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node_modules/xss/lib/parser.js

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+/**
+ * Simple HTML Parser
+ *
+ * @author Zongmin Lei<leizongmin@gmail.com>
+ */
+
+var _ = require("./util");
+
+/**
+ * get tag name
+ *
+ * @param {String} html e.g. '<a hef="#">'
+ * @return {String}
+ */
+function getTagName(html) {
+  var i = _.spaceIndex(html);
+  var tagName;
+  if (i === -1) {
+    tagName = html.slice(1, -1);
+  } else {
+    tagName = html.slice(1, i + 1);
+  }
+  tagName = _.trim(tagName).toLowerCase();
+  if (tagName.slice(0, 1) === "/") tagName = tagName.slice(1);
+  if (tagName.slice(-1) === "/") tagName = tagName.slice(0, -1);
+  return tagName;
+}
+
+/**
+ * is close tag?
+ *
+ * @param {String} html 如：'<a hef="#">'
+ * @return {Boolean}
+ */
+function isClosing(html) {
+  return html.slice(0, 2) === "</";
+}
+
+/**
+ * parse input html and returns processed html
+ *
+ * @param {String} html
+ * @param {Function} onTag e.g. function (sourcePosition, position, tag, html, isClosing)
+ * @param {Function} escapeHtml
+ * @return {String}
+ */
+function parseTag(html, onTag, escapeHtml) {
+  "use strict";
+
+  var rethtml = "";
+  var lastPos = 0;
+  var tagStart = false;
+  var quoteStart = false;
+  var currentPos = 0;
+  var len = html.length;
+  var currentTagName = "";
+  var currentHtml = "";
+
+  chariterator: for (currentPos = 0; currentPos < len; currentPos++) {
+    var c = html.charAt(currentPos);
+    if (tagStart === false) {
+      if (c === "<") {
+        tagStart = currentPos;
+        continue;
+      }
+    } else {
+      if (quoteStart === false) {
+        if (c === "<") {
+          rethtml += escapeHtml(html.slice(lastPos, currentPos));
+          tagStart = currentPos;
+          lastPos = currentPos;
+          continue;
+        }
+        if (c === ">" || currentPos === len - 1) {
+          rethtml += escapeHtml(html.slice(lastPos, tagStart));
+          currentHtml = html.slice(tagStart, currentPos + 1);
+          currentTagName = getTagName(currentHtml);
+          rethtml += onTag(
+            tagStart,
+            rethtml.length,
+            currentTagName,
+            currentHtml,
+            isClosing(currentHtml)
+          );
+          lastPos = currentPos + 1;
+          tagStart = false;
+          continue;
+        }
+        if (c === '"' || c === "'") {
+          var i = 1;
+          var ic = html.charAt(currentPos - i);
+
+          while (ic.trim() === "" || ic === "=") {
+            if (ic === "=") {
+              quoteStart = c;
+              continue chariterator;
+            }
+            ic = html.charAt(currentPos - ++i);
+          }
+        }
+      } else {
+        if (c === quoteStart) {
+          quoteStart = false;
+          continue;
+        }
+      }
+    }
+  }
+  if (lastPos < len) {
+    rethtml += escapeHtml(html.substr(lastPos));
+  }
+
+  return rethtml;
+}
+
+var REGEXP_ILLEGAL_ATTR_NAME = /[^a-zA-Z0-9\\_:.-]/gim;
+
+/**
+ * parse input attributes and returns processed attributes
+ *
+ * @param {String} html e.g. `href="#" target="_blank"`
+ * @param {Function} onAttr e.g. `function (name, value)`
+ * @return {String}
+ */
+function parseAttr(html, onAttr) {
+  "use strict";
+
+  var lastPos = 0;
+  var lastMarkPos = 0;
+  var retAttrs = [];
+  var tmpName = false;
+  var len = html.length;
+
+  function addAttr(name, value) {
+    name = _.trim(name);
+    name = name.replace(REGEXP_ILLEGAL_ATTR_NAME, "").toLowerCase();
+    if (name.length < 1) return;
+    var ret = onAttr(name, value || "");
+    if (ret) retAttrs.push(ret);
+  }
+
+  // 逐个分析字符
+  for (var i = 0; i < len; i++) {
+    var c = html.charAt(i);
+    var v, j;
+    if (tmpName === false && c === "=") {
+      tmpName = html.slice(lastPos, i);
+      lastPos = i + 1;
+      lastMarkPos = html.charAt(lastPos) === '"' || html.charAt(lastPos) === "'" ? lastPos : findNextQuotationMark(html, i + 1);
+      continue;
+    }
+    if (tmpName !== false) {
+      if (
+        i === lastMarkPos
+      ) {
+        j = html.indexOf(c, i + 1);
+        if (j === -1) {
+          break;
+        } else {
+          v = _.trim(html.slice(lastMarkPos + 1, j));
+          addAttr(tmpName, v);
+          tmpName = false;
+          i = j;
+          lastPos = i + 1;
+          continue;
+        }
+      }
+    }
+    if (/\s|\n|\t/.test(c)) {
+      html = html.replace(/\s|\n|\t/g, " ");
+      if (tmpName === false) {
+        j = findNextEqual(html, i);
+        if (j === -1) {
+          v = _.trim(html.slice(lastPos, i));
+          addAttr(v);
+          tmpName = false;
+          lastPos = i + 1;
+          continue;
+        } else {
+          i = j - 1;
+          continue;
+        }
+      } else {
+        j = findBeforeEqual(html, i - 1);
+        if (j === -1) {
+          v = _.trim(html.slice(lastPos, i));
+          v = stripQuoteWrap(v);
+          addAttr(tmpName, v);
+          tmpName = false;
+          lastPos = i + 1;
+          continue;
+        } else {
+          continue;
+        }
+      }
+    }
+  }
+
+  if (lastPos < html.length) {
+    if (tmpName === false) {
+      addAttr(html.slice(lastPos));
+    } else {
+      addAttr(tmpName, stripQuoteWrap(_.trim(html.slice(lastPos))));
+    }
+  }
+
+  return _.trim(retAttrs.join(" "));
+}
+
+function findNextEqual(str, i) {
+  for (; i < str.length; i++) {
+    var c = str[i];
+    if (c === " ") continue;
+    if (c === "=") return i;
+    return -1;
+  }
+}
+
+function findNextQuotationMark(str, i) {
+  for (; i < str.length; i++) {
+    var c = str[i];
+    if (c === " ") continue;
+    if (c === "'" || c === '"') return i;
+    return -1;
+  }
+}
+
+function findBeforeEqual(str, i) {
+  for (; i > 0; i--) {
+    var c = str[i];
+    if (c === " ") continue;
+    if (c === "=") return i;
+    return -1;
+  }
+}
+
+function isQuoteWrapString(text) {
+  if (
+    (text[0] === '"' && text[text.length - 1] === '"') ||
+    (text[0] === "'" && text[text.length - 1] === "'")
+  ) {
+    return true;
+  } else {
+    return false;
+  }
+}
+
+function stripQuoteWrap(text) {
+  if (isQuoteWrapString(text)) {
+    return text.substr(1, text.length - 2);
+  } else {
+    return text;
+  }
+}
+
+exports.parseTag = parseTag;
+exports.parseAttr = parseAttr;