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, 252 insertions, 0 deletions

diff --git a/scripts/qapi/events.py b/scripts/qapi/events.py
new file mode 100644
index 000000000..27b44c49f
--- /dev/null
+++ b/scripts/qapi/events.py
@@ -0,0 +1,252 @@
+"""
+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 typing import List, Optional
+
+from .common import c_enum_const, c_name, mcgen
+from .gen import QAPISchemaModularCVisitor, build_params, ifcontext
+from .schema import (
+    QAPISchema,
+    QAPISchemaEnumMember,
+    QAPISchemaFeature,
+    QAPISchemaIfCond,
+    QAPISchemaObjectType,
+)
+from .source import QAPISourceInfo
+from .types import gen_enum, gen_enum_lookup
+
+
+def build_event_send_proto(name: str,
+                           arg_type: Optional[QAPISchemaObjectType],
+                           boxed: bool) -> str:
+    return 'void qapi_event_send_%(c_name)s(%(param)s)' % {
+        'c_name': c_name(name.lower()),
+        'param': build_params(arg_type, boxed)}
+
+
+def gen_event_send_decl(name: str,
+                        arg_type: Optional[QAPISchemaObjectType],
+                        boxed: bool) -> str:
+    return mcgen('''
+
+%(proto)s;
+''',
+                 proto=build_event_send_proto(name, arg_type, boxed))
+
+
+def gen_param_var(typ: QAPISchemaObjectType) -> str:
+    """
+    Generate a struct variable holding the event parameters.
+
+    Initialize it with the function arguments defined in `gen_event_send`.
+    """
+    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: str,
+                   arg_type: Optional[QAPISchemaObjectType],
+                   features: List[QAPISchemaFeature],
+                   boxed: bool,
+                   event_enum_name: str,
+                   event_emit: str) -> str:
+    # 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.
+    have_args = boxed or (arg_type and not arg_type.is_empty())
+
+    ret = mcgen('''
+
+%(proto)s
+{
+    QDict *qmp;
+''',
+                proto=build_event_send_proto(name, arg_type, boxed))
+
+    if have_args:
+        assert arg_type is not None
+        ret += mcgen('''
+    QObject *obj;
+    Visitor *v;
+''')
+        if not boxed:
+            ret += gen_param_var(arg_type)
+
+    for f in features:
+        if f.is_special():
+            ret += mcgen('''
+
+    if (compat_policy.%(feat)s_output == COMPAT_POLICY_OUTPUT_HIDE) {
+        return;
+    }
+''',
+                         feat=f.name)
+
+    ret += mcgen('''
+
+    qmp = qmp_event_build_dict("%(name)s");
+
+''',
+                 name=name)
+
+    if have_args:
+        assert arg_type is not None
+        ret += mcgen('''
+    v = qobject_output_visitor_new_qmp(&obj);
+''')
+        if not arg_type.is_implicit():
+            ret += mcgen('''
+    visit_type_%(c_name)s(v, "%(name)s", &arg, &error_abort);
+''',
+                         name=name, c_name=arg_type.c_name())
+        else:
+            ret += mcgen('''
+
+    visit_start_struct(v, "%(name)s", NULL, 0, &error_abort);
+    visit_type_%(c_name)s_members(v, &param, &error_abort);
+    visit_check_struct(v, &error_abort);
+    visit_end_struct(v, NULL);
+''',
+                         name=name, c_name=arg_type.c_name())
+        ret += mcgen('''
+
+    visit_complete(v, &obj);
+    if (qdict_size(qobject_to(QDict, obj))) {
+        qdict_put_obj(qmp, "data", obj);
+    } else {
+        qobject_unref(obj);
+    }
+''')
+
+    ret += mcgen('''
+    %(event_emit)s(%(c_enum)s, qmp);
+
+''',
+                 event_emit=event_emit,
+                 c_enum=c_enum_const(event_enum_name, name))
+
+    if have_args:
+        ret += mcgen('''
+    visit_free(v);
+''')
+    ret += mcgen('''
+    qobject_unref(qmp);
+}
+''')
+    return ret
+
+
+class QAPISchemaGenEventVisitor(QAPISchemaModularCVisitor):
+
+    def __init__(self, prefix: str):
+        super().__init__(
+            prefix, 'qapi-events',
+            ' * Schema-defined QAPI/QMP events', None, __doc__)
+        self._event_enum_name = c_name(prefix + 'QAPIEvent', protect=False)
+        self._event_enum_members: List[QAPISchemaEnumMember] = []
+        self._event_emit_name = c_name(prefix + 'qapi_event_emit')
+
+    def _begin_user_module(self, name: str) -> None:
+        events = self._module_basename('qapi-events', name)
+        types = self._module_basename('qapi-types', name)
+        visit = self._module_basename('qapi-visit', name)
+        self._genc.add(mcgen('''
+#include "qemu/osdep.h"
+#include "%(prefix)sqapi-emit-events.h"
+#include "%(events)s.h"
+#include "%(visit)s.h"
+#include "qapi/compat-policy.h"
+#include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp-event.h"
+
+''',
+                             events=events, visit=visit,
+                             prefix=self._prefix))
+        self._genh.add(mcgen('''
+#include "qapi/util.h"
+#include "%(types)s.h"
+''',
+                             types=types))
+
+    def visit_end(self) -> None:
+        self._add_module('./emit', ' * QAPI Events emission')
+        self._genc.preamble_add(mcgen('''
+#include "qemu/osdep.h"
+#include "%(prefix)sqapi-emit-events.h"
+''',
+                                      prefix=self._prefix))
+        self._genh.preamble_add(mcgen('''
+#include "qapi/util.h"
+'''))
+        self._genh.add(gen_enum(self._event_enum_name,
+                                self._event_enum_members))
+        self._genc.add(gen_enum_lookup(self._event_enum_name,
+                                       self._event_enum_members))
+        self._genh.add(mcgen('''
+
+void %(event_emit)s(%(event_enum)s event, QDict *qdict);
+''',
+                             event_emit=self._event_emit_name,
+                             event_enum=self._event_enum_name))
+
+    def visit_event(self,
+                    name: str,
+                    info: Optional[QAPISourceInfo],
+                    ifcond: QAPISchemaIfCond,
+                    features: List[QAPISchemaFeature],
+                    arg_type: Optional[QAPISchemaObjectType],
+                    boxed: bool) -> None:
+        with ifcontext(ifcond, self._genh, self._genc):
+            self._genh.add(gen_event_send_decl(name, arg_type, boxed))
+            self._genc.add(gen_event_send(name, arg_type, features, boxed,
+                                          self._event_enum_name,
+                                          self._event_emit_name))
+        # Note: we generate the enum member regardless of @ifcond, to
+        # keep the enumeration usable in target-independent code.
+        self._event_enum_members.append(QAPISchemaEnumMember(name, None))
+
+
+def gen_events(schema: QAPISchema,
+               output_dir: str,
+               prefix: str) -> None:
+    vis = QAPISchemaGenEventVisitor(prefix)
+    schema.visit(vis)
+    vis.write(output_dir)