Add support for partially uploaded files

Summary:
Ref T7149. This flags allocated but incomplete files and doesn't explode when trying to download them.

Files are marked complete when the last chunk is uploaded.

I added a key on `<authorPHID, isPartial>` so we can show you a list of partially uploaded files and prompt you to resume them at some point down the road.

Test Plan: Massaged debugging settings and uploaded README.md very slowly in 32b chunks. Saw the file lose its "Partial" flag when the last chunk finished.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: joshuaspence, epriestley

Maniphest Tasks: T7149

Differential Revision: https://secure.phabricator.com/D12063

src/applications/files/controller/PhabricatorFileInfoController.php

@@ -52,11 +52,21 @@ final class PhabricatorFileInfoController extends PhabricatorFileController {
     $ttl = $file->getTTL();
     if ($ttl !== null) {
       $ttl_tag = id(new PHUITagView())
-        ->setType(PHUITagView::TYPE_OBJECT)
+        ->setType(PHUITagView::TYPE_STATE)
+        ->setBackgroundColor(PHUITagView::COLOR_YELLOW)
         ->setName(pht('Temporary'));
       $header->addTag($ttl_tag);
     }
 
+    $partial = $file->getIsPartial();
+    if ($partial) {
+      $partial_tag = id(new PHUITagView())
+        ->setType(PHUITagView::TYPE_STATE)
+        ->setBackgroundColor(PHUITagView::COLOR_ORANGE)
+        ->setName(pht('Partial Upload'));
+      $header->addTag($partial_tag);
+    }
+
     $actions = $this->buildActionView($file);
     $timeline = $this->buildTransactionView($file);
     $crumbs = $this->buildApplicationCrumbs();
@@ -126,21 +136,27 @@ final class PhabricatorFileInfoController extends PhabricatorFileController {
       ->setObjectURI($this->getRequest()->getRequestURI())
       ->setObject($file);
 
+    $can_download = !$file->getIsPartial();
+
     if ($file->isViewableInBrowser()) {
       $view->addAction(
         id(new PhabricatorActionView())
           ->setName(pht('View File'))
           ->setIcon('fa-file-o')
-          ->setHref($file->getViewURI()));
+          ->setHref($file->getViewURI())
+          ->setDisabled(!$can_download)
+          ->setWorkflow(!$can_download));
     } else {
       $view->addAction(
         id(new PhabricatorActionView())
           ->setUser($viewer)
-          ->setRenderAsForm(true)
-          ->setDownload(true)
+          ->setRenderAsForm($can_download)
+          ->setDownload($can_download)
           ->setName(pht('Download File'))
           ->setIcon('fa-download')
-          ->setHref($file->getViewURI()));
+          ->setHref($file->getViewURI())
+          ->setDisabled(!$can_download)
+          ->setWorkflow(!$can_download));
     }
 
     $view->addAction(