Converted Paste language selection to a typeahead

Summary: Fixes T11532. The language selection for pastes is now a typeahead that is backed by `pygments.dropdown-choices`. There is still a bit of weirdness around making "auto-detection" the default state. To actually select a different language, you first need to remove the "auto detect" option that is pre-populated in a new paste. Other than that, it works as intended.

Test Plan:
Create a new paste with a file extension that can be auto-detected.
Created a new paste and manually selected the language
Edited a paste and changed the language.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley, yelirekim

Maniphest Tasks: T11532

Differential Revision: https://secure.phabricator.com/D16463

resources/sql/autopatches/20160829.pastebin.01.language.sql

@@ -0,0 +1,3 @@
+/* Allow this column to be nullable (null means we'll try to autodetect) */
+ALTER TABLE {$NAMESPACE}_pastebin.pastebin_paste MODIFY language VARCHAR(64)
+    COLLATE {$COLLATE_TEXT};

resources/sql/autopatches/20160829.pastebin.02.language.sql

@@ -0,0 +1,2 @@
+UPDATE {$NAMESPACE}_pastebin.pastebin_paste SET language = NULL
+    WHERE language = '';

src/__phutil_library_map__.php

@@ -1732,6 +1732,7 @@ phutil_register_library_map(array(
     'PasteEditConduitAPIMethod' => 'applications/paste/conduit/PasteEditConduitAPIMethod.php',
     'PasteEmbedView' => 'applications/paste/view/PasteEmbedView.php',
     'PasteInfoConduitAPIMethod' => 'applications/paste/conduit/PasteInfoConduitAPIMethod.php',
+    'PasteLanguageSelectDatasource' => 'applications/paste/typeahead/PasteLanguageSelectDatasource.php',
     'PasteMailReceiver' => 'applications/paste/mail/PasteMailReceiver.php',
     'PasteQueryConduitAPIMethod' => 'applications/paste/conduit/PasteQueryConduitAPIMethod.php',
     'PasteReplyHandler' => 'applications/paste/mail/PasteReplyHandler.php',
@@ -6401,6 +6402,7 @@ phutil_register_library_map(array(
     'PasteEditConduitAPIMethod' => 'PhabricatorEditEngineAPIMethod',
     'PasteEmbedView' => 'AphrontView',
     'PasteInfoConduitAPIMethod' => 'PasteConduitAPIMethod',
+    'PasteLanguageSelectDatasource' => 'PhabricatorTypeaheadDatasource',
     'PasteMailReceiver' => 'PhabricatorObjectMailReceiver',
     'PasteQueryConduitAPIMethod' => 'PasteConduitAPIMethod',
     'PasteReplyHandler' => 'PhabricatorApplicationTransactionReplyHandler',

src/applications/paste/editor/PhabricatorPasteEditEngine.php

@@ -63,10 +63,6 @@ final class PhabricatorPasteEditEngine
   }
 
   protected function buildCustomEditFields($object) {
-    $langs = array(
-      '' => pht('(Detect From Filename in Title)'),
-    ) + PhabricatorEnv::getEnvConfig('pygments.dropdown-choices');
-
     return array(
       id(new PhabricatorTextEditField())
         ->setKey('title')
@@ -76,14 +72,14 @@ final class PhabricatorPasteEditEngine
         ->setConduitDescription(pht('Retitle the paste.'))
         ->setConduitTypeDescription(pht('New paste title.'))
         ->setValue($object->getTitle()),
-      id(new PhabricatorSelectEditField())
+      id(new PhabricatorDatasourceEditField())
         ->setKey('language')
         ->setLabel(pht('Language'))
         ->setTransactionType(
           PhabricatorPasteLanguageTransaction::TRANSACTIONTYPE)
         ->setAliases(array('lang'))
         ->setIsCopyable(true)
-        ->setOptions($langs)
+        ->setDatasource(new PasteLanguageSelectDatasource())
         ->setDescription(
           pht(
             'Language used for syntax highlighting. By default, inferred '.
@@ -91,7 +87,7 @@ final class PhabricatorPasteEditEngine
         ->setConduitDescription(
           pht('Change language used for syntax highlighting.'))
         ->setConduitTypeDescription(pht('New highlighting language.'))
-        ->setValue($object->getLanguage()),
+        ->setSingleValue($object->getLanguage()),
       id(new PhabricatorTextAreaEditField())
         ->setKey('text')
         ->setLabel(pht('Text'))

src/applications/paste/storage/PhabricatorPaste.php

@@ -42,7 +42,6 @@ final class PhabricatorPaste extends PhabricatorPasteDAO
 
     return id(new PhabricatorPaste())
       ->setTitle('')
-      ->setLanguage('')
       ->setStatus(self::STATUS_ACTIVE)
       ->setAuthorPHID($actor->getPHID())
       ->setViewPolicy($view_policy)
@@ -72,7 +71,7 @@ final class PhabricatorPaste extends PhabricatorPasteDAO
       self::CONFIG_COLUMN_SCHEMA => array(
         'status' => 'text32',
         'title' => 'text255',
-        'language' => 'text64',
+        'language' => 'text64?',
         'mailKey' => 'bytes20',
         'parentPHID' => 'phid?',
 

src/applications/paste/typeahead/PasteLanguageSelectDatasource.php

@@ -0,0 +1,42 @@
+<?php
+
+final class PasteLanguageSelectDatasource
+  extends PhabricatorTypeaheadDatasource {
+
+  public function getBrowseTitle() {
+    return pht('Browse Languages');
+  }
+
+  public function getPlaceholderText() {
+    return pht('Type a language name or leave blank to auto-detect...');
+  }
+
+  public function getDatasourceApplicationClass() {
+    return 'PhabricatorPasteApplication';
+  }
+
+  public function loadResults() {
+    $results = $this->buildResults();
+    return $this->filterResultsAgainstTokens($results);
+  }
+
+
+  protected function renderSpecialTokens(array $values) {
+    return $this->renderTokensFromResults($this->buildResults(), $values);
+  }
+
+  private function buildResults() {
+    $results = array();
+    $languages = PhabricatorEnv::getEnvConfig('pygments.dropdown-choices');
+
+    foreach ($languages as $value => $name) {
+      $result = id(new PhabricatorTypeaheadResult())
+        ->setPHID($value)
+        ->setName($name);
+
+      $results[$value] = $result;
+    }
+    return $results;
+  }
+
+}