From 8fb7d02686ed85ad799dfd902ea88d977dab1868 Mon Sep 17 00:00:00 2001
From: Russell Bryant <russell@ovn.org>
Date: Thu, 17 Dec 2015 19:58:33 -0500
Subject: [PATCH] configure: Check for presence of Python 3.

The configure script already checked for Python 2 (>=2.7).  Add another
check for Python 3 (>=3.4).  This will be used later for automatically
running tests with Python 3 as well if available.

Signed-off-by: Russell Bryant <russell@ovn.org>
Acked-by: Ben Pfaff <blp@ovn.org>
---
 configure.ac      |  1 +
 m4/openvswitch.m4 | 42 ++++++++++++++++++++++++++++++++++++++++++
 tests/atlocal.in  |  5 +++++
 3 files changed, 48 insertions(+)

diff --git a/configure.ac b/configure.ac
index 49aa182d4..05d80d5dd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -95,6 +95,7 @@ OVS_CHECK_OPENSSL
 OVS_CHECK_LIBCAPNG
 OVS_CHECK_LOGDIR
 OVS_CHECK_PYTHON
+OVS_CHECK_PYTHON3
 OVS_CHECK_FLAKE8
 OVS_CHECK_DOT
 OVS_CHECK_IF_PACKET
diff --git a/m4/openvswitch.m4 b/m4/openvswitch.m4
index 0149c3078..fa85d3f30 100644
--- a/m4/openvswitch.m4
+++ b/m4/openvswitch.m4
@@ -358,6 +358,48 @@ else:
    fi
    AM_CONDITIONAL([HAVE_PYTHON], [test "$HAVE_PYTHON" = yes])])
 
+dnl Checks for Python 3.x, x >= 4.
+AC_DEFUN([OVS_CHECK_PYTHON3],
+  [AC_CACHE_CHECK(
+     [for Python 3.x for x >= 4],
+     [ovs_cv_python3],
+     [if test -n "$PYTHON3"; then
+        ovs_cv_python3=$PYTHON3
+      else
+        ovs_cv_python3=no
+        for binary in python3 python3.4; do
+          ovs_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+          for dir in $PATH; do
+            IFS=$ovs_save_IFS
+            test -z "$dir" && dir=.
+            if test -x "$dir"/"$binary" && "$dir"/"$binary" -c 'import sys
+if sys.hexversion >= 0x03040000 and sys.hexversion < 0x04000000:
+    sys.exit(0)
+else:
+    sys.exit(1)'; then
+              ovs_cv_python3=$dir/$binary
+              break 2
+            fi
+          done
+        done
+        if test $ovs_cv_python != no; then
+          if test -x "$ovs_cv_python" && ! "$ovs_cv_python" -c 'import six' >/dev/null 2>&1; then
+            ovs_cv_python=no
+            AC_MSG_WARN([Missing Python six library.])
+          fi
+        fi
+      fi])
+   AC_SUBST([HAVE_PYTHON3])
+   AM_MISSING_PROG([PYTHON3], [python3])
+   if test $ovs_cv_python3 != no; then
+     PYTHON3=$ovs_cv_python3
+     HAVE_PYTHON3=yes
+   else
+     HAVE_PYTHON3=no
+   fi
+   AM_CONDITIONAL([HAVE_PYTHON3], [test "$HAVE_PYTHON3" = yes])])
+
+
 dnl Checks for dot.
 AC_DEFUN([OVS_CHECK_FLAKE8],
   [AC_CACHE_CHECK(
diff --git a/tests/atlocal.in b/tests/atlocal.in
index 2a163dbb8..f174061d8 100644
--- a/tests/atlocal.in
+++ b/tests/atlocal.in
@@ -1,6 +1,7 @@
 # -*- shell-script -*-
 HAVE_OPENSSL='@HAVE_OPENSSL@'
 HAVE_PYTHON='@HAVE_PYTHON@'
+HAVE_PYTHON3='@HAVE_PYTHON3@'
 EGREP='@EGREP@'
 PERL='@PERL@'
 
@@ -8,6 +9,10 @@ if test x"$PYTHON" = x; then
     PYTHON='@PYTHON@'
 fi
 
+if test x"$PYTHON3" = x; then
+    PYTHON3='@PYTHON3@'
+fi
+
 PYTHONPATH=$abs_top_srcdir/python:$abs_top_builddir/tests:$PYTHONPATH
 export PYTHONPATH
 
-- 
2.20.1