Dictionary worker refactor (#1894)

* Rename dictionary worker files

* Rename classes

* Rename file

* Rename class

* Generalize the _invoke method

* Rename 'import' to 'importDictionary'

* Improve DictionaryImporterMediaLoader usage

* Refactor message handler

* Generalize onProgress event

5 files changed, 120 insertions, 100 deletions

diff --git a/ext/js/language/dictionary-database-modifier.js b/ext/js/language/dictionary-database-modifier.js
new file mode 100644
index 00000000..3b100fae
--- /dev/null
+++ b/ext/js/language/dictionary-database-modifier.js
@@ -0,0 +1,109 @@
+/*
+ * 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
+ * DictionaryImporterMediaLoader
+ */
+
+class DictionaryDatabaseModifier {
+    constructor() {
+        this._dictionaryImporterMediaLoader = new DictionaryImporterMediaLoader();
+    }
+
+    importDictionary(archiveContent, details, onProgress) {
+        return this._invoke('importDictionary', {details, archiveContent}, [archiveContent], onProgress);
+    }
+
+    // Private
+
+    _invoke(action, params, transfer, onProgress) {
+        return new Promise((resolve, reject) => {
+            const worker = new Worker('/js/language/dictionary-worker-main.js', {});
+            const details = {
+                complete: false,
+                worker,
+                resolve,
+                reject,
+                onMessage: null,
+                onProgress
+            };
+            const onMessage = this._onMessage.bind(this, details);
+            details.onMessage = onMessage;
+            worker.addEventListener('message', onMessage);
+            worker.postMessage({action, params}, transfer);
+        });
+    }
+
+    _onMessage(details, e) {
+        if (details.complete) { return; }
+        const {action, params} = e.data;
+        switch (action) {
+            case 'complete':
+                {
+                    const {worker, resolve, reject, onMessage} = details;
+                    details.complete = true;
+                    details.worker = null;
+                    details.resolve = null;
+                    details.reject = null;
+                    details.onMessage = null;
+                    worker.removeEventListener('message', onMessage);
+                    worker.terminate();
+                    this._onMessageComplete(params, resolve, reject);
+                }
+                break;
+            case 'progress':
+                this._onMessageProgress(params, details.onProgress);
+                break;
+            case 'getImageResolution':
+                this._onMessageGetImageResolution(params, details.worker);
+                break;
+        }
+    }
+
+    _onMessageComplete(params, resolve, reject) {
+        const {error} = params;
+        if (typeof error !== 'undefined') {
+            reject(deserializeError(error));
+        } else {
+            resolve(this._formatResult(params.result));
+        }
+    }
+
+    _onMessageProgress(params, onProgress) {
+        if (typeof onProgress !== 'function') { return; }
+        const {args} = params;
+        onProgress(...args);
+    }
+
+    async _onMessageGetImageResolution(params, worker) {
+        const {id, mediaType, content} = params;
+        let response;
+        try {
+            const result = await this._dictionaryImporterMediaLoader.getImageResolution(mediaType, content);
+            response = {id, result};
+        } catch (e) {
+            response = {id, error: serializeError(e)};
+        }
+        worker.postMessage({action: 'getImageResolution.response', params: response});
+    }
+
+    _formatResult(data) {
+        const {result, errors} = data;
+        const errors2 = errors.map((error) => deserializeError(error));
+        return {result, errors: errors2};
+    }
+}
diff --git a/ext/js/language/dictionary-importer-threaded.js b/ext/js/language/dictionary-importer-threaded.js
deleted file mode 100644
index c9b6fb24..00000000
--- a/ext/js/language/dictionary-importer-threaded.js
+++ /dev/null
@@ -1,89 +0,0 @@
-/*
- * 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
- * DictionaryImporterMediaLoader
- */
-
-class DictionaryImporterThreaded {
-    constructor(onProgress) {
-        this._onProgress = onProgress;
-    }
-
-    importDictionary(archiveContent, details) {
-        return new Promise((resolve, reject) => {
-            const dictionaryImporterMediaLoader = new DictionaryImporterMediaLoader();
-            const worker = new Worker('/js/language/dictionary-importer-worker-main.js', {});
-            const onMessage = (e) => {
-                const {action, params} = e.data;
-                switch (action) {
-                    case 'complete':
-                        worker.removeEventListener('message', onMessage);
-                        worker.terminate();
-                        this._onMessageComplete(params, resolve, reject);
-                        break;
-                    case 'progress':
-                        this._onMessageProgress(params);
-                        break;
-                    case 'getImageResolution':
-                        this._onMessageGetImageResolution(params, worker, dictionaryImporterMediaLoader);
-                        break;
-                }
-            };
-            worker.addEventListener('message', onMessage);
-            worker.postMessage({
-                action: 'import',
-                params: {details, archiveContent}
-            }, [archiveContent]);
-        });
-    }
-
-    // Private
-
-    _onMessageComplete(params, resolve, reject) {
-        const {error} = params;
-        if (typeof error !== 'undefined') {
-            reject(deserializeError(error));
-        } else {
-            resolve(this._formatResult(params.result));
-        }
-    }
-
-    _onMessageProgress(params) {
-        if (typeof this._onProgress !== 'function') { return; }
-        const {args} = params;
-        this._onProgress(...args);
-    }
-
-    async _onMessageGetImageResolution(params, worker, dictionaryImporterMediaLoader) {
-        const {id, mediaType, content} = params;
-        let response;
-        try {
-            const result = await dictionaryImporterMediaLoader.getImageResolution(mediaType, content);
-            response = {id, result};
-        } catch (e) {
-            response = {id, error: serializeError(e)};
-        }
-        worker.postMessage({action: 'getImageResolution.response', params: response});
-    }
-
-    _formatResult(data) {
-        const {result, errors} = data;
-        const errors2 = errors.map((error) => deserializeError(error));
-        return {result, errors: errors2};
-    }
-}
diff --git a/ext/js/language/dictionary-importer-worker-main.js b/ext/js/language/dictionary-worker-main.js
index 100bb4fb..e113b568 100644
--- a/ext/js/language/dictionary-importer-worker-main.js
+++ b/ext/js/language/dictionary-worker-main.js
@@ -16,7 +16,7 @@
  */
 
 /* global
- * DictionaryImporterWorker
+ * DictionaryWorker
  */
 
 self.importScripts(
@@ -27,14 +27,14 @@ self.importScripts(
     '/js/general/cache-map.js',
     '/js/language/dictionary-database.js',
     '/js/language/dictionary-importer.js',
-    '/js/language/dictionary-importer-worker.js',
-    '/js/language/dictionary-importer-worker-media-loader.js',
+    '/js/language/dictionary-worker.js',
+    '/js/language/dictionary-worker-media-loader.js',
     '/js/media/media-util.js'
 );
 
 (() => {
     try {
-        const dictionaryImporterWorker = new DictionaryImporterWorker();
+        const dictionaryImporterWorker = new DictionaryWorker();
         dictionaryImporterWorker.prepare();
     } catch (e) {
         log.error(e);
diff --git a/ext/js/language/dictionary-importer-worker-media-loader.js b/ext/js/language/dictionary-worker-media-loader.js
index 5d5d3593..90ee513f 100644
--- a/ext/js/language/dictionary-importer-worker-media-loader.js
+++ b/ext/js/language/dictionary-worker-media-loader.js
@@ -19,7 +19,7 @@
  * Class used for loading and validating media from a worker thread
  * during the dictionary import process.
  */
-class DictionaryImporterWorkerMediaLoader {
+class DictionaryWorkerMediaLoader {
     /**
      * Creates a new instance of the media loader.
      */
diff --git a/ext/js/language/dictionary-importer-worker.js b/ext/js/language/dictionary-worker.js
index 014b6542..5c482178 100644
--- a/ext/js/language/dictionary-importer-worker.js
+++ b/ext/js/language/dictionary-worker.js
@@ -18,12 +18,12 @@
 /* global
  * DictionaryDatabase
  * DictionaryImporter
- * DictionaryImporterWorkerMediaLoader
+ * DictionaryWorkerMediaLoader
  */
 
-class DictionaryImporterWorker {
+class DictionaryWorker {
     constructor() {
-        this._mediaLoader = new DictionaryImporterWorkerMediaLoader();
+        this._mediaLoader = new DictionaryWorkerMediaLoader();
     }
 
     prepare() {
@@ -35,8 +35,8 @@ class DictionaryImporterWorker {
     _onMessage(e) {
         const {action, params} = e.data;
         switch (action) {
-            case 'import':
-                this._onImport(params);
+            case 'importDictionary':
+                this._onImportDictionary(params);
                 break;
             case 'getImageResolution.response':
                 this._mediaLoader.handleMessage(params);
@@ -44,7 +44,7 @@ class DictionaryImporterWorker {
         }
     }
 
-    async _onImport({details, archiveContent}) {
+    async _onImportDictionary({details, archiveContent}) {
         const onProgress = (...args) => {
             self.postMessage({
                 action: 'progress',