DOMParser replacement (#561)

* Add script to build library files

* Add built parse5 library

* Add new SimpleDOMParser which uses parse5

* Update license info

* Update MV3 build to use the new SimpleDOMParser

* Update file exclusions

* Hide/clarify license info for MV2 builds

3 files changed, 121 insertions, 3 deletions

diff --git a/ext/bg/js/audio-downloader.js b/ext/bg/js/audio-downloader.js
index 839eab7b..d1c4a02e 100644
--- a/ext/bg/js/audio-downloader.js
+++ b/ext/bg/js/audio-downloader.js
@@ -17,6 +17,7 @@
 
 /* global
  * NativeSimpleDOMParser
+ * SimpleDOMParser
  */
 
 class AudioDownloader {
@@ -239,8 +240,10 @@ class AudioDownloader {
     }
 
     _createSimpleDOMParser(content) {
-        if (NativeSimpleDOMParser.isSupported()) {
+        if (typeof NativeSimpleDOMParser !== 'undefined' && NativeSimpleDOMParser.isSupported()) {
             return new NativeSimpleDOMParser(content);
+        } else if (typeof SimpleDOMParser !== 'undefined' && SimpleDOMParser.isSupported()) {
+            return new SimpleDOMParser(content);
         } else {
             throw new Error('DOM parsing not supported');
         }
diff --git a/ext/bg/js/native-simple-dom-parser.js b/ext/bg/js/native-simple-dom-parser.js
index c1752bc4..4e0d89ea 100644
--- a/ext/bg/js/native-simple-dom-parser.js
+++ b/ext/bg/js/native-simple-dom-parser.js
@@ -17,8 +17,6 @@
 
 class NativeSimpleDOMParser {
     constructor(content) {
-        // TODO : Remove
-        // eslint-disable-next-line no-undef
         this._document = new DOMParser().parseFromString(content, 'text/html');
     }
 
diff --git a/ext/bg/js/simple-dom-parser.js b/ext/bg/js/simple-dom-parser.js
new file mode 100644
index 00000000..391ad3d3
--- /dev/null
+++ b/ext/bg/js/simple-dom-parser.js
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2020  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/>.
+ */
+
+/* globals
+ * parse5
+ */
+
+class SimpleDOMParser {
+    constructor(content) {
+        this._document = parse5.parse(content);
+    }
+
+    getElementById(id, root=null) {
+        for (const node of this._allNodes(root)) {
+            if (typeof node.tagName === 'string' && this.getAttribute(node, 'id') === id) {
+                return node;
+            }
+        }
+        return null;
+    }
+
+    getElementByTagName(tagName, root=null) {
+        for (const node of this._allNodes(root)) {
+            if (node.tagName === tagName) {
+                return node;
+            }
+        }
+        return null;
+    }
+
+    getElementsByTagName(tagName, root=null) {
+        const results = [];
+        for (const node of this._allNodes(root)) {
+            if (node.tagName === tagName) {
+                results.push(node);
+            }
+        }
+        return results;
+    }
+
+    getElementsByClassName(className, root=null) {
+        const results = [];
+        const classNamePattern = new RegExp(`(^|\\s)${escapeRegExp(className)}(\\s|$)`);
+        for (const node of this._allNodes(root)) {
+            if (typeof node.tagName === 'string') {
+                const nodeClassName = this.getAttribute(node, 'class');
+                if (nodeClassName !== null && classNamePattern.test(nodeClassName)) {
+                    results.push(node);
+                }
+            }
+        }
+        return results;
+    }
+
+    getAttribute(element, attribute) {
+        for (const attr of element.attrs) {
+            if (
+                attr.name === attribute &&
+                typeof attr.namespace === 'undefined'
+            ) {
+                return attr.value;
+            }
+        }
+        return null;
+    }
+
+    getTextContent(element) {
+        let source = '';
+        for (const node of this._allNodes(element)) {
+            if (node.nodeName === '#text') {
+                source += node.value;
+            }
+        }
+        return source;
+    }
+
+    static isSupported() {
+        return typeof parse5 !== 'undefined';
+    }
+
+    // Private
+
+    *_allNodes(root) {
+        if (root === null) {
+            root = this._document;
+        }
+
+        // Depth-first pre-order traversal
+        const nodeQueue = [root];
+        while (nodeQueue.length > 0) {
+            const node = nodeQueue.pop();
+
+            yield node;
+
+            const childNodes = node.childNodes;
+            if (typeof childNodes !== 'undefined') {
+                for (let i = childNodes.length - 1; i >= 0; --i) {
+                    nodeQueue.push(childNodes[i]);
+                }
+            }
+        }
+    }
+}