[FEATURE] Allow to restrict number of items by CType

Classes/Form/FormDataProvider/TcaColPosItems.php

@@ -94,6 +94,21 @@ public function addData(array $result)
                 }
             }
 
+            $cType = $record['CType'][0];
+            if (!empty($columnConfiguration['maxitemsByCType.'][$cType])
+                && $columnConfiguration['maxitemsByCType.'][$cType] <= $this->contentRepository->countColPosByRecordType($record, $cType)
+            ) {
+                $isCurrentColPos = $colPos === (int)$result['databaseRow']['colPos'][0];
+                if ($isCurrentColPos && !$this->contentRepository->isRecordInColPos($record)) {
+                    throw new AccessDeniedColPosException(
+                        'Maximum number of allowed content elements by CType "' . $cType . '" (' . $columnConfiguration['maxitemsByCType.'][$cType] . ') reached.',
+                        1749209557
+                    );
+                } elseif (!$isCurrentColPos) {
+                    unset($result['processedTca']['columns']['colPos']['config']['items'][$key]);
+                }
+            }
+
             if (!empty($columnConfiguration['maxitems'])
                 && $columnConfiguration['maxitems'] <= $this->contentRepository->countColPosByRecord($record)
             ) {

Classes/Hooks/AbstractDataHandlerHook.php

@@ -138,4 +138,22 @@ protected function isRecordAllowedByItemsCount(array $columnConfiguration, array
 
         return (int)$columnConfiguration['maxitems'] >= $this->contentRepository->addRecordToColPos($record);
     }
+
+    /**
+     * @param array $columnConfiguration
+     * @param array $record
+     * @return bool
+     */
+    protected function isRecordAllowedByItemsCountAndCType(array $columnConfiguration, array $record)
+    {
+        $cType = $record['CType'];
+        if (!empty($columnConfiguration['maxitemsByCType.'])) {
+            $this->contentRepository->addRecordToColPos($record);
+            if ($this->contentRepository->countColPosByRecordType($record, $cType) >= (int)$columnConfiguration['maxitemsByCType.']) {
+                return false;
+            }
+        }
+
+        return true;
+    }
 }

Classes/Hooks/DatamapDataHandlerHook.php

@@ -70,6 +70,30 @@ public function processDatamap_beforeStart(DataHandler $dataHandler)
                 );
             }
 
+            if (!$this->isRecordAllowedByItemsCountAndCType($columnConfiguration, $incomingFieldArray)) {
+                // DataHandler copies a record by first add a new content element (in the old colPos) and then adjust
+                // the colPos information to the target colPos. This means we have to allow this element to be added
+                // even if the maxitems is reached already. The copy command was checked in CmdmapDataHandlerHook.
+                if (empty($dataHandler->cmdmap) && !empty($_POST['CB']['paste'] ?? $_GET['CB']['paste'] ?? null)) {
+                    continue;
+                }
+                $cType = $incomingFieldArray['CType'];
+                unset($dataHandler->datamap['tt_content'][$id]);
+                $dataHandler->log(
+                    'tt_content',
+                    $id,
+                    1,
+                    $pageId,
+                    1,
+                    'The record "%s" couldn\'t be saved due to reached maxitemsByCType configuration of %d.',
+                    27,
+                    [
+                        $incomingFieldArray[$GLOBALS['TCA']['tt_content']['ctrl']['label']],
+                        $columnConfiguration['maxitemsByCType.'][$cType],
+                    ]
+                );
+            }
+
             if (!$this->isRecordAllowedByItemsCount($columnConfiguration, $incomingFieldArray)) {
                 // DataHandler copies a record by first add a new content element (in the old colPos) and then adjust
                 // the colPos information to the target colPos. This means we have to allow this element to be added

Classes/Repository/ContentRepository.php

@@ -46,6 +46,21 @@ public function countColPosByRecord(array $record): int
         return count($this->colPosCount[$identifier]);
     }
 
+    public function countColPosByRecordType(array $record, string $cType): int
+    {
+        $identifier = $this->getIdentifier($record);
+
+        if (!isset($this->colPosCount[$identifier])) {
+            $this->initialize($record);
+        }
+
+        $colPosCountState = $this->colPosCount[$identifier];
+        $allEntries = $colPosCountState[null];
+        $countByCType = array_count_values($allEntries);
+
+        return $countByCType[$cType] ?? 0;
+    }
+
     public function addRecordToColPos(array $record): int
     {
         $identifier = $this->getIdentifier($record);
@@ -118,7 +133,7 @@ protected function fetchRecordsForColPos(array $record): array
         $languageField = $GLOBALS['TCA']['tt_content']['ctrl']['languageField'];
         $language = (array)($record[$languageField] ?? 0);
 
-        $selectFields = ['uid', 'pid'];
+        $selectFields = ['uid', 'pid', 'CType'];
         if (!empty($GLOBALS['TCA']['tt_content']['ctrl']['versioningWS'])) {
             $selectFields[] = 't3ver_state';
         }
@@ -151,7 +166,8 @@ protected function fetchRecordsForColPos(array $record): array
             BackendUtility::workspaceOL('tt_content', $row, -99, true);
             if (is_array($row) && !VersionState::cast($row['t3ver_state'])->equals(VersionState::DELETE_PLACEHOLDER)) {
                 $uid = ($row['_ORIG_uid'] ?? 0) ?: $row['uid'];
-                $rows[$uid] = $uid;
+                $cType = $row['CType'];
+                $rows[$uid] = $cType;
             }
         }
 

README.md

@@ -128,6 +128,25 @@ columns {
 }
 ```
 
+- To restrict the number of content elements by type use `maxitemsByCType.[type] = [number of elements]`
+
+*Example:*
+```
+columns {
+    1 {
+        name = Column with one textmedia 
+        colPos = 3
+        colspan = 6
+        allowed {
+            CType = textmedia, header
+        }
+        maxitemsByCType {
+            header = 1
+        }
+    }
+}
+```
+
 ## Known issues
 
 ### TypeError