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// Copyright 2013 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.
#ifndef CHROME_BROWSER_EXTENSIONS_API_BRAILLE_DISPLAY_PRIVATE_BRLAPI_CONNECTION_H_
#define CHROME_BROWSER_EXTENSIONS_API_BRAILLE_DISPLAY_PRIVATE_BRLAPI_CONNECTION_H_
#include <stddef.h>
#include <memory>
#include <vector>
#include "base/callback_forward.h"
#include "base/macros.h"
#include "library_loaders/libbrlapi.h"
namespace extensions {
namespace api {
namespace braille_display_private {
// A connection to the brlapi server. See brlapi.h for more information
// about the semantics of the methods in this class.
class BrlapiConnection {
public:
typedef base::Closure OnDataReadyCallback;
enum ConnectResult {
CONNECT_ERROR_RETRY,
CONNECT_ERROR_NO_RETRY,
CONNECT_SUCCESS,
};
static std::unique_ptr<BrlapiConnection> Create(LibBrlapiLoader* loader);
virtual ~BrlapiConnection();
virtual ConnectResult Connect(const OnDataReadyCallback& onDataReady) = 0;
virtual void Disconnect() = 0;
virtual bool Connected() = 0;
// Gets the last brlapi error on this thread.
// This works similar to errno in C. There's one thread-local error
// value, meaning that this method should be called after any
// other method of this class that can return an error without calling
// another method in between. This class is not thread safe.
virtual brlapi_error_t* BrlapiError() = 0;
// Gets a description of the last brlapi error for this thread, useful
// for logging.
virtual std::string BrlapiStrError() = 0;
// Gets the row and column size of the display. Row x columns might be 0
// if no display is present, returning true on success. Note that this is
// cached in the brlapi client so it is cheap.
virtual bool GetDisplaySize(unsigned int* columns, unsigned int* rows) = 0;
// Sends the specified cells to the display. The array size must
// be equal to what GetDisplaySize() last returned for this connection,
// that is, cells must have a size of rows x columns.
virtual bool WriteDots(const std::vector<unsigned char>& cells) = 0;
// Reads the next keyboard command, returning true on success.
// Returns < 0 on error, 0 if no more keys are pending and > 0
// on success, in which case keyCode will be set to the key command
// value.
virtual int ReadKey(brlapi_keyCode_t* keyCode) = 0;
protected:
BrlapiConnection();
DISALLOW_COPY_AND_ASSIGN(BrlapiConnection);
};
} // namespace braille_display_private
} // namespace api
} // namespace extensions
#endif // CHROME_BROWSER_EXTENSIONS_API_BRAILLE_DISPLAY_PRIVATE_BRLAPI_CONNECTION_H_
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