Add Pdo\Sqlite::backup()

UPGRADING

@@ -132,6 +132,9 @@ PHP 8.6 UPGRADE NOTES
 6. New Functions
 ========================================
 
+- Pdo_Sqlite:
+  . Pdo\Sqlite::backup() analogous to Sqlite3::backup().
+
 - Reflection:
   . ReflectionConstant::inNamespace()
   . Added ReflectionProperty::isReadable() and ReflectionProperty::isWritable().

ext/pdo_sqlite/pdo_sqlite.c

@@ -362,6 +362,57 @@ PHP_METHOD(Pdo_Sqlite, setAuthorizer)
 	RETURN_THROWS();
 }
 
+PHP_METHOD(Pdo_Sqlite, backup)
+{
+	zval *destination_object;
+	char *source_dbname = "main", *destination_dbname = "main";
+	size_t source_dbname_len, destination_dbname_len;
+	int rc;
+
+	ZEND_PARSE_PARAMETERS_START(1, 3)
+		Z_PARAM_OBJECT_OF_CLASS(destination_object, pdosqlite_ce)
+		Z_PARAM_OPTIONAL
+		Z_PARAM_PATH(source_dbname, source_dbname_len)
+		Z_PARAM_PATH(destination_dbname, destination_dbname_len)
+	ZEND_PARSE_PARAMETERS_END();
+
+	pdo_dbh_t *dbh = Z_PDO_DBH_P(destination_object);
+	PDO_CONSTRUCT_CHECK;
+	pdo_sqlite_db_handle *destination_db_handle = dbh->driver_data;
+	dbh = Z_PDO_DBH_P(ZEND_THIS);
+	PDO_CONSTRUCT_CHECK;
+	pdo_sqlite_db_handle *source_db_handle = dbh->driver_data;
+
+	sqlite3_backup *dbBackup = sqlite3_backup_init(destination_db_handle->db, destination_dbname, source_db_handle->db, source_dbname);
+
+	if (dbBackup) {
+		do {
+			rc = sqlite3_backup_step(dbBackup, -1);
+		} while (rc == SQLITE_OK);
+
+		/* Release resources allocated by sqlite3_backup_init(). */
+		rc = sqlite3_backup_finish(dbBackup);
+	} else {
+		rc = sqlite3_errcode(source_db_handle->db);
+	}
+
+	if (rc != SQLITE_OK) {
+		if (rc == SQLITE_BUSY) {
+			pdo_raise_impl_error(dbh, NULL, "HY000", "Backup failed: source database is busy");
+		} else if (rc == SQLITE_LOCKED) {
+			pdo_raise_impl_error(dbh, NULL, "HY000", "Backup failed: source database is locked");
+		} else {
+			char *message;
+			spprintf(&message, 0, "Backup failed: %s", sqlite3_errmsg(source_db_handle->db));
+			pdo_raise_impl_error(dbh, NULL, "HY000", message);
+			efree(message);
+		}
+		RETURN_FALSE;
+	}
+
+	RETURN_TRUE;
+}
+
 static int php_sqlite_collation_callback(void *context, int string1_len, const void *string1,
 	int string2_len, const void *string2)
 {

ext/pdo_sqlite/pdo_sqlite.stub.php

@@ -94,4 +94,6 @@ public function openBlob(
     ) {}
 
     public function setAuthorizer(?callable $callback): void {}
+
+    public function backup(Sqlite $destination, string $sourceDatabase = "main", string $destinationDatabase = "main"): bool {}
 }

ext/pdo_sqlite/tests/subclasses/pdo_sqlite_backup.phpt

@@ -0,0 +1,83 @@
+--TEST--
+Pdo\Sqlite::backup test
+--EXTENSIONS--
+pdo
+pdo_sqlite
+--FILE--
+<?php
+
+$db = Pdo::connect('sqlite::memory:');
+
+$db->exec('CREATE TABLE test (a, b);');
+$db->exec('INSERT INTO test VALUES (42, \'php\');');
+
+$db2 = Pdo::connect('sqlite::memory:');
+
+echo "Backup to DB2\n";
+var_dump($db->backup($db2));
+
+echo "Checking if table has been copied\n";
+var_dump($db2->query('SELECT COUNT(*) FROM sqlite_master;')->fetchAll());
+
+echo "Checking backup contents\n";
+var_dump($db2->query('SELECT a FROM test;')->fetchAll());
+var_dump($db2->query('SELECT b FROM test;')->fetchAll());
+
+echo "Resetting DB2\n";
+
+unset($db2);
+$db2 = Pdo::connect('sqlite::memory:');
+
+echo "Locking DB1\n";
+var_dump($db->exec('BEGIN EXCLUSIVE;'));
+
+echo "Backup to DB2 (should fail)\n";
+try {
+    $db->backup($db2);
+} catch (PDOException $e) {
+    echo $e->getMessage(), "\n";
+}
+$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_WARNING);
+var_dump($db->backup($db2));
+
+?>
+--EXPECTF--
+Backup to DB2
+bool(true)
+Checking if table has been copied
+array(1) {
+  [0]=>
+  array(2) {
+    ["COUNT(*)"]=>
+    int(1)
+    [0]=>
+    int(1)
+  }
+}
+Checking backup contents
+array(1) {
+  [0]=>
+  array(2) {
+    ["a"]=>
+    int(42)
+    [0]=>
+    int(42)
+  }
+}
+array(1) {
+  [0]=>
+  array(2) {
+    ["b"]=>
+    string(3) "php"
+    [0]=>
+    string(3) "php"
+  }
+}
+Resetting DB2
+Locking DB1
+int(1)
+Backup to DB2 (should fail)
+SQLSTATE[HY000]: General error: Backup failed: source database is busy
+
+Warning: Pdo\Sqlite::backup(): SQLSTATE[HY000]: General error: Backup failed: source database is busy in %s on line %d
+bool(false)