Update Legalpad to use modular transactions

Summary: Update Legalpad for modular transactions

Test Plan:
- New Document (no sign)
- New Document (individual)
- New Document (corp)
- Require Signature - get prompted to sign before I can do anything.
- Edit Documents
- Sign Documents
- Comment on Documents

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D17826

src/__phutil_library_map__.php

@@ -1400,8 +1400,10 @@ phutil_register_library_map(array(
     'LegalpadDocumentEditor' => 'applications/legalpad/editor/LegalpadDocumentEditor.php',
     'LegalpadDocumentListController' => 'applications/legalpad/controller/LegalpadDocumentListController.php',
     'LegalpadDocumentManageController' => 'applications/legalpad/controller/LegalpadDocumentManageController.php',
+    'LegalpadDocumentPreambleTransaction' => 'applications/legalpad/xaction/LegalpadDocumentPreambleTransaction.php',
     'LegalpadDocumentQuery' => 'applications/legalpad/query/LegalpadDocumentQuery.php',
     'LegalpadDocumentRemarkupRule' => 'applications/legalpad/remarkup/LegalpadDocumentRemarkupRule.php',
+    'LegalpadDocumentRequireSignatureTransaction' => 'applications/legalpad/xaction/LegalpadDocumentRequireSignatureTransaction.php',
     'LegalpadDocumentSearchEngine' => 'applications/legalpad/query/LegalpadDocumentSearchEngine.php',
     'LegalpadDocumentSignController' => 'applications/legalpad/controller/LegalpadDocumentSignController.php',
     'LegalpadDocumentSignature' => 'applications/legalpad/storage/LegalpadDocumentSignature.php',
@@ -1409,8 +1411,12 @@ phutil_register_library_map(array(
     'LegalpadDocumentSignatureListController' => 'applications/legalpad/controller/LegalpadDocumentSignatureListController.php',
     'LegalpadDocumentSignatureQuery' => 'applications/legalpad/query/LegalpadDocumentSignatureQuery.php',
     'LegalpadDocumentSignatureSearchEngine' => 'applications/legalpad/query/LegalpadDocumentSignatureSearchEngine.php',
+    'LegalpadDocumentSignatureTypeTransaction' => 'applications/legalpad/xaction/LegalpadDocumentSignatureTypeTransaction.php',
     'LegalpadDocumentSignatureVerificationController' => 'applications/legalpad/controller/LegalpadDocumentSignatureVerificationController.php',
     'LegalpadDocumentSignatureViewController' => 'applications/legalpad/controller/LegalpadDocumentSignatureViewController.php',
+    'LegalpadDocumentTextTransaction' => 'applications/legalpad/xaction/LegalpadDocumentTextTransaction.php',
+    'LegalpadDocumentTitleTransaction' => 'applications/legalpad/xaction/LegalpadDocumentTitleTransaction.php',
+    'LegalpadDocumentTransactionType' => 'applications/legalpad/xaction/LegalpadDocumentTransactionType.php',
     'LegalpadMailReceiver' => 'applications/legalpad/mail/LegalpadMailReceiver.php',
     'LegalpadObjectNeedsSignatureEdgeType' => 'applications/legalpad/edge/LegalpadObjectNeedsSignatureEdgeType.php',
     'LegalpadReplyHandler' => 'applications/legalpad/mail/LegalpadReplyHandler.php',
@@ -6395,8 +6401,10 @@ phutil_register_library_map(array(
     'LegalpadDocumentEditor' => 'PhabricatorApplicationTransactionEditor',
     'LegalpadDocumentListController' => 'LegalpadController',
     'LegalpadDocumentManageController' => 'LegalpadController',
+    'LegalpadDocumentPreambleTransaction' => 'LegalpadDocumentTransactionType',
     'LegalpadDocumentQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
     'LegalpadDocumentRemarkupRule' => 'PhabricatorObjectRemarkupRule',
+    'LegalpadDocumentRequireSignatureTransaction' => 'LegalpadDocumentTransactionType',
     'LegalpadDocumentSearchEngine' => 'PhabricatorApplicationSearchEngine',
     'LegalpadDocumentSignController' => 'LegalpadController',
     'LegalpadDocumentSignature' => array(
@@ -6407,15 +6415,19 @@ phutil_register_library_map(array(
     'LegalpadDocumentSignatureListController' => 'LegalpadController',
     'LegalpadDocumentSignatureQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
     'LegalpadDocumentSignatureSearchEngine' => 'PhabricatorApplicationSearchEngine',
+    'LegalpadDocumentSignatureTypeTransaction' => 'LegalpadDocumentTransactionType',
     'LegalpadDocumentSignatureVerificationController' => 'LegalpadController',
     'LegalpadDocumentSignatureViewController' => 'LegalpadController',
+    'LegalpadDocumentTextTransaction' => 'LegalpadDocumentTransactionType',
+    'LegalpadDocumentTitleTransaction' => 'LegalpadDocumentTransactionType',
+    'LegalpadDocumentTransactionType' => 'PhabricatorModularTransactionType',
     'LegalpadMailReceiver' => 'PhabricatorObjectMailReceiver',
     'LegalpadObjectNeedsSignatureEdgeType' => 'PhabricatorEdgeType',
     'LegalpadReplyHandler' => 'PhabricatorApplicationTransactionReplyHandler',
     'LegalpadRequireSignatureHeraldAction' => 'HeraldAction',
     'LegalpadSchemaSpec' => 'PhabricatorConfigSchemaSpec',
     'LegalpadSignatureNeededByObjectEdgeType' => 'PhabricatorEdgeType',
-    'LegalpadTransaction' => 'PhabricatorApplicationTransaction',
+    'LegalpadTransaction' => 'PhabricatorModularTransaction',
     'LegalpadTransactionComment' => 'PhabricatorApplicationTransactionComment',
     'LegalpadTransactionQuery' => 'PhabricatorApplicationTransactionQuery',
     'LegalpadTransactionView' => 'PhabricatorApplicationTransactionView',

src/applications/legalpad/controller/LegalpadDocumentEditController.php

@@ -57,7 +57,8 @@ final class LegalpadDocumentEditController extends LegalpadController {
         $errors[] = pht('The document title may not be blank.');
       } else {
         $xactions[] = id(new LegalpadTransaction())
-          ->setTransactionType(LegalpadTransaction::TYPE_TITLE)
+          ->setTransactionType(
+            LegalpadDocumentTitleTransaction::TRANSACTIONTYPE)
           ->setNewValue($title);
       }
 
@@ -67,7 +68,8 @@ final class LegalpadDocumentEditController extends LegalpadController {
         $errors[] = pht('The document may not be blank.');
       } else {
         $xactions[] = id(new LegalpadTransaction())
-          ->setTransactionType(LegalpadTransaction::TYPE_TEXT)
+          ->setTransactionType(
+            LegalpadDocumentTextTransaction::TRANSACTIONTYPE)
           ->setNewValue($text);
       }
 
@@ -83,13 +85,15 @@ final class LegalpadDocumentEditController extends LegalpadController {
       if ($is_create) {
         $v_signature_type = $request->getStr('signatureType');
         $xactions[] = id(new LegalpadTransaction())
-          ->setTransactionType(LegalpadTransaction::TYPE_SIGNATURE_TYPE)
+          ->setTransactionType(
+            LegalpadDocumentSignatureTypeTransaction::TRANSACTIONTYPE)
           ->setNewValue($v_signature_type);
       }
 
       $v_preamble = $request->getStr('preamble');
       $xactions[] = id(new LegalpadTransaction())
-        ->setTransactionType(LegalpadTransaction::TYPE_PREAMBLE)
+        ->setTransactionType(
+          LegalpadDocumentPreambleTransaction::TRANSACTIONTYPE)
         ->setNewValue($v_preamble);
 
       $v_require_signature = $request->getBool('requireSignature', 0);
@@ -106,7 +110,8 @@ final class LegalpadDocumentEditController extends LegalpadController {
       }
       if ($viewer->getIsAdmin()) {
         $xactions[] = id(new LegalpadTransaction())
-          ->setTransactionType(LegalpadTransaction::TYPE_REQUIRE_SIGNATURE)
+          ->setTransactionType(
+            LegalpadDocumentRequireSignatureTransaction::TRANSACTIONTYPE)
           ->setNewValue($v_require_signature);
       }
 

src/applications/legalpad/editor/LegalpadDocumentEditor.php

@@ -3,8 +3,6 @@
 final class LegalpadDocumentEditor
   extends PhabricatorApplicationTransactionEditor {
 
-  private $isContribution = false;
-
   public function getEditorApplicationClass() {
     return 'PhabricatorLegalpadApplication';
   }
@@ -13,15 +11,6 @@ final class LegalpadDocumentEditor
     return pht('Legalpad Documents');
   }
 
-  private function setIsContribution($is_contribution) {
-    $this->isContribution = $is_contribution;
-    return $this;
-  }
-
-  private function isContribution() {
-    return $this->isContribution;
-  }
-
   public function getTransactionTypes() {
     $types = parent::getTransactionTypes();
 
@@ -29,99 +18,25 @@ final class LegalpadDocumentEditor
     $types[] = PhabricatorTransactions::TYPE_VIEW_POLICY;
     $types[] = PhabricatorTransactions::TYPE_EDIT_POLICY;
 
-    $types[] = LegalpadTransaction::TYPE_TITLE;
-    $types[] = LegalpadTransaction::TYPE_TEXT;
-    $types[] = LegalpadTransaction::TYPE_SIGNATURE_TYPE;
-    $types[] = LegalpadTransaction::TYPE_PREAMBLE;
-    $types[] = LegalpadTransaction::TYPE_REQUIRE_SIGNATURE;
-
     return $types;
   }
 
-  protected function getCustomTransactionOldValue(
-    PhabricatorLiskDAO $object,
-    PhabricatorApplicationTransaction $xaction) {
-
-    switch ($xaction->getTransactionType()) {
-      case LegalpadTransaction::TYPE_TITLE:
-        return $object->getDocumentBody()->getTitle();
-      case LegalpadTransaction::TYPE_TEXT:
-        return $object->getDocumentBody()->getText();
-      case LegalpadTransaction::TYPE_SIGNATURE_TYPE:
-        return $object->getSignatureType();
-      case LegalpadTransaction::TYPE_PREAMBLE:
-        return $object->getPreamble();
-      case LegalpadTransaction::TYPE_REQUIRE_SIGNATURE:
-        return (bool)$object->getRequireSignature();
-    }
-  }
-
-  protected function getCustomTransactionNewValue(
-    PhabricatorLiskDAO $object,
-    PhabricatorApplicationTransaction $xaction) {
-
-    switch ($xaction->getTransactionType()) {
-      case LegalpadTransaction::TYPE_TITLE:
-      case LegalpadTransaction::TYPE_TEXT:
-      case LegalpadTransaction::TYPE_SIGNATURE_TYPE:
-      case LegalpadTransaction::TYPE_PREAMBLE:
-        return $xaction->getNewValue();
-      case LegalpadTransaction::TYPE_REQUIRE_SIGNATURE:
-        return (bool)$xaction->getNewValue();
-    }
-  }
-
-  protected function applyCustomInternalTransaction(
-    PhabricatorLiskDAO $object,
-    PhabricatorApplicationTransaction $xaction) {
-
-    switch ($xaction->getTransactionType()) {
-      case LegalpadTransaction::TYPE_TITLE:
-        $object->setTitle($xaction->getNewValue());
-        $body = $object->getDocumentBody();
-        $body->setTitle($xaction->getNewValue());
-        $this->setIsContribution(true);
-        break;
-      case LegalpadTransaction::TYPE_TEXT:
-        $body = $object->getDocumentBody();
-        $body->setText($xaction->getNewValue());
-        $this->setIsContribution(true);
-        break;
-      case LegalpadTransaction::TYPE_SIGNATURE_TYPE:
-        $object->setSignatureType($xaction->getNewValue());
-        break;
-      case LegalpadTransaction::TYPE_PREAMBLE:
-        $object->setPreamble($xaction->getNewValue());
-        break;
-      case LegalpadTransaction::TYPE_REQUIRE_SIGNATURE:
-        $object->setRequireSignature((int)$xaction->getNewValue());
-        break;
-    }
-  }
-
-  protected function applyCustomExternalTransaction(
-    PhabricatorLiskDAO $object,
-    PhabricatorApplicationTransaction $xaction) {
-
-    switch ($xaction->getTransactionType()) {
-      case LegalpadTransaction::TYPE_REQUIRE_SIGNATURE:
-        if ($xaction->getNewValue()) {
-          $session = new PhabricatorAuthSession();
-          queryfx(
-            $session->establishConnection('w'),
-            'UPDATE %T SET signedLegalpadDocuments = 0',
-            $session->getTableName());
-        }
-        break;
-    }
-    return;
-  }
-
   protected function applyFinalEffects(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
-    if ($this->isContribution()) {
+    $is_contribution = false;
+
+    foreach ($xactions as $xaction) {
+      switch ($xaction->getTransactionType()) {
+        case LegalpadDocumentTitleTransaction::TRANSACTIONTYPE:
+        case LegalpadDocumentTextTransaction::TRANSACTIONTYPE:
+          $is_contribution = true;
+          break;
+      }
+    }
+
+    if ($is_contribution) {
       $object->setVersions($object->getVersions() + 1);
       $body = $object->getDocumentBody();
       $body->setVersion($object->getVersions());
@@ -149,22 +64,6 @@ final class LegalpadDocumentEditor
     return $xactions;
   }
 
-  protected function mergeTransactions(
-    PhabricatorApplicationTransaction $u,
-    PhabricatorApplicationTransaction $v) {
-
-    $type = $u->getTransactionType();
-    switch ($type) {
-      case LegalpadTransaction::TYPE_TITLE:
-      case LegalpadTransaction::TYPE_TEXT:
-      case LegalpadTransaction::TYPE_SIGNATURE_TYPE:
-      case LegalpadTransaction::TYPE_PREAMBLE:
-      case LegalpadTransaction::TYPE_REQUIRE_SIGNATURE:
-        return $v;
-    }
-
-    return parent::mergeTransactions($u, $v);
-  }
 
 /* -(  Sending Mail  )------------------------------------------------------- */
 
@@ -201,10 +100,10 @@ final class LegalpadDocumentEditor
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
-      case LegalpadTransaction::TYPE_TEXT:
-      case LegalpadTransaction::TYPE_TITLE:
-      case LegalpadTransaction::TYPE_PREAMBLE:
-      case LegalpadTransaction::TYPE_REQUIRE_SIGNATURE:
+      case LegalpadDocumentTextTransaction::TRANSACTIONTYPE:
+      case LegalpadDocumentTitleTransaction::TRANSACTIONTYPE:
+      case LegalpadDocumentPreambleTransaction::TRANSACTIONTYPE:
+      case LegalpadDocumentRequireSignatureTransaction::TRANSACTIONTYPE:
         return true;
     }
 

src/applications/legalpad/storage/LegalpadTransaction.php

@@ -1,12 +1,6 @@
 <?php
 
-final class LegalpadTransaction extends PhabricatorApplicationTransaction {
-
-  const TYPE_TITLE = 'title';
-  const TYPE_TEXT = 'text';
-  const TYPE_SIGNATURE_TYPE = 'legalpad:signature-type';
-  const TYPE_PREAMBLE = 'legalpad:premable';
-  const TYPE_REQUIRE_SIGNATURE = 'legalpad:require-signature';
+final class LegalpadTransaction extends PhabricatorModularTransaction {
 
   public function getApplicationName() {
     return 'legalpad';
@@ -24,73 +18,8 @@ final class LegalpadTransaction extends PhabricatorApplicationTransaction {
     return new LegalpadTransactionView();
   }
 
-  public function shouldHide() {
-    $old = $this->getOldValue();
-
-    switch ($this->getTransactionType()) {
-      case self::TYPE_TITLE:
-      case self::TYPE_TEXT:
-        return ($old === null);
-      case self::TYPE_SIGNATURE_TYPE:
-        return true;
-    }
-
-    return parent::shouldHide();
-  }
-
-  public function getTitle() {
-    $author_phid = $this->getAuthorPHID();
-
-    $old = $this->getOldValue();
-    $new = $this->getNewValue();
-
-    $type = $this->getTransactionType();
-    switch ($type) {
-      case self::TYPE_TITLE:
-        return pht(
-          '%s renamed this document from "%s" to "%s".',
-          $this->renderHandleLink($author_phid),
-          $old,
-          $new);
-      case self::TYPE_TEXT:
-        return pht(
-          "%s updated the document's text.",
-          $this->renderHandleLink($author_phid));
-      case self::TYPE_PREAMBLE:
-        return pht(
-          '%s updated the preamble.',
-          $this->renderHandleLink($author_phid));
-      case self::TYPE_REQUIRE_SIGNATURE:
-        if ($new) {
-          $text = pht(
-            '%s set the document to require signatures.',
-            $this->renderHandleLink($author_phid));
-        } else {
-          $text = pht(
-            '%s set the document to not require signatures.',
-            $this->renderHandleLink($author_phid));
-        }
-        return $text;
-    }
-
-    return parent::getTitle();
-  }
-
-  public function hasChangeDetails() {
-    switch ($this->getTransactionType()) {
-      case self::TYPE_TITLE:
-      case self::TYPE_TEXT:
-      case self::TYPE_PREAMBLE:
-        return true;
-    }
-    return parent::hasChangeDetails();
-  }
-
-  public function renderChangeDetails(PhabricatorUser $viewer) {
-    return $this->renderTextCorpusChangeDetails(
-      $viewer,
-      $this->getOldValue(),
-      $this->getNewValue());
+  public function getBaseTransactionClass() {
+    return 'LegalpadDocumentTransactionType';
   }
 
 }

src/applications/legalpad/xaction/LegalpadDocumentPreambleTransaction.php

@@ -0,0 +1,57 @@
+<?php
+
+final class LegalpadDocumentPreambleTransaction
+  extends LegalpadDocumentTransactionType {
+
+  const TRANSACTIONTYPE = 'legalpad:premable';
+
+  public function generateOldValue($object) {
+    return $object->getPreamble();
+  }
+
+  public function applyInternalEffects($object, $value) {
+    $object->setPreamble($value);
+  }
+
+  public function getTitle() {
+    return pht(
+      '%s updated the document preamble.',
+      $this->renderAuthor());
+  }
+
+  public function getTitleForFeed() {
+    return pht(
+      '%s updated the document preamble for %s.',
+      $this->renderAuthor(),
+      $this->renderObject());
+  }
+
+  public function hasChangeDetailView() {
+    return true;
+  }
+
+  public function getMailDiffSectionHeader() {
+    return pht('CHANGES TO DOCUMENT PREAMBLE');
+  }
+
+  public function newChangeDetailView() {
+    $viewer = $this->getViewer();
+
+    return id(new PhabricatorApplicationTransactionTextDiffDetailView())
+      ->setViewer($viewer)
+      ->setOldText($this->getOldValue())
+      ->setNewText($this->getNewValue());
+  }
+
+  public function newRemarkupChanges() {
+    $changes = array();
+
+    $changes[] = $this->newRemarkupChange()
+      ->setOldValue($this->getOldValue())
+      ->setNewValue($this->getNewValue());
+
+    return $changes;
+  }
+
+
+}

src/applications/legalpad/xaction/LegalpadDocumentRequireSignatureTransaction.php

@@ -0,0 +1,58 @@
+<?php
+
+final class LegalpadDocumentRequireSignatureTransaction
+  extends LegalpadDocumentTransactionType {
+
+  const TRANSACTIONTYPE = 'legalpad:require-signature';
+
+  public function generateOldValue($object) {
+    return $object->getRequireSignature();
+  }
+
+  public function applyInternalEffects($object, $value) {
+    $object->setRequireSignature($value);
+  }
+
+  public function applyExternalEffects($object, $value) {
+    if (strlen($value)) {
+      $session = new PhabricatorAuthSession();
+      queryfx(
+        $session->establishConnection('w'),
+        'UPDATE %T SET signedLegalpadDocuments = 0',
+        $session->getTableName());
+    }
+  }
+
+  public function getTitle() {
+    $new = $this->getNewValue();
+    if ($new) {
+      return pht(
+        '%s set the document to require signatures.',
+        $this->renderAuthor());
+    } else {
+      return pht(
+        '%s set the document to not require signatures.',
+        $this->renderAuthor());
+    }
+  }
+
+  public function getTitleForFeed() {
+    $new = $this->getNewValue();
+    if ($new) {
+      return pht(
+        '%s set the document %s to require signatures.',
+        $this->renderAuthor(),
+        $this->renderObject());
+    } else {
+      return pht(
+        '%s set the document %s to not require signatures.',
+        $this->renderAuthor(),
+        $this->renderObject());
+    }
+  }
+
+  public function getIcon() {
+    return 'fa-pencil-square';
+  }
+
+}

src/applications/legalpad/xaction/LegalpadDocumentSignatureTypeTransaction.php

@@ -0,0 +1,29 @@
+<?php
+
+final class LegalpadDocumentSignatureTypeTransaction
+  extends LegalpadDocumentTransactionType {
+
+  const TRANSACTIONTYPE = 'legalpad:signature-type';
+
+  public function generateOldValue($object) {
+    return $object->getSignatureType();
+  }
+
+  public function applyInternalEffects($object, $value) {
+    $object->setSignatureType($value);
+  }
+
+  public function getTitle() {
+    return pht(
+      '%s set the document signature type.',
+      $this->renderAuthor());
+  }
+
+  public function getTitleForFeed() {
+    return pht(
+      '%s set the document signature type for %s.',
+      $this->renderAuthor(),
+      $this->renderObject());
+  }
+
+}

src/applications/legalpad/xaction/LegalpadDocumentTextTransaction.php

@@ -0,0 +1,60 @@
+<?php
+
+final class LegalpadDocumentTextTransaction
+  extends LegalpadDocumentTransactionType {
+
+  const TRANSACTIONTYPE = 'text';
+
+  public function generateOldValue($object) {
+    $body = $object->getDocumentBody();
+    return $body->getText();
+  }
+
+  public function applyInternalEffects($object, $value) {
+    $body = $object->getDocumentBody();
+    $body->setText($value);
+    $object->attachDocumentBody($body);
+  }
+
+  public function getTitle() {
+    return pht(
+      '%s updated the document text.',
+      $this->renderAuthor());
+  }
+
+  public function getTitleForFeed() {
+    return pht(
+      '%s updated the document text for %s.',
+      $this->renderAuthor(),
+      $this->renderObject());
+  }
+
+  public function hasChangeDetailView() {
+    return true;
+  }
+
+  public function getMailDiffSectionHeader() {
+    return pht('CHANGES TO DOCUMENT TEXT');
+  }
+
+  public function newChangeDetailView() {
+    $viewer = $this->getViewer();
+
+    return id(new PhabricatorApplicationTransactionTextDiffDetailView())
+      ->setViewer($viewer)
+      ->setOldText($this->getOldValue())
+      ->setNewText($this->getNewValue());
+  }
+
+  public function newRemarkupChanges() {
+    $changes = array();
+
+    $changes[] = $this->newRemarkupChange()
+      ->setOldValue($this->getOldValue())
+      ->setNewValue($this->getNewValue());
+
+    return $changes;
+  }
+
+
+}

src/applications/legalpad/xaction/LegalpadDocumentTitleTransaction.php

@@ -0,0 +1,58 @@
+<?php
+
+final class LegalpadDocumentTitleTransaction
+  extends LegalpadDocumentTransactionType {
+
+  const TRANSACTIONTYPE = 'title';
+
+  public function generateOldValue($object) {
+    return $object->getTitle();
+  }
+
+  public function applyInternalEffects($object, $value) {
+    $object->setTitle($value);
+    $body = $object->getDocumentBody();
+    $body->setTitle($value);
+    $object->attachDocumentBody($body);
+  }
+
+  public function getTitle() {
+    return pht(
+      '%s renamed this document from %s to %s.',
+      $this->renderAuthor(),
+      $this->renderOldValue(),
+      $this->renderNewValue());
+  }
+
+  public function getTitleForFeed() {
+    return pht(
+      '%s renamed document %s from %s to %s.',
+      $this->renderAuthor(),
+      $this->renderObject(),
+      $this->renderOldValue(),
+      $this->renderNewValue());
+  }
+
+  public function validateTransactions($object, array $xactions) {
+    $errors = array();
+
+    if ($this->isEmptyTextTransaction($object->getTitle(), $xactions)) {
+      $errors[] = $this->newRequiredError(
+        pht('Documents must have a title.'));
+    }
+
+    $max_length = $object->getColumnMaximumByteLength('title');
+    foreach ($xactions as $xaction) {
+      $new_value = $xaction->getNewValue();
+      $new_length = strlen($new_value);
+      if ($new_length > $max_length) {
+        $errors[] = $this->newInvalidError(
+          pht('The title can be no longer than %s characters.',
+          new PhutilNumber($max_length)));
+      }
+    }
+
+    return $errors;
+  }
+
+}

src/applications/legalpad/xaction/LegalpadDocumentTransactionType.php

@@ -0,0 +1,4 @@
+<?php
+
+abstract class LegalpadDocumentTransactionType
+  extends PhabricatorModularTransactionType {}