ceph/src/jaegertracing/thrift/doc/specs/thrift-protocol-spec.md

   1 Thrift Protocol Structure
   2 ====================================================================
   3
   4 Last Modified: 2007-Jun-29
   5
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  26 --------------------------------------------------------------------
  27 -->
  28
  29 This document describes the structure of the Thrift protocol
  30 without specifying the encoding. Thus, the order of elements
  31 could in some cases be rearranged depending upon the TProtocol
  32 implementation, but this document specifies the minimum required
  33 structure. There are some "dumb" terminals like STRING and INT
  34 that take the place of an actual encoding specification.
  35
  36 They key point to notice is that ALL messages are just one wrapped
  37 `<struct>`. Depending upon the message type, the `<struct>` can be
  38 interpreted as the argument list to a function, the return value
  39 of a function, or an exception.
  40
  41 --------------------------------------------------------------------
  42
  43 ```
  44        <message> ::= <message-begin> <struct> <message-end>
  45
  46  <message-begin> ::= <method-name> <message-type> <message-seqid>
  47
  48    <method-name> ::= STRING
  49
  50   <message-type> ::= T_CALL | T_REPLY | T_EXCEPTION | T_ONEWAY
  51
  52  <message-seqid> ::= I32
  53
  54         <struct> ::= <struct-begin> <field>* <field-stop> <struct-end>
  55
  56   <struct-begin> ::= <struct-name>
  57
  58    <struct-name> ::= STRING
  59
  60     <field-stop> ::= T_STOP
  61
  62          <field> ::= <field-begin> <field-data> <field-end>
  63
  64    <field-begin> ::= <field-name> <field-type> <field-id>
  65
  66     <field-name> ::= STRING
  67
  68     <field-type> ::= T_BOOL | T_BYTE | T_I8 | T_I16 | T_I32 | T_I64 | T_DOUBLE
  69                      | T_STRING | T_BINARY | T_STRUCT | T_MAP | T_SET | T_LIST
  70
  71       <field-id> ::= I16
  72
  73     <field-data> ::= I8 | I16 | I32 | I64 | DOUBLE | STRING | BINARY
  74                      <struct> | <map> | <list> | <set>
  75
  76            <map> ::= <map-begin> <field-datum>* <map-end>
  77
  78      <map-begin> ::= <map-key-type> <map-value-type> <map-size>
  79
  80   <map-key-type> ::= <field-type>
  81
  82 <map-value-type> ::= <field-type>
  83
  84       <map-size> ::= I32
  85
  86           <list> ::= <list-begin> <field-data>* <list-end>
  87
  88     <list-begin> ::= <list-elem-type> <list-size>
  89
  90 <list-elem-type> ::= <field-type>
  91
  92      <list-size> ::= I32
  93
  94            <set> ::= <set-begin> <field-data>* <set-end>
  95
  96      <set-begin> ::= <set-elem-type> <set-size>
  97
  98  <set-elem-type> ::= <field-type>
  99
 100       <set-size> ::= I32
 101 ```