src/base/TidyPointer.h

   1 /*
   2  * Copyright (C) 1996-2015 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID_BASE_TIDYPOINTER_H
  10 #define SQUID_BASE_TIDYPOINTER_H
  11
  12 /**
  13  * A pointer that deletes the object it points to when the pointer's owner or
  14  * context is gone. Similar to std::auto_ptr but without confusing assignment
  15  * and with a customizable cleanup method. Prevents memory leaks in
  16  * the presence of exceptions and processing short cuts.
  17 */
  18 template <typename T, void (*DeAllocator)(T *t)> class TidyPointer
  19 {
  20 public:
  21     /// Delete callback.
  22     typedef void DCB (T *t);
  23     TidyPointer(T *t = NULL)
  24         :   raw(t) {}
  25 public:
  26     bool operator !() const { return !raw; }
  27     /// Returns raw and possibly NULL pointer
  28     T *get() const { return raw; }
  29     /// Address of the raw pointer, for pointer-setting functions
  30     T **addr() { return &raw; }
  31     /// Reset raw pointer - delete last one and save new one.
  32     void reset(T *t) {
  33         deletePointer();
  34         raw = t;
  35     }
  36
  37     /// Forget the raw pointer without freeing it. Become a nil pointer.
  38     T *release() {
  39         T *ret = raw;
  40         raw = NULL;
  41         return ret;
  42     }
  43     /// Deallocate raw pointer.
  44     ~TidyPointer() {
  45         deletePointer();
  46     }
  47 private:
  48     /// Forbidden copy constructor.
  49     TidyPointer(TidyPointer<T, DeAllocator> const &);
  50     /// Forbidden assigment operator.
  51     TidyPointer <T, DeAllocator> & operator = (TidyPointer<T, DeAllocator> const &);
  52     /// Deallocate raw pointer. Become a nil pointer.
  53     void deletePointer() {
  54         if (raw) {
  55             DeAllocator(raw);
  56         }
  57         raw = NULL;
  58     }
  59     T *raw; ///< pointer to T object or NULL
  60 };
  61
  62 /// DeAllocator for pointers that need free(3) from the std C library
  63 template<typename T> void tidyFree(T *p)
  64 {
  65     xfree(p);
  66 }
  67
  68 #endif // SQUID_BASE_TIDYPOINTER_H
  69