public function getOpCodes()
{
$op_codes = array();
$file_a = new TempFile();
$file_b = new TempFile();
Filesystem::writeFile($file_a, implode('', $this->a));
Filesystem::writeFile($file_b, implode('', $this->b));
$diff_future = new ExecFuture('diff -U0 %s %s', $file_a, $file_b);
list($err, $stdout, $stderr) = $diff_future->resolve();
if (!in_array($err, array(0, 1))) {
throw new CommandException(pht('`diff` returned unexpected exit code %d', $err), $diff_future->getCommand(), $err, $stdout, $stderr);
}
foreach (phutil_split_lines($stdout) as $line) {
$matches = null;
$regexp = '/^@@ -(\\d+)(?:,(\\d+))? \\+(\\d+)(?:,(\\d+))? @@/';
if (!preg_match($regexp, $line, $matches)) {
continue;
}
// We need to:
// - normalize indices; the ones we get from `diff` are 1-indexed.
// - account for how `diff` represents empty hunks -- essentially, it
// attributes the change to the *previous line* (which may be 0!). This
// differs from Python's difflib.
//
// http://www.gnu.org/software/diffutils/manual/html_node/Detailed-Unified.html:
// If a hunk contains just one line, only its start line number
// appears. Otherwise its line numbers look like 'start,count'. An
// empty hunk is considered to start at the line that follows the
// hunk.
//
// If a hunk and its context contain two or more lines, its line
// numbers look like 'start,count'. Otherwise only its end line
// number appears. An empty hunk is considered to end at the line
// that precedes the hunk.
$i = (int) $matches[1] - 1;
$j = (int) $matches[3] - 1;
if (isset($matches[2]) && $matches[2] !== '') {
$li = (int) $matches[2];
} else {
$li = 1;
}
if (isset($matches[4]) && $matches[4] !== '') {
$lj = (int) $matches[4];
} else {
$lj = 1;
}
if (!($li || $lj)) {
throw new CommandException(pht('Malformed output from `diff`.'), $diff_future->getCommand(), $err, $stdout, $stderr);
}
if ($li === 0) {
$op_codes[] = array('insert', $i + 1, $i + 1, $j, $j + $lj);
} else {
if ($lj === 0) {
$op_codes[] = array('delete', $i, $i + $li, $j, $j);
} else {
$op_codes[] = array('replace', $i, $i + $li, $j, $j + $lj);
}
}
}
return $op_codes;
}
