Rewrite file-system-watcher to better handle the different system APIs.

runtime/bin/file_system_watcher_win.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_WINDOWS)
 
 #include "bin/file_system_watcher.h"
 #include "bin/eventhandler.h"
 
 #include <WinIoCtl.h>  // NOLINT
 
 #include "bin/builtin.h"
 #include "bin/log.h"
 #include "bin/utils.h"
 
 
 namespace dart {
 namespace bin {
 
 bool FileSystemWatcher::IsSupported() {
   return true;
 }
 
 
-intptr_t FileSystemWatcher::WatchPath(const char* path,
+intptr_t FileSystemWatcher::Init() {
+  return 0;
+}
+
+
+void FileSystemWatcher::Close(intptr_t id) {
+  USE(id);
+}
+
+
+intptr_t FileSystemWatcher::WatchPath(intptr_t id,
+                                      const char* path,
                                       int events,
                                       bool recursive) {
+  USE(id);
   const wchar_t* name = StringUtils::Utf8ToWide(path);
   HANDLE dir = CreateFileW(name,
                            FILE_LIST_DIRECTORY,
                            FILE_SHARE_READ |
                                FILE_SHARE_WRITE |
                                FILE_SHARE_DELETE,
                            NULL,
                            OPEN_EXISTING,
                            FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,
                            NULL);
@@ skipping 13 matching lines @@
   DirectoryWatchHandle* handle =
       new DirectoryWatchHandle(dir, list_events, recursive);
   // Issue a read directly, to be sure events are tracked from now on. This is
   // okay, since in Dart, we create the socket and start reading immidiately.
   handle->EnsureInitialized(EventHandler::delegate());
   handle->IssueRead();
   return reinterpret_cast<intptr_t>(handle);
 }
 
 
-void FileSystemWatcher::UnwatchPath(intptr_t id) {
-  // Nothing to do.
+void FileSystemWatcher::UnwatchPath(intptr_t id, intptr_t path_id) {
+  USE(id);
+  USE(path_id);
 }
 
 
-intptr_t FileSystemWatcher::GetSocketId(intptr_t id) {
-  return id;
+intptr_t FileSystemWatcher::GetSocketId(intptr_t id, intptr_t path_id) {
+  USE(id);
+  return path_id;
 }
 
 
-Dart_Handle FileSystemWatcher::ReadEvents(intptr_t id) {
+Dart_Handle FileSystemWatcher::ReadEvents(intptr_t id, intptr_t path_id) {
+  USE(id);
   const intptr_t kEventSize = sizeof(FILE_NOTIFY_INFORMATION);
-  DirectoryWatchHandle* dir = reinterpret_cast<DirectoryWatchHandle*>(id);
+  DirectoryWatchHandle* dir = reinterpret_cast<DirectoryWatchHandle*>(path_id);
   intptr_t available = dir->Available();
   intptr_t max_count = available / kEventSize + 1;
   Dart_Handle events = Dart_NewList(max_count);
   uint8_t* buffer = new uint8_t[available];
   intptr_t bytes = dir->Read(buffer, available);
   intptr_t offset = 0;
   intptr_t i = 0;
   while (offset < bytes) {
     FILE_NOTIFY_INFORMATION* e =
         reinterpret_cast<FILE_NOTIFY_INFORMATION*>(buffer + offset);
 
-    Dart_Handle event = Dart_NewList(4);
+    Dart_Handle event = Dart_NewList(5);
     int mask = 0;
     if (e->Action == FILE_ACTION_ADDED) mask |= kCreate;
     if (e->Action == FILE_ACTION_REMOVED) mask |= kDelete;
     if (e->Action == FILE_ACTION_MODIFIED) mask |= kModifyContent;
     if (e->Action == FILE_ACTION_RENAMED_OLD_NAME) mask |= kMove;
     if (e->Action == FILE_ACTION_RENAMED_NEW_NAME) mask |= kMove;
     Dart_ListSetAt(event, 0, Dart_NewInteger(mask));
     // Move events come in pairs. Just 'enable' by default.
     Dart_ListSetAt(event, 1, Dart_NewInteger(1));
     Dart_ListSetAt(event, 2, Dart_NewStringFromUTF16(
         reinterpret_cast<uint16_t*>(e->FileName), e->FileNameLength / 2));
     Dart_ListSetAt(event, 3, Dart_NewBoolean(true));
+    Dart_ListSetAt(event, 4, Dart_NewInteger(path_id));
     Dart_ListSetAt(events, i, event);
     i++;
     if (e->NextEntryOffset == 0) break;
     offset += e->NextEntryOffset;
   }
   delete[] buffer;
   return events;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)