4 files changed, 153 insertions, 1 deletions

diff --git a/ext/bg/js/backend.js b/ext/bg/js/backend.js
index 67b17cc9..f1983cb3 100644
--- a/ext/bg/js/backend.js
+++ b/ext/bg/js/backend.js
@@ -122,7 +122,8 @@ class Backend {
             ['setAllSettings',               {async: true,  contentScript: false, handler: this._onApiSetAllSettings.bind(this)}],
             ['getOrCreateSearchPopup',       {async: true,  contentScript: true,  handler: this._onApiGetOrCreateSearchPopup.bind(this)}],
             ['isTabSearchPopup',             {async: true,  contentScript: true,  handler: this._onApiIsTabSearchPopup.bind(this)}],
-            ['triggerDatabaseUpdated',       {async: false, contentScript: true,  handler: this._onApiTriggerDatabaseUpdated.bind(this)}]
+            ['triggerDatabaseUpdated',       {async: false, contentScript: true,  handler: this._onApiTriggerDatabaseUpdated.bind(this)}],
+            ['testMecab',                    {async: true,  contentScript: true,  handler: this._onApiTestMecab.bind(this)}]
         ]);
         this._messageHandlersWithProgress = new Map([
         ]);
@@ -676,6 +677,42 @@ class Backend {
         this._triggerDatabaseUpdated(type, cause);
     }
 
+    async _onApiTestMecab() {
+        if (!this._mecab.isEnabled()) {
+            throw new Error('MeCab not enabled');
+        }
+
+        let permissionsOkay = false;
+        try {
+            permissionsOkay = await this._hasPermissions({permissions: ['nativeMessaging']});
+        } catch (e) {
+            // NOP
+        }
+        if (!permissionsOkay) {
+            throw new Error('Insufficient permissions');
+        }
+
+        const disconnect = !this._mecab.isConnected();
+        try {
+            const version = await this._mecab.getVersion();
+            if (version === null) {
+                throw new Error('Could not connect to native MeCab component');
+            }
+
+            const localVersion = this._mecab.getLocalVersion();
+            if (version !== localVersion) {
+                throw new Error(`MeCab component version not supported: ${version}`);
+            }
+        } finally {
+            // Disconnect if the connection was previously disconnected
+            if (disconnect && this._mecab.isEnabled() && this._mecab.isActive()) {
+                this._mecab.disconnect();
+            }
+        }
+
+        return true;
+    }
+
     // Command handlers
 
     async _onCommandOpenSearchPage(params) {
@@ -1904,4 +1941,15 @@ class Backend {
             });
         });
     }
+
+    _hasPermissions(permissions) {
+        return new Promise((resolve, reject) => chrome.permissions.contains(permissions, (result) => {
+            const e = chrome.runtime.lastError;
+            if (e) {
+                reject(new Error(e.message));
+            } else {
+                resolve(result);
+            }
+        }));
+    }
 }
diff --git a/ext/bg/js/mecab.js b/ext/bg/js/mecab.js
index ef5d6821..4eff2927 100644
--- a/ext/bg/js/mecab.js
+++ b/ext/bg/js/mecab.js
@@ -54,6 +54,39 @@ class Mecab {
     }
 
     /**
+     * Disconnects the current port, but does not disable future connections.
+     */
+    disconnect() {
+        if (this._port !== null) {
+            this._clearPort();
+        }
+    }
+
+    /**
+     * Returns whether or not the connection to the native application is active.
+     * @returns `true` if the connection is active, `false` otherwise.
+     */
+    isConnected() {
+        return (this._port !== null);
+    }
+
+    /**
+     * Returns whether or not any invocation is currently active.
+     * @returns `true` if an invocation is active, `false` otherwise.
+     */
+    isActive() {
+        return (this._invocations.size > 0);
+    }
+
+    /**
+     * Gets the local API version being used.
+     * @returns An integer representing the API version that Yomichan uses.
+     */
+    getLocalVersion() {
+        return this._version;
+    }
+
+    /**
      * Gets the version of the MeCab component.
      * @returns The version of the MeCab component, or `null` if the component was not found.
      */
diff --git a/ext/bg/js/settings2/mecab-controller.js b/ext/bg/js/settings2/mecab-controller.js
new file mode 100644
index 00000000..ff2a4a66
--- /dev/null
+++ b/ext/bg/js/settings2/mecab-controller.js
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2021  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/* global
+ * api
+ */
+
+class MecabController {
+    constructor(settingsController) {
+        this._settingsController = settingsController;
+        this._testButton = null;
+        this._resultsContainer = null;
+        this._testActive = false;
+    }
+
+    prepare() {
+        this._testButton = document.querySelector('#test-mecab-button');
+        this._resultsContainer = document.querySelector('#test-mecab-results');
+
+        this._testButton.addEventListener('click', this._onTestButtonClick.bind(this), false);
+    }
+
+    // Private
+
+    _onTestButtonClick(e) {
+        e.preventDefault();
+        this._testMecab();
+    }
+
+    async _testMecab() {
+        if (this._testActive) { return; }
+
+        try {
+            this._testActive = true;
+            this._testButton.disabled = true;
+            this._resultsContainer.textContent = '';
+            this._resultsContainer.hidden = true;
+            await api.testMecab();
+            this._setStatus('Connection was successful', false);
+        } catch (e) {
+            this._setStatus(e.message, true);
+        } finally {
+            this._testActive = false;
+            this._testButton.disabled = false;
+        }
+    }
+
+    _setStatus(message, isError) {
+        this._resultsContainer.textContent = message;
+        this._resultsContainer.hidden = false;
+        this._resultsContainer.classList.toggle('danger-text', isError);
+    }
+}
diff --git a/ext/bg/js/settings2/settings-main.js b/ext/bg/js/settings2/settings-main.js
index f4a38d85..24248110 100644
--- a/ext/bg/js/settings2/settings-main.js
+++ b/ext/bg/js/settings2/settings-main.js
@@ -26,6 +26,7 @@
  * ExtensionKeyboardShortcutController
  * GenericSettingController
  * KeyboardShortcutController
+ * MecabController
  * ModalController
  * NestedPopupsController
  * PermissionsToggleController
@@ -140,6 +141,9 @@ async function setupGenericSettingsController(genericSettingController) {
         const popupWindowController = new PopupWindowController();
         popupWindowController.prepare();
 
+        const mecabController = new MecabController();
+        mecabController.prepare();
+
         await Promise.all(preparePromises);
 
         document.documentElement.dataset.loaded = 'true';