Differential D16071 Diff 38672 src/utils/PhutilProseDiff.php

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src/utils/PhutilProseDiff.php

Show All 14 Lines	final class PhutilProseDiff extends Phobject {
public function getParts() {		public function getParts() {
return $this->parts;		return $this->parts;
}		}

public function reorderParts() {		public function reorderParts() {
// Reorder sequences of removed and added sections to put all the "-"		// Reorder sequences of removed and added sections to put all the "-"
// parts together first, then all the "+" parts together. This produces		// parts together first, then all the "+" parts together. This produces
// a more human-readable result than intermingling them.		// a more human-readable result than intermingling them.

$o_run = array();		$o_run = array();
$n_run = array();		$n_run = array();
$result = array();		$result = array();
foreach ($this->parts as $part) {		foreach ($this->parts as $part) {
$type = $part['type'];		$type = $part['type'];
switch ($type) {		switch ($type) {
case '-':		case '-':
$o_run[] = $part;		$o_run[] = $part;
break;		break;
case '+':		case '+':
$n_run[] = $part;		$n_run[] = $part;
break;		break;
default:		default:
foreach ($o_run as $o) {		if ($o_run \|\| $n_run) {
$result[] = $o;		foreach ($this->combineRuns($o_run, $n_run) as $merged_part) {
}		$result[] = $merged_part;
foreach ($n_run as $n) {
$result[] = $n;
}		}
$result[] = $part;
$o_run = array();		$o_run = array();
$n_run = array();		$n_run = array();
		}
		$result[] = $part;
break;		break;
}		}
}		}

foreach ($o_run as $o) {		if ($o_run \|\| $n_run) {
$result[] = $o;		foreach ($this->combineRuns($o_run, $n_run) as $part) {
		$result[] = $part;
}		}
foreach ($n_run as $n) {
$result[] = $n;
}		}

// Now, combine consecuitive runs of the same type of change (like a		// Now, combine consecuitive runs of the same type of change (like a
// series of "-" parts) into a single run.		// series of "-" parts) into a single run.
$combined = array();		$combined = array();

$last = null;		$last = null;
$last_text = null;		$last_text = null;
Show All 21 Lines	if ($last_text !== null) {
);		);
}		}

$this->parts = $combined;		$this->parts = $combined;

return $this;		return $this;
}		}

		private function combineRuns($o_run, $n_run) {
		$o_merge = $this->mergeParts($o_run);
		$n_merge = $this->mergeParts($n_run);

		// When removed and added blocks share a prefix or suffix, we sometimes
		// want to count it as unchanged (for example, if it is whitespace) but
		// sometimes want to count it as changed (for example, if it is a word
		// suffix like "ing"). Find common prefixes and suffixes of these layout
		// characters and emit them as "=" (unchanged) blocks.

		$layout_characters = array(
		' ' => true,
		"\n" => true,
		'.' => true,
		'!' => true,
		',' => true,
		'?' => true,
		);

		$o_text = $o_merge['text'];
		$n_text = $n_merge['text'];
		$o_len = strlen($o_text);
		$n_len = strlen($n_text);
		$min_len = min($o_len, $n_len);

		$prefix_len = 0;
		for ($pos = 0; $pos < $min_len; $pos++) {
		$o = $o_text[$pos];
		$n = $n_text[$pos];
		if ($o !== $n) {
		break;
		}
		if (empty($layout_characters[$o])) {
		break;
		}
		$prefix_len++;
		}

		$suffix_len = 0;
		for ($pos = 1; $pos <= $min_len; $pos++) {
		$o = $o_text[$o_len - $pos];
		$n = $n_text[$n_len - $pos];
		if ($o !== $n) {
		break;
		}
		if (empty($layout_characters[$o])) {
		break;
		}
		$suffix_len++;
		}

		$results = array();

		if ($prefix_len) {
		$results[] = array(
		'type' => '=',
		'text' => substr($o_text, 0, $prefix_len),
		);
		}

		if ($prefix_len < $o_len) {
		$results[] = array(
		'type' => '-',
		'text' => substr($o_text, $prefix_len, $o_len - $suffix_len),
		);
		}

		if ($prefix_len < $n_len) {
		$results[] = array(
		'type' => '+',
		'text' => substr($n_text, $prefix_len, $n_len - $suffix_len),
		);
		}

		if ($suffix_len) {
		$results[] = array(
		'type' => '=',
		'text' => substr($o_text, -$suffix_len),
		);
		}

		return $results;
		}

		private function mergeParts(array $parts) {
		$text = '';
		$type = null;
		foreach ($parts as $part) {
		$part_type = $part['type'];
		if ($type === null) {
		$type = $part_type;
		}
		if ($type !== $part_type) {
		throw new Exception(pht('Can not merge parts of dissimilar types!'));
		}
		$text .= $part['text'];
		}

		return array(
		'type' => $type,
		'text' => $text,
		);
		}


}		}