Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 410 insertions, 0 deletions

diff --git a/scripts/qapi/visit.py b/scripts/qapi/visit.py
new file mode 100644
index 000000000..e13bbe429
--- /dev/null
+++ b/scripts/qapi/visit.py
@@ -0,0 +1,410 @@
+"""
+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 typing import List, Optional
+
+from .common import (
+    c_enum_const,
+    c_name,
+    indent,
+    mcgen,
+)
+from .gen import QAPISchemaModularCVisitor, gen_special_features, ifcontext
+from .schema import (
+    QAPISchema,
+    QAPISchemaEnumMember,
+    QAPISchemaEnumType,
+    QAPISchemaFeature,
+    QAPISchemaIfCond,
+    QAPISchemaObjectType,
+    QAPISchemaObjectTypeMember,
+    QAPISchemaType,
+    QAPISchemaVariants,
+)
+from .source import QAPISourceInfo
+
+
+def gen_visit_decl(name: str, scalar: bool = False) -> str:
+    c_type = c_name(name) + ' *'
+    if not scalar:
+        c_type += '*'
+    return mcgen('''
+
+bool 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: str) -> str:
+    return mcgen('''
+
+bool 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: str,
+                             base: Optional[QAPISchemaObjectType],
+                             members: List[QAPISchemaObjectTypeMember],
+                             variants: Optional[QAPISchemaVariants]) -> str:
+    ret = mcgen('''
+
+bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
+{
+''',
+                c_name=c_name(name))
+
+    if base:
+        ret += mcgen('''
+    if (!visit_type_%(c_type)s_members(v, (%(c_type)s *)obj, errp)) {
+        return false;
+    }
+''',
+                     c_type=base.c_name())
+
+    for memb in members:
+        ret += memb.ifcond.gen_if()
+        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))
+            indent.increase()
+        special_features = gen_special_features(memb.features)
+        if special_features != '0':
+            ret += mcgen('''
+    if (visit_policy_reject(v, "%(name)s", %(special_features)s, errp)) {
+        return false;
+    }
+    if (!visit_policy_skip(v, "%(name)s", %(special_features)s)) {
+''',
+                         name=memb.name, special_features=special_features)
+            indent.increase()
+        ret += mcgen('''
+    if (!visit_type_%(c_type)s(v, "%(name)s", &obj->%(c_name)s, errp)) {
+        return false;
+    }
+''',
+                     c_type=memb.type.c_name(), name=memb.name,
+                     c_name=c_name(memb.name))
+        if special_features != '0':
+            indent.decrease()
+            ret += mcgen('''
+    }
+''')
+        if memb.optional:
+            indent.decrease()
+            ret += mcgen('''
+    }
+''')
+        ret += memb.ifcond.gen_endif()
+
+    if variants:
+        tag_member = variants.tag_member
+        assert isinstance(tag_member.type, QAPISchemaEnumType)
+
+        ret += mcgen('''
+    switch (obj->%(c_name)s) {
+''',
+                     c_name=c_name(tag_member.name))
+
+        for var in variants.variants:
+            case_str = c_enum_const(tag_member.type.name, var.name,
+                                    tag_member.type.prefix)
+            ret += var.ifcond.gen_if()
+            if var.type.name == 'q_empty':
+                # valid variant and nothing to do
+                ret += mcgen('''
+    case %(case)s:
+        break;
+''',
+                             case=case_str)
+            else:
+                ret += mcgen('''
+    case %(case)s:
+        return visit_type_%(c_type)s_members(v, &obj->u.%(c_name)s, errp);
+''',
+                             case=case_str,
+                             c_type=var.type.c_name(), c_name=c_name(var.name))
+
+            ret += var.ifcond.gen_endif()
+        ret += mcgen('''
+    default:
+        abort();
+    }
+''')
+
+    ret += mcgen('''
+    return true;
+}
+''')
+    return ret
+
+
+def gen_visit_list(name: str, element_type: QAPISchemaType) -> str:
+    return mcgen('''
+
+bool visit_type_%(c_name)s(Visitor *v, const char *name,
+                 %(c_name)s **obj, Error **errp)
+{
+    bool ok = false;
+    %(c_name)s *tail;
+    size_t size = sizeof(**obj);
+
+    if (!visit_start_list(v, name, (GenericList **)obj, size, errp)) {
+        return false;
+    }
+
+    for (tail = *obj; tail;
+         tail = (%(c_name)s *)visit_next_list(v, (GenericList *)tail, size)) {
+        if (!visit_type_%(c_elt_type)s(v, NULL, &tail->value, errp)) {
+            goto out_obj;
+        }
+    }
+
+    ok = visit_check_list(v, errp);
+out_obj:
+    visit_end_list(v, (void **)obj);
+    if (!ok && visit_is_input(v)) {
+        qapi_free_%(c_name)s(*obj);
+        *obj = NULL;
+    }
+    return ok;
+}
+''',
+                 c_name=c_name(name), c_elt_type=element_type.c_name())
+
+
+def gen_visit_enum(name: str) -> str:
+    return mcgen('''
+
+bool visit_type_%(c_name)s(Visitor *v, const char *name,
+                 %(c_name)s *obj, Error **errp)
+{
+    int value = *obj;
+    bool ok = visit_type_enum(v, name, &value, &%(c_name)s_lookup, errp);
+    *obj = value;
+    return ok;
+}
+''',
+                 c_name=c_name(name))
+
+
+def gen_visit_alternate(name: str, variants: QAPISchemaVariants) -> str:
+    ret = mcgen('''
+
+bool visit_type_%(c_name)s(Visitor *v, const char *name,
+                 %(c_name)s **obj, Error **errp)
+{
+    bool ok = false;
+
+    if (!visit_start_alternate(v, name, (GenericAlternate **)obj,
+                               sizeof(**obj), errp)) {
+        return false;
+    }
+    if (!*obj) {
+        /* incomplete */
+        assert(visit_is_dealloc(v));
+        ok = true;
+        goto out_obj;
+    }
+    switch ((*obj)->type) {
+''',
+                c_name=c_name(name))
+
+    for var in variants.variants:
+        ret += var.ifcond.gen_if()
+        ret += mcgen('''
+    case %(case)s:
+''',
+                     case=var.type.alternate_qtype())
+        if isinstance(var.type, QAPISchemaObjectType):
+            ret += mcgen('''
+        if (!visit_start_struct(v, name, NULL, 0, errp)) {
+            break;
+        }
+        if (visit_type_%(c_type)s_members(v, &(*obj)->u.%(c_name)s, errp)) {
+            ok = visit_check_struct(v, errp);
+        }
+        visit_end_struct(v, NULL);
+''',
+                         c_type=var.type.c_name(),
+                         c_name=c_name(var.name))
+        else:
+            ret += mcgen('''
+        ok = visit_type_%(c_type)s(v, name, &(*obj)->u.%(c_name)s, errp);
+''',
+                         c_type=var.type.c_name(),
+                         c_name=c_name(var.name))
+        ret += mcgen('''
+        break;
+''')
+        ret += var.ifcond.gen_endif()
+
+    ret += mcgen('''
+    case QTYPE_NONE:
+        abort();
+    default:
+        assert(visit_is_input(v));
+        error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                   "%(name)s");
+        /* Avoid passing invalid *obj to qapi_free_%(c_name)s() */
+        g_free(*obj);
+        *obj = NULL;
+    }
+out_obj:
+    visit_end_alternate(v, (void **)obj);
+    if (!ok && visit_is_input(v)) {
+        qapi_free_%(c_name)s(*obj);
+        *obj = NULL;
+    }
+    return ok;
+}
+''',
+                 name=name, c_name=c_name(name))
+
+    return ret
+
+
+def gen_visit_object(name: str) -> str:
+    return mcgen('''
+
+bool visit_type_%(c_name)s(Visitor *v, const char *name,
+                 %(c_name)s **obj, Error **errp)
+{
+    bool ok = false;
+
+    if (!visit_start_struct(v, name, (void **)obj, sizeof(%(c_name)s), errp)) {
+        return false;
+    }
+    if (!*obj) {
+        /* incomplete */
+        assert(visit_is_dealloc(v));
+        ok = true;
+        goto out_obj;
+    }
+    if (!visit_type_%(c_name)s_members(v, *obj, errp)) {
+        goto out_obj;
+    }
+    ok = visit_check_struct(v, errp);
+out_obj:
+    visit_end_struct(v, (void **)obj);
+    if (!ok && visit_is_input(v)) {
+        qapi_free_%(c_name)s(*obj);
+        *obj = NULL;
+    }
+    return ok;
+}
+''',
+                 c_name=c_name(name))
+
+
+class QAPISchemaGenVisitVisitor(QAPISchemaModularCVisitor):
+
+    def __init__(self, prefix: str):
+        super().__init__(
+            prefix, 'qapi-visit', ' * Schema-defined QAPI visitors',
+            ' * Built-in QAPI visitors', __doc__)
+
+    def _begin_builtin_module(self) -> None:
+        self._genc.preamble_add(mcgen('''
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qapi/qapi-builtin-visit.h"
+'''))
+        self._genh.preamble_add(mcgen('''
+#include "qapi/visitor.h"
+#include "qapi/qapi-builtin-types.h"
+
+'''))
+
+    def _begin_user_module(self, name: str) -> None:
+        types = self._module_basename('qapi-types', name)
+        visit = self._module_basename('qapi-visit', name)
+        self._genc.preamble_add(mcgen('''
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qerror.h"
+#include "%(visit)s.h"
+''',
+                                      visit=visit))
+        self._genh.preamble_add(mcgen('''
+#include "qapi/qapi-builtin-visit.h"
+#include "%(types)s.h"
+
+''',
+                                      types=types))
+
+    def visit_enum_type(self,
+                        name: str,
+                        info: Optional[QAPISourceInfo],
+                        ifcond: QAPISchemaIfCond,
+                        features: List[QAPISchemaFeature],
+                        members: List[QAPISchemaEnumMember],
+                        prefix: Optional[str]) -> None:
+        with ifcontext(ifcond, self._genh, self._genc):
+            self._genh.add(gen_visit_decl(name, scalar=True))
+            self._genc.add(gen_visit_enum(name))
+
+    def visit_array_type(self,
+                         name: str,
+                         info: Optional[QAPISourceInfo],
+                         ifcond: QAPISchemaIfCond,
+                         element_type: QAPISchemaType) -> None:
+        with ifcontext(ifcond, self._genh, self._genc):
+            self._genh.add(gen_visit_decl(name))
+            self._genc.add(gen_visit_list(name, element_type))
+
+    def visit_object_type(self,
+                          name: str,
+                          info: Optional[QAPISourceInfo],
+                          ifcond: QAPISchemaIfCond,
+                          features: List[QAPISchemaFeature],
+                          base: Optional[QAPISchemaObjectType],
+                          members: List[QAPISchemaObjectTypeMember],
+                          variants: Optional[QAPISchemaVariants]) -> None:
+        # Nothing to do for the special empty builtin
+        if name == 'q_empty':
+            return
+        with ifcontext(ifcond, self._genh, self._genc):
+            self._genh.add(gen_visit_members_decl(name))
+            self._genc.add(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._genh.add(gen_visit_decl(name))
+                self._genc.add(gen_visit_object(name))
+
+    def visit_alternate_type(self,
+                             name: str,
+                             info: Optional[QAPISourceInfo],
+                             ifcond: QAPISchemaIfCond,
+                             features: List[QAPISchemaFeature],
+                             variants: QAPISchemaVariants) -> None:
+        with ifcontext(ifcond, self._genh, self._genc):
+            self._genh.add(gen_visit_decl(name))
+            self._genc.add(gen_visit_alternate(name, variants))
+
+
+def gen_visit(schema: QAPISchema,
+              output_dir: str,
+              prefix: str,
+              opt_builtins: bool) -> None:
+    vis = QAPISchemaGenVisitVisitor(prefix)
+    schema.visit(vis)
+    vis.write(output_dir, opt_builtins)