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phab/src/applications/differential/parser/DifferentialCommitMessageParser.php
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DifferentialCommitMessageParser.php
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<?php
/**
* Parses commit messages (containing relaively freeform text with textual
* field labels) into a dictionary of fields.
*
* $parser = id(new DifferentialCommitMessageParser())
* ->setLabelMap($label_map)
* ->setTitleKey($key_title)
* ->setSummaryKey($key_summary);
*
* $fields = $parser->parseCorpus($corpus);
* $errors = $parser->getErrors();
*
* This is used by Differential to parse messages entered from the command line.
*
* @task config Configuring the Parser
* @task parse Parsing Messages
* @task support Support Methods
* @task internal Internals
*/
final class DifferentialCommitMessageParser {
private $labelMap;
private $titleKey;
private $summaryKey;
private $errors;
/* -( Configuring the Parser )--------------------------------------------- */
/**
* @task config
*/
public function setLabelMap(array $label_map) {
$this->labelMap = $label_map;
return $this;
}
/**
* @task config
*/
public function setTitleKey($title_key) {
$this->titleKey = $title_key;
return $this;
}
/**
* @task config
*/
public function setSummaryKey($summary_key) {
$this->summaryKey = $summary_key;
return $this;
}
/* -( Parsing Messages )--------------------------------------------------- */
/**
* @task parse
*/
public function parseCorpus($corpus) {
$this->errors = array();
$label_map = $this->labelMap;
$key_title = $this->titleKey;
$key_summary = $this->summaryKey;
if (!$key_title || !$key_summary || ($label_map === null)) {
throw new Exception(
pht(
'Expected labelMap, summaryKey and titleKey to be set before '.
'parsing a corpus.'));
}
$label_regexp = $this->buildLabelRegexp($label_map);
// NOTE: We're special casing things here to make the "Title:" label
// optional in the message.
$field = $key_title;
$seen = array();
$lines = explode("\n", trim($corpus));
$field_map = array();
foreach ($lines as $key => $line) {
$match = null;
if (preg_match($label_regexp, $line, $match)) {
$lines[$key] = trim($match['text']);
$field = $label_map[self::normalizeFieldLabel($match['field'])];
if (!empty($seen[$field])) {
$this->errors[] = pht(
'Field "%s" occurs twice in commit message!',
$field);
}
$seen[$field] = true;
}
$field_map[$key] = $field;
}
$fields = array();
foreach ($lines as $key => $line) {
$fields[$field_map[$key]][] = $line;
}
// This is a piece of special-cased magic which allows you to omit the
// field labels for "title" and "summary". If the user enters a large block
// of text at the beginning of the commit message with an empty line in it,
// treat everything before the blank line as "title" and everything after
// as "summary".
if (isset($fields[$key_title]) && empty($fields[$key_summary])) {
$lines = $fields[$key_title];
for ($ii = 0; $ii < count($lines); $ii++) {
if (strlen(trim($lines[$ii])) == 0) {
break;
}
}
if ($ii != count($lines)) {
$fields[$key_title] = array_slice($lines, 0, $ii);
$summary = array_slice($lines, $ii);
if (strlen(trim(implode("\n", $summary)))) {
$fields[$key_summary] = $summary;
}
}
}
// Implode all the lines back into chunks of text.
foreach ($fields as $name => $lines) {
$data = rtrim(implode("\n", $lines));
$data = ltrim($data, "\n");
$fields[$name] = $data;
}
// This is another piece of special-cased magic which allows you to
// enter a ridiculously long title, or just type a big block of stream
// of consciousness text, and have some sort of reasonable result conjured
// from it.
if (isset($fields[$key_title])) {
$terminal = '...';
$title = $fields[$key_title];
$short = phutil_utf8_shorten($title, 250, $terminal);
if ($short != $title) {
// If we shortened the title, split the rest into the summary, so
// we end up with a title like:
//
// Title title tile title title...
//
// ...and a summary like:
//
// ...title title title.
//
// Summary summary summary summary.
$summary = idx($fields, $key_summary, '');
$offset = strlen($short) - strlen($terminal);
$remainder = ltrim(substr($fields[$key_title], $offset));
$summary = '...'.$remainder."\n\n".$summary;
$summary = rtrim($summary, "\n");
$fields[$key_title] = $short;
$fields[$key_summary] = $summary;
}
}
return $fields;
}
/**
* @task parse
*/
public function getErrors() {
return $this->errors;
}
/* -( Support Methods )---------------------------------------------------- */
/**
* @task support
*/
public static function normalizeFieldLabel($label) {
return phutil_utf8_strtolower($label);
}
/* -( Internals )---------------------------------------------------------- */
/**
* @task internal
*/
private function buildLabelRegexp(array $label_map) {
$field_labels = array_keys($label_map);
foreach ($field_labels as $key => $label) {
$field_labels[$key] = preg_quote($label, '/');
}
$field_labels = implode('|', $field_labels);
$field_pattern = '/^(?P<field>'.$field_labels.'):(?P<text>.*)$/i';
return $field_pattern;
}
}
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