Viewerize ArcBundle file loading callbacks

Summary: Ref T603. Clean these up and move them to a single place.

Test Plan:
  - Downloaded a raw diff.
  - Enabled "attach diffs", created a revision, got an email with a diff.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T603

Differential Revision: https://secure.phabricator.com/D7179

src/__phutil_library_map__.php

@@ -1185,6 +1185,7 @@ phutil_register_library_map(array(
     'PhabricatorFeedStoryStatus' => 'applications/feed/story/PhabricatorFeedStoryStatus.php',
     'PhabricatorFeedStoryTypeConstants' => 'applications/feed/constants/PhabricatorFeedStoryTypeConstants.php',
     'PhabricatorFile' => 'applications/files/storage/PhabricatorFile.php',
+    'PhabricatorFileBundleLoader' => 'applications/files/query/PhabricatorFileBundleLoader.php',
     'PhabricatorFileCommentController' => 'applications/files/controller/PhabricatorFileCommentController.php',
     'PhabricatorFileController' => 'applications/files/controller/PhabricatorFileController.php',
     'PhabricatorFileDAO' => 'applications/files/storage/PhabricatorFileDAO.php',

src/applications/differential/controller/DifferentialRevisionViewController.php

@@ -875,27 +875,6 @@ final class DifferentialRevisionViewController extends DifferentialController {
       ->appendChild($view);
   }
 
-  /**
-   * Straight copy of the loadFileByPhid method in
-   * @{class:DifferentialReviewRequestMail}.
-   *
-   * This is because of the code similarity between the buildPatch method in
-   * @{class:DifferentialReviewRequestMail} and @{method:buildRawDiffResponse}
-   * in this class. Both of these methods end up using call_user_func and this
-   * piece of code is the lucky function.
-   *
-   * @return mixed (@{class:PhabricatorFile} if found, null if not)
-   */
-  public function loadFileByPHID($phid) {
-    // TODO: (T603) Factor this and the other one out.
-    $file = id(new PhabricatorFile())->loadOneWhere(
-      'phid = %s',
-      $phid);
-    if (!$file) {
-      return null;
-    }
-    return $file->loadFileData();
-  }
 
   /**
    * Note this code is somewhat similar to the buildPatch method in
@@ -912,6 +891,8 @@ final class DifferentialRevisionViewController extends DifferentialController {
     assert_instances_of($changesets,    'DifferentialChangeset');
     assert_instances_of($vs_changesets, 'DifferentialChangeset');
 
+    $viewer = $this->getRequest()->getUser();
+
     $engine = new PhabricatorDifferenceEngine();
     $generated_changesets = array();
     foreach ($changesets as $changeset) {
@@ -954,9 +935,12 @@ final class DifferentialRevisionViewController extends DifferentialController {
     foreach ($raw_changes as $changedict) {
       $changes[] = ArcanistDiffChange::newFromDictionary($changedict);
     }
-    $bundle = ArcanistBundle::newFromChanges($changes);
 
-    $bundle->setLoadFileDataCallback(array($this, 'loadFileByPHID'));
+    $loader = id(new PhabricatorFileBundleLoader())
+      ->setViewer($viewer);
+
+    $bundle = ArcanistBundle::newFromChanges($changes);
+    $bundle->setLoadFileDataCallback(array($loader, 'loadFileData'));
 
     $vcs = $repository ? $repository->getVersionControlSystem() : null;
     switch ($vcs) {

src/applications/differential/mail/DifferentialReviewRequestMail.php

@@ -127,9 +127,15 @@ abstract class DifferentialReviewRequestMail extends DifferentialMail {
     foreach ($raw_changes as $changedict) {
       $changes[] = ArcanistDiffChange::newFromDictionary($changedict);
     }
-    $bundle = ArcanistBundle::newFromChanges($changes);
 
-    $bundle->setLoadFileDataCallback(array($this, 'loadFileByPHID'));
+    // TODO: It would be nice to have a real viewer here eventually, but
+    // in the meantime anyone we're sending mail to can certainly see the
+    // patch.
+    $loader = id(new PhabricatorFileBundleLoader())
+      ->setViewer(PhabricatorUser::getOmnipotentUser());
+
+    $bundle = ArcanistBundle::newFromChanges($changes);
+    $bundle->setLoadFileDataCallback(array($loader, 'loadFileData'));
 
     $format = PhabricatorEnv::getEnvConfig('metamta.differential.patch-format');
     switch ($format) {

src/applications/files/query/PhabricatorFileBundleLoader.php

@@ -0,0 +1,27 @@
+<?php
+
+/**
+ * Callback provider for loading @{class@arcanist:ArcanistBundle} file data
+ * stored in the Files application.
+ */
+final class PhabricatorFileBundleLoader {
+
+  private $viewer;
+
+  public function setViewer(PhabricatorUser $viewer) {
+    $this->viewer = $viewer;
+    return $this;
+  }
+
+  public function loadFileData($phid) {
+    $file = id(new PhabricatorFileQuery())
+      ->setViewer($this->viewer)
+      ->withPHIDs(array($phid))
+      ->executeOne();
+    if (!$file) {
+      return null;
+    }
+    return $file->loadFileData();
+  }
+
+}