[PATCH v2 3/4] tools/widl: Ensure inherited interface is declared before using it.

[Eric Pouech]

From: Eric Pouech

If interface I1 inherits from interface I2, midl allows I2 declaration
to appear after I1's declaration in .idl file.
Keeping the .idl order is fine with C binding, but doesn't work for C++
classes (class I2 must be declared before being inherited from).

So ensure inherited interface is declared in header generation before
using it.

Signed-off-by: Eric Pouech 
---
 tools/widl/header.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/tools/widl/header.c b/tools/widl/header.c
index 29c6c32c8f4..f20682f2848 100644
--- a/tools/widl/header.c
+++ b/tools/widl/header.c
@@ -1977,6 +1977,26 @@ static void write_forward_decls(FILE *header, const statement_list_t *stmts)
   }
 }

+static void write_header_stmts( FILE *header, const statement_list_t *stmts, const type_t *iface, int ignore_funcs );
+
+static void write_header_com_interface( FILE *header, type_t *iface, const type_t *ref_iface )
+{
+    type_t *inherit_from;
+
+    if (iface->written) return;
+
+    /* ensure declaration of inherited interface exists before ours (C++ requires this) */
+    inherit_from = type_iface_get_inherit( iface );
+    if (inherit_from && !inherit_from->ignore && type_iface_get_inherit( inherit_from ) /* skip IUnknown */)
+        write_header_com_interface( header, inherit_from, inherit_from );
+
+    write_com_interface_start( header, iface );
+    write_header_stmts( header, type_iface_get_stmts(iface), ref_iface, TRUE );
+    write_com_interface_end( header, iface );
+
+    iface->written = true;
+}
+
 static void write_header_stmts(FILE *header, const statement_list_t *stmts, const type_t *iface, int ignore_funcs)
 {
   const statement_t *stmt;
@@ -1993,9 +2013,7 @@ static void write_header_stmts(FILE *header, const statement_list_t *stmts, cons
           if (is_object(iface)) is_object_interface++;
           if (is_attr(stmt->u.type->attrs, ATTR_DISPINTERFACE) || is_object(stmt->u.type))
           {
-            write_com_interface_start(header, iface);
-            write_header_stmts(header, type_iface_get_stmts(iface), stmt->u.type, TRUE);
-            write_com_interface_end(header, iface);
+            write_header_com_interface(header, iface, stmt->u.type);
             if (async_iface)
             {
               write_com_interface_start(header, async_iface);