Files
meteor/packages/templating/html_scanner.js
2012-08-13 10:45:04 -07:00

159 lines
4.9 KiB
JavaScript

var html_scanner = {
// Scan a template file for <head>, <body>, and <template>
// tags and extract their contents.
//
// This is a primitive, regex-based scanner. It scans
// top-level tags, which are allowed to have attributes,
// and ignores top-level HTML comments.
scan: function (contents, source_name) {
var rest = contents;
var index = 0;
var advance = function(amount) {
rest = rest.substring(amount);
index += amount;
};
var parseError = function(msg) {
var lineNumber = contents.substring(0, index).split('\n').length;
var line = contents.split('\n')[lineNumber - 1];
var info = "line "+lineNumber+", file "+source_name + "\n" + line;
return new Error((msg || "Parse error")+" - "+info);
};
var results = html_scanner._initResults();
var rOpenTag = /^((<(template|head|body)\b)|(<!--)|(<!DOCTYPE|{{!)|$)/i;
while (rest) {
// skip whitespace first (for better line numbers)
advance(rest.match(/^\s*/)[0].length);
var match = rOpenTag.exec(rest);
if (! match)
throw parseError(); // unknown text encountered
var matchToken = match[1];
var matchTokenTagName = match[3];
var matchTokenComment = match[4];
var matchTokenUnsupported = match[5];
advance(match.index + match[0].length);
if (! matchToken)
break; // matched $ (end of file)
if (matchTokenComment === '<!--') {
// top-level HTML comment
var commentEnd = /--\s*>/.exec(rest);
if (! commentEnd)
throw parseError("unclosed HTML comment");
advance(commentEnd.index + commentEnd[0].length);
continue;
}
if (matchTokenUnsupported) {
switch (matchTokenUnsupported.toLowerCase()) {
case '<!doctype':
throw parseError(
"Can't set DOCTYPE here. (Meteor sets <!DOCTYPE html> for you)");
case '{{!':
throw new parseError(
"Can't use '{{! }}' outside a template. Use '<!-- -->'.");
}
throw new parseError();
}
// otherwise, a <tag>
var tagName = matchTokenTagName.toLowerCase();
var tagAttribs = {}; // bare name -> value dict
var rTagPart = /^\s*((([a-zA-Z0-9:_-]+)\s*=\s*(["'])(.*?)\4)|(>))/;
var attr;
// read attributes
while ((attr = rTagPart.exec(rest))) {
var attrToken = attr[1];
var attrKey = attr[3];
var attrValue = attr[5];
advance(attr.index + attr[0].length);
if (attrToken === '>')
break;
// XXX we don't HTML unescape the attribute value
// (e.g. to allow "abcd&quot;efg") or protect against
// collisions with methods of tagAttribs (e.g. for
// a property named toString)
attrValue = attrValue.match(/^\s*([\s\S]*?)\s*$/)[1]; // trim
tagAttribs[attrKey] = attrValue;
}
if (! attr) // didn't end on '>'
throw new parseError("Parse error in tag");
// find </tag>
var end = (new RegExp('</'+tagName+'\\s*>', 'i')).exec(rest);
if (! end)
throw new parseError("unclosed <"+tagName+">");
var tagContents = rest.slice(0, end.index);
advance(end.index + end[0].length);
// act on the tag
html_scanner._handleTag(results, tagName, tagAttribs, tagContents,
parseError);
}
return results;
},
_initResults: function() {
var results = {};
results.head = '';
results.body = '';
results.js = '';
return results;
},
_handleTag: function (results, tag, attribs, contents, parseError) {
// trim the tag contents.
// this is a courtesy and is also relied on by some unit tests.
contents = contents.match(/^[ \t\r\n]*([\s\S]*?)[ \t\r\n]*$/)[1];
// do we have 1 or more attribs?
var hasAttribs = false;
for(var k in attribs) {
if (attribs.hasOwnProperty(k)) {
hasAttribs = true;
break;
}
}
if (tag === "head") {
if (hasAttribs)
throw parseError("Attributes on <head> not supported");
results.head += contents;
return;
}
// <body> or <template>
var code = 'Handlebars.json_ast_to_func(' +
JSON.stringify(Handlebars.to_json_ast(contents)) + ')';
if (tag === "template") {
var name = attribs.name;
if (! name)
throw parseError("Template has no 'name' attribute");
results.js += "Meteor._def_template(" + JSON.stringify(name) + ","
+ code + ");\n";
} else {
// <body>
if (hasAttribs)
throw parseError("Attributes on <body> not supported");
results.js += "Meteor.startup(function(){" +
"document.body.appendChild(Spark.render(" +
"Meteor._def_template(null," + code + ")));});";
}
}
};
// If we are running at bundle time, set module.exports.
// For unit testing in server environment, don't.
if (typeof module !== 'undefined')
module.exports = html_scanner;