From 4adf55919c755e301b515d6eeb618250840a55b6 Mon Sep 17 00:00:00 2001
From: epriestley <git@epriestley.com>
Date: Mon, 7 Jan 2013 14:04:23 -0800
Subject: [PATCH] Port Diviner Core to Phabricator

Summary:
This implements most/all of the difficult parts of Diviner on top of Phabricator instead of as standalone components. See T988. In particular, here are the things I want to fix:

**Performance** The Diviner parser works in two stages. The first stage breaks source files into "Atoms". The second stage renders atoms into a display format (e.g., HTML). Diviner currently has a good caching story on the first step of the pipeline, but zero caching in the second step. This means it's very slow, even for a fairly small project like Phabricator. We must re-render every piece of documentation every time, instead of only changed documentation. Most of this diff concerns itself with addressing this problem. There's a fairly large explanatory comment about it, but the trickiest part is that when an atom changes, other atoms (defined in other places) may also change -- for example, if `class B extends A`, editing A should dirty B, even if B is in an entirely different file. We perform analysis in two stages to propagate these changes: first detecting direct changes, then detecting indirect changes. This isn't completely implemented -- we need to propagate 'extends' through more levels -- but I believe it's structurally correct and good enough until we actually document classes.

**Inheritance** Diviner currently has a very weak story on inheritance. I want to inherit a lot more metas/docs. If an interface documents a method, we should just pull that documentation in to every implementation by default (implementations can still override it if they want). It can be shown in grey or something, but it should be desirable and correct to omit documentation of a method implementation when you are implementing a parent. Similarly, I want to pull in inherited methods and @tasks and such. This diff sets up for that, by formalizing "extends" relationships between atoms.

**Overspecialization** Diviner currently specializes atoms (FileAtom, FunctionAtom, ClassAtom, etc.). This is pretty much not useful, because Atomizers (which produce the atoms) need to be highly specialized, and Renderers/Publishers (which consume the atoms) also need to be highly specialized. Nothing interesting actually lives in the atom specializations, and we don't benefit from having them -- it just costs us generality in storage/caches for them. In the new code, I've used a single Atom class to represent any type of atom.

**URIs** We have fairly hideous URIs right now, which are very cumbersome  For in-app doc links, I want to provide nice URIs ("/h/notfications" or similar) which are stable redirects, and probably add remarkup for it: !{notifications} or similar. This diff isn't related to that since it's too premature.

**Search** Once we have a database generation target, we can index the documentation.

**Design** Chad has some nice mocks.

Test Plan: Ran `bin/diviner generate`, `bin/diviner generate --clean`. Saw appropriate graph propagation after edits. This diff doesn't do anything very useful yet.

Reviewers: btrahan, vrana

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T988

Differential Revision: https://secure.phabricator.com/D4340
---
 bin/diviner                                   |   1 +
 scripts/diviner/diviner.php                   |  22 +
 src/__phutil_library_map__.php                |  14 +
 src/applications/diviner/atom/DivinerAtom.php | 289 +++++++++++++
 .../diviner/atom/DivinerAtomRef.php           |  69 ++++
 .../atomizer/DivinerArticleAtomizer.php       |  25 ++
 .../diviner/atomizer/DivinerAtomizer.php      |  45 ++
 .../diviner/atomizer/DivinerFileAtomizer.php  |  14 +
 .../diviner/cache/DivinerAtomCache.php        | 261 ++++++++++++
 .../workflow/DivinerAtomizeWorkflow.php       | 103 +++++
 .../workflow/DivinerGenerateWorkflow.php      | 384 ++++++++++++++++++
 .../diviner/workflow/DivinerWorkflow.php      |  33 ++
 12 files changed, 1260 insertions(+)
 create mode 120000 bin/diviner
 create mode 100755 scripts/diviner/diviner.php
 create mode 100644 src/applications/diviner/atom/DivinerAtom.php
 create mode 100644 src/applications/diviner/atom/DivinerAtomRef.php
 create mode 100644 src/applications/diviner/atomizer/DivinerArticleAtomizer.php
 create mode 100644 src/applications/diviner/atomizer/DivinerAtomizer.php
 create mode 100644 src/applications/diviner/atomizer/DivinerFileAtomizer.php
 create mode 100644 src/applications/diviner/cache/DivinerAtomCache.php
 create mode 100644 src/applications/diviner/workflow/DivinerAtomizeWorkflow.php
 create mode 100644 src/applications/diviner/workflow/DivinerGenerateWorkflow.php
 create mode 100644 src/applications/diviner/workflow/DivinerWorkflow.php

diff --git a/bin/diviner b/bin/diviner
new file mode 120000
index 0000000000..465b7cf593
--- /dev/null
+++ b/bin/diviner
@@ -0,0 +1 @@
+../scripts/diviner/diviner.php
\ No newline at end of file
diff --git a/scripts/diviner/diviner.php b/scripts/diviner/diviner.php
new file mode 100755
index 0000000000..9d866ad0b3
--- /dev/null
+++ b/scripts/diviner/diviner.php
@@ -0,0 +1,22 @@
+#!/usr/bin/env php
+<?php
+
+$root = dirname(dirname(dirname(__FILE__)));
+require_once $root.'/scripts/__init_script__.php';
+
+$args = new PhutilArgumentParser($argv);
+
+$args->setTagline('documentation generator');
+$args->setSynopsis(<<<EOHELP
+**diviner** __command__ [__options__]
+  Generate documentation.
+EOHELP
+);
+$args->parseStandardArguments();
+
+$args->parseWorkflows(
+  array(
+    new DivinerGenerateWorkflow(),
+    new DivinerAtomizeWorkflow(),
+    new PhutilHelpArgumentWorkflow(),
+  ));
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index 722084f576..751c7b60d2 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -422,7 +422,16 @@ phutil_register_library_map(array(
     'DiffusionTagListView' => 'applications/diffusion/view/DiffusionTagListView.php',
     'DiffusionURITestCase' => 'applications/diffusion/request/__tests__/DiffusionURITestCase.php',
     'DiffusionView' => 'applications/diffusion/view/DiffusionView.php',
+    'DivinerArticleAtomizer' => 'applications/diviner/atomizer/DivinerArticleAtomizer.php',
+    'DivinerAtom' => 'applications/diviner/atom/DivinerAtom.php',
+    'DivinerAtomCache' => 'applications/diviner/cache/DivinerAtomCache.php',
+    'DivinerAtomRef' => 'applications/diviner/atom/DivinerAtomRef.php',
+    'DivinerAtomizeWorkflow' => 'applications/diviner/workflow/DivinerAtomizeWorkflow.php',
+    'DivinerAtomizer' => 'applications/diviner/atomizer/DivinerAtomizer.php',
+    'DivinerFileAtomizer' => 'applications/diviner/atomizer/DivinerFileAtomizer.php',
+    'DivinerGenerateWorkflow' => 'applications/diviner/workflow/DivinerGenerateWorkflow.php',
     'DivinerListController' => 'applications/diviner/controller/DivinerListController.php',
+    'DivinerWorkflow' => 'applications/diviner/workflow/DivinerWorkflow.php',
     'DrydockAllocatorWorker' => 'applications/drydock/worker/DrydockAllocatorWorker.php',
     'DrydockApacheWebrootInterface' => 'applications/drydock/interface/webroot/DrydockApacheWebrootInterface.php',
     'DrydockBlueprint' => 'applications/drydock/blueprint/DrydockBlueprint.php',
@@ -1780,7 +1789,12 @@ phutil_register_library_map(array(
     'DiffusionTagListView' => 'DiffusionView',
     'DiffusionURITestCase' => 'ArcanistPhutilTestCase',
     'DiffusionView' => 'AphrontView',
+    'DivinerArticleAtomizer' => 'DivinerAtomizer',
+    'DivinerAtomizeWorkflow' => 'DivinerWorkflow',
+    'DivinerFileAtomizer' => 'DivinerAtomizer',
+    'DivinerGenerateWorkflow' => 'DivinerWorkflow',
     'DivinerListController' => 'PhabricatorController',
+    'DivinerWorkflow' => 'PhutilArgumentWorkflow',
     'DrydockAllocatorWorker' => 'PhabricatorWorker',
     'DrydockApacheWebrootInterface' => 'DrydockWebrootInterface',
     'DrydockCommandInterface' => 'DrydockInterface',
diff --git a/src/applications/diviner/atom/DivinerAtom.php b/src/applications/diviner/atom/DivinerAtom.php
new file mode 100644
index 0000000000..aa8de92cf6
--- /dev/null
+++ b/src/applications/diviner/atom/DivinerAtom.php
@@ -0,0 +1,289 @@
+<?php
+
+final class DivinerAtom {
+
+  const TYPE_FILE      = 'file';
+  const TYPE_ARTICLE   = 'article';
+
+  private $type;
+  private $name;
+  private $file;
+  private $line;
+  private $hash;
+  private $contentRaw;
+  private $length;
+  private $language;
+  private $docblockRaw;
+  private $docblockText;
+  private $docblockMeta;
+  private $warnings = array();
+  private $parentHash;
+  private $childHashes = array();
+  private $context;
+  private $extends = array();
+  private $links = array();
+  private $project;
+
+  public function setProject($project) {
+    $this->project = $project;
+    return $this;
+  }
+
+  public function getProject() {
+    return $this->project;
+  }
+
+  public function setContext($context) {
+    $this->context = $context;
+    return $this;
+  }
+
+  public function getContext() {
+    return $this->context;
+  }
+
+  public static function getAtomSerializationVersion() {
+    return 1;
+  }
+
+  public function addWarning($warning) {
+    $this->warnings[] = $warning;
+    return $this;
+  }
+
+  public function getWarnings() {
+    return $this->warnings;
+  }
+
+  public function setDocblockRaw($docblock_raw) {
+    $this->docblockRaw = $docblock_raw;
+
+    $parser = new PhutilDocblockParser();
+    list($text, $meta) = $parser->parse($docblock_raw);
+    $this->docblockText = $text;
+    $this->docblockMeta = $meta;
+
+    return $this;
+  }
+
+  public function getDocblockRaw() {
+    return $this->docblockRaw;
+  }
+
+  public function getDocblockText() {
+    if ($this->docblockText === null) {
+      throw new Exception("Call setDocblockRaw() before getDocblockText()!");
+    }
+    return $this->docblockText;
+  }
+
+  public function getDocblockMeta() {
+    if ($this->docblockMeta === null) {
+      throw new Exception("Call setDocblockRaw() before getDocblockMeta()!");
+    }
+    return $this->docblockMeta;
+  }
+
+  public function setType($type) {
+    $this->type = $type;
+    return $this;
+  }
+
+  public function getType() {
+    return $this->type;
+  }
+
+  public function setName($name) {
+    $this->name = $name;
+    return $this;
+  }
+
+  public function getName() {
+    return $this->name;
+  }
+
+  public function setFile($file) {
+    $this->file = $file;
+    return $this;
+  }
+
+  public function getFile() {
+    return $this->file;
+  }
+
+  public function setLine($line) {
+    $this->line = $line;
+    return $this;
+  }
+
+  public function getLine() {
+    return $this->line;
+  }
+
+  public function setContentRaw($content_raw) {
+    $this->contentRaw = $content_raw;
+    return $this;
+  }
+
+  public function getContentRaw() {
+    return $this->contentRaw;
+  }
+
+  public function setHash($hash) {
+    $this->hash = $hash;
+    return $this;
+  }
+
+  public function addLink(DivinerAtomRef $ref) {
+    $this->links[] = $ref;
+    return $this;
+  }
+
+  public function addExtends(DivinerAtomRef $ref) {
+    $this->extends[] = $ref;
+    return $this;
+  }
+
+  public function getLinkDictionaries() {
+    return mpull($this->links, 'toDictionary');
+  }
+
+  public function getExtendsDictionaries() {
+    return mpull($this->extends, 'toDictionary');
+  }
+
+  public function getHash() {
+    if ($this->hash) {
+      return $this->hash;
+    }
+
+    $parts = array(
+      $this->getType(),
+      $this->getName(),
+      $this->getFile(),
+      $this->getLine(),
+      $this->getLength(),
+      $this->getLanguage(),
+      $this->getContentRaw(),
+      $this->getDocblockRaw(),
+      mpull($this->extends, 'toHash'),
+      mpull($this->links, 'toHash'),
+    );
+
+    return md5(serialize($parts)).'N';
+  }
+
+  public function setLength($length) {
+    $this->length = $length;
+    return $this;
+  }
+
+  public function getLength() {
+    return $this->length;
+  }
+
+  public function setLanguage($language) {
+    $this->language = $language;
+    return $this;
+  }
+
+  public function getLanguage() {
+    return $this->language;
+  }
+
+  public function addChildHash($child_hash) {
+    $this->childHashes[] = $child_hash;
+    return $this;
+  }
+
+  public function getChildHashes() {
+    return $this->childHashes;
+  }
+
+  public function setParentHash($parent_hash) {
+    if ($this->parentHash) {
+      throw new Exception("Atom already has a parent!");
+    }
+    $this->parentHash = $parent_hash;
+    return $this;
+  }
+
+  public function getParentHash() {
+    return $this->parentHash;
+  }
+
+  public function addChild(DivinerAtom $atom) {
+    $atom->setParentHash($this->getHash());
+    $this->addChildHash($atom->getHash());
+    return $this;
+  }
+
+  public function getURI() {
+    $parts = array();
+    $parts[] = phutil_escape_uri_path_component($this->getType());
+    if ($this->getContext()) {
+      $parts[] = phutil_escape_uri_path_component($this->getContext());
+    }
+    $parts[] = phutil_escape_uri_path_component($this->getName());
+    $parts[] = null;
+    return implode('/', $parts);
+  }
+
+
+  public function toDictionary() {
+    // NOTE: If you change this format, bump the format version in
+    // getAtomSerializationVersion().
+
+    return array(
+      'type'        => $this->getType(),
+      'name'        => $this->getName(),
+      'file'        => $this->getFile(),
+      'line'        => $this->getLine(),
+      'hash'        => $this->getHash(),
+      'uri'         => $this->getURI(),
+      'length'      => $this->getLength(),
+      'context'     => $this->getContext(),
+      'language'    => $this->getLanguage(),
+      'docblockRaw' => $this->getDocblockRaw(),
+      'warnings'    => $this->getWarnings(),
+      'parentHash'  => $this->getParentHash(),
+      'childHashes' => $this->getChildHashes(),
+      'extends'     => $this->getExtendsDictionaries(),
+      'links'       => $this->getLinkDictionaries(),
+      'ref'         => $this->getRef()->toDictionary(),
+    );
+  }
+
+  public function getRef() {
+    return id(new DivinerAtomRef())
+      ->setProject($this->getProject())
+      ->setContext($this->getContext())
+      ->setType($this->getType())
+      ->setName($this->getName());
+  }
+
+  public static function newFromDictionary(array $dictionary) {
+    $atom = id(new DivinerAtom())
+      ->setType(idx($dictionary, 'type'))
+      ->setName(idx($dictionary, 'name'))
+      ->setFile(idx($dictionary, 'file'))
+      ->setLine(idx($dictionary, 'line'))
+      ->setHash(idx($dictionary, 'hash'))
+      ->setLength(idx($dictionary, 'length'))
+      ->setContext(idx($dictionary, 'context'))
+      ->setLanguage(idx($dictionary, 'language'))
+      ->setParentHash(idx($dictionary, 'parentHash'))
+      ->setDocblockRaw(idx($dictionary, 'docblockRaw'));
+
+    foreach (idx($dictionary, 'warnings', array()) as $warning) {
+      $atom->addWarning($warning);
+    }
+
+    foreach (idx($dictionary, 'childHashes', array()) as $child) {
+      $atom->addChildHash($child);
+    }
+
+    return $atom;
+  }
+
+}
diff --git a/src/applications/diviner/atom/DivinerAtomRef.php b/src/applications/diviner/atom/DivinerAtomRef.php
new file mode 100644
index 0000000000..0ee5188c8c
--- /dev/null
+++ b/src/applications/diviner/atom/DivinerAtomRef.php
@@ -0,0 +1,69 @@
+<?php
+
+final class DivinerAtomRef {
+
+  private $project;
+  private $context;
+  private $type;
+  private $name;
+
+  public function setName($name) {
+    $this->name = $name;
+    return $this;
+  }
+
+  public function getName() {
+    return $this->name;
+  }
+
+  public function setType($type) {
+    $this->type = $type;
+    return $this;
+  }
+
+  public function getType() {
+    return $this->type;
+  }
+
+  public function setContext($context) {
+    $this->context = $context;
+    return $this;
+  }
+
+  public function getContext() {
+    return $this->context;
+  }
+
+  public function setProject($project) {
+    $this->project = $project;
+    return $this;
+  }
+
+  public function getProject() {
+    return $this->project;
+  }
+
+  public function toDictionary() {
+    return array(
+      'project' => $this->getProject(),
+      'context' => $this->getContext(),
+      'type'    => $this->getType(),
+      'name'    => $this->getName(),
+    );
+  }
+
+  public function toHash() {
+    $dict = $this->toDictionary();
+    ksort($dict);
+    return md5(serialize($dict)).'S';
+  }
+
+  public static function newFromDictionary(array $dict) {
+    $obj = new DivinerAtomRef();
+    $obj->project = idx($dict, 'project');
+    $obj->context = idx($dict, 'context');
+    $obj->type = idx($dict, 'type');
+    $obj->name = idx($dict, 'name');
+    return $obj;
+  }
+}
diff --git a/src/applications/diviner/atomizer/DivinerArticleAtomizer.php b/src/applications/diviner/atomizer/DivinerArticleAtomizer.php
new file mode 100644
index 0000000000..3718319219
--- /dev/null
+++ b/src/applications/diviner/atomizer/DivinerArticleAtomizer.php
@@ -0,0 +1,25 @@
+<?php
+
+final class DivinerArticleAtomizer extends DivinerAtomizer {
+
+  public function atomize($file_name, $file_data) {
+    $atom = $this->newAtom(DivinerAtom::TYPE_ARTICLE)
+      ->setLine(1)
+      ->setLength(count(explode("\n", $file_data)))
+      ->setLanguage('human');
+
+    $block = "/**\n".str_replace("\n", "\n * ", $file_data)."\n */";
+    $atom->setDocblockRaw($block);
+
+    $meta = $atom->getDocblockMeta();
+    $title = idx($meta, 'title');
+    if (!strlen($title)) {
+      $title = 'Untitled Article "'.basename($file_name).'"';
+      $atom->addWarning("Article has no @title!");
+    }
+    $atom->setName($title);
+
+    return array($atom);
+  }
+
+}
diff --git a/src/applications/diviner/atomizer/DivinerAtomizer.php b/src/applications/diviner/atomizer/DivinerAtomizer.php
new file mode 100644
index 0000000000..ba53c8cf4d
--- /dev/null
+++ b/src/applications/diviner/atomizer/DivinerAtomizer.php
@@ -0,0 +1,45 @@
+<?php
+
+/**
+ * Generate @{class:DivinerAtom}s from source code.
+ */
+abstract class DivinerAtomizer {
+
+  private $project;
+
+  /**
+   * If you make a significant change to an atomizer, you can bump this
+   * version to drop all the old atom caches.
+   */
+  public static function getAtomizerVersion() {
+    return 1;
+  }
+
+  abstract public function atomize($file_name, $file_data);
+
+  final public function setProject($project) {
+    $this->project = $project;
+    return $this;
+  }
+
+  final public function getProject() {
+    return $this->project;
+  }
+
+  protected function newAtom($type) {
+    return id(new DivinerAtom())
+      ->setProject($this->getProject())
+      ->setType($type);
+  }
+
+  protected function newRef($type, $name, $project = null, $context = null) {
+    $project = coalesce($project, $this->getProject());
+
+    return id(new DivinerAtomRef())
+      ->setProject($project)
+      ->setContext($context)
+      ->setType($type)
+      ->setName($name);
+  }
+
+}
diff --git a/src/applications/diviner/atomizer/DivinerFileAtomizer.php b/src/applications/diviner/atomizer/DivinerFileAtomizer.php
new file mode 100644
index 0000000000..3ea1ded7d6
--- /dev/null
+++ b/src/applications/diviner/atomizer/DivinerFileAtomizer.php
@@ -0,0 +1,14 @@
+<?php
+
+final class DivinerFileAtomizer extends DivinerAtomizer {
+
+  public function atomize($file_name, $file_data) {
+    $atom = $this->newAtom(DivinerAtom::TYPE_FILE)
+      ->setName($file_name)
+      ->setFile($file_name)
+      ->setContentRaw($file_data);
+
+    return array($atom);
+  }
+
+}
diff --git a/src/applications/diviner/cache/DivinerAtomCache.php b/src/applications/diviner/cache/DivinerAtomCache.php
new file mode 100644
index 0000000000..382c977e56
--- /dev/null
+++ b/src/applications/diviner/cache/DivinerAtomCache.php
@@ -0,0 +1,261 @@
+<?php
+
+final class DivinerAtomCache {
+
+  private $cache;
+
+  private $fileHashMap;
+  private $atomMap;
+  private $symbolMap;
+  private $edgeSrcMap;
+  private $edgeDstMap;
+  private $graphMap;
+
+  private $atoms = array();
+  private $writeAtoms = array();
+
+  public function __construct($cache_directory) {
+    $dir_cache = id(new PhutilKeyValueCacheDirectory())
+      ->setCacheDirectory($cache_directory);
+    $profiled_cache = id(new PhutilKeyValueCacheProfiler($dir_cache))
+      ->setProfiler(PhutilServiceProfiler::getInstance())
+      ->setName('diviner-atom-cache');
+    $this->cache = $profiled_cache;
+  }
+
+  private function getCache() {
+    return $this->cache;
+  }
+
+  public function delete() {
+    $this->getCache()->destroyCache();
+    $this->fileHashMap = null;
+    $this->atomMap = null;
+    $this->atoms = array();
+
+    return $this;
+  }
+
+  /**
+   * Convert a long-form hash key like `ccbbaaaaaaaaaaaaaaaaaaaaaaaaaaaaN` into
+   * a shortened directory form, like `cc/bb/aaaaaaaaN`. In conjunction with
+   * @{class:PhutilKeyValueCacheDirectory}, this gives us nice directories
+   * inside .divinercache instead of a million hash files with huge names at
+   * top level.
+   */
+  private function getHashKey($hash) {
+    return implode(
+      '/',
+      array(
+        substr($hash, 0, 2),
+        substr($hash, 2, 2),
+        substr($hash, 4, 8),
+      ));
+  }
+
+
+/* -(  File Hash Map  )------------------------------------------------------ */
+
+
+  public function getFileHashMap() {
+    if ($this->fileHashMap === null) {
+      $this->fileHashMap = $this->getCache()->getKey('file', array());
+    }
+    return $this->fileHashMap;
+  }
+
+  public function addFileHash($file_hash, $atom_hash) {
+    $this->getFileHashMap();
+    $this->fileHashMap[$file_hash] = $atom_hash;
+    return $this;
+  }
+
+  public function fileHashExists($file_hash) {
+    $map = $this->getFileHashMap();
+    return isset($map[$file_hash]);
+  }
+
+  public function deleteFileHash($file_hash) {
+    if ($this->fileHashExists($file_hash)) {
+      $map = $this->getFileHashMap();
+      $atom_hash = $map[$file_hash];
+      unset($this->fileHashMap[$file_hash]);
+
+      $this->deleteAtomHash($atom_hash);
+    }
+
+    return $this;
+  }
+
+
+/* -(  Atom Map  )----------------------------------------------------------- */
+
+
+  public function getAtomMap() {
+    if ($this->atomMap === null) {
+      $this->atomMap = $this->getCache()->getKey('atom', array());
+    }
+    return $this->atomMap;
+  }
+
+  public function getAtom($atom_hash) {
+    if (!array_key_exists($atom_hash, $this->atoms)) {
+      $key = 'atom/'.$this->getHashKey($atom_hash);
+      $this->atoms[$atom_hash] = $this->getCache()->getKey($key);
+    }
+    return $this->atoms[$atom_hash];
+  }
+
+  public function addAtom(array $atom) {
+    $hash = $atom['hash'];
+    $this->atoms[$hash] = $atom;
+
+    $this->getAtomMap();
+    $this->atomMap[$hash] = true;
+
+    $this->writeAtoms['atom/'.$this->getHashKey($hash)] = $atom;
+
+    return $this;
+  }
+
+  public function deleteAtomHash($atom_hash) {
+    $atom = $this->getAtom($atom_hash);
+    if ($atom) {
+      foreach ($atom['childHashes'] as $child_hash) {
+        $this->deleteAtomHash($child_hash);
+      }
+    }
+
+    $this->getAtomMap();
+    unset($this->atomMap[$atom_hash]);
+    unset($this->writeAtoms[$atom_hash]);
+
+    $this->getCache()->deleteKey('atom/'.$this->getHashKey($atom_hash));
+
+    return $this;
+  }
+
+  public function saveAtoms() {
+    $this->getCache()->setKeys(
+      array(
+        'file'  => $this->getFileHashMap(),
+        'atom'  => $this->getAtomMap(),
+      ) + $this->writeAtoms);
+    $this->writeAtoms = array();
+    return $this;
+  }
+
+
+/* -(  Symbol Hash Map  )---------------------------------------------------- */
+
+
+  public function getSymbolMap() {
+    if ($this->symbolMap === null) {
+      $this->symbolMap = $this->getCache()->getKey('symbol', array());
+    }
+    return $this->symbolMap;
+  }
+
+  public function addSymbol($atom_hash, $symbol_hash) {
+    $this->getSymbolMap();
+    $this->symbolMap[$atom_hash] = $symbol_hash;
+    return $this;
+  }
+
+  public function deleteSymbol($atom_hash) {
+    $this->getSymbolMap();
+    unset($this->symbolMap[$atom_hash]);
+
+    return $this;
+  }
+
+  public function saveSymbols() {
+    $this->getCache()->setKeys(
+      array(
+        'symbol' => $this->getSymbolMap(),
+      ));
+    return $this;
+  }
+
+/* -(  Edge Map  )----------------------------------------------------------- */
+
+
+  public function getEdgeMap() {
+    if ($this->edgeDstMap === null) {
+      $this->edgeDstMap = $this->getCache()->getKey('edge', array());
+      $this->edgeSrcMap = array();
+      foreach ($this->edgeDstMap as $dst => $srcs) {
+        foreach ($srcs as $src => $ignored) {
+          $this->edgeSrcMap[$src][$dst] = true;
+        }
+      }
+    }
+    return $this->edgeDstMap;
+  }
+
+  public function getEdgesWithDestination($symbol_hash) {
+    $this->getEdgeMap();
+    return array_keys(idx($this->edgeDstMap, $symbol_hash, array()));
+  }
+
+  public function addEdges($node_hash, array $symbol_hash_list) {
+    $this->getEdgeMap();
+    $this->edgeSrcMap[$node_hash] = array_fill_keys($symbol_hash_list, true);
+    foreach ($symbol_hash_list as $symbol_hash) {
+      $this->edgeDstMap[$symbol_hash][$node_hash] = true;
+    }
+    return $this;
+  }
+
+  public function deleteEdges($node_hash) {
+    $this->getEdgeMap();
+    foreach (idx($this->edgeSrcMap, $node_hash, array()) as $dst => $ignored) {
+      unset($this->edgeDstMap[$dst][$node_hash]);
+      if (empty($this->edgeDstMap[$dst])) {
+        unset($this->edgeDstMap[$dst]);
+      }
+    }
+    unset($this->edgeSrcMap[$node_hash]);
+    return $this;
+  }
+
+  public function saveEdges() {
+    $this->getCache()->setKeys(
+      array(
+        'edge' => $this->getEdgeMap(),
+      ));
+    return $this;
+  }
+
+
+/* -(  Graph Map  )---------------------------------------------------------- */
+
+
+  public function getGraphMap() {
+    if ($this->graphMap === null) {
+      $this->graphMap = $this->getCache()->getKey('graph', array());
+    }
+    return $this->graphMap;
+  }
+
+  public function deleteGraph($node_hash) {
+    $this->getGraphMap();
+    unset($this->graphMap[$node_hash]);
+    return $this;
+  }
+
+  public function addGraph($node_hash, $graph_hash) {
+    $this->getGraphMap();
+    $this->graphMap[$node_hash] = $graph_hash;
+    return $this;
+  }
+
+  public function saveGraph() {
+    $this->getCache()->setKeys(
+      array(
+        'graph' => $this->getGraphMap(),
+      ));
+    return $this;
+  }
+
+}
diff --git a/src/applications/diviner/workflow/DivinerAtomizeWorkflow.php b/src/applications/diviner/workflow/DivinerAtomizeWorkflow.php
new file mode 100644
index 0000000000..74130e7a73
--- /dev/null
+++ b/src/applications/diviner/workflow/DivinerAtomizeWorkflow.php
@@ -0,0 +1,103 @@
+<?php
+
+final class DivinerAtomizeWorkflow extends DivinerWorkflow {
+
+  public function didConstruct() {
+    $this
+      ->setName('atomize')
+      ->setSynopsis(pht('Build atoms from source.'))
+      ->setArguments(
+        array(
+          array(
+            'name'      => 'atomizer',
+            'param'     => 'class',
+            'help'      => 'Specify a subclass of DivinerAtomizer.',
+          ),
+          array(
+            'name'      => 'files',
+            'wildcard'  => true,
+          ),
+          array(
+            'name'      => 'ugly',
+            'help'      => 'Produce ugly (but faster) output.',
+          ),
+        ));
+  }
+
+  public function execute(PhutilArgumentParser $args) {
+    $console = PhutilConsole::getConsole();
+
+    $atomizer_class = $args->getArg('atomizer');
+    if (!$atomizer_class) {
+      throw new Exception("Specify an atomizer class with --atomizer.");
+    }
+
+    $symbols = id(new PhutilSymbolLoader())
+      ->setName($atomizer_class)
+      ->setConcreteOnly(true)
+      ->setAncestorClass('DivinerAtomizer')
+      ->selectAndLoadSymbols();
+    if (!$symbols) {
+      throw new Exception(
+        "Atomizer class '{$atomizer_class}' must be a concrete subclass of ".
+        "DivinerAtomizer.");
+    }
+
+    $atomizer = newv($atomizer_class, array());
+
+    $files = $args->getArg('files');
+    if (!$files) {
+      throw new Exception("Specify one or more files to atomize.");
+    }
+
+    $file_atomizer = new DivinerFileAtomizer();
+
+    $all_atoms = array();
+    foreach ($files as $file) {
+      $data = Filesystem::readFile($file);
+
+      if (!$this->shouldAtomizeFile($file, $data)) {
+        $console->writeLog("Skipping %s...\n", $file);
+        continue;
+      } else {
+        $console->writeLog("Atomizing %s...\n", $file);
+      }
+
+      $file_atoms = $file_atomizer->atomize($file, $data);
+      $all_atoms[] = $file_atoms;
+
+      if (count($file_atoms) !== 1) {
+        throw new Exception("Expected exactly one atom from file atomizer.");
+      }
+      $file_atom = head($file_atoms);
+
+      $atoms = $atomizer->atomize($file, $data);
+
+      foreach ($atoms as $atom) {
+        $file_atom->addChild($atom);
+      }
+
+      $all_atoms[] = $atoms;
+    }
+
+    $all_atoms = array_mergev($all_atoms);
+    $all_atoms = mpull($all_atoms, 'toDictionary');
+    $all_atoms = ipull($all_atoms, null, 'hash');
+
+    if ($args->getArg('ugly')) {
+      $json = json_encode($all_atoms);
+    } else {
+      $json_encoder = new PhutilJSON();
+      $json = $json_encoder->encodeFormatted($all_atoms);
+    }
+
+    $console->writeOut('%s', $json);
+
+    return 0;
+  }
+
+  private function shouldAtomizeFile($file_name, $file_data) {
+    return (strpos($file_data, '@'.'undivinable') === false);
+  }
+
+}
diff --git a/src/applications/diviner/workflow/DivinerGenerateWorkflow.php b/src/applications/diviner/workflow/DivinerGenerateWorkflow.php
new file mode 100644
index 0000000000..d2b88321c5
--- /dev/null
+++ b/src/applications/diviner/workflow/DivinerGenerateWorkflow.php
@@ -0,0 +1,384 @@
+<?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';
+  }
+
+}
diff --git a/src/applications/diviner/workflow/DivinerWorkflow.php b/src/applications/diviner/workflow/DivinerWorkflow.php
new file mode 100644
index 0000000000..81d9156957
--- /dev/null
+++ b/src/applications/diviner/workflow/DivinerWorkflow.php
@@ -0,0 +1,33 @@
+<?php
+
+abstract class DivinerWorkflow extends PhutilArgumentWorkflow {
+
+  private $atomCache;
+
+  public function isExecutable() {
+    return true;
+  }
+
+  protected function getRoot() {
+    return getcwd();
+  }
+
+  protected function getConfig($key, $default = null) {
+    return $default;
+  }
+
+  protected function getAtomCache() {
+    if (!$this->atomCache) {
+      $cache_directory = $this->getRoot().'/.divinercache';
+      $this->atomCache = new DivinerAtomCache($cache_directory);
+    }
+    return $this->atomCache;
+  }
+
+  protected function log($message) {
+    $console = PhutilConsole::getConsole();
+    $console->getServer()->setEnableLog(true);
+    $console->writeLog($message."\n");
+  }
+
+}