annotator_impl.h | Explore in Territory

// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_BROWSING_TOPICS_ANNOTATOR_IMPL_H_
#define COMPONENTS_BROWSING_TOPICS_ANNOTATOR_IMPL_H_

#include <optional>
#include <string>
#include <unordered_map>
#include <vector>

#include "base/callback_list.h"
#include "base/files/file_path.h"
#include "base/functional/callback.h"
#include "base/memory/weak_ptr.h"
#include "base/sequence_checker.h"
#include "base/task/sequenced_task_runner.h"
#include "components/browsing_topics/annotator.h"
#include "components/optimization_guide/core/bert_model_handler.h"

namespace optimization_guide {
class OptimizationGuideModelProvider;
}

namespace browsing_topics {

// An implementation of the |Annotator| base class. This Annotator supports
// concurrent batch annotations and manages the lifetimes of all underlying
// components. This class must only be owned and called on the UI thread.
//
// |BatchAnnotate| is the main entry point for callers. The callback given to
// |BatchAnnotate| is forwarded through many subsequent PostTasks until all
// annotations are ready to be returned to the caller.
//
// Life of an Annotation:
// 1. |BatchAnnotate| checks if the override list needs to be loaded. If so, it
// is done on a background thread. After that check and possibly loading the
// list in |OnOverrideListLoadAttemptDone|, |StartBatchAnnotate| is called.
// 2. |StartBatchAnnotate| shares ownership of the |BatchAnnotationCallback|
// among a series of callbacks (using |base::BarrierClosure|), one for each
// input. Ownership of the inputs is moved to the heap where all individual
// model executions can reference their input and set their output.
// 3. |AnnotateSingleInput| runs a single annotation, first checking the
// override list if available. If the input is not covered in the override list,
// the ML model is run on a background thread.
// 4. |PostprocessCategoriesToBatchAnnotationResult| is called to post-process
// the output of the ML model.
// 5. |OnBatchComplete| is called by the barrier closure which passes the
// annotations back to the caller and unloads the model if no other batches are
// in progress.
class AnnotatorImpl : public Annotator,
                      public optimization_guide::BertModelHandler { … };

}  // namespace browsing_topics

#endif  // COMPONENTS_BROWSING_TOPICS_ANNOTATOR_IMPL_H_
chromium/components/browsing_topics/annotator_impl.h
