ui/gfx/x/x11_atom_cache.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_GFX_X_X11_ATOM_CACHE_H_
   6 #define UI_GFX_X_X11_ATOM_CACHE_H_
   7
   8 #include <map>
   9 #include <string>
  10
  11 #include "base/basictypes.h"
  12 #include "ui/gfx/gfx_export.h"
  13
  14 typedef unsigned long Atom;
  15 typedef struct _XDisplay XDisplay;
  16
  17 namespace ui {
  18
  19 // Pre-caches all Atoms on first use to minimize roundtrips to the X11
  20 // server. By default, GetAtom() will CHECK() that atoms accessed through
  21 // GetAtom() were passed to the constructor, but this behaviour can be changed
  22 // with allow_uncached_atoms().
  23 class GFX_EXPORT X11AtomCache {
  24  public:
  25   // Preinterns the NULL terminated list of string |to_cache_ on |xdisplay|.
  26   X11AtomCache(XDisplay* xdisplay, const char** to_cache);
  27   ~X11AtomCache();
  28
  29   // Returns the pre-interned Atom without having to go to the x server.
  30   Atom GetAtom(const char*) const;
  31
  32   // When an Atom isn't in the list of items we've cached, we should look it
  33   // up, cache it locally, and then return the result.
  34   void allow_uncached_atoms() { uncached_atoms_allowed_ = true; }
  35
  36  private:
  37   XDisplay* xdisplay_;
  38
  39   bool uncached_atoms_allowed_;
  40
  41   mutable std::map<std::string, Atom> cached_atoms_;
  42
  43   DISALLOW_COPY_AND_ASSIGN(X11AtomCache);
  44 };
  45
  46 }  // namespace ui
  47
  48 #endif  // UI_GFX_X_X11_ATOM_CACHE_H_