dnl
dnl find_apr.m4 : locate the APR include files and libraries
dnl
dnl This macro file can be used by applications to find and use the APR
dnl library. It provides a standardized mechanism for using APR. It supports
dnl embedding APR into the application source, or locating an installed
dnl copy of APR.
dnl
dnl APR_FIND_APR([srcdir])
dnl
dnl   where srcdir is the location of the bundled APR source directory, or
dnl   empty if source is not bundled.
dnl
dnl
dnl Sets the following variables on exit:
dnl
dnl   apr_libdir : A custom directory to use for linking (the -L switch).
dnl                If APR exists in a standard location, this variable
dnl                will be empty
dnl
dnl   apr_la_file : If a libtool .la file exists, this will refer to it. If
dnl                 there is no .la file, then this variable will be empty.
dnl
dnl   apr_includes : Where the APR includes are located, if a non-standard
dnl                  location. This variable has the format "-Idir -Idir".
dnl                  It may specify more than one directory.
dnl
dnl   apr_srcdir : If an APR source tree is available and needs to be
dnl                (re)configured, this refers to it.
dnl
dnl   apr_config : If the apr-config tool exists, this refers to it.
dnl
dnl   apr_vars : If the APR config file (APRVARS) exists, this refers to it.
dnl
dnl   apr_found : "yes", "no", "reconfig"
dnl
dnl Note: At this time, we cannot find *both* a source dir and a build dir.
dnl       If both are available, the build directory should be passed to
dnl       the --with-apr switch (apr_srcdir will be empty).
dnl
dnl Note: the installation layout is presumed to follow the standard
dnl       PREFIX/lib and PREFIX/include pattern. If the APR config file
dnl       is available (and can be found), then non-standard layouts are
dnl       possible, since it will be described in the config file.
dnl
dnl If apr_found is "yes" or "reconfig", then the caller should link using
dnl apr_la_file, if available; otherwise, -lapr should be used (and if
dnl apr_libdir is not null, then -L$apr_libdir). If apr_includes is not null,
dnl then it should be used during compilation.
dnl
dnl If a source directory is available and needs to be (re)configured, then
dnl apr_srcdir specifies the directory and apr_found is "reconfig".
dnl

AC_DEFUN(APR_FIND_APR, [
  apr_found="no"

  preserve_LIBS="$LIBS"
  preserve_LDFLAGS="$LDFLAGS"
  preserve_CFLAGS="$CFLAGS"

  AC_MSG_CHECKING(for APR)
  AC_ARG_WITH(apr,
  [  --with-apr=DIR          prefix for installed APR, or path to APR build tree],
  [
    if test "$withval" = "no" || test "$withval" = "yes"; then
      AC_MSG_ERROR([--with-apr requires a directory to be provided])
    fi

    if test -x "$withval/bin/apr-config"; then
       apr_config="$withval/bin/apr-config"
       CFLAGS="$CFLAGS `$withval/bin/apr-config --cflags`"
       LIBS="$LIBS `$withval/bin/apr-config --libs`"
       LDFLAGS="$LDFLAGS `$withval/bin/apr-config --ldflags`"
    else
       apr_config=""
    fi

    LIBS="$LIBS -lapr"
    LDFLAGS="$preserve_LDFLAGS -L$withval/lib"
    AC_TRY_LINK_FUNC(apr_initialize, [
      if test -f "$withval/include/apr.h"; then
        dnl found an installed version of APR
        apr_found="yes"
        apr_libdir="$withval/lib"
        apr_includes="-I$withval/include"
      fi
    ], [
      dnl look for a build tree (note: already configured/built)
      if test -f "$withval/libapr.la"; then
        apr_found="yes"
        apr_libdir=""
        apr_la_file="$withval/libapr.la"
        apr_vars="$withval/APRVARS"
        if test -x $withval/apr-config; then
          apr_config="$withval/apr-config"
        else
          apr_config=""
        fi
        apr_includes="-I$withval/include"
        if test ! -f "$withval/APRVARS.in"; then
          dnl extract the APR source directory without polluting our
          dnl shell variable space
          apr_srcdir="`sed -n '/APR_SOURCE_DIR/s/.*"\(.*\)"/\1/p' $apr_vars`"
          apr_includes="$apr_includes -I$apr_srcdir/include"
        fi
      fi
    ])

    dnl if --with-apr is used, then the target prefix/directory must be valid
    if test "$apr_found" != "yes"; then
      AC_MSG_ERROR([
The directory given to --with-apr does not specify a prefix for an installed
APR, nor an APR build directory.])
    fi
  ],[
    dnl always look in the builtin/default places
    LIBS="$LIBS -lapr"
    AC_TRY_LINK_FUNC(apr_initialize, [
        dnl We don't have to do anything.
        apr_found="yes"
        apr_srcdir=""
        apr_libdir=""
        apr_includes=""
        apr_la_file=""
        apr_config=""
        apr_vars=""
      ], [
      dnl look in the some standard places (apparently not in builtin/default)
      for lookdir in /usr /usr/local /opt/apr ; do
        if test "$apr_found" != "yes"; then
          LDFLAGS="$preserve_LDFLAGS -L$lookdir/lib"
          AC_TRY_LINK_FUNC(apr_initialize, [
            apr_found="yes"
            apr_libdir="$lookdir/lib" 
            apr_includes="-I$lookdir/include"
            if test -x "$withval/bin/apr-config"; then
              apr_config="$withval/bin/apr-config"
            else
              apr_config=""
            fi
          ])
        fi
      done
    ])
    dnl We attempt to guess what the data will be *after* configure is run.
    dnl Note, if we don't see configure, but do have configure.in, it'd be
    dnl nice to run buildconf, but that's for another day.
    if test "$apr_found" = "no" && test -n "$1" && test -x "$1/configure"; then
      apr_found="reconfig"
      apr_srcdir="$1"
      apr_libdir=""
      apr_la_file="$apr_srcdir/libapr.la"
      apr_vars="$apr_srcdir/APRVARS"
      if test -f "$apr_srcdir/apr-config.in"; then
        apr_config="$apr_srcdir/apr-config"
      else
        apr_config=""
      fi
      apr_includes="-I$apr_srcdir/include"
    fi
  ])

  if test "$apr_found" != "no" && test "$apr_libdir" != ""; then
    if test "$apr_vars" = "" && test -f "$apr_libdir/APRVARS"; then
      apr_vars="$apr_libdir/APRVARS"
    fi
    if test "$apr_la_file" = "" && test -f "$apr_libdir/libapr.la"; then
      apr_la_file="$apr_libdir/libapr.la"
    fi
  fi

  AC_MSG_RESULT($apr_found)
  CFLAGS="$preserve_CFLAGS"
  LIBS="$preserve_LIBS"
  LDFLAGS="$preserve_LDFLAGS"
])