Support branch offset/limit in Mercurial

Summary:
  - Support offset/limit as added by D2442, for Mercurial.
  - We just list everything and slice, no clear way to do better and this isn't a major perf issue.
  - No clear way to easily get by-update sorting, we can implement this by looking up revs if someone asks.
  - Bury some of the Git implementation details inside the Git query.

Test Plan:
  - Looked at a Git repo, clicked "View All Branches".
  - Looked at a Hg repo, clicked "View All Branches".
  - Limited page size to 1, made sure it limited properly.

Reviewers: aurelijus, btrahan, vrana

Reviewed By: aurelijus

CC: aran

Differential Revision: https://secure.phabricator.com/D2453

Author: epriestley

src/applications/diffusion/controller/branchtable/DiffusionBranchTableController.php

@@ -32,8 +32,7 @@ public function processRequest() {
     // TODO: Add support for branches that contain commit
     $query = DiffusionBranchQuery::newFromDiffusionRequest($drequest);
     $query->setOffset($pager->getOffset());
-    // we add 2 here, because of removed HEAD branch
-    $query->setLimit($pager->getPageSize() + 2);
+    $query->setLimit($pager->getPageSize() + 1);
     $branches = $query->loadBranches();
 
     $branches = $pager->sliceResults($branches);

src/applications/diffusion/controller/repository/DiffusionRepositoryController.php

@@ -154,8 +154,7 @@ private function buildBranchListTable(DiffusionRequest $drequest) {
       $limit = 15;
 
       $branch_query = DiffusionBranchQuery::newFromDiffusionRequest($drequest);
-      // we add 2 here, because of removed HEAD branch
-      $branch_query->setLimit($limit + 2);
+      $branch_query->setLimit($limit + 1);
       $branches = $branch_query->loadBranches();
 
       if (!$branches) {
@@ -182,20 +181,20 @@ private function buildBranchListTable(DiffusionRequest $drequest) {
       $panel->setHeader('Branches');
 
       if ($more_branches) {
-        $panel->setCaption('Showing the ' . $limit . ' most recent branches.');
+        $panel->setCaption('Showing ' . $limit . ' branches.');
       }
 
       $panel->addButton(
-          phutil_render_tag(
-              'a',
+        phutil_render_tag(
+          'a',
+          array(
+            'href' => $drequest->generateURI(
               array(
-                  'href' => $drequest->generateURI(
-                      array(
-                          'action' => 'branches',
-                      )),
-                  'class' => 'grey button',
-              ),
-              "Show All Branches \xC2\xBB"));
+                'action' => 'branches',
+              )),
+            'class' => 'grey button',
+          ),
+          "Show All Branches \xC2\xBB"));
 
       $panel->appendChild($table);
 

src/applications/diffusion/query/branch/git/DiffusionGitBranchQuery.php

@@ -21,7 +21,10 @@ final class DiffusionGitBranchQuery extends DiffusionBranchQuery {
   protected function executeQuery() {
     $drequest = $this->getRequest();
     $repository = $drequest->getRepository();
-    $count = $this->getOffset() + $this->getLimit();
+
+    // We need to add 1 in case we pick up HEAD.
+
+    $count = $this->getOffset() + $this->getLimit() + 1;
 
     list($stdout) = $repository->execxLocalCommand(
       'for-each-ref %C --sort=-creatordate --format=%s refs/remotes',
@@ -50,6 +53,13 @@ protected function executeQuery() {
       $branches = array_slice($branches, $offset);
     }
 
+    // We might have too many even after offset slicing, if there was no HEAD
+    // for some reason.
+    $limit = $this->getLimit();
+    if ($limit) {
+      $branches = array_slice($branches, 0, $limit);
+    }
+
     return $branches;
   }
 

src/applications/diffusion/query/branch/mercurial/DiffusionMercurialBranchQuery.php

@@ -1,7 +1,7 @@
 <?php
 
 /*
- * Copyright 2011 Facebook, Inc.
+ * Copyright 2012 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,7 +23,7 @@ protected function executeQuery() {
     $repository = $drequest->getRepository();
 
     list($stdout) = $repository->execxLocalCommand(
-      'branches');
+      '--debug branches');
     $branch_info = ArcanistMercurialParser::parseMercurialBranches($stdout);
 
     $branches = array();
@@ -34,6 +34,14 @@ protected function executeQuery() {
       $branches[] = $branch;
     }
 
+    if ($this->getOffset()) {
+      $branches = array_slice($branches, $this->getOffset());
+    }
+
+    if ($this->getLimit()) {
+      $branches = array_slice($branches, 0, $this->getLimit());
+    }
+
     return $branches;
   }