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// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/ui/webui/tab_strip/thumbnail_tracker.h"
#include <memory>
#include <utility>
#include "base/memory/raw_ptr.h"
#include "base/scoped_observation.h"
#include "chrome/browser/ui/thumbnails/thumbnail_tab_helper.h"
#include "content/public/browser/web_contents_observer.h"
// Handles requests for a given tab's thumbnail and watches for thumbnail
// updates for the lifetime of the tab.
class ThumbnailTracker::ContentsData : public content::WebContentsObserver {
public:
ContentsData(ThumbnailTracker* parent, content::WebContents* contents)
: content::WebContentsObserver(contents), parent_(parent) {
thumbnail_ = parent_->thumbnail_getter_.Run(contents);
if (!thumbnail_) {
return;
}
subscription_ = thumbnail_->Subscribe();
subscription_->SetCompressedImageCallback(base::BindRepeating(
&ContentsData::ThumbnailImageCallback, base::Unretained(this)));
}
ContentsData(const ContentsData&) = delete;
ContentsData& operator=(const ContentsData&) = delete;
void RequestThumbnail() {
if (thumbnail_) {
thumbnail_->RequestCompressedThumbnailData();
}
}
// content::WebContents:
void WebContentsDestroyed() override {
// We must un-observe each ThumbnailImage when the WebContents it came from
// closes.
if (thumbnail_) {
subscription_.reset();
thumbnail_.reset();
}
// Destroy ourself. After this call, |this| doesn't exist!
parent_->ContentsClosed(web_contents());
}
private:
void ThumbnailImageCallback(CompressedThumbnailData image) {
parent_->ThumbnailUpdated(web_contents(), image);
}
raw_ptr<ThumbnailTracker> parent_;
scoped_refptr<ThumbnailImage> thumbnail_;
std::unique_ptr<ThumbnailImage::Subscription> subscription_;
};
ThumbnailTracker::ThumbnailTracker(ThumbnailUpdatedCallback callback)
: ThumbnailTracker(std::move(callback),
base::BindRepeating(GetThumbnailFromTabHelper)) {}
ThumbnailTracker::ThumbnailTracker(ThumbnailUpdatedCallback callback,
GetThumbnailCallback thumbnail_getter)
: thumbnail_getter_(std::move(thumbnail_getter)),
callback_(std::move(callback)) {}
ThumbnailTracker::~ThumbnailTracker() = default;
void ThumbnailTracker::AddTab(content::WebContents* contents) {
auto data_it = contents_data_.find(contents);
if (data_it == contents_data_.end()) {
data_it = contents_data_.emplace_hint(
data_it, contents, std::make_unique<ContentsData>(this, contents));
}
data_it->second->RequestThumbnail();
}
void ThumbnailTracker::RemoveTab(content::WebContents* contents) {
contents_data_.erase(contents);
}
void ThumbnailTracker::ThumbnailUpdated(content::WebContents* contents,
CompressedThumbnailData image) {
callback_.Run(contents, image);
}
void ThumbnailTracker::ContentsClosed(content::WebContents* contents) {
contents_data_.erase(contents);
}
// static
scoped_refptr<ThumbnailImage> ThumbnailTracker::GetThumbnailFromTabHelper(
content::WebContents* contents) {
ThumbnailTabHelper* thumbnail_helper =
ThumbnailTabHelper::FromWebContents(contents);
// Gracefully handle when ThumbnailTabHelper isn't available.
if (thumbnail_helper) {
auto thumbnail = thumbnail_helper->thumbnail();
DCHECK(thumbnail);
return thumbnail;
} else {
DVLOG(1) << "ThumbnailTabHelper doesn't exist for tab";
return nullptr;
}
}
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