qemu-e2k/scripts/qapi-commands.py
Eric Blake 3b098d5697 qapi: Add new visit_complete() function
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>
2016-07-06 10:52:04 +02:00

301 lines
6.9 KiB
Python

#
# QAPI command marshaller generator
#
# Copyright IBM, Corp. 2011
# Copyright (C) 2014-2016 Red Hat, Inc.
#
# Authors:
# Anthony Liguori <aliguori@us.ibm.com>
# Michael Roth <mdroth@linux.vnet.ibm.com>
# Markus Armbruster <armbru@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2.
# See the COPYING file in the top-level directory.
from qapi import *
import re
def gen_command_decl(name, arg_type, ret_type):
return mcgen('''
%(c_type)s qmp_%(c_name)s(%(params)s);
''',
c_type=(ret_type and ret_type.c_type()) or 'void',
c_name=c_name(name),
params=gen_params(arg_type, 'Error **errp'))
def gen_call(name, arg_type, ret_type):
ret = ''
argstr = ''
if arg_type:
assert not arg_type.variants
for memb in arg_type.members:
if memb.optional:
argstr += 'arg.has_%s, ' % c_name(memb.name)
argstr += 'arg.%s, ' % c_name(memb.name)
lhs = ''
if ret_type:
lhs = 'retval = '
ret = mcgen('''
%(lhs)sqmp_%(c_name)s(%(args)s&err);
''',
c_name=c_name(name), args=argstr, lhs=lhs)
if ret_type:
ret += gen_err_check()
ret += mcgen('''
qmp_marshal_output_%(c_name)s(retval, ret, &err);
''',
c_name=ret_type.c_name())
return ret
def gen_marshal_output(ret_type):
return mcgen('''
static void qmp_marshal_output_%(c_name)s(%(c_type)s ret_in, QObject **ret_out, Error **errp)
{
Error *err = NULL;
Visitor *v;
v = qmp_output_visitor_new(ret_out);
visit_type_%(c_name)s(v, "unused", &ret_in, &err);
if (!err) {
visit_complete(v, ret_out);
}
error_propagate(errp, err);
visit_free(v);
v = qapi_dealloc_visitor_new();
visit_type_%(c_name)s(v, "unused", &ret_in, NULL);
visit_free(v);
}
''',
c_type=ret_type.c_type(), c_name=ret_type.c_name())
def gen_marshal_proto(name):
ret = 'void qmp_marshal_%s(QDict *args, QObject **ret, Error **errp)' % c_name(name)
if not middle_mode:
ret = 'static ' + ret
return ret
def gen_marshal_decl(name):
return mcgen('''
%(proto)s;
''',
proto=gen_marshal_proto(name))
def gen_marshal(name, arg_type, ret_type):
ret = mcgen('''
%(proto)s
{
Error *err = NULL;
''',
proto=gen_marshal_proto(name))
if ret_type:
ret += mcgen('''
%(c_type)s retval;
''',
c_type=ret_type.c_type())
if arg_type and arg_type.members:
ret += mcgen('''
Visitor *v;
%(c_name)s arg = {0};
v = qmp_input_visitor_new(QOBJECT(args), true);
visit_start_struct(v, NULL, NULL, 0, &err);
if (err) {
goto out;
}
visit_type_%(c_name)s_members(v, &arg, &err);
if (!err) {
visit_check_struct(v, &err);
}
visit_end_struct(v, NULL);
if (err) {
goto out;
}
''',
c_name=arg_type.c_name())
else:
ret += mcgen('''
(void)args;
''')
ret += gen_call(name, arg_type, ret_type)
# 'goto out' produced above for arg_type, and by gen_call() for ret_type
if (arg_type and arg_type.members) or ret_type:
ret += mcgen('''
out:
''')
ret += mcgen('''
error_propagate(errp, err);
''')
if arg_type and arg_type.members:
ret += mcgen('''
visit_free(v);
v = qapi_dealloc_visitor_new();
visit_start_struct(v, NULL, NULL, 0, NULL);
visit_type_%(c_name)s_members(v, &arg, NULL);
visit_end_struct(v, NULL);
visit_free(v);
''',
c_name=arg_type.c_name())
ret += mcgen('''
}
''')
return ret
def gen_register_command(name, success_response):
options = 'QCO_NO_OPTIONS'
if not success_response:
options = 'QCO_NO_SUCCESS_RESP'
ret = mcgen('''
qmp_register_command("%(name)s", qmp_marshal_%(c_name)s, %(opts)s);
''',
name=name, c_name=c_name(name),
opts=options)
return ret
def gen_registry(registry):
ret = mcgen('''
static void qmp_init_marshal(void)
{
''')
ret += registry
ret += mcgen('''
}
qapi_init(qmp_init_marshal);
''')
return ret
class QAPISchemaGenCommandVisitor(QAPISchemaVisitor):
def __init__(self):
self.decl = None
self.defn = None
self._regy = None
self._visited_ret_types = None
def visit_begin(self, schema):
self.decl = ''
self.defn = ''
self._regy = ''
self._visited_ret_types = set()
def visit_end(self):
if not middle_mode:
self.defn += gen_registry(self._regy)
self._regy = None
self._visited_ret_types = None
def visit_command(self, name, info, arg_type, ret_type,
gen, success_response):
if not gen:
return
self.decl += gen_command_decl(name, arg_type, ret_type)
if ret_type and ret_type not in self._visited_ret_types:
self._visited_ret_types.add(ret_type)
self.defn += gen_marshal_output(ret_type)
if middle_mode:
self.decl += gen_marshal_decl(name)
self.defn += gen_marshal(name, arg_type, ret_type)
if not middle_mode:
self._regy += gen_register_command(name, success_response)
middle_mode = False
(input_file, output_dir, do_c, do_h, prefix, opts) = \
parse_command_line("m", ["middle"])
for o, a in opts:
if o in ("-m", "--middle"):
middle_mode = True
c_comment = '''
/*
* schema-defined QMP->QAPI command dispatch
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
'''
h_comment = '''
/*
* schema-defined QAPI function prototypes
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
'''
(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
'qmp-marshal.c', 'qmp-commands.h',
c_comment, h_comment)
fdef.write(mcgen('''
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qemu/module.h"
#include "qapi/qmp/types.h"
#include "qapi/qmp/dispatch.h"
#include "qapi/visitor.h"
#include "qapi/qmp-output-visitor.h"
#include "qapi/qmp-input-visitor.h"
#include "qapi/dealloc-visitor.h"
#include "%(prefix)sqapi-types.h"
#include "%(prefix)sqapi-visit.h"
#include "%(prefix)sqmp-commands.h"
''',
prefix=prefix))
fdecl.write(mcgen('''
#include "%(prefix)sqapi-types.h"
#include "qapi/qmp/qdict.h"
#include "qapi/error.h"
''',
prefix=prefix))
schema = QAPISchema(input_file)
gen = QAPISchemaGenCommandVisitor()
schema.visit(gen)
fdef.write(gen.defn)
fdecl.write(gen.decl)
close_output(fdef, fdecl)