root/ui/base/ime/input_method_chromeos.cc

DEFINITIONS

1. GetEngine
2. weak_ptr_factory_
3. OnFocus
4. OnBlur
5. OnUntranslatedIMEMessage
6. ProcessKeyEventDone
7. DispatchKeyEvent
8. OnTextInputTypeChanged
9. OnCaretBoundsChanged
10. CancelComposition
11. OnInputLocaleChanged
12. GetInputLocale
13. IsActive
14. IsCandidatePopupOpen
15. OnWillChangeFocusedClient
16. OnDidChangeFocusedClient
17. ConfirmCompositionText
18. ResetContext
19. UpdateContextFocusState
20. ProcessKeyEventPostIME
21. ProcessFilteredKeyPressEvent
22. ProcessUnfilteredKeyPressEvent
23. ProcessInputMethodResult
24. NeedInsertChar
25. HasInputMethodResult
26. AbandonAllPendingKeyEvents
27. CommitText
28. UpdateCompositionText
29. HidePreeditText
30. DeleteSurroundingText
31. ExecuteCharacterComposer
32. ExtractCompositionText

// 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 "ui/base/ime/input_method_chromeos.h"

#include <algorithm>
#include <cstring>
#include <set>
#include <vector>

#include "base/basictypes.h"
#include "base/bind.h"
#include "base/i18n/char_iterator.h"
#include "base/logging.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/third_party/icu/icu_utf.h"
#include "chromeos/ime/composition_text.h"
#include "chromeos/ime/input_method_descriptor.h"
#include "chromeos/ime/input_method_manager.h"
#include "ui/base/ime/text_input_client.h"
#include "ui/events/event.h"
#include "ui/events/event_constants.h"
#include "ui/events/event_utils.h"
#include "ui/events/keycodes/keyboard_code_conversion.h"
#include "ui/events/keycodes/keyboard_code_conversion_x.h"
#include "ui/events/keycodes/keyboard_codes.h"
#include "ui/gfx/rect.h"

namespace {
chromeos::IMEEngineHandlerInterface* GetEngine() {
  return chromeos::IMEBridge::Get()->GetCurrentEngineHandler();
}
}  // namespace

namespace ui {

// InputMethodChromeOS implementation -----------------------------------------
InputMethodChromeOS::InputMethodChromeOS(
    internal::InputMethodDelegate* delegate)
    : context_focused_(false),
      composing_text_(false),
      composition_changed_(false),
      current_keyevent_id_(0),
      previous_textinput_type_(TEXT_INPUT_TYPE_NONE),
      weak_ptr_factory_(this) {
  SetDelegate(delegate);
  chromeos::IMEBridge::Get()->SetInputContextHandler(this);

  UpdateContextFocusState();
  OnInputMethodChanged();
}

InputMethodChromeOS::~InputMethodChromeOS() {
  AbandonAllPendingKeyEvents();
  context_focused_ = false;
  ConfirmCompositionText();
  // We are dead, so we need to ask the client to stop relying on us.
  OnInputMethodChanged();

  chromeos::IMEBridge::Get()->SetInputContextHandler(NULL);
}

void InputMethodChromeOS::OnFocus() {
  InputMethodBase::OnFocus();
  UpdateContextFocusState();
}

void InputMethodChromeOS::OnBlur() {
  ConfirmCompositionText();
  InputMethodBase::OnBlur();
  UpdateContextFocusState();
}

bool InputMethodChromeOS::OnUntranslatedIMEMessage(
    const base::NativeEvent& event,
    NativeEventResult* result) {
  return false;
}

void InputMethodChromeOS::ProcessKeyEventDone(uint32 id,
                                              ui::KeyEvent* event,
                                              bool is_handled) {
  if (pending_key_events_.find(id) == pending_key_events_.end())
   return;  // Abandoned key event.

  DCHECK(event);
  if (event->type() == ET_KEY_PRESSED) {
    if (is_handled) {
      // IME event has a priority to be handled, so that character composer
      // should be reset.
      character_composer_.Reset();
    } else {
      // If IME does not handle key event, passes keyevent to character composer
      // to be able to compose complex characters.
      is_handled = ExecuteCharacterComposer(*event);
    }
  }

  if (event->type() == ET_KEY_PRESSED || event->type() == ET_KEY_RELEASED)
    ProcessKeyEventPostIME(*event, is_handled);

  // ProcessKeyEventPostIME may change the |pending_key_events_|.
  pending_key_events_.erase(id);
}

bool InputMethodChromeOS::DispatchKeyEvent(const ui::KeyEvent& event) {
  DCHECK(event.type() == ET_KEY_PRESSED || event.type() == ET_KEY_RELEASED);
  DCHECK(system_toplevel_window_focused());

  // If |context_| is not usable, then we can only dispatch the key event as is.
  // We also dispatch the key event directly if the current text input type is
  // TEXT_INPUT_TYPE_PASSWORD, to bypass the input method.
  // Note: We need to send the key event to ibus even if the |context_| is not
  // enabled, so that ibus can have a chance to enable the |context_|.
  if (!context_focused_ || !GetEngine() ||
      GetTextInputType() == TEXT_INPUT_TYPE_PASSWORD ) {
    if (event.type() == ET_KEY_PRESSED) {
      if (ExecuteCharacterComposer(event)) {
        // Treating as PostIME event if character composer handles key event and
        // generates some IME event,
        ProcessKeyEventPostIME(event, true);
        return true;
      }
      ProcessUnfilteredKeyPressEvent(event);
    } else {
      DispatchKeyEventPostIME(event);
    }
    return true;
  }

  pending_key_events_.insert(current_keyevent_id_);

  ui::KeyEvent* copied_event = new ui::KeyEvent(event);
  GetEngine()->ProcessKeyEvent(
      event,
      base::Bind(&InputMethodChromeOS::ProcessKeyEventDone,
                 weak_ptr_factory_.GetWeakPtr(),
                 current_keyevent_id_,
                 // Pass the ownership of |copied_event|.
                 base::Owned(copied_event)));

  ++current_keyevent_id_;
  return true;
}

void InputMethodChromeOS::OnTextInputTypeChanged(
    const TextInputClient* client) {
  if (IsTextInputClientFocused(client)) {
    ResetContext();
    UpdateContextFocusState();
    if (previous_textinput_type_ != client->GetTextInputType())
      OnInputMethodChanged();
    previous_textinput_type_ = client->GetTextInputType();
  }
  InputMethodBase::OnTextInputTypeChanged(client);
}

void InputMethodChromeOS::OnCaretBoundsChanged(const TextInputClient* client) {
  if (!context_focused_ || !IsTextInputClientFocused(client))
    return;

  // The current text input type should not be NONE if |context_| is focused.
  DCHECK(!IsTextInputTypeNone());
  const gfx::Rect rect = GetTextInputClient()->GetCaretBounds();

  gfx::Rect composition_head;
  if (!GetTextInputClient()->GetCompositionCharacterBounds(0,
                                                           &composition_head)) {
    composition_head = rect;
  }

  chromeos::IMECandidateWindowHandlerInterface* candidate_window =
      chromeos::IMEBridge::Get()->GetCandidateWindowHandler();
  if (!candidate_window)
    return;
  candidate_window->SetCursorBounds(rect, composition_head);

  gfx::Range text_range;
  gfx::Range selection_range;
  base::string16 surrounding_text;
  if (!GetTextInputClient()->GetTextRange(&text_range) ||
      !GetTextInputClient()->GetTextFromRange(text_range, &surrounding_text) ||
      !GetTextInputClient()->GetSelectionRange(&selection_range)) {
    previous_surrounding_text_.clear();
    previous_selection_range_ = gfx::Range::InvalidRange();
    return;
  }

  if (previous_selection_range_ == selection_range &&
      previous_surrounding_text_ == surrounding_text)
    return;

  previous_selection_range_ = selection_range;
  previous_surrounding_text_ = surrounding_text;

  if (!selection_range.IsValid()) {
    // TODO(nona): Ideally selection_range should not be invalid.
    // TODO(nona): If javascript changes the focus on page loading, even (0,0)
    //             can not be obtained. Need investigation.
    return;
  }

  // Here SetSurroundingText accepts relative position of |surrounding_text|, so
  // we have to convert |selection_range| from node coordinates to
  // |surrounding_text| coordinates.
  if (!GetEngine())
    return;
  GetEngine()->SetSurroundingText(base::UTF16ToUTF8(surrounding_text),
                                  selection_range.start() - text_range.start(),
                                  selection_range.end() - text_range.start());
}

void InputMethodChromeOS::CancelComposition(const TextInputClient* client) {
  if (context_focused_ && IsTextInputClientFocused(client))
    ResetContext();
}

void InputMethodChromeOS::OnInputLocaleChanged() {
  // Not supported.
}

std::string InputMethodChromeOS::GetInputLocale() {
  // Not supported.
  return "";
}

bool InputMethodChromeOS::IsActive() {
  return true;
}

bool InputMethodChromeOS::IsCandidatePopupOpen() const {
  // TODO(yukishiino): Implement this method.
  return false;
}

void InputMethodChromeOS::OnWillChangeFocusedClient(
    TextInputClient* focused_before,
    TextInputClient* focused) {
  ConfirmCompositionText();
}

void InputMethodChromeOS::OnDidChangeFocusedClient(
    TextInputClient* focused_before,
    TextInputClient* focused) {
  // Force to update the input type since client's TextInputStateChanged()
  // function might not be called if text input types before the client loses
  // focus and after it acquires focus again are the same.
  OnTextInputTypeChanged(focused);

  UpdateContextFocusState();
  // Force to update caret bounds, in case the client thinks that the caret
  // bounds has not changed.
  OnCaretBoundsChanged(focused);
}

void InputMethodChromeOS::ConfirmCompositionText() {
  TextInputClient* client = GetTextInputClient();
  if (client && client->HasCompositionText())
    client->ConfirmCompositionText();

  ResetContext();
}

void InputMethodChromeOS::ResetContext() {
  if (!context_focused_ || !GetTextInputClient())
    return;

  DCHECK(system_toplevel_window_focused());

  composition_.Clear();
  result_text_.clear();
  composing_text_ = false;
  composition_changed_ = false;

  // We need to abandon all pending key events, but as above comment says, there
  // is no reliable way to abandon all results generated by these abandoned key
  // events.
  AbandonAllPendingKeyEvents();

  // This function runs asynchronously.
  // Note: some input method engines may not support reset method, such as
  // ibus-anthy. But as we control all input method engines by ourselves, we can
  // make sure that all of the engines we are using support it correctly.
  if (GetEngine())
    GetEngine()->Reset();

  character_composer_.Reset();
}

void InputMethodChromeOS::UpdateContextFocusState() {
  const bool old_context_focused = context_focused_;
  const TextInputType current_text_input_type = GetTextInputType();
  // Use switch here in case we are going to add more text input types.
  switch (current_text_input_type) {
    case TEXT_INPUT_TYPE_NONE:
    case TEXT_INPUT_TYPE_PASSWORD:
      context_focused_ = false;
      break;
    default:
      context_focused_ = true;
      break;
  }

  // Propagate the focus event to the candidate window handler which also
  // manages the input method mode indicator.
  chromeos::IMECandidateWindowHandlerInterface* candidate_window =
      chromeos::IMEBridge::Get()->GetCandidateWindowHandler();
  if (candidate_window)
    candidate_window->FocusStateChanged(context_focused_);

  if (!GetEngine())
    return;

  // We only focus in |context_| when the focus is in a normal textfield.
  // Even if focus is not changed, a text input type change causes a focus
  // blink.
  // ibus_input_context_focus_{in|out}() run asynchronously.
  bool input_type_change =
      (current_text_input_type != previous_textinput_type_);
  if (old_context_focused && (!context_focused_ || input_type_change))
    GetEngine()->FocusOut();
  if (context_focused_ && (!old_context_focused || input_type_change)) {
    chromeos::IMEEngineHandlerInterface::InputContext context(
        current_text_input_type, GetTextInputMode());
    GetEngine()->FocusIn(context);
    OnCaretBoundsChanged(GetTextInputClient());
  }
}

void InputMethodChromeOS::ProcessKeyEventPostIME(
    const ui::KeyEvent& event,
    bool handled) {
  TextInputClient* client = GetTextInputClient();
  if (!client) {
    // As ibus works asynchronously, there is a chance that the focused client
    // loses focus before this method gets called.
    DispatchKeyEventPostIME(event);
    return;
  }

  if (event.type() == ET_KEY_PRESSED && handled)
    ProcessFilteredKeyPressEvent(event);

  // In case the focus was changed by the key event. The |context_| should have
  // been reset when the focused window changed.
  if (client != GetTextInputClient())
    return;

  if (HasInputMethodResult())
    ProcessInputMethodResult(event, handled);

  // In case the focus was changed when sending input method results to the
  // focused window.
  if (client != GetTextInputClient())
    return;

  if (event.type() == ET_KEY_PRESSED && !handled)
    ProcessUnfilteredKeyPressEvent(event);
  else if (event.type() == ET_KEY_RELEASED)
    DispatchKeyEventPostIME(event);
}

void InputMethodChromeOS::ProcessFilteredKeyPressEvent(
    const ui::KeyEvent& event) {
  if (NeedInsertChar()) {
    DispatchKeyEventPostIME(event);
  } else {
    const ui::KeyEvent fabricated_event(ET_KEY_PRESSED,
                                        VKEY_PROCESSKEY,
                                        event.flags(),
                                        false);  // is_char
    DispatchKeyEventPostIME(fabricated_event);
  }
}

void InputMethodChromeOS::ProcessUnfilteredKeyPressEvent(
    const ui::KeyEvent& event) {
  const TextInputClient* prev_client = GetTextInputClient();
  DispatchKeyEventPostIME(event);

  // We shouldn't dispatch the character anymore if the key event dispatch
  // caused focus change. For example, in the following scenario,
  // 1. visit a web page which has a <textarea>.
  // 2. click Omnibox.
  // 3. enable Korean IME, press A, then press Tab to move the focus to the web
  //    page.
  // We should return here not to send the Tab key event to RWHV.
  TextInputClient* client = GetTextInputClient();
  if (!client || client != prev_client)
    return;

  // If a key event was not filtered by |context_| and |character_composer_|,
  // then it means the key event didn't generate any result text. So we need
  // to send corresponding character to the focused text input client.
  const uint32 event_flags = event.flags();
  uint16 ch = 0;
  if (event.HasNativeEvent()) {
    const base::NativeEvent& native_event = event.native_event();

    if (!(event_flags & ui::EF_CONTROL_DOWN))
      ch = ui::GetCharacterFromXEvent(native_event);
    if (!ch) {
      ch = ui::GetCharacterFromKeyCode(
          ui::KeyboardCodeFromNative(native_event), event_flags);
    }
  } else {
    ch = ui::GetCharacterFromKeyCode(event.key_code(), event_flags);
  }

  if (ch)
    client->InsertChar(ch, event_flags);
}

void InputMethodChromeOS::ProcessInputMethodResult(const ui::KeyEvent& event,
                                               bool handled) {
  TextInputClient* client = GetTextInputClient();
  DCHECK(client);

  if (result_text_.length()) {
    if (handled && NeedInsertChar()) {
      for (base::string16::const_iterator i = result_text_.begin();
           i != result_text_.end(); ++i) {
        client->InsertChar(*i, event.flags());
      }
    } else {
      client->InsertText(result_text_);
      composing_text_ = false;
    }
  }

  if (composition_changed_ && !IsTextInputTypeNone()) {
    if (composition_.text.length()) {
      composing_text_ = true;
      client->SetCompositionText(composition_);
    } else if (result_text_.empty()) {
      client->ClearCompositionText();
    }
  }

  // We should not clear composition text here, as it may belong to the next
  // composition session.
  result_text_.clear();
  composition_changed_ = false;
}

bool InputMethodChromeOS::NeedInsertChar() const {
  return GetTextInputClient() &&
      (IsTextInputTypeNone() ||
       (!composing_text_ && result_text_.length() == 1));
}

bool InputMethodChromeOS::HasInputMethodResult() const {
  return result_text_.length() || composition_changed_;
}

void InputMethodChromeOS::AbandonAllPendingKeyEvents() {
  pending_key_events_.clear();
}

void InputMethodChromeOS::CommitText(const std::string& text) {
  if (text.empty())
    return;

  // We need to receive input method result even if the text input type is
  // TEXT_INPUT_TYPE_NONE, to make sure we can always send correct
  // character for each key event to the focused text input client.
  if (!GetTextInputClient())
    return;

  const base::string16 utf16_text = base::UTF8ToUTF16(text);
  if (utf16_text.empty())
    return;

  // Append the text to the buffer, because commit signal might be fired
  // multiple times when processing a key event.
  result_text_.append(utf16_text);

  // If we are not handling key event, do not bother sending text result if the
  // focused text input client does not support text input.
  if (pending_key_events_.empty() && !IsTextInputTypeNone()) {
    GetTextInputClient()->InsertText(utf16_text);
    result_text_.clear();
  }
}

void InputMethodChromeOS::UpdateCompositionText(
    const chromeos::CompositionText& text,
    uint32 cursor_pos,
    bool visible) {
  if (IsTextInputTypeNone())
    return;

  if (!CanComposeInline()) {
    chromeos::IMECandidateWindowHandlerInterface* candidate_window =
        chromeos::IMEBridge::Get()->GetCandidateWindowHandler();
    if (candidate_window)
      candidate_window->UpdatePreeditText(text.text(), cursor_pos, visible);
  }

  // |visible| argument is very confusing. For example, what's the correct
  // behavior when:
  // 1. OnUpdatePreeditText() is called with a text and visible == false, then
  // 2. OnShowPreeditText() is called afterwards.
  //
  // If it's only for clearing the current preedit text, then why not just use
  // OnHidePreeditText()?
  if (!visible) {
    HidePreeditText();
    return;
  }

  ExtractCompositionText(text, cursor_pos, &composition_);

  composition_changed_ = true;

  // In case OnShowPreeditText() is not called.
  if (composition_.text.length())
    composing_text_ = true;

  // If we receive a composition text without pending key event, then we need to
  // send it to the focused text input client directly.
  if (pending_key_events_.empty()) {
    GetTextInputClient()->SetCompositionText(composition_);
    composition_changed_ = false;
    composition_.Clear();
  }
}

void InputMethodChromeOS::HidePreeditText() {
  if (composition_.text.empty() || IsTextInputTypeNone())
    return;

  // Intentionally leaves |composing_text_| unchanged.
  composition_changed_ = true;
  composition_.Clear();

  if (pending_key_events_.empty()) {
    TextInputClient* client = GetTextInputClient();
    if (client && client->HasCompositionText())
      client->ClearCompositionText();
    composition_changed_ = false;
  }
}

void InputMethodChromeOS::DeleteSurroundingText(int32 offset, uint32 length) {
  if (!composition_.text.empty())
    return;  // do nothing if there is ongoing composition.
  if (offset < 0 && static_cast<uint32>(-1 * offset) != length)
    return;  // only preceding text can be deletable.
  if (GetTextInputClient())
    GetTextInputClient()->ExtendSelectionAndDelete(length, 0U);
}

bool InputMethodChromeOS::ExecuteCharacterComposer(const ui::KeyEvent& event) {
  if (!character_composer_.FilterKeyPress(event))
    return false;

  // CharacterComposer consumed the key event.  Update the composition text.
  chromeos::CompositionText preedit;
  preedit.set_text(character_composer_.preedit_string());
  UpdateCompositionText(preedit, preedit.text().size(),
                        !preedit.text().empty());
  std::string commit_text =
      base::UTF16ToUTF8(character_composer_.composed_character());
  if (!commit_text.empty()) {
    CommitText(commit_text);
  }
  return true;
}

void InputMethodChromeOS::ExtractCompositionText(
    const chromeos::CompositionText& text,
    uint32 cursor_position,
    CompositionText* out_composition) const {
  out_composition->Clear();
  out_composition->text = text.text();

  if (out_composition->text.empty())
    return;

  // ibus uses character index for cursor position and attribute range, but we
  // use char16 offset for them. So we need to do conversion here.
  std::vector<size_t> char16_offsets;
  size_t length = out_composition->text.length();
  base::i18n::UTF16CharIterator char_iterator(&out_composition->text);
  do {
    char16_offsets.push_back(char_iterator.array_pos());
  } while (char_iterator.Advance());

  // The text length in Unicode characters.
  uint32 char_length = static_cast<uint32>(char16_offsets.size());
  // Make sure we can convert the value of |char_length| as well.
  char16_offsets.push_back(length);

  size_t cursor_offset =
      char16_offsets[std::min(char_length, cursor_position)];

  out_composition->selection = gfx::Range(cursor_offset);

  const std::vector<chromeos::CompositionText::UnderlineAttribute>&
      underline_attributes = text.underline_attributes();
  if (!underline_attributes.empty()) {
    for (size_t i = 0; i < underline_attributes.size(); ++i) {
      const uint32 start = underline_attributes[i].start_index;
      const uint32 end = underline_attributes[i].end_index;
      if (start >= end)
        continue;
      CompositionUnderline underline(
          char16_offsets[start], char16_offsets[end],
          SK_ColorBLACK, false /* thick */);
      if (underline_attributes[i].type ==
          chromeos::CompositionText::COMPOSITION_TEXT_UNDERLINE_DOUBLE)
        underline.thick = true;
      else if (underline_attributes[i].type ==
               chromeos::CompositionText::COMPOSITION_TEXT_UNDERLINE_ERROR)
        underline.color = SK_ColorRED;
      out_composition->underlines.push_back(underline);
    }
  }

  DCHECK(text.selection_start() <= text.selection_end());
  if (text.selection_start() < text.selection_end()) {
    const uint32 start = text.selection_start();
    const uint32 end = text.selection_end();
    CompositionUnderline underline(
        char16_offsets[start], char16_offsets[end],
        SK_ColorBLACK, true /* thick */);
    out_composition->underlines.push_back(underline);

    // If the cursor is at start or end of this underline, then we treat
    // it as the selection range as well, but make sure to set the cursor
    // position to the selection end.
    if (underline.start_offset == cursor_offset) {
      out_composition->selection.set_start(underline.end_offset);
      out_composition->selection.set_end(cursor_offset);
    } else if (underline.end_offset == cursor_offset) {
      out_composition->selection.set_start(underline.start_offset);
      out_composition->selection.set_end(cursor_offset);
    }
  }

  // Use a black thin underline by default.
  if (out_composition->underlines.empty()) {
    out_composition->underlines.push_back(CompositionUnderline(
        0, length, SK_ColorBLACK, false /* thick */));
  }
}

}  // namespace ui