Basic filename search support for Diffusion

Summary:
Ref T156. Adds basic filename search support for Diffusion,
currently only for Git repositories.

This is preliminary, and it's up for discussion:
  - is the UI in the right place;
  - what should the search query syntax be (e.g. whether
    to put `*`s in the beginning and end of it);
  - how to best approach it for Mercurial and/or SVN;
  - what's the cleanest result format for `lsquery` (I went
    for the minimum necessary change to `DiffusionBrowseSearchController`).

Test Plan:
Browse to a repository in Diffusion, and use both
`Search File Names` and `Search File Content`.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Maniphest Tasks: T156

Differential Revision: https://secure.phabricator.com/D8093

src/__phutil_library_map__.php

@@ -169,6 +169,7 @@ phutil_register_library_map(array(
     'ConduitAPI_diffusion_looksoon_Method' => 'applications/diffusion/conduit/ConduitAPI_diffusion_looksoon_Method.php',
     'ConduitAPI_diffusion_mergedcommitsquery_Method' => 'applications/diffusion/conduit/ConduitAPI_diffusion_mergedcommitsquery_Method.php',
     'ConduitAPI_diffusion_querycommits_Method' => 'applications/diffusion/conduit/ConduitAPI_diffusion_querycommits_Method.php',
+    'ConduitAPI_diffusion_querypaths_Method' => 'applications/diffusion/conduit/ConduitAPI_diffusion_querypaths_Method.php',
     'ConduitAPI_diffusion_rawdiffquery_Method' => 'applications/diffusion/conduit/ConduitAPI_diffusion_rawdiffquery_Method.php',
     'ConduitAPI_diffusion_readmequery_Method' => 'applications/diffusion/conduit/ConduitAPI_diffusion_readmequery_Method.php',
     'ConduitAPI_diffusion_refsquery_Method' => 'applications/diffusion/conduit/ConduitAPI_diffusion_refsquery_Method.php',
@@ -2657,6 +2658,7 @@ phutil_register_library_map(array(
     'ConduitAPI_diffusion_looksoon_Method' => 'ConduitAPI_diffusion_Method',
     'ConduitAPI_diffusion_mergedcommitsquery_Method' => 'ConduitAPI_diffusion_abstractquery_Method',
     'ConduitAPI_diffusion_querycommits_Method' => 'ConduitAPI_diffusion_Method',
+    'ConduitAPI_diffusion_querypaths_Method' => 'ConduitAPI_diffusion_abstractquery_Method',
     'ConduitAPI_diffusion_rawdiffquery_Method' => 'ConduitAPI_diffusion_abstractquery_Method',
     'ConduitAPI_diffusion_readmequery_Method' => 'ConduitAPI_diffusion_abstractquery_Method',
     'ConduitAPI_diffusion_refsquery_Method' => 'ConduitAPI_diffusion_abstractquery_Method',

src/applications/diffusion/conduit/ConduitAPI_diffusion_querypaths_Method.php

@@ -0,0 +1,87 @@
+<?php
+
+final class ConduitAPI_diffusion_querypaths_Method
+  extends ConduitAPI_diffusion_abstractquery_Method {
+
+  public function getMethodDescription() {
+    return pht('Filename search on a repository.');
+  }
+
+  public function defineReturnType() {
+    return 'list<string>';
+  }
+
+  protected function defineCustomParamTypes() {
+    return array(
+      'path' => 'required string',
+      'commit' => 'required string',
+      'pattern' => 'required string',
+      'limit' => 'optional int',
+      'offset' => 'optional int',
+    );
+  }
+
+  protected function getResult(ConduitAPIRequest $request) {
+    $results = parent::getResult($request);
+    $offset = $request->getValue('offset');
+    return array_slice($results, $offset);
+  }
+
+  protected function getGitResult(ConduitAPIRequest $request) {
+    $drequest = $this->getDiffusionRequest();
+    $path = $drequest->getPath();
+    $commit = $request->getValue('commit');
+    $repository = $drequest->getRepository();
+
+    // http://comments.gmane.org/gmane.comp.version-control.git/197735
+
+    $future = $repository->getLocalCommandFuture(
+      'ls-tree --name-only -r -z %s -- %s',
+      $commit,
+      $path);
+
+    $lines = id(new LinesOfALargeExecFuture($future))->setDelimiter("\0");
+    return $this->filterResults($lines, $request);
+  }
+
+  protected function getMercurialResult(ConduitAPIRequest $request) {
+    $drequest = $this->getDiffusionRequest();
+    $repository = $drequest->getRepository();
+    $path = $request->getValue('path');
+    $commit = $request->getValue('commit');
+
+    // Adapted from diffusion.browsequery.
+    list($entire_manifest) = $repository->execxLocalCommand(
+      'manifest --rev %s',
+      hgsprintf('%s', $commit));
+    $entire_manifest = explode("\n", $entire_manifest);
+
+    $match_against = trim($path, '/');
+    $match_len = strlen($match_against);
+
+    $lines = array();
+    foreach ($entire_manifest as $path) {
+      if (strlen($path) && !strncmp($path, $match_against, $match_len)) {
+        $lines[] = $path;
+      }
+    }
+    return $this->filterResults($lines, $request);
+  }
+
+  protected function filterResults($lines, ConduitAPIRequest $request) {
+    $pattern = $request->getValue('pattern');
+    $limit = $request->getValue('limit');
+    $offset = $request->getValue('offset');
+
+    $results = array();
+    foreach ($lines as $line) {
+      if (preg_match('#'.str_replace('#', '\#', $pattern).'#', $line)) {
+        $results[] = $line;
+        if (count($results) >= $offset + $limit) {
+          break;
+        }
+      }
+    }
+    return $results;
+  }
+}

src/applications/diffusion/controller/DiffusionBrowseController.php

@@ -26,8 +26,9 @@ abstract class DiffusionBrowseController extends DiffusionController {
               ->setValue($this->getRequest()->getStr('grep'))
               ->setCaption(pht('Enter a regular expression.')))
           ->appendChild(
-            id(new AphrontFormSubmitControl())
-              ->setValue(pht('Search File Content')));
+            id(new PHUIFormMultiSubmitControl())
+              ->addButton('__ls__', pht('Search File Names'))
+              ->addButton('__grep__', pht('Search File Content')));
         break;
     }
 

src/applications/diffusion/controller/DiffusionBrowseSearchController.php

@@ -53,16 +53,29 @@ final class DiffusionBrowseSearchController extends DiffusionBrowseController {
     $pager->setURI($this->getRequest()->getRequestURI(), 'page');
 
     try {
-
-      $results = $this->callConduitWithDiffusionRequest(
-        'diffusion.searchquery',
-        array(
-          'grep' => $this->getRequest()->getStr('grep'),
-          'stableCommitName' => $drequest->getStableCommitName(),
-          'path' => $drequest->getPath(),
-          'limit' => $limit + 1,
-          'offset' => $page));
-
+      if ($this->getRequest()->getStr('__grep__')) {
+        $results = $this->callConduitWithDiffusionRequest(
+          'diffusion.searchquery',
+          array(
+            'grep' => $this->getRequest()->getStr('grep'),
+            'stableCommitName' => $drequest->getStableCommitName(),
+            'path' => $drequest->getPath(),
+            'limit' => $limit + 1,
+            'offset' => $page));
+      } else { // Filename search.
+        $results_raw = $this->callConduitWithDiffusionRequest(
+          'diffusion.querypaths',
+          array(
+            'pattern' => $this->getRequest()->getStr('grep'),
+            'commit' => $drequest->getStableCommitName(),
+            'path' => $drequest->getPath(),
+            'limit' => $limit + 1,
+            'offset' => $page));
+        $results = [];
+        foreach ($results_raw as $result) {
+          $results[] = array($result, null, null);
+        }
+      }
     } catch (ConduitException $ex) {
       $err = $ex->getErrorDescription();
       if ($err != '') {

src/view/form/control/PHUIFormMultiSubmitControl.php

@@ -41,6 +41,7 @@ final class PHUIFormMultiSubmitControl extends AphrontFormControl {
         'class' => $class,
         'disabled' => $this->getDisabled() ? 'disabled' : null,
       ));
+    return $this;
   }
 
   protected function getCustomControlClass() {