thrift.bnf

   1 Thrift Protocol Structure
   2
   3 Mark Slee (mcslee@facebook.com)
   4
   5 Last Modified: 2007-Jun-29
   6
   7 Thrift is distributed under the Thrift open source software license.
   8 Please see the included LICENSE file.
   9
  10 --------------------------------------------------------------------
  11
  12 This document describes the structure of the Thrift protocol
  13 without specifying the encoding. Thus, the order of elements
  14 could in some cases be rearranged depending upon the TProtocol
  15 implementation, but this document specifies the minimum required
  16 structure. There are some "dumb" terminals like STRING and INT
  17 that take the place of an actual encoding specification.
  18
  19 They key point to notice is that ALL messages are just one wrapped
  20 <struct>. Depending upon the message type, the <struct> can be
  21 interpreted as the argument list to a function, the return value
  22 of a function, or an exception.
  23
  24 --------------------------------------------------------------------
  25
  26        <message> ::= <message-begin> <struct> <message-end>
  27
  28  <message-begin> ::= <method-name> <message-type> <message-seqid>
  29
  30    <method-name> ::= STRING
  31
  32   <message-type> ::= T_CALL | T_REPLY | T_EXCEPTION
  33
  34  <message-seqid> ::= I32
  35
  36         <struct> ::= <struct-begin> <field>* <field-stop> <struct-end>
  37
  38   <struct-begin> ::= <struct-name>
  39
  40    <struct-name> ::= STRING
  41
  42     <field-stop> ::= T_STOP
  43
  44          <field> ::= <field-begin> <field-data> <field-end>
  45
  46    <field-begin> ::= <field-name> <field-type> <field-id>
  47
  48     <field-name> ::= STRING
  49
  50     <field-type> ::= T_BOOL | T_BYTE | T_I8 | T_I16 | T_I32 | T_I64 | T_DOUBLE
  51                      | T_STRING | T_STRUCT | T_MAP | T_SET | T_LIST
  52
  53       <field-id> ::= I16
  54
  55     <field-data> ::= I8 | I16 | I32 | I64 | DOUBLE | STRING |
  56                      <struct> | <map> | <list> | <set>
  57
  58            <map> ::= <map-begin> <field-datum>* <map-end>
  59
  60      <map-begin> ::= <map-key-type> <map-value-type> <map-size>
  61
  62   <map-key-type> ::= <field-type>
  63
  64 <map-value-type> ::= <field-type>
  65
  66       <map-size> ::= I32
  67
  68           <list> ::= <list-begin> <field-data>* <list-end>
  69
  70     <list-begin> ::= <list-elem-type> <list-size>
  71
  72 <list-elem-type> ::= <field-type>
  73
  74      <list-size> ::= I32
  75
  76            <set> ::= <set-begin> <field-data>* <set-end>
  77
  78      <set-begin> ::= <set-elem-type> <set-size>
  79
  80  <set-elem-type> ::= <field-type>
  81
  82       <set-size> ::= I32