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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/feed/core/v2/tasks/prefetch_images_task.h"
#include <utility>
#include "base/functional/callback.h"
#include "base/functional/callback_helpers.h"
#include "base/logging.h"
#include "components/feed/core/proto/v2/wire/stream_structure.pb.h"
#include "components/feed/core/v2/config.h"
#include "components/feed/core/v2/feed_store.h"
#include "components/feed/core/v2/feed_stream.h"
#include "components/feed/core/v2/public/feed_api.h"
#include "components/feed/core/v2/stream_model.h"
#include "components/feed/core/v2/tasks/load_stream_from_store_task.h"
namespace feed {
namespace {
// Converts a URL string into a GURL. If the string is not a valid URL, returns
// an empty GURL. Since GURL::spec() asserts on invalid URLs, this is necessary
// to scrub the incoming data from the wire.
GURL SpecToGURL(const std::string& url_string) {
GURL url(url_string);
if (!url.is_valid())
url = GURL();
return url;
}
} // namespace
PrefetchImagesTask::PrefetchImagesTask(FeedStream* stream) : stream_(*stream) {
max_images_per_refresh_ =
GetFeedConfig().max_prefetch_image_requests_per_refresh;
}
PrefetchImagesTask::~PrefetchImagesTask() = default;
void PrefetchImagesTask::Run() {
if (stream_->ClearAllInProgress()) {
// Abort if ClearAll is in progress.
TaskComplete();
return;
}
StreamType for_you_stream = StreamType(StreamKind::kForYou);
if (stream_->GetModel(for_you_stream)) {
PrefetchImagesFromModel(*stream_->GetModel(for_you_stream));
return;
}
// Web feed subscriber is set to true so we don't use the less restrictive
// staleness number for when there are no subscriptions.
load_from_store_task_ = std::make_unique<LoadStreamFromStoreTask>(
LoadStreamFromStoreTask::LoadType::kFullLoad, &*stream_, for_you_stream,
&stream_->GetStore(),
/*missed_last_refresh=*/false,
/*is_web_feed_subscriber=*/true,
base::BindOnce(&PrefetchImagesTask::LoadStreamComplete,
base::Unretained(this)));
load_from_store_task_->Execute(base::DoNothing());
}
void PrefetchImagesTask::LoadStreamComplete(
LoadStreamFromStoreTask::Result result) {
if (!result.update_request) {
TaskComplete();
return;
}
// It is a bit dangerous to retain the model loaded here. The normal
// LoadStreamTask flow has various considerations for metrics and signalling
// surfaces to update. For this reason, we're not going to retain the loaded
// model for use outside of this task.
StreamModel::Context model_context;
StreamModel model(&model_context, LoggingParameters{});
model.Update(std::move(result.update_request));
PrefetchImagesFromModel(model);
}
void PrefetchImagesTask::PrefetchImagesFromModel(const StreamModel& model) {
for (ContentRevision rev : model.GetContentList()) {
const feedstore::Content* content = model.FindContent(rev);
if (!content)
continue;
for (const feedwire::PrefetchMetadata& metadata :
content->prefetch_metadata()) {
MaybePrefetchImage(SpecToGURL(metadata.image_url()));
MaybePrefetchImage(SpecToGURL(metadata.favicon_url()));
for (const std::string& url : metadata.additional_image_urls()) {
MaybePrefetchImage(SpecToGURL(url));
}
}
}
TaskComplete();
}
void PrefetchImagesTask::MaybePrefetchImage(const GURL& gurl) {
// If we've already fetched this url, or we've hit the max number of fetches,
// then don't send a fetch request.
if (!gurl.is_valid() ||
(previously_fetched_.find(gurl.spec()) != previously_fetched_.end()) ||
previously_fetched_.size() >= max_images_per_refresh_)
return;
previously_fetched_.insert(gurl.spec());
stream_->PrefetchImage(gurl);
}
} // namespace feed
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