->
  thrift_membuffer_transport:new(Membuffer);
new({tcp, Socket}) when is_port(Socket) ->
  new({tcp, Socket, []});
new({tcp, Socket, Opts}) when is_port(Socket) ->
  thrift_socket_transport:new(Socket, Opts);
new({file, Filename}) when is_list(Filename); is_binary(Filename) ->
  new({file, Filename, []});
new({file, Filename, Opts}) when is_list(Filename); is_binary(Filename) ->
  {ok, File} = file:open(Filename, [raw, binary]),
  new({file, File, Opts});
new({file, File, Opts}) ->
  thrift_file_transport:new(File, Opts).

-spec new(Module::module(), State::any()) -> {ok, #t_transport{}}.

new(Module, State) when is_atom(Module) ->
  {ok, ?debug_wrap(#t_transport{module = Module, state = State})}.


-include("thrift_transport_behaviour.hrl").


read(Transport = #t_transport{module = Module}, Len)
when is_integer(Len), Len >= 0 ->
  {NewState, Result} = Module:read(Transport#t_transport.state, Len),
  {Transport#t_transport{state = NewState}, Result}.


read_exact(Transport = #t_transport{module = Module}, Len)
when is_integer(Len), Len >= 0 ->
  case lists:keyfind(read_exact, 1, Module:module_info(exports)) of
    {read_exact, 2} ->
      {NewState, Result} = Module:read_exact(Transport#t_transport.state, Len),
      {Transport#t_transport{state = NewState}, Result};
    _ ->
      read(Transport, Len)
  end.


write(Transport = #t_transport{module = Module}, Data) ->
  {NewState, Result} = Module:write(Transport#t_transport.state, Data),
  {Transport#t_transport{state = NewState}, Result}.


flush(Transport = #t_transport{module = Module}) ->
  {NewState, Result} = Module:flush(Transport#t_transport.state),
  {Transport#t_transport{state = NewState}, Result}.


close(Transport = #t_transport{module = Module}) ->
  {NewState, Result} = Module:close(Transport#t_transport.state),
  {Transport#t_transport{state = NewState}, Result}.