Fixup access flags for checking files (without actually creating them)

Author: carlopi

packages/duckdb-wasm/src/bindings/runtime.ts

@@ -58,6 +58,11 @@ export enum FileFlags {
     FILE_FLAGS_FILE_CREATE_NEW = 1 << 4,
     //! Open file in append mode
     FILE_FLAGS_APPEND = 1 << 5,
+    FILE_FLAGS_PRIVATE = 1 << 6,
+    FILE_FLAGS_NULL_IF_NOT_EXISTS = 1 << 7,
+    FILE_FLAGS_PARALLEL_ACCESS = 1 << 8,
+    FILE_FLAGS_EXCLUSIVE_CREATE = 1 << 9,
+    FILE_FLAGS_NULL_IF_EXISTS = 1 << 10
 }
 
 /** Configuration for the AWS S3 Filesystem */

packages/duckdb-wasm/src/bindings/runtime_browser.ts

@@ -381,6 +381,11 @@ export const BROWSER_RUNTIME: DuckDBRuntime & {
                         return result;
                     }
 
+                    // Depending on file flags, return nullptr
+                    if (flags & FileFlags.FILE_FLAGS_NULL_IF_NOT_EXISTS) {
+                       return 0;
+                    }
+
                     // Fall back to empty buffered file in the browser
                     console.warn(`Buffering missing file: ${file.fileName}`);
                     const result = mod._malloc(2 * 8);

packages/duckdb-wasm/src/bindings/runtime_node.ts

@@ -76,6 +76,11 @@ export const NODE_RUNTIME: DuckDBRuntime & {
                 case DuckDBDataProtocol.NODE_FS: {
                     let fd = NODE_RUNTIME._files?.get(file.dataUrl!);
                     if (fd === null || fd === undefined) {
+                        // Depending on file flags, return nullptr
+                        if (flags & FileFlags.FILE_FLAGS_NULL_IF_NOT_EXISTS) {
+                            return 0;
+                        }
+
                         fd = fs.openSync(
                             file.dataUrl!,
                             fs.constants.O_CREAT | fs.constants.O_RDWR,

patches/duckdb/fix_load_database.patch

@@ -1,20 +1,23 @@
 diff --git a/src/storage/storage_manager.cpp b/src/storage/storage_manager.cpp
-index cb6c654e5f..a6b2af3b85 100644
+index 45d42174f1..10b3ce47b1 100644
 --- a/src/storage/storage_manager.cpp
 +++ b/src/storage/storage_manager.cpp
-@@ -160,9 +160,12 @@ void SingleFileStorageManager::LoadDatabase(StorageOptions storage_options) {
+@@ -162,9 +162,15 @@ void SingleFileStorageManager::LoadDatabase(StorageOptions storage_options) {
  			    row_group_size, STANDARD_VECTOR_SIZE);
  		}
  	}
 -	// Check if the database file already exists.
 -	// Note: a file can also exist if there was a ROLLBACK on a previous transaction creating that file.
 -	if (!read_only && !fs.FileExists(path)) {
-+    auto db_file_handle = fs.OpenFile(path, FileFlags::FILE_FLAGS_READ | FileFlags::FILE_FLAGS_NULL_IF_NOT_EXISTS);
-+    bool is_empty_file = db_file_handle->GetFileSize() == 0;
-+    db_file_handle.reset();
++	bool is_empty_file = true;
++	auto db_file_handle = fs.OpenFile(path, FileFlags::FILE_FLAGS_READ | FileFlags::FILE_FLAGS_NULL_IF_NOT_EXISTS);
++	if (db_file_handle && db_file_handle->GetFileSize() != 0) {
++		is_empty_file = false;
++		db_file_handle.reset();
++	}
 +
-+ 	// first check if the database exists
-+	if (!read_only && ( !fs.FileExists(path) || ( options.use_direct_io && is_empty_file )) ) {
++	// first check if the database exists
++	if (!read_only && (!fs.FileExists(path) || (options.use_direct_io && is_empty_file))) {
  		// file does not exist and we are in read-write mode
  		// create a new file