Add AccessibilityController class, which dynamically registers (#2024)

and unregisters the google-docs.js content script

1 files changed, 97 insertions, 0 deletions

diff --git a/ext/js/accessibility/accessibility-controller.js b/ext/js/accessibility/accessibility-controller.js
new file mode 100644
index 00000000..a995d5d0
--- /dev/null
+++ b/ext/js/accessibility/accessibility-controller.js
@@ -0,0 +1,97 @@
+/*
+ * 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/>.
+ */
+
+/**
+ * This class controls the registration of accessibility handlers.
+ */
+class AccessibilityController {
+    /**
+     * Creates a new instance.
+     * @param {ScriptManager} scriptManager An instance of the `ScriptManager` class.
+     */
+    constructor(scriptManager) {
+        this._scriptManager = scriptManager;
+        this._updateGoogleDocsAccessibilityToken = null;
+        this._updateGoogleDocsAccessibilityPromise = null;
+        this._forceGoogleDocsHtmlRenderingAny = false;
+    }
+
+    /**
+     * Updates the accessibility handlers.
+     * @param {object} fullOptions The full options object from the `Backend` instance.
+     *   The value is treated as read-only and is not modified.
+     */
+    async update(fullOptions) {
+        let forceGoogleDocsHtmlRenderingAny = false;
+        for (const {options} of fullOptions.profiles) {
+            if (options.accessibility.forceGoogleDocsHtmlRendering) {
+                forceGoogleDocsHtmlRenderingAny = true;
+                break;
+            }
+        }
+
+        await this._updateGoogleDocsAccessibility(forceGoogleDocsHtmlRenderingAny);
+    }
+
+    // Private
+
+    async _updateGoogleDocsAccessibility(forceGoogleDocsHtmlRenderingAny) {
+        // Reentrant token
+        const token = {};
+        this._updateGoogleDocsAccessibilityToken = token;
+
+        // Wait for previous
+        let promise = this._updateGoogleDocsAccessibilityPromise;
+        if (promise !== null) { await promise; }
+
+        // Reentrant check
+        if (this._updateGoogleDocsAccessibilityToken !== token) { return; }
+
+        // Update
+        promise = this._updateGoogleDocsAccessibilityInner(forceGoogleDocsHtmlRenderingAny);
+        this._updateGoogleDocsAccessibilityPromise = promise;
+        await promise;
+        this._updateGoogleDocsAccessibilityPromise = null;
+    }
+
+    async _updateGoogleDocsAccessibilityInner(forceGoogleDocsHtmlRenderingAny) {
+        if (this._forceGoogleDocsHtmlRenderingAny === forceGoogleDocsHtmlRenderingAny) { return; }
+
+        this._forceGoogleDocsHtmlRenderingAny = forceGoogleDocsHtmlRenderingAny;
+
+        const id = 'googleDocsAccessibility';
+        try {
+            if (forceGoogleDocsHtmlRenderingAny) {
+                if (await this._scriptManager.isContentScriptRegistered(id)) { return; }
+                const details = {
+                    allFrames: true,
+                    matchAboutBlank: true,
+                    matches: ['*://docs.google.com/*'],
+                    urlMatches: '^[^:]*://docs.google.com/[\\w\\W]*$',
+                    runAt: 'document_start',
+                    js: ['js/accessibility/google-docs.js']
+                };
+                await this._scriptManager.registerContentScript(id, details);
+            } else {
+                await this._scriptManager.unregisterContentScript(id);
+            }
+        } catch (e) {
+            log.error(e);
+        }
+    }
+}
+