DictionaryImporterMediaLoader (#1860)

* Rename param for consistency

* Move media loading functionality into DictionaryImporterMediaLoader

* Create test class for media loading

* Remove unnecessary Blob/Image/URL functionality

2 files changed, 62 insertions, 36 deletions

diff --git a/ext/js/language/dictionary-importer-media-loader.js b/ext/js/language/dictionary-importer-media-loader.js
new file mode 100644
index 00000000..bbcc5476
--- /dev/null
+++ b/ext/js/language/dictionary-importer-media-loader.js
@@ -0,0 +1,57 @@
+/*
+ * 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
+ * MediaUtil
+ */
+
+/**
+ * Class used for loading and validating media during the dictionary import process.
+ */
+class DictionaryImporterMediaLoader {
+    /**
+     * Attempts to load an image using a base64 encoded content and a media type
+     * and returns its resolution.
+     * @param mediaType The media type for the image content.
+     * @param content The binary content for the image, encoded in base64.
+     * @returns A Promise which resolves with {width, height} on success,
+     *   otherwise an error is thrown.
+     */
+    getImageResolution(mediaType, content) {
+        return new Promise((resolve, reject) => {
+            const image = new Image();
+            const eventListeners = new EventListenerCollection();
+            const cleanup = () => {
+                image.removeAttribute('src');
+                URL.revokeObjectURL(url);
+                eventListeners.removeAllEventListeners();
+            };
+            eventListeners.addEventListener(image, 'load', () => {
+                const {naturalWidth: width, naturalHeight: height} = image;
+                cleanup();
+                resolve({width, height});
+            }, false);
+            eventListeners.addEventListener(image, 'error', () => {
+                cleanup();
+                reject(new Error('Image failed to load'));
+            }, false);
+            const blob = MediaUtil.createBlobFromBase64Content(content, mediaType);
+            const url = URL.createObjectURL(blob);
+            image.src = url;
+        });
+    }
+}
diff --git a/ext/js/language/dictionary-importer.js b/ext/js/language/dictionary-importer.js
index 27b3c44e..b931c929 100644
--- a/ext/js/language/dictionary-importer.js
+++ b/ext/js/language/dictionary-importer.js
@@ -22,11 +22,12 @@
  */
 
 class DictionaryImporter {
-    constructor() {
+    constructor(mediaLoader) {
+        this._mediaLoader = mediaLoader;
         this._schemas = new Map();
     }
 
-    async importDictionary(dictionaryDatabase, archiveSource, details, onProgress) {
+    async importDictionary(dictionaryDatabase, archiveContent, details, onProgress) {
         if (!dictionaryDatabase) {
             throw new Error('Invalid database');
         }
@@ -37,7 +38,7 @@ class DictionaryImporter {
         const hasOnProgress = (typeof onProgress === 'function');
 
         // Read archive
-        const archive = await JSZip.loadAsync(archiveSource);
+        const archive = await JSZip.loadAsync(archiveContent);
 
         // Read and validate index
         const indexFileName = 'index.json';
@@ -469,7 +470,7 @@ class DictionaryImporter {
         let width;
         let height;
         try {
-            ({width, height} = await this._getImageResolution(mediaType, content));
+            ({width, height} = await this._mediaLoader.getImageResolution(mediaType, content));
         } catch (e) {
             throw createError('Could not load image');
         }
@@ -502,36 +503,4 @@ class DictionaryImporter {
         }
         return await response.json();
     }
-
-    /**
-     * Attempts to load an image using a base64 encoded content and a media type
-     * and returns its resolution.
-     * @param mediaType The media type for the image content.
-     * @param content The binary content for the image, encoded in base64.
-     * @returns A Promise which resolves with {width, height} on success,
-     *   otherwise an error is thrown.
-     */
-    _getImageResolution(mediaType, content) {
-        return new Promise((resolve, reject) => {
-            const image = new Image();
-            const eventListeners = new EventListenerCollection();
-            const cleanup = () => {
-                image.removeAttribute('src');
-                URL.revokeObjectURL(url);
-                eventListeners.removeAllEventListeners();
-            };
-            eventListeners.addEventListener(image, 'load', () => {
-                const {naturalWidth: width, naturalHeight: height} = image;
-                cleanup();
-                resolve({width, height});
-            }, false);
-            eventListeners.addEventListener(image, 'error', () => {
-                cleanup();
-                reject(new Error('Image failed to load'));
-            }, false);
-            const blob = MediaUtil.createBlobFromBase64Content(content, mediaType);
-            const url = URL.createObjectURL(blob);
-            image.src = url;
-        });
-    }
 }