From patchwork Tue Jul 23 13:03:15 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 261083 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id C5B682C00CF for ; Tue, 23 Jul 2013 23:25:17 +1000 (EST) Received: from localhost ([::1]:51132 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V1cK6-0006Qe-S2 for incoming@patchwork.ozlabs.org; Tue, 23 Jul 2013 09:08:14 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54395) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V1cFu-0000HM-7r for qemu-devel@nongnu.org; Tue, 23 Jul 2013 09:03:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V1cFo-0007SR-51 for qemu-devel@nongnu.org; Tue, 23 Jul 2013 09:03:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59350) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V1cFn-0007SJ-PE for qemu-devel@nongnu.org; Tue, 23 Jul 2013 09:03:47 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r6ND3lk9018763 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 23 Jul 2013 09:03:47 -0400 Received: from dhcp-200-207.str.redhat.com (ovpn-116-56.ams2.redhat.com [10.36.116.56]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id r6ND3U6F008625; Tue, 23 Jul 2013 09:03:45 -0400 From: Kevin Wolf To: qemu-devel@nongnu.org Date: Tue, 23 Jul 2013 15:03:15 +0200 Message-Id: <1374584606-5615-8-git-send-email-kwolf@redhat.com> In-Reply-To: <1374584606-5615-1-git-send-email-kwolf@redhat.com> References: <1374584606-5615-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: kwolf@redhat.com, armbru@redhat.com, stefanha@redhat.com, lcapitulino@redhat.com Subject: [Qemu-devel] [PATCH 07/18] qapi: Flat unions with arbitrary discriminator X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Instead of the rather verbose syntax that distinguishes base and subclass fields... { "type": "file", "read-only": true, "data": { "filename": "test" } } ...we can now have both in the same namespace, allowing a more direct mapping of the command line, and moving fields between the common base and subclasses without breaking the API: { "driver": "file", "read-only": true, "filename": "test" } Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake --- docs/qapi-code-gen.txt | 22 +++++++++++++ scripts/qapi-types.py | 6 ++++ scripts/qapi-visit.py | 86 ++++++++++++++++++++++++++++++++++++-------------- 3 files changed, 91 insertions(+), 23 deletions(-) diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt index 555ca66..c187fda 100644 --- a/docs/qapi-code-gen.txt +++ b/docs/qapi-code-gen.txt @@ -103,6 +103,28 @@ And it looks like this on the wire: "data" : { "backing-file": "/some/place/my-image", "lazy-refcounts": true } } + +Flat union types avoid the nesting on the wire. They are used whenever a +specific field of the base type is declared as the discriminator ('type' is +then no longer generated). The discriminator must always be a string field. +The above example can then be modified as follows: + + { 'type': 'BlockdevCommonOptions', + 'data': { 'driver': 'str' 'readonly': 'bool' } } + { 'union': 'BlockdevOptions', + 'base': 'BlockdevCommonOptions', + 'discriminator': 'driver', + 'data': { 'raw': 'RawOptions', + 'qcow2': 'Qcow2Options' } } + +Resulting in this JSON object: + + { "driver": "qcow2", + "readonly": false, + "backing-file": "/some/place/my-image", + "lazy-refcounts": true } + + === Commands === Commands are defined by using a list containing three members. The first diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py index 9882b95..db2f533 100644 --- a/scripts/qapi-types.py +++ b/scripts/qapi-types.py @@ -161,7 +161,9 @@ def generate_union(expr): name = expr['union'] typeinfo = expr['data'] + base = expr.get('base') + discriminator = expr.get('discriminator') ret = mcgen(''' struct %(name)s @@ -185,7 +187,11 @@ struct %(name)s if base: struct = find_struct(base) + if discriminator: + del struct['data'][discriminator] ret += generate_struct_fields(struct['data']) + else: + assert not discriminator ret += mcgen(''' }; diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py index db6fa44..cd33e44 100644 --- a/scripts/qapi-visit.py +++ b/scripts/qapi-visit.py @@ -17,8 +17,26 @@ import os import getopt import errno -def generate_visit_struct_fields(field_prefix, members): +def generate_visit_struct_fields(name, field_prefix, members): + substructs = [] ret = '' + full_name = name if not field_prefix else "%s_%s" % (name, field_prefix) + + for argname, argentry, optional, structured in parse_args(members): + if structured: + ret += generate_visit_struct_fields(name, field_prefix + argname, argentry) + + ret += mcgen(''' + +static void visit_type_%(full_name)s_fields(Visitor *m, %(name)s ** obj, Error **errp) +{ + Error *err = NULL; +''', + name=name, full_name=full_name) + push_indent() + + if len(field_prefix): + field_prefix = field_prefix + "." for argname, argentry, optional, structured in parse_args(members): if optional: @@ -31,7 +49,7 @@ if (obj && (*obj)->%(prefix)shas_%(c_name)s) { push_indent() if structured: - ret += generate_visit_struct_body(field_prefix + argname, argname, argentry) + ret += generate_visit_struct_body(full_name, argname, argentry) else: ret += mcgen(''' visit_type_%(type)s(m, obj ? &(*obj)->%(c_prefix)s%(c_name)s : NULL, "%(name)s", &err); @@ -47,6 +65,12 @@ visit_type_%(type)s(m, obj ? &(*obj)->%(c_prefix)s%(c_name)s : NULL, "%(name)s", visit_end_optional(m, &err); ''') + pop_indent() + ret += mcgen(''' + + error_propagate(errp, err); +} +''') return ret @@ -56,8 +80,9 @@ if (!error_is_set(errp)) { ''') push_indent() + full_name = name if not field_prefix else "%s_%s" % (field_prefix, name) + if len(field_prefix): - field_prefix = field_prefix + "." ret += mcgen(''' Error **errp = &err; /* from outer scope */ Error *err = NULL; @@ -74,20 +99,14 @@ visit_start_struct(m, (void **)obj, "%(name)s", name, sizeof(%(name)s), &err); ret += mcgen(''' if (!err) { if (!obj || *obj) { -''') - push_indent() - push_indent() - - ret += generate_visit_struct_fields(field_prefix, members) - pop_indent() - ret += mcgen(''' - error_propagate(errp, err); - err = NULL; -} -''') + visit_type_%(name)s_fields(m, obj, &err); + error_propagate(errp, err); + err = NULL; + } +''', + name=full_name) pop_indent() - pop_indent() ret += mcgen(''' /* Always call end_struct if start_struct succeeded. */ visit_end_struct(m, &err); @@ -98,7 +117,9 @@ if (!err) { return ret def generate_visit_struct(name, members): - ret = mcgen(''' + ret = generate_visit_struct_fields(name, "", members) + + ret += mcgen(''' void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **errp) { @@ -157,9 +178,17 @@ def generate_visit_union(expr): members = expr['data'] base = expr.get('base') + discriminator = expr.get('discriminator') ret = generate_visit_enum('%sKind' % name, members.keys()) + if base: + base_fields = find_struct(base)['data'] + if discriminator: + base_fields = base_fields.copy() + del base_fields[discriminator] + ret += generate_visit_struct_fields(name, "", base_fields) + ret += mcgen(''' void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **errp) @@ -179,23 +208,34 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error ** push_indent() if base: - struct = find_struct(base) - push_indent() - ret += generate_visit_struct_fields("", struct['data']) - pop_indent() + ret += mcgen(''' + visit_type_%(name)s_fields(m, obj, &err); +''', + name=name) pop_indent() ret += mcgen(''' - visit_type_%(name)sKind(m, &(*obj)->kind, "type", &err); + visit_type_%(name)sKind(m, &(*obj)->kind, "%(type)s", &err); if (!err) { switch ((*obj)->kind) { ''', - name=name) + name=name, type="type" if not discriminator else discriminator) for key in members: + if not discriminator: + fmt = 'visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, "data", &err);' + else: + fmt = '''visit_start_implicit_struct(m, (void**) &(*obj)->%(c_name)s, sizeof(%(c_type)s), &err); + if (!err) { + visit_type_%(c_type)s_fields(m, &(*obj)->%(c_name)s, &err); + error_propagate(errp, err); + err = NULL; + visit_end_implicit_struct(m, &err); + }''' + ret += mcgen(''' case %(abbrev)s_KIND_%(enum)s: - visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, "data", &err); + ''' + fmt + ''' break; ''', abbrev = de_camel_case(name).upper(),