1// Copyright 2013 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CHROME_BROWSER_EXTENSIONS_API_BRAILLE_DISPLAY_PRIVATE_BRLAPI_CONNECTION_H_
6#define CHROME_BROWSER_EXTENSIONS_API_BRAILLE_DISPLAY_PRIVATE_BRLAPI_CONNECTION_H_
7
8#include "base/basictypes.h"
9#include "base/callback_forward.h"
10#include "base/memory/scoped_ptr.h"
11#include "library_loaders/libbrlapi.h"
12
13namespace extensions {
14namespace api {
15namespace braille_display_private {
16
17// A connection to the brlapi server.  See brlapi.h for more information
18// about the semantics of the methods in this class.
19class BrlapiConnection {
20 public:
21  typedef base::Closure OnDataReadyCallback;
22
23  enum ConnectResult {
24    CONNECT_ERROR_RETRY,
25    CONNECT_ERROR_NO_RETRY,
26    CONNECT_SUCCESS,
27  };
28
29  static scoped_ptr<BrlapiConnection> Create(LibBrlapiLoader* loader);
30
31  virtual ~BrlapiConnection();
32
33  virtual ConnectResult Connect(const OnDataReadyCallback& onDataReady) = 0;
34
35  virtual void Disconnect() = 0;
36
37  virtual bool Connected() = 0;
38
39  // Gets the last brlapi error on this thread.
40  // This works ismilar to errno in C.  There's one thread-local error
41  // value, meaning that this method should be called after any
42  // other method of this class that can return an error without calling
43  // another method in between.  This class is not thread safe.
44  virtual brlapi_error_t* BrlapiError() = 0;
45
46  // Gets a description of the last brlapi error for this thread, useful
47  // for logging.
48  virtual std::string BrlapiStrError() = 0;
49
50  // Gets the total size of the display, which may be 0 if no display is
51  // present, returning true on success.  Note that this is cached in the
52  // brlapi client so it is cheap.
53  virtual bool GetDisplaySize(size_t* size) = 0;
54
55  // Sends the specified cells to the display.  The array size must
56  // be equal to what GetDisplaySize() last returned for this connection.
57  virtual bool WriteDots(const unsigned char* cells) = 0;
58
59  // Reads the next keyboard command, returning true on success.
60  // Returns < 0 on error, 0 if no more keys are pending and > 0
61  // on success, in which case keyCode will be set to the key command
62  // value.
63  virtual int ReadKey(brlapi_keyCode_t* keyCode) = 0;
64
65 protected:
66  BrlapiConnection();
67  DISALLOW_COPY_AND_ASSIGN(BrlapiConnection);
68};
69
70}  // namespace braille_display_private
71}  // namespace api
72}  // namespace extensions
73
74#endif  // CHROME_BROWSER_EXTENSIONS_API_BRAILLE_DISPLAY_PRIVATE_BRLAPI_CONNECTION_H_
75