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DivinerGenerateWorkflow.php
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Sat, Jan 18, 15:43

DivinerGenerateWorkflow.php
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<?php
final class DivinerGenerateWorkflow extends DivinerWorkflow {
public function didConstruct() {
$this
->setName('generate')
->setSynopsis(pht('Generate documentation.'))
->setArguments(
array(
array(
'name' => 'clean',
'help' => 'Clear the caches before generating documentation.',
),
));
}
public function execute(PhutilArgumentParser $args) {
if ($args->getArg('clean')) {
$this->log(pht('CLEARING CACHES'));
$this->getAtomCache()->delete();
}
// The major challenge of documentation generation is one of dependency
// management. When regenerating documentation, we want to do the smallest
// amount of work we can, so that regenerating documentation after minor
// changes is quick.
//
// ATOM CACHE
//
// In the first stage, we find all the direct changes to source code since
// the last run. This stage relies on two data structures:
//
// - File Hash Map: map<file_hash, node_hash>
// - Atom Map: map<node_hash, true>
//
// First, we hash all the source files in the project to detect any which
// have changed since the previous run (i.e., their hash is not present in
// the File Hash Map). If a file's content hash appears in the map, it has
// not changed, so we don't need to reparse it.
//
// We break the contents of each file into "atoms", which represent a unit
// of source code (like a function, method, class or file). Each atom has a
// "node hash" based on the content of the atom: if a function definition
// changes, the node hash of the atom changes too. The primary output of
// the atom cache is a list of node hashes which exist in the project. This
// is the Atom Map. The node hash depends only on the definition of the atom
// and the atomizer implementation. It ends with an "N", for "node".
//
// (We need the Atom Map in addition to the File Hash Map because each file
// may have several atoms in it (e.g., multiple functions, or a class and
// its methods). The File Hash Map contains an exhaustive list of all atoms
// with type "file", but not child atoms of those top-level atoms.)
//
// GRAPH CACHE
//
// We now know which atoms exist, and can compare the Atom Map to some
// existing cache to figure out what has changed. However, this isn't
// sufficient to figure out which documentation actually needs to be
// regnerated, because atoms depend on other atoms. For example, if "B
// extends A" and the definition for A changes, we need to regenerate the
// documentation in B. Similarly, if X links to Y and Y changes, we should
// regenerate X. (In both these cases, the documentation for the connected
// atom may not acutally change, but in some cases it will, and the extra
// work we need to do is generally very small compared to the size of the
// project.)
//
// To figure out which other nodes have changed, we compute a "graph hash"
// for each node. This hash combines the "node hash" with the node hashes
// of connected nodes. Our primary output is a list of graph hashes, which
// a documentation generator can use to easily determine what work needs
// to be done by comparing the list with a list of cached graph hashes,
// then generating documentation for new hashes and deleting documentation
// for missing hashes. The graph hash ends with a "G", for "graph".
//
// In this stage, we rely on three data structures:
//
// - Symbol Map: map<node_hash, symbol_hash>
// - Edge Map: map<node_hash, list<symbol_hash>>
// - Graph Map: map<node_hash, graph_hash>
//
// Calculating the graph hash requires several steps, because we need to
// figure out which nodes an atom is attached to. The atom contains symbolic
// references to other nodes by name (e.g., "extends SomeClass") in the form
// of DivinerAtomRefs. We can also build a symbolic reference for any atom
// from the atom itself. Each DivinerAtomRef generates a symbol hash,
// which ends with an "S", for "symbol".
//
// First, we update the symbol map. We remove (and mark dirty) any symbols
// associated with node hashes which no longer exist (e.g., old/dead nodes).
// Second, we add (and mark dirty) any symbols associated with new nodes.
// We also add edges defined by new nodes to the graph.
//
// We initialize a list of dirty nodes to the list of new nodes, then
// find all nodes connected to dirty symbols and add them to the dirty
// node list. This list now contains every node with a new or changed
// graph hash.
//
// We walk the dirty list and compute the new graph hashes, adding them
// to the graph hash map. This Graph Map can then be passed to an actual
// documentation generator, which can compare the graph hashes to a list
// of already-generated graph hashes and easily assess which documents need
// to be regenerated and which can be deleted.
$this->buildAtomCache();
$this->buildGraphCache();
}
/* -( Atom Cache )--------------------------------------------------------- */
private function buildAtomCache() {
$this->log(pht('BUILDING ATOM CACHE'));
$file_hashes = $this->findFilesInProject();
$this->log(pht('Found %d file(s) in project.', count($file_hashes)));
$this->deleteDeadAtoms($file_hashes);
$atomize = $this->getFilesToAtomize($file_hashes);
$this->log(pht('Found %d unatomized, uncached file(s).', count($atomize)));
$file_atomizers = $this->getAtomizersForFiles($atomize);
$this->log(pht('Found %d file(s) to atomize.', count($file_atomizers)));
$futures = $this->buildAtomizerFutures($file_atomizers);
if ($futures) {
$this->resolveAtomizerFutures($futures, $file_hashes);
$this->log(pht("Atomization complete."));
} else {
$this->log(pht("Atom cache is up to date, no files to atomize."));
}
$this->log(pht("Writing atom cache."));
$this->getAtomCache()->saveAtoms();
$this->log(pht("Done."));
}
private function getAtomizersForFiles(array $files) {
$rules = $this->getRules();
$atomizers = array();
foreach ($files as $file) {
foreach ($rules as $rule => $atomizer) {
$ok = preg_match($rule, $file);
if ($ok === false) {
throw new Exception(
"Rule '{$rule}' is not a valid regular expression.");
}
if ($ok) {
$atomizers[$file] = $atomizer;
continue;
}
}
}
return $atomizers;
}
private function getRules() {
return $this->getConfig('rules', array()) + array(
'/\\.diviner$/' => 'DivinerArticleAtomizer',
);
}
private function findFilesInProject() {
$file_hashes = id(new FileFinder($this->getRoot()))
->excludePath('*/.*')
->withType('f')
->setGenerateChecksums(true)
->find();
$version = $this->getDivinerAtomWorldVersion();
foreach ($file_hashes as $file => $md5_hash) {
// We want the hash to change if the file moves or Diviner gets updated,
// not just if the file content changes. Derive a hash from everything
// we care about.
$file_hashes[$file] = md5("{$file}\0{$md5_hash}\0{$version}").'F';
}
return $file_hashes;
}
private function deleteDeadAtoms(array $file_hashes) {
$atom_cache = $this->getAtomCache();
$hash_to_file = array_flip($file_hashes);
foreach ($atom_cache->getFileHashMap() as $hash => $atom) {
if (empty($hash_to_file[$hash])) {
$atom_cache->deleteFileHash($hash);
}
}
}
private function getFilesToAtomize(array $file_hashes) {
$atom_cache = $this->getAtomCache();
$atomize = array();
foreach ($file_hashes as $file => $hash) {
if (!$atom_cache->fileHashExists($hash)) {
$atomize[] = $file;
}
}
return $atomize;
}
private function buildAtomizerFutures(array $file_atomizers) {
$atomizers = array();
foreach ($file_atomizers as $file => $atomizer) {
$atomizers[$atomizer][] = $file;
}
$futures = array();
foreach ($atomizers as $class => $files) {
foreach (array_chunk($files, 32) as $chunk) {
$future = new ExecFuture(
'%s atomize --atomizer %s -- %Ls',
dirname(phutil_get_library_root('phabricator')).'/bin/diviner',
$class,
$chunk);
$future->setCWD($this->getRoot());
$futures[] = $future;
}
}
return $futures;
}
private function resolveAtomizerFutures(array $futures, array $file_hashes) {
assert_instances_of($futures, 'Future');
$atom_cache = $this->getAtomCache();
foreach (Futures($futures)->limit(4) as $key => $future) {
$atoms = $future->resolveJSON();
foreach ($atoms as $atom) {
if ($atom['type'] == DivinerAtom::TYPE_FILE) {
$file_hash = $file_hashes[$atom['file']];
$atom_cache->addFileHash($file_hash, $atom['hash']);
}
$atom_cache->addAtom($atom);
}
}
}
/**
* Get a global version number, which changes whenever any atom or atomizer
* implementation changes in a way which is not backward-compatible.
*/
private function getDivinerAtomWorldVersion() {
$version = array();
$version['atom'] = DivinerAtom::getAtomSerializationVersion();
$version['rules'] = $this->getRules();
$atomizers = id(new PhutilSymbolLoader())
->setAncestorClass('DivinerAtomizer')
->setConcreteOnly(true)
->selectAndLoadSymbols();
$atomizer_versions = array();
foreach ($atomizers as $atomizer) {
$atomizer_versions[$atomizer['name']] = call_user_func(
array(
$atomizer['name'],
'getAtomizerVersion',
));
}
ksort($atomizer_versions);
$version['atomizers'] = $atomizer_versions;
return md5(serialize($version));
}
/* -( Graph Cache )-------------------------------------------------------- */
private function buildGraphCache() {
$this->log(pht('BUILDING GRAPH CACHE'));
$atom_cache = $this->getAtomCache();
$symbol_map = $atom_cache->getSymbolMap();
$atoms = $atom_cache->getAtomMap();
$dirty_symbols = array();
$dirty_nhashes = array();
$del_atoms = array_diff_key($symbol_map, $atoms);
$this->log(pht('Found %d obsolete atom(s) in graph.', count($del_atoms)));
foreach ($del_atoms as $nhash => $shash) {
$atom_cache->deleteSymbol($nhash);
$dirty_symbols[$shash] = true;
$atom_cache->deleteEdges($nhash);
$atom_cache->deleteGraph($nhash);
}
$new_atoms = array_diff_key($atoms, $symbol_map);
$this->log(pht('Found %d new atom(s) in graph.', count($new_atoms)));
foreach ($new_atoms as $nhash => $ignored) {
$shash = $this->computeSymbolHash($nhash);
$atom_cache->addSymbol($nhash, $shash);
$dirty_symbols[$shash] = true;
$atom_cache->addEdges(
$nhash,
$this->getEdges($nhash));
$dirty_nhashes[$nhash] = true;
}
$this->log(pht('Propagating changes through the graph.'));
foreach ($dirty_symbols as $symbol => $ignored) {
foreach ($atom_cache->getEdgesWithDestination($symbol) as $edge) {
$dirty_nhashes[$edge] = true;
}
}
$this->log(pht('Found %d affected atoms.', count($dirty_nhashes)));
foreach ($dirty_nhashes as $nhash => $ignored) {
$atom_cache->addGraph($nhash, $this->computeGraphHash($nhash));
}
$this->log(pht('Writing graph cache.'));
$atom_cache->saveGraph();
$atom_cache->saveEdges();
$atom_cache->saveSymbols();
$this->log(pht('Done.'));
}
private function computeSymbolHash($node_hash) {
$atom_cache = $this->getAtomCache();
$atom = $atom_cache->getAtom($node_hash);
$ref = DivinerAtomRef::newFromDictionary($atom['ref']);
return $ref->toHash();
}
private function getEdges($node_hash) {
$atom_cache = $this->getAtomCache();
$atom = $atom_cache->getAtom($node_hash);
$refs = array();
foreach (array_merge($atom['extends'], $atom['links']) as $ref_dict) {
$ref = DivinerAtomRef::newFromDictionary($ref_dict);
if ($ref->getProject() == $atom['project']) {
$refs[$ref->toHash()] = true;
}
}
return array_keys($refs);
}
private function computeGraphHash($node_hash) {
$atom_cache = $this->getAtomCache();
$atom = $atom_cache->getAtom($node_hash);
$edges = $this->getEdges($node_hash);
sort($edges);
$inputs = array(
'atomHash' => $atom['hash'],
'edges' => $edges,
);
return md5(serialize($inputs)).'G';
}
}

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