include/comphelper/weakbag.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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   9  * This file incorporates work covered by the following license notice:
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  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #ifndef INCLUDED_COMPHELPER_WEAKBAG_HXX
  21 #define INCLUDED_COMPHELPER_WEAKBAG_HXX
  22
  23 #include <sal/config.h>
  24
  25 #include <vector>
  26 #include <com/sun/star/uno/Reference.h>
  27 #include <cppuhelper/weakref.hxx>
  28 #include <osl/diagnose.h>
  29
  30 namespace comphelper {
  31
  32 /**
  33    A bag of UNO weak references.
  34 */
  35 template< typename T > class WeakBag {
  36 public:
  37     /**
  38        Add a new weak reference.
  39
  40        The implementation keeps the amount of memory consumed linear in the
  41        number of living references added, not linear in the number of total
  42        references added.
  43
  44        @param e
  45        a non-null reference.
  46     */
  47     void add(css::uno::Reference< T > const & e) {
  48         OSL_ASSERT(e.is());
  49         for (auto i = m_list.begin(); i != m_list.end();) {
  50             if (css::uno::Reference< T >(*i).is()) {
  51                 ++i;
  52             } else {
  53                 i = m_list.erase(i);
  54             }
  55         }
  56         m_list.push_back(css::uno::WeakReference< T >(e));
  57     }
  58
  59     /**
  60        Remove a living reference.
  61
  62        @return
  63        a living reference, or null if there are none.
  64     */
  65     css::uno::Reference< T > remove() {
  66         while (!m_list.empty()) {
  67             css::uno::Reference< T > r(m_list.back());
  68             m_list.pop_back();
  69             if (r.is()) {
  70                 return r;
  71             }
  72         }
  73         return css::uno::Reference< T >();
  74     }
  75
  76 private:
  77     std::vector< css::uno::WeakReference< T > > m_list;
  78 };
  79
  80 }
  81
  82 #endif
  83
  84 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */