From 8a8940e9c22be504e6ebc1f57272b3f339d634a6 Mon Sep 17 00:00:00 2001
From: Abe Jellinek <jellinek@berkeley.edu>
Date: Wed, 1 May 2024 10:07:32 -0400
Subject: [PATCH] EPUB: Show error when EPUB appears to be encrypted

And update .error-bar appearance.
---
 src/common/reader.js                          |  7 ++++++-
 src/common/stylesheets/components/_other.scss |  6 ++++--
 src/dom/common/dom-view.tsx                   |  1 +
 src/dom/epub/epub-view.ts                     | 16 ++++++++++++++++
 src/dom/epub/section-view.ts                  |  3 +++
 src/en-us.strings.js                          |  3 ++-
 6 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/src/common/reader.js b/src/common/reader.js
index 0dc3ce03..0bf75a7d 100644
--- a/src/common/reader.js
+++ b/src/common/reader.js
@@ -741,6 +741,10 @@ class Reader {
 			this._onSetZoom(iframe, zoom);
 		});
 
+		let onEPUBEncrypted = () => {
+			this.setErrorMessage(this._getString('pdfReader.epubEncrypted'));
+		};
+
 		let data;
 		if (this._type === 'pdf') {
 			data = this._data;
@@ -812,7 +816,8 @@ class Reader {
 		} else if (this._type === 'epub') {
 			view = new EPUBView({
 				...common,
-				fontFamily: this._state.fontFamily
+				fontFamily: this._state.fontFamily,
+				onEPUBEncrypted,
 			});
 		} else if (this._type === 'snapshot') {
 			view = new SnapshotView({
diff --git a/src/common/stylesheets/components/_other.scss b/src/common/stylesheets/components/_other.scss
index 47649d4d..7c82dd43 100644
--- a/src/common/stylesheets/components/_other.scss
+++ b/src/common/stylesheets/components/_other.scss
@@ -3,11 +3,13 @@
 	left: 0;
 	right: 0;
 	bottom: 0;
-	height: 25px;
+	font-size: rem(16);
+	height: 2.5em;
 	display: flex;
 	justify-content: center;
 	align-items: center;
-	background-color: #ff7474;
+	background-color: var(--accent-red);
+	color: var(--accent-white);
 	z-index: $z-index-error-bar;
 }
 
diff --git a/src/dom/common/dom-view.tsx b/src/dom/common/dom-view.tsx
index f02ad3b5..3602c37b 100644
--- a/src/dom/common/dom-view.tsx
+++ b/src/dom/common/dom-view.tsx
@@ -1212,6 +1212,7 @@ export type DOMViewOptions<State extends DOMViewState, Data> = {
 	onTabOut: (isShiftTab?: boolean) => void;
 	onKeyUp: (event: KeyboardEvent) => void;
 	onKeyDown: (event: KeyboardEvent) => void;
+	onEPUBEncrypted: () => void;
 	data: Data & {
 		buf?: Uint8Array,
 		url?: string
diff --git a/src/dom/epub/epub-view.ts b/src/dom/epub/epub-view.ts
index 8702f8c5..8201e1e4 100644
--- a/src/dom/epub/epub-view.ts
+++ b/src/dom/epub/epub-view.ts
@@ -154,6 +154,12 @@ class EPUBView extends DOMView<EPUBViewState, EPUBViewData> {
 		let styleScoper = new StyleScoper(this._iframeDocument);
 		await Promise.all(this.book.spine.spineItems.map(section => this._displaySection(section, styleScoper)));
 
+		if (this._sectionViews.some(view => view.error) && await this._isEncrypted()) {
+			this._options.onEPUBEncrypted();
+			this._sectionsContainer.remove();
+			return;
+		}
+
 		if (this._options.fontFamily) {
 			this._iframeDocument.documentElement.style.setProperty('--content-font-family', this._options.fontFamily);
 		}
@@ -195,6 +201,16 @@ class EPUBView extends DOMView<EPUBViewState, EPUBViewData> {
 		this.book.archive.zip = null;
 	}
 
+	private async _isEncrypted() {
+		try {
+			let xml = await this.book.archive.request('/META-INF/encryption.xml', 'text') as string;
+			return xml.includes('<EncryptedData');
+		}
+		catch (e) {
+			return false;
+		}
+	}
+
 	private async _displaySection(section: Section, styleScoper: StyleScoper) {
 		let sectionView = new SectionView({
 			section,
diff --git a/src/dom/epub/section-view.ts b/src/dom/epub/section-view.ts
index 99e2b792..689c0129 100644
--- a/src/dom/epub/section-view.ts
+++ b/src/dom/epub/section-view.ts
@@ -18,6 +18,8 @@ class SectionView {
 
 	body!: HTMLElement;
 
+	error = false;
+
 	private readonly _window: Window & typeof globalThis;
 
 	private readonly _document: Document;
@@ -100,6 +102,7 @@ class SectionView {
 		errorDiv.append(`[Section ${this.section.index}: ${message}]`);
 		this.container.replaceChildren(errorDiv);
 		this.body = errorDiv;
+		this.error = true;
 	}
 
 	/**
diff --git a/src/en-us.strings.js b/src/en-us.strings.js
index 8a85a0cd..7de87d65 100644
--- a/src/en-us.strings.js
+++ b/src/en-us.strings.js
@@ -148,5 +148,6 @@ export default {
 	'pdfReader.preparingDocumentForPrinting': 'Preparing document for printing…',
 	'pdfReader.phraseNotFound': 'Phrase not found',
 	'pdfReader.selectedPages': '{count, plural, one {# page} other {# pages}} selected',
-	'pdfReader.pageOptions': 'Page Options'
+	'pdfReader.pageOptions': 'Page Options',
+	'pdfReader.epubEncrypted': 'This ebook appears to be encrypted and cannot be opened.'
 };