<?php
/**
* This file is part of phpDocumentor.
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*
* @copyright 2010-2015 Mike van Riel<mike@phpdoc.org>
* @license http://www.opensource.org/licenses/mit-license.php MIT
* @link http://phpdoc.org
*/
namespace phpDocumentor\Reflection\DocBlock;
use phpDocumentor\Reflection\Types\Context as TypeContext;
/**
* Creates a new Description object given a body of text.
*
* Descriptions in phpDocumentor are somewhat complex entities as they can contain one or more tags inside their
* body that can be replaced with a readable output. The replacing is done by passing a Formatter object to the
* Description object's `render` method.
*
* In addition to the above does a Description support two types of escape sequences:
*
* 1. `{@}` to escape the `@` character to prevent it from being interpreted as part of a tag, i.e. `{{@}link}`
* 2. `{}` to escape the `}` character, this can be used if you want to use the `}` character in the description
* of an inline tag.
*
* If a body consists of multiple lines then this factory will also remove any superfluous whitespace at the beginning
* of each line while maintaining any indentation that is used. This will prevent formatting parsers from tripping
* over unexpected spaces as can be observed with tag descriptions.
*/
class DescriptionFactory
{
/** @var TagFactory */
private $tagFactory;
/**
* Initializes this factory with the means to construct (inline) tags.
*
* @param TagFactory $tagFactory
*/
public function __construct(TagFactory $tagFactory)
{
$this->tagFactory = $tagFactory;
}
/**
* Returns the parsed text of this description.
*
* @param string $contents
* @param TypeContext $context
*
* @return Description
*/
public function create($contents, TypeContext $context = null)
{
list($text, $tags) = $this->parse($this->lex($contents), $context);
return new Description($text, $tags);
}
/**
* Strips the contents from superfluous whitespace and splits the description into a series of tokens.
*
* @param string $contents
*
* @return string[] A series of tokens of which the description text is composed.
*/
private function lex($contents)
{
$contents = $this->removeSuperfluousStartingWhitespace($contents);
// performance optimalization; if there is no inline tag, don't bother splitting it up.
if (strpos($contents, '{@') === false) {
return [$contents];
}
return preg_split(
'/\{
# "{@}" is not a valid inline tag. This ensures that we do not treat it as one, but treat it literally.
(?!@\})
# We want to capture the whole tag line, but without the inline tag delimiters.
(\@
# Match everything up to the next delimiter.
[^{}]*
# Nested inline tag content should not be captured, or it will appear in the result separately.
(?:
# Match nested inline tags.
(?:
# Because we did not catch the tag delimiters earlier, we must be explicit with them here.
# Notice that this also matches "{}", as a way to later introduce it as an escape sequence.
\{(?1)?\}
|
# Make sure we match hanging "{".
\{
)
# Match content after the nested inline tag.
[^{}]*
)* # If there are more inline tags, match them as well. We use "*" since there may not be any
# nested inline tags.
)
\}/Sux',
$contents,
null,
PREG_SPLIT_DELIM_CAPTURE
);
}
/**
* Parses the stream of tokens in to a new set of tokens containing Tags.
*
* @param string[] $tokens
* @param TypeContext $context
*
* @return string[]|Tag[]
*/
private function parse($tokens, TypeContext $context)
{
$count = count($tokens);
$tagCount = 0;
$tags = [];
for ($i = 1; $i < $count; $i += 2) {
$tags[] = $this->tagFactory->create($tokens[$i], $context);
$tokens[$i] = '%' . ++$tagCount . '$s';
}
//In order to allow "literal" inline tags, the otherwise invalid
//sequence "{@}" is changed to "@", and "{}" is changed to "}".
//"%" is escaped to "%%" because of vsprintf.
//See unit tests for examples.
for ($i = 0; $i < $count; $i += 2) {
$tokens[$i] = str_replace(['{@}', '{}', '%'], ['@', '}', '%%'], $tokens[$i]);
}
return [implode('', $tokens), $tags];
}
/**
* Removes the superfluous from a multi-line description.
*
* When a description has more than one line then it can happen that the second and subsequent lines have an
* additional indentation. This is commonly in use with tags like this:
*
* {@}since 1.1.0 This is an example
* description where we have an
* indentation in the second and
* subsequent lines.
*
* If we do not normalize the indentation then we have superfluous whitespace on the second and subsequent
* lines and this may cause rendering issues when, for example, using a Markdown converter.
*
* @param string $contents
*
* @return string
*/
private function removeSuperfluousStartingWhitespace($contents)
{
$lines = explode("\n", $contents);
// if there is only one line then we don't have lines with superfluous whitespace and
// can use the contents as-is
if (count($lines) <= 1) {
return $contents;
}
// determine how many whitespace characters need to be stripped
$startingSpaceCount = 9999999;
for ($i = 1; $i < count($lines); $i++) {
// lines with a no length do not count as they are not indented at all
if (strlen(trim($lines[$i])) === 0) {
continue;
}
// determine the number of prefixing spaces by checking the difference in line length before and after
// an ltrim
$startingSpaceCount = min($startingSpaceCount, strlen($lines[$i]) - strlen(ltrim($lines[$i])));
}
// strip the number of spaces from each line
if ($startingSpaceCount > 0) {
for ($i = 1; $i < count($lines); $i++) {
$lines[$i] = substr($lines[$i], $startingSpaceCount);
}
}
return implode("\n", $lines);
}
}