az_python

@summary New and revised Python support.

This file provides autoconf support for those applications that want to embed python. It supports all pythons >= 2.2 which is the first official release containing distutils. Version 2.2 of python was released December 21, 2001. Since it actually executes the python, cross platform configuration will probably not work. Also, most of the platforms supported are consistent until you look into MacOSX. The python included with it is installed as a framework which is a very different environment to set up the normal tools such as gcc and libtool to deal with. Therefore, once we establish which python that we are going to use, we use its distutils to actually compile and link our modules or applications.

At this time, it does NOT support linking with Python statically. It does support dynamic linking.

This set of macros help define $PYTHON, $PYTHON_USE, $PYTHON_CSPEC and $PYTHON_LSPEC. $PYTHON defines the full executable path for the Python being linked to and is used within these macros to determine if that has been specified or found. These macros do execute this python version so it must be present on the system at configure time.

$PYTHON_USE is an automake variable that defines whether Python support should be included or not in your application. $PYTHON_CSPEC is a variable that supplies additional CFLAGS for the compilation of the application/shared library. $PYTHON_LSPEC is a variable that supplies additional LDFLAGS for linking the application/shared library.

The following is an example of how to set up for python usage within your application in your configure.in:

   AZ_PYTHON_DEFAULT( )
   AZ_PYTHON_ENABLE( )             # Optional
   AZ_PYTHON_WITH( )               # Optional
   AZ_PYTHON_PATH( )               # or AZ_PYTHON_INSIST( )
   # if $PYTHON is not defined, then the following do nothing.
   AZ_PYTHON_VERSION_ENSURE( [2.2] )
   AZ_PYTHON_CSPEC
   AZ_PYTHON_LSPEC

The AZ_PYTHON_DEFAULT sets the $PYTHON_USE to false. Thereby, excluding it if it was optional.

The AZ_PYTHON_ENABLE looks for the optional configure parameters of --enable-python/--disable-python and establishes the $PYTHON and $PYTHON_USE variables accordingly.

The AZ_PYTHON_WITH looks for the optional configure parameters of --with-python/--without-python and establishes the $PYTHON and $PYTHON_USE variables accordingly.

The AZ_PYTHON_PATH looks for python assuming that none has been previously found or defined and issues an error if it does not find it. If it does find it, it establishes the $PYTHON and $PYTHON_USE variables accordingly. AZ_PYTHON_INSIST could be used here instead if you want to insist that Python support be included using the --enable-python or --with-python checks previously done.

The AZ_PYTHON_VERSION_ENSURE issues an error if the Python previously found is not of version 2.2 or greater.

Once that these macros have be run, we can use PYTHON_USE within the makefile.am file to conditionally add the Python support such as:

Makefile.am example showing optional inclusion of directories:

  if PYTHON_USE
  plugins = plugins
  src = src
  else
  plugins =
  src =
  endif

  SUBDIRS = . $(plugins) $(src)

Makefile.am example showing optional shared library build:

  if PYTHON_USE
  lib_LTLIBRARIES        = libElemList.la
  libElemList_la_SOURCES = libElemList.c
  libElemList_la_CFLAGS  = @PYTHON_CSPEC@
  libElemList_la_LDFLAGS = @PYTHON_LSPEC@
  endif

Makefile.am example showing optional program build:

  if PYTHON_USE
  bin_PROGRAMS    = runFunc
  runFunc_SOURCES = runFunc.c
  runFunc_CFLAGS  = @PYTHON_CSPEC@
  runFunc_LDFLAGS = @PYTHON_LSPEC@
  endif

The above compiles the modules only if PYTHON_USE was specified as true. Also, the else portion of the if was optional.

# AZ_PYTHON_DEFAULT( )
# -----------------
# Sets the default to not include Python support.

AC_DEFUN([AZ_PYTHON_DEFAULT],
[
    az_python_use=false
    AM_CONDITIONAL(PYTHON_USE, test x"$az_python_use" = x"true")
])



# AZ_PYTHON_ENABLE( [path] )
# -----------------------------------------------------------------
# Handles the various --enable-python commands.
# Input:
#   $1 is the optional search path for the python executable if needed
# Ouput:
#   PYTHON_USE (AM_CONDITIONAL) is true if python executable found
#   and --enable-python was requested; otherwise false.
#   $PYTHON contains the full executable path to python if PYTHON_ENABLE_USE
#   is true.
#
# Example:
#   AZ_PYTHON_ENABLE( )
#   or
#   AZ_PYTHON_ENABLE( "/usr/bin" )

AC_DEFUN([AZ_PYTHON_ENABLE],
[
    AC_ARG_VAR([PYTHON],[Python Executable Path])

    # unless PYTHON was supplied to us (as a precious variable),
    # see if --enable-python[=PythonExecutablePath], --enable-python,
    # --disable-python or --enable-python=no was given.
    if test -z "$PYTHON"
    then
        AC_MSG_CHECKING(for --enable-python)
        AC_ARG_ENABLE(
            python,
            AC_HELP_STRING([--enable-python@<:@=PYTHON@:>@],
                [absolute path name of Python executable]
            ),
            [
                if test "$enableval" = "yes"
                then
                    # "yes" was specified, but we don't have a path
                    # for the executable.
                    # So, let's searth the PATH Environment Variable.
                    AC_MSG_RESULT(yes)
                    AC_PATH_PROG(
                        [PYTHON],
                        python,
                        [],
                        $1
                    )
                    if test -z "$PYTHON"
                    then
                        AC_MSG_ERROR(no path to python found)
                    fi
                    az_python_use=true
                    AM_CONDITIONAL(PYTHON_USE, test x"$az_python_use" = x"true")
                    AZ_PYTHON_PREFIX( )
                elif test "$enableval" = "no"
                then
                    AC_MSG_RESULT(no)
                    az_python_use=false
                    AM_CONDITIONAL(PYTHON_USE, test x"$az_python_use" = x"true")
                else
                    # $enableval must be the executable path then.
                    AC_SUBST([PYTHON], ["${enableval}"])
                    AC_MSG_RESULT($withval)
                    az_python_use=true
                    AM_CONDITIONAL(PYTHON_USE, test x"$az_python_use" = x"true")
                    AZ_PYTHON_PREFIX( )
                fi
            ],
            [
                # --with-python was not specified.
                AC_MSG_RESULT(no)
                az_python_use=false
                AM_CONDITIONAL(PYTHON_USE, test x"$az_python_use" = x"true")
            ]
        )
    fi

])



# AZ_PYTHON_CSPEC( )
# -----------------
# Set up the c compiler options to compile Python
# embedded programs/libraries in $PYTHON_CSPEC if
# $PYTHON has been defined.

AC_DEFUN([AZ_PYTHON_CSPEC],
[
    AC_ARG_VAR( [PYTHON], [Python Executable Path] )
    if test -n "$PYTHON"
    then
        az_python_prefix=`${PYTHON} -c "import sys; print sys.prefix"`
        if test -z "$az_python_prefix"
        then
            AC_MSG_ERROR([Python Prefix is not known])
        fi
        az_python_execprefix=`${PYTHON} -c "import sys; print sys.exec_prefix"`
        az_python_version=`$PYTHON -c "import sys; print sys.version[[:3]]"`
        az_python_includespec="-I${az_python_prefix}/include/python${az_python_version}"
        if test x"$python_prefix" != x"$python_execprefix"; then
            az_python_execspec="-I${az_python_execprefix}/include/python${az_python_version}"
            az_python_includespec="${az_python_includespec} $az_python_execspec"
        fi
        az_python_ccshared=`${PYTHON} -c "import distutils.sysconfig; print distutils.sysconfig.get_config_var('CFLAGSFORSHARED')"`
        az_python_cspec="${az_python_ccshared} ${az_python_includespec}"
        AC_SUBST([PYTHON_CSPEC], [${az_python_cspec}])
        AC_MSG_NOTICE([PYTHON_CSPEC=${az_python_cspec}])
    fi
])



# AZ_PYTHON_INSIST( )
# -----------------
# Look for Python and set the output variable 'PYTHON'
# to 'python' if found, empty otherwise.

AC_DEFUN([AZ_PYTHON_PATH],
[
    AC_ARG_VAR( [PYTHON], [Python Executable Path] )
    if test -z "$PYTHON"
    then
        AC_MSG_ERROR([Python Executable not found])
    fi
])



# AZ_PYTHON_LSPEC( )
# -----------------
# Set up the linker options to link Python embedded
# programs/libraries in $PYTHON_LSPEC if $PYTHON
# has been defined.

AC_DEFUN([AZ_PYTHON_LSPEC],
[
    AC_ARG_VAR( [PYTHON], [Python Executable Path] )
    if test -n "$PYTHON"
    then
        AZ_PYTHON_RUN([
import sys
import distutils.sysconfig
strUseFrameWork = "--enable-framework"
dictConfig = distutils.sysconfig.get_config_vars( )
strConfigArgs = dictConfig.get("CONFIG_ARGS")
strLinkSpec =  dictConfig.get('LDFLAGS')
if -1 ==  strConfigArgs.find(strUseFrameWork):
    strLibPL = dictConfig.get("LIBPL")
    if strLibPL and (strLibPL != ""):
        strLinkSpec += " -L%s" % (strLibPL)
    strSys = dictConfig.get("SYSLIBS")
    if strSys and (strSys != ""):
        strLinkSpec += " %s" % (strSys)
    strSHL = dictConfig.get("SHLIBS")
    if strSHL and (strSHL != ""):
        strLinkSpec += " %s" % (strSHL)
    # Construct the Python Library Name.
    strTmplte = " -lpython%d.%d"
    if (sys.platform == "win32") or (sys.platform == "os2emx"):
        strTmplte = " -lpython%d%d"
    strWrk = strTmplte % ( (sys.hexversion >> 24),
                            ((sys.hexversion >> 16) & 0xff))
    strLinkSpec += strWrk
else:
    # This is not ideal since it changes the search path
    # for Frameworks which could have side-effects on
    # other included Frameworks.  However, it is necessary
    # where someone has installed more than one frameworked
    # Python.  Frameworks are really only used in MacOSX.
    strLibFW = dictConfig.get("PYTHONFRAMEWORKPREFIX")
    if strLibFW and (strLibFW != ""):
        strLinkSpec += " -F%s" % (strLibFW)
strLinkSpec += " %s" % (dictConfig.get('LINKFORSHARED'))
print strLinkSpec
        ])
        AC_SUBST([PYTHON_LSPEC], [${az_python_output}])
        AC_MSG_NOTICE([PYTHON_LSPEC=${az_python_output}])
    fi
])



# AZ_PYTHON_PATH( )
# -----------------
# Look for Python and set the output variable 'PYTHON'
# to 'python' if found, empty otherwise.

AC_DEFUN([AZ_PYTHON_PATH],
[
    AC_ARG_VAR( [PYTHON], [Python Executable Path] )
    AC_PATH_PROG( PYTHON, python, [], $1 )
    if test -z "$PYTHON"
    then
        AC_MSG_ERROR([Python Executable not found])
    else
        az_python_use=true
    fi
    AM_CONDITIONAL(PYTHON_USE, test "$az_python_use" = "true")
])



# AZ_PYTHON_PREFIX( )
# -------------------
# Use the values of $prefix and $exec_prefix for the corresponding
# values of PYTHON_PREFIX and PYTHON_EXEC_PREFIX.

AC_DEFUN([AZ_PYTHON_PREFIX],
[
    if test -z "$PYTHON"
    then
        AC_MSG_ERROR([Python Executable Path is not known])
    fi
    ax_python_prefix=`${PYTHON} -c "import sys; print sys.prefix"`
    ax_python_execprefix=`${PYTHON} -c "import sys; print sys.exec_prefix"`
    AC_SUBST([PYTHON_PREFIX], ["${ax_python_prefix}"])
    AC_SUBST([PYTHON_EXECPREFIX], ["${ax_python_execprefix}"])
])



# AZ_PYTHON_RUN( PYTHON_PROGRAM )
# -----------------
# Run a Python Test Program saving its output
# in az_python_output and its condition code
# in az_python_cc.

AC_DEFUN([AZ_PYTHON_RUN],
[
    AC_ARG_VAR( [PYTHON], [Python Executable Path] )
    if test -z "$PYTHON"
    then
        AC_MSG_ERROR([Python Executable not found])
    else
        cat >conftest.py <<_ACEOF
$1
_ACEOF
        az_python_output=`$PYTHON conftest.py`
        az_python_cc=$?
        rm conftest.py
        if test -f "conftest.pyc"
        then
            rm conftest.pyc
        fi
    fi
])



# AZ_PYTHON_VERSION_CHECK( VERSION, [ACTION-IF-TRUE], [ACTION-IF-FALSE] )
# -----------------------------------------------------------------------------
# Run ACTION-IF-TRUE if the Python interpreter has version >= VERSION.
# Run ACTION-IF-FALSE otherwise.
# This test uses sys.hexversion instead of the string equivalant (first
# word of sys.version), in order to cope with versions such as 2.2c1.
# hexversion has been introduced in Python 1.5.2; it's probably not
# worth to support older versions (1.5.1 was released on October 31, 1998).

AC_DEFUN([AZ_PYTHON_VERSION_CHECK],
 [
    AC_ARG_VAR( [PYTHON], [Python Executable Path] )
    if test -n "$PYTHON"
    then
        AC_MSG_CHECKING([whether $PYTHON version >= $1])
        AZ_PYTHON_RUN([
import sys, string
# split strings by '.' and convert to numeric.  Append some zeros
# because we need at least 4 digits for the hex conversion.
minver = map(int, string.split('$1', '.')) + [[0, 0, 0]]
minverhex = 0
for i in xrange(0, 4): minverhex = (minverhex << 8) + minver[[i]]
if sys.hexversion >= minverhex:
    sys.exit( 0 )
else:
    sys.exit( 1 )
        ])
        if test $az_python_cc -eq 0
        then
            $2
        m4_ifvaln(
            [$3],
            [else $3]
        )
        fi
    fi
])



# AZ_PYTHON_VERSION_ENSURE( VERSION )
# -----------------
# Insure that the Python Interpreter Version
# is greater than or equal to the VERSION
# parameter.

AC_DEFUN([AZ_PYTHON_VERSION_ENSURE],
[
    AZ_PYTHON_VERSION_CHECK(
        [$1],
        [AC_MSG_RESULT(yes)],
        [AC_MSG_ERROR(too old)]
    )
])



# AZ_PYTHON_WITH( [path] )
# -----------------------------------------------------------------
# Handles the various --with-python commands.
# Input:
#   $1 is the optional search path for the python executable if needed
# Ouput:
#   PYTHON_USE (AM_CONDITIONAL) is true if python executable found
#   and --with-python was requested; otherwise false.
#   $PYTHON contains the full executable path to python if PYTHON_USE
#   is true.
#
# Example:
#   AZ_PYTHON_WITH( )
#   or
#   AZ_PYTHON_WITH("/usr/bin")

AC_DEFUN([AZ_PYTHON_WITH],
[
    AC_ARG_VAR([PYTHON],[Python Executable Path])

    # unless PYTHON was supplied to us (as a precious variable),
    # see if --with-python[=PythonExecutablePath], --with-python,
    # --without-python or --with-python=no was given.
    if test -z "$PYTHON"
    then
        AC_MSG_CHECKING(for --with-python)
        AC_ARG_WITH(
            python,
            AC_HELP_STRING([--with-python@<:@=PYTHON@:>@],
                [absolute path name of Python executable]
            ),
            [
                if test "$withval" = "yes"
                then
                    # "yes" was specified, but we don't have a path
                    # for the executable.
                    # So, let's searth the PATH Environment Variable.
                    AC_MSG_RESULT(yes)
                    AC_PATH_PROG(
                        [PYTHON],
                        python,
                        [],
                        $1
                    )
                    if test -z "$PYTHON"
                    then
                        AC_MSG_ERROR(no path to python found)
                    fi
                    az_python_use=true
                    AM_CONDITIONAL(PYTHON_USE, test x"$az_python_use" = x"true")
                    AZ_PYTHON_PREFIX( )
                elif test "$withval" = "no"
                then
                    AC_MSG_RESULT(no)
                    az_python_use=false
                    AM_CONDITIONAL(PYTHON_USE, test x"$az_python_use" = x"true")
                else
                    # $withval must be the executable path then.
                    AC_SUBST([PYTHON], ["${withval}"])
                    AC_MSG_RESULT($withval)
                    az_python_use=true
                    AM_CONDITIONAL(PYTHON_USE, test x"$az_python_use" = x"true")
                    AZ_PYTHON_PREFIX( )
                fi
            ],
            [
                # --with-python was not specified.
                AC_MSG_RESULT(no)
                az_python_use=false
                AM_CONDITIONAL(PYTHON_USE, test x"$az_python_use" = x"true")
            ]
        )
    fi

])