widl: Support using context handles as the binding handle in client functions.

tools/widl/client.c

@@ -70,6 +70,20 @@ static void check_pointers(const func_t *func)
     }
 }
 
+const var_t* get_context_handle_var(const func_t* func)
+{
+    const var_t* var;
+
+    if (!func->args)
+        return NULL;
+
+    LIST_FOR_EACH_ENTRY( var, func->args, const var_t, entry )
+        if (is_attr(var->attrs, ATTR_IN) && is_context_handle(var->type))
+            return var;
+
+    return NULL;
+}
+
 static void write_function_stubs(type_t *iface, unsigned int *proc_offset)
 {
     const func_t *func;
@@ -85,13 +99,16 @@ static void write_function_stubs(type_t *iface, unsigned int *proc_offset)
     {
         const var_t *def = func->def;
         const var_t* explicit_handle_var;
+        const var_t* context_handle_var = NULL;
         int has_full_pointer = is_full_pointer_function(func);
 
         /* check for a defined binding handle */
         explicit_handle_var = get_explicit_handle_var(func);
+        if (!explicit_handle_var)
+            context_handle_var = get_context_handle_var(func);
         if (explicit_handle)
         {
-            if (!explicit_handle_var)
+            if (!explicit_handle_var || !context_handle_var)
             {
                 error("%s() does not define an explicit binding handle!\n", def->name);
                 return;
@@ -131,7 +148,7 @@ static void write_function_stubs(type_t *iface, unsigned int *proc_offset)
             fprintf(client, " _RetVal;\n");
         }
 
-        if (implicit_handle || explicit_handle_var)
+        if (implicit_handle || explicit_handle_var || context_handle_var)
             print_client("RPC_BINDING_HANDLE _Handle = 0;\n");
 
         print_client("RPC_MESSAGE _RpcMessage;\n");
@@ -172,6 +189,13 @@ static void write_function_stubs(type_t *iface, unsigned int *proc_offset)
             print_client("_Handle = %s;\n", explicit_handle_var->name);
             fprintf(client, "\n");
         }
+        else if (context_handle_var)
+        {
+            print_client("if (%s%s != 0)\n", is_ptr(context_handle_var->type) ? "*" : "", context_handle_var->name);
+            indent++;
+            print_client("_Handle = NDRCContextBinding(%s%s);\n", is_ptr(context_handle_var->type) ? "*" : "", context_handle_var->name);
+            indent--;
+        }
 
         write_remoting_arguments(client, indent, func, PASS_IN, PHASE_BUFFERSIZE);
 
@@ -179,7 +203,7 @@ static void write_function_stubs(type_t *iface, unsigned int *proc_offset)
         indent++;
         print_client("(PMIDL_STUB_MESSAGE)&_StubMsg,\n");
         print_client("_StubMsg.BufferLength,\n");
-        if (implicit_handle || explicit_handle_var)
+        if (implicit_handle || explicit_handle_var || context_handle_var)
             print_client("_Handle);\n");
         else
             print_client("%s__MIDL_AutoBindHandle);\n", iface->name);