mirror of
https://github.com/boostorg/smart_ptr.git
synced 2026-05-05 12:24:17 +02:00
New smart pointer documentation. Related clean-up of the smart pointer
library. Changing includes to include the new individual smart pointer headers. Replacing old smart pointer library with an include of the new smart pointer headers. Simplify ifdefs that involve the member templates macros now that BOOST_MSVC6_MEMBER_TEMPLATES is also guaranteed to bet set for platforms that have full member templates. [SVN r12647]
This commit is contained in:
Darin Adler
+6
-399
@@ -1,402 +1,9 @@
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// Boost smart_ptr.hpp header file -----------------------------------------//
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// (C) Copyright Greg Colvin and Beman Dawes 1998, 1999. Permission to copy,
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// use, modify, sell and distribute this software is granted provided this
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// copyright notice appears in all copies. This software is provided "as is"
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// without express or implied warranty, and with no claim as to its
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// suitability for any purpose.
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// See http://www.boost.org for most recent version including documentation.
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// Revision History
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// 6 Jul 01 Reorder shared_ptr code so VC++ 6 member templates work, allowing
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// polymorphic pointers to now work with that compiler (Gary Powell)
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// 21 May 01 Require complete type where incomplete type is unsafe.
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// (suggested by Vladimir Prus)
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// 21 May 01 operator= fails if operand transitively owned by *this, as in a
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// linked list (report by Ken Johnson, fix by Beman Dawes)
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// 21 Jan 01 Suppress some useless warnings with MSVC (David Abrahams)
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// 19 Oct 00 Make shared_ptr ctor from auto_ptr explicit. (Robert Vugts)
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// 24 Jul 00 Change throw() to // never throws. See lib guidelines
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// Exception-specification rationale. (Beman Dawes)
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// 22 Jun 00 Remove #if continuations to fix GCC 2.95.2 problem (Beman Dawes)
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// 1 Feb 00 Additional shared_ptr BOOST_NO_MEMBER_TEMPLATES workarounds
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// (Dave Abrahams)
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// 31 Dec 99 Condition tightened for no member template friend workaround
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// (Dave Abrahams)
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// 30 Dec 99 Moved BOOST_NMEMBER_TEMPLATES compatibility code to config.hpp
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// (Dave Abrahams)
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// 30 Nov 99 added operator ==, operator !=, and std::swap and std::less
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// specializations for shared types (Darin Adler)
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// 11 Oct 99 replaced op[](int) with op[](std::size_t) (Ed Brey, Valentin
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// Bonnard), added shared_ptr workaround for no member template
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// friends (Matthew Langston)
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// 25 Sep 99 added shared_ptr::swap and shared_array::swap (Luis Coelho).
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// 20 Jul 99 changed name to smart_ptr.hpp, #include <boost/config.hpp>,
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// #include <boost/utility.hpp> and use boost::noncopyable
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// 17 May 99 remove scoped_array and shared_array operator*() as
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// unnecessary (Beman Dawes)
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// 14 May 99 reorder code so no effects when bad_alloc thrown (Abrahams/Dawes)
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// 13 May 99 remove certain throw() specifiers to avoid generated try/catch
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// code cost (Beman Dawes)
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// 11 May 99 get() added, conversion to T* placed in macro guard (Valentin
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// Bonnard, Dave Abrahams, and others argued for elimination
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// of the automatic conversion)
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// 28 Apr 99 #include <memory> fix (Valentin Bonnard)
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// 28 Apr 99 rename transfer() to share() for clarity (Dave Abrahams)
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// 28 Apr 99 remove unsafe shared_array template conversions(Valentin Bonnard)
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// 28 Apr 99 p(r) changed to p(r.px) for clarity (Dave Abrahams)
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// 21 Apr 99 reset() self assignment fix (Valentin Bonnard)
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// 21 Apr 99 dispose() provided to improve clarity (Valentin Bonnard)
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// 27 Apr 99 leak when new throws fixes (Dave Abrahams)
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// 21 Oct 98 initial Version (Greg Colvin/Beman Dawes)
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#ifndef BOOST_SMART_PTR_HPP
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#define BOOST_SMART_PTR_HPP
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#include <boost/config.hpp> // for broken compiler workarounds
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#include <cstddef> // for std::size_t
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#include <memory> // for std::auto_ptr
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#include <algorithm> // for std::swap
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#include <boost/utility.hpp> // for boost::noncopyable, checked_delete, checked_array_delete
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#include <functional> // for std::less
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#include <boost/static_assert.hpp> // for BOOST_STATIC_ASSERT
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#ifdef BOOST_MSVC // moved here to work around VC++ compiler crash
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# pragma warning(push)
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# pragma warning(disable:4284) // return type for 'identifier::operator->' is not a UDT or reference to a UDT. Will produce errors if applied using infix notation
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#endif
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namespace boost {
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// scoped_ptr --------------------------------------------------------------//
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// scoped_ptr mimics a built-in pointer except that it guarantees deletion
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// of the object pointed to, either on destruction of the scoped_ptr or via
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// an explicit reset(). scoped_ptr is a simple solution for simple needs;
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// see shared_ptr (below) or std::auto_ptr if your needs are more complex.
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template<typename T> class scoped_ptr : noncopyable {
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T* ptr;
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public:
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typedef T element_type;
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explicit scoped_ptr( T* p=0 ) : ptr(p) {} // never throws
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~scoped_ptr() { checked_delete(ptr); }
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void reset( T* p=0 ) { if ( ptr != p ) { checked_delete(ptr); ptr = p; } }
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T& operator*() const { return *ptr; } // never throws
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T* operator->() const { return ptr; } // never throws
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T* get() const { return ptr; } // never throws
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#ifdef BOOST_SMART_PTR_CONVERSION
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// get() is safer! Define BOOST_SMART_PTR_CONVERSION at your own risk!
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operator T*() const { return ptr; } // never throws
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#endif
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}; // scoped_ptr
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// scoped_array ------------------------------------------------------------//
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// scoped_array extends scoped_ptr to arrays. Deletion of the array pointed to
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// is guaranteed, either on destruction of the scoped_array or via an explicit
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// reset(). See shared_array or std::vector if your needs are more complex.
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template<typename T> class scoped_array : noncopyable {
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T* ptr;
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public:
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typedef T element_type;
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explicit scoped_array( T* p=0 ) : ptr(p) {} // never throws
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~scoped_array() { checked_array_delete(ptr); }
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void reset( T* p=0 ) { if ( ptr != p )
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{checked_array_delete(ptr); ptr=p;} }
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T* get() const { return ptr; } // never throws
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#ifdef BOOST_SMART_PTR_CONVERSION
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// get() is safer! Define BOOST_SMART_PTR_CONVERSION at your own risk!
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operator T*() const { return ptr; } // never throws
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#else
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T& operator[](std::size_t i) const { return ptr[i]; } // never throws
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#endif
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}; // scoped_array
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// shared_ptr --------------------------------------------------------------//
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// An enhanced relative of scoped_ptr with reference counted copy semantics.
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// The object pointed to is deleted when the last shared_ptr pointing to it
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// is destroyed or reset.
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template<typename T> class shared_ptr {
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public:
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typedef T element_type;
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explicit shared_ptr(T* p =0) : px(p) {
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try { pn = new long(1); } // fix: prevent leak if new throws
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catch (...) { checked_delete(p); throw; }
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}
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~shared_ptr() { dispose(); }
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#if !defined( BOOST_NO_MEMBER_TEMPLATES ) || defined (BOOST_MSVC6_MEMBER_TEMPLATES)
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template<typename Y>
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shared_ptr(const shared_ptr<Y>& r) : px(r.px) { // never throws
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++*(pn = r.pn);
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}
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#ifndef BOOST_NO_AUTO_PTR
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template<typename Y>
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explicit shared_ptr(std::auto_ptr<Y>& r) {
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pn = new long(1); // may throw
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px = r.release(); // fix: moved here to stop leak if new throws
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}
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#endif
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template<typename Y>
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shared_ptr& operator=(const shared_ptr<Y>& r) {
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share(r.px,r.pn);
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return *this;
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}
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#ifndef BOOST_NO_AUTO_PTR
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template<typename Y>
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shared_ptr& operator=(std::auto_ptr<Y>& r) {
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// code choice driven by guarantee of "no effect if new throws"
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if (*pn == 1) { checked_delete(px); }
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else { // allocate new reference counter
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long * tmp = new long(1); // may throw
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--*pn; // only decrement once danger of new throwing is past
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pn = tmp;
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} // allocate new reference counter
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px = r.release(); // fix: moved here so doesn't leak if new throws
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return *this;
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}
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#endif
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#else
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#ifndef BOOST_NO_AUTO_PTR
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explicit shared_ptr(std::auto_ptr<T>& r) {
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pn = new long(1); // may throw
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px = r.release(); // fix: moved here to stop leak if new throws
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}
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shared_ptr& operator=(std::auto_ptr<T>& r) {
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// code choice driven by guarantee of "no effect if new throws"
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if (*pn == 1) { checked_delete(px); }
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else { // allocate new reference counter
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long * tmp = new long(1); // may throw
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--*pn; // only decrement once danger of new throwing is past
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pn = tmp;
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} // allocate new reference counter
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px = r.release(); // fix: moved here so doesn't leak if new throws
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return *this;
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}
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#endif
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#endif
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// The assignment operator and the copy constructor must come after
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// the templated versions for MSVC6 to work. (Gary Powell)
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shared_ptr(const shared_ptr& r) : px(r.px) { ++*(pn = r.pn); } // never throws
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shared_ptr& operator=(const shared_ptr& r) {
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share(r.px,r.pn);
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return *this;
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}
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void reset(T* p=0) {
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if ( px == p ) return; // fix: self-assignment safe
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if (--*pn == 0) { checked_delete(px); }
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else { // allocate new reference counter
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try { pn = new long; } // fix: prevent leak if new throws
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catch (...) {
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++*pn; // undo effect of --*pn above to meet effects guarantee
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checked_delete(p);
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throw;
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} // catch
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} // allocate new reference counter
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*pn = 1;
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px = p;
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} // reset
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T& operator*() const { return *px; } // never throws
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T* operator->() const { return px; } // never throws
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T* get() const { return px; } // never throws
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#ifdef BOOST_SMART_PTR_CONVERSION
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// get() is safer! Define BOOST_SMART_PTR_CONVERSION at your own risk!
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operator T*() const { return px; } // never throws
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#endif
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long use_count() const { return *pn; } // never throws
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bool unique() const { return *pn == 1; } // never throws
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void swap(shared_ptr<T>& other) // never throws
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{ std::swap(px,other.px); std::swap(pn,other.pn); }
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// Tasteless as this may seem, making all members public allows member templates
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// to work in the absence of member template friends. (Matthew Langston)
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// Don't split this line into two; that causes problems for some GCC 2.95.2 builds
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#if ( defined(BOOST_NO_MEMBER_TEMPLATES) && !defined(BOOST_MSVC6_MEMBER_TEMPLATES) ) || !defined( BOOST_NO_MEMBER_TEMPLATE_FRIENDS )
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private:
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#endif
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T* px; // contained pointer
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long* pn; // ptr to reference counter
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// Don't split this line into two; that causes problems for some GCC 2.95.2 builds
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#if !defined( BOOST_NO_MEMBER_TEMPLATES ) && !defined( BOOST_NO_MEMBER_TEMPLATE_FRIENDS )
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template<typename Y> friend class shared_ptr;
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#endif
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void dispose() { if (--*pn == 0) { checked_delete(px); delete pn; } }
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void share(T* rpx, long* rpn) {
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if (pn != rpn) { // Q: why not px != rpx? A: fails when both == 0
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++*rpn; // done before dispose() in case rpn transitively
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// dependent on *this (bug reported by Ken Johnson)
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dispose();
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px = rpx;
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pn = rpn;
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}
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} // share
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}; // shared_ptr
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template<typename T, typename U>
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inline bool operator==(const shared_ptr<T>& a, const shared_ptr<U>& b)
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{ return a.get() == b.get(); }
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template<typename T, typename U>
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inline bool operator!=(const shared_ptr<T>& a, const shared_ptr<U>& b)
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{ return a.get() != b.get(); }
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// shared_array ------------------------------------------------------------//
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// shared_array extends shared_ptr to arrays.
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// The array pointed to is deleted when the last shared_array pointing to it
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// is destroyed or reset.
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template<typename T> class shared_array {
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public:
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typedef T element_type;
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explicit shared_array(T* p =0) : px(p) {
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try { pn = new long(1); } // fix: prevent leak if new throws
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catch (...) { checked_array_delete(p); throw; }
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}
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shared_array(const shared_array& r) : px(r.px) // never throws
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{ ++*(pn = r.pn); }
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~shared_array() { dispose(); }
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shared_array& operator=(const shared_array& r) {
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if (pn != r.pn) { // Q: why not px != r.px? A: fails when both px == 0
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++*r.pn; // done before dispose() in case r.pn transitively
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// dependent on *this (bug reported by Ken Johnson)
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dispose();
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px = r.px;
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pn = r.pn;
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}
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return *this;
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} // operator=
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void reset(T* p=0) {
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if ( px == p ) return; // fix: self-assignment safe
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if (--*pn == 0) { checked_array_delete(px); }
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else { // allocate new reference counter
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try { pn = new long; } // fix: prevent leak if new throws
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catch (...) {
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++*pn; // undo effect of --*pn above to meet effects guarantee
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checked_array_delete(p);
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throw;
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} // catch
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} // allocate new reference counter
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*pn = 1;
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px = p;
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} // reset
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T* get() const { return px; } // never throws
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#ifdef BOOST_SMART_PTR_CONVERSION
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// get() is safer! Define BOOST_SMART_PTR_CONVERSION at your own risk!
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operator T*() const { return px; } // never throws
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#else
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T& operator[](std::size_t i) const { return px[i]; } // never throws
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#endif
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long use_count() const { return *pn; } // never throws
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bool unique() const { return *pn == 1; } // never throws
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void swap(shared_array<T>& other) // never throws
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{ std::swap(px,other.px); std::swap(pn,other.pn); }
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private:
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T* px; // contained pointer
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long* pn; // ptr to reference counter
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void dispose() { if (--*pn == 0) { checked_array_delete(px); delete pn; } }
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}; // shared_array
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template<typename T>
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inline bool operator==(const shared_array<T>& a, const shared_array<T>& b)
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{ return a.get() == b.get(); }
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template<typename T>
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inline bool operator!=(const shared_array<T>& a, const shared_array<T>& b)
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{ return a.get() != b.get(); }
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} // namespace boost
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// specializations for things in namespace std -----------------------------//
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#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
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namespace std {
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// Specialize std::swap to use the fast, non-throwing swap that's provided
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// as a member function instead of using the default algorithm which creates
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// a temporary and uses assignment.
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template<typename T>
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inline void swap(boost::shared_ptr<T>& a, boost::shared_ptr<T>& b)
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{ a.swap(b); }
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template<typename T>
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inline void swap(boost::shared_array<T>& a, boost::shared_array<T>& b)
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{ a.swap(b); }
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// Specialize std::less so we can use shared pointers and arrays as keys in
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// associative collections.
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// It's still a controversial question whether this is better than supplying
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// a full range of comparison operators (<, >, <=, >=).
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template<typename T>
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struct less< boost::shared_ptr<T> >
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: binary_function<boost::shared_ptr<T>, boost::shared_ptr<T>, bool>
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{
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bool operator()(const boost::shared_ptr<T>& a,
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const boost::shared_ptr<T>& b) const
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{ return std::less<T*>()(a.get(),b.get()); }
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};
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template<typename T>
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struct less< boost::shared_array<T> >
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: binary_function<boost::shared_array<T>, boost::shared_array<T>, bool>
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{
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bool operator()(const boost::shared_array<T>& a,
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const boost::shared_array<T>& b) const
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{ return std::less<T*>()(a.get(),b.get()); }
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};
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} // namespace std
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#endif // ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
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#ifdef BOOST_MSVC
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# pragma warning(pop)
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#endif
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#endif // BOOST_SMART_PTR_HPP
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// For compatibility, this header includes the header for the four "classic"
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// smart pointer class templates.
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#include <boost/scoped_ptr.hpp>
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#include <boost/scoped_array.hpp>
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#include <boost/shared_ptr.hpp>
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#include <boost/shared_array.hpp>
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