Restore viewer() function to "Responsible Users" tokenizer in Differential

Summary:
Ref T10939. This makes the `viewer()` function work again. It retains its own meaning (viewer, plus all their projects and packages).

There's no `exact-viewer()` function; we could conceivably add one eventually if we need it.

Test Plan:
  - Queried for `viewer()`, got the same results as querying by my own username.
  - Browsed function in token browser.
  - Reviewed autogenerated documentation.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10939

Differential Revision: https://secure.phabricator.com/D15951

src/__phutil_library_map__.php

@@ -495,6 +495,7 @@ phutil_register_library_map(array(
     'DifferentialRequiredSignaturesField' => 'applications/differential/customfield/DifferentialRequiredSignaturesField.php',
     'DifferentialResponsibleDatasource' => 'applications/differential/typeahead/DifferentialResponsibleDatasource.php',
     'DifferentialResponsibleUserDatasource' => 'applications/differential/typeahead/DifferentialResponsibleUserDatasource.php',
+    'DifferentialResponsibleViewerFunctionDatasource' => 'applications/differential/typeahead/DifferentialResponsibleViewerFunctionDatasource.php',
     'DifferentialRevertPlanField' => 'applications/differential/customfield/DifferentialRevertPlanField.php',
     'DifferentialReviewedByField' => 'applications/differential/customfield/DifferentialReviewedByField.php',
     'DifferentialReviewer' => 'applications/differential/storage/DifferentialReviewer.php',
@@ -4720,6 +4721,7 @@ phutil_register_library_map(array(
     'DifferentialRequiredSignaturesField' => 'DifferentialCoreCustomField',
     'DifferentialResponsibleDatasource' => 'PhabricatorTypeaheadCompositeDatasource',
     'DifferentialResponsibleUserDatasource' => 'PhabricatorTypeaheadCompositeDatasource',
+    'DifferentialResponsibleViewerFunctionDatasource' => 'PhabricatorTypeaheadDatasource',
     'DifferentialRevertPlanField' => 'DifferentialStoredCustomField',
     'DifferentialReviewedByField' => 'DifferentialCoreCustomField',
     'DifferentialReviewer' => 'Phobject',

src/applications/differential/typeahead/DifferentialResponsibleDatasource.php

@@ -18,10 +18,46 @@ final class DifferentialResponsibleDatasource
   public function getComponentDatasources() {
     return array(
       new DifferentialResponsibleUserDatasource(),
+      new DifferentialResponsibleViewerFunctionDatasource(),
       new DifferentialExactUserFunctionDatasource(),
       new PhabricatorProjectDatasource(),
       new PhabricatorOwnersPackageDatasource(),
     );
   }
 
+  public static function expandResponsibleUsers(
+    PhabricatorUser $viewer,
+    array $values) {
+
+    $phids = array();
+    foreach ($values as $value) {
+      if (phid_get_type($value) == PhabricatorPeopleUserPHIDType::TYPECONST) {
+        $phids[] = $value;
+      }
+    }
+
+    if (!$phids) {
+      return $values;
+    }
+
+    $projects = id(new PhabricatorProjectQuery())
+       ->setViewer($viewer)
+       ->withMemberPHIDs($phids)
+       ->execute();
+    foreach ($projects as $project) {
+      $phids[] = $project->getPHID();
+      $values[] = $project->getPHID();
+    }
+
+    $packages = id(new PhabricatorOwnersPackageQuery())
+      ->setViewer($viewer)
+      ->withOwnerPHIDs($phids)
+      ->execute();
+    foreach ($packages as $package) {
+      $values[] = $package->getPHID();
+    }
+
+    return $values;
+  }
+
 }

src/applications/differential/typeahead/DifferentialResponsibleUserDatasource.php

@@ -22,37 +22,9 @@ final class DifferentialResponsibleUserDatasource
   }
 
   protected function evaluateValues(array $values) {
-    $viewer = $this->getViewer();
-
-    $phids = array();
-    foreach ($values as $value) {
-      if (phid_get_type($value) == PhabricatorPeopleUserPHIDType::TYPECONST) {
-        $phids[] = $value;
-      }
-    }
-
-    if (!$phids) {
-      return $values;
-    }
-
-    $projects = id(new PhabricatorProjectQuery())
-       ->setViewer($viewer)
-       ->withMemberPHIDs($phids)
-       ->execute();
-    foreach ($projects as $project) {
-      $phids[] = $project->getPHID();
-      $values[] = $project->getPHID();
-    }
-
-    $packages = id(new PhabricatorOwnersPackageQuery())
-      ->setViewer($viewer)
-      ->withOwnerPHIDs($phids)
-      ->execute();
-    foreach ($packages as $package) {
-      $values[] = $package->getPHID();
-    }
-
-    return $values;
+    return DifferentialResponsibleDatasource::expandResponsibleUsers(
+      $this->getViewer(),
+      $values);
   }
 
 }

src/applications/differential/typeahead/DifferentialResponsibleViewerFunctionDatasource.php

@@ -0,0 +1,77 @@
+<?php
+
+final class DifferentialResponsibleViewerFunctionDatasource
+  extends PhabricatorTypeaheadDatasource {
+
+  public function getBrowseTitle() {
+    return pht('Browse Viewer');
+  }
+
+  public function getPlaceholderText() {
+    return pht('Type viewer()...');
+  }
+
+  public function getDatasourceApplicationClass() {
+    return 'PhabricatorPeopleApplication';
+  }
+
+  public function getDatasourceFunctions() {
+    return array(
+      'viewer' => array(
+        'name' => pht('Current Viewer'),
+        'summary' => pht('Use the current viewing user.'),
+        'description' => pht(
+          'Show revisions the current viewer is responsible for. This '.
+          'function inclues revisions the viewer is responsible for through '.
+          'membership in projects and packages.'),
+      ),
+    );
+  }
+
+  public function loadResults() {
+    if ($this->getViewer()->getPHID()) {
+      $results = array($this->renderViewerFunctionToken());
+    } else {
+      $results = array();
+    }
+
+    return $this->filterResultsAgainstTokens($results);
+  }
+
+  protected function canEvaluateFunction($function) {
+    if (!$this->getViewer()->getPHID()) {
+      return false;
+    }
+
+    return parent::canEvaluateFunction($function);
+  }
+
+  protected function evaluateFunction($function, array $argv_list) {
+    $results = array();
+    foreach ($argv_list as $argv) {
+      $results[] = $this->getViewer()->getPHID();
+    }
+
+    return DifferentialResponsibleDatasource::expandResponsibleUsers(
+      $this->getViewer(),
+      $results);
+  }
+
+  public function renderFunctionTokens($function, array $argv_list) {
+    $tokens = array();
+    foreach ($argv_list as $argv) {
+      $tokens[] = PhabricatorTypeaheadTokenView::newFromTypeaheadResult(
+        $this->renderViewerFunctionToken());
+    }
+    return $tokens;
+  }
+
+  private function renderViewerFunctionToken() {
+    return $this->newFunctionResult()
+      ->setName(pht('Current Viewer'))
+      ->setPHID('viewer()')
+      ->setIcon('fa-user')
+      ->setUnique(true);
+  }
+
+}