fix hanging of write on Windows

When using File::Write(), Var size in int64_t is casted to DWORD(unsigned long). When Var size is out of DWORD range, casted value will be zero. Before calling into File::Write() on Windows, validate the size.

Bug: https://github.com/dart-lang/sdk/issues/40339
Change-Id: I36fade62dfa3025f418405cb3e45c286dd6b7db1
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/134440
Reviewed-by: Zach Anderson <zra@google.com>
Commit-Queue: Zichang Guo <zichangguo@google.com>

runtime/bin/file_win.cc

@@ -146,10 +146,15 @@ int64_t File::Read(void* buffer, int64_t num_bytes) {
 
 int64_t File::Write(const void* buffer, int64_t num_bytes) {
   int fd = handle_->fd();
-  ASSERT(fd >= 0);
+  // TODO(zichangguo): num_bytes from signed integer to unsigned integer.
+  ASSERT(fd >= 0 && num_bytes >= 0);
   HANDLE handle = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
+  // On Windows, int64_t is much larger than required size DWORD(unsigned long).
+  // Limit the size to be a valid DWORD(unsigned long).
+  COMPILE_ASSERT(sizeof(uint32_t) == sizeof(DWORD));
+  DWORD bytes_to_write = num_bytes > MAXDWORD ? MAXDWORD : num_bytes;
   DWORD written = 0;
-  BOOL result = WriteFile(handle, buffer, num_bytes, &written, NULL);
+  BOOL result = WriteFile(handle, buffer, bytes_to_write, &written, NULL);
   if (!result) {
     return -1;
   }

tests/standalone_2/io/file_write_as_test.dart

@@ -4,6 +4,7 @@
 
 import 'dart:async';
 import 'dart:io';
+import 'dart:typed_data';
 
 import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
@@ -27,6 +28,19 @@ testWriteAsStringSync(dir) {
   Expect.equals('$data$data', f.readAsStringSync());
 }
 
+testWriteWithLargeList(dir) {
+  var f;
+  if (Platform.isWindows) {
+    f = File('NUL');
+  } else {
+    f = File('/dev/null');
+  }
+  // 0x100000000 exceeds the maximum of unsigned long.
+  // This should no longer hang.
+  // Issue: https://github.com/dart-lang/sdk/issues/40339
+  f.writeAsBytesSync(Uint8List(0x100000000));
+}
+
 Future testWriteAsBytes(dir) {
   var completer = new Completer();
   var f = new File('${dir.path}/bytes.txt');
@@ -73,6 +87,7 @@ main() {
   var tempDir = Directory.systemTemp.createTempSync('dart_file_write_as');
   testWriteAsBytesSync(tempDir);
   testWriteAsStringSync(tempDir);
+  testWriteWithLargeList(tempDir);
   testWriteAsBytes(tempDir).then((_) {
     return testWriteAsString(tempDir);
   }).then((_) {