Make InputMethodEngine to inherit from new added class InputMethodEngineBase.

chrome/browser/input_method/input_method_engine_base.cc

+// Copyright 2016 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/input_method/input_method_engine_base.h"
+
+#undef FocusIn
+#undef FocusOut
+#undef RootWindow
+#include <algorithm>
+#include <map>
+
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/metrics/histogram.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
+#include "base/strings/utf_string_conversions.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "ui/aura/window.h"
+#include "ui/aura/window_tree_host.h"
+#include "ui/base/ime/composition_text.h"
+#include "ui/base/ime/ime_bridge.h"
+#include "ui/base/ime/text_input_flags.h"
+#include "ui/events/event.h"
+#include "ui/events/event_processor.h"
+#include "ui/events/event_utils.h"
+#include "ui/events/keycodes/dom/dom_code.h"
+#include "ui/keyboard/keyboard_controller.h"
+#include "ui/keyboard/keyboard_util.h"
+
+#if defined(OS_CHROMEOS)
+#include "ui/base/ime/chromeos/ime_keymap.h"
+#elif defined(OS_WIN)
+#include "ui/events/keycodes/dom/keycode_converter.h"
+#include "ui/events/keycodes/keyboard_codes_win.h"
+#elif defined(OS_LINUX)
+#include "ui/events/keycodes/dom/keycode_converter.h"
+#include "ui/events/keycodes/keyboard_codes_posix.h"
+#endif
+
+namespace input_method {
+
+namespace {
+
+const char kErrorNotActive[] = "IME is not active";
+const char kErrorWrongContext[] = "Context is not active";
+
+// Notifies InputContextHandler that the composition is changed.
+void UpdateComposition(const ui::CompositionText& composition_text,
+                       uint32_t cursor_pos,
+                       bool is_visible) {
+  ui::IMEInputContextHandlerInterface* input_context =
+      ui::IMEBridge::Get()->GetInputContextHandler();
+  if (input_context)
+    input_context->UpdateCompositionText(composition_text, cursor_pos,
+                                         is_visible);
+}
+
+// Returns the length of characters of a UTF-8 string with unknown string
+// length. Cannot apply faster algorithm to count characters in an utf-8
+// string without knowing the string length,  so just does a full scan.
+size_t GetUtf8StringLength(const char* s) {
+  size_t ret = 0;
+  while (*s) {
+    if ((*s & 0xC0) != 0x80)
+      ret++;
+    ++s;
+  }
+  return ret;
+}
+
+#if defined(OS_CHROMEOS)
+std::string GetKeyFromEvent(const ui::KeyEvent& event) {
+  const std::string code = event.GetCodeString();
+  if (base::StartsWith(code, "Control", base::CompareCase::SENSITIVE))
+    return "Ctrl";
+  if (base::StartsWith(code, "Shift", base::CompareCase::SENSITIVE))
+    return "Shift";
+  if (base::StartsWith(code, "Alt", base::CompareCase::SENSITIVE))
+    return "Alt";
+  if (base::StartsWith(code, "Arrow", base::CompareCase::SENSITIVE))
+    return code.substr(5);
+  if (code == "Escape")
+    return "Esc";
+  if (code == "Backspace" || code == "Tab" || code == "Enter" ||
+      code == "CapsLock" || code == "Power")
+    return code;
+  // Cases for media keys.
+  switch (event.key_code()) {
+    case ui::VKEY_BROWSER_BACK:
+    case ui::VKEY_F1:
+      return "HistoryBack";
+    case ui::VKEY_BROWSER_FORWARD:
+    case ui::VKEY_F2:
+      return "HistoryForward";
+    case ui::VKEY_BROWSER_REFRESH:
+    case ui::VKEY_F3:
+      return "BrowserRefresh";
+    case ui::VKEY_MEDIA_LAUNCH_APP2:
+    case ui::VKEY_F4:
+      return "ChromeOSFullscreen";
+    case ui::VKEY_MEDIA_LAUNCH_APP1:
+    case ui::VKEY_F5:
+      return "ChromeOSSwitchWindow";
+    case ui::VKEY_BRIGHTNESS_DOWN:
+    case ui::VKEY_F6:
+      return "BrightnessDown";
+    case ui::VKEY_BRIGHTNESS_UP:
+    case ui::VKEY_F7:
+      return "BrightnessUp";
+    case ui::VKEY_VOLUME_MUTE:
+    case ui::VKEY_F8:
+      return "AudioVolumeMute";
+    case ui::VKEY_VOLUME_DOWN:
+    case ui::VKEY_F9:
+      return "AudioVolumeDown";
+    case ui::VKEY_VOLUME_UP:
+    case ui::VKEY_F10:
+      return "AudioVolumeUp";
+    default:
+      break;
+  }
+  uint16_t ch = 0;
+  // Ctrl+? cases, gets key value for Ctrl is not down.
+  if (event.flags() & ui::EF_CONTROL_DOWN) {
+    ui::KeyEvent event_no_ctrl(event.type(), event.key_code(),
+                               event.flags() ^ ui::EF_CONTROL_DOWN);
+    ch = event_no_ctrl.GetCharacter();
+  } else {
+    ch = event.GetCharacter();
+  }
+  return base::UTF16ToUTF8(base::string16(1, ch));
+}
+#endif  // defined(OS_CHROMEOS)
+
+void GetExtensionKeyboardEventFromKeyEvent(
+    const ui::KeyEvent& event,
+    InputMethodEngineBase::KeyboardEvent* ext_event) {
+  DCHECK(event.type() == ui::ET_KEY_RELEASED ||
+         event.type() == ui::ET_KEY_PRESSED);
+  DCHECK(ext_event);
+  ext_event->type = (event.type() == ui::ET_KEY_RELEASED) ? "keyup" : "keydown";
+
+  if (event.code() == ui::DomCode::NONE) {
+// TODO(azurewei): Use KeycodeConverter::DomCodeToCodeString on all platforms
+#if defined(OS_CHROMEOS)
+    ext_event->code = ui::KeyboardCodeToDomKeycode(event.key_code());
+#else
+    ext_event->code =
+        std::string(ui::KeycodeConverter::DomCodeToCodeString(event.code()));
+#endif
+  } else {
+    ext_event->code = event.GetCodeString();
+  }
+  ext_event->key_code = static_cast<int>(event.key_code());
+  ext_event->alt_key = event.IsAltDown();
+  ext_event->ctrl_key = event.IsControlDown();
+  ext_event->shift_key = event.IsShiftDown();
+  ext_event->caps_lock = event.IsCapsLockDown();
+#if defined(OS_CHROMEOS)
+  ext_event->key = GetKeyFromEvent(event);
+#else
+  ext_event->key = ui::KeycodeConverter::DomKeyToKeyString(event.GetDomKey());
+#endif  // defined(OS_CHROMEOS)
+}
+
+}  // namespace
+
+InputMethodEngineBase::InputMethodEngineBase()
+    : current_input_type_(ui::TEXT_INPUT_TYPE_NONE),
+      context_id_(0),
+      next_context_id_(1),
+      composition_text_(new ui::CompositionText()),
+      composition_cursor_(0),
+      sent_key_event_(NULL),
+      profile_(NULL) {}
+
+InputMethodEngineBase::~InputMethodEngineBase() {}
+
+void InputMethodEngineBase::Initialize(
+    scoped_ptr<ui::IMEEngineObserver> observer,
+    const char* extension_id,
+    Profile* profile) {
+  DCHECK(observer) << "Observer must not be null.";
+
+  // TODO(komatsu): It is probably better to set observer out of Initialize.
+  observer_ = std::move(observer);
+  extension_id_ = extension_id;
+  profile_ = profile;
+}
+
+const std::string& InputMethodEngineBase::GetActiveComponentId() const {
+  return active_component_id_;
+}
+
+bool InputMethodEngineBase::SetComposition(
+    int context_id,
+    const char* text,
+    int selection_start,
+    int selection_end,
+    int cursor,
+    const std::vector<SegmentInfo>& segments,
+    std::string* error) {
+  if (!IsActive()) {
+    *error = kErrorNotActive;
+    return false;
+  }
+  if (context_id != context_id_ || context_id_ == -1) {
+    *error = kErrorWrongContext;
+    return false;
+  }
+
+  composition_cursor_ = cursor;
+  composition_text_.reset(new ui::CompositionText());
+  composition_text_->text = base::UTF8ToUTF16(text);
+
+  composition_text_->selection.set_start(selection_start);
+  composition_text_->selection.set_end(selection_end);
+
+  // TODO: Add support for displaying selected text in the composition string.
+  for (std::vector<SegmentInfo>::const_iterator segment = segments.begin();
+       segment != segments.end(); ++segment) {
+    ui::CompositionUnderline underline;
+
+    switch (segment->style) {
+      case SEGMENT_STYLE_UNDERLINE:
+        underline.color = SK_ColorBLACK;
+        break;
+      case SEGMENT_STYLE_DOUBLE_UNDERLINE:
+        underline.color = SK_ColorBLACK;
+        underline.thick = true;
+        break;
+      case SEGMENT_STYLE_NO_UNDERLINE:
+        underline.color = SK_ColorTRANSPARENT;
+        break;
+      default:
+        continue;
+    }
+
+    underline.start_offset = segment->start;
+    underline.end_offset = segment->end;
+    composition_text_->underlines.push_back(underline);
+  }
+
+  // TODO(nona): Makes focus out mode configuable, if necessary.
+  UpdateComposition(*composition_text_, composition_cursor_, true);
+  return true;
+}
+
+bool InputMethodEngineBase::ClearComposition(int context_id,
+                                             std::string* error) {
+  if (!IsActive()) {
+    *error = kErrorNotActive;
+    return false;
+  }
+  if (context_id != context_id_ || context_id_ == -1) {
+    *error = kErrorWrongContext;
+    return false;
+  }
+
+  composition_cursor_ = 0;
+  composition_text_.reset(new ui::CompositionText());
+  UpdateComposition(*composition_text_, composition_cursor_, false);
+  return true;
+}
+
+bool InputMethodEngineBase::CommitText(int context_id,
+                                       const char* text,
+                                       std::string* error) {
+  if (!IsActive()) {
+    // TODO: Commit the text anyways.
+    *error = kErrorNotActive;
+    return false;
+  }
+  if (context_id != context_id_ || context_id_ == -1) {
+    *error = kErrorWrongContext;
+    return false;
+  }
+
+  ui::IMEBridge::Get()->GetInputContextHandler()->CommitText(text);
+
+  // Records histograms for committed characters.
+  if (!composition_text_->text.empty()) {
+    size_t len = GetUtf8StringLength(text);
+    UMA_HISTOGRAM_CUSTOM_COUNTS("InputMethod.CommitLength", len, 1, 25, 25);
+    composition_text_.reset(new ui::CompositionText());
+  }
+  return true;
+}
+
+bool InputMethodEngineBase::DeleteSurroundingText(int context_id,
+                                                  int offset,
+                                                  size_t number_of_chars,
+                                                  std::string* error) {
+  if (!IsActive()) {
+    *error = kErrorNotActive;
+    return false;
+  }
+  if (context_id != context_id_ || context_id_ == -1) {
+    *error = kErrorWrongContext;
+    return false;
+  }
+
+  // TODO(nona): Return false if there is ongoing composition.
+
+  ui::IMEInputContextHandlerInterface* input_context =
+      ui::IMEBridge::Get()->GetInputContextHandler();
+  if (input_context)
+    input_context->DeleteSurroundingText(offset, number_of_chars);
+
+  return true;
+}
+
+void InputMethodEngineBase::SetCompositionBounds(
+    const std::vector<gfx::Rect>& bounds) {
+  if (!CheckProfile())

[sky, 2016/01/08 16:35:27]

Why do we need all these CheckProfile functions? If InputMethodEngine is profile
specific, shouldn't the appropriate InputMethodEngine be enabled as appropriate?

[Azure Wei, 2016/01/10 08:19:30]

I think CheckProfile() was mainly used for Disable() function. When switching
the log-in account in ChromeOS, a different InputMethodEngine could be enabled
if the two accounts selected two different input methods. The previous
InputMethodEngine::Disable() will be called, but we don't want to clear the
active component id for that profile. The CheckProfile() will return false to
not run the following codes.

I am not quite sure whether other functions need to call CheckProfile(), as I'm
just trying to keep the ChromeOS-specific codes the same as before. And I think
shuchen@ should know better about these functions.

This logic will be different on Linux and Windows desktop, as there will be only
one active input extension all the time. So I declared CheckProfile() as a
virtual function in InputMethodEngineBase. 

[sky, 2016/01/11 16:30:14]

Not sure I follow. Shouldn't there only be one inputmethod enabled at a time?

+    return;
+  observer_->OnCompositionBoundsChanged(bounds);
+}
+
+void InputMethodEngineBase::FocusIn(
+    const ui::IMEEngineHandlerInterface::InputContext& input_context) {
+  if (!CheckProfile())
+    return;
+  current_input_type_ = input_context.type;
+
+  if (!IsActive() || current_input_type_ == ui::TEXT_INPUT_TYPE_NONE)
+    return;
+
+  context_id_ = next_context_id_;
+  ++next_context_id_;
+
+  observer_->OnFocus(ui::IMEEngineHandlerInterface::InputContext(
+      context_id_, input_context.type, input_context.mode,
+      input_context.flags));
+}
+
+void InputMethodEngineBase::FocusOut() {
+  if (!CheckProfile())
+    return;
+  if (!IsActive() || current_input_type_ == ui::TEXT_INPUT_TYPE_NONE)
+    return;
+
+  current_input_type_ = ui::TEXT_INPUT_TYPE_NONE;
+
+  int context_id = context_id_;
+  context_id_ = -1;
+  observer_->OnBlur(context_id);
+}
+
+void InputMethodEngineBase::Enable(const std::string& component_id) {
+  if (!CheckProfile())
+    return;
+  DCHECK(!component_id.empty());
+  active_component_id_ = component_id;
+  observer_->OnActivate(component_id);
+  const ui::IMEEngineHandlerInterface::InputContext& input_context =
+      ui::IMEBridge::Get()->GetCurrentInputContext();
+  current_input_type_ = input_context.type;
+  FocusIn(input_context);
+}
+
+void InputMethodEngineBase::Disable() {
+  if (!CheckProfile())
+    return;
+  active_component_id_.clear();
+  if (ui::IMEBridge::Get()->GetInputContextHandler())
+    ui::IMEBridge::Get()->GetInputContextHandler()->CommitText(
+        base::UTF16ToUTF8(composition_text_->text));
+  composition_text_.reset(new ui::CompositionText());
+  observer_->OnDeactivated(active_component_id_);
+}
+
+void InputMethodEngineBase::Reset() {
+  if (!CheckProfile())
+    return;
+  composition_text_.reset(new ui::CompositionText());
+  observer_->OnReset(active_component_id_);
+}
+
+bool InputMethodEngineBase::IsInterestedInKeyEvent() const {
+  return observer_->IsInterestedInKeyEvent();
+}
+
+void InputMethodEngineBase::ProcessKeyEvent(const ui::KeyEvent& key_event,
+                                            KeyEventDoneCallback& callback) {
+  if (!CheckProfile())
+    return;
+
+  KeyboardEvent ext_event;
+  GetExtensionKeyboardEventFromKeyEvent(key_event, &ext_event);
+
+  // If the given key event is equal to the key event sent by
+  // SendKeyEvents, this engine ID is propagated to the extension IME.
+  // Note, this check relies on that ui::KeyEvent is propagated as
+  // reference without copying.
+  if (&key_event == sent_key_event_)
+    ext_event.extension_id = extension_id_;
+
+  observer_->OnKeyEvent(active_component_id_, ext_event, callback);
+}
+
+void InputMethodEngineBase::SetSurroundingText(const std::string& text,
+                                               uint32_t cursor_pos,
+                                               uint32_t anchor_pos,
+                                               uint32_t offset_pos) {
+  if (!CheckProfile())
+    return;
+  observer_->OnSurroundingTextChanged(
+      active_component_id_, text, static_cast<int>(cursor_pos),
+      static_cast<int>(anchor_pos), static_cast<int>(offset_pos));
+}
+
+}  // namespace input_method