Drag on linux

ui/base/x/selection_utils.h

 // Copyright (c) 2013 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 UI_BASE_X_SELECTION_UTILS_H_
 #define UI_BASE_X_SELECTION_UTILS_H_
 
 #include <X11/Xlib.h>
 
 // Get rid of a macro from Xlib.h that conflicts with Aura's RootWindow class.
 #undef RootWindow
 
 #include <map>
 
 #include "base/basictypes.h"
 #include "ui/base/clipboard/clipboard.h"
 #include "ui/base/ui_export.h"
 #include "ui/base/x/x11_atom_cache.h"
 
 namespace ui {
+class SelectionData;
 class X11AtomCache;
 
 extern const char kMimeTypeMozillaURL[];
 extern const char kString[];
 extern const char kText[];
 extern const char kUtf8String[];
 
 // Returns a list of all text atoms that we handle.
 UI_EXPORT std::vector< ::Atom> GetTextAtomsFrom(const X11AtomCache* atom_cache);
 
@@ skipping 11 matching lines @@
 class UI_EXPORT SelectionFormatMap {
  public:
   // Our internal data store, which we only expose through iterators.
   typedef std::map< ::Atom, std::pair<char*, size_t> > InternalMap;
   typedef std::map< ::Atom, std::pair<char*, size_t> >::const_iterator
       const_iterator;
 
   SelectionFormatMap();
   ~SelectionFormatMap();
 
   // Adds the selection in the format |atom|. Ownership of |data| is passed to

[sky, 2013/06/18 14:09:45]

The semantics you're adding here are confusing and error prone (Insert can take
the same data multiple times). If there a reason you aren't using a const
std::string&?

[Elliot Glaysher, 2013/06/18 20:28:17]

These semantics date back in some way or another to when we started supporting
clipboards in GTK (r4719). SelectionFormatMap is a fairly straightforward copy
of clipboard_gtk.cc's TargetMap.

AFAIU, the reasoning behind why things work like this is that |data| can be huge
and can be served multiple times, especially when you consider that image data
can go on the clipboard under multiple MIME types.

I think I could make this backed by a map of shared_ptr<std::string> instead,
but any refactoring here is going to require major overhauls of the clipboard
system, which we share this code with. Would you mind if I do that in a followup
patch?

   // us.
   void Insert(::Atom atom, char* data, size_t size);
 
+  // Returns the first of the requested_types or NULL if missing.
+  ui::SelectionData* GetFirstOf(
+      const std::vector< ::Atom>& requested_types) const;
+
+  // Returns all the selected types.
+  std::vector< ::Atom> GetTypes() const;
+
+  // Creates a copy of the selection data.
+  scoped_ptr<SelectionFormatMap> Clone() const;
+
   // Pass through to STL map. Only allow non-mutation access.
   const_iterator begin() const { return data_.begin(); }
   const_iterator end() const { return data_.end(); }
   const_iterator find(::Atom atom) const { return data_.find(atom); }
   size_t size() const { return data_.size(); }
 
  private:
   InternalMap data_;
 
   DISALLOW_COPY_AND_ASSIGN(SelectionFormatMap);
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 // A holder for data with optional X11 deletion semantics.
 class UI_EXPORT SelectionData {
  public:
   // |atom_cache| is still owned by caller.
-  explicit SelectionData(Display* x_display);
+  SelectionData();
   ~SelectionData();
 
   ::Atom type() const { return type_; }
   char* data() const { return data_; }
   size_t size() const { return size_; }
 
   void Set(::Atom type, char* data, size_t size, bool owned);
 
   // If |type_| is a string type, convert the data to UTF8 and return it.
   std::string GetText() const;
@@ skipping 13 matching lines @@
   bool owned_;
 
   X11AtomCache atom_cache_;
 
   DISALLOW_COPY_AND_ASSIGN(SelectionData);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_X_SELECTION_UTILS_H_