DownloadManagerDelegate::ShouldCompleteDownload(callback)

chrome/browser/download/download_completion_blocker.h

+// 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.
+
+#ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_COMPLETION_BLOCKER_H_
+#define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_COMPLETION_BLOCKER_H_
+#pragma once
+
+#include "base/callback.h"
+#include "content/public/browser/download_item.h"
+
+// A subsystem may use a DownloadCompletionBlocker in conjunction with
+// DownloadManagerDelegate::ShouldCompleteDownload() in order to block the
+// completion of a DownloadItem. CompleteDownload() will run the most recent
+// callback set.
+class DownloadCompletionBlocker : public content::DownloadItem::ExternalData {
+ public:
+  DownloadCompletionBlocker();
+  virtual ~DownloadCompletionBlocker();
+
+  bool is_complete() const { return is_complete_; }
+
+  void set_callback(const base::Closure& callback) {
+    if (!is_complete())
+      callback_ = callback;
+  }
+
+  // Mark this download item as complete with respect to this blocker. (Other
+  // blockers may continue to block the item.) Run |callback_|. This method may
+  // only be called once, so |callback_| will only be called once.  Subclasses
+  // must call the base implementation if they override this method.
+  virtual void CompleteDownload();
+
+ private:
+  bool is_complete_;
+  base::Closure callback_;
+
+  DISALLOW_COPY_AND_ASSIGN(DownloadCompletionBlocker);
+};
+
+#endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_COMPLETION_BLOCKER_H_