yeahuh / rpms / qemu-kvm

Forked from rpms/qemu-kvm 2 years ago
Clone

Blame SOURCES/kvm-qapi-Flat-unions-with-arbitrary-discriminator.patch

218e99
From e25370368e98e6d8766e50b7f13e3543e1c3ef9b Mon Sep 17 00:00:00 2001
218e99
From: Kevin Wolf <kwolf@redhat.com>
218e99
Date: Mon, 9 Sep 2013 14:28:12 +0200
218e99
Subject: [PATCH 21/38] qapi: Flat unions with arbitrary discriminator
218e99
218e99
RH-Author: Kevin Wolf <kwolf@redhat.com>
218e99
Message-id: <1378736903-18489-22-git-send-email-kwolf@redhat.com>
218e99
Patchwork-id: 54208
218e99
O-Subject: [RHEL-7.0 qemu-kvm PATCH 21/32] qapi: Flat unions with arbitrary discriminator
218e99
Bugzilla: 1005818
218e99
RH-Acked-by: Fam Zheng <famz@redhat.com>
218e99
RH-Acked-by: Max Reitz <mreitz@redhat.com>
218e99
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
218e99
218e99
Bugzilla: 1005818
218e99
218e99
Instead of the rather verbose syntax that distinguishes base and
218e99
subclass fields...
218e99
218e99
  { "type": "file",
218e99
    "read-only": true,
218e99
    "data": {
218e99
        "filename": "test"
218e99
    } }
218e99
218e99
...we can now have both in the same namespace, allowing a more direct
218e99
mapping of the command line, and moving fields between the common base
218e99
and subclasses without breaking the API:
218e99
218e99
  { "driver": "file",
218e99
    "read-only": true,
218e99
    "filename": "test" }
218e99
218e99
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
218e99
Reviewed-by: Eric Blake <eblake@redhat.com>
218e99
(cherry picked from commit 50f2bdc75c5ee00617ad874c9ceac2cea660aa1e)
218e99
218e99
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
218e99
---
218e99
 docs/qapi-code-gen.txt | 22 ++++++++++++
218e99
 scripts/qapi-types.py  | 11 ++++--
218e99
 scripts/qapi-visit.py  | 90 +++++++++++++++++++++++++++++++++++++-------------
218e99
 3 files changed, 98 insertions(+), 25 deletions(-)
218e99
218e99
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
218e99
---
218e99
 docs/qapi-code-gen.txt |   22 ++++++++++++
218e99
 scripts/qapi-types.py  |   11 +++++-
218e99
 scripts/qapi-visit.py  |   90 +++++++++++++++++++++++++++++++++++------------
218e99
 3 files changed, 98 insertions(+), 25 deletions(-)
218e99
218e99
diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt
218e99
index f6f8d33..11f19cf 100644
218e99
--- a/docs/qapi-code-gen.txt
218e99
+++ b/docs/qapi-code-gen.txt
218e99
@@ -103,6 +103,28 @@ And it looks like this on the wire:
218e99
    "data" : { "backing-file": "/some/place/my-image",
218e99
               "lazy-refcounts": true } }
218e99
 
218e99
+
218e99
+Flat union types avoid the nesting on the wire. They are used whenever a
218e99
+specific field of the base type is declared as the discriminator ('type' is
218e99
+then no longer generated). The discriminator must always be a string field.
218e99
+The above example can then be modified as follows:
218e99
+
218e99
+ { 'type': 'BlockdevCommonOptions',
218e99
+   'data': { 'driver': 'str', 'readonly': 'bool' } }
218e99
+ { 'union': 'BlockdevOptions',
218e99
+   'base': 'BlockdevCommonOptions',
218e99
+   'discriminator': 'driver',
218e99
+   'data': { 'raw': 'RawOptions',
218e99
+             'qcow2': 'Qcow2Options' } }
218e99
+
218e99
+Resulting in this JSON object:
218e99
+
218e99
+ { "driver": "qcow2",
218e99
+   "readonly": false,
218e99
+   "backing-file": "/some/place/my-image",
218e99
+   "lazy-refcounts": true }
218e99
+
218e99
+
218e99
 === Commands ===
218e99
 
218e99
 Commands are defined by using a list containing three members.  The first
218e99
diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
218e99
index c0684a7..f139bfe 100644
218e99
--- a/scripts/qapi-types.py
218e99
+++ b/scripts/qapi-types.py
218e99
@@ -135,7 +135,9 @@ def generate_union(expr):
218e99
 
218e99
     name = expr['union']
218e99
     typeinfo = expr['data']
218e99
+
218e99
     base = expr.get('base')
218e99
+    discriminator = expr.get('discriminator')
218e99
 
218e99
     ret = mcgen('''
218e99
 struct %(name)s
218e99
@@ -158,8 +160,13 @@ struct %(name)s
218e99
 ''')
218e99
 
218e99
     if base:
218e99
-        struct = find_struct(base)
218e99
-        ret += generate_struct_fields(struct['data'])
218e99
+        base_fields = find_struct(base)['data']
218e99
+        if discriminator:
218e99
+            base_fields = base_fields.copy()
218e99
+            del base_fields[discriminator]
218e99
+        ret += generate_struct_fields(base_fields)
218e99
+    else:
218e99
+        assert not discriminator
218e99
 
218e99
     ret += mcgen('''
218e99
 };
218e99
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
218e99
index be56ba4..b1c1ad6 100644
218e99
--- a/scripts/qapi-visit.py
218e99
+++ b/scripts/qapi-visit.py
218e99
@@ -17,8 +17,30 @@ import os
218e99
 import getopt
218e99
 import errno
218e99
 
218e99
-def generate_visit_struct_fields(field_prefix, members):
218e99
+def generate_visit_struct_fields(name, field_prefix, fn_prefix, members):
218e99
+    substructs = []
218e99
     ret = ''
218e99
+    full_name = name if not fn_prefix else "%s_%s" % (name, fn_prefix)
218e99
+
218e99
+    for argname, argentry, optional, structured in parse_args(members):
218e99
+        if structured:
218e99
+            if not fn_prefix:
218e99
+                nested_fn_prefix = argname
218e99
+            else:
218e99
+                nested_fn_prefix = "%s_%s" % (fn_prefix, argname)
218e99
+
218e99
+            nested_field_prefix = "%s%s." % (field_prefix, argname)
218e99
+            ret += generate_visit_struct_fields(name, nested_field_prefix,
218e99
+                                                nested_fn_prefix, argentry)
218e99
+
218e99
+    ret += mcgen('''
218e99
+
218e99
+static void visit_type_%(full_name)s_fields(Visitor *m, %(name)s ** obj, Error **errp)
218e99
+{
218e99
+    Error *err = NULL;
218e99
+''',
218e99
+        name=name, full_name=full_name)
218e99
+    push_indent()
218e99
 
218e99
     for argname, argentry, optional, structured in parse_args(members):
218e99
         if optional:
218e99
@@ -31,7 +53,7 @@ if (obj && (*obj)->%(prefix)shas_%(c_name)s) {
218e99
             push_indent()
218e99
 
218e99
         if structured:
218e99
-            ret += generate_visit_struct_body(field_prefix + argname, argname, argentry)
218e99
+            ret += generate_visit_struct_body(full_name, argname, argentry)
218e99
         else:
218e99
             ret += mcgen('''
218e99
 visit_type_%(type)s(m, obj ? &(*obj)->%(c_prefix)s%(c_name)s : NULL, "%(name)s", &err;;
218e99
@@ -47,6 +69,12 @@ visit_type_%(type)s(m, obj ? &(*obj)->%(c_prefix)s%(c_name)s : NULL, "%(name)s",
218e99
 visit_end_optional(m, &err;;
218e99
 ''')
218e99
 
218e99
+    pop_indent()
218e99
+    ret += mcgen('''
218e99
+
218e99
+    error_propagate(errp, err);
218e99
+}
218e99
+''')
218e99
     return ret
218e99
 
218e99
 
218e99
@@ -56,8 +84,9 @@ if (!error_is_set(errp)) {
218e99
 ''')
218e99
     push_indent()
218e99
 
218e99
+    full_name = name if not field_prefix else "%s_%s" % (field_prefix, name)
218e99
+
218e99
     if len(field_prefix):
218e99
-        field_prefix = field_prefix + "."
218e99
         ret += mcgen('''
218e99
 Error **errp = &err; /* from outer scope */
218e99
 Error *err = NULL;
218e99
@@ -74,20 +103,14 @@ visit_start_struct(m, (void **)obj, "%(name)s", name, sizeof(%(name)s), &err;;
218e99
     ret += mcgen('''
218e99
 if (!err) {
218e99
     if (!obj || *obj) {
218e99
-''')
218e99
-    push_indent()
218e99
-    push_indent()
218e99
-
218e99
-    ret += generate_visit_struct_fields(field_prefix, members)
218e99
-    pop_indent()
218e99
-    ret += mcgen('''
218e99
-    error_propagate(errp, err);
218e99
-    err = NULL;
218e99
-}
218e99
-''')
218e99
+        visit_type_%(name)s_fields(m, obj, &err;;
218e99
+        error_propagate(errp, err);
218e99
+        err = NULL;
218e99
+    }
218e99
+''',
218e99
+        name=full_name)
218e99
 
218e99
     pop_indent()
218e99
-    pop_indent()
218e99
     ret += mcgen('''
218e99
         /* Always call end_struct if start_struct succeeded.  */
218e99
         visit_end_struct(m, &err;;
218e99
@@ -98,7 +121,9 @@ if (!err) {
218e99
     return ret
218e99
 
218e99
 def generate_visit_struct(name, members):
218e99
-    ret = mcgen('''
218e99
+    ret = generate_visit_struct_fields(name, "", "", members)
218e99
+
218e99
+    ret += mcgen('''
218e99
 
218e99
 void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **errp)
218e99
 {
218e99
@@ -157,9 +182,17 @@ def generate_visit_union(expr):
218e99
     members = expr['data']
218e99
 
218e99
     base = expr.get('base')
218e99
+    discriminator = expr.get('discriminator')
218e99
 
218e99
     ret = generate_visit_enum('%sKind' % name, members.keys())
218e99
 
218e99
+    if base:
218e99
+        base_fields = find_struct(base)['data']
218e99
+        if discriminator:
218e99
+            base_fields = base_fields.copy()
218e99
+            del base_fields[discriminator]
218e99
+        ret += generate_visit_struct_fields(name, "", "", base_fields)
218e99
+
218e99
     ret += mcgen('''
218e99
 
218e99
 void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **errp)
218e99
@@ -179,23 +212,34 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error **
218e99
     push_indent()
218e99
 
218e99
     if base:
218e99
-        struct = find_struct(base)
218e99
-        push_indent()
218e99
-        ret += generate_visit_struct_fields("", struct['data'])
218e99
-        pop_indent()
218e99
+        ret += mcgen('''
218e99
+    visit_type_%(name)s_fields(m, obj, &err;;
218e99
+''',
218e99
+            name=name)
218e99
 
218e99
     pop_indent()
218e99
     ret += mcgen('''
218e99
-        visit_type_%(name)sKind(m, &(*obj)->kind, "type", &err;;
218e99
+        visit_type_%(name)sKind(m, &(*obj)->kind, "%(type)s", &err;;
218e99
         if (!err) {
218e99
             switch ((*obj)->kind) {
218e99
 ''',
218e99
-                 name=name)
218e99
+                 name=name, type="type" if not discriminator else discriminator)
218e99
 
218e99
     for key in members:
218e99
+        if not discriminator:
218e99
+            fmt = 'visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, "data", &err;;'
218e99
+        else:
218e99
+            fmt = '''visit_start_implicit_struct(m, (void**) &(*obj)->%(c_name)s, sizeof(%(c_type)s), &err;;
218e99
+                if (!err) {
218e99
+                    visit_type_%(c_type)s_fields(m, &(*obj)->%(c_name)s, &err;;
218e99
+                    error_propagate(errp, err);
218e99
+                    err = NULL;
218e99
+                    visit_end_implicit_struct(m, &err;;
218e99
+                }'''
218e99
+
218e99
         ret += mcgen('''
218e99
             case %(abbrev)s_KIND_%(enum)s:
218e99
-                visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, "data", &err;;
218e99
+                ''' + fmt + '''
218e99
                 break;
218e99
 ''',
218e99
                 abbrev = de_camel_case(name).upper(),
218e99
-- 
218e99
1.7.1
218e99