fork from https://github.com/mozilla/pdf.js.git

web/overlay_manager.js

@@ -0,0 +1,97 @@
+/* Copyright 2014 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+class OverlayManager {
+  #overlays = new WeakMap();
+
+  #active = null;
+
+  get active() {
+    return this.#active;
+  }
+
+  /**
+   * @param {HTMLDialogElement} dialog - The overlay's DOM element.
+   * @param {boolean} [canForceClose] - Indicates if opening the overlay closes
+   *                  an active overlay. The default is `false`.
+   * @returns {Promise} A promise that is resolved when the overlay has been
+   *                    registered.
+   */
+  async register(dialog, canForceClose = false) {
+    if (typeof dialog !== "object") {
+      throw new Error("Not enough parameters.");
+    } else if (this.#overlays.has(dialog)) {
+      throw new Error("The overlay is already registered.");
+    }
+    this.#overlays.set(dialog, { canForceClose });
+
+    dialog.addEventListener("cancel", ({ target }) => {
+      if (this.#active === target) {
+        this.#active = null;
+      }
+    });
+  }
+
+  /**
+   * @param {HTMLDialogElement} dialog - The overlay's DOM element.
+   * @returns {Promise} A promise that is resolved when the overlay has been
+   *                    opened.
+   */
+  async open(dialog) {
+    if (!this.#overlays.has(dialog)) {
+      throw new Error("The overlay does not exist.");
+    } else if (this.#active) {
+      if (this.#active === dialog) {
+        throw new Error("The overlay is already active.");
+      } else if (this.#overlays.get(dialog).canForceClose) {
+        await this.close();
+      } else {
+        throw new Error("Another overlay is currently active.");
+      }
+    }
+    this.#active = dialog;
+    dialog.showModal();
+  }
+
+  /**
+   * @param {HTMLDialogElement} dialog - The overlay's DOM element.
+   * @returns {Promise} A promise that is resolved when the overlay has been
+   *                    closed.
+   */
+  async close(dialog = this.#active) {
+    if (!this.#overlays.has(dialog)) {
+      throw new Error("The overlay does not exist.");
+    } else if (!this.#active) {
+      throw new Error("The overlay is currently not active.");
+    } else if (this.#active !== dialog) {
+      throw new Error("Another overlay is currently active.");
+    }
+    dialog.close();
+    this.#active = null;
+  }
+
+  /**
+   * @param {HTMLDialogElement} dialog - The overlay's DOM element.
+   * @returns {Promise} A promise that is resolved when the overlay has been
+   *                    closed.
+   */
+  async closeIfActive(dialog) {
+    if (this.#active === dialog) {
+      await this.close(dialog);
+    }
+  }
+}
+
+export { OverlayManager };