qapi-gen: New common driver for code and doc generators

Whenever qapi-schema.json changes, we run six programs eleven times to
update eleven files.  Similar for qga/qapi-schema.json.  This is
silly.  Replace the six programs by a single program that spits out
all eleven files.

The programs become modules in new Python package qapi, along with the
helper library.  This requires moving them to scripts/qapi/.  While
moving them, consistently drop executable mode bits.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20180211093607.27351-9-armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
[eblake: move change to one-line 'blurb' earlier in series, mention mode
bit change as intentional, update qapi-code-gen.txt to match actual
generated events.c file]
Signed-off-by: Eric Blake <eblake@redhat.com>

scripts/qapi/commands.py

@@ -0,0 +1,293 @@
+"""
+QAPI command marshaller generator
+
+Copyright IBM, Corp. 2011
+Copyright (C) 2014-2018 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.common import *
+
+
+def gen_command_decl(name, arg_type, boxed, 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=build_params(arg_type, boxed, 'Error **errp'))
+
+
+def gen_call(name, arg_type, boxed, ret_type):
+    ret = ''
+
+    argstr = ''
+    if boxed:
+        assert arg_type and not arg_type.is_empty()
+        argstr = '&arg, '
+    elif 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 += mcgen('''
+    if (err) {
+        goto out;
+    }
+
+    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 = qobject_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 build_marshal_proto(name):
+    return ('void qmp_marshal_%s(QDict *args, QObject **ret, Error **errp)'
+            % c_name(name))
+
+
+def gen_marshal_decl(name):
+    return mcgen('''
+%(proto)s;
+''',
+                 proto=build_marshal_proto(name))
+
+
+def gen_marshal(name, arg_type, boxed, ret_type):
+    have_args = arg_type and not arg_type.is_empty()
+
+    ret = mcgen('''
+
+%(proto)s
+{
+    Error *err = NULL;
+''',
+                proto=build_marshal_proto(name))
+
+    if ret_type:
+        ret += mcgen('''
+    %(c_type)s retval;
+''',
+                     c_type=ret_type.c_type())
+
+    if have_args:
+        visit_members = ('visit_type_%s_members(v, &arg, &err);'
+                         % arg_type.c_name())
+        ret += mcgen('''
+    Visitor *v;
+    %(c_name)s arg = {0};
+
+''',
+                     c_name=arg_type.c_name())
+    else:
+        visit_members = ''
+        ret += mcgen('''
+    Visitor *v = NULL;
+
+    if (args) {
+''')
+        push_indent()
+
+    ret += mcgen('''
+    v = qobject_input_visitor_new(QOBJECT(args));
+    visit_start_struct(v, NULL, NULL, 0, &err);
+    if (err) {
+        goto out;
+    }
+    %(visit_members)s
+    if (!err) {
+        visit_check_struct(v, &err);
+    }
+    visit_end_struct(v, NULL);
+    if (err) {
+        goto out;
+    }
+''',
+                 visit_members=visit_members)
+
+    if not have_args:
+        pop_indent()
+        ret += mcgen('''
+    }
+''')
+
+    ret += gen_call(name, arg_type, boxed, ret_type)
+
+    ret += mcgen('''
+
+out:
+    error_propagate(errp, err);
+    visit_free(v);
+''')
+
+    if have_args:
+        visit_members = ('visit_type_%s_members(v, &arg, NULL);'
+                         % arg_type.c_name())
+    else:
+        visit_members = ''
+        ret += mcgen('''
+    if (args) {
+''')
+        push_indent()
+
+    ret += mcgen('''
+    v = qapi_dealloc_visitor_new();
+    visit_start_struct(v, NULL, NULL, 0, NULL);
+    %(visit_members)s
+    visit_end_struct(v, NULL);
+    visit_free(v);
+''',
+                 visit_members=visit_members)
+
+    if not have_args:
+        pop_indent()
+        ret += mcgen('''
+    }
+''')
+
+    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(cmds, "%(name)s",
+                         qmp_marshal_%(c_name)s, %(opts)s);
+''',
+                name=name, c_name=c_name(name),
+                opts=options)
+    return ret
+
+
+def gen_registry(registry, prefix):
+    ret = mcgen('''
+
+void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds)
+{
+    QTAILQ_INIT(cmds);
+
+''',
+                c_prefix=c_name(prefix, protect=False))
+    ret += registry
+    ret += mcgen('''
+}
+''')
+    return ret
+
+
+class QAPISchemaGenCommandVisitor(QAPISchemaVisitor):
+    def __init__(self, prefix):
+        self._prefix = prefix
+        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):
+        self.defn += gen_registry(self._regy, self._prefix)
+        self._regy = None
+        self._visited_ret_types = None
+
+    def visit_command(self, name, info, arg_type, ret_type,
+                      gen, success_response, boxed):
+        if not gen:
+            return
+        self.decl += gen_command_decl(name, arg_type, boxed, 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)
+        self.decl += gen_marshal_decl(name)
+        self.defn += gen_marshal(name, arg_type, boxed, ret_type)
+        self._regy += gen_register_command(name, success_response)
+
+
+def gen_commands(schema, output_dir, prefix):
+    blurb = ' * Schema-defined QAPI/QMP commands'
+    genc = QAPIGenC(blurb, __doc__)
+    genh = QAPIGenH(blurb, __doc__)
+
+    genc.add(mcgen('''
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qemu/module.h"
+#include "qapi/visitor.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qobject-output-visitor.h"
+#include "qapi/qobject-input-visitor.h"
+#include "qapi/dealloc-visitor.h"
+#include "qapi/error.h"
+#include "%(prefix)sqapi-types.h"
+#include "%(prefix)sqapi-visit.h"
+#include "%(prefix)sqmp-commands.h"
+
+''',
+                   prefix=prefix))
+
+    genh.add(mcgen('''
+#include "%(prefix)sqapi-types.h"
+#include "qapi/qmp/dispatch.h"
+
+void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds);
+''',
+                   prefix=prefix, c_prefix=c_name(prefix, protect=False)))
+
+    vis = QAPISchemaGenCommandVisitor(prefix)
+    schema.visit(vis)
+    genc.add(vis.defn)
+    genh.add(vis.decl)
+    genc.write(output_dir, prefix + 'qmp-marshal.c')
+    genh.write(output_dir, prefix + 'qmp-commands.h')

scripts/qapi/doc.py

@@ -0,0 +1,278 @@
+#!/usr/bin/env python
+# QAPI texi generator
+#
+# This work is licensed under the terms of the GNU LGPL, version 2+.
+# See the COPYING file in the top-level directory.
+"""This script produces the documentation of a qapi schema in texinfo format"""
+
+from __future__ import print_function
+import re
+import qapi.common
+
+MSG_FMT = """
+@deftypefn {type} {{}} {name}
+
+{body}
+@end deftypefn
+
+""".format
+
+TYPE_FMT = """
+@deftp {{{type}}} {name}
+
+{body}
+@end deftp
+
+""".format
+
+EXAMPLE_FMT = """@example
+{code}
+@end example
+""".format
+
+
+def subst_strong(doc):
+    """Replaces *foo* by @strong{foo}"""
+    return re.sub(r'\*([^*\n]+)\*', r'@strong{\1}', doc)
+
+
+def subst_emph(doc):
+    """Replaces _foo_ by @emph{foo}"""
+    return re.sub(r'\b_([^_\n]+)_\b', r'@emph{\1}', doc)
+
+
+def subst_vars(doc):
+    """Replaces @var by @code{var}"""
+    return re.sub(r'@([\w-]+)', r'@code{\1}', doc)
+
+
+def subst_braces(doc):
+    """Replaces {} with @{ @}"""
+    return doc.replace('{', '@{').replace('}', '@}')
+
+
+def texi_example(doc):
+    """Format @example"""
+    # TODO: Neglects to escape @ characters.
+    # We should probably escape them in subst_braces(), and rename the
+    # function to subst_special() or subs_texi_special().  If we do that, we
+    # need to delay it until after subst_vars() in texi_format().
+    doc = subst_braces(doc).strip('\n')
+    return EXAMPLE_FMT(code=doc)
+
+
+def texi_format(doc):
+    """
+    Format documentation
+
+    Lines starting with:
+    - |: generates an @example
+    - =: generates @section
+    - ==: generates @subsection
+    - 1. or 1): generates an @enumerate @item
+    - */-: generates an @itemize list
+    """
+    ret = ''
+    doc = subst_braces(doc)
+    doc = subst_vars(doc)
+    doc = subst_emph(doc)
+    doc = subst_strong(doc)
+    inlist = ''
+    lastempty = False
+    for line in doc.split('\n'):
+        empty = line == ''
+
+        # FIXME: Doing this in a single if / elif chain is
+        # problematic.  For instance, a line without markup terminates
+        # a list if it follows a blank line (reaches the final elif),
+        # but a line with some *other* markup, such as a = title
+        # doesn't.
+        #
+        # Make sure to update section "Documentation markup" in
+        # docs/devel/qapi-code-gen.txt when fixing this.
+        if line.startswith('| '):
+            line = EXAMPLE_FMT(code=line[2:])
+        elif line.startswith('= '):
+            line = '@section ' + line[2:]
+        elif line.startswith('== '):
+            line = '@subsection ' + line[3:]
+        elif re.match(r'^([0-9]*\.) ', line):
+            if not inlist:
+                ret += '@enumerate\n'
+                inlist = 'enumerate'
+            ret += '@item\n'
+            line = line[line.find(' ')+1:]
+        elif re.match(r'^[*-] ', line):
+            if not inlist:
+                ret += '@itemize %s\n' % {'*': '@bullet',
+                                          '-': '@minus'}[line[0]]
+                inlist = 'itemize'
+            ret += '@item\n'
+            line = line[2:]
+        elif lastempty and inlist:
+            ret += '@end %s\n\n' % inlist
+            inlist = ''
+
+        lastempty = empty
+        ret += line + '\n'
+
+    if inlist:
+        ret += '@end %s\n\n' % inlist
+    return ret
+
+
+def texi_body(doc):
+    """Format the main documentation body"""
+    return texi_format(doc.body.text)
+
+
+def texi_enum_value(value):
+    """Format a table of members item for an enumeration value"""
+    return '@item @code{%s}\n' % value.name
+
+
+def texi_member(member, suffix=''):
+    """Format a table of members item for an object type member"""
+    typ = member.type.doc_type()
+    return '@item @code{%s%s%s}%s%s\n' % (
+        member.name,
+        ': ' if typ else '',
+        typ if typ else '',
+        ' (optional)' if member.optional else '',
+        suffix)
+
+
+def texi_members(doc, what, base, variants, member_func):
+    """Format the table of members"""
+    items = ''
+    for section in doc.args.values():
+        # TODO Drop fallbacks when undocumented members are outlawed
+        if section.text:
+            desc = texi_format(section.text)
+        elif (variants and variants.tag_member == section.member
+              and not section.member.type.doc_type()):
+            values = section.member.type.member_names()
+            members_text = ', '.join(['@t{"%s"}' % v for v in values])
+            desc = 'One of ' + members_text + '\n'
+        else:
+            desc = 'Not documented\n'
+        items += member_func(section.member) + desc
+    if base:
+        items += '@item The members of @code{%s}\n' % base.doc_type()
+    if variants:
+        for v in variants.variants:
+            when = ' when @code{%s} is @t{"%s"}' % (
+                variants.tag_member.name, v.name)
+            if v.type.is_implicit():
+                assert not v.type.base and not v.type.variants
+                for m in v.type.local_members:
+                    items += member_func(m, when)
+            else:
+                items += '@item The members of @code{%s}%s\n' % (
+                    v.type.doc_type(), when)
+    if not items:
+        return ''
+    return '\n@b{%s:}\n@table @asis\n%s@end table\n' % (what, items)
+
+
+def texi_sections(doc):
+    """Format additional sections following arguments"""
+    body = ''
+    for section in doc.sections:
+        if section.name:
+            # prefer @b over @strong, so txt doesn't translate it to *Foo:*
+            body += '\n@b{%s:}\n' % section.name
+        if section.name and section.name.startswith('Example'):
+            body += texi_example(section.text)
+        else:
+            body += texi_format(section.text)
+    return body
+
+
+def texi_entity(doc, what, base=None, variants=None,
+                member_func=texi_member):
+    return (texi_body(doc)
+            + texi_members(doc, what, base, variants, member_func)
+            + texi_sections(doc))
+
+
+class QAPISchemaGenDocVisitor(qapi.common.QAPISchemaVisitor):
+    def __init__(self):
+        self.out = None
+        self.cur_doc = None
+
+    def visit_begin(self, schema):
+        self.out = ''
+
+    def visit_enum_type(self, name, info, values, prefix):
+        doc = self.cur_doc
+        self.out += TYPE_FMT(type='Enum',
+                             name=doc.symbol,
+                             body=texi_entity(doc, 'Values',
+                                              member_func=texi_enum_value))
+
+    def visit_object_type(self, name, info, base, members, variants):
+        doc = self.cur_doc
+        if base and base.is_implicit():
+            base = None
+        self.out += TYPE_FMT(type='Object',
+                             name=doc.symbol,
+                             body=texi_entity(doc, 'Members', base, variants))
+
+    def visit_alternate_type(self, name, info, variants):
+        doc = self.cur_doc
+        self.out += TYPE_FMT(type='Alternate',
+                             name=doc.symbol,
+                             body=texi_entity(doc, 'Members'))
+
+    def visit_command(self, name, info, arg_type, ret_type,
+                      gen, success_response, boxed):
+        doc = self.cur_doc
+        if boxed:
+            body = texi_body(doc)
+            body += ('\n@b{Arguments:} the members of @code{%s}\n'
+                     % arg_type.name)
+            body += texi_sections(doc)
+        else:
+            body = texi_entity(doc, 'Arguments')
+        self.out += MSG_FMT(type='Command',
+                            name=doc.symbol,
+                            body=body)
+
+    def visit_event(self, name, info, arg_type, boxed):
+        doc = self.cur_doc
+        self.out += MSG_FMT(type='Event',
+                            name=doc.symbol,
+                            body=texi_entity(doc, 'Arguments'))
+
+    def symbol(self, doc, entity):
+        if self.out:
+            self.out += '\n'
+        self.cur_doc = doc
+        entity.visit(self)
+        self.cur_doc = None
+
+    def freeform(self, doc):
+        assert not doc.args
+        if self.out:
+            self.out += '\n'
+        self.out += texi_body(doc) + texi_sections(doc)
+
+
+def texi_schema(schema):
+    """Convert QAPI schema documentation to Texinfo"""
+    gen = QAPISchemaGenDocVisitor()
+    gen.visit_begin(schema)
+    for doc in schema.docs:
+        if doc.symbol:
+            gen.symbol(doc, schema.lookup_entity(doc.symbol))
+        else:
+            gen.freeform(doc)
+    return gen.out
+
+
+def gen_doc(schema, output_dir, prefix):
+    if qapi.common.doc_required:
+        gen = qapi.common.QAPIGenDoc()
+        gen.add(texi_schema(schema))
+        gen.write(output_dir, prefix + 'qapi-doc.texi')

scripts/qapi/events.py

@@ -0,0 +1,204 @@
+"""
+QAPI event generator
+
+Copyright (c) 2014 Wenchao Xia
+Copyright (c) 2015-2018 Red Hat Inc.
+
+Authors:
+ Wenchao Xia <wenchaoqemu@gmail.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.common import *
+
+
+def build_event_send_proto(name, arg_type, boxed):
+    return 'void qapi_event_send_%(c_name)s(%(param)s)' % {
+        'c_name': c_name(name.lower()),
+        'param': build_params(arg_type, boxed, 'Error **errp')}
+
+
+def gen_event_send_decl(name, arg_type, boxed):
+    return mcgen('''
+
+%(proto)s;
+''',
+                 proto=build_event_send_proto(name, arg_type, boxed))
+
+
+# Declare and initialize an object 'qapi' using parameters from build_params()
+def gen_param_var(typ):
+    assert not typ.variants
+    ret = mcgen('''
+    %(c_name)s param = {
+''',
+                c_name=typ.c_name())
+    sep = '        '
+    for memb in typ.members:
+        ret += sep
+        sep = ', '
+        if memb.optional:
+            ret += 'has_' + c_name(memb.name) + sep
+        if memb.type.name == 'str':
+            # Cast away const added in build_params()
+            ret += '(char *)'
+        ret += c_name(memb.name)
+    ret += mcgen('''
+
+    };
+''')
+    if not typ.is_implicit():
+        ret += mcgen('''
+    %(c_name)s *arg = &param;
+''',
+                     c_name=typ.c_name())
+    return ret
+
+
+def gen_event_send(name, arg_type, boxed, event_enum_name):
+    # FIXME: Our declaration of local variables (and of 'errp' in the
+    # parameter list) can collide with exploded members of the event's
+    # data type passed in as parameters.  If this collision ever hits in
+    # practice, we can rename our local variables with a leading _ prefix,
+    # or split the code into a wrapper function that creates a boxed
+    # 'param' object then calls another to do the real work.
+    ret = mcgen('''
+
+%(proto)s
+{
+    QDict *qmp;
+    Error *err = NULL;
+    QMPEventFuncEmit emit;
+''',
+                proto=build_event_send_proto(name, arg_type, boxed))
+
+    if arg_type and not arg_type.is_empty():
+        ret += mcgen('''
+    QObject *obj;
+    Visitor *v;
+''')
+        if not boxed:
+            ret += gen_param_var(arg_type)
+    else:
+        assert not boxed
+
+    ret += mcgen('''
+
+    emit = qmp_event_get_func_emit();
+    if (!emit) {
+        return;
+    }
+
+    qmp = qmp_event_build_dict("%(name)s");
+
+''',
+                 name=name)
+
+    if arg_type and not arg_type.is_empty():
+        ret += mcgen('''
+    v = qobject_output_visitor_new(&obj);
+''')
+        if not arg_type.is_implicit():
+            ret += mcgen('''
+    visit_type_%(c_name)s(v, "%(name)s", &arg, &err);
+''',
+                         name=name, c_name=arg_type.c_name())
+        else:
+            ret += mcgen('''
+
+    visit_start_struct(v, "%(name)s", NULL, 0, &err);
+    if (err) {
+        goto out;
+    }
+    visit_type_%(c_name)s_members(v, &param, &err);
+    if (!err) {
+        visit_check_struct(v, &err);
+    }
+    visit_end_struct(v, NULL);
+''',
+                         name=name, c_name=arg_type.c_name())
+        ret += mcgen('''
+    if (err) {
+        goto out;
+    }
+
+    visit_complete(v, &obj);
+    qdict_put_obj(qmp, "data", obj);
+''')
+
+    ret += mcgen('''
+    emit(%(c_enum)s, qmp, &err);
+
+''',
+                 c_enum=c_enum_const(event_enum_name, name))
+
+    if arg_type and not arg_type.is_empty():
+        ret += mcgen('''
+out:
+    visit_free(v);
+''')
+    ret += mcgen('''
+    error_propagate(errp, err);
+    QDECREF(qmp);
+}
+''')
+    return ret
+
+
+class QAPISchemaGenEventVisitor(QAPISchemaVisitor):
+    def __init__(self, prefix):
+        self._enum_name = c_name(prefix + 'QAPIEvent', protect=False)
+        self.decl = None
+        self.defn = None
+        self._event_names = None
+
+    def visit_begin(self, schema):
+        self.decl = ''
+        self.defn = ''
+        self._event_names = []
+
+    def visit_end(self):
+        self.decl += gen_enum(self._enum_name, self._event_names)
+        self.defn += gen_enum_lookup(self._enum_name, self._event_names)
+        self._event_names = None
+
+    def visit_event(self, name, info, arg_type, boxed):
+        self.decl += gen_event_send_decl(name, arg_type, boxed)
+        self.defn += gen_event_send(name, arg_type, boxed, self._enum_name)
+        self._event_names.append(name)
+
+
+def gen_events(schema, output_dir, prefix):
+    blurb = ' * Schema-defined QAPI/QMP events'
+    genc = QAPIGenC(blurb, __doc__)
+    genh = QAPIGenH(blurb, __doc__)
+
+    genc.add(mcgen('''
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "%(prefix)sqapi-event.h"
+#include "%(prefix)sqapi-visit.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qobject-output-visitor.h"
+#include "qapi/qmp-event.h"
+
+''',
+                   prefix=prefix))
+
+    genh.add(mcgen('''
+#include "qapi/util.h"
+#include "%(prefix)sqapi-types.h"
+
+''',
+                   prefix=prefix))
+
+    vis = QAPISchemaGenEventVisitor(prefix)
+    schema.visit(vis)
+    genc.add(vis.defn)
+    genh.add(vis.decl)
+    genc.write(output_dir, prefix + 'qapi-event.c')
+    genh.write(output_dir, prefix + 'qapi-event.h')

scripts/qapi/introspect.py

@@ -0,0 +1,188 @@
+"""
+QAPI introspection generator
+
+Copyright (C) 2015-2018 Red Hat, Inc.
+
+Authors:
+ 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.common import *
+
+
+# Caveman's json.dumps() replacement (we're stuck at Python 2.4)
+# TODO try to use json.dumps() once we get unstuck
+def to_json(obj, level=0):
+    if obj is None:
+        ret = 'null'
+    elif isinstance(obj, str):
+        ret = '"' + obj.replace('"', r'\"') + '"'
+    elif isinstance(obj, list):
+        elts = [to_json(elt, level + 1)
+                for elt in obj]
+        ret = '[' + ', '.join(elts) + ']'
+    elif isinstance(obj, dict):
+        elts = ['"%s": %s' % (key.replace('"', r'\"'),
+                              to_json(obj[key], level + 1))
+                for key in sorted(obj.keys())]
+        ret = '{' + ', '.join(elts) + '}'
+    else:
+        assert False                # not implemented
+    if level == 1:
+        ret = '\n' + ret
+    return ret
+
+
+def to_c_string(string):
+    return '"' + string.replace('\\', r'\\').replace('"', r'\"') + '"'
+
+
+class QAPISchemaGenIntrospectVisitor(QAPISchemaVisitor):
+    def __init__(self, prefix, unmask):
+        self._prefix = prefix
+        self._unmask = unmask
+        self.defn = None
+        self.decl = None
+        self._schema = None
+        self._jsons = None
+        self._used_types = None
+        self._name_map = None
+
+    def visit_begin(self, schema):
+        self._schema = schema
+        self._jsons = []
+        self._used_types = []
+        self._name_map = {}
+
+    def visit_end(self):
+        # visit the types that are actually used
+        jsons = self._jsons
+        self._jsons = []
+        for typ in self._used_types:
+            typ.visit(self)
+        # generate C
+        # TODO can generate awfully long lines
+        jsons.extend(self._jsons)
+        name = c_name(self._prefix, protect=False) + 'qmp_schema_json'
+        self.decl = mcgen('''
+extern const char %(c_name)s[];
+''',
+                          c_name=c_name(name))
+        lines = to_json(jsons).split('\n')
+        c_string = '\n    '.join([to_c_string(line) for line in lines])
+        self.defn = mcgen('''
+const char %(c_name)s[] = %(c_string)s;
+''',
+                          c_name=c_name(name),
+                          c_string=c_string)
+        self._schema = None
+        self._jsons = None
+        self._used_types = None
+        self._name_map = None
+
+    def visit_needed(self, entity):
+        # Ignore types on first pass; visit_end() will pick up used types
+        return not isinstance(entity, QAPISchemaType)
+
+    def _name(self, name):
+        if self._unmask:
+            return name
+        if name not in self._name_map:
+            self._name_map[name] = '%d' % len(self._name_map)
+        return self._name_map[name]
+
+    def _use_type(self, typ):
+        # Map the various integer types to plain int
+        if typ.json_type() == 'int':
+            typ = self._schema.lookup_type('int')
+        elif (isinstance(typ, QAPISchemaArrayType) and
+              typ.element_type.json_type() == 'int'):
+            typ = self._schema.lookup_type('intList')
+        # Add type to work queue if new
+        if typ not in self._used_types:
+            self._used_types.append(typ)
+        # Clients should examine commands and events, not types.  Hide
+        # type names to reduce the temptation.  Also saves a few
+        # characters.
+        if isinstance(typ, QAPISchemaBuiltinType):
+            return typ.name
+        if isinstance(typ, QAPISchemaArrayType):
+            return '[' + self._use_type(typ.element_type) + ']'
+        return self._name(typ.name)
+
+    def _gen_json(self, name, mtype, obj):
+        if mtype not in ('command', 'event', 'builtin', 'array'):
+            name = self._name(name)
+        obj['name'] = name
+        obj['meta-type'] = mtype
+        self._jsons.append(obj)
+
+    def _gen_member(self, member):
+        ret = {'name': member.name, 'type': self._use_type(member.type)}
+        if member.optional:
+            ret['default'] = None
+        return ret
+
+    def _gen_variants(self, tag_name, variants):
+        return {'tag': tag_name,
+                'variants': [self._gen_variant(v) for v in variants]}
+
+    def _gen_variant(self, variant):
+        return {'case': variant.name, 'type': self._use_type(variant.type)}
+
+    def visit_builtin_type(self, name, info, json_type):
+        self._gen_json(name, 'builtin', {'json-type': json_type})
+
+    def visit_enum_type(self, name, info, values, prefix):
+        self._gen_json(name, 'enum', {'values': values})
+
+    def visit_array_type(self, name, info, element_type):
+        element = self._use_type(element_type)
+        self._gen_json('[' + element + ']', 'array', {'element-type': element})
+
+    def visit_object_type_flat(self, name, info, members, variants):
+        obj = {'members': [self._gen_member(m) for m in members]}
+        if variants:
+            obj.update(self._gen_variants(variants.tag_member.name,
+                                          variants.variants))
+        self._gen_json(name, 'object', obj)
+
+    def visit_alternate_type(self, name, info, variants):
+        self._gen_json(name, 'alternate',
+                       {'members': [{'type': self._use_type(m.type)}
+                                    for m in variants.variants]})
+
+    def visit_command(self, name, info, arg_type, ret_type,
+                      gen, success_response, boxed):
+        arg_type = arg_type or self._schema.the_empty_object_type
+        ret_type = ret_type or self._schema.the_empty_object_type
+        self._gen_json(name, 'command',
+                       {'arg-type': self._use_type(arg_type),
+                        'ret-type': self._use_type(ret_type)})
+
+    def visit_event(self, name, info, arg_type, boxed):
+        arg_type = arg_type or self._schema.the_empty_object_type
+        self._gen_json(name, 'event', {'arg-type': self._use_type(arg_type)})
+
+
+def gen_introspect(schema, output_dir, prefix, opt_unmask):
+    blurb = ' * QAPI/QMP schema introspection'
+    genc = QAPIGenC(blurb, __doc__)
+    genh = QAPIGenH(blurb, __doc__)
+
+    genc.add(mcgen('''
+#include "qemu/osdep.h"
+#include "%(prefix)sqmp-introspect.h"
+
+''',
+                   prefix=prefix))
+
+    vis = QAPISchemaGenIntrospectVisitor(prefix, opt_unmask)
+    schema.visit(vis)
+    genc.add(vis.defn)
+    genh.add(vis.decl)
+    genc.write(output_dir, prefix + 'qmp-introspect.c')
+    genh.write(output_dir, prefix + 'qmp-introspect.h')

scripts/qapi/types.py

@@ -0,0 +1,266 @@
+"""
+QAPI types generator
+
+Copyright IBM, Corp. 2011
+Copyright (c) 2013-2018 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.common import *
+
+
+# variants must be emitted before their container; track what has already
+# been output
+objects_seen = set()
+
+
+def gen_fwd_object_or_array(name):
+    return mcgen('''
+
+typedef struct %(c_name)s %(c_name)s;
+''',
+                 c_name=c_name(name))
+
+
+def gen_array(name, element_type):
+    return mcgen('''
+
+struct %(c_name)s {
+    %(c_name)s *next;
+    %(c_type)s value;
+};
+''',
+                 c_name=c_name(name), c_type=element_type.c_type())
+
+
+def gen_struct_members(members):
+    ret = ''
+    for memb in members:
+        if memb.optional:
+            ret += mcgen('''
+    bool has_%(c_name)s;
+''',
+                         c_name=c_name(memb.name))
+        ret += mcgen('''
+    %(c_type)s %(c_name)s;
+''',
+                     c_type=memb.type.c_type(), c_name=c_name(memb.name))
+    return ret
+
+
+def gen_object(name, base, members, variants):
+    if name in objects_seen:
+        return ''
+    objects_seen.add(name)
+
+    ret = ''
+    if variants:
+        for v in variants.variants:
+            if isinstance(v.type, QAPISchemaObjectType):
+                ret += gen_object(v.type.name, v.type.base,
+                                  v.type.local_members, v.type.variants)
+
+    ret += mcgen('''
+
+struct %(c_name)s {
+''',
+                 c_name=c_name(name))
+
+    if base:
+        if not base.is_implicit():
+            ret += mcgen('''
+    /* Members inherited from %(c_name)s: */
+''',
+                         c_name=base.c_name())
+        ret += gen_struct_members(base.members)
+        if not base.is_implicit():
+            ret += mcgen('''
+    /* Own members: */
+''')
+    ret += gen_struct_members(members)
+
+    if variants:
+        ret += gen_variants(variants)
+
+    # Make sure that all structs have at least one member; this avoids
+    # potential issues with attempting to malloc space for zero-length
+    # structs in C, and also incompatibility with C++ (where an empty
+    # struct is size 1).
+    if (not base or base.is_empty()) and not members and not variants:
+        ret += mcgen('''
+    char qapi_dummy_for_empty_struct;
+''')
+
+    ret += mcgen('''
+};
+''')
+
+    return ret
+
+
+def gen_upcast(name, base):
+    # C makes const-correctness ugly.  We have to cast away const to let
+    # this function work for both const and non-const obj.
+    return mcgen('''
+
+static inline %(base)s *qapi_%(c_name)s_base(const %(c_name)s *obj)
+{
+    return (%(base)s *)obj;
+}
+''',
+                 c_name=c_name(name), base=base.c_name())
+
+
+def gen_variants(variants):
+    ret = mcgen('''
+    union { /* union tag is @%(c_name)s */
+''',
+                c_name=c_name(variants.tag_member.name))
+
+    for var in variants.variants:
+        ret += mcgen('''
+        %(c_type)s %(c_name)s;
+''',
+                     c_type=var.type.c_unboxed_type(),
+                     c_name=c_name(var.name))
+
+    ret += mcgen('''
+    } u;
+''')
+
+    return ret
+
+
+def gen_type_cleanup_decl(name):
+    ret = mcgen('''
+
+void qapi_free_%(c_name)s(%(c_name)s *obj);
+''',
+                c_name=c_name(name))
+    return ret
+
+
+def gen_type_cleanup(name):
+    ret = mcgen('''
+
+void qapi_free_%(c_name)s(%(c_name)s *obj)
+{
+    Visitor *v;
+
+    if (!obj) {
+        return;
+    }
+
+    v = qapi_dealloc_visitor_new();
+    visit_type_%(c_name)s(v, NULL, &obj, NULL);
+    visit_free(v);
+}
+''',
+                c_name=c_name(name))
+    return ret
+
+
+class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
+    def __init__(self, opt_builtins):
+        self._opt_builtins = opt_builtins
+        self.decl = None
+        self.defn = None
+        self._fwdecl = None
+        self._btin = None
+
+    def visit_begin(self, schema):
+        # gen_object() is recursive, ensure it doesn't visit the empty type
+        objects_seen.add(schema.the_empty_object_type.name)
+        self.decl = ''
+        self.defn = ''
+        self._fwdecl = ''
+        self._btin = '\n' + guardstart('QAPI_TYPES_BUILTIN')
+
+    def visit_end(self):
+        self.decl = self._fwdecl + self.decl
+        self._fwdecl = None
+        # To avoid header dependency hell, we always generate
+        # declarations for built-in types in our header files and
+        # simply guard them.  See also opt_builtins (command line
+        # option -b).
+        self._btin += guardend('QAPI_TYPES_BUILTIN')
+        self.decl = self._btin + self.decl
+        self._btin = None
+
+    def _gen_type_cleanup(self, name):
+        self.decl += gen_type_cleanup_decl(name)
+        self.defn += gen_type_cleanup(name)
+
+    def visit_enum_type(self, name, info, values, prefix):
+        # Special case for our lone builtin enum type
+        # TODO use something cleaner than existence of info
+        if not info:
+            self._btin += gen_enum(name, values, prefix)
+            if self._opt_builtins:
+                self.defn += gen_enum_lookup(name, values, prefix)
+        else:
+            self._fwdecl += gen_enum(name, values, prefix)
+            self.defn += gen_enum_lookup(name, values, prefix)
+
+    def visit_array_type(self, name, info, element_type):
+        if isinstance(element_type, QAPISchemaBuiltinType):
+            self._btin += gen_fwd_object_or_array(name)
+            self._btin += gen_array(name, element_type)
+            self._btin += gen_type_cleanup_decl(name)
+            if self._opt_builtins:
+                self.defn += gen_type_cleanup(name)
+        else:
+            self._fwdecl += gen_fwd_object_or_array(name)
+            self.decl += gen_array(name, element_type)
+            self._gen_type_cleanup(name)
+
+    def visit_object_type(self, name, info, base, members, variants):
+        # Nothing to do for the special empty builtin
+        if name == 'q_empty':
+            return
+        self._fwdecl += gen_fwd_object_or_array(name)
+        self.decl += gen_object(name, base, members, variants)
+        if base and not base.is_implicit():
+            self.decl += gen_upcast(name, base)
+        # TODO Worth changing the visitor signature, so we could
+        # directly use rather than repeat type.is_implicit()?
+        if not name.startswith('q_'):
+            # implicit types won't be directly allocated/freed
+            self._gen_type_cleanup(name)
+
+    def visit_alternate_type(self, name, info, variants):
+        self._fwdecl += gen_fwd_object_or_array(name)
+        self.decl += gen_object(name, None, [variants.tag_member], variants)
+        self._gen_type_cleanup(name)
+
+
+def gen_types(schema, output_dir, prefix, opt_builtins):
+    blurb = ' * Schema-defined QAPI types'
+    genc = QAPIGenC(blurb, __doc__)
+    genh = QAPIGenH(blurb, __doc__)
+
+    genc.add(mcgen('''
+#include "qemu/osdep.h"
+#include "qapi/dealloc-visitor.h"
+#include "%(prefix)sqapi-types.h"
+#include "%(prefix)sqapi-visit.h"
+''',
+                   prefix=prefix))
+
+    genh.add(mcgen('''
+#include "qapi/util.h"
+'''))
+
+    vis = QAPISchemaGenTypeVisitor(opt_builtins)
+    schema.visit(vis)
+    genc.add(vis.defn)
+    genh.add(vis.decl)
+    genc.write(output_dir, prefix + 'qapi-types.c')
+    genh.write(output_dir, prefix + 'qapi-types.h')

scripts/qapi/visit.py

@@ -0,0 +1,353 @@
+"""
+QAPI visitor generator
+
+Copyright IBM, Corp. 2011
+Copyright (C) 2014-2018 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.common import *
+
+
+def gen_visit_decl(name, scalar=False):
+    c_type = c_name(name) + ' *'
+    if not scalar:
+        c_type += '*'
+    return mcgen('''
+void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_type)sobj, Error **errp);
+''',
+                 c_name=c_name(name), c_type=c_type)
+
+
+def gen_visit_members_decl(name):
+    return mcgen('''
+
+void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp);
+''',
+                 c_name=c_name(name))
+
+
+def gen_visit_object_members(name, base, members, variants):
+    ret = mcgen('''
+
+void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
+{
+    Error *err = NULL;
+
+''',
+                c_name=c_name(name))
+
+    if base:
+        ret += mcgen('''
+    visit_type_%(c_type)s_members(v, (%(c_type)s *)obj, &err);
+    if (err) {
+        goto out;
+    }
+''',
+                     c_type=base.c_name())
+
+    for memb in members:
+        if memb.optional:
+            ret += mcgen('''
+    if (visit_optional(v, "%(name)s", &obj->has_%(c_name)s)) {
+''',
+                         name=memb.name, c_name=c_name(memb.name))
+            push_indent()
+        ret += mcgen('''
+    visit_type_%(c_type)s(v, "%(name)s", &obj->%(c_name)s, &err);
+    if (err) {
+        goto out;
+    }
+''',
+                     c_type=memb.type.c_name(), name=memb.name,
+                     c_name=c_name(memb.name))
+        if memb.optional:
+            pop_indent()
+            ret += mcgen('''
+    }
+''')
+
+    if variants:
+        ret += mcgen('''
+    switch (obj->%(c_name)s) {
+''',
+                     c_name=c_name(variants.tag_member.name))
+
+        for var in variants.variants:
+            ret += mcgen('''
+    case %(case)s:
+        visit_type_%(c_type)s_members(v, &obj->u.%(c_name)s, &err);
+        break;
+''',
+                         case=c_enum_const(variants.tag_member.type.name,
+                                           var.name,
+                                           variants.tag_member.type.prefix),
+                         c_type=var.type.c_name(), c_name=c_name(var.name))
+
+        ret += mcgen('''
+    default:
+        abort();
+    }
+''')
+
+    # 'goto out' produced for base, for each member, and if variants were
+    # present
+    if base or members or variants:
+        ret += mcgen('''
+
+out:
+''')
+    ret += mcgen('''
+    error_propagate(errp, err);
+}
+''')
+    return ret
+
+
+def gen_visit_list(name, element_type):
+    return mcgen('''
+
+void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
+{
+    Error *err = NULL;
+    %(c_name)s *tail;
+    size_t size = sizeof(**obj);
+
+    visit_start_list(v, name, (GenericList **)obj, size, &err);
+    if (err) {
+        goto out;
+    }
+
+    for (tail = *obj; tail;
+         tail = (%(c_name)s *)visit_next_list(v, (GenericList *)tail, size)) {
+        visit_type_%(c_elt_type)s(v, NULL, &tail->value, &err);
+        if (err) {
+            break;
+        }
+    }
+
+    if (!err) {
+        visit_check_list(v, &err);
+    }
+    visit_end_list(v, (void **)obj);
+    if (err && visit_is_input(v)) {
+        qapi_free_%(c_name)s(*obj);
+        *obj = NULL;
+    }
+out:
+    error_propagate(errp, err);
+}
+''',
+                 c_name=c_name(name), c_elt_type=element_type.c_name())
+
+
+def gen_visit_enum(name):
+    return mcgen('''
+
+void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s *obj, Error **errp)
+{
+    int value = *obj;
+    visit_type_enum(v, name, &value, &%(c_name)s_lookup, errp);
+    *obj = value;
+}
+''',
+                 c_name=c_name(name))
+
+
+def gen_visit_alternate(name, variants):
+    ret = mcgen('''
+
+void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
+{
+    Error *err = NULL;
+
+    visit_start_alternate(v, name, (GenericAlternate **)obj, sizeof(**obj),
+                          &err);
+    if (err) {
+        goto out;
+    }
+    if (!*obj) {
+        goto out_obj;
+    }
+    switch ((*obj)->type) {
+''',
+                 c_name=c_name(name))
+
+    for var in variants.variants:
+        ret += mcgen('''
+    case %(case)s:
+''',
+                     case=var.type.alternate_qtype())
+        if isinstance(var.type, QAPISchemaObjectType):
+            ret += mcgen('''
+        visit_start_struct(v, name, NULL, 0, &err);
+        if (err) {
+            break;
+        }
+        visit_type_%(c_type)s_members(v, &(*obj)->u.%(c_name)s, &err);
+        if (!err) {
+            visit_check_struct(v, &err);
+        }
+        visit_end_struct(v, NULL);
+''',
+                         c_type=var.type.c_name(),
+                         c_name=c_name(var.name))
+        else:
+            ret += mcgen('''
+        visit_type_%(c_type)s(v, name, &(*obj)->u.%(c_name)s, &err);
+''',
+                         c_type=var.type.c_name(),
+                         c_name=c_name(var.name))
+        ret += mcgen('''
+        break;
+''')
+
+    ret += mcgen('''
+    case QTYPE_NONE:
+        abort();
+    default:
+        error_setg(&err, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                   "%(name)s");
+    }
+out_obj:
+    visit_end_alternate(v, (void **)obj);
+    if (err && visit_is_input(v)) {
+        qapi_free_%(c_name)s(*obj);
+        *obj = NULL;
+    }
+out:
+    error_propagate(errp, err);
+}
+''',
+                 name=name, c_name=c_name(name))
+
+    return ret
+
+
+def gen_visit_object(name, base, members, variants):
+    return mcgen('''
+
+void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
+{
+    Error *err = NULL;
+
+    visit_start_struct(v, name, (void **)obj, sizeof(%(c_name)s), &err);
+    if (err) {
+        goto out;
+    }
+    if (!*obj) {
+        goto out_obj;
+    }
+    visit_type_%(c_name)s_members(v, *obj, &err);
+    if (err) {
+        goto out_obj;
+    }
+    visit_check_struct(v, &err);
+out_obj:
+    visit_end_struct(v, (void **)obj);
+    if (err && visit_is_input(v)) {
+        qapi_free_%(c_name)s(*obj);
+        *obj = NULL;
+    }
+out:
+    error_propagate(errp, err);
+}
+''',
+                 c_name=c_name(name))
+
+
+class QAPISchemaGenVisitVisitor(QAPISchemaVisitor):
+    def __init__(self, opt_builtins):
+        self._opt_builtins = opt_builtins
+        self.decl = None
+        self.defn = None
+        self._btin = None
+
+    def visit_begin(self, schema):
+        self.decl = ''
+        self.defn = ''
+        self._btin = '\n' + guardstart('QAPI_VISIT_BUILTIN')
+
+    def visit_end(self):
+        # To avoid header dependency hell, we always generate
+        # declarations for built-in types in our header files and
+        # simply guard them.  See also opt_builtins (command line
+        # option -b).
+        self._btin += guardend('QAPI_VISIT_BUILTIN')
+        self.decl = self._btin + self.decl
+        self._btin = None
+
+    def visit_enum_type(self, name, info, values, prefix):
+        # Special case for our lone builtin enum type
+        # TODO use something cleaner than existence of info
+        if not info:
+            self._btin += gen_visit_decl(name, scalar=True)
+            if self._opt_builtins:
+                self.defn += gen_visit_enum(name)
+        else:
+            self.decl += gen_visit_decl(name, scalar=True)
+            self.defn += gen_visit_enum(name)
+
+    def visit_array_type(self, name, info, element_type):
+        decl = gen_visit_decl(name)
+        defn = gen_visit_list(name, element_type)
+        if isinstance(element_type, QAPISchemaBuiltinType):
+            self._btin += decl
+            if self._opt_builtins:
+                self.defn += defn
+        else:
+            self.decl += decl
+            self.defn += defn
+
+    def visit_object_type(self, name, info, base, members, variants):
+        # Nothing to do for the special empty builtin
+        if name == 'q_empty':
+            return
+        self.decl += gen_visit_members_decl(name)
+        self.defn += gen_visit_object_members(name, base, members, variants)
+        # TODO Worth changing the visitor signature, so we could
+        # directly use rather than repeat type.is_implicit()?
+        if not name.startswith('q_'):
+            # only explicit types need an allocating visit
+            self.decl += gen_visit_decl(name)
+            self.defn += gen_visit_object(name, base, members, variants)
+
+    def visit_alternate_type(self, name, info, variants):
+        self.decl += gen_visit_decl(name)
+        self.defn += gen_visit_alternate(name, variants)
+
+
+def gen_visit(schema, output_dir, prefix, opt_builtins):
+    blurb = ' * Schema-defined QAPI visitors'
+    genc = QAPIGenC(blurb, __doc__)
+    genh = QAPIGenH(blurb, __doc__)
+
+    genc.add(mcgen('''
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qerror.h"
+#include "%(prefix)sqapi-visit.h"
+''',
+                   prefix=prefix))
+
+    genh.add(mcgen('''
+#include "qapi/visitor.h"
+#include "%(prefix)sqapi-types.h"
+
+''',
+                   prefix=prefix))
+
+    vis = QAPISchemaGenVisitVisitor(opt_builtins)
+    schema.visit(vis)
+    genc.add(vis.defn)
+    genh.add(vis.decl)
+    genc.write(output_dir, prefix + 'qapi-visit.c')
+    genh.write(output_dir, prefix + 'qapi-visit.h')