Store parents of forked pastes, and list child pastes if there are any.

Summary:
Added a 'parent' field which stores a PHID of another paste. If it is not NULL show a list of children pastes on view.
Also did some misc. refactoring to clean up the code a bit, specifically in the Create controller.

Test Plan:
- Checked old pastes, they were not affected.
- Added a paste, successfully.
- Forked it, successfully.
- Went to the original paste, saw the child paste listed.
- Forked it again, saw the new one added to the list.

Reviewers:
epriestley

CC:

Differential Revision: 672

resources/sql/patches/063.pasteforks.sql

@@ -0,0 +1,3 @@
+ALTER TABLE phabricator_pastebin.pastebin_paste
+  ADD COLUMN parentPHID VARCHAR(64) BINARY,
+  ADD KEY (parentPHID);

src/applications/paste/controller/create/PhabricatorPasteCreateController.php

@@ -27,19 +27,16 @@ class PhabricatorPasteCreateController extends PhabricatorPasteController {
     $error_view = null;
     $e_text = true;
 
+    $fork = $request->getInt('fork');
+
     $paste_text = null;
+    $paste_parent = null;
+
     if ($request->isFormPost()) {
       $errors = array();
       $title = $request->getStr('title');
 
-      $language = $request->getStr('language');
-      if ($language == 'infer') {
-        // If it's infer, store an empty string. Otherwise, store the
-        // language name. We do this so we can refer to 'infer' elsewhere
-        // in the code (such as default value) while retaining backwards
-        // compatibility with old posts with no language stored.
-        $language = '';
-      }
+      $paste_language = $request->getStr('language');
 
       $text = $request->getStr('text');
 
@@ -50,10 +47,26 @@ class PhabricatorPasteCreateController extends PhabricatorPasteController {
         $e_text = null;
       }
 
+      $parent = id(new PhabricatorPaste())->loadOneWhere(
+        'phid = %s',
+        $request->getStr('parent'));
+
+      if ($parent) {
+        $paste->setParentPHID($parent->getPHID());
+      }
+
       $paste->setTitle($title);
-      $paste->setLanguage($language);
 
       if (!$errors) {
+        if ($paste_language == 'infer') {
+          // If it's infer, store an empty string. Otherwise, store the
+          // language name. We do this so we can refer to 'infer' elsewhere
+          // in the code (such as default value) while retaining backwards
+          // compatibility with old posts with no language stored.
+          $paste_language = '';
+        }
+        $paste->setLanguage($paste_language);
+
         $paste_file = PhabricatorFile::newFromFileData(
           $text,
           array(
@@ -73,31 +86,26 @@ class PhabricatorPasteCreateController extends PhabricatorPasteController {
         $error_view->setTitle('A problem has occurred!');
       }
     } else {
-      $copy = $request->getInt('copy');
-      if ($copy) {
-        $copy_paste = id(new PhabricatorPaste())->load($copy);
-        if ($copy_paste) {
-          $title = nonempty($copy_paste->getTitle(), 'P'.$copy_paste->getID());
-          $paste->setTitle('Copy of '.$title);
-          $copy_file = id(new PhabricatorFile())->loadOneWhere(
+      if ($fork) {
+        $fork_paste = id(new PhabricatorPaste())->load($fork);
+        if ($fork_paste) {
+          $paste->setTitle('Fork of '.$fork_paste->getID().': '.
+            $fork_paste->getTitle());
+          $fork_file = id(new PhabricatorFile())->loadOneWhere(
             'phid = %s',
-            $copy_paste->getFilePHID());
-          $paste_text = $copy_file->loadFileData();
+            $fork_paste->getFilePHID());
+          $paste_text = $fork_file->loadFileData();
+          $paste_language = nonempty($fork_paste->getLanguage(), 'infer');
+          $paste_parent = $fork_paste->getPHID();
         }
+      } else {
+        $paste_language = PhabricatorEnv::getEnvConfig(
+          'pygments.dropdown-default');
       }
     }
 
     $form = new AphrontFormView();
 
-    // If we're coming back from an error and the language was already defined,
-    // use that. Otherwise, ask the config for the default.
-    if ($paste->getLanguage()) {
-      $language_default = $paste->getLanguage();
-    } else {
-      $language_default = PhabricatorEnv::getEnvConfig(
-        'pygments.dropdown-default');
-    }
-
     $available_languages = PhabricatorEnv::getEnvConfig(
       'pygments.dropdown-choices');
     asort($available_languages);
@@ -105,12 +113,13 @@ class PhabricatorPasteCreateController extends PhabricatorPasteController {
     $language_select = id(new AphrontFormSelectControl())
       ->setLabel('Language')
       ->setName('language')
-      ->setValue($language_default)
+      ->setValue($paste_language)
       ->setOptions($available_languages);
 
     $form
       ->setUser($user)
       ->setAction($request->getRequestURI()->getPath())
+      ->addHiddenInput('parent', $paste_parent)
       ->appendChild(
         id(new AphrontFormTextControl())
           ->setLabel('Title')
@@ -127,7 +136,7 @@ class PhabricatorPasteCreateController extends PhabricatorPasteController {
       ->appendChild(
         id(new AphrontFormSubmitControl())
           ->addCancelButton('/paste/')
-          ->setValue('Create Paste'));
+        ->setValue('Create Paste'));
 
     $panel = new AphrontPanelView();
     $panel->setWidth(AphrontPanelView::WIDTH_FORM);

src/applications/paste/controller/view/PhabricatorPasteViewController.php

@@ -42,7 +42,6 @@ class PhabricatorPasteViewController extends PhabricatorPasteController {
     }
 
     $corpus = $this->buildCorpus($paste, $file);
-
     $panel = new AphrontPanelView();
 
     if (strlen($paste->getTitle())) {
@@ -58,10 +57,10 @@ class PhabricatorPasteViewController extends PhabricatorPasteController {
       phutil_render_tag(
         'a',
         array(
-          'href' => '/paste/?copy='.$paste->getID(),
+          'href' => '/paste/?fork='.$paste->getID(),
           'class' => 'green button',
         ),
-        'Copy This'));
+        'Fork This'));
 
     $raw_uri = PhabricatorFileURI::getViewURIForPHID($paste->getFilePHID());
     $panel->addButton(
@@ -75,6 +74,37 @@ class PhabricatorPasteViewController extends PhabricatorPasteController {
 
     $panel->appendChild($corpus);
 
+    $forks_of_this_paste = id(new PhabricatorPaste())->loadAllWhere(
+      'parentPHID = %s',
+      $paste->getPHID());
+
+    if ($forks_of_this_paste) {
+      $forks = array();
+      foreach ($forks_of_this_paste as $fork) {
+        $forks[] = array(
+          $fork->getID(),
+          phutil_render_tag(
+            'a',
+            array(
+              'href' => '/P'.$fork->getID(),
+            ),
+            phutil_escape_html($fork->getTitle())
+          )
+        );
+      }
+
+      $forks_table = new AphrontTableView($forks);
+      $forks_table->setHeaders(
+        array(
+          'Paste ID',
+          'Title',
+        )
+      );
+
+      $panel->setHeader("Forks of this Paste");
+      $panel->appendChild($forks_table);
+    }
+
     return $this->buildStandardPageResponse(
       $panel,
       array(

src/applications/paste/controller/view/__init__.php

@@ -14,6 +14,7 @@ phutil_require_module('phabricator', 'applications/markup/syntax');
 phutil_require_module('phabricator', 'applications/paste/controller/base');
 phutil_require_module('phabricator', 'applications/paste/storage/paste');
 phutil_require_module('phabricator', 'infrastructure/celerity/api');
+phutil_require_module('phabricator', 'view/control/table');
 phutil_require_module('phabricator', 'view/layout/panel');
 
 phutil_require_module('phutil', 'markup');

src/applications/paste/storage/paste/PhabricatorPaste.php

@@ -23,6 +23,7 @@ class PhabricatorPaste extends PhabricatorPasteDAO {
   protected $authorPHID;
   protected $filePHID;
   protected $language;
+  protected $parentPHID;
 
   public function getConfiguration() {
     return array(