components/optimization_guide/content/mojom/page_text_service.mojom

// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

module optimization_guide.mojom;

import "mojo/public/mojom/base/string16.mojom";

// The events at which taking a text dump are supported.
enum TextDumpEvent {
  // The first layout on the page. Equal to
  // blink::WebMeaningfulLayout::kFinishedParsing. Note that the text dumped at
  // this event is not deterministic due to races in the renderer. In particular
  // some text that may have been populated after the "real" first layout event
  // may also be captured.
  kFirstLayout,

  // The page is finished loading. Equal to
  // blink::WebMeaningfulLayout::kFinishedLoading.
  kFinishedLoad,
};

// A request for a page text dump.
struct PageTextDumpRequest {
  // The maximum size of the requested text dump, in bytes. Note that the actual
  // dump size may be less than this value on pages with little text.
  uint32 max_size;

  // The event at which the text dump should be taken.
  TextDumpEvent event;
};

// Implemented by the browser process to consume the text dumped from the
// webpage. The page text is sent in chunks since the total length of the
// webpage's text may exceed the mojo pipe size. Chunks are sent in order until
// OnChunksEnd is called, after which no further calls will be made on the
// instance.
interface PageTextConsumer {
  // Called for each chunk of page text.
  // Security note: |chunk| should be treated as untrusted data.
  OnTextDumpChunk(mojo_base.mojom.String16 chunk);

  // Called when no more chunks will be sent.
  OnChunksEnd();
};


// Implemented by the renderer process to provide a way to request dumps of the
// text from the webpage at specific events.
interface PageTextService {
  // Requests a page text dump with the given request parameters. The dumped
  // page text will be sent in chunks to consumer.
  RequestPageTextDump(PageTextDumpRequest request,
                      pending_remote<PageTextConsumer> consumer);
};