Add a new compiler object method: has_members (#723)

* Add a new compiler object method: has_members

Identical to 'cc.has_member', except that this takes multiple members
and all of them must exist else it returns false.

This is useful when you want to verify that a structure has all of
a given set of fields. Individually checking each member is horrifying.

* Fix typo in exceptions for has_member(s)

1 files changed, 12 insertions, 7 deletions

diff --git a/mesonbuild/compilers.py b/mesonbuild/compilers.py
index 58444bb..1c6c1da 100644
--- a/mesonbuild/compilers.py
+++ b/mesonbuild/compilers.py
@@ -902,16 +902,21 @@ int main(int argc, char **argv) {
         # directly try to link via main().
         return self.links('int main() {{ {0}; }}'.format('__builtin_' + funcname), env, args)
 
-    def has_member(self, typename, membername, prefix, env, extra_args=None):
+    def has_members(self, typename, membernames, prefix, env, extra_args=None):
         if extra_args is None:
             extra_args = []
-        templ = '''%s
-void bar() {
-    %s foo;
-    foo.%s;
-};
+        templ = '''{0}
+void bar() {{
+    {1} {2};
+    {3}
+}};
 '''
-        return self.compiles(templ % (prefix, typename, membername), env, extra_args)
+        # Create code that accesses all members
+        members = ''
+        for m in membernames:
+            members += 'foo.{};\n'.format(m)
+        code = templ.format(prefix, typename, 'foo', members)
+        return self.compiles(code, env, extra_args)
 
     def has_type(self, typename, prefix, env, extra_args):
         templ = '''%s