ite the data to
*
* @return string The minified data
*/
public function minify($path = null)
{
$content = $this->execute($path);
// save to path
if ($path !== null) {
$this->save($content, $path);
}
return $content;
}
/**
* Minify & gzip the data & (optionally) saves it to a file.
*
* @param string[optional] $path Path to write the data to
* @param int[optional] $level Compression level, from 0 to 9
*
* @return string The minified & gzipped data
*/
public function gzip($path = null, $level = 9)
{
$content = $this->execute($path);
$content = gzencode($content, $level, FORCE_GZIP);
// save to path
if ($path !== null) {
$this->save($content, $path);
}
return $content;
}
/**
* Minify the data & write it to a CacheItemInterface object.
*
* @param CacheItemInterface $item Cache item to write the data to
*
* @return CacheItemInterface Cache item with the minifier data
*/
public function cache(CacheItemInterface $item)
{
$content = $this->execute();
$item->set($content);
return $item;
}
/**
* Minify the data.
*
* @param string[optional] $path Path to write the data to
*
* @return string The minified data
*/
abstract public function execute($path = null);
/**
* Load data.
*
* @param string $data Either a path to a file or the content itself
*
* @return string
*/
protected function load($data)
{
// check if the data is a file
if ($this->canImportFile($data)) {
$data = file_get_contents($data);
// strip BOM, if any
if (substr($data, 0, 3) == "\xef\xbb\xbf") {
$data = substr($data, 3);
}
}
return $data;
}
/**
* Save to file.
*
* @param string $content The minified data
* @param string $path The path to save the minified data to
*
* @throws IOException
*/
protected function save($content, $path)
{
$handler = $this->openFileForWriting($path);
$this->writeToFile($handler, $content);
@fclose($handler);
}
/**
* Register a pattern to execute against the source content.
*
* If $replacement is a string, it must be plain text. Placeholders like $1 or \2 don't work.
* If you need that functionality, use a callback instead.
*
* @param string $pattern PCRE pattern
* @param string|callable $replacement Replacement value for matched pattern
*/
protected function registerPattern($pattern, $replacement = '')
{
// study the pattern, we'll execute it more than once
$pattern .= 'S';
$this->patterns[] = array($pattern, $replacement);
}
/**
* Both JS and CSS use the same form of multi-line comment, so putting the common code here.
*/
protected function stripMultilineComments()
{
// First extract comments we want to keep, so they can be restored later
// PHP only supports $this inside anonymous functions since 5.4
$minifier = $this;
$callback = function ($match) use ($minifier) {
$count = count($minifier->extracted);
$placeholder = '/*' . $count . '*/';
$minifier->extracted[$placeholder] = $match[0];
return $placeholder;
};
$this->registerPattern('/
# optional newline
\n?
# start comment
\/\*
# comment content
(?:
# either starts with an !
!
|
# or, after some number of characters which do not end the comment
(?:(?!\*\/).)*?
# there is either a @license or @preserve tag
@(?:license|preserve)
)
# then match to the end of the comment
.*?\*\/\n?
/ixs', $callback);
// Then strip all other comments
$this->registerPattern('/\/\*.*?\*\//s', '');
}
/**
* We can't "just" run some regular expressions against JavaScript: it's a
* complex language. E.g. having an occurrence of // xyz would be a comment,
* unless it's used within a string. Of you could have something that looks
* like a 'string', but inside a comment.
* The only way to accurately replace these pieces is to traverse the JS one
* character at a time and try to find whatever starts first.
*
* @param string $content The content to replace patterns in
*
* @return string The (manipulated) content
*/
protected function replace($content)
{
$contentLength = strlen($content);
$output = '';
$processedOffset = 0;
$positions = array_fill(0, count($this->patterns), -1);
$matches = array();
while ($processedOffset < $contentLength) {
// find first match for all patterns
foreach ($this->patterns as $i => $pattern) {
list($pattern, $replacement) = $pattern;
// we can safely ignore patterns for positions we've unset earlier,
// because we know these won't show up anymore
if (array_key_exists($i, $positions) == false) {
continue;
}
// no need to re-run matches that are still in the part of the
// content that hasn't been processed
if ($positions[$i] >= $processedOffset) {
continue;
}
$match = null;
if (preg_match($pattern, $content, $match, PREG_OFFSET_CAPTURE, $processedOffset)) {
$matches[$i] = $match;
// we'll store the match position as well; that way, we
// don't have to redo all preg_matches after changing only
// the first (we'll still know where those others are)
$positions[$i] = $match[0][1];
} else {
// if the pattern couldn't be matched, there's no point in
// executing it again in later runs on this same content;
// ignore this one until we reach end of content
unset($matches[$i], $positions[$i]);
}
}
// no more matches to find: everything's been processed, break out
if (!$matches) {
// output the remaining content
$output .= substr($content, $processedOffset);
break;
}
// see which of the patterns actually found the first thing (we'll
// only want to execute that one, since we're unsure if what the
// other found was not inside what the first found)
$matchOffset = min($positions);
$firstPattern = array_search($matchOffset, $positions);
$match = $matches[$firstPattern];
// execute the pattern that matches earliest in the content string
list(, $replacement) = $this->patterns[$firstPattern];
// add the part of the input between $processedOffset and the first match;
// that content wasn't matched by anything
$output .= substr($content, $processedOffset, $matchOffset - $processedOffset);
// add the replacement for the match
$output .= $this->executeReplacement($replacement, $match);
// advance $processedOffset past the match
$processedOffset = $matchOffset + strlen($match[0][0]);
}
return $output;
}
/**
* If $replacement is a callback, execute it, passing in the match data.
* If it's a string, just pass it through.
*
* @param string|callable $replacement Replacement value
* @param array $match Match data, in PREG_OFFSET_CAPTURE form
*
* @return string
*/
protected function executeReplacement($replacement, $match)
{
if (!is_callable($replacement)) {
return $replacement;
}
// convert $match from the PREG_OFFSET_CAPTURE form to the form the callback expects
foreach ($match as &$matchItem) {
$matchItem = $matchItem[0];
}
return $replacement($match);
}
/**
* Strings are a pattern we need to match, in order to ignore potential
* code-like content inside them, but we just want all of the string
* content to remain untouched.
*
* This method will replace all string content with simple STRING#
* placeholder text, so we've rid all strings from characters that may be
* misinterpreted. Original string content will be saved in $this->extracted
* and after doing all other minifying, we can restore the original content
* via restoreStrings().
*
* @param string[optional] $chars
* @param string[optional] $placeholderPrefix
*/
protected function extractStrings($chars = '\'"', $placeholderPrefix = '')
{
// PHP only supports $this inside anonymous functions since 5.4
$minifier = $this;
$callback = function ($match) use ($minifier, $placeholderPrefix) {
// check the second index here, because the first always contains a quote
if ($match[2] === '') {
/*
* Empty strings need no placeholder; they can't be confused for
* anything else anyway.
* But we still needed to match them, for the extraction routine
* to skip over this particular string.
*/
return $match[0];
}
$count = count($minifier->extracted);
$placeholder = $match[1] . $placeholderPrefix . $count . $match[1];
$minifier->extracted[$placeholder] = $match[1] . $match[2] . $match[1];
return $placeholder;
};
/*
* The \\ messiness explained:
* * Don't count ' or " as end-of-string if it's escaped (has backslash
* in front of it)
* * Unless... that backslash itself is escaped (another leading slash),
* in which case it's no longer escaping the ' or "
* * So there can be either no backslash, or an even number
* * multiply all of that times 4, to account for the escaping that has
* to be done to pass the backslash into the PHP string without it being
* considered as escape-char (times 2) and to get it in the regex,
* escaped (times 2)
*/
$this->registerPattern('/([' . $chars . '])(.*?(?extracted.
*
* @param string $content
*
* @return string
*/
protected function restoreExtractedData($content)
{
if (!$this->extracted) {
// nothing was extracted, nothing to restore
return $content;
}
$content = strtr($content, $this->extracted);
$this->extracted = array();
return $content;
}
/**
* Check if the path is a regular file and can be read.
*
* @param string $path
*
* @return bool
*/
protected function canImportFile($path)
{
$parsed = parse_url($path);
if (
// file is elsewhere
isset($parsed['host'])
// file responds to queries (may change, or need to bypass cache)
|| isset($parsed['query'])
) {
return false;
}
try {
return strlen($path) < PHP_MAXPATHLEN && @is_file($path) && is_readable($path);
}
// catch openbasedir exceptions which are not caught by @ on is_file()
catch (\Exception $e) {
return false;
}
}
/**
* Attempts to open file specified by $path for writing.
*
* @param string $path The path to the file
*
* @return resource Specifier for the target file
*
* @throws IOException
*/
protected function openFileForWriting($path)
{
if ($path === '' || ($handler = @fopen($path, 'w')) === false) {
throw new IOException('The file "' . $path . '" could not be opened for writing. Check if PHP has enough permissions.');
}
return $handler;
}
/**
* Attempts to write $content to the file specified by $handler. $path is used for printing exceptions.
*
* @param resource $handler The resource to write to
* @param string $content The content to write
* @param string $path The path to the file (for exception printing only)
*
* @throws IOException
*/
protected function writeToFile($handler, $content, $path = '')
{
if (
!is_resource($handler)
|| ($result = @fwrite($handler, $content)) === false
|| ($result < strlen($content))
) {
throw new IOException('The file "' . $path . '" could not be written to. Check your disk space and file permissions.');
}
}
protected static function str_replace_first($search, $replace, $subject)
{
$pos = strpos($subject, $search);
if ($pos !== false) {
return substr_replace($subject, $replace, $pos, strlen($search));
}
return $subject;
}
}
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