Support standard keyboard keys emulated by the braille drivers.

chrome/browser/extensions/api/braille_display_private/brlapi_keycode_map.cc

+// Copyright 2014 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.
+
+#include "chrome/browser/extensions/api/braille_display_private/brlapi_keycode_map.h"
+
+#include "base/strings/stringprintf.h"
+#include "base/strings/utf_string_conversion_utils.h"
+
+namespace extensions {
+namespace api {
+namespace braille_display_private {
+
+namespace {
+// Bitmask for all braille dots in a key command argument, which coincides
+// with the representation in the braille_dots member of the KeyEvent
+// class.
+const int kAllDots = BRLAPI_DOT1 | BRLAPI_DOT2 | BRLAPI_DOT3 | BRLAPI_DOT4 |
+                     BRLAPI_DOT5 | BRLAPI_DOT6 | BRLAPI_DOT7 | BRLAPI_DOT8;
+
+// Maximum Laitn 1 character keyboard symbol.

[David Tseng, 2014/05/27 21:29:31]

Latin

+const brlapi_keyCode_t kMaxLatin1KeySym = 0xff;
+
+// Range of function keys that we support.
+// See ui/events/keycodes/dom4/keycode_converter_data.h for the list of all
+// key codes.
+const brlapi_keyCode_t kMinFunctionKey = BRLAPI_KEY_SYM_FUNCTION;
+const brlapi_keyCode_t kMaxFunctionKey = BRLAPI_KEY_SYM_FUNCTION + 23;
+
+// Maps the keyboard modifier flags to their corresponding flags in a
+// |KeyEvent|.
+void MapModifierFlags(brlapi_keyCode_t code, KeyEvent* event) {
+  if (code & BRLAPI_KEY_FLG_CONTROL)
+    event->ctrl_key.reset(new bool(true));
+  if (code & BRLAPI_KEY_FLG_META)
+    event->alt_key.reset(new bool(true));
+  if (code & BRLAPI_KEY_FLG_SHIFT)
+    event->shift_key.reset(new bool(true));

[David Tseng, 2014/05/27 21:29:31]

Do we get any other modifiers?

+}
+
+// Maps a brlapi keysym, which is similar to an X keysym into the
+// provided event.
+void MapKeySym(brlapi_keyCode_t code, KeyEvent* event) {
+  brlapi_keyCode_t key_sym = code & BRLAPI_KEY_CODE_MASK;
+  if (key_sym < kMaxLatin1KeySym ||
+      (key_sym & BRLAPI_KEY_SYM_UNICODE) != 0) {
+    uint32 code_point = key_sym & ~BRLAPI_KEY_SYM_UNICODE;
+    if (!base::IsValidCharacter(code_point))
+      return;
+    event->standard_key_char.reset(new std::string);
+    base::WriteUnicodeCharacter(code_point, event->standard_key_char.get());
+  } else if (key_sym >= kMinFunctionKey && key_sym <= kMaxFunctionKey) {
+    // Function keys are 0-based here, so we need to add one to get e.g.
+    // 'F1' for the first key.
+    int function_key_number = key_sym - kMinFunctionKey + 1;
+    event->standard_key_code.reset(
+        new std::string(base::StringPrintf("F%d", function_key_number)));
+  } else {
+    // Explicitly map the keys that brlapi provides.
+    const char* code_string;
+    switch (key_sym) {
+      case BRLAPI_KEY_SYM_BACKSPACE:
+        code_string = "Backspace";

[David Tseng, 2014/05/27 21:29:31]

Where do these strings come from?

+        break;
+      case BRLAPI_KEY_SYM_TAB:
+        code_string = "Tab";
+        break;
+      case BRLAPI_KEY_SYM_LINEFEED:
+        code_string = "Enter";
+        break;
+      case BRLAPI_KEY_SYM_ESCAPE:
+        code_string = "Escape";
+        break;
+      case BRLAPI_KEY_SYM_HOME:
+        code_string = "Home";
+        break;
+      case BRLAPI_KEY_SYM_LEFT:
+        code_string = "ArrowLeft";
+        break;
+      case BRLAPI_KEY_SYM_UP:
+        code_string = "ArrowUp";
+        break;
+      case BRLAPI_KEY_SYM_RIGHT:
+        code_string = "ArrowRight";
+        break;
+      case BRLAPI_KEY_SYM_DOWN:
+        code_string = "ArrowDown";
+        break;
+      case BRLAPI_KEY_SYM_PAGE_UP:
+        code_string = "PageUp";
+        break;
+      case BRLAPI_KEY_SYM_PAGE_DOWN:
+        code_string = "PageDown";
+        break;
+      case BRLAPI_KEY_SYM_END:
+        code_string = "End";
+        break;
+      case BRLAPI_KEY_SYM_INSERT:
+        code_string = "Insert";
+        break;
+      case BRLAPI_KEY_SYM_DELETE:
+        code_string = "Delete";
+        break;
+      default:
+        return;

[David Tseng, 2014/05/27 21:29:31]

DCHECK?

+    }
+    event->standard_key_code.reset(new std::string(code_string));
+  }
+  MapModifierFlags(code, event);
+  event->command = KEY_COMMAND_STANDARD_KEY;
+}
+
+void MapCommand(brlapi_keyCode_t code, KeyEvent* event) {
+  brlapi_keyCode_t argument = code & BRLAPI_KEY_CMD_ARG_MASK;
+  switch (code & BRLAPI_KEY_CODE_MASK) {
+    case BRLAPI_KEY_CMD_LNUP:
+      event->command = KEY_COMMAND_LINE_UP;
+      break;
+    case BRLAPI_KEY_CMD_LNDN:
+      event->command = KEY_COMMAND_LINE_DOWN;
+      break;
+    case BRLAPI_KEY_CMD_FWINLT:
+      event->command = KEY_COMMAND_PAN_LEFT;
+      break;
+    case BRLAPI_KEY_CMD_FWINRT:
+      event->command = KEY_COMMAND_PAN_RIGHT;
+      break;
+    case BRLAPI_KEY_CMD_TOP:
+      event->command = KEY_COMMAND_TOP;
+      break;
+    case BRLAPI_KEY_CMD_BOT:
+      event->command = KEY_COMMAND_BOTTOM;
+      break;
+    default:
+      switch (code & BRLAPI_KEY_CMD_BLK_MASK) {
+        case BRLAPI_KEY_CMD_ROUTE:
+          event->command = KEY_COMMAND_ROUTING;
+          event->display_position.reset(new int(argument));
+          break;
+        case BRLAPI_KEY_CMD_PASSDOTS:
+          event->command = KEY_COMMAND_DOTS;
+          event->braille_dots.reset(new int(argument & kAllDots));

[David Tseng, 2014/05/27 21:29:31]

When would |argument| have bits not in kAllDots set? Is that an error?

+          MapModifierFlags(code, event);
+          break;
+      }
+  }
+}
+
+}  // namespace
+
+scoped_ptr<KeyEvent> BrlapiKeyCodeToEvent(brlapi_keyCode_t code) {
+  scoped_ptr<KeyEvent> result(new KeyEvent);
+  result->command = KEY_COMMAND_NONE;
+  switch (code & BRLAPI_KEY_TYPE_MASK) {
+    case BRLAPI_KEY_TYPE_SYM:
+      MapKeySym(code, result.get());
+      break;
+    case BRLAPI_KEY_TYPE_CMD:
+      MapCommand(code, result.get());
+      break;
+  }
+  if (result->command == KEY_COMMAND_NONE)
+    result.reset();
+  return result.Pass();
+}
+
+}  // namespace braille_display_private
+}  // namespace api
+}  // namespace extensions