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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.
#ifndef CHROME_BROWSER_UI_ASH_THUMBNAIL_LOADER_THUMBNAIL_LOADER_H_
#define CHROME_BROWSER_UI_ASH_THUMBNAIL_LOADER_THUMBNAIL_LOADER_H_
#include <map>
#include <memory>
#include <string>
#include "base/files/file.h"
#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/unguessable_token.h"
#include "ui/gfx/geometry/size.h"
class Profile;
class SkBitmap;
namespace base {
class FilePath;
}
namespace ash {
// Loader for file-backed thumbnails. It opens a native connection to the image
// loader extension (also used to generate thumbnails for the file manager), and
// sends it an image request for a file path. It decodes data returned by the
// extension into a bitmap.
class ThumbnailLoader {
public:
explicit ThumbnailLoader(Profile* profile);
ThumbnailLoader(const ThumbnailLoader&) = delete;
ThumbnailLoader& operator=(const ThumbnailLoader&) = delete;
virtual ~ThumbnailLoader();
// Thumbnail request data that will be forwarded to the image loader.
struct ThumbnailRequest {
ThumbnailRequest(const base::FilePath& file_path, const gfx::Size& size);
~ThumbnailRequest();
// The absolute file path.
const base::FilePath file_path;
// The desired bitmap size.
const gfx::Size size;
};
// Returns a weak pointer to this instance.
base::WeakPtr<ThumbnailLoader> GetWeakPtr();
using ImageCallback =
base::OnceCallback<void(const SkBitmap* bitmap, base::File::Error error)>;
// Starts a request for a thumbnail. `callback` called with the generated
// bitmap. On error, the bitmap will be null.
virtual void Load(const ThumbnailRequest& request, ImageCallback callback);
private:
class ThumbnailDecoder;
// Starts thumbnail request after the file metadata has been retrieved. The
// metadata is used to verify that the path exists, points to a file, and to
// get the file's last modification time.
void LoadForFileWithMetadata(const ThumbnailRequest& request,
ImageCallback callback,
base::File::Error result,
const base::File::Info& file_info);
// Callback to the image loader request.
// `request_id` identifies the thumbnail request.
// `requested_size` - size of the thumbnail that was requested.
// `data` - image data returned by the image loader. Expected to be in a data
// URL form. It will attempt to decode the received data.
void OnThumbnailLoaded(const base::UnguessableToken& request_id,
const gfx::Size& requested_size,
const std::string& data);
// Finalizes the thumbnail request identified by `request_id`. It invokes the
// request callback with `bitmap`. If `bitmap` size is larger than the
// originally `requested_size`, the bitmap will be cropped.
void RespondToRequest(const base::UnguessableToken& request_id,
const gfx::Size& requested_size,
const SkBitmap* bitmap,
base::File::Error error);
const raw_ptr<Profile, DanglingUntriaged> profile_;
// Maps pending thumbnail requests to their registered callbacks.
std::map<base::UnguessableToken, ImageCallback> requests_;
// Maps pending thumbnail requests to image decoders used to transform data
// received from the image loder into a bitmap.
std::map<base::UnguessableToken, std::unique_ptr<ThumbnailDecoder>>
thumbnail_decoders_;
base::WeakPtrFactory<ThumbnailLoader> weak_factory_{this};
};
} // namespace ash
#endif // CHROME_BROWSER_UI_ASH_THUMBNAIL_LOADER_THUMBNAIL_LOADER_H_
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