<?php
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* @package log4php
*/
/**
* Most of the work of the {@link LoggerPatternLayout} class
* is delegated to the {@link LoggerPatternParser} class.
*
* <p>It is this class that parses conversion patterns and creates
* a chained list of {@link LoggerPatternConverter} converters.</p>
*
* @version $Revision: 1395467 $
* @package log4php
* @subpackage helpers
*
* @since 0.3
*/
class LoggerPatternParser {
/** Escape character for conversion words in the conversion pattern. */
const ESCAPE_CHAR = '%';
/** Maps conversion words to relevant converters. */
private $converterMap;
/** Conversion pattern used in layout. */
private $pattern;
/** Regex pattern used for parsing the conversion pattern. */
private $regex;
/**
* First converter in the chain.
* @var LoggerPatternConverter
*/
private $head;
/** Last converter in the chain. */
private $tail;
public function __construct($pattern, $converterMap) {
$this->pattern = $pattern;
$this->converterMap = $converterMap;
// Construct the regex pattern
$this->regex =
'/' . // Starting regex pattern delimiter
self::ESCAPE_CHAR . // Character which marks the start of the conversion pattern
'(?P<modifiers>[0-9.-]*)' . // Format modifiers (optional)
'(?P<word>[a-zA-Z]+)' . // The conversion word
'(?P<option>{[^}]*})?' . // Conversion option in braces (optional)
'/'; // Ending regex pattern delimiter
}
/**
* Parses the conversion pattern string, converts it to a chain of pattern
* converters and returns the first converter in the chain.
*
* @return LoggerPatternConverter
*/
public function parse() {
// Skip parsing if the pattern is empty
if (empty($this->pattern)) {
$this->addLiteral('');
return $this->head;
}
// Find all conversion words in the conversion pattern
$count = preg_match_all($this->regex, $this->pattern, $matches, PREG_OFFSET_CAPTURE);
if ($count === false) {
$error = error_get_last();
throw new LoggerException("Failed parsing layotut pattern: {$error['message']}");
}
$prevEnd = 0;
foreach ($matches[0] as $key => $item) {
// Locate where the conversion command starts and ends
$length = strlen($item[0]);
$start = $item[1];
$end = $item[1] + $length;
// Find any literal expressions between matched commands
if ($start > $prevEnd) {
$literal = substr($this->pattern, $prevEnd, $start - $prevEnd);
$this->addLiteral($literal);
}
// Extract the data from the matched command
$word = !empty($matches['word'][$key]) ? $matches['word'][$key][0] : null;
$modifiers = !empty($matches['modifiers'][$key]) ? $matches['modifiers'][$key][0] : null;
$option = !empty($matches['option'][$key]) ? $matches['option'][$key][0] : null;
// Create a converter and add it to the chain
$this->addConverter($word, $modifiers, $option);
$prevEnd = $end;
}
// Add any trailing literals
if ($end < strlen($this->pattern)) {
$literal = substr($this->pattern, $end);
$this->addLiteral($literal);
}
return $this->head;
}
/**
* Adds a literal converter to the converter chain.
* @param string $string The string for the literal converter.
*/
private function addLiteral($string) {
$converter = new LoggerPatternConverterLiteral($string);
$this->addToChain($converter);
}
/**
* Adds a non-literal converter to the converter chain.
*
* @param string $word The conversion word, used to determine which
* converter will be used.
* @param string $modifiers Formatting modifiers.
* @param string $option Option to pass to the converter.
*/
private function addConverter($word, $modifiers, $option) {
$formattingInfo = $this->parseModifiers($modifiers);
$option = trim($option, "{} ");
if (isset($this->converterMap[$word])) {
$converter = $this->getConverter($word, $formattingInfo, $option);
$this->addToChain($converter);
} else {
trigger_error("log4php: Invalid keyword '%$word' in converison pattern. Ignoring keyword.", E_USER_WARNING);
}
}
/**
* Determines which converter to use based on the conversion word. Creates
* an instance of the converter using the provided formatting info and
* option and returns it.
*
* @param string $word The conversion word.
* @param LoggerFormattingInfo $info Formatting info.
* @param string $option Converter option.
*
* @throws LoggerException
*
* @return LoggerPatternConverter
*/
private function getConverter($word, $info, $option) {
if (!isset($this->converterMap[$word])) {
throw new LoggerException("Invalid keyword '%$word' in converison pattern. Ignoring keyword.");
}
$converterClass = $this->converterMap[$word];
if (!class_exists($converterClass)) {
throw new LoggerException("Class '$converterClass' does not exist.");
}
$converter = new $converterClass($info, $option);
if (!($converter instanceof LoggerPatternConverter)) {
throw new LoggerException("Class '$converterClass' is not an instance of LoggerPatternConverter.");
}
return $converter;
}
/** Adds a converter to the chain and updates $head and $tail pointers. */
private function addToChain(LoggerPatternConverter $converter) {
if (!isset($this->head)) {
$this->head = $converter;
$this->tail = $this->head;
} else {
$this->tail->next = $converter;
$this->tail = $this->tail->next;
}
}
/**
* Parses the formatting modifiers and produces the corresponding
* LoggerFormattingInfo object.
*
* @param string $modifier
* @return LoggerFormattingInfo
* @throws LoggerException
*/
private function parseModifiers($modifiers) {
$info = new LoggerFormattingInfo();
// If no modifiers are given, return default values
if (empty($modifiers)) {
return $info;
}
// Validate
$pattern = '/^(-?[0-9]+)?\.?-?[0-9]+$/';
if (!preg_match($pattern, $modifiers)) {
trigger_error("log4php: Invalid modifier in conversion pattern: [$modifiers]. Ignoring modifier.", E_USER_WARNING);
return $info;
}
$parts = explode('.', $modifiers);
if (!empty($parts[0])) {
$minPart = (integer)$parts[0];
$info->min = abs($minPart);
$info->padLeft = ($minPart > 0);
}
if (!empty($parts[1])) {
$maxPart = (integer)$parts[1];
$info->max = abs($maxPart);
$info->trimLeft = ($maxPart < 0);
}
return $info;
}
}