Allow pastes to be edited

Summary: Permits the name and langauge of a paste to be edited. This will eventually allow the visibility policy to be edited as well.

Test Plan: Edited name/langauge of some pastes. Tried to edit a paste I didn't own, was harshly rebuffed.

Reviewers: vrana, btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T1690

Differential Revision: https://secure.phabricator.com/D3376

src/applications/paste/controller/PhabricatorPasteViewController.php

@@ -59,7 +59,7 @@ final class PhabricatorPasteViewController extends PhabricatorPasteController {
         $fork_phids));
 
     $header = $this->buildHeaderView($paste);
-    $actions = $this->buildActionView($paste, $file);
+    $actions = $this->buildActionView($user, $paste, $file);
     $properties = $this->buildPropertyView($paste, $fork_phids);
     $source_code = $this->buildSourceCodeView($paste, $file);
 
@@ -89,9 +89,15 @@ final class PhabricatorPasteViewController extends PhabricatorPasteController {
   }
 
   private function buildActionView(
+    PhabricatorUser $user,
     PhabricatorPaste $paste,
     PhabricatorFile $file) {
 
+    $can_edit = PhabricatorPolicyFilter::hasCapability(
+      $user,
+      $paste,
+      PhabricatorPolicyCapability::CAN_EDIT);
+
     return id(new PhabricatorActionListView())
       ->addAction(
         id(new PhabricatorActionView())
@@ -102,7 +108,14 @@ final class PhabricatorPasteViewController extends PhabricatorPasteController {
         id(new PhabricatorActionView())
           ->setName(pht('View Raw File'))
           ->setIcon('file')
-          ->setHref($file->getBestURI()));
+          ->setHref($file->getBestURI()))
+      ->addAction(
+        id(new PhabricatorActionView())
+          ->setName(pht('Edit Paste'))
+          ->setIcon('edit')
+          ->setDisabled(!$can_edit)
+          ->setWorkflow(!$can_edit)
+          ->setHref($this->getApplicationURI('/edit/'.$paste->getID().'/')));
   }
 
   private function buildPropertyView(