Add a bin/hunks script to manage migrations of hunk data

Summary:
Ref T4045. Ref T5179. While we'll eventually need to force a migration, we can let installs (particularly large installs) do an online migration for now. This moves hunks to the new storage format one at a time.

(Note that nothing writes to the new store yet, so this is the only way to populate it.)

WARNING: Installs, don't run this yet! It won't compress the data. Wait until it can also do compression.

Test Plan: Added a `break;` after migrating one row and moved a few rows over. Spot checked them in the database and viewed the affected diffs.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T4045, T5179

Differential Revision: https://secure.phabricator.com/D9291

Author: epriestley

bin/hunks

@@ -0,0 +1 @@
+../scripts/setup/manage_hunks.php

scripts/setup/manage_hunks.php

@@ -0,0 +1,21 @@
+#!/usr/bin/env php
+<?php
+
+$root = dirname(dirname(dirname(__FILE__)));
+require_once $root.'/scripts/__init_script__.php';
+
+$args = new PhutilArgumentParser($argv);
+$args->setTagline('manage hunks');
+$args->setSynopsis(<<<EOSYNOPSIS
+**hunks** __command__ [__options__]
+    Manage Differential hunk storage.
+
+EOSYNOPSIS
+  );
+$args->parseStandardArguments();
+
+$workflows = id(new PhutilSymbolLoader())
+  ->setAncestorClass('PhabricatorHunksManagementWorkflow')
+  ->loadObjects();
+$workflows[] = new PhutilHelpArgumentWorkflow();
+$args->parseWorkflows($workflows);

src/__phutil_library_map__.php

@@ -1665,6 +1665,8 @@
     'PhabricatorHomeQuickCreateController' => 'applications/home/controller/PhabricatorHomeQuickCreateController.php',
     'PhabricatorHovercardExample' => 'applications/uiexample/examples/PhabricatorHovercardExample.php',
     'PhabricatorHovercardView' => 'view/widget/hovercard/PhabricatorHovercardView.php',
+    'PhabricatorHunksManagementMigrateWorkflow' => 'applications/differential/management/PhabricatorHunksManagementMigrateWorkflow.php',
+    'PhabricatorHunksManagementWorkflow' => 'applications/differential/management/PhabricatorHunksManagementWorkflow.php',
     'PhabricatorIRCBot' => 'infrastructure/daemon/bot/PhabricatorIRCBot.php',
     'PhabricatorIRCProtocolAdapter' => 'infrastructure/daemon/bot/adapter/PhabricatorIRCProtocolAdapter.php',
     'PhabricatorIRCProtocolHandler' => 'infrastructure/daemon/bot/handler/PhabricatorIRCProtocolHandler.php',
@@ -4488,6 +4490,8 @@
     'PhabricatorHomeQuickCreateController' => 'PhabricatorHomeController',
     'PhabricatorHovercardExample' => 'PhabricatorUIExample',
     'PhabricatorHovercardView' => 'AphrontView',
+    'PhabricatorHunksManagementMigrateWorkflow' => 'PhabricatorHunksManagementWorkflow',
+    'PhabricatorHunksManagementWorkflow' => 'PhabricatorManagementWorkflow',
     'PhabricatorIRCBot' => 'PhabricatorDaemon',
     'PhabricatorIRCProtocolAdapter' => 'PhabricatorBaseProtocolAdapter',
     'PhabricatorIRCProtocolHandler' => 'PhabricatorBotHandler',

src/applications/differential/management/PhabricatorHunksManagementMigrateWorkflow.php

@@ -0,0 +1,48 @@
+<?php
+
+final class PhabricatorHunksManagementMigrateWorkflow
+  extends PhabricatorHunksManagementWorkflow {
+
+  protected function didConstruct() {
+    $this
+      ->setName('migrate')
+      ->setExamples('**migrate**')
+      ->setSynopsis(pht('Migrate hunks to modern storage.'))
+      ->setArguments(array());
+  }
+
+  public function execute(PhutilArgumentParser $args) {
+    $saw_any_rows = false;
+    $console = PhutilConsole::getConsole();
+
+    $table = new DifferentialHunkLegacy();
+    foreach (new LiskMigrationIterator($table) as $hunk) {
+      $saw_any_rows = true;
+
+      $id = $hunk->getID();
+      $console->writeOut("%s\n", pht('Migrating hunk %d...', $id));
+
+      $new_hunk = id(new DifferentialHunkModern())
+        ->setChangesetID($hunk->getChangesetID())
+        ->setOldOffset($hunk->getOldOffset())
+        ->setOldLen($hunk->getOldLen())
+        ->setNewOffset($hunk->getNewOffset())
+        ->setNewLen($hunk->getNewLen())
+        ->setChanges($hunk->getChanges())
+        ->setDateCreated($hunk->getDateCreated())
+        ->setDateModified($hunk->getDateModified());
+
+      $hunk->openTransaction();
+        $new_hunk->save();
+        $hunk->delete();
+      $hunk->saveTransaction();
+    }
+
+    if ($saw_any_rows) {
+      $console->writeOut("%s\n", pht('Done.'));
+    } else {
+      $console->writeOut("%s\n", pht('No rows to migrate.'));
+    }
+  }
+
+}

src/applications/differential/management/PhabricatorHunksManagementWorkflow.php

@@ -0,0 +1,6 @@
+<?php
+
+abstract class PhabricatorHunksManagementWorkflow
+  extends PhabricatorManagementWorkflow {
+
+}

src/applications/differential/storage/DifferentialHunk.php

@@ -57,7 +57,7 @@ public function getContentWithMask($mask) {
 
   final private function makeContent($include) {
     $results = array();
-    $lines = explode("\n", $this->changes);
+    $lines = explode("\n", $this->getChanges());
 
     // NOTE: To determine whether the recomposed file should have a trailing
     // newline, we look for a "\ No newline at end of file" line which appears