kpt-grpc-demo/google/cloud/documentai/v1/document.proto

// Copyright 2022 Google LLC
//
// Licensed 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
//
// Unless required by applicable law or agreed to in writing, 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.

syntax = "proto3";

package google.cloud.documentai.v1;

import "google/api/field_behavior.proto";
import "google/cloud/documentai/v1/barcode.proto";
import "google/cloud/documentai/v1/geometry.proto";
import "google/protobuf/timestamp.proto";
import "google/rpc/status.proto";
import "google/type/color.proto";
import "google/type/date.proto";
import "google/type/datetime.proto";
import "google/type/money.proto";
import "google/type/postal_address.proto";

option csharp_namespace = "Google.Cloud.DocumentAI.V1";
option go_package = "google.golang.org/genproto/googleapis/cloud/documentai/v1;documentai";
option java_multiple_files = true;
option java_outer_classname = "DocumentProto";
option java_package = "com.google.cloud.documentai.v1";
option php_namespace = "Google\\Cloud\\DocumentAI\\V1";
option ruby_package = "Google::Cloud::DocumentAI::V1";

// Document represents the canonical document resource in Document AI. It is an
// interchange format that provides insights into documents and allows for
// collaboration between users and Document AI to iterate and optimize for
// quality.
message Document {
  // For a large document, sharding may be performed to produce several
  // document shards. Each document shard contains this field to detail which
  // shard it is.
  message ShardInfo {
    // The 0-based index of this shard.
    int64 shard_index = 1;

    // Total number of shards.
    int64 shard_count = 2;

    // The index of the first character in [Document.text][google.cloud.documentai.v1.Document.text] in the overall
    // document global text.
    int64 text_offset = 3;
  }

  // Annotation for common text style attributes. This adheres to CSS
  // conventions as much as possible.
  message Style {
    // Font size with unit.
    message FontSize {
      // Font size for the text.
      float size = 1;

      // Unit for the font size. Follows CSS naming (in, px, pt, etc.).
      string unit = 2;
    }

    // Text anchor indexing into the [Document.text][google.cloud.documentai.v1.Document.text].
    TextAnchor text_anchor = 1;

    // Text color.
    google.type.Color color = 2;

    // Text background color.
    google.type.Color background_color = 3;

    // Font weight. Possible values are normal, bold, bolder, and lighter.
    // https://www.w3schools.com/cssref/pr_font_weight.asp
    string font_weight = 4;

    // Text style. Possible values are normal, italic, and oblique.
    // https://www.w3schools.com/cssref/pr_font_font-style.asp
    string text_style = 5;

    // Text decoration. Follows CSS standard.
    // <text-decoration-line> <text-decoration-color> <text-decoration-style>
    // https://www.w3schools.com/cssref/pr_text_text-decoration.asp
    string text_decoration = 6;

    // Font size.
    FontSize font_size = 7;

    // Font family such as `Arial`, `Times New Roman`.
    // https://www.w3schools.com/cssref/pr_font_font-family.asp
    string font_family = 8;
  }

  // A page in a [Document][google.cloud.documentai.v1.Document].
  message Page {
    // Dimension for the page.
    message Dimension {
      // Page width.
      float width = 1;

      // Page height.
      float height = 2;

      // Dimension unit.
      string unit = 3;
    }

    // Rendered image contents for this page.
    message Image {
      // Raw byte content of the image.
      bytes content = 1;

      // Encoding mime type for the image.
      string mime_type = 2;

      // Width of the image in pixels.
      int32 width = 3;

      // Height of the image in pixels.
      int32 height = 4;
    }

    // Representation for transformation matrix, intended to be compatible and
    // used with OpenCV format for image manipulation.
    message Matrix {
      // Number of rows in the matrix.
      int32 rows = 1;

      // Number of columns in the matrix.
      int32 cols = 2;

      // This encodes information about what data type the matrix uses.
      // For example, 0 (CV_8U) is an unsigned 8-bit image. For the full list
      // of OpenCV primitive data types, please refer to
      // https://docs.opencv.org/4.3.0/d1/d1b/group__core__hal__interface.html
      int32 type = 3;

      // The matrix data.
      bytes data = 4;
    }

    // Visual element describing a layout unit on a page.
    message Layout {
      // Detected human reading orientation.
      enum Orientation {
        // Unspecified orientation.
        ORIENTATION_UNSPECIFIED = 0;

        // Orientation is aligned with page up.
        PAGE_UP = 1;

        // Orientation is aligned with page right.
        // Turn the head 90 degrees clockwise from upright to read.
        PAGE_RIGHT = 2;

        // Orientation is aligned with page down.
        // Turn the head 180 degrees from upright to read.
        PAGE_DOWN = 3;

        // Orientation is aligned with page left.
        // Turn the head 90 degrees counterclockwise from upright to read.
        PAGE_LEFT = 4;
      }

      // Text anchor indexing into the [Document.text][google.cloud.documentai.v1.Document.text].
      TextAnchor text_anchor = 1;

      // Confidence of the current [Layout][google.cloud.documentai.v1.Document.Page.Layout] within context of the object this
      // layout is for. e.g. confidence can be for a single token, a table,
      // a visual element, etc. depending on context. Range `[0, 1]`.
      float confidence = 2;

      // The bounding polygon for the [Layout][google.cloud.documentai.v1.Document.Page.Layout].
      BoundingPoly bounding_poly = 3;

      // Detected orientation for the [Layout][google.cloud.documentai.v1.Document.Page.Layout].
      Orientation orientation = 4;
    }

    // A block has a set of lines (collected into paragraphs) that have a
    // common line-spacing and orientation.
    message Block {
      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [Block][google.cloud.documentai.v1.Document.Page.Block].
      Layout layout = 1;

      // A list of detected languages together with confidence.
      repeated DetectedLanguage detected_languages = 2;

      // The history of this annotation.
      Provenance provenance = 3 [deprecated = true];
    }

    // A collection of lines that a human would perceive as a paragraph.
    message Paragraph {
      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [Paragraph][google.cloud.documentai.v1.Document.Page.Paragraph].
      Layout layout = 1;

      // A list of detected languages together with confidence.
      repeated DetectedLanguage detected_languages = 2;

      // The  history of this annotation.
      Provenance provenance = 3 [deprecated = true];
    }

    // A collection of tokens that a human would perceive as a line.
    // Does not cross column boundaries, can be horizontal, vertical, etc.
    message Line {
      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [Line][google.cloud.documentai.v1.Document.Page.Line].
      Layout layout = 1;

      // A list of detected languages together with confidence.
      repeated DetectedLanguage detected_languages = 2;

      // The  history of this annotation.
      Provenance provenance = 3 [deprecated = true];
    }

    // A detected token.
    message Token {
      // Detected break at the end of a [Token][google.cloud.documentai.v1.Document.Page.Token].
      message DetectedBreak {
        // Enum to denote the type of break found.
        enum Type {
          // Unspecified break type.
          TYPE_UNSPECIFIED = 0;

          // A single whitespace.
          SPACE = 1;

          // A wider whitespace.
          WIDE_SPACE = 2;

          // A hyphen that indicates that a token has been split across lines.
          HYPHEN = 3;
        }

        // Detected break type.
        Type type = 1;
      }

      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [Token][google.cloud.documentai.v1.Document.Page.Token].
      Layout layout = 1;

      // Detected break at the end of a [Token][google.cloud.documentai.v1.Document.Page.Token].
      DetectedBreak detected_break = 2;

      // A list of detected languages together with confidence.
      repeated DetectedLanguage detected_languages = 3;

      // The history of this annotation.
      Provenance provenance = 4 [deprecated = true];
    }

    // A detected symbol.
    message Symbol {
      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [Symbol][google.cloud.documentai.v1.Document.Page.Symbol].
      Layout layout = 1;

      // A list of detected languages together with confidence.
      repeated DetectedLanguage detected_languages = 2;
    }

    // Detected non-text visual elements e.g. checkbox, signature etc. on the
    // page.
    message VisualElement {
      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [VisualElement][google.cloud.documentai.v1.Document.Page.VisualElement].
      Layout layout = 1;

      // Type of the [VisualElement][google.cloud.documentai.v1.Document.Page.VisualElement].
      string type = 2;

      // A list of detected languages together with confidence.
      repeated DetectedLanguage detected_languages = 3;
    }

    // A table representation similar to HTML table structure.
    message Table {
      // A row of table cells.
      message TableRow {
        // Cells that make up this row.
        repeated TableCell cells = 1;
      }

      // A cell representation inside the table.
      message TableCell {
        // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [TableCell][google.cloud.documentai.v1.Document.Page.Table.TableCell].
        Layout layout = 1;

        // How many rows this cell spans.
        int32 row_span = 2;

        // How many columns this cell spans.
        int32 col_span = 3;

        // A list of detected languages together with confidence.
        repeated DetectedLanguage detected_languages = 4;
      }

      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [Table][google.cloud.documentai.v1.Document.Page.Table].
      Layout layout = 1;

      // Header rows of the table.
      repeated TableRow header_rows = 2;

      // Body rows of the table.
      repeated TableRow body_rows = 3;

      // A list of detected languages together with confidence.
      repeated DetectedLanguage detected_languages = 4;

      // The history of this table.
      Provenance provenance = 5;
    }

    // A form field detected on the page.
    message FormField {
      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for the [FormField][google.cloud.documentai.v1.Document.Page.FormField] name. e.g. `Address`, `Email`,
      // `Grand total`, `Phone number`, etc.
      Layout field_name = 1;

      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for the [FormField][google.cloud.documentai.v1.Document.Page.FormField] value.
      Layout field_value = 2;

      // A list of detected languages for name together with confidence.
      repeated DetectedLanguage name_detected_languages = 3;

      // A list of detected languages for value together with confidence.
      repeated DetectedLanguage value_detected_languages = 4;

      // If the value is non-textual, this field represents the type. Current
      // valid values are:
      // - blank (this indicates the field_value is normal text)
      // - "unfilled_checkbox"
      // - "filled_checkbox"
      string value_type = 5;

      // Created for Labeling UI to export key text.
      // If corrections were made to the text identified by the
      // `field_name.text_anchor`, this field will contain the correction.
      string corrected_key_text = 6;

      // Created for Labeling UI to export value text.
      // If corrections were made to the text identified by the
      // `field_value.text_anchor`, this field will contain the correction.
      string corrected_value_text = 7;

      // The history of this annotation.
      Provenance provenance = 8;
    }

    // A detected barcode.
    message DetectedBarcode {
      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [DetectedBarcode][google.cloud.documentai.v1.Document.Page.DetectedBarcode].
      Layout layout = 1;

      // Detailed barcode information of the [DetectedBarcode][google.cloud.documentai.v1.Document.Page.DetectedBarcode].
      Barcode barcode = 2;
    }

    // Detected language for a structural component.
    message DetectedLanguage {
      // The BCP-47 language code, such as `en-US` or `sr-Latn`. For more
      // information, see
      // https://www.unicode.org/reports/tr35/#Unicode_locale_identifier.
      string language_code = 1;

      // Confidence of detected language. Range `[0, 1]`.
      float confidence = 2;
    }

    // Image Quality Scores for the page image
    message ImageQualityScores {
      // Image Quality Defects
      message DetectedDefect {
        // Name of the defect type. Supported values are:
        //
        // - `quality/defect_blurry`
        // - `quality/defect_noisy`
        // - `quality/defect_dark`
        // - `quality/defect_faint`
        // - `quality/defect_text_too_small`
        // - `quality/defect_document_cutoff`
        // - `quality/defect_text_cutoff`
        // - `quality/defect_glare`
        string type = 1;

        // Confidence of detected defect. Range `[0, 1]` where 1 indicates
        // strong confidence of that the defect exists.
        float confidence = 2;
      }

      // The overall quality score. Range `[0, 1]` where 1 is perfect quality.
      float quality_score = 1;

      // A list of detected defects.
      repeated DetectedDefect detected_defects = 2;
    }

    // 1-based index for current [Page][google.cloud.documentai.v1.Document.Page] in a parent [Document][google.cloud.documentai.v1.Document].
    // Useful when a page is taken out of a [Document][google.cloud.documentai.v1.Document] for individual
    // processing.
    int32 page_number = 1;

    // Rendered image for this page. This image is preprocessed to remove any
    // skew, rotation, and distortions such that the annotation bounding boxes
    // can be upright and axis-aligned.
    Image image = 13;

    // Transformation matrices that were applied to the original document image
    // to produce [Page.image][google.cloud.documentai.v1.Document.Page.image].
    repeated Matrix transforms = 14;

    // Physical dimension of the page.
    Dimension dimension = 2;

    // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for the page.
    Layout layout = 3;

    // A list of detected languages together with confidence.
    repeated DetectedLanguage detected_languages = 4;

    // A list of visually detected text blocks on the page.
    // A block has a set of lines (collected into paragraphs) that have a common
    // line-spacing and orientation.
    repeated Block blocks = 5;

    // A list of visually detected text paragraphs on the page.
    // A collection of lines that a human would perceive as a paragraph.
    repeated Paragraph paragraphs = 6;

    // A list of visually detected text lines on the page.
    // A collection of tokens that a human would perceive as a line.
    repeated Line lines = 7;

    // A list of visually detected tokens on the page.
    repeated Token tokens = 8;

    // A list of detected non-text visual elements e.g. checkbox,
    // signature etc. on the page.
    repeated VisualElement visual_elements = 9;

    // A list of visually detected tables on the page.
    repeated Table tables = 10;

    // A list of visually detected form fields on the page.
    repeated FormField form_fields = 11;

    // A list of visually detected symbols on the page.
    repeated Symbol symbols = 12;

    // A list of detected barcodes.
    repeated DetectedBarcode detected_barcodes = 15;

    // Image Quality Scores.
    ImageQualityScores image_quality_scores = 17;

    // The history of this page.
    Provenance provenance = 16 [deprecated = true];
  }

  // An entity that could be a phrase in the text or a property that belongs to
  // the document. It is a known entity type, such as a person, an organization,
  // or location.
  message Entity {
    // Parsed and normalized entity value.
    message NormalizedValue {
      // An optional structured entity value.
      // Must match entity type defined in schema if
      // known. If this field is present, the `text` field could also be
      // populated.
      oneof structured_value {
        // Money value. See also:
        // https://github.com/googleapis/googleapis/blob/master/google/type/money.proto
        google.type.Money money_value = 2;

        // Date value. Includes year, month, day. See also:
        // https://github.com/googleapis/googleapis/blob/master/google/type/date.proto
        google.type.Date date_value = 3;

        // DateTime value. Includes date, time, and timezone. See also:
        // https://github.com/googleapis/googleapis/blob/master/google/type/datetime.proto
        google.type.DateTime datetime_value = 4;

        // Postal address. See also:
        // https://github.com/googleapis/googleapis/blob/master/google/type/postal_address.proto
        google.type.PostalAddress address_value = 5;

        // Boolean value. Can be used for entities with binary values, or for
        // checkboxes.
        bool boolean_value = 6;

        // Integer value.
        int32 integer_value = 7;

        // Float value.
        float float_value = 8;
      }

      // Optional. An optional field to store a normalized string.
      // For some entity types, one of respective `structured_value` fields may
      // also be populated. Also not all the types of `structured_value` will be
      // normalized. For example, some processors may not generate float
      // or int normalized text by default.
      //
      // Below are sample formats mapped to structured values.
      //
      // - Money/Currency type (`money_value`) is in the ISO 4217 text format.
      // - Date type (`date_value`) is in the ISO 8601 text format.
      // - Datetime type (`datetime_value`) is in the ISO 8601 text format.
      string text = 1 [(google.api.field_behavior) = OPTIONAL];
    }

    // Optional. Provenance of the entity.
    // Text anchor indexing into the [Document.text][google.cloud.documentai.v1.Document.text].
    TextAnchor text_anchor = 1 [(google.api.field_behavior) = OPTIONAL];

    // Required. Entity type from a schema e.g. `Address`.
    string type = 2 [(google.api.field_behavior) = REQUIRED];

    // Optional. Text value of the entity e.g. `1600 Amphitheatre Pkwy`.
    string mention_text = 3 [(google.api.field_behavior) = OPTIONAL];

    // Optional. Deprecated.  Use `id` field instead.
    string mention_id = 4 [(google.api.field_behavior) = OPTIONAL];

    // Optional. Confidence of detected Schema entity. Range `[0, 1]`.
    float confidence = 5 [(google.api.field_behavior) = OPTIONAL];

    // Optional. Represents the provenance of this entity wrt. the location on the
    // page where it was found.
    PageAnchor page_anchor = 6 [(google.api.field_behavior) = OPTIONAL];

    // Optional. Canonical id. This will be a unique value in the entity list
    // for this document.
    string id = 7 [(google.api.field_behavior) = OPTIONAL];

    // Optional. Normalized entity value. Absent if the extracted value could not be
    // converted or the type (e.g. address) is not supported for certain
    // parsers. This field is also only populated for certain supported document
    // types.
    NormalizedValue normalized_value = 9 [(google.api.field_behavior) = OPTIONAL];

    // Optional. Entities can be nested to form a hierarchical data structure representing
    // the content in the document.
    repeated Entity properties = 10 [(google.api.field_behavior) = OPTIONAL];

    // Optional. The history of this annotation.
    Provenance provenance = 11 [(google.api.field_behavior) = OPTIONAL];

    // Optional. Whether the entity will be redacted for de-identification purposes.
    bool redacted = 12 [(google.api.field_behavior) = OPTIONAL];
  }

  // Relationship between [Entities][google.cloud.documentai.v1.Document.Entity].
  message EntityRelation {
    // Subject entity id.
    string subject_id = 1;

    // Object entity id.
    string object_id = 2;

    // Relationship description.
    string relation = 3;
  }

  // Text reference indexing into the [Document.text][google.cloud.documentai.v1.Document.text].
  message TextAnchor {
    // A text segment in the [Document.text][google.cloud.documentai.v1.Document.text]. The indices may be out of bounds
    // which indicate that the text extends into another document shard for
    // large sharded documents. See [ShardInfo.text_offset][google.cloud.documentai.v1.Document.ShardInfo.text_offset]
    message TextSegment {
      // [TextSegment][google.cloud.documentai.v1.Document.TextAnchor.TextSegment] start UTF-8 char index in the [Document.text][google.cloud.documentai.v1.Document.text].
      int64 start_index = 1;

      // [TextSegment][google.cloud.documentai.v1.Document.TextAnchor.TextSegment] half open end UTF-8 char index in the
      // [Document.text][google.cloud.documentai.v1.Document.text].
      int64 end_index = 2;
    }

    // The text segments from the [Document.text][google.cloud.documentai.v1.Document.text].
    repeated TextSegment text_segments = 1;

    // Contains the content of the text span so that users do
    // not have to look it up in the text_segments.  It is always
    // populated for formFields.
    string content = 2;
  }

  // Referencing the visual context of the entity in the [Document.pages][google.cloud.documentai.v1.Document.pages].
  // Page anchors can be cross-page, consist of multiple bounding polygons and
  // optionally reference specific layout element types.
  message PageAnchor {
    // Represents a weak reference to a page element within a document.
    message PageRef {
      // The type of layout that is being referenced.
      enum LayoutType {
        // Layout Unspecified.
        LAYOUT_TYPE_UNSPECIFIED = 0;

        // References a [Page.blocks][google.cloud.documentai.v1.Document.Page.blocks] element.
        BLOCK = 1;

        // References a [Page.paragraphs][google.cloud.documentai.v1.Document.Page.paragraphs] element.
        PARAGRAPH = 2;

        // References a [Page.lines][google.cloud.documentai.v1.Document.Page.lines] element.
        LINE = 3;

        // References a [Page.tokens][google.cloud.documentai.v1.Document.Page.tokens] element.
        TOKEN = 4;

        // References a [Page.visual_elements][google.cloud.documentai.v1.Document.Page.visual_elements] element.
        VISUAL_ELEMENT = 5;

        // Refrrences a [Page.tables][google.cloud.documentai.v1.Document.Page.tables] element.
        TABLE = 6;

        // References a [Page.form_fields][google.cloud.documentai.v1.Document.Page.form_fields] element.
        FORM_FIELD = 7;
      }

      // Required. Index into the [Document.pages][google.cloud.documentai.v1.Document.pages] element, for example using
      // [Document.pages][page_refs.page] to locate the related page element.
      // This field is skipped when its value is the default 0. See
      // https://developers.google.com/protocol-buffers/docs/proto3#json.
      int64 page = 1 [(google.api.field_behavior) = REQUIRED];

      // Optional. The type of the layout element that is being referenced if any.
      LayoutType layout_type = 2 [(google.api.field_behavior) = OPTIONAL];

      // Optional. Deprecated.  Use [PageRef.bounding_poly][google.cloud.documentai.v1.Document.PageAnchor.PageRef.bounding_poly] instead.
      string layout_id = 3 [
        deprecated = true,
        (google.api.field_behavior) = OPTIONAL
      ];

      // Optional. Identifies the bounding polygon of a layout element on the page.
      BoundingPoly bounding_poly = 4 [(google.api.field_behavior) = OPTIONAL];

      // Optional. Confidence of detected page element, if applicable. Range `[0, 1]`.
      float confidence = 5 [(google.api.field_behavior) = OPTIONAL];
    }

    // One or more references to visual page elements
    repeated PageRef page_refs = 1;
  }

  // Structure to identify provenance relationships between annotations in
  // different revisions.
  message Provenance {
    // The parent element the current element is based on. Used for
    // referencing/aligning, removal and replacement operations.
    message Parent {
      // The index of the index into current revision's parent_ids list.
      int32 revision = 1;

      // The index of the parent item in the corresponding item list (eg. list
      // of entities, properties within entities, etc.) in the parent revision.
      int32 index = 3;

      // The id of the parent provenance.
      int32 id = 2 [deprecated = true];
    }

    // If a processor or agent does an explicit operation on existing elements.
    enum OperationType {
      // Operation type unspecified. If no operation is specified a provenance
      // entry is simply used to match against a `parent`.
      OPERATION_TYPE_UNSPECIFIED = 0;

      // Add an element.
      ADD = 1;

      // Remove an element identified by `parent`.
      REMOVE = 2;

      // Replace an element identified by `parent`.
      REPLACE = 3;

      // Request human review for the element identified by `parent`.
      EVAL_REQUESTED = 4;

      // Element is reviewed and approved at human review, confidence will be
      // set to 1.0.
      EVAL_APPROVED = 5;

      // Element is skipped in the validation process.
      EVAL_SKIPPED = 6;
    }

    // The index of the revision that produced this element.
    int32 revision = 1;

    // The Id of this operation.  Needs to be unique within the scope of the
    // revision.
    int32 id = 2 [deprecated = true];

    // References to the original elements that are replaced.
    repeated Parent parents = 3;

    // The type of provenance operation.
    OperationType type = 4;
  }

  // Contains past or forward revisions of this document.
  message Revision {
    // Human Review information of the document.
    message HumanReview {
      // Human review state. e.g. `requested`, `succeeded`, `rejected`.
      string state = 1;

      // A message providing more details about the current state of processing.
      // For example, the rejection reason when the state is `rejected`.
      string state_message = 2;
    }

    // Who/what made the change
    oneof source {
      // If the change was made by a person specify the name or id of that
      // person.
      string agent = 4;

      // If the annotation was made by processor identify the processor by its
      // resource name.
      string processor = 5;
    }

    // Id of the revision.  Unique within the context of the document.
    string id = 1;

    // The revisions that this revision is based on.  This can include one or
    // more parent (when documents are merged.)  This field represents the
    // index into the `revisions` field.
    repeated int32 parent = 2 [deprecated = true];

    // The revisions that this revision is based on. Must include all the ids
    // that have anything to do with this revision - eg. there are
    // `provenance.parent.revision` fields that index into this field.
    repeated string parent_ids = 7;

    // The time that the revision was created.
    google.protobuf.Timestamp create_time = 3;

    // Human Review information of this revision.
    HumanReview human_review = 6;
  }

  // This message is used for text changes aka. OCR corrections.
  message TextChange {
    // Provenance of the correction.
    // Text anchor indexing into the [Document.text][google.cloud.documentai.v1.Document.text].  There can only be a
    // single `TextAnchor.text_segments` element.  If the start and
    // end index of the text segment are the same, the text change is inserted
    // before that index.
    TextAnchor text_anchor = 1;

    // The text that replaces the text identified in the `text_anchor`.
    string changed_text = 2;

    // The history of this annotation.
    repeated Provenance provenance = 3 [deprecated = true];
  }

  // Original source document from the user.
  oneof source {
    // Optional. Currently supports Google Cloud Storage URI of the form
    //    `gs://bucket_name/object_name`. Object versioning is not supported.
    //    See [Google Cloud Storage Request
    //    URIs](https://cloud.google.com/storage/docs/reference-uris) for more
    //    info.
    string uri = 1 [(google.api.field_behavior) = OPTIONAL];

    // Optional. Inline document content, represented as a stream of bytes.
    // Note: As with all `bytes` fields, protobuffers use a pure binary
    // representation, whereas JSON representations use base64.
    bytes content = 2 [(google.api.field_behavior) = OPTIONAL];
  }

  // An IANA published MIME type (also referred to as media type). For more
  // information, see
  // https://www.iana.org/assignments/media-types/media-types.xhtml.
  string mime_type = 3;

  // Optional. UTF-8 encoded text in reading order from the document.
  string text = 4 [(google.api.field_behavior) = OPTIONAL];

  // Placeholder.  Styles for the [Document.text][google.cloud.documentai.v1.Document.text].
  repeated Style text_styles = 5;

  // Visual page layout for the [Document][google.cloud.documentai.v1.Document].
  repeated Page pages = 6;

  // A list of entities detected on [Document.text][google.cloud.documentai.v1.Document.text]. For document shards,
  // entities in this list may cross shard boundaries.
  repeated Entity entities = 7;

  // Placeholder.  Relationship among [Document.entities][google.cloud.documentai.v1.Document.entities].
  repeated EntityRelation entity_relations = 8;

  // Placeholder.  A list of text corrections made to [Document.text][google.cloud.documentai.v1.Document.text].  This
  // is usually used for annotating corrections to OCR mistakes.  Text changes
  // for a given revision may not overlap with each other.
  repeated TextChange text_changes = 14;

  // Information about the sharding if this document is sharded part of a larger
  // document. If the document is not sharded, this message is not specified.
  ShardInfo shard_info = 9;

  // Any error that occurred while processing this document.
  google.rpc.Status error = 10;

  // Placeholder. Revision history of this document.
  repeated Revision revisions = 13;
}