qapi: Record 'include' directives in parse tree

The parse tree is a list of expressions.  Except include expressions
currently get replaced by the included file's parse tree.

Instead of throwing away the include expression, keep it with the file
name expanded so you don't have to track the including file's
directory to make sense of it.

A future commit will put this include expression to use.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180211093607.27351-16-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: fix check of expr after assignment]
Signed-off-by: Eric Blake <eblake@redhat.com>

scripts/qapi/common.py

@@ -290,8 +290,11 @@ def __init__(self, fp, previously_included=[], incl_info=None):
                 if not isinstance(include, str):
                     raise QAPISemError(info,
                                        "Value of 'include' must be a string")
-                exprs_include = self._include(include, info,
-                                              os.path.dirname(self.fname),
+                incl_fname = os.path.join(os.path.dirname(self.fname),
+                                          include)
+                self.exprs.append({'expr': {'include': incl_fname},
+                                   'info': info})
+                exprs_include = self._include(include, info, incl_fname,
                                               previously_included)
                 if exprs_include:
                     self.exprs.extend(exprs_include.exprs)
@@ -326,8 +329,7 @@ def reject_expr_doc(doc):
                 "Documentation for '%s' is not followed by the definition"
                 % doc.symbol)
 
-    def _include(self, include, info, base_dir, previously_included):
-        incl_fname = os.path.join(base_dir, include)
+    def _include(self, include, info, incl_fname, previously_included):
         incl_abs_fname = os.path.abspath(incl_fname)
         # catch inclusion cycle
         inf = info
@@ -893,6 +895,9 @@ def check_exprs(exprs):
         info = expr_elem['info']
         doc = expr_elem.get('doc')
 
+        if 'include' in expr:
+            continue
+
         if not doc and doc_required:
             raise QAPISemError(info,
                                "Expression missing documentation comment")
@@ -932,6 +937,9 @@ def check_exprs(exprs):
     # Try again for hidden UnionKind enum
     for expr_elem in exprs:
         expr = expr_elem['expr']
+
+        if 'include' in expr:
+            continue
         if 'union' in expr and not discriminator_find_enum_define(expr):
             name = '%sKind' % expr['union']
         elif 'alternate' in expr:
@@ -947,6 +955,8 @@ def check_exprs(exprs):
         info = expr_elem['info']
         doc = expr_elem.get('doc')
 
+        if 'include' in expr:
+            continue
         if 'enum' in expr:
             check_enum(expr, info)
         elif 'union' in expr:
@@ -1667,6 +1677,8 @@ def _def_exprs(self, exprs):
                 self._def_command(expr, info, doc)
             elif 'event' in expr:
                 self._def_event(expr, info, doc)
+            elif 'include' in expr:
+                pass
             else:
                 assert False