Teach Commit View about Encoding

Summary:
If the user specifies a text encoding via the "View Options" dropdown, respect this choice.
Ref Q68.

Test Plan: Play with the Encoding button in the view

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: tinloaf, speck, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Differential Revision: https://we.phorge.it/D25360

Author: avivey

src/applications/diffusion/conduit/DiffusionDiffQueryConduitAPIMethod.php

@@ -23,6 +23,7 @@ protected function defineCustomParamTypes() {
     return array(
       'path' => 'required string',
       'commit' => 'optional string',
+      'encoding' => 'optional string',
     );
   }
 
@@ -212,18 +213,20 @@ private function getGitOrMercurialResult(ConduitAPIRequest $request) {
       return $this->getEmptyResult();
     }
 
-    $parser = $this->getDefaultParser();
+    $parser = $this->getDefaultParser($request);
     $changes = $parser->parseDiff($raw_diff);
 
     return $changes;
   }
 
-  private function getDefaultParser() {
+  private function getDefaultParser(ConduitAPIRequest $request) {
     $drequest = $this->getDiffusionRequest();
     $repository = $drequest->getRepository();
 
     $parser = new ArcanistDiffParser();
-    $try_encoding = $repository->getDetail('encoding');
+    $try_encoding = coalesce(
+      $request->getValue('encoding'),
+      $repository->getDetail('encoding'));
     if ($try_encoding) {
       $parser->setTryEncoding($try_encoding);
     }

src/applications/diffusion/controller/DiffusionDiffController.php

@@ -48,6 +48,7 @@ public function handleRequest(AphrontRequest $request) {
       array(
         'commit' => $drequest->getCommit(),
         'path' => $drequest->getPath(),
+        'encoding' => $request->getStr('encoding'),
       ));
     $drequest->updateSymbolicCommit($data['effectiveCommit']);
     $raw_changes = ArcanistDiffChange::newFromConduit($data['changes']);