blob: 202b8a4badf5e0eb9b542c4ec033850c062a7561 [file] [log] [blame]
// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/single_thread_task_runner.h"
namespace offline_pages {
// Takes various signals and produces StartSnapshot calls following a specific
// policy.
// Main invariants:
// - Some signals prevent more snapshots to be taken.
// OnLoad is currently such signal.
// - Once Reset() is called on the BackgroundSnapshotController, the delayed
// tasks are reset so no StartSnapshot calls is made 'cross-session'.
class BackgroundSnapshotController {
enum class State {
READY, // Listening to input, will start snapshot when needed.
SNAPSHOT_PENDING, // Snapshot is in progress, don't start another.
STOPPED, // Terminal state, no snapshots until reset.
// The expected quality of a page based on its current loading progress.
enum class PageQuality {
// Not loaded enough to reach a minimum level of quality. Snapshots taken at
// this point are expected to be useless.
POOR = 0,
// A minimal level of quality has been attained but the page is still
// loading so its quality is continuously increasing. One or more snapshots
// could be taken at this stage as later ones are expected to have higher
// quality.
// The page is loaded enough and has attained its peak expected quality.
// Snapshots taken at this point are not expected to increase in quality
// after the first one.
// Client of the BackgroundSnapshotController.
class Client {
// Invoked at a good moment to start a snapshot.
virtual void StartSnapshot() = 0;
// Invoked when the page is sufficiently loaded for running
// renovations. The client should call the RenovationsCompleted()
// when they finish.
virtual void RunRenovations() = 0;
virtual ~Client() {}
const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
BackgroundSnapshotController::Client* client,
bool renovations_enabled);
virtual ~BackgroundSnapshotController();
// Resets the 'session', returning controller to initial state.
void Reset();
// Stops current session, no more Client::StartSnapshot calls will be
// invoked from the BackgroundSnapshotController until current session is
// Reset(). Called by Client, for example when it encounters an error loading
// the page.
void Stop();
// The Client calls this when renovations have completed.
void RenovationsCompleted();
// Invoked from WebContentObserver::DocumentOnLoadCompletedInMainFrame
void DocumentOnLoadCompletedInMainFrame();
int64_t GetDelayAfterDocumentOnLoadCompletedForTest();
int64_t GetDelayAfterRenovationsCompletedForTest();
void MaybeStartSnapshot();
void MaybeStartSnapshotThenStop();
scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
// Client owns this class.
BackgroundSnapshotController::Client* client_;
BackgroundSnapshotController::State state_;
int64_t delay_after_document_on_load_completed_ms_;
int64_t delay_after_renovations_completed_ms_;
bool renovations_enabled_;
base::WeakPtrFactory<BackgroundSnapshotController> weak_ptr_factory_;
} // namespace offline_pages