google_namespace.m4 revision bdd62c531bbdea115a3a7e71bba91c19dd319cc4 
1# Allow users to override the namespace we define our application's classes in
2# Arg $1 is the default namespace to use if --enable-namespace isn't present.
3
4# In general, $1 should be 'google', so we put all our exported symbols in a
5# unique namespace that is not likely to conflict with anyone else.  However,
6# when it makes sense -- for instance, when publishing stl-like code -- you
7# may want to go with a different default, like 'std'.
8
9# We guarantee the invariant that GOOGLE_NAMESPACE starts with ::,
10# unless it's the empty string.  Thus, it's always safe to do
11# GOOGLE_NAMESPACE::foo and be sure you're getting the foo that's
12# actually in the google namespace, and not some other namespace that
13# the namespace rules might kick in.
14
15AC_DEFUN([AC_DEFINE_GOOGLE_NAMESPACE],
16  [google_namespace_default=[$1]
17   AC_ARG_ENABLE(namespace, [  --enable-namespace=FOO to define these Google
18                             classes in the FOO namespace. --disable-namespace
19                             to define them in the global namespace. Default
20                             is to define them in namespace $1.],
21                 [case "$enableval" in
22                    yes) google_namespace="$google_namespace_default" ;;
23                     no) google_namespace="" ;;
24                      *) google_namespace="$enableval" ;;
25                  esac],
26                 [google_namespace="$google_namespace_default"])
27   if test -n "$google_namespace"; then
28     ac_google_namespace="::$google_namespace"
29     ac_google_start_namespace="namespace $google_namespace {"
30     ac_google_end_namespace="}"
31   else
32     ac_google_namespace=""
33     ac_google_start_namespace=""
34     ac_google_end_namespace=""
35   fi
36   AC_DEFINE_UNQUOTED(GOOGLE_NAMESPACE, $ac_google_namespace,
37                      Namespace for Google classes)
38   AC_DEFINE_UNQUOTED(_START_GOOGLE_NAMESPACE_, $ac_google_start_namespace,
39                      Puts following code inside the Google namespace)
40   AC_DEFINE_UNQUOTED(_END_GOOGLE_NAMESPACE_,  $ac_google_end_namespace,
41                      Stops putting the code inside the Google namespace)
42])
43