Provide formal Users/Projects/Mailable fields for EditEngine

Summary: Ref T9132. This allows you to prefill EditEngine forms with stuff like `?subscribers=epriestley`, and we'll figure out what you mean.

Test Plan:
  - Did `/?subscribers=...` with various values (good, bad, mis-capitalized).
  - Did `/?projects=...` with various values (good, bad, mis-capitalized).
  - Reviewed documentation.
  - Reviewed {nav Config > HTTP Parameter Types}.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9132

Differential Revision: https://secure.phabricator.com/D14404

src/applications/phid/resolver/PhabricatorPHIDResolver.php

@@ -0,0 +1,46 @@
+<?php
+
+/**
+ * Resolve a list of identifiers into PHIDs.
+ *
+ * This class simplifies the process of convering a list of mixed token types
+ * (like some PHIDs and some usernames) into a list of just PHIDs.
+ */
+abstract class PhabricatorPHIDResolver extends Phobject {
+
+  private $viewer;
+
+  final public function setViewer(PhabricatorUser $viewer) {
+    $this->viewer = $viewer;
+    return $this;
+  }
+
+  final public function getViewer() {
+    return $this->viewer;
+  }
+
+  final public function resolvePHIDs(array $phids) {
+    $type_unknown = PhabricatorPHIDConstants::PHID_TYPE_UNKNOWN;
+
+    $names = array();
+    foreach ($phids as $key => $phid) {
+      if (phid_get_type($phid) == $type_unknown) {
+        $names[$key] = $phid;
+      }
+    }
+
+    if ($names) {
+      $map = $this->getResolutionMap($names);
+      foreach ($names as $key => $name) {
+        if (isset($map[$name])) {
+          $phids[$key] = $map[$name];
+        }
+      }
+    }
+
+    return $phids;
+  }
+
+  abstract protected function getResolutionMap(array $names);
+
+}

src/applications/phid/resolver/PhabricatorProjectPHIDResolver.php

@@ -0,0 +1,28 @@
+<?php
+
+final class PhabricatorProjectPHIDResolver
+  extends PhabricatorPHIDResolver {
+
+  protected function getResolutionMap(array $names) {
+    // This is a little awkward but we want to pick up the normalization
+    // rules from the PHIDType. This flow could perhaps be made cleaner.
+
+    foreach ($names as $key => $name) {
+      $names[$key] = '#'.$name;
+    }
+
+    $query = id(new PhabricatorObjectQuery())
+      ->setViewer($this->getViewer());
+
+    $projects = id(new PhabricatorProjectProjectPHIDType())
+      ->loadNamedObjects($query, $names);
+
+    $results = array();
+    foreach ($projects as $hashtag => $project) {
+      $results[substr($hashtag, 1)] = $project->getPHID();
+    }
+
+    return $results;
+  }
+
+}

src/applications/phid/resolver/PhabricatorUserPHIDResolver.php

@@ -0,0 +1,27 @@
+<?php
+
+final class PhabricatorUserPHIDResolver
+  extends PhabricatorPHIDResolver {
+
+  protected function getResolutionMap(array $names) {
+    // Pick up the normalization and case rules from the PHID type query.
+
+    foreach ($names as $key => $name) {
+      $names[$key] = '@'.$name;
+    }
+
+    $query = id(new PhabricatorObjectQuery())
+      ->setViewer($this->getViewer());
+
+    $users = id(new PhabricatorPeopleUserPHIDType())
+      ->loadNamedObjects($query, $names);
+
+    $results = array();
+    foreach ($users as $at_username => $user) {
+      $results[substr($at_username, 1)] = $user->getPHID();
+    }
+
+    return $results;
+  }
+
+}