From 5dd2c621327b68b5412e17fa49a932ff8f5690de Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@pdimov.com>
Date: Sat, 23 Nov 2002 12:47:38 +0000
Subject: [PATCH] weak_ptr converting constructor removed; operator< can now
 take different types to aid ownership tests.

[SVN r16376]
---
 include/boost/shared_ptr.hpp |  4 ++--
 include/boost/weak_ptr.hpp   | 25 ++++++-------------------
 shared_ptr_test.cpp          | 12 +++---------
 3 files changed, 11 insertions(+), 30 deletions(-)

diff --git a/include/boost/shared_ptr.hpp b/include/boost/shared_ptr.hpp
index 07ca043..6ffca27 100644
--- a/include/boost/shared_ptr.hpp
+++ b/include/boost/shared_ptr.hpp
@@ -272,7 +272,7 @@ public:
         pn.swap(other.pn);
     }
 
-    bool _internal_less(this_type const & rhs) const // implementation detail, never throws
+    template<class Y> bool _internal_less(shared_ptr<Y> const & rhs) const
     {
         return pn < rhs.pn;
     }
@@ -321,7 +321,7 @@ template<class T> inline bool operator!=(shared_ptr<T> const & a, shared_ptr<T>
 
 #endif
 
-template<class T> inline bool operator<(shared_ptr<T> const & a, shared_ptr<T> const & b)
+template<class T, class U> inline bool operator<(shared_ptr<T> const & a, shared_ptr<U> const & b)
 {
     return a._internal_less(b);
 }
diff --git a/include/boost/weak_ptr.hpp b/include/boost/weak_ptr.hpp
index cce5cb8..03e3800 100644
--- a/include/boost/weak_ptr.hpp
+++ b/include/boost/weak_ptr.hpp
@@ -45,7 +45,7 @@ public:
 
 
 //
-//  The simple implementation of the converting constructor:
+//  The "obvious" converting constructor implementation:
 //
 //  template<class Y>
 //  weak_ptr(weak_ptr<Y> const & r): px(r.px), pn(r.pn) // never throws
@@ -60,23 +60,10 @@ public:
 //  It is not possible to avoid spurious access violations since
 //  in multithreaded programs r.px may be invalidated at any point.
 //
-//  A safe conversion between weak_ptr<T> and weak_ptr<Y> must involve
-//  a temporary shared_ptr.
+//  A weak_ptr<T> can safely be obtained from a weak_ptr<U> by using
 //
-//  It is not yet clear whether the converting constructor should be
-//  present at all, or it's better to require an explicit make_shared call.
+//  weak_ptr<T> wpt = make_shared(wpu);
 //
-//  The only case for the converting constructor is the weak_ptr<T> -> weak_ptr<cv void>
-//  conversion.
-//
-
-    template<class Y>
-    weak_ptr(weak_ptr<Y> const & r) // never throws
-    {
-        shared_ptr<Y> tmp = make_shared(r);
-        px = tmp.px;
-        pn = tmp.pn;
-    }
 
     template<class Y>
     weak_ptr(shared_ptr<Y> const & r): px(r.px), pn(r.pn) // never throws
@@ -116,13 +103,13 @@ public:
         pn.swap(other.pn);
     }
 
-    void _internal_assign(T * px2, detail::shared_count const & pn2) // implementation detail
+    void _internal_assign(T * px2, detail::shared_count const & pn2)
     {
         px = px2;
         pn = pn2;
     }
 
-    bool _internal_less(this_type const & rhs) const // implementation detail, never throws
+    template<class Y> bool _internal_less(weak_ptr<Y> const & rhs) const
     {
         return pn < rhs.pn;
     }
@@ -144,7 +131,7 @@ private:
 
 };  // weak_ptr
 
-template<class T> inline bool operator<(weak_ptr<T> const & a, weak_ptr<T> const & b)
+template<class T, class U> inline bool operator<(weak_ptr<T> const & a, weak_ptr<U> const & b)
 {
     return a._internal_less(b);
 }
diff --git a/shared_ptr_test.cpp b/shared_ptr_test.cpp
index cbaaeed..99ba2de 100644
--- a/shared_ptr_test.cpp
+++ b/shared_ptr_test.cpp
@@ -773,11 +773,6 @@ void weak_ptr_constructor()
     catch(boost::bad_weak_ptr)
     {
     }
-
-    {
-        boost::weak_ptr<Y> wp2(wp);
-        boost::weak_ptr<X> wp3(wp);
-    }
 }
 
 void auto_ptr_constructor()
@@ -2256,13 +2251,13 @@ template<class T> void test_ne(T const & a, T const & b)
     BOOST_TEST(!(a < b && b < a));
 }
 
-void test_shared(boost::weak_ptr<void> const & a, boost::weak_ptr<void> const & b)
+template<class T, class U> void test_shared(boost::weak_ptr<T> const & a, boost::weak_ptr<U> const & b)
 {
     BOOST_TEST(!(a < b));
     BOOST_TEST(!(b < a));
 }
 
-void test_nonshared(boost::weak_ptr<void> const & a, boost::weak_ptr<void> const & b)
+template<class T, class U> void test_nonshared(boost::weak_ptr<T> const & a, boost::weak_ptr<U> const & b)
 {
     BOOST_TEST(a < b || b < a);
     BOOST_TEST(!(a < b && b < a));
@@ -2381,7 +2376,7 @@ void test()
         BOOST_TEST(wp3.use_count() == 1);
         test_shared(wp2, wp3);
 
-        weak_ptr<X> wp4(wp3);
+		weak_ptr<X> wp4 = boost::make_shared(wp3);
 
         BOOST_TEST(wp4.use_count() == 1);
         test_shared(wp2, wp4);
@@ -2390,7 +2385,6 @@ void test()
         test_is_zero(boost::make_shared(wp1));
 
         wp1 = p4;
-        wp1 = wp3;
         wp1 = wp2;
 
         BOOST_TEST(wp1.use_count() == 1);