Making each output visitor provide its own output collection
function was the only remaining reason for exposing visitor
sub-types to the rest of the code base.  Add a polymorphic
visit_complete() function which is a no-op for input visitors,
and which populates an opaque pointer for output visitors.  For
maximum type-safety, also add a parameter to the output visitor
constructors with a type-correct version of the output pointer,
and assert that the two uses match.
This approach was considered superior to either passing the
output parameter only during construction (action at a distance
during visit_free() feels awkward) or only during visit_complete()
(defeating type safety makes it easier to use incorrectly).
Most callers were function-local, and therefore a mechanical
conversion; the testsuite was a bit trickier, but the previous
cleanup patch minimized the churn here.
The visit_complete() function may be called at most once; doing
so lets us use transfer semantics rather than duplication or
ref-count semantics to get the just-built output back to the
caller, even though it means our behavior is not idempotent.
Generated code is simplified as follows for events:
|@@ -26,7 +26,7 @@ void qapi_event_send_acpi_device_ost(ACP
|     QDict *qmp;
|     Error *err = NULL;
|     QMPEventFuncEmit emit;
|-    QmpOutputVisitor *qov;
|+    QObject *obj;
|     Visitor *v;
|     q_obj_ACPI_DEVICE_OST_arg param = {
|         info
|@@ -39,8 +39,7 @@ void qapi_event_send_acpi_device_ost(ACP
|
|     qmp = qmp_event_build_dict("ACPI_DEVICE_OST");
|
|-    qov = qmp_output_visitor_new();
|-    v = qmp_output_get_visitor(qov);
|+    v = qmp_output_visitor_new(&obj);
|
|     visit_start_struct(v, "ACPI_DEVICE_OST", NULL, 0, &err);
|     if (err) {
|@@ -55,7 +54,8 @@ void qapi_event_send_acpi_device_ost(ACP
|         goto out;
|     }
|
|-    qdict_put_obj(qmp, "data", qmp_output_get_qobject(qov));
|+    visit_complete(v, &obj);
|+    qdict_put_obj(qmp, "data", obj);
|     emit(QAPI_EVENT_ACPI_DEVICE_OST, qmp, &err);
and for commands:
| {
|     Error *err = NULL;
|-    QmpOutputVisitor *qov = qmp_output_visitor_new();
|     Visitor *v;
|
|-    v = qmp_output_get_visitor(qov);
|+    v = qmp_output_visitor_new(ret_out);
|     visit_type_AddfdInfo(v, "unused", &ret_in, &err);
|-    if (err) {
|-        goto out;
|+    if (!err) {
|+        visit_complete(v, ret_out);
|     }
|-    *ret_out = qmp_output_get_qobject(qov);
|-
|-out:
|     error_propagate(errp, err);
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1465490926-28625-13-git-send-email-eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
		
	
			
		
			
				
	
	
		
			301 lines
		
	
	
		
			6.9 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			301 lines
		
	
	
		
			6.9 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
#
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# QAPI command marshaller generator
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#
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# Copyright IBM, Corp. 2011
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# Copyright (C) 2014-2016 Red Hat, Inc.
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#
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# Authors:
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#  Anthony Liguori <aliguori@us.ibm.com>
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#  Michael Roth    <mdroth@linux.vnet.ibm.com>
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#  Markus Armbruster <armbru@redhat.com>
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#
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# This work is licensed under the terms of the GNU GPL, version 2.
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# See the COPYING file in the top-level directory.
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from qapi import *
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import re
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def gen_command_decl(name, arg_type, ret_type):
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    return mcgen('''
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%(c_type)s qmp_%(c_name)s(%(params)s);
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''',
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                 c_type=(ret_type and ret_type.c_type()) or 'void',
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                 c_name=c_name(name),
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                 params=gen_params(arg_type, 'Error **errp'))
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def gen_call(name, arg_type, ret_type):
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    ret = ''
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    argstr = ''
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    if arg_type:
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        assert not arg_type.variants
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        for memb in arg_type.members:
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            if memb.optional:
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                argstr += 'arg.has_%s, ' % c_name(memb.name)
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            argstr += 'arg.%s, ' % c_name(memb.name)
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    lhs = ''
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    if ret_type:
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        lhs = 'retval = '
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    ret = mcgen('''
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    %(lhs)sqmp_%(c_name)s(%(args)s&err);
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''',
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                c_name=c_name(name), args=argstr, lhs=lhs)
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    if ret_type:
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        ret += gen_err_check()
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        ret += mcgen('''
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    qmp_marshal_output_%(c_name)s(retval, ret, &err);
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''',
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                     c_name=ret_type.c_name())
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    return ret
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def gen_marshal_output(ret_type):
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    return mcgen('''
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static void qmp_marshal_output_%(c_name)s(%(c_type)s ret_in, QObject **ret_out, Error **errp)
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{
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    Error *err = NULL;
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    Visitor *v;
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    v = qmp_output_visitor_new(ret_out);
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    visit_type_%(c_name)s(v, "unused", &ret_in, &err);
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    if (!err) {
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        visit_complete(v, ret_out);
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    }
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    error_propagate(errp, err);
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    visit_free(v);
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    v = qapi_dealloc_visitor_new();
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    visit_type_%(c_name)s(v, "unused", &ret_in, NULL);
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    visit_free(v);
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}
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''',
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                 c_type=ret_type.c_type(), c_name=ret_type.c_name())
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def gen_marshal_proto(name):
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    ret = 'void qmp_marshal_%s(QDict *args, QObject **ret, Error **errp)' % c_name(name)
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    if not middle_mode:
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        ret = 'static ' + ret
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    return ret
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def gen_marshal_decl(name):
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    return mcgen('''
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%(proto)s;
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''',
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                 proto=gen_marshal_proto(name))
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def gen_marshal(name, arg_type, ret_type):
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    ret = mcgen('''
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%(proto)s
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{
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    Error *err = NULL;
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''',
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                proto=gen_marshal_proto(name))
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    if ret_type:
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        ret += mcgen('''
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    %(c_type)s retval;
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''',
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                     c_type=ret_type.c_type())
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    if arg_type and arg_type.members:
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        ret += mcgen('''
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    Visitor *v;
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    %(c_name)s arg = {0};
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    v = qmp_input_visitor_new(QOBJECT(args), true);
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    visit_start_struct(v, NULL, NULL, 0, &err);
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    if (err) {
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        goto out;
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    }
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    visit_type_%(c_name)s_members(v, &arg, &err);
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    if (!err) {
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        visit_check_struct(v, &err);
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    }
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    visit_end_struct(v, NULL);
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    if (err) {
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        goto out;
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    }
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''',
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                     c_name=arg_type.c_name())
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    else:
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        ret += mcgen('''
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    (void)args;
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''')
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    ret += gen_call(name, arg_type, ret_type)
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    # 'goto out' produced above for arg_type, and by gen_call() for ret_type
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    if (arg_type and arg_type.members) or ret_type:
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        ret += mcgen('''
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out:
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''')
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    ret += mcgen('''
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    error_propagate(errp, err);
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''')
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    if arg_type and arg_type.members:
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        ret += mcgen('''
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    visit_free(v);
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    v = qapi_dealloc_visitor_new();
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    visit_start_struct(v, NULL, NULL, 0, NULL);
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    visit_type_%(c_name)s_members(v, &arg, NULL);
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    visit_end_struct(v, NULL);
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    visit_free(v);
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''',
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                     c_name=arg_type.c_name())
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    ret += mcgen('''
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}
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''')
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    return ret
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def gen_register_command(name, success_response):
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    options = 'QCO_NO_OPTIONS'
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    if not success_response:
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        options = 'QCO_NO_SUCCESS_RESP'
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    ret = mcgen('''
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    qmp_register_command("%(name)s", qmp_marshal_%(c_name)s, %(opts)s);
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''',
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                name=name, c_name=c_name(name),
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                opts=options)
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    return ret
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def gen_registry(registry):
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    ret = mcgen('''
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static void qmp_init_marshal(void)
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{
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''')
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    ret += registry
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    ret += mcgen('''
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}
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qapi_init(qmp_init_marshal);
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''')
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    return ret
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class QAPISchemaGenCommandVisitor(QAPISchemaVisitor):
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    def __init__(self):
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        self.decl = None
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        self.defn = None
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        self._regy = None
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        self._visited_ret_types = None
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    def visit_begin(self, schema):
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        self.decl = ''
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        self.defn = ''
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        self._regy = ''
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        self._visited_ret_types = set()
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    def visit_end(self):
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        if not middle_mode:
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            self.defn += gen_registry(self._regy)
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        self._regy = None
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        self._visited_ret_types = None
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    def visit_command(self, name, info, arg_type, ret_type,
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                      gen, success_response):
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        if not gen:
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            return
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        self.decl += gen_command_decl(name, arg_type, ret_type)
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        if ret_type and ret_type not in self._visited_ret_types:
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            self._visited_ret_types.add(ret_type)
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            self.defn += gen_marshal_output(ret_type)
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        if middle_mode:
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            self.decl += gen_marshal_decl(name)
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        self.defn += gen_marshal(name, arg_type, ret_type)
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        if not middle_mode:
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            self._regy += gen_register_command(name, success_response)
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middle_mode = False
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(input_file, output_dir, do_c, do_h, prefix, opts) = \
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    parse_command_line("m", ["middle"])
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for o, a in opts:
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    if o in ("-m", "--middle"):
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        middle_mode = True
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c_comment = '''
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/*
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 * schema-defined QMP->QAPI command dispatch
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 *
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 * Copyright IBM, Corp. 2011
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 *
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 * Authors:
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 *  Anthony Liguori   <aliguori@us.ibm.com>
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 *
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 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
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 * See the COPYING.LIB file in the top-level directory.
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 *
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 */
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'''
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h_comment = '''
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/*
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 * schema-defined QAPI function prototypes
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 *
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 * Copyright IBM, Corp. 2011
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 *
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 * Authors:
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 *  Anthony Liguori   <aliguori@us.ibm.com>
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 *
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 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
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 * See the COPYING.LIB file in the top-level directory.
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 *
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 */
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'''
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(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
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                            'qmp-marshal.c', 'qmp-commands.h',
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                            c_comment, h_comment)
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fdef.write(mcgen('''
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#include "qemu/osdep.h"
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#include "qemu-common.h"
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#include "qemu/module.h"
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#include "qapi/qmp/types.h"
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#include "qapi/qmp/dispatch.h"
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#include "qapi/visitor.h"
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#include "qapi/qmp-output-visitor.h"
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#include "qapi/qmp-input-visitor.h"
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#include "qapi/dealloc-visitor.h"
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#include "%(prefix)sqapi-types.h"
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#include "%(prefix)sqapi-visit.h"
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#include "%(prefix)sqmp-commands.h"
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''',
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                 prefix=prefix))
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fdecl.write(mcgen('''
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#include "%(prefix)sqapi-types.h"
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#include "qapi/qmp/qdict.h"
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#include "qapi/error.h"
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''',
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                  prefix=prefix))
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schema = QAPISchema(input_file)
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gen = QAPISchemaGenCommandVisitor()
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schema.visit(gen)
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fdef.write(gen.defn)
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fdecl.write(gen.decl)
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close_output(fdef, fdecl)
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