pdf.js/external/builder/builder.js
2016-05-09 18:18:43 -05:00

329 lines
9.6 KiB
JavaScript

/* jshint node:true */
/* globals cp, ls, test */
'use strict';
var fs = require('fs'),
path = require('path'),
vm = require('vm');
/**
* A simple preprocessor that is based on the Firefox preprocessor
* (https://dxr.mozilla.org/mozilla-central/source/build/docs/preprocessor.rst).
* The main difference is that this supports a subset of the commands and it
* supports preprocessor commands in HTML-style comments.
*
* Currently supported commands:
* - if
* - elif
* - else
* - endif
* - include
* - expand
* - error
*
* Every #if must be closed with an #endif. Nested conditions are supported.
*
* Within an #if or #else block, one level of comment tokens is stripped. This
* allows us to write code that can run even without preprocessing. For example:
*
* //#if SOME_RARE_CONDITION
* // // Decrement by one
* // --i;
* //#else
* // // Increment by one.
* ++i;
* //#endif
*/
function preprocess(inFilename, outFilename, defines) {
// TODO make this really read line by line.
var lines = fs.readFileSync(inFilename).toString().split('\n');
var totalLines = lines.length;
var out = '';
var i = 0;
function readLine() {
if (i < totalLines) {
return lines[i++];
}
return null;
}
var writeLine = (typeof outFilename === 'function' ? outFilename :
function(line) {
out += line + '\n';
});
function evaluateCondition(code) {
if (!code || !code.trim()) {
throw new Error('No JavaScript expression given at ' + loc());
}
try {
return vm.runInNewContext(code, defines, {displayErrors: false});
} catch (e) {
throw new Error('Could not evaluate "' + code + '" at ' + loc() + '\n' +
e.name + ': ' + e.message);
}
}
function include(file) {
var realPath = fs.realpathSync(inFilename);
var dir = path.dirname(realPath);
try {
var fullpath;
if (file.indexOf('$ROOT/') === 0) {
fullpath = path.join(__dirname, '../..',
file.substring('$ROOT/'.length));
} else {
fullpath = path.join(dir, file);
}
preprocess(fullpath, writeLine, defines);
} catch (e) {
if (e.code === 'ENOENT') {
throw new Error('Failed to include "' + file + '" at ' + loc());
}
throw e; // Some other error
}
}
function expand(line) {
line = line.replace(/__[\w]+__/g, function(variable) {
variable = variable.substring(2, variable.length - 2);
if (variable in defines) {
return defines[variable];
}
return '';
});
writeLine(line);
}
// not inside if or else (process lines)
var STATE_NONE = 0;
// inside if, condition false (ignore until #else or #endif)
var STATE_IF_FALSE = 1;
// inside else, #if was false, so #else is true (process lines until #endif)
var STATE_ELSE_TRUE = 2;
// inside if, condition true (process lines until #else or #endif)
var STATE_IF_TRUE = 3;
// inside else or elif, #if/#elif was true, so following #else or #elif is
// false (ignore lines until #endif)
var STATE_ELSE_FALSE = 4;
var line;
var state = STATE_NONE;
var stack = [];
var control =
/* jshint -W101 */
/^(?:\/\/|<!--)\s*#(if|elif|else|endif|expand|include|error)\b(?:\s+(.*?)(?:-->)?$)?/;
/* jshint +W101 */
var lineNumber = 0;
var loc = function() {
return fs.realpathSync(inFilename) + ':' + lineNumber;
};
while ((line = readLine()) !== null) {
++lineNumber;
var m = control.exec(line);
if (m) {
switch (m[1]) {
case 'if':
stack.push(state);
state = evaluateCondition(m[2]) ? STATE_IF_TRUE : STATE_IF_FALSE;
break;
case 'elif':
if (state === STATE_IF_TRUE || state === STATE_ELSE_FALSE) {
state = STATE_ELSE_FALSE;
} else if (state === STATE_IF_FALSE) {
state = evaluateCondition(m[2]) ? STATE_IF_TRUE : STATE_IF_FALSE;
} else if (state === STATE_ELSE_TRUE) {
throw new Error('Found #elif after #else at ' + loc());
} else {
throw new Error('Found #elif without matching #if at ' + loc());
}
break;
case 'else':
if (state === STATE_IF_TRUE || state === STATE_ELSE_FALSE) {
state = STATE_ELSE_FALSE;
} else if (state === STATE_IF_FALSE) {
state = STATE_ELSE_TRUE;
} else {
throw new Error('Found #else without matching #if at ' + loc());
}
break;
case 'endif':
if (state === STATE_NONE) {
throw new Error('Found #endif without #if at ' + loc());
}
state = stack.pop();
break;
case 'expand':
if (state !== STATE_IF_FALSE && state !== STATE_ELSE_FALSE) {
expand(m[2]);
}
break;
case 'include':
if (state !== STATE_IF_FALSE && state !== STATE_ELSE_FALSE) {
include(m[2]);
}
break;
case 'error':
if (state !== STATE_IF_FALSE && state !== STATE_ELSE_FALSE) {
throw new Error('Found #error ' + m[2] + ' at ' + loc());
}
break;
}
} else {
if (state === STATE_NONE) {
writeLine(line);
} else if ((state === STATE_IF_TRUE || state === STATE_ELSE_TRUE) &&
stack.indexOf(STATE_IF_FALSE) === -1 &&
stack.indexOf(STATE_ELSE_FALSE) === -1) {
writeLine(line.replace(/^\/\/|^<!--|-->$/g, ' '));
}
}
}
if (state !== STATE_NONE || stack.length !== 0) {
throw new Error('Missing #endif in preprocessor for ' +
fs.realpathSync(inFilename));
}
if (typeof outFilename !== 'function') {
fs.writeFileSync(outFilename, out);
}
}
exports.preprocess = preprocess;
var deprecatedInMozcentral = new RegExp('(^|\\W)(' + [
'-moz-box-sizing',
'-moz-grab',
'-moz-grabbing'
].join('|') + ')');
function preprocessCSS(mode, source, destination) {
function hasPrefixedFirefox(line) {
return (/(^|\W)-(ms|o|webkit)-\w/.test(line));
}
function hasPrefixedMozcentral(line) {
return (/(^|\W)-(ms|o|webkit)-\w/.test(line) ||
deprecatedInMozcentral.test(line));
}
function expandImports(content, baseUrl) {
return content.replace(/^\s*@import\s+url\(([^\)]+)\);\s*$/gm,
function(all, url) {
var file = path.join(path.dirname(baseUrl), url);
var imported = fs.readFileSync(file, 'utf8').toString();
return expandImports(imported, file);
});
}
function removePrefixed(content, hasPrefixedFilter) {
var lines = content.split(/\r?\n/g);
var i = 0;
while (i < lines.length) {
var line = lines[i];
if (!hasPrefixedFilter(line)) {
i++;
continue;
}
if (/\{\s*$/.test(line)) {
var bracketLevel = 1;
var j = i + 1;
while (j < lines.length && bracketLevel > 0) {
var checkBracket = /([{}])\s*$/.exec(lines[j]);
if (checkBracket) {
if (checkBracket[1] === '{') {
bracketLevel++;
} else if (lines[j].indexOf('{') < 0) {
bracketLevel--;
}
}
j++;
}
lines.splice(i, j - i);
} else if (/[};]\s*$/.test(line)) {
lines.splice(i, 1);
} else {
// multiline? skipping until next directive or bracket
do {
lines.splice(i, 1);
} while (i < lines.length &&
!/\}\s*$/.test(lines[i]) &&
lines[i].indexOf(':') < 0);
if (i < lines.length && /\S\s*}\s*$/.test(lines[i])) {
lines[i] = lines[i].substr(lines[i].indexOf('}'));
}
}
// collapse whitespaces
while (lines[i] === '' && lines[i - 1] === '') {
lines.splice(i, 1);
}
}
return lines.join('\n');
}
if (!mode) {
throw new Error('Invalid CSS preprocessor mode');
}
var content = fs.readFileSync(source, 'utf8').toString();
content = expandImports(content, source);
if (mode === 'mozcentral' || mode === 'firefox') {
content = removePrefixed(content, mode === 'mozcentral' ?
hasPrefixedMozcentral : hasPrefixedFirefox);
}
fs.writeFileSync(destination, content);
}
exports.preprocessCSS = preprocessCSS;
/**
* Simplifies common build steps.
* @param {object} setup
* .defines defines for preprocessors
* .copy array of arrays of source and destination pairs of files to copy
* .preprocess array of arrays of source and destination pairs of files
* run through preprocessor.
*/
function build(setup) {
var defines = setup.defines;
setup.copy.forEach(function(option) {
var source = option[0];
var destination = option[1];
cp('-R', source, destination);
});
setup.preprocess.forEach(function(option) {
var sources = option[0];
var destination = option[1];
sources = ls('-R', sources);
sources.forEach(function(source) {
// ??? Warn if the source is wildcard and dest is file?
var destWithFolder = destination;
if (test('-d', destination)) {
destWithFolder += '/' + path.basename(source);
}
preprocess(source, destWithFolder, defines);
});
});
(setup.preprocessCSS || []).forEach(function(option) {
var mode = option[0];
var source = option[1];
var destination = option[2];
preprocessCSS(mode, source, destination);
});
}
exports.build = build;
/**
* Merge two defines arrays. Values in the second param will override values in
* the first.
*/
function merge(defaults, defines) {
var ret = {};
for (var key in defaults) {
ret[key] = defaults[key];
}
for (key in defines) {
ret[key] = defines[key];
}
return ret;
}
exports.merge = merge;