Introduce some convenience methods for handle rendering

Summary:
So I don't have to copy/paste everything again.

Used them at places I could find with my limited `grep` skills.

Test Plan: Visited hovercards, revision and tasks. No crashes.

Reviewers: epriestley, btrahan, chad

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5592

src/__celerity_resource_map__.php

@@ -3043,7 +3043,7 @@ celerity_register_resource_map(array(
   ),
   'phabricator-hovercard' =>
   array(
-    'uri' => '/res/a6eafd28/rsrc/js/application/core/Hovercard.js',
+    'uri' => '/res/345f3fca/rsrc/js/application/core/Hovercard.js',
     'type' => 'js',
     'requires' =>
     array(

src/__phutil_library_map__.php

@@ -1720,6 +1720,8 @@ phutil_register_library_map(array(
     'celerity_generate_unique_node_id' => 'infrastructure/celerity/api.php',
     'celerity_get_resource_uri' => 'infrastructure/celerity/api.php',
     'celerity_register_resource_map' => 'infrastructure/celerity/map.php',
+    'implode_handle_links' => 'applications/phid/handle/view/render.php',
+    'implode_selected_handle_links' => 'applications/phid/handle/view/render.php',
     'javelin_render_tag' => 'infrastructure/javelin/markup.php',
     'javelin_tag' => 'infrastructure/javelin/markup.php',
     'phabricator_date' => 'view/viewutils.php',

src/applications/base/controller/PhabricatorController.php

@@ -278,12 +278,9 @@ abstract class PhabricatorController extends AphrontController {
       throw new Exception("Unknown handle list style '{$style}'!");
     }
 
-    $items = array();
-    foreach ($phids as $phid) {
-      $items[] = $this->getHandle($phid)->renderLink();
-    }
-
-    return phutil_implode_html($style_map[$style], $items);
+    return implode_selected_handle_links($style_map[$style],
+      $this->getLoadedHandles(),
+      $phids);
   }
 
   protected function buildApplicationMenu() {

src/applications/differential/field/specification/DifferentialFieldSpecification.php

@@ -277,13 +277,8 @@ abstract class DifferentialFieldSpecification {
       return phutil_tag('em', array(), pht('None'));
     }
 
-    $links = array();
-    foreach ($user_phids as $user_phid) {
-      $handle = $this->getHandle($user_phid);
-      $links[] = $handle->renderLink();
-    }
-
-    return phutil_implode_html(', ', $links);
+    return implode_selected_handle_links(', ',
+      $this->getLoadedHandles(), $user_phids);
   }
 
 
@@ -988,6 +983,14 @@ abstract class DifferentialFieldSpecification {
     return $this->handles[$phid];
   }
 
+  final protected function getLoadedHandles() {
+    if ($this->handles === null) {
+      throw new DifferentialFieldDataNotAvailableException($this);
+    }
+
+    return $this->handles;
+  }
+
   /**
    * Get the list of properties for a diff set by @{method:setManualDiff}.
    *

src/applications/maniphest/event/ManiphestHovercardEventListener.php

@@ -60,7 +60,7 @@ final class ManiphestHovercardEventListener extends PhutilEventListener {
     $hovercard->addField(pht('Assigned to'), $owner);
     if ($project_phids) {
       $hovercard->addField(pht('Projects'),
-        $this->renderHandlesForPHIDs($project_phids, $viewer_handles));
+        implode_selected_handle_links(', ', $viewer_handles, $project_phids));
     }
 
     if ($edge_phids) {
@@ -84,9 +84,8 @@ final class ManiphestHovercardEventListener extends PhutilEventListener {
 
           $hovercard->addField(
             $edge_name,
-            $this->renderHandlesForPHIDs(
-              array_keys($edges[$edge_type]),
-              $viewer_handles)
+            implode_selected_handle_links(', ', $viewer_handles,
+              array_keys($edges[$edge_type]))
                 ->appendHTML($edge_overflow));
         }
       }
@@ -104,15 +103,4 @@ final class ManiphestHovercardEventListener extends PhutilEventListener {
       ->loadHandles();
   }
 
-  protected function renderHandlesForPHIDs(array $phids,
-    array $handles, $glue = ', ') {
-
-    $items = array();
-    foreach ($phids as $phid) {
-      $items[] = $handles[$phid]->renderLink();
-    }
-
-    return phutil_implode_html($glue, $items);
-  }
-
 }

src/applications/phid/handle/view/render.php

@@ -0,0 +1,35 @@
+<?php
+
+/**
+ * Implodes a list of handles, rendering their links
+ *
+ * @group  handle
+ * @return PhutilSafeHTML
+ */
+function implode_handle_links($glue, array $handles) {
+
+  $items = array();
+  foreach ($handles as $handle) {
+    $items[] = $handle->renderLink();
+  }
+
+  return phutil_implode_html($glue, $items);
+}
+
+/**
+ * Like @{function:implode_handle_links}Implodes selected handles from a pool of
+ * handles. Useful if you load handles for various phids, but only render a few
+ * of them at a time
+ *
+ * @group  handle
+ * @return PhutilSafeHTML
+ */
+function implode_selected_handle_links($glue, array $handles, array $phids) {
+
+  $items = array();
+  foreach ($phids as $phid) {
+    $items[] = $handles[$phid]->renderLink();
+  }
+
+  return phutil_implode_html($glue, $items);
+}