[tor-commits] [stegotorus/master] Add autoconf probes for C++11 and method deletion; use the latter in crypt.h.
zwol at torproject.org
zwol at torproject.org
Fri Jul 20 23:17:07 UTC 2012
commit 623c1912051d4fccec3be22e98e53d9f680f6f8a
Author: Zack Weinberg <zackw at panix.com>
Date: Mon Mar 5 16:49:13 2012 -0800
Add autoconf probes for C++11 and method deletion; use the latter in crypt.h.
---
configure.ac | 3 +
m4/cxx_delete_method.m4 | 76 ++++++++++++++++++++++++++++++++
m4/cxxflags_stdcxx_11.m4 | 107 ++++++++++++++++++++++++++++++++++++++++++++++
m4/winsock.m4 | 10 ++--
src/crypt.h | 12 +++---
5 files changed, 197 insertions(+), 11 deletions(-)
diff --git a/configure.ac b/configure.ac
index ca76a7a..d491479 100644
--- a/configure.ac
+++ b/configure.ac
@@ -65,6 +65,9 @@ LIBS="$LIBS $ws32_LIBS"
AC_CHECK_HEADERS([execinfo.h],,, [AC_INCLUDES_DEFAULT()])
+AX_CXXFLAGS_STDCXX_11([ext])
+AX_CXX_DELETE_METHOD
+
### Output ###
AC_CONFIG_FILES([Makefile])
diff --git a/m4/cxx_delete_method.m4 b/m4/cxx_delete_method.m4
new file mode 100644
index 0000000..2f7decf
--- /dev/null
+++ b/m4/cxx_delete_method.m4
@@ -0,0 +1,76 @@
+# ============================================================================
+# http://www.gnu.org/software/autoconf-archive/ax_cxx_delete_method.m4
+# ============================================================================
+#
+# SYNOPSIS
+#
+# AX_CXX_DELETE_METHOD
+#
+# DESCRIPTION
+#
+# Check whether the C++11 '= delete' syntax, for suppressing undesired
+# implicit methods, is supported. If it is, the macro DELETE_METHOD is
+# defined to '= delete'; otherwise it is defined to nothing. Thus, you
+# can write
+#
+# class foo {
+# ...
+# private:
+# foo(foo const&) DELETE_METHOD;
+# };
+#
+# to delete the 'foo' copy constructor or fall back to the idiom of
+# a private undefined method if the compiler doesn't support this.
+#
+# Does not test '= delete' on a template specialization.
+# Does not ensure that the compiler is in C++11 mode.
+#
+# LICENSE
+#
+# Copyright (c) 2012 Zack Weinberg <zackw at panix.com>
+#
+# Copying and distribution of this file, with or without modification, are
+# permitted in any medium without royalty provided the copyright notice
+# and this notice are preserved. This file is offered as-is, without any
+# warranty.
+
+AC_DEFUN([AX_CXX_DELETE_METHOD], [dnl
+ AC_LANG_ASSERT([C++])
+ # This compilation should succeed...
+ AC_CACHE_CHECK(whether $CXX accepts method deletion,
+ ax_cv_cxx_delete_method_syntax, [
+ AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+ struct foo {
+ foo(double);
+ foo(int) = delete;
+ };
+ extern void t(foo const&);
+ void tt(double n) { t(n); }
+ ]])],
+ [ax_cv_cxx_delete_method_syntax=yes],
+ [ax_cv_cxx_delete_method_syntax=no])])
+ # ... and this one should fail.
+ AC_CACHE_CHECK(whether $CXX enforces method deletion,
+ ax_cv_cxx_delete_method_enforced, [
+ AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+ struct foo {
+ foo(double);
+ foo(int) = delete;
+ };
+ extern void t(foo const&);
+ void tt(int n) { t(n); }
+ ]])],
+ [ax_cv_cxx_delete_method_enforced=no],
+ [ax_cv_cxx_delete_method_enforced=yes])])
+ if test $ax_cv_cxx_delete_method_syntax = yes &&
+ test $ax_cv_cxx_delete_method_enforced = yes
+ then
+ AC_DEFINE([DELETE_METHOD], [= delete],
+ [Define as `= delete' if your compiler supports C++11 method
+ deletion, as nothing otherwise.])
+ else
+ AC_DEFINE([DELETE_METHOD], [],
+ [Define as `= delete' if your compiler supports C++11 method
+ deletion, as nothing otherwise.])
+ fi
+])
diff --git a/m4/cxxflags_stdcxx_11.m4 b/m4/cxxflags_stdcxx_11.m4
new file mode 100644
index 0000000..1c5c0f2
--- /dev/null
+++ b/m4/cxxflags_stdcxx_11.m4
@@ -0,0 +1,107 @@
+# ============================================================================
+# http://www.gnu.org/software/autoconf-archive/ax_cxxflags_stdcxx_11.html
+# ============================================================================
+#
+# SYNOPSIS
+#
+# AX_CXXFLAGS_STDCXX_11([ext|noext])
+#
+# DESCRIPTION
+#
+# Check for baseline language coverage in the compiler for the C++11
+# standard; if necessary, add switches to CXXFLAGS to enable support.
+# Errors out if no mode that supports C++11 baseline syntax can be found.
+# The argument, if specified, indicates whether you insist on an extended
+# mode (e.g. -std=gnu++11) or a strict conformance mode (e.g. -std=c++11).
+# If neither is specified, you get whatever works, with preference for an
+# extended mode.
+#
+# LICENSE
+#
+# Copyright (c) 2008 Benjamin Kosnik <bkoz at redhat.com>
+# Copyright (c) 2012 Zack Weinberg <zackw at panix.com>
+#
+# Copying and distribution of this file, with or without modification, are
+# permitted in any medium without royalty provided the copyright notice
+# and this notice are preserved. This file is offered as-is, without any
+# warranty.
+
+#serial 8
+
+m4_define([_AX_CXXFLAGS_STDCXX_11_testbody], [
+ template <typename T>
+ struct check
+ {
+ static_assert(sizeof(int) <= sizeof(T), "not big enough");
+ };
+
+ typedef check<check<bool>> right_angle_brackets;
+
+ int a;
+ decltype(a) b;
+
+ typedef check<int> check_type;
+ check_type c;
+ check_type&& cr = static_cast<check_type&&>(c);
+])
+
+AC_DEFUN([AX_CXXFLAGS_STDCXX_11], [dnl
+ m4_if([$1], [], [],
+ [$1], [ext], [],
+ [$1], [noext], [],
+ [m4_fatal([invalid argument `$1' to AX_CXXFLAGS_STDCXX_11])])dnl
+ AC_LANG_ASSERT([C++])dnl
+ ac_success=no
+ AC_CACHE_CHECK(whether $CXX supports C++11 features by default,
+ ax_cv_cxx_compile_cxx11,
+ [AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXXFLAGS_STDCXX_11_testbody])],
+ [ax_cv_cxx_compile_cxx11=yes],
+ [ax_cv_cxx_compile_cxx11=no])])
+ if test x$ax_cv_cxx_compile_cxx11 = xyes; then
+ ac_success=yes
+ fi
+
+ m4_if([$1], [noext], [], [dnl
+ if test x$ac_success = xno; then
+ for switch in -std=gnu++11 -std=gnu++0x; do
+ cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch])
+ AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch,
+ $cachevar,
+ [ac_save_CXXFLAGS="$CXXFLAGS"
+ CXXFLAGS="$CXXFLAGS $switch"
+ AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXXFLAGS_STDCXX_11_testbody])],
+ [eval $cachevar=yes],
+ [eval $cachevar=no])
+ CXXFLAGS="$ac_save_CXXFLAGS"])
+ if eval test x\$$cachevar = xyes; then
+ CXXFLAGS="$CXXFLAGS $switch"
+ ac_success=yes
+ break
+ fi
+ done
+ fi])
+
+ m4_if([$1], [ext], [], [dnl
+ if test x$ac_success = xno; then
+ for switch in -std=c++11 -std=c++0x; do
+ cachevar=AS_TR_SH([ax_cv_cxx_compile_cxx11_$switch])
+ AC_CACHE_CHECK(whether $CXX supports C++11 features with $switch,
+ $cachevar,
+ [ac_save_CXXFLAGS="$CXXFLAGS"
+ CXXFLAGS="$CXXFLAGS $switch"
+ AC_COMPILE_IFELSE([AC_LANG_SOURCE([_AX_CXXFLAGS_STDCXX_11_testbody])],
+ [eval $cachevar=yes],
+ [eval $cachevar=no])
+ CXXFLAGS="$ac_save_CXXFLAGS"])
+ if eval test x\$$cachevar = xyes; then
+ CXXFLAGS="$CXXFLAGS $switch"
+ ac_success=yes
+ break
+ fi
+ done
+ fi])
+
+ if test x$ac_success = xno; then
+ AC_MSG_ERROR([*** A compiler with support for C++11 language features is required.])
+ fi
+])
diff --git a/m4/winsock.m4 b/m4/winsock.m4
index a90cc50..fd3d8b5 100644
--- a/m4/winsock.m4
+++ b/m4/winsock.m4
@@ -47,10 +47,10 @@ AC_DEFUN([AX_LIB_WINSOCK2],
])
ws32_LIBS=
- if test "x$ac_cv_search_ntohl" == "xno"; then
- AC_MSG_ERROR([could not find ntohl])
- elif test "x$ac_cv_search_ntohl" != "xnone required"; then
- ws32_LIBS="$ac_cv_search_ntohl"
- fi
+ case "$ac_cv_search_ntohl" in
+ no) AC_MSG_ERROR([could not find ntohl]) ;;
+ "none required") ;;
+ *) ws32_LIBS="$ac_cv_search_ntohl"
+ esac
AC_SUBST(ws32_LIBS)
])
diff --git a/src/crypt.h b/src/crypt.h
index 062625e..e87de0a 100644
--- a/src/crypt.h
+++ b/src/crypt.h
@@ -25,8 +25,8 @@ struct encryptor
encryptor() {}
private:
- encryptor(const encryptor&);
- encryptor& operator=(const encryptor&);
+ encryptor(const encryptor&) DELETE_METHOD;
+ encryptor& operator=(const encryptor&) DELETE_METHOD;
};
struct decryptor
@@ -55,8 +55,8 @@ struct decryptor
decryptor() {}
private:
- decryptor(const decryptor&);
- decryptor& operator=(const decryptor&);
+ decryptor(const decryptor&) DELETE_METHOD;
+ decryptor& operator=(const decryptor&) DELETE_METHOD;
};
/** Generate keying material from an initial key of some kind, a salt
@@ -95,8 +95,8 @@ struct key_generator
virtual ~key_generator();
key_generator() {}
private:
- key_generator(const decryptor&);
- key_generator& operator=(const decryptor&);
+ key_generator(const key_generator&) DELETE_METHOD;
+ key_generator& operator=(const key_generator&) DELETE_METHOD;
};
#endif
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