diff --git a/plugins/libkolab/libkolab.php b/plugins/libkolab/libkolab.php index c32d65a3..052724c8 100644 --- a/plugins/libkolab/libkolab.php +++ b/plugins/libkolab/libkolab.php @@ -124,4 +124,15 @@ class libkolab extends rcube_plugin return $request; } + + /** + * Wrapper function for generating a html diff using the FineDiff class by Raymond Hill + */ + public static function html_diff($from, $to) + { + include_once __dir__ . '/vendor/finediff.php'; + + $diff = new FineDiff($from, $to, FineDiff::$wordGranularity); + return $diff->renderDiffToHTML(); + } } diff --git a/plugins/libkolab/vendor/finediff.php b/plugins/libkolab/vendor/finediff.php new file mode 100644 index 00000000..b3c416ce --- /dev/null +++ b/plugins/libkolab/vendor/finediff.php @@ -0,0 +1,688 @@ +copy->insert +* command (swap) for when the inserted segment is exactly the same +* as the deleted one, and with only a copy operation in between. +* TODO: How often this case occurs? Is it worth it? Can only +* be done as a postprocessing method (->optimize()?) +*/ +abstract class FineDiffOp { + abstract public function getFromLen(); + abstract public function getToLen(); + abstract public function getOpcode(); + } + +class FineDiffDeleteOp extends FineDiffOp { + public function __construct($len) { + $this->fromLen = $len; + } + public function getFromLen() { + return $this->fromLen; + } + public function getToLen() { + return 0; + } + public function getOpcode() { + if ( $this->fromLen === 1 ) { + return 'd'; + } + return "d{$this->fromLen}"; + } + } + +class FineDiffInsertOp extends FineDiffOp { + public function __construct($text) { + $this->text = $text; + } + public function getFromLen() { + return 0; + } + public function getToLen() { + return strlen($this->text); + } + public function getText() { + return $this->text; + } + public function getOpcode() { + $to_len = strlen($this->text); + if ( $to_len === 1 ) { + return "i:{$this->text}"; + } + return "i{$to_len}:{$this->text}"; + } + } + +class FineDiffReplaceOp extends FineDiffOp { + public function __construct($fromLen, $text) { + $this->fromLen = $fromLen; + $this->text = $text; + } + public function getFromLen() { + return $this->fromLen; + } + public function getToLen() { + return strlen($this->text); + } + public function getText() { + return $this->text; + } + public function getOpcode() { + if ( $this->fromLen === 1 ) { + $del_opcode = 'd'; + } + else { + $del_opcode = "d{$this->fromLen}"; + } + $to_len = strlen($this->text); + if ( $to_len === 1 ) { + return "{$del_opcode}i:{$this->text}"; + } + return "{$del_opcode}i{$to_len}:{$this->text}"; + } + } + +class FineDiffCopyOp extends FineDiffOp { + public function __construct($len) { + $this->len = $len; + } + public function getFromLen() { + return $this->len; + } + public function getToLen() { + return $this->len; + } + public function getOpcode() { + if ( $this->len === 1 ) { + return 'c'; + } + return "c{$this->len}"; + } + public function increase($size) { + return $this->len += $size; + } + } + +/** +* FineDiff ops +* +* Collection of ops +*/ +class FineDiffOps { + public function appendOpcode($opcode, $from, $from_offset, $from_len) { + if ( $opcode === 'c' ) { + $edits[] = new FineDiffCopyOp($from_len); + } + else if ( $opcode === 'd' ) { + $edits[] = new FineDiffDeleteOp($from_len); + } + else /* if ( $opcode === 'i' ) */ { + $edits[] = new FineDiffInsertOp(substr($from, $from_offset, $from_len)); + } + } + public $edits = array(); + } + +/** +* FineDiff class +* +* TODO: Document +* +*/ +class FineDiff { + + /**------------------------------------------------------------------------ + * + * Public section + * + */ + + /** + * Constructor + * ... + * The $granularityStack allows FineDiff to be configurable so that + * a particular stack tailored to the specific content of a document can + * be passed. + */ + public function __construct($from_text = '', $to_text = '', $granularityStack = null) { + // setup stack for generic text documents by default + $this->granularityStack = $granularityStack ? $granularityStack : FineDiff::$characterGranularity; + $this->edits = array(); + $this->from_text = $from_text; + $this->doDiff($from_text, $to_text); + } + + public function getOps() { + return $this->edits; + } + + public function getOpcodes() { + $opcodes = array(); + foreach ( $this->edits as $edit ) { + $opcodes[] = $edit->getOpcode(); + } + return implode('', $opcodes); + } + + public function renderDiffToHTML() { + $in_offset = 0; + $html = ''; + foreach ( $this->edits as $edit ) { + $n = $edit->getFromLen(); + if ( $edit instanceof FineDiffCopyOp ) { + $html .= FineDiff::renderDiffToHTMLFromOpcode('c', $this->from_text, $in_offset, $n); + } + else if ( $edit instanceof FineDiffDeleteOp ) { + $html .= FineDiff::renderDiffToHTMLFromOpcode('d', $this->from_text, $in_offset, $n); + } + else if ( $edit instanceof FineDiffInsertOp ) { + $html .= FineDiff::renderDiffToHTMLFromOpcode('i', $edit->getText(), 0, $edit->getToLen()); + } + else /* if ( $edit instanceof FineDiffReplaceOp ) */ { + $html .= FineDiff::renderDiffToHTMLFromOpcode('d', $this->from_text, $in_offset, $n); + $html .= FineDiff::renderDiffToHTMLFromOpcode('i', $edit->getText(), 0, $edit->getToLen()); + } + $in_offset += $n; + } + return $html; + } + + /**------------------------------------------------------------------------ + * Return an opcodes string describing the diff between a "From" and a + * "To" string + */ + public static function getDiffOpcodes($from, $to, $granularities = null) { + $diff = new FineDiff($from, $to, $granularities); + return $diff->getOpcodes(); + } + + /**------------------------------------------------------------------------ + * Return an iterable collection of diff ops from an opcodes string + */ + public static function getDiffOpsFromOpcodes($opcodes) { + $diffops = new FineDiffOps(); + FineDiff::renderFromOpcodes(null, $opcodes, array($diffops,'appendOpcode')); + return $diffops->edits; + } + + /**------------------------------------------------------------------------ + * Re-create the "To" string from the "From" string and an "Opcodes" string + */ + public static function renderToTextFromOpcodes($from, $opcodes) { + return FineDiff::renderFromOpcodes($from, $opcodes, array('FineDiff','renderToTextFromOpcode')); + } + + /**------------------------------------------------------------------------ + * Render the diff to an HTML string + */ + public static function renderDiffToHTMLFromOpcodes($from, $opcodes) { + return FineDiff::renderFromOpcodes($from, $opcodes, array('FineDiff','renderDiffToHTMLFromOpcode')); + } + + /**------------------------------------------------------------------------ + * Generic opcodes parser, user must supply callback for handling + * single opcode + */ + public static function renderFromOpcodes($from, $opcodes, $callback) { + if ( !is_callable($callback) ) { + return ''; + } + $out = ''; + $opcodes_len = strlen($opcodes); + $from_offset = $opcodes_offset = 0; + while ( $opcodes_offset < $opcodes_len ) { + $opcode = substr($opcodes, $opcodes_offset, 1); + $opcodes_offset++; + $n = intval(substr($opcodes, $opcodes_offset)); + if ( $n ) { + $opcodes_offset += strlen(strval($n)); + } + else { + $n = 1; + } + if ( $opcode === 'c' ) { // copy n characters from source + $out .= call_user_func($callback, 'c', $from, $from_offset, $n, ''); + $from_offset += $n; + } + else if ( $opcode === 'd' ) { // delete n characters from source + $out .= call_user_func($callback, 'd', $from, $from_offset, $n, ''); + $from_offset += $n; + } + else /* if ( $opcode === 'i' ) */ { // insert n characters from opcodes + $out .= call_user_func($callback, 'i', $opcodes, $opcodes_offset + 1, $n); + $opcodes_offset += 1 + $n; + } + } + return $out; + } + + /** + * Stock granularity stacks and delimiters + */ + + const paragraphDelimiters = "\n\r"; + public static $paragraphGranularity = array( + FineDiff::paragraphDelimiters + ); + const sentenceDelimiters = ".\n\r"; + public static $sentenceGranularity = array( + FineDiff::paragraphDelimiters, + FineDiff::sentenceDelimiters + ); + const wordDelimiters = " \t.\n\r"; + public static $wordGranularity = array( + FineDiff::paragraphDelimiters, + FineDiff::sentenceDelimiters, + FineDiff::wordDelimiters + ); + const characterDelimiters = ""; + public static $characterGranularity = array( + FineDiff::paragraphDelimiters, + FineDiff::sentenceDelimiters, + FineDiff::wordDelimiters, + FineDiff::characterDelimiters + ); + + public static $textStack = array( + ".", + " \t.\n\r", + "" + ); + + /**------------------------------------------------------------------------ + * + * Private section + * + */ + + /** + * Entry point to compute the diff. + */ + private function doDiff($from_text, $to_text) { + $this->last_edit = false; + $this->stackpointer = 0; + $this->from_text = $from_text; + $this->from_offset = 0; + // can't diff without at least one granularity specifier + if ( empty($this->granularityStack) ) { + return; + } + $this->_processGranularity($from_text, $to_text); + } + + /** + * This is the recursive function which is responsible for + * handling/increasing granularity. + * + * Incrementally increasing the granularity is key to compute the + * overall diff in a very efficient way. + */ + private function _processGranularity($from_segment, $to_segment) { + $delimiters = $this->granularityStack[$this->stackpointer++]; + $has_next_stage = $this->stackpointer < count($this->granularityStack); + foreach ( FineDiff::doFragmentDiff($from_segment, $to_segment, $delimiters) as $fragment_edit ) { + // increase granularity + if ( $fragment_edit instanceof FineDiffReplaceOp && $has_next_stage ) { + $this->_processGranularity( + substr($this->from_text, $this->from_offset, $fragment_edit->getFromLen()), + $fragment_edit->getText() + ); + } + // fuse copy ops whenever possible + else if ( $fragment_edit instanceof FineDiffCopyOp && $this->last_edit instanceof FineDiffCopyOp ) { + $this->edits[count($this->edits)-1]->increase($fragment_edit->getFromLen()); + $this->from_offset += $fragment_edit->getFromLen(); + } + else { + /* $fragment_edit instanceof FineDiffCopyOp */ + /* $fragment_edit instanceof FineDiffDeleteOp */ + /* $fragment_edit instanceof FineDiffInsertOp */ + $this->edits[] = $this->last_edit = $fragment_edit; + $this->from_offset += $fragment_edit->getFromLen(); + } + } + $this->stackpointer--; + } + + /** + * This is the core algorithm which actually perform the diff itself, + * fragmenting the strings as per specified delimiters. + * + * This function is naturally recursive, however for performance purpose + * a local job queue is used instead of outright recursivity. + */ + private static function doFragmentDiff($from_text, $to_text, $delimiters) { + // Empty delimiter means character-level diffing. + // In such case, use code path optimized for character-level + // diffing. + if ( empty($delimiters) ) { + return FineDiff::doCharDiff($from_text, $to_text); + } + + $result = array(); + + // fragment-level diffing + $from_text_len = strlen($from_text); + $to_text_len = strlen($to_text); + $from_fragments = FineDiff::extractFragments($from_text, $delimiters); + $to_fragments = FineDiff::extractFragments($to_text, $delimiters); + + $jobs = array(array(0, $from_text_len, 0, $to_text_len)); + + $cached_array_keys = array(); + + while ( $job = array_pop($jobs) ) { + + // get the segments which must be diff'ed + list($from_segment_start, $from_segment_end, $to_segment_start, $to_segment_end) = $job; + + // catch easy cases first + $from_segment_length = $from_segment_end - $from_segment_start; + $to_segment_length = $to_segment_end - $to_segment_start; + if ( !$from_segment_length || !$to_segment_length ) { + if ( $from_segment_length ) { + $result[$from_segment_start * 4] = new FineDiffDeleteOp($from_segment_length); + } + else if ( $to_segment_length ) { + $result[$from_segment_start * 4 + 1] = new FineDiffInsertOp(substr($to_text, $to_segment_start, $to_segment_length)); + } + continue; + } + + // find longest copy operation for the current segments + $best_copy_length = 0; + + $from_base_fragment_index = $from_segment_start; + + $cached_array_keys_for_current_segment = array(); + + while ( $from_base_fragment_index < $from_segment_end ) { + $from_base_fragment = $from_fragments[$from_base_fragment_index]; + $from_base_fragment_length = strlen($from_base_fragment); + // performance boost: cache array keys + if ( !isset($cached_array_keys_for_current_segment[$from_base_fragment]) ) { + if ( !isset($cached_array_keys[$from_base_fragment]) ) { + $to_all_fragment_indices = $cached_array_keys[$from_base_fragment] = array_keys($to_fragments, $from_base_fragment, true); + } + else { + $to_all_fragment_indices = $cached_array_keys[$from_base_fragment]; + } + // get only indices which falls within current segment + if ( $to_segment_start > 0 || $to_segment_end < $to_text_len ) { + $to_fragment_indices = array(); + foreach ( $to_all_fragment_indices as $to_fragment_index ) { + if ( $to_fragment_index < $to_segment_start ) { continue; } + if ( $to_fragment_index >= $to_segment_end ) { break; } + $to_fragment_indices[] = $to_fragment_index; + } + $cached_array_keys_for_current_segment[$from_base_fragment] = $to_fragment_indices; + } + else { + $to_fragment_indices = $to_all_fragment_indices; + } + } + else { + $to_fragment_indices = $cached_array_keys_for_current_segment[$from_base_fragment]; + } + // iterate through collected indices + foreach ( $to_fragment_indices as $to_base_fragment_index ) { + $fragment_index_offset = $from_base_fragment_length; + // iterate until no more match + for (;;) { + $fragment_from_index = $from_base_fragment_index + $fragment_index_offset; + if ( $fragment_from_index >= $from_segment_end ) { + break; + } + $fragment_to_index = $to_base_fragment_index + $fragment_index_offset; + if ( $fragment_to_index >= $to_segment_end ) { + break; + } + if ( $from_fragments[$fragment_from_index] !== $to_fragments[$fragment_to_index] ) { + break; + } + $fragment_length = strlen($from_fragments[$fragment_from_index]); + $fragment_index_offset += $fragment_length; + } + if ( $fragment_index_offset > $best_copy_length ) { + $best_copy_length = $fragment_index_offset; + $best_from_start = $from_base_fragment_index; + $best_to_start = $to_base_fragment_index; + } + } + $from_base_fragment_index += strlen($from_base_fragment); + // If match is larger than half segment size, no point trying to find better + // TODO: Really? + if ( $best_copy_length >= $from_segment_length / 2) { + break; + } + // no point to keep looking if what is left is less than + // current best match + if ( $from_base_fragment_index + $best_copy_length >= $from_segment_end ) { + break; + } + } + + if ( $best_copy_length ) { + $jobs[] = array($from_segment_start, $best_from_start, $to_segment_start, $best_to_start); + $result[$best_from_start * 4 + 2] = new FineDiffCopyOp($best_copy_length); + $jobs[] = array($best_from_start + $best_copy_length, $from_segment_end, $best_to_start + $best_copy_length, $to_segment_end); + } + else { + $result[$from_segment_start * 4 ] = new FineDiffReplaceOp($from_segment_length, substr($to_text, $to_segment_start, $to_segment_length)); + } + } + + ksort($result, SORT_NUMERIC); + return array_values($result); + } + + /** + * Perform a character-level diff. + * + * The algorithm is quite similar to doFragmentDiff(), except that + * the code path is optimized for character-level diff -- strpos() is + * used to find out the longest common subequence of characters. + * + * We try to find a match using the longest possible subsequence, which + * is at most the length of the shortest of the two strings, then incrementally + * reduce the size until a match is found. + * + * I still need to study more the performance of this function. It + * appears that for long strings, the generic doFragmentDiff() is more + * performant. For word-sized strings, doCharDiff() is somewhat more + * performant. + */ + private static function doCharDiff($from_text, $to_text) { + $result = array(); + $jobs = array(array(0, strlen($from_text), 0, strlen($to_text))); + while ( $job = array_pop($jobs) ) { + // get the segments which must be diff'ed + list($from_segment_start, $from_segment_end, $to_segment_start, $to_segment_end) = $job; + $from_segment_len = $from_segment_end - $from_segment_start; + $to_segment_len = $to_segment_end - $to_segment_start; + + // catch easy cases first + if ( !$from_segment_len || !$to_segment_len ) { + if ( $from_segment_len ) { + $result[$from_segment_start * 4 + 0] = new FineDiffDeleteOp($from_segment_len); + } + else if ( $to_segment_len ) { + $result[$from_segment_start * 4 + 1] = new FineDiffInsertOp(substr($to_text, $to_segment_start, $to_segment_len)); + } + continue; + } + if ( $from_segment_len >= $to_segment_len ) { + $copy_len = $to_segment_len; + while ( $copy_len ) { + $to_copy_start = $to_segment_start; + $to_copy_start_max = $to_segment_end - $copy_len; + while ( $to_copy_start <= $to_copy_start_max ) { + $from_copy_start = strpos(substr($from_text, $from_segment_start, $from_segment_len), substr($to_text, $to_copy_start, $copy_len)); + if ( $from_copy_start !== false ) { + $from_copy_start += $from_segment_start; + break 2; + } + $to_copy_start++; + } + $copy_len--; + } + } + else { + $copy_len = $from_segment_len; + while ( $copy_len ) { + $from_copy_start = $from_segment_start; + $from_copy_start_max = $from_segment_end - $copy_len; + while ( $from_copy_start <= $from_copy_start_max ) { + $to_copy_start = strpos(substr($to_text, $to_segment_start, $to_segment_len), substr($from_text, $from_copy_start, $copy_len)); + if ( $to_copy_start !== false ) { + $to_copy_start += $to_segment_start; + break 2; + } + $from_copy_start++; + } + $copy_len--; + } + } + // match found + if ( $copy_len ) { + $jobs[] = array($from_segment_start, $from_copy_start, $to_segment_start, $to_copy_start); + $result[$from_copy_start * 4 + 2] = new FineDiffCopyOp($copy_len); + $jobs[] = array($from_copy_start + $copy_len, $from_segment_end, $to_copy_start + $copy_len, $to_segment_end); + } + // no match, so delete all, insert all + else { + $result[$from_segment_start * 4] = new FineDiffReplaceOp($from_segment_len, substr($to_text, $to_segment_start, $to_segment_len)); + } + } + ksort($result, SORT_NUMERIC); + return array_values($result); + } + + /** + * Efficiently fragment the text into an array according to + * specified delimiters. + * No delimiters means fragment into single character. + * The array indices are the offset of the fragments into + * the input string. + * A sentinel empty fragment is always added at the end. + * Careful: No check is performed as to the validity of the + * delimiters. + */ + private static function extractFragments($text, $delimiters) { + // special case: split into characters + if ( empty($delimiters) ) { + $chars = str_split($text, 1); + $chars[strlen($text)] = ''; + return $chars; + } + $fragments = array(); + $start = $end = 0; + for (;;) { + $end += strcspn($text, $delimiters, $end); + $end += strspn($text, $delimiters, $end); + if ( $end === $start ) { + break; + } + $fragments[$start] = substr($text, $start, $end - $start); + $start = $end; + } + $fragments[$start] = ''; + return $fragments; + } + + /** + * Stock opcode renderers + */ + private static function renderToTextFromOpcode($opcode, $from, $from_offset, $from_len) { + if ( $opcode === 'c' || $opcode === 'i' ) { + return substr($from, $from_offset, $from_len); + } + return ''; + } + + private static function renderDiffToHTMLFromOpcode($opcode, $from, $from_offset, $from_len) { + if ( $opcode === 'c' ) { + return htmlentities(substr($from, $from_offset, $from_len)); + } + else if ( $opcode === 'd' ) { + $deletion = substr($from, $from_offset, $from_len); + if ( strcspn($deletion, " \n\r") === 0 ) { + $deletion = str_replace(array("\n","\r"), array('\n','\r'), $deletion); + } + return '' . htmlentities($deletion) . ''; + } + else /* if ( $opcode === 'i' ) */ { + return '' . htmlentities(substr($from, $from_offset, $from_len)) . ''; + } + return ''; + } + } + diff --git a/plugins/libkolab/vendor/finediff_modifications.diff b/plugins/libkolab/vendor/finediff_modifications.diff new file mode 100644 index 00000000..3a9ad5c9 --- /dev/null +++ b/plugins/libkolab/vendor/finediff_modifications.diff @@ -0,0 +1,121 @@ +--- finediff.php.orig 2014-07-29 14:24:10.000000000 +0200 ++++ finediff.php 2014-07-29 14:30:38.000000000 +0200 +@@ -234,25 +234,25 @@ + + public function renderDiffToHTML() { + $in_offset = 0; +- ob_start(); ++ $html = ''; + foreach ( $this->edits as $edit ) { + $n = $edit->getFromLen(); + if ( $edit instanceof FineDiffCopyOp ) { +- FineDiff::renderDiffToHTMLFromOpcode('c', $this->from_text, $in_offset, $n); ++ $html .= FineDiff::renderDiffToHTMLFromOpcode('c', $this->from_text, $in_offset, $n); + } + else if ( $edit instanceof FineDiffDeleteOp ) { +- FineDiff::renderDiffToHTMLFromOpcode('d', $this->from_text, $in_offset, $n); ++ $html .= FineDiff::renderDiffToHTMLFromOpcode('d', $this->from_text, $in_offset, $n); + } + else if ( $edit instanceof FineDiffInsertOp ) { +- FineDiff::renderDiffToHTMLFromOpcode('i', $edit->getText(), 0, $edit->getToLen()); ++ $html .= FineDiff::renderDiffToHTMLFromOpcode('i', $edit->getText(), 0, $edit->getToLen()); + } + else /* if ( $edit instanceof FineDiffReplaceOp ) */ { +- FineDiff::renderDiffToHTMLFromOpcode('d', $this->from_text, $in_offset, $n); +- FineDiff::renderDiffToHTMLFromOpcode('i', $edit->getText(), 0, $edit->getToLen()); ++ $html .= FineDiff::renderDiffToHTMLFromOpcode('d', $this->from_text, $in_offset, $n); ++ $html .= FineDiff::renderDiffToHTMLFromOpcode('i', $edit->getText(), 0, $edit->getToLen()); + } + $in_offset += $n; + } +- return ob_get_clean(); ++ return $html; + } + + /**------------------------------------------------------------------------ +@@ -277,18 +277,14 @@ + * Re-create the "To" string from the "From" string and an "Opcodes" string + */ + public static function renderToTextFromOpcodes($from, $opcodes) { +- ob_start(); +- FineDiff::renderFromOpcodes($from, $opcodes, array('FineDiff','renderToTextFromOpcode')); +- return ob_get_clean(); ++ return FineDiff::renderFromOpcodes($from, $opcodes, array('FineDiff','renderToTextFromOpcode')); + } + + /**------------------------------------------------------------------------ + * Render the diff to an HTML string + */ + public static function renderDiffToHTMLFromOpcodes($from, $opcodes) { +- ob_start(); +- FineDiff::renderFromOpcodes($from, $opcodes, array('FineDiff','renderDiffToHTMLFromOpcode')); +- return ob_get_clean(); ++ return FineDiff::renderFromOpcodes($from, $opcodes, array('FineDiff','renderDiffToHTMLFromOpcode')); + } + + /**------------------------------------------------------------------------ +@@ -297,8 +293,9 @@ + */ + public static function renderFromOpcodes($from, $opcodes, $callback) { + if ( !is_callable($callback) ) { +- return; ++ return ''; + } ++ $out = ''; + $opcodes_len = strlen($opcodes); + $from_offset = $opcodes_offset = 0; + while ( $opcodes_offset < $opcodes_len ) { +@@ -312,18 +309,19 @@ + $n = 1; + } + if ( $opcode === 'c' ) { // copy n characters from source +- call_user_func($callback, 'c', $from, $from_offset, $n, ''); ++ $out .= call_user_func($callback, 'c', $from, $from_offset, $n, ''); + $from_offset += $n; + } + else if ( $opcode === 'd' ) { // delete n characters from source +- call_user_func($callback, 'd', $from, $from_offset, $n, ''); ++ $out .= call_user_func($callback, 'd', $from, $from_offset, $n, ''); + $from_offset += $n; + } + else /* if ( $opcode === 'i' ) */ { // insert n characters from opcodes +- call_user_func($callback, 'i', $opcodes, $opcodes_offset + 1, $n); ++ $out .= call_user_func($callback, 'i', $opcodes, $opcodes_offset + 1, $n); + $opcodes_offset += 1 + $n; + } + } ++ return $out; + } + + /** +@@ -665,24 +663,26 @@ + */ + private static function renderToTextFromOpcode($opcode, $from, $from_offset, $from_len) { + if ( $opcode === 'c' || $opcode === 'i' ) { +- echo substr($from, $from_offset, $from_len); ++ return substr($from, $from_offset, $from_len); + } ++ return ''; + } + + private static function renderDiffToHTMLFromOpcode($opcode, $from, $from_offset, $from_len) { + if ( $opcode === 'c' ) { +- echo htmlentities(substr($from, $from_offset, $from_len)); ++ return htmlentities(substr($from, $from_offset, $from_len)); + } + else if ( $opcode === 'd' ) { + $deletion = substr($from, $from_offset, $from_len); + if ( strcspn($deletion, " \n\r") === 0 ) { + $deletion = str_replace(array("\n","\r"), array('\n','\r'), $deletion); + } +- echo '', htmlentities($deletion), ''; ++ return '' . htmlentities($deletion) . ''; + } + else /* if ( $opcode === 'i' ) */ { +- echo '', htmlentities(substr($from, $from_offset, $from_len)), ''; ++ return '' . htmlentities(substr($from, $from_offset, $from_len)) . ''; + } ++ return ''; + } + } +