Re: New istreambuf_iterator debug check

[Jonathan Wakely]

On 24/01/18 17:39 +0100, François Dumont wrote:

Hi

    I'd like to propose this new debug check. Comparing with non-eos 
istreambuf_iterator sounds like an obvious coding mistake.


Agreed, but that doesn't mean we can terminate the process. It's still
valid C++, even though it's probably not what the author intended to do.

Re: New istreambuf_iterator debug check

[Petr Ovtchenkov]

On Wed, 24 Jan 2018 21:34:48 +0100
François Dumont  wrote:

> On 24/01/2018 18:53, Petr Ovtchenkov wrote:
> > On Wed, 24 Jan 2018 17:39:59 +0100
> > François Dumont  wrote:
> >
> >> Hi
> >>
> >>       I'd like to propose this new debug check. Comparing with non-eos
> >> istreambuf_iterator sounds like an obvious coding mistake.
> >>
> >>       I propose it despite the stage 1 as it is just a new debug check,
> >> it doesn't impact the lib in normal mode.
> >>
> >>       Tested under Linux x86_64, ok to commit ?
> >>
> >> François
> >>
> > bool
> > equal(const istreambuf_iterator& __b) const
> > -  { return _M_at_eof() == __b._M_at_eof(); }
> > +  {
> > +   bool __this_at_eof = _M_at_eof();
> > +   bool __b_at_eof = __b._M_at_eof();
> > +
> > +   __glibcxx_requires_cond(__this_at_eof || __b_at_eof, _M_message(
> > + "Abnormal comparison to non-end-of-stream istreambuf_iterator"));
> > +   return __this_at_eof == __b_at_eof;
> > +  }
> >
> > Looks strange for me. It is legal and possible that istreambuf_iterator
> > will be in EOF state.
> >
> Sure, but consider rather the associated 3_neg.cc showing the debug 
> check purpose:
> 
>    cistreambuf_iter it1(istrs), it2(istrs);
>    it1 == it2; // No sens
> 

This is what author want to say.

Neveretheless, __glibcxx_requires_cond(__this_at_eof || __b_at_eof, ...
in equal looks bogus for me.

--

  - ptr

Re: New istreambuf_iterator debug check

[François Dumont]

On 24/01/2018 18:53, Petr Ovtchenkov wrote:

On Wed, 24 Jan 2018 17:39:59 +0100
François Dumont  wrote:


Hi

      I'd like to propose this new debug check. Comparing with non-eos
istreambuf_iterator sounds like an obvious coding mistake.

      I propose it despite the stage 1 as it is just a new debug check,
it doesn't impact the lib in normal mode.

      Tested under Linux x86_64, ok to commit ?

François


bool
equal(const istreambuf_iterator& __b) const
-  { return _M_at_eof() == __b._M_at_eof(); }
+  {
+   bool __this_at_eof = _M_at_eof();
+   bool __b_at_eof = __b._M_at_eof();
+
+   __glibcxx_requires_cond(__this_at_eof || __b_at_eof, _M_message(
+ "Abnormal comparison to non-end-of-stream istreambuf_iterator"));
+   return __this_at_eof == __b_at_eof;
+  }

Looks strange for me. It is legal and possible that istreambuf_iterator
will be in EOF state.

Sure, but consider rather the associated 3_neg.cc showing the debug 
check purpose:


  cistreambuf_iter it1(istrs), it2(istrs);
  it1 == it2; // No sens

Re: New istreambuf_iterator debug check

[Petr Ovtchenkov]

On Wed, 24 Jan 2018 17:39:59 +0100
François Dumont  wrote:

> Hi
> 
>      I'd like to propose this new debug check. Comparing with non-eos 
> istreambuf_iterator sounds like an obvious coding mistake.
> 
>      I propose it despite the stage 1 as it is just a new debug check, 
> it doesn't impact the lib in normal mode.
> 
>      Tested under Linux x86_64, ok to commit ?
> 
> François
> 

   bool
   equal(const istreambuf_iterator& __b) const
-  { return _M_at_eof() == __b._M_at_eof(); }
+  {
+   bool __this_at_eof = _M_at_eof();
+   bool __b_at_eof = __b._M_at_eof();
+
+   __glibcxx_requires_cond(__this_at_eof || __b_at_eof, _M_message(
+ "Abnormal comparison to non-end-of-stream istreambuf_iterator"));
+   return __this_at_eof == __b_at_eof;
+  }

Looks strange for me. It is legal and possible that istreambuf_iterator
will be in EOF state.

--

  - ptr

New istreambuf_iterator debug check

[François Dumont]

Hi

    I'd like to propose this new debug check. Comparing with non-eos 
istreambuf_iterator sounds like an obvious coding mistake.


    I propose it despite the stage 1 as it is just a new debug check, 
it doesn't impact the lib in normal mode.


    Tested under Linux x86_64, ok to commit ?

François

diff --git a/libstdc++-v3/include/bits/streambuf_iterator.h b/libstdc++-v3/include/bits/streambuf_iterator.h
index 292ef3a..2e46771 100644
--- a/libstdc++-v3/include/bits/streambuf_iterator.h
+++ b/libstdc++-v3/include/bits/streambuf_iterator.h
@@ -174,7 +174,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   /// Return true both iterators are end or both are not end.
   bool
   equal(const istreambuf_iterator& __b) const
-  { return _M_at_eof() == __b._M_at_eof(); }
+  {
+	bool __this_at_eof = _M_at_eof();
+	bool __b_at_eof = __b._M_at_eof();
+
+	__glibcxx_requires_cond(__this_at_eof || __b_at_eof, _M_message(
+	  "Abnormal comparison to non-end-of-stream istreambuf_iterator"));
+	return __this_at_eof == __b_at_eof;
+  }
 
 private:
   int_type
diff --git a/libstdc++-v3/testsuite/24_iterators/istreambuf_iterator/1.cc b/libstdc++-v3/testsuite/24_iterators/istreambuf_iterator/1.cc
new file mode 100644
index 000..bb2e6f8
--- /dev/null
+++ b/libstdc++-v3/testsuite/24_iterators/istreambuf_iterator/1.cc
@@ -0,0 +1,50 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// .
+
+#include 
+#include 
+
+#include 
+
+void test01()
+{
+  std::istringstream istrs("123456789");
+  typedef std::istreambuf_iterator cistreambuf_iter;
+
+  cistreambuf_iter it(istrs);
+  cistreambuf_iter eof;
+  VERIFY( !it.equal(eof) );
+  VERIFY( !eof.equal(it) );
+  VERIFY( it != eof );
+  VERIFY( eof != it );
+}
+
+void test02()
+{
+  typedef std::istreambuf_iterator cistreambuf_iter;
+
+  cistreambuf_iter eof;
+  VERIFY( eof.equal(eof) );
+  VERIFY( eof == eof );
+}
+
+int main()
+{
+  test01();
+  test02();
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/24_iterators/istreambuf_iterator/2.cc b/libstdc++-v3/testsuite/24_iterators/istreambuf_iterator/2.cc
index 3fe1cf1..47a1a00 100644
--- a/libstdc++-v3/testsuite/24_iterators/istreambuf_iterator/2.cc
+++ b/libstdc++-v3/testsuite/24_iterators/istreambuf_iterator/2.cc
@@ -47,7 +47,10 @@ void test02(void)
 
   cistreambuf_iter istrb_it05(istrs01);
   cistreambuf_iter istrb_it06(istrs01.rdbuf());
+
+#ifndef _GLIBCXX_DEBUG
   VERIFY( istrb_it05 == istrb_it06 );
+#endif
   
   // bool equal(istreambuf_iter& b)
   cistreambuf_iter istrb_it07(0);
@@ -57,12 +60,14 @@ void test02(void)
   cistreambuf_iter istrb_it10;
   VERIFY( istrb_it10.equal(istrb_it09) );
 
+#ifndef _GLIBCXX_DEBUG
   cistreambuf_iter istrb_it11(istrs01);
   cistreambuf_iter istrb_it12(istrs01.rdbuf());
   VERIFY( istrb_it11.equal(istrb_it12) );
   cistreambuf_iter istrb_it13(istrs01);
   cistreambuf_iter istrb_it14(istrs01.rdbuf());
   VERIFY( istrb_it14.equal(istrb_it13) );
+#endif
 
   cistreambuf_iter istrb_it15(istrs01);
   cistreambuf_iter istrb_it16;
@@ -77,9 +82,11 @@ void test02(void)
   cistreambuf_iter istrb_it20;
   VERIFY( istrb_it19 == istrb_it20 );
 
+#ifndef _GLIBCXX_DEBUG
   cistreambuf_iter istrb_it21(istrs01);
   cistreambuf_iter istrb_it22(istrs01.rdbuf());
   VERIFY( istrb_it22 == istrb_it21 );
+#endif
 
   cistreambuf_iter istrb_it23(istrs01);
   cistreambuf_iter istrb_it24;
diff --git a/libstdc++-v3/testsuite/24_iterators/istreambuf_iterator/debug/3_neg.cc b/libstdc++-v3/testsuite/24_iterators/istreambuf_iterator/debug/3_neg.cc
new file mode 100644
index 000..5e75704
--- /dev/null
+++ b/libstdc++-v3/testsuite/24_iterators/istreambuf_iterator/debug/3_neg.cc
@@ -0,0 +1,37 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more