Support dragging a virtual file out of the browser.

app/os_exchange_data.h

 // Copyright (c) 2009 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 APP_OS_EXCHANGE_DATA_H_
 #define APP_OS_EXCHANGE_DATA_H_
 
 #include "build/build_config.h"
 
 #include <set>
 #include <string>
 #include <vector>
 
 #if defined(OS_WIN)
 #include <objidl.h>
 #elif defined(OS_LINUX)
 #include <gtk/gtk.h>
 #endif
 
 #include "base/basictypes.h"
+#include "base/file_path.h"
+#include "base/ref_counted.h"
 #include "base/scoped_ptr.h"
 
 class GURL;
 class Pickle;
 
 ///////////////////////////////////////////////////////////////////////////////
 //
 // OSExchangeData
 //  An object that holds interchange data to be sent out to OS services like
 //  clipboard, drag and drop, etc. This object exposes an API that clients can
@@ skipping 21 matching lines @@
     STRING         = 1 << 0,
     URL            = 1 << 1,
     FILE_NAME      = 1 << 2,
     PICKLED_DATA   = 1 << 3,
 #if defined(OS_WIN)
     FILE_CONTENTS  = 1 << 4,
     HTML           = 1 << 5,
 #endif
   };
 
+  struct DownloadFileInfo;
+
+  // Defines the interface to observe the status of file download.
+  class DownloadFileObserver : public base::RefCounted<DownloadFileObserver> {
+   public:
+    // The caller is responsible to free the DownloadFileInfo objects passed
+    // in the vector parameter.
+    virtual void OnDataReady(
+        int format,
+        const std::vector<DownloadFileInfo*>& downloads) = 0;
+
+   protected:
+    friend class base::RefCounted<DownloadFileObserver>;
+    virtual ~DownloadFileObserver() {}
+  };
+
+  // Defines the interface to control how a file is downloaded.
+  class DownloadFileProvider :
+      public base::RefCountedThreadSafe<DownloadFileProvider> {
+   public:
+    virtual bool Start(DownloadFileObserver* observer, int format) = 0;
+    virtual void Stop() = 0;
+
+   protected:
+    friend class base::RefCountedThreadSafe<DownloadFileProvider>;
+    virtual ~DownloadFileProvider() {}
+  };
+
+  // Encapsulates the info about a file to be downloaded.
+  struct DownloadFileInfo {
+    FilePath filename;
+    uint64 size;
+    scoped_refptr<DownloadFileProvider> downloader;
+
+    DownloadFileInfo(const FilePath& filename,
+                     uint64 size,
+                     DownloadFileProvider* downloader)
+        : filename(filename),
+          size(size),
+          downloader(downloader) {}
+  };
+
   // Provider defines the platform specific part of OSExchangeData that
   // interacts with the native system.
   class Provider {
    public:
     Provider() {}
     virtual ~Provider() {}
 
     virtual void SetString(const std::wstring& data) = 0;
     virtual void SetURL(const GURL& url, const std::wstring& title) = 0;
     virtual void SetFilename(const std::wstring& full_path) = 0;
@@ skipping 12 matching lines @@
 
 #if defined(OS_WIN)
     virtual void SetFileContents(const std::wstring& filename,
                                  const std::string& file_contents) = 0;
     virtual void SetHtml(const std::wstring& html, const GURL& base_url) = 0;
     virtual bool GetFileContents(std::wstring* filename,
                                  std::string* file_contents) const = 0;
     virtual bool GetHtml(std::wstring* html, GURL* base_url) const = 0;
     virtual bool HasFileContents() const = 0;
     virtual bool HasHtml() const = 0;
+    virtual void SetDownloadFileInfo(DownloadFileInfo* download) = 0;
 #endif
   };
 
   OSExchangeData();
   // Creates an OSExchangeData with the specified provider. OSExchangeData
   // takes ownership of the supplied provider.
   explicit OSExchangeData(Provider* provider);
 
   ~OSExchangeData();
 
@@ skipping 53 matching lines @@
 #if defined(OS_WIN)
   // Adds the bytes of a file (CFSTR_FILECONTENTS and CFSTR_FILEDESCRIPTOR).
   void SetFileContents(const std::wstring& filename,
                        const std::string& file_contents);
   // Adds a snippet of HTML.  |html| is just raw html but this sets both
   // text/html and CF_HTML.
   void SetHtml(const std::wstring& html, const GURL& base_url);
   bool GetFileContents(std::wstring* filename,
                        std::string* file_contents) const;
   bool GetHtml(std::wstring* html, GURL* base_url) const;
+
+  // Adds a download file with full path (CF_HDROP).
+  void SetDownloadFileInfo(DownloadFileInfo* download);
 #endif
 
  private:
   // Creates the platform specific Provider.
   static Provider* CreateProvider();
 
   // Provides the actual data.
   scoped_ptr<Provider> provider_;
 
   DISALLOW_COPY_AND_ASSIGN(OSExchangeData);
 };
 
 #endif  // APP_OS_EXCHANGE_DATA_H_