Adding IBus support to cros library.

chromeos_language.cc

Index: chromeos_language.cc
diff --git a/chromeos_language.cc b/chromeos_language.cc
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+++ b/chromeos_language.cc
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+// Copyright (c) 2009 The Chromium OS 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 "chromeos_language.h"
+
+#include <base/logging.h>
+#include <ibus.h>
+
+#include <algorithm>  // for std::sort.
+
+#include "chromeos/dbus/dbus.h"
+#include "chromeos/glib/object.h"
+
+namespace {
+
+const char kCandidateWindowService[] = "org.freedesktop.IBus.Panel";
+const char kCandidateWindowObjectPath[] = "/org/chromium/Chrome/LanguageBar";
+const char kCandidateWindowInterface[] = "org.freedesktop.IBus.Panel";
+
+// Copies IME names in |engines| to |out|.
+void AddIMELanguages(const GList* engines, chromeos::InputLanguageList* out) {
+  DCHECK(out);
+  for (; engines; engines = g_list_next(engines)) {
+    IBusEngineDesc *engine_desc = IBUS_ENGINE_DESC(engines->data);
+    out->push_back(chromeos::InputLanguage(
+        chromeos::LANGUAGE_CATEGORY_IME,
+        engine_desc->name, engine_desc->longname, engine_desc->icon));
+    g_object_unref(engine_desc);
+  }
+}
+
+// Copies XKB layout names in (TBD) to |out|.
+void AddXKBLayouts(chromeos::InputLanguageList* out) {
+  DCHECK(out);
+  // TODO(yusukes): implement this.
+  out->push_back(chromeos::InputLanguage(
+      chromeos::LANGUAGE_CATEGORY_XKB,
+      kFallbackXKBId,
+      kFallbackXKBDisplayName,
+      "" /* no icon */));  // mock
+}
+
+}  // namespace
+
+namespace chromeos {
+
+// A class that holds IBus and DBus connections.
+class LanguageStatusConnection {
+ public:
+  LanguageStatusConnection(LanguageStatusMonitorFunction monitor_function,
+                           void* language_library)
+      : monitor_function_(monitor_function),
+        language_library_(language_library),
+        ibus_(NULL),
+        dbus_focus_in_(NULL),
+        dbus_focus_out_(NULL),
+        dbus_state_changed_(NULL),
+        input_context_path_("") {
+    DCHECK(monitor_function_);
+    DCHECK(language_library_);
+  }
+
+  ~LanguageStatusConnection() {
+    // Close IBus and DBus connections.
+    if (ibus_) {
+      g_object_unref(ibus_);
+    }
+    if (dbus_focus_in_) {
+      dbus::Disconnect(dbus_focus_in_);
+    }
+    if (dbus_focus_out_) {
+      dbus::Disconnect(dbus_focus_out_);
+    }
+    if (dbus_state_changed_) {
+      dbus::Disconnect(dbus_state_changed_);
+    }
+  }
+
+  // Initializes IBus and DBus connections.
+  bool Init() {
+    // Establish IBus connection between ibus-daemon to retrieve the list of
+    // available IME engines, change the current IME engine, and so on.
+    ibus_init();
+    ibus_ = ibus_bus_new();
+
+    // Check the IBus connection status.
+    if (!ibus_) {
+      LOG(ERROR) << "ibus_bus_new() failed";
+      return false;
+    }
+    if (!ibus_bus_is_connected(ibus_)) {
+      LOG(ERROR) << "ibus_bus_is_connected() failed";
+      return false;
+    }
+
+    // Establish a DBus connection between the candidate_window process for
+    // Chromium OS to handle "FocusIn", "FocusOut", and "StateChanged" signals
+    // from the process.
+    const char* address = ibus_get_address();
+    dbus::BusConnection dbus(dbus::GetPrivateBusConnection(address));
+    LOG(INFO) << "Established private D-Bus connection to: '" << address << "'";
+
+    const bool kConnectToNameOwner = true;
+    // TODO(yusukes): dbus::Proxy instantiation might fail (and abort due to
+    // DCHECK failure) when candidate_window process does not exist yet.
+    // Would be better to add "bool dbus::Proxy::Init()" or something like that
+    // to handle such case?
+    dbus::Proxy candidate_window(dbus,
+                                 kCandidateWindowService,
+                                 kCandidateWindowObjectPath,
+                                 kCandidateWindowInterface,
+                                 kConnectToNameOwner);
+
+    if (!candidate_window) {
+      LOG(ERROR) << "Can't construct proxy for the candidate window. "
+                 << "candidate window is not running?";
+      return false;
+    }
+
+    dbus_focus_in_ = dbus::Monitor(candidate_window,
+                                   "FocusIn",
+                                   &LanguageStatusConnection::FocusIn,
+                                   this);
+    dbus_focus_out_ = dbus::Monitor(candidate_window,
+                                    "FocusOut",
+                                    &LanguageStatusConnection::FocusOut,
+                                    this);
+    dbus_state_changed_ = dbus::Monitor(candidate_window,
+                                        "StateChanged",
+                                        &LanguageStatusConnection::StateChanged,
+                                        this);
+
+    // TODO(yusukes): Investigate what happens if IBus/DBus connections are
+    // suddenly closed.
+    // TODO(yusukes): Investigate what happens if candidate_window process is
+    // restarted. I'm not sure but we should use dbus_g_proxy_new_for_name(),
+    // not dbus_g_proxy_new_for_name_owner()?
+
+    return true;
+  }
+
+  // Called by cros API ChromeOSGetLanguages() and returns a list of IMEs and
+  // XKB layouts that are currently available.
+  InputLanguageList* GetLanguages() {
+    GList* engines = ibus_bus_list_active_engines(ibus_);
+    if (!engines) {
+      // IBus connection is broken?
+      LOG(ERROR) << "ibus_bus_list_active_engines() failed.";
+      return NULL;
+    }
+    InputLanguageList* language_list = new InputLanguageList;
+    AddIMELanguages(engines, language_list);
+    AddXKBLayouts(language_list);
+    std::sort(language_list->begin(), language_list->end());
+
+    g_list_free(engines);
+    return language_list;
+  }
+
+  // Called by cros API ChromeOSChangeLanguage().
+  void SwitchXKB(const char* name) {
+    IBusInputContext* context
+        = ibus_input_context_get_input_context(input_context_path_.c_str(),
+                                               ibus_bus_get_connection(ibus_));
+    ibus_input_context_disable(context);
+    g_object_unref(context);
+    // TODO(yusukes): implement XKB switching.
+    UpdateUI();
+  }
+
+  // Called by cros API ChromeOSChangeLanguage() as well.
+  void SwitchIME(const char* name) {
+    if (input_context_path_.empty()) {
+      LOG(ERROR) << "Input context is unknown";
+      return;
+    }
+
+    IBusInputContext* context
+        = ibus_input_context_get_input_context(input_context_path_.c_str(),
+                                               ibus_bus_get_connection(ibus_));
+    ibus_input_context_set_engine(context, name);
+    g_object_unref(context);
+    UpdateUI();
+  }
+
+ private:
+  // Handles "FocusIn" signal from candidate_window.
+  static void FocusIn(void* object, const char* input_context_path) {
+    DCHECK(input_context_path) << "NULL context passed";
+    DLOG(INFO) << "FocusIn: " << input_context_path;
+    DCHECK(object);
+
+    // Remember the current ic path.
+    LanguageStatusConnection* self
+        = static_cast<LanguageStatusConnection*>(object);
+    self->input_context_path_ = input_context_path;
+    self->UpdateUI();  // This is necessary since IME status is held per ic.
+  }
+
+  // Handles "FocusOut" signal from candidate_window.
+  static void FocusOut(void* object, const char* input_context_path) {
+    DCHECK(input_context_path) << "NULL context passed";
+    DLOG(INFO) << "FocusOut: " << input_context_path;
+    DCHECK(object);
+  }
+
+  // Handles "StateChanged" signal from candidate_window process.
+  static void StateChanged(void* object, const char* dummy) {
+    // TODO(yusukes): Modify common/chromeos/dbus/dbus.h so that we can handle
+    // signals without argument. Then remove the |dummy|.
+    DLOG(INFO) << "StateChanged";
+    DCHECK(object);
+    LanguageStatusConnection* self
+        = static_cast<LanguageStatusConnection*>(object);
+    self->UpdateUI();
+  }
+
+  // Retrieve IME/XKB status and notify them to the UI.
+  void UpdateUI() {
+    if (input_context_path_.empty()) {
+      LOG(ERROR) << "Input context is unknown";
+      return;
+    }
+
+    IBusInputContext* context
+        = ibus_input_context_get_input_context(
+            input_context_path_.c_str(), ibus_bus_get_connection(ibus_));
+
+    InputLanguage current_language;
+    const bool ime_is_enabled = ibus_input_context_is_enabled(context);
+    if (ime_is_enabled) {
+      DLOG(INFO) << "IME is active";
+      // Set IME name on current_language.
+      const IBusEngineDesc* engine_desc
+          = ibus_input_context_get_engine(context);
+      DCHECK(engine_desc);
+      if (!engine_desc) {
+        return;
+      }
+      current_language = InputLanguage(LANGUAGE_CATEGORY_IME,
+                                       engine_desc->name,
+                                       engine_desc->longname,
+                                       engine_desc->icon);
+    } else {
+      DLOG(INFO) << "IME is not active";
+      // Set XKB layout name on current_languages.
+      current_language = InputLanguage(LANGUAGE_CATEGORY_XKB,
+                                       kFallbackXKBId,
+                                       kFallbackXKBDisplayName,
+                                       "" /* no icon */);  // mock
+      // TODO(yusukes): implemente this.
+    }
+    DLOG(INFO) << "Updating the UI. ID:" << current_language.id
+               << ", display_name:" << current_language.display_name;
+
+    // Notify the change to update UI.
+    monitor_function_(language_library_, current_language);
+    g_object_unref(context);
+  }
+
+  // A function pointer which points LanguageLibrary::LanguageChangedHandler
+  // function. |monitor_funcion_| is called when Chrome UI needs to be updated.
+  LanguageStatusMonitorFunction monitor_function_;
+  // Points to a chromeos::LanguageLibrary object. |language_library_| is used
+  // as the first argument of the |monitor_function_| function.
+  void* language_library_;
+
+  // Connections to IBus and DBus.
+  typedef dbus::MonitorConnection<void (const char*)>* DBusConnectionType;
+  IBusBus* ibus_;
+  DBusConnectionType dbus_focus_in_;
+  DBusConnectionType dbus_focus_out_;
+  DBusConnectionType dbus_state_changed_;
+
+  // Current input context path.
+  std::string input_context_path_;
+};
+
+//
+// cros APIs
+//
+
+// The function will be bound to chromeos::MonitorLanguageStatus with dlsym()
+// in load.cc so it needs to be in the C linkage, so the symbol name does not
+// get mangled.
+extern "C"
+LanguageStatusConnection* ChromeOSMonitorLanguageStatus(
+    LanguageStatusMonitorFunction monitor_function, void* language_library) {
+  LOG(INFO) << "MonitorLanguageStatus";
+  LanguageStatusConnection* connection
+      = new LanguageStatusConnection(monitor_function, language_library);
+  if (!connection->Init()) {
+    LOG(WARNING) << "Failed to Init() LanguageStatusConnection. "
+                 << "Returning NULL";
+    delete connection;
+    connection = NULL;
+  }
+  return connection;
+}
+
+extern "C"
+void ChromeOSDisconnectLanguageStatus(LanguageStatusConnection* connection) {
+  LOG(INFO) << "DisconnectLanguageStatus";
+  delete connection;
+}
+
+extern "C"
+InputLanguageList* ChromeOSGetLanguages(LanguageStatusConnection* connection) {
+  // TODO(yusukes): Add DCHECK(connection); here when candidate_window for
+  // Chrome OS gets ready.
+  if (!connection) {
+    LOG(WARNING) << "LanguageStatusConnection is NULL";
+    return NULL;
+  }
+  // Pass ownership to a caller. Note: GetLanguages() might return NULL.
+  return connection->GetLanguages();
+}
+
+extern "C"
+void ChromeOSChangeLanguage(LanguageStatusConnection* connection,
+                            LanguageCategory category,
+                            const char* name) {
+  // TODO(yusukes): Add DCHECK(connection); here when candidate_window for
+  // Chrome OS gets ready.
+  if (!connection) {
+    LOG(WARNING) << "LanguageStatusConnection is NULL";
+    return;
+  }
+  DCHECK(name);
+  DLOG(INFO) << "ChangeLanguage: " << name << " [category " << category << "]";
+  switch (category) {
+    case LANGUAGE_CATEGORY_XKB:
+      connection->SwitchXKB(name);
+      break;
+    case LANGUAGE_CATEGORY_IME:
+      connection->SwitchIME(name);
+      break;
+  }
+}
+
+}  // namespace chromeos