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      1 // Protocol Buffers - Google's data interchange format
      2 // Copyright 2008 Google Inc.  All rights reserved.
      3 // https://developers.google.com/protocol-buffers/
      4 //
      5 // Redistribution and use in source and binary forms, with or without
      6 // modification, are permitted provided that the following conditions are
      7 // met:
      8 //
      9 //     * Redistributions of source code must retain the above copyright
     10 // notice, this list of conditions and the following disclaimer.
     11 //     * Redistributions in binary form must reproduce the above
     12 // copyright notice, this list of conditions and the following disclaimer
     13 // in the documentation and/or other materials provided with the
     14 // distribution.
     15 //     * Neither the name of Google Inc. nor the names of its
     16 // contributors may be used to endorse or promote products derived from
     17 // this software without specific prior written permission.
     18 //
     19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     30 
     31 syntax = "proto3";
     32 
     33 package google.protobuf;
     34 
     35 option csharp_namespace = "Google.Protobuf.WellKnownTypes";
     36 option java_package = "com.google.protobuf";
     37 option java_outer_classname = "FieldMaskProto";
     38 option java_multiple_files = true;
     39 option objc_class_prefix = "GPB";
     40 option java_generate_equals_and_hash = true;
     41 
     42 // `FieldMask` represents a set of symbolic field paths, for example:
     43 //
     44 //     paths: "f.a"
     45 //     paths: "f.b.d"
     46 //
     47 // Here `f` represents a field in some root message, `a` and `b`
     48 // fields in the message found in `f`, and `d` a field found in the
     49 // message in `f.b`.
     50 //
     51 // Field masks are used to specify a subset of fields that should be
     52 // returned by a get operation or modified by an update operation.
     53 // Field masks also have a custom JSON encoding (see below).
     54 //
     55 // # Field Masks in Projections
     56 //
     57 // When used in the context of a projection, a response message or
     58 // sub-message is filtered by the API to only contain those fields as
     59 // specified in the mask. For example, if the mask in the previous
     60 // example is applied to a response message as follows:
     61 //
     62 //     f {
     63 //       a : 22
     64 //       b {
     65 //         d : 1
     66 //         x : 2
     67 //       }
     68 //       y : 13
     69 //     }
     70 //     z: 8
     71 //
     72 // The result will not contain specific values for fields x,y and z
     73 // (their value will be set to the default, and omitted in proto text
     74 // output):
     75 //
     76 //
     77 //     f {
     78 //       a : 22
     79 //       b {
     80 //         d : 1
     81 //       }
     82 //     }
     83 //
     84 // A repeated field is not allowed except at the last position of a
     85 // field mask.
     86 //
     87 // If a FieldMask object is not present in a get operation, the
     88 // operation applies to all fields (as if a FieldMask of all fields
     89 // had been specified).
     90 //
     91 // Note that a field mask does not necessarily apply to the
     92 // top-level response message. In case of a REST get operation, the
     93 // field mask applies directly to the response, but in case of a REST
     94 // list operation, the mask instead applies to each individual message
     95 // in the returned resource list. In case of a REST custom method,
     96 // other definitions may be used. Where the mask applies will be
     97 // clearly documented together with its declaration in the API.  In
     98 // any case, the effect on the returned resource/resources is required
     99 // behavior for APIs.
    100 //
    101 // # Field Masks in Update Operations
    102 //
    103 // A field mask in update operations specifies which fields of the
    104 // targeted resource are going to be updated. The API is required
    105 // to only change the values of the fields as specified in the mask
    106 // and leave the others untouched. If a resource is passed in to
    107 // describe the updated values, the API ignores the values of all
    108 // fields not covered by the mask.
    109 //
    110 // In order to reset a field's value to the default, the field must
    111 // be in the mask and set to the default value in the provided resource.
    112 // Hence, in order to reset all fields of a resource, provide a default
    113 // instance of the resource and set all fields in the mask, or do
    114 // not provide a mask as described below.
    115 //
    116 // If a field mask is not present on update, the operation applies to
    117 // all fields (as if a field mask of all fields has been specified).
    118 // Note that in the presence of schema evolution, this may mean that
    119 // fields the client does not know and has therefore not filled into
    120 // the request will be reset to their default. If this is unwanted
    121 // behavior, a specific service may require a client to always specify
    122 // a field mask, producing an error if not.
    123 //
    124 // As with get operations, the location of the resource which
    125 // describes the updated values in the request message depends on the
    126 // operation kind. In any case, the effect of the field mask is
    127 // required to be honored by the API.
    128 //
    129 // ## Considerations for HTTP REST
    130 //
    131 // The HTTP kind of an update operation which uses a field mask must
    132 // be set to PATCH instead of PUT in order to satisfy HTTP semantics
    133 // (PUT must only be used for full updates).
    134 //
    135 // # JSON Encoding of Field Masks
    136 //
    137 // In JSON, a field mask is encoded as a single string where paths are
    138 // separated by a comma. Fields name in each path are converted
    139 // to/from lower-camel naming conventions.
    140 //
    141 // As an example, consider the following message declarations:
    142 //
    143 //     message Profile {
    144 //       User user = 1;
    145 //       Photo photo = 2;
    146 //     }
    147 //     message User {
    148 //       string display_name = 1;
    149 //       string address = 2;
    150 //     }
    151 //
    152 // In proto a field mask for `Profile` may look as such:
    153 //
    154 //     mask {
    155 //       paths: "user.display_name"
    156 //       paths: "photo"
    157 //     }
    158 //
    159 // In JSON, the same mask is represented as below:
    160 //
    161 //     {
    162 //       mask: "user.displayName,photo"
    163 //     }
    164 //
    165 // # Field Masks and Oneof Fields
    166 //
    167 // Field masks treat fields in oneofs just as regular fields. Consider the
    168 // following message:
    169 //
    170 //     message SampleMessage {
    171 //       oneof test_oneof {
    172 //         string name = 4;
    173 //         SubMessage sub_message = 9;
    174 //       }
    175 //     }
    176 //
    177 // The field mask can be:
    178 //
    179 //     mask {
    180 //       paths: "name"
    181 //     }
    182 //
    183 // Or:
    184 //
    185 //     mask {
    186 //       paths: "sub_message"
    187 //     }
    188 //
    189 // Note that oneof type names ("test_oneof" in this case) cannot be used in
    190 // paths.
    191 message FieldMask {
    192   // The set of field mask paths.
    193   repeated string paths = 1;
    194 }
    195