Struct FieldMask 

pub struct FieldMask {
    pub paths: Vec<String>,
    /* private fields */
}

FieldMask represents a set of symbolic field paths, for example:

paths: "f.a"
paths: "f.b.d"

Here f represents a field in some root message, a and b fields in the message found in f, and d a field found in the message in f.b.

Field masks are used to specify a subset of fields that should be returned by a get operation or modified by an update operation. Field masks also have a custom JSON encoding (see below).

Field Masks in Projections

When used in the context of a projection, a response message or sub-message is filtered by the API to only contain those fields as specified in the mask. For example, if the mask in the previous example is applied to a response message as follows:

f {
  a : 22
  b {
    d : 1
    x : 2
  }
  y : 13
}
z: 8

The result will not contain specific values for fields x,y and z (their value will be set to the default, and omitted in proto text output):

f {
  a : 22
  b {
    d : 1
  }
}

A repeated field is not allowed except at the last position of a paths string.

If a FieldMask object is not present in a get operation, the operation applies to all fields (as if a FieldMask of all fields had been specified).

Note that a field mask does not necessarily apply to the top-level response message. In case of a REST get operation, the field mask applies directly to the response, but in case of a REST list operation, the mask instead applies to each individual message in the returned resource list. In case of a REST custom method, other definitions may be used. Where the mask applies will be clearly documented together with its declaration in the API. In any case, the effect on the returned resource/resources is required behavior for APIs.

Field Masks in Update Operations

A field mask in update operations specifies which fields of the targeted resource are going to be updated. The API is required to only change the values of the fields as specified in the mask and leave the others untouched. If a resource is passed in to describe the updated values, the API ignores the values of all fields not covered by the mask.

If a repeated field is specified for an update operation, new values will be appended to the existing repeated field in the target resource. Note that a repeated field is only allowed in the last position of a paths string.

If a sub-message is specified in the last position of the field mask for an update operation, then new value will be merged into the existing sub-message in the target resource.

For example, given the target message:

f {
  b {
    d: 1
    x: 2
  }
  c: [1]
}

And an update message:

f {
  b {
    d: 10
  }
  c: [2]
}

then if the field mask is:

paths: [“f.b”, “f.c”]

then the result will be:

f {
  b {
    d: 10
    x: 2
  }
  c: [1, 2]
}

An implementation may provide options to override this default behavior for repeated and message fields.

In order to reset a field’s value to the default, the field must be in the mask and set to the default value in the provided resource. Hence, in order to reset all fields of a resource, provide a default instance of the resource and set all fields in the mask, or do not provide a mask as described below.

If a field mask is not present on update, the operation applies to all fields (as if a field mask of all fields has been specified). Note that in the presence of schema evolution, this may mean that fields the client does not know and has therefore not filled into the request will be reset to their default. If this is unwanted behavior, a specific service may require a client to always specify a field mask, producing an error if not.

As with get operations, the location of the resource which describes the updated values in the request message depends on the operation kind. In any case, the effect of the field mask is required to be honored by the API.

Considerations for HTTP REST

The HTTP kind of an update operation which uses a field mask must be set to PATCH instead of PUT in order to satisfy HTTP semantics (PUT must only be used for full updates).

JSON Encoding of Field Masks

In JSON, a field mask is encoded as a single string where paths are separated by a comma. Fields name in each path are converted to/from lower-camel naming conventions.

As an example, consider the following message declarations:

message Profile {
  User user = 1;
  Photo photo = 2;
}
message User {
  string display_name = 1;
  string address = 2;
}

In proto a field mask for Profile may look as such:

mask {
  paths: "user.display_name"
  paths: "photo"
}

In JSON, the same mask is represented as below:

{
  mask: "user.displayName,photo"
}

Field Masks and Oneof Fields

Field masks treat fields in oneofs just as regular fields. Consider the following message:

message SampleMessage {
  oneof test_oneof {
    string name = 4;
    SubMessage sub_message = 9;
  }
}

The field mask can be:

mask {
  paths: "name"
}

Or:

mask {
  paths: "sub_message"
}

Note that oneof type names (“test_oneof” in this case) cannot be used in paths.

Field Mask Verification

The implementation of any API method which has a FieldMask type field in the request should verify the included field paths, and return an INVALID_ARGUMENT error if any path is unmappable.

Fields

paths: Vec<String>

The set of field mask paths.

Field 1: paths

Implementations

impl FieldMask

pub fn from_paths(paths: impl IntoIterator<Item = impl Into<String>>) -> Self

Create a FieldMask from an iterator of field paths.

Example

use buffa_types::google::protobuf::FieldMask;

let mask = FieldMask::from_paths(["user.name", "user.email"]);
assert!(mask.contains("user.name"));

pub fn contains(&self, path: &str) -> bool

Returns true if path is present in this field mask.

Comparison is exact (case-sensitive, no wildcard expansion). Runs in O(n) time where n is the number of paths.

pub fn len(&self) -> usize

Returns the number of paths in the field mask.

pub fn is_empty(&self) -> bool

Returns true if the field mask contains no paths.

pub fn iter(&self) -> Iter<'_, String>

Returns an iterator over the paths in the field mask.

impl FieldMask

pub const TYPE_URL: &'static str = "type.googleapis.com/google.protobuf.FieldMask"

Protobuf type URL for this message, for use with Any::pack and Any::unpack_if.

Format: type.googleapis.com/<fully.qualified.TypeName>

Trait Implementations

impl<'arbitrary> Arbitrary<'arbitrary> for FieldMask

fn arbitrary(u: &mut Unstructured<'arbitrary>) -> Result<Self>

Generate an arbitrary value of Self from the given unstructured data.

fn arbitrary_take_rest(u: Unstructured<'arbitrary>) -> Result<Self>

Generate an arbitrary value of Self from the entirety of the given unstructured data.

fn size_hint(depth: usize) -> (usize, Option<usize>)

Get a size hint for how many bytes out of an Unstructured this type needs to construct itself.

fn try_size_hint( depth: usize, ) -> Result<(usize, Option<usize>), MaxRecursionReached>

Get a size hint for how many bytes out of an Unstructured this type needs to construct itself.

impl Clone for FieldMask

fn clone(&self) -> FieldMask

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FieldMask

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for FieldMask

fn default() -> FieldMask

Returns the “default value” for a type.

impl DefaultInstance for FieldMask

fn default_instance() -> &'static Self

Return a reference to the single default instance of this type.

impl<'de> Deserialize<'de> for FieldMask

Available on crate feature json only.

fn deserialize<D: Deserializer<'de>>(d: D) -> Result<Self, D::Error>

Deserializes from a comma-separated string of lowerCamelCase field paths.

Errors

Returns an error if any path component contains an underscore, which is invalid in the lowerCamelCase JSON representation.

impl ExtensionSet for FieldMask

const PROTO_FQN: &'static str = "google.protobuf.FieldMask"

Fully-qualified proto type name of this message (no leading dot), e.g. "google.protobuf.FieldOptions".

fn unknown_fields(&self) -> &UnknownFields

Immutable access to the extendee’s unknown-field storage.

fn unknown_fields_mut(&mut self) -> &mut UnknownFields

Mutable access to the extendee’s unknown-field storage.

fn extension<C>(&self, ext: &Extension<C>) -> <C as ExtensionCodec>::Output

where C: ExtensionCodec,

Read an extension value.

fn set_extension<C>( &mut self, ext: &Extension<C>, value: <C as ExtensionCodec>::Value, )

where C: ExtensionCodec,

Write an extension value, replacing any prior occurrences.

fn has_extension<C>(&self, ext: &Extension<C>) -> bool

where C: ExtensionCodec,

Returns true if any record at the extension’s field number is present.

fn clear_extension<C>(&mut self, ext: &Extension<C>)

where C: ExtensionCodec,

Remove all records at the extension’s field number.

fn extension_or_default<C>( &self, ext: &Extension<C>, ) -> <C as ExtensionCodec>::Value

where C: ExtensionCodec<Output = Option<<C as ExtensionCodec>::Value>>, <C as ExtensionCodec>::Value: Default,

Read a singular extension value, returning the proto2 [default = ...] value if absent, or the type’s Default if no proto default was declared.

impl<'a> IntoIterator for &'a FieldMask

type Item = &'a String

The type of the elements being iterated over.

type IntoIter = Iter<'a, String>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl IntoIterator for FieldMask

type Item = String

The type of the elements being iterated over.

type IntoIter = IntoIter<String>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl Message for FieldMask

fn compute_size(&self) -> u32

Returns the total encoded size in bytes.

The result is a u32; the protobuf specification requires all messages to fit within 2 GiB (2,147,483,647 bytes), so a compliant message will never overflow this type.

fn write_to(&self, buf: &mut impl BufMut)

Write this message’s encoded bytes to a buffer.

fn merge_field( &mut self, tag: Tag, buf: &mut impl Buf, depth: u32, ) -> Result<(), DecodeError>

Processes a single already-decoded tag and its associated field data from buf.

fn cached_size(&self) -> u32

The cached encoded size from the last compute_size() call.

fn clear(&mut self)

Clear all fields to their default values.

fn encode(&self, buf: &mut impl BufMut)

Convenience: compute size, then write. This is the primary encoding API.

fn encode_length_delimited(&self, buf: &mut impl BufMut)

Encode this message as a length-delimited byte sequence.

fn encode_to_vec(&self) -> Vec<u8>

Encode this message to a new Vec<u8>.

fn encode_to_bytes(&self) -> Bytes

Encode this message to a new bytes::Bytes.

fn decode(buf: &mut impl Buf) -> Result<Self, DecodeError>

where Self: Sized,

Decode a message from a buffer.

fn decode_from_slice(data: &[u8]) -> Result<Self, DecodeError>

where Self: Sized,

Decode a message from a byte slice.

fn decode_length_delimited(buf: &mut impl Buf) -> Result<Self, DecodeError>

where Self: Sized,

Decode a length-delimited message from a buffer.

fn merge_to_limit( &mut self, buf: &mut impl Buf, depth: u32, limit: usize, ) -> Result<(), DecodeError>

Merge fields from a buffer until buf.remaining() reaches limit.

fn merge_group( &mut self, buf: &mut impl Buf, depth: u32, field_number: u32, ) -> Result<(), DecodeError>

Merges a group-encoded message from buf, reading fields until an EndGroup tag with the given field_number is encountered.

fn merge(&mut self, buf: &mut impl Buf, depth: u32) -> Result<(), DecodeError>

Merge fields from a buffer into this message.

fn merge_from_slice(&mut self, data: &[u8]) -> Result<(), DecodeError>

Merge fields from a byte slice into this message.

fn merge_length_delimited( &mut self, buf: &mut impl Buf, depth: u32, ) -> Result<(), DecodeError>

Merge fields from a length-delimited sub-message payload into this message.

impl PartialEq for FieldMask

fn eq(&self, other: &FieldMask) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for FieldMask

Available on crate feature json only.

fn serialize<S: Serializer>(&self, s: S) -> Result<S::Ok, S::Error>

Serializes as a comma-separated string of lowerCamelCase field paths.

Errors

Returns an error if any path cannot round-trip through camelCase conversion (e.g. paths that are already camelCase, contain consecutive underscores, or have digits immediately after underscores).

impl TextFormat for FieldMask

fn encode_text(&self, enc: &mut TextEncoder<'_>) -> Result

Write this message’s fields to enc.

fn merge_text(&mut self, dec: &mut TextDecoder<'_>) -> Result<(), ParseError>

Merge fields from dec into this message.

impl StructuralPartialEq for FieldMask