API rescue master-branch PR: Use Generators for ORM

src/Forms/GridField/GridFieldExportButton.php

@@ -223,10 +223,6 @@ public function generateExportFileData($gridField)
 
         // Remove limit as the list may be paginated, we want the full list for the export
         $items = $items->limit(null);
-        // Use Generator in applicable cases to reduce memory consumption
-        $items = $items instanceof DataList
-            ? $items->getGenerator()
-            : $items;
 
         /** @var DataObject $item */
         foreach ($items as $item) {

src/ORM/ArrayList.php

@@ -2,8 +2,8 @@
 
 namespace SilverStripe\ORM;
 
-use ArrayIterator;
 use InvalidArgumentException;
+use Iterator;
 use LogicException;
 use SilverStripe\Dev\Debug;
 use SilverStripe\Dev\Deprecation;
@@ -103,19 +103,16 @@ public function exists()
     /**
      * Returns an Iterator for this ArrayList.
      * This function allows you to use ArrayList in foreach loops
-     *
-     * @return ArrayIterator
      */
-    #[\ReturnTypeWillChange]
-    public function getIterator()
-    {
-        $items = array_map(
-            function ($item) {
-                return is_array($item) ? new ArrayData($item) : $item;
-            },
-            $this->items ?? []
-        );
-        return new ArrayIterator($items);
+    public function getIterator(): Iterator
+    {
+        foreach ($this->items as $i => $item) {
+            if (is_array($item)) {
+                yield new ArrayData($item);
+            } else {
+                yield $item;
+            }
+        }
     }
 
     /**

src/ORM/Connect/DBSchemaManager.php

@@ -380,7 +380,7 @@ public function requireTable(
             if ($dbID && isset($options[$dbID])) {
                 if (preg_match('/ENGINE=([^\s]*)/', $options[$dbID] ?? '', $alteredEngineMatches)) {
                     $alteredEngine = $alteredEngineMatches[1];
-                    $tableStatus = $this->query(sprintf('SHOW TABLE STATUS LIKE \'%s\'', $table))->first();
+                    $tableStatus = $this->query(sprintf('SHOW TABLE STATUS LIKE \'%s\'', $table))->record();
                     $tableOptionsChanged = ($tableStatus['Engine'] != $alteredEngine);
                 }
             }

src/ORM/Connect/MySQLQuery.php

@@ -2,6 +2,8 @@
 
 namespace SilverStripe\ORM\Connect;
 
+use Iterator;
+
 /**
  * A result-set from a MySQL database (using MySQLiConnector)
  * Note that this class is only used for the results of non-prepared statements
@@ -45,44 +47,21 @@ public function __destruct()
         }
     }
 
-    public function seek($row)
+    public function getIterator(): Iterator
     {
         if (is_object($this->handle)) {
-            // Fix for https://github.com/silverstripe/silverstripe-framework/issues/9097 without breaking the seek() API
-            $this->handle->data_seek($row);
-            $result = $this->nextRecord();
-            $this->handle->data_seek($row);
-            return $result;
+            while ($data = $this->handle->fetch_assoc()) {
+                yield $data;
+            }
         }
-        return null;
     }
 
     public function numRecords()
     {
         if (is_object($this->handle)) {
             return $this->handle->num_rows;
         }
-        return null;
-    }
 
-    public function nextRecord()
-    {
-        $floatTypes = [MYSQLI_TYPE_FLOAT, MYSQLI_TYPE_DOUBLE, MYSQLI_TYPE_DECIMAL, MYSQLI_TYPE_NEWDECIMAL];
-
-        if (is_object($this->handle) && ($row = $this->handle->fetch_array(MYSQLI_NUM))) {
-            $data = [];
-            foreach ($row as $i => $value) {
-                if (!isset($this->columns[$i])) {
-                    throw new DatabaseException("Can't get metadata for column $i");
-                }
-                if (in_array($this->columns[$i]->type, $floatTypes ?? [])) {
-                    $value = (float)$value;
-                }
-                $data[$this->columns[$i]->name] = $value;
-            }
-            return $data;
-        } else {
-            return false;
-        }
+        return null;
     }
 }

src/ORM/Connect/MySQLStatement.php

@@ -2,6 +2,7 @@
 
 namespace SilverStripe\ORM\Connect;
 
+use Iterator;
 use mysqli_result;
 use mysqli_stmt;
 
@@ -56,6 +57,26 @@ class MySQLStatement extends Query
      */
     protected $boundValues = [];
 
+    /**
+     * Hook the result-set given into a Query class, suitable for use by SilverStripe.
+     * @param mysqli_stmt $statement The related statement, if present
+     * @param mysqli_result $metadata The metadata for this statement
+     */
+    public function __construct($statement, $metadata)
+    {
+        $this->statement = $statement;
+        $this->metadata = $metadata;
+
+        // Immediately bind and buffer
+        $this->bind();
+    }
+
+    public function __destruct()
+    {
+        $this->statement->close();
+        $this->currentRecord = false;
+    }
+
     /**
      * Binds this statement to the variables
      */
@@ -82,58 +103,20 @@ protected function bind()
         call_user_func_array([$this->statement, 'bind_result'], $variables ?? []);
     }
 
-    /**
-     * Hook the result-set given into a Query class, suitable for use by SilverStripe.
-     * @param mysqli_stmt $statement The related statement, if present
-     * @param mysqli_result $metadata The metadata for this statement
-     */
-    public function __construct($statement, $metadata)
-    {
-        $this->statement = $statement;
-        $this->metadata = $metadata;
-
-        // Immediately bind and buffer
-        $this->bind();
-    }
-
-    public function __destruct()
+    public function getIterator(): Iterator
     {
-        $this->statement->close();
-        $this->currentRecord = false;
-    }
-
-    public function seek($row)
-    {
-        $this->rowNum = $row - 1;
-
-        // Fix for https://github.com/silverstripe/silverstripe-framework/issues/9097 without breaking the seek() API
-        $this->statement->data_seek($row);
-        $result = $this->next();
-        $this->statement->data_seek($row);
-        return $result;
+        while ($this->statement->fetch()) {
+            // Dereferenced row
+            $row = [];
+            foreach ($this->boundValues as $key => $value) {
+                $row[$key] = $value;
+            }
+            yield $row;
+        }
     }
 
     public function numRecords()
     {
         return $this->statement->num_rows();
     }
-
-    public function nextRecord()
-    {
-        // Skip data if out of data
-        if (!$this->statement->fetch()) {
-            return false;
-        }
-
-        // Dereferenced row
-        $row = [];
-        foreach ($this->boundValues as $key => $value) {
-            $floatTypes = [MYSQLI_TYPE_FLOAT, MYSQLI_TYPE_DOUBLE, MYSQLI_TYPE_DECIMAL, MYSQLI_TYPE_NEWDECIMAL];
-            if (in_array($this->types[$key], $floatTypes ?? [])) {
-                $value = (float)$value;
-            }
-            $row[$key] = $value;
-        }
-        return $row;
-    }
 }

src/ORM/Connect/PDOQuery.php

@@ -2,6 +2,9 @@
 
 namespace SilverStripe\ORM\Connect;
 
+use ArrayIterator;
+use Iterator;
+
 /**
  * A result-set from a PDO database.
  */
@@ -14,7 +17,7 @@ class PDOQuery extends Query
 
     /**
      * Hook the result-set given into a Query class, suitable for use by SilverStripe.
-     * @param PDOStatement $statement The internal PDOStatement containing the results
+     * @param PDOStatementHandle $statement The internal PDOStatement containing the results
      */
     public function __construct(PDOStatementHandle $statement)
     {
@@ -26,25 +29,13 @@ public function __construct(PDOStatementHandle $statement)
         $statement->closeCursor();
     }
 
-    public function seek($row)
+    public function getIterator(): Iterator
     {
-        $this->rowNum = $row - 1;
-        return $this->nextRecord();
+        return new ArrayIterator($this->results);
     }
 
     public function numRecords()
     {
-        return count($this->results ?? []);
-    }
-
-    public function nextRecord()
-    {
-        $index = $this->rowNum + 1;
-
-        if (isset($this->results[$index])) {
-            return $this->results[$index];
-        } else {
-            return false;
-        }
+        return count($this->results);
     }
 }