Refactor FileIO to the new design

ppapi/shared_impl/file_io_state_manager.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ppapi/shared_impl/file_io_state_manager.h"
+
+#include "base/logging.h"
+#include "ppapi/c/pp_errors.h"
+
+namespace ppapi {
+
+FileIOStateManager::FileIOStateManager()
+    : num_pending_ops_(0),
+      pending_op_(OPERATION_NONE),
+      file_open_(false) {
+}
+
+FileIOStateManager::~FileIOStateManager() {
+}
+
+void FileIOStateManager::SetOpenSucceed() {
+  file_open_ = true;
+}
+
+int32_t FileIOStateManager::CheckOperationState(OperationType new_op,
+                                                bool should_be_open) {
+  if (should_be_open) {
+    if (!file_open_)
+      return PP_ERROR_FAILED;
+  } else {
+    if (file_open_)
+      return PP_ERROR_FAILED;
+  }
+
+  if (pending_op_ != OPERATION_NONE &&
+      (pending_op_ != new_op || pending_op_ == OPERATION_EXCLUSIVE))
+    return PP_ERROR_INPROGRESS;
+
+  return PP_OK;
+}
+
+void FileIOStateManager::SetPendingOperation(OperationType new_op) {
+  DCHECK(pending_op_ == OPERATION_NONE ||
+         (pending_op_ != OPERATION_EXCLUSIVE && pending_op_ == new_op));
+  pending_op_ = new_op;
+  num_pending_ops_++;
+}
+
+void FileIOStateManager::SetOperationFinished() {
+  DCHECK(num_pending_ops_ > 0);
+  if (--num_pending_ops_ == 0)
+    pending_op_ = OPERATION_NONE;
+}
+
+}  // namespace ppapi