DOMHelpers is a collection of functions used by the DOMAgent exports eachNode(src, callback)
Extract tag attributes from the given source of a single tag
function _extractAttributes(content) {
// remove the node name and the closing bracket and optional slash
content = content.replace(/^<\S+\s*/, "");
content = content.replace(/\s*\/?>$/, "");
if (content.length === 0) {
return;
}
// go through the items and identify key value pairs split by =
var index, key, value;
var attributes = {};
_findEach(content, [/\s/, 1], true, undefined, function each(item) {
index = item.search("=");
if (index < 0) {
return;
}
// get the key
key = item.substr(0, index).trim();
if (key.length === 0) {
return;
}
// get the value
value = item.substr(index + 1).trim();
value = _removeQuotes(value);
attributes[key] = value;
});
return attributes;
}Find the next match using several constraints
function _find(src, match, skip, quotes, comments) {
if (typeof match === "string") {
match = [match, match.length];
}
if (skip === undefined) {
skip = 0;
}
var i, activeQuote, isComment = false;
for (i = skip; i < src.length; i++) {
if (quotes && _isQuote(src[i], src[i - 1], activeQuote)) {
// starting quote
activeQuote = activeQuote ? undefined : src[i];
} else if (!activeQuote) {
if (comments && !isComment && src.substr(i, comments[0].length) === comments[0]) {
// opening comment
isComment = true;
i += comments[0].length - 1;
} else if (isComment) {
// we are commented
if (src.substr(i, comments[1].length) === comments[1]) {
isComment = false;
i += comments[1].length - 1;
}
} else if (src.substr(i, match[1]).search(match[0]) === 0) {
// match
return i;
}
}
}
return -1;
}Callback iterator using _find
function _findEach(src, match, quotes, comments, callback) {
var from = 0;
var to;
while (from < src.length) {
to = _find(src, match, from, quotes, comments);
if (to < 0) {
to = src.length;
}
callback(src.substr(from, to - from));
from = to + 1;
}
}Find the next tag
function _findTag(src, skip) {
var from, to, inc;
from = _find(src, [/<[a-z!\/]/i, 2], skip);
if (from < 0) {
return null;
}
if (src.substr(from, 4) === "<!--") {
// html comments
to = _find(src, "-->", from + 4);
inc = 3;
} else if (src.substr(from, 7).toLowerCase() === "<script") {
// script tag
to = _find(src.toLowerCase(), "</script>", from + 7);
inc = 9;
} else if (src.substr(from, 6).toLowerCase() === "<style") {
// style tag
to = _find(src.toLowerCase(), "</style>", from + 6);
inc = 8;
} else {
to = _find(src, ">", from + 1, true);
inc = 1;
}
if (to < 0) {
return null;
}
return {from: from, length: to + inc - from};
}Test if the given character is a quote character {char} source character {char} escape (previous) character {char} quote character
function _isQuote(c, escape, quote) {
if (escape === "\\") {
return false;
}
if (quote !== undefined) {
return c === quote;
}
return c === "\"" || c === "'";
}Remove quotes from the string and adjust escaped quotes
function _removeQuotes(src) {
if (_isQuote(src[0]) && src[src.length - 1] === src[0]) {
var q = src[0];
src = src.substr(1, src.length - 2);
src = src.replace("\\" + q, q);
}
return src;
}Extract the node payload
function extractPayload(content) {
var payload = {};
if (content[0] !== "<") {
// text
payload.nodeType = 3;
payload.nodeValue = content;
} else if (content.substr(0, 4) === "<!--") {
// comment
payload.nodeType = 8;
payload.nodeValue = content.substr(4, content.length - 7);
} else if (content[1] === "!") {
// doctype
payload.nodeType = 10;
} else {
// regular element
payload.nodeType = 1;
payload.nodeName = /^<([^>\s]+)/.exec(content)[1].toUpperCase();
payload.attributes = _extractAttributes(content);
// closing node (/ at the beginning)
if (payload.nodeName[0] === "/") {
payload.nodeName = payload.nodeName.substr(1);
payload.closing = true;
}
// closed node (/ at the end)
if (content[content.length - 2] === "/") {
payload.closed = true;
}
// Special handling for script/style tag since we've already collected
// everything up to the end tag.
if (payload.nodeName === "SCRIPT" || payload.nodeName === "STYLE") {
payload.closed = true;
}
}
return payload;
}