Support SVN pre-commit hoooks

Summary:
Ref T4189. This adds SVN support, which was a little more messy than I though. Principally, we can not use `PHABRICATOR_USER` for Subversion, because it strips away the entire environment for "security reasons".

Instead, use `--tunnel-user` plus `svnlook author` to figure out the author.

Also fix "ssh://" clone URIs, which needs to be "svn+ssh://".

Test Plan:
  - Made SVN commits through the hook.
  - Made Git commits, too, to make sure I didn't break anything.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T4189

Differential Revision: https://secure.phabricator.com/D7683

src/applications/diffusion/engine/DiffusionCommitHookEngine.php

@@ -5,6 +5,15 @@ final class DiffusionCommitHookEngine extends Phobject {
   private $viewer;
   private $repository;
   private $stdin;
+  private $subversionTransaction;
+  private $subversionRepository;
+
+
+  public function setSubversionTransactionInfo($transaction, $repository) {
+    $this->subversionTransaction = $transaction;
+    $this->subversionRepository = $repository;
+    return $this;
+  }
 
   public function setStdin($stdin) {
     $this->stdin = $stdin;
@@ -39,6 +48,9 @@ final class DiffusionCommitHookEngine extends Phobject {
       case PhabricatorRepositoryType::REPOSITORY_TYPE_GIT:
         $err = $this->executeGitHook();
         break;
+      case PhabricatorRepositoryType::REPOSITORY_TYPE_SVN:
+        $err = $this->executeSubversionHook();
+        break;
       default:
         throw new Exception(pht('Unsupported repository type "%s"!', $type));
     }
@@ -54,6 +66,13 @@ final class DiffusionCommitHookEngine extends Phobject {
     return 0;
   }
 
+  private function executeSubversionHook() {
+
+    // TODO: Do useful things here, too.
+
+    return 0;
+  }
+
   private function parseGitUpdates($stdin) {
     $updates = array();