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phab/src/applications/diffusion/query/lowlevel/DiffusionLowLevelResolveRefsQuery.php
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DiffusionLowLevelResolveRefsQuery.php
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<?php
/**
* Resolves references (like short commit names, branch names, tag names, etc.)
* into canonical, stable commit identifiers. This query works for all
* repository types.
*/
final class DiffusionLowLevelResolveRefsQuery
extends DiffusionLowLevelQuery {
private $refs;
public function withRefs(array $refs) {
$this->refs = $refs;
return $this;
}
public function executeQuery() {
if (!$this->refs) {
return array();
}
switch ($this->getRepository()->getVersionControlSystem()) {
case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
$result = $this->resolveGitRefs();
break;
case PhabricatorRepositoryType::REPOSITORY_TYPE_MERCURIAL:
$result = $this->resolveMercurialRefs();
break;
case PhabricatorRepositoryType::REPOSITORY_TYPE_SVN:
$result = $this->resolveSubversionRefs();
break;
default:
throw new Exception('Unsupported repository type!');
}
return $result;
}
private function resolveGitRefs() {
$repository = $this->getRepository();
$future = $repository->getLocalCommandFuture('cat-file --batch-check');
$future->write(implode("\n", $this->refs));
list($stdout) = $future->resolvex();
$lines = explode("\n", rtrim($stdout, "\n"));
if (count($lines) !== count($this->refs)) {
throw new Exception('Unexpected line count from `git cat-file`!');
}
$hits = array();
$tags = array();
$lines = array_combine($this->refs, $lines);
foreach ($lines as $ref => $line) {
$parts = explode(' ', $line);
if (count($parts) < 2) {
throw new Exception("Failed to parse `git cat-file` output: {$line}");
}
list($identifier, $type) = $parts;
if ($type == 'missing') {
// This is either an ambiguous reference which resolves to several
// objects, or an invalid reference. For now, always treat it as
// invalid. It would be nice to resolve all possibilities for
// ambiguous references at some point, although the strategy for doing
// so isn't clear to me.
continue;
}
switch ($type) {
case 'commit':
break;
case 'tag':
$tags[] = $identifier;
break;
default:
throw new Exception(
"Unexpected object type from `git cat-file`: {$line}");
}
$hits[] = array(
'ref' => $ref,
'type' => $type,
'identifier' => $identifier,
);
}
$tag_map = array();
if ($tags) {
// If some of the refs were tags, just load every tag in order to figure
// out which commits they map to. This might be somewhat inefficient in
// repositories with a huge number of tags.
$tag_refs = id(new DiffusionLowLevelGitRefQuery())
->setRepository($repository)
->withIsTag(true)
->executeQuery();
foreach ($tag_refs as $tag_ref) {
$tag_map[$tag_ref->getShortName()] = $tag_ref->getCommitIdentifier();
}
}
$results = array();
foreach ($hits as $hit) {
$type = $hit['type'];
$ref = $hit['ref'];
$alternate = null;
if ($type == 'tag') {
$alternate = $identifier;
$identifier = idx($tag_map, $ref);
if (!$identifier) {
throw new Exception("Failed to look up tag '{$ref}'!");
}
}
$result = array(
'type' => $type,
'identifier' => $identifier,
);
if ($alternate !== null) {
$result['alternate'] = $alternate;
}
$results[$ref][] = $result;
}
return $results;
}
private function resolveMercurialRefs() {
$repository = $this->getRepository();
$futures = array();
foreach ($this->refs as $ref) {
// TODO: There was a note about `--rev 'a b'` not working for branches
// with spaces in their names in older code, but I suspect this was
// misidentified and resulted from the branch name being interpeted as
// a revset. Use hgsprintf() to avoid that. If this doesn't break for a
// bit, remove this comment. Otherwise, consider `-b %s --limit 1`.
$futures[$ref] = $repository->getLocalCommandFuture(
'log --template=%s --rev %s',
'{node}',
hgsprintf('%s', $ref));
}
$results = array();
foreach (Futures($futures) as $ref => $future) {
try {
list($stdout) = $future->resolvex();
} catch (CommandException $ex) {
if (preg_match('/ambiguous identifier/', $ex->getStdErr())) {
// This indicates that the ref ambiguously matched several things.
// Eventually, it would be nice to return all of them, but it is
// unclear how to best do that. For now, treat it as a miss instead.
continue;
}
throw $ex;
}
// It doesn't look like we can figure out the type (commit/branch/rev)
// from this output very easily. For now, just call everything a commit.
$type = 'commit';
$results[$ref][] = array(
'type' => $type,
'identifier' => trim($stdout),
);
}
return $results;
}
private function resolveSubversionRefs() {
$repository = $this->getRepository();
$max_commit = id(new PhabricatorRepositoryCommit())
->loadOneWhere(
'repositoryID = %d ORDER BY epoch DESC, id DESC LIMIT 1',
$repository->getID());
if (!$max_commit) {
// This repository is empty or hasn't parsed yet, so none of the refs are
// going to resolve.
return array();
}
$max_commit_id = (int)$max_commit->getCommitIdentifier();
$results = array();
foreach ($this->refs as $ref) {
if ($ref == 'HEAD') {
// Resolve "HEAD" to mean "the most recent commit".
$results[$ref][] = array(
'type' => 'commit',
'identifier' => $max_commit_id,
);
continue;
}
if (!preg_match('/^\d+$/', $ref)) {
// This ref is non-numeric, so it doesn't resolve to anything.
continue;
}
// Resolve other commits if we can deduce their existence.
// TODO: When we import only part of a repository, we won't necessarily
// have all of the smaller commits. Should we fail to resolve them here
// for repositories with a subpath? It might let us simplify other things
// elsewhere.
if ((int)$ref <= $max_commit_id) {
$results[$ref][] = array(
'type' => 'commit',
'identifier' => (int)$ref,
);
}
}
return $results;
}
}
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