/thirdparty/breakpad/processor/scoped_ptr.h

  1//  (C) Copyright Greg Colvin and Beman Dawes 1998, 1999.
  2//  Copyright (c) 2001, 2002 Peter Dimov
  3//
  4//  Permission to copy, use, modify, sell and distribute this software
  5//  is granted provided this copyright notice appears in all copies.
  6//  This software is provided "as is" without express or implied
  7//  warranty, and with no claim as to its suitability for any purpose.
  8//
  9//  See http://www.boost.org/libs/smart_ptr/scoped_ptr.htm for documentation.
 10//
 11
 12//  scoped_ptr mimics a built-in pointer except that it guarantees deletion
 13//  of the object pointed to, either on destruction of the scoped_ptr or via
 14//  an explicit reset(). scoped_ptr is a simple solution for simple needs;
 15//  use shared_ptr or std::auto_ptr if your needs are more complex.
 16
 17//  *** NOTE ***
 18//  If your scoped_ptr is a class member of class FOO pointing to a 
 19//  forward declared type BAR (as shown below), then you MUST use a non-inlined 
 20//  version of the destructor.  The destructor of a scoped_ptr (called from
 21//  FOO's destructor) must have a complete definition of BAR in order to 
 22//  destroy it.  Example:
 23//
 24//  -- foo.h --
 25//  class BAR;
 26//
 27//  class FOO {
 28//   public:
 29//    FOO();
 30//    ~FOO();  // Required for sources that instantiate class FOO to compile!
 31//    
 32//   private:
 33//    scoped_ptr<BAR> bar_;
 34//  };
 35//
 36//  -- foo.cc --
 37//  #include "foo.h"
 38//  FOO::~FOO() {} // Empty, but must be non-inlined to FOO's class definition.
 39
 40//  scoped_ptr_malloc added by Google
 41//  When one of these goes out of scope, instead of doing a delete or
 42//  delete[], it calls free().  scoped_ptr_malloc<char> is likely to see
 43//  much more use than any other specializations.
 44
 45//  release() added by Google
 46//  Use this to conditionally transfer ownership of a heap-allocated object
 47//  to the caller, usually on method success.
 48
 49#ifndef PROCESSOR_SCOPED_PTR_H__
 50#define PROCESSOR_SCOPED_PTR_H__
 51
 52#include <cstddef>            // for std::ptrdiff_t
 53#include <assert.h>           // for assert
 54#include <stdlib.h>           // for free() decl
 55
 56namespace google_breakpad {
 57
 58template <typename T>
 59class scoped_ptr {
 60 private:
 61
 62  T* ptr;
 63
 64  scoped_ptr(scoped_ptr const &);
 65  scoped_ptr & operator=(scoped_ptr const &);
 66
 67 public:
 68
 69  typedef T element_type;
 70
 71  explicit scoped_ptr(T* p = 0): ptr(p) {}
 72
 73  ~scoped_ptr() {
 74    typedef char type_must_be_complete[sizeof(T)];
 75    delete ptr;
 76  }
 77
 78  void reset(T* p = 0) {
 79    typedef char type_must_be_complete[sizeof(T)];
 80
 81    if (ptr != p) {
 82      delete ptr;
 83      ptr = p;
 84    }
 85  }
 86
 87  T& operator*() const {
 88    assert(ptr != 0);
 89    return *ptr;
 90  }
 91
 92  T* operator->() const  {
 93    assert(ptr != 0);
 94    return ptr;
 95  }
 96
 97  bool operator==(T* p) const {
 98    return ptr == p;
 99  }
100
101  bool operator!=(T* p) const {
102    return ptr != p;
103  }
104
105  T* get() const  {
106    return ptr;
107  }
108
109  void swap(scoped_ptr & b) {
110    T* tmp = b.ptr;
111    b.ptr = ptr;
112    ptr = tmp;
113  }
114
115  T* release() {
116    T* tmp = ptr;
117    ptr = 0;
118    return tmp;
119  }
120
121 private:
122
123  // no reason to use these: each scoped_ptr should have its own object
124  template <typename U> bool operator==(scoped_ptr<U> const& p) const;
125  template <typename U> bool operator!=(scoped_ptr<U> const& p) const;
126};
127
128template<typename T> inline
129void swap(scoped_ptr<T>& a, scoped_ptr<T>& b) {
130  a.swap(b);
131}
132
133template<typename T> inline
134bool operator==(T* p, const scoped_ptr<T>& b) {
135  return p == b.get();
136}
137
138template<typename T> inline
139bool operator!=(T* p, const scoped_ptr<T>& b) {
140  return p != b.get();
141}
142
143//  scoped_array extends scoped_ptr to arrays. Deletion of the array pointed to
144//  is guaranteed, either on destruction of the scoped_array or via an explicit
145//  reset(). Use shared_array or std::vector if your needs are more complex.
146
147template<typename T>
148class scoped_array {
149 private:
150
151  T* ptr;
152
153  scoped_array(scoped_array const &);
154  scoped_array & operator=(scoped_array const &);
155
156 public:
157
158  typedef T element_type;
159
160  explicit scoped_array(T* p = 0) : ptr(p) {}
161
162  ~scoped_array() {
163    typedef char type_must_be_complete[sizeof(T)];
164    delete[] ptr;
165  }
166
167  void reset(T* p = 0) {
168    typedef char type_must_be_complete[sizeof(T)];
169
170    if (ptr != p) {
171      delete [] ptr;
172      ptr = p;
173    }
174  }
175
176  T& operator[](std::ptrdiff_t i) const {
177    assert(ptr != 0);
178    assert(i >= 0);
179    return ptr[i];
180  }
181
182  bool operator==(T* p) const {
183    return ptr == p;
184  }
185
186  bool operator!=(T* p) const {
187    return ptr != p;
188  }
189
190  T* get() const {
191    return ptr;
192  }
193
194  void swap(scoped_array & b) {
195    T* tmp = b.ptr;
196    b.ptr = ptr;
197    ptr = tmp;
198  }
199
200  T* release() {
201    T* tmp = ptr;
202    ptr = 0;
203    return tmp;
204  }
205
206 private:
207
208  // no reason to use these: each scoped_array should have its own object
209  template <typename U> bool operator==(scoped_array<U> const& p) const;
210  template <typename U> bool operator!=(scoped_array<U> const& p) const;
211};
212
213template<class T> inline
214void swap(scoped_array<T>& a, scoped_array<T>& b) {
215  a.swap(b);
216}
217
218template<typename T> inline
219bool operator==(T* p, const scoped_array<T>& b) {
220  return p == b.get();
221}
222
223template<typename T> inline
224bool operator!=(T* p, const scoped_array<T>& b) {
225  return p != b.get();
226}
227
228
229// This class wraps the c library function free() in a class that can be
230// passed as a template argument to scoped_ptr_malloc below.
231class ScopedPtrMallocFree {
232 public:
233  inline void operator()(void* x) const {
234    free(x);
235  }
236};
237
238// scoped_ptr_malloc<> is similar to scoped_ptr<>, but it accepts a
239// second template argument, the functor used to free the object.
240
241template<typename T, typename FreeProc = ScopedPtrMallocFree>
242class scoped_ptr_malloc {
243 private:
244
245  T* ptr;
246
247  scoped_ptr_malloc(scoped_ptr_malloc const &);
248  scoped_ptr_malloc & operator=(scoped_ptr_malloc const &);
249
250 public:
251
252  typedef T element_type;
253
254  explicit scoped_ptr_malloc(T* p = 0): ptr(p) {}
255
256  ~scoped_ptr_malloc() {
257    typedef char type_must_be_complete[sizeof(T)];
258    free_((void*) ptr);
259  }
260
261  void reset(T* p = 0) {
262    typedef char type_must_be_complete[sizeof(T)];
263
264    if (ptr != p) {
265      free_((void*) ptr);
266      ptr = p;
267    }
268  }
269
270  T& operator*() const {
271    assert(ptr != 0);
272    return *ptr;
273  }
274
275  T* operator->() const {
276    assert(ptr != 0);
277    return ptr;
278  }
279
280  bool operator==(T* p) const {
281    return ptr == p;
282  }
283
284  bool operator!=(T* p) const {
285    return ptr != p;
286  }
287
288  T* get() const {
289    return ptr;
290  }
291
292  void swap(scoped_ptr_malloc & b) {
293    T* tmp = b.ptr;
294    b.ptr = ptr;
295    ptr = tmp;
296  }
297
298  T* release() {
299    T* tmp = ptr;
300    ptr = 0;
301    return tmp;
302  }
303
304 private:
305
306  // no reason to use these: each scoped_ptr_malloc should have its own object
307  template <typename U, typename GP>
308  bool operator==(scoped_ptr_malloc<U, GP> const& p) const;
309  template <typename U, typename GP>
310  bool operator!=(scoped_ptr_malloc<U, GP> const& p) const;
311
312  static FreeProc const free_;
313};
314
315template<typename T, typename FP>
316FP const scoped_ptr_malloc<T,FP>::free_ = FP();
317
318template<typename T, typename FP> inline
319void swap(scoped_ptr_malloc<T,FP>& a, scoped_ptr_malloc<T,FP>& b) {
320  a.swap(b);
321}
322
323template<typename T, typename FP> inline
324bool operator==(T* p, const scoped_ptr_malloc<T,FP>& b) {
325  return p == b.get();
326}
327
328template<typename T, typename FP> inline
329bool operator!=(T* p, const scoped_ptr_malloc<T,FP>& b) {
330  return p != b.get();
331}
332
333}  // namespace google_breakpad
334
335#endif  // PROCESSOR_SCOPED_PTR_H__