This patch handles QAPI event types and generates data structures in Go that handles it.
We also define a Event interface and two helper functions MarshalEvent and UnmarshalEvent. At the moment of this writing, this patch generates 51 structures (50 events) Example: qapi: | { 'event': 'MEMORY_DEVICE_SIZE_CHANGE', | 'data': { '*id': 'str', 'size': 'size', 'qom-path' : 'str'} } go: | type MemoryDeviceSizeChangeEvent struct { | EventTimestamp Timestamp `json:"-"` | Id *string `json:"id,omitempty"` | Size uint64 `json:"size"` | QomPath string `json:"qom-path"` | } usage: | input := `{"event":"MEMORY_DEVICE_SIZE_CHANGE",` + | `"timestamp":{"seconds":1588168529,"microseconds":201316},` + | `"data":{"id":"vm0","size":1073741824,"qom-path":"/machine/unattached/device[2]"}}` | e, err := UnmarshalEvent([]byte(input) | if err != nil { | panic(err) | } | if e.GetName() == `MEMORY_DEVICE_SIZE_CHANGE` { | m := e.(*MemoryDeviceSizeChangeEvent) | // m.QomPath == "/machine/unattached/device[2]" | } Signed-off-by: Victor Toso <victort...@redhat.com> --- scripts/qapi/golang.py | 120 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 118 insertions(+), 2 deletions(-) diff --git a/scripts/qapi/golang.py b/scripts/qapi/golang.py index 6c6a5cea97..b2e08cebdf 100644 --- a/scripts/qapi/golang.py +++ b/scripts/qapi/golang.py @@ -28,7 +28,66 @@ ) from .source import QAPISourceInfo +# Only variable is @unm_cases to handle +# all events's names and associated types. +TEMPLATE_EVENT = ''' +type Timestamp struct {{ + Seconds int64 `json:"seconds"` + Microseconds int64 `json:"microseconds"` +}} + +type Event interface {{ + GetName() string + GetTimestamp() Timestamp +}} +func MarshalEvent(e Event) ([]byte, error) {{ + baseStruct := struct {{ + Name string `json:"event"` + EventTimestamp Timestamp `json:"timestamp"` + }}{{ + Name: e.GetName(), + EventTimestamp: e.GetTimestamp(), + }} + base, err := json.Marshal(baseStruct) + if err != nil {{ + return []byte{{}}, err + }} + + dataStruct := struct {{ + Payload Event `json:"data"` + }}{{ + Payload: e, + }} + data, err := json.Marshal(dataStruct) + if err != nil {{ + return []byte{{}}, err + }} + + if len(data) == len(`{{"data":{{}}}}`) {{ + return base, nil + }} + + // Combines Event's base and data in a single JSON object + result := fmt.Sprintf("%s,%s", base[:len(base)-1], data[1:]) + return []byte(result), nil +}} + +func UnmarshalEvent(data []byte) (Event, error) {{ + base := struct {{ + Name string `json:"event"` + EventTimestamp Timestamp `json:"timestamp"` + }}{{}} + if err := json.Unmarshal(data, &base); err != nil {{ + return nil, errors.New(fmt.Sprintf("Failed to decode event: %s", string(data))) + }} + + switch base.Name {{ + {unm_cases} + }} + return nil, errors.New("Failed to recognize event") +}} +''' TEMPLATE_HELPER = ''' // Alias for go version lower than 1.18 type Any = interface{} @@ -53,10 +112,12 @@ class QAPISchemaGenGolangVisitor(QAPISchemaVisitor): def __init__(self, prefix: str): super().__init__() - self.target = {name: "" for name in ["alternate", "enum", "helper", "struct", + self.target = {name: "" for name in ["alternate", "enum", + "event", "helper", "struct", "union"]} self.objects_seen = {} self.schema = None + self.events = {} self.golang_package_name = "qapi" def visit_begin(self, schema): @@ -71,6 +132,24 @@ def visit_begin(self, schema): def visit_end(self): self.schema = None + unm_cases = "" + for name in sorted(self.events): + case_type = self.events[name] + unm_cases += f''' + case "{name}": + event := struct {{ + Data {case_type} `json:"data"` + }}{{}} + + if err := json.Unmarshal(data, &event); err != nil {{ + return nil, errors.New(fmt.Sprintf("Failed to unmarshal: %s", string(data))) + }} + event.Data.EventTimestamp = base.EventTimestamp + return &event.Data, nil +''' + self.target["event"] += TEMPLATE_EVENT.format(unm_cases=unm_cases) + + def visit_object_type(self: QAPISchemaGenGolangVisitor, name: str, info: Optional[QAPISourceInfo], @@ -232,7 +311,37 @@ def visit_command(self, pass def visit_event(self, name, info, ifcond, features, arg_type, boxed): - pass + assert name == info.defn_name + type_name = qapi_to_go_type_name(name, info.defn_meta) + self.events[name] = type_name + + self_contained = True + if arg_type and arg_type.name.startswith("q_obj"): + self_contained = False + + content = "" + if self_contained: + content = generate_struct_type(type_name, '''EventTimestamp Timestamp `json:"-"`''') + else: + assert isinstance(arg_type, QAPISchemaObjectType) + content = qapi_to_golang_struct(name, + arg_type.info, + arg_type.ifcond, + arg_type.features, + arg_type.base, + arg_type.members, + arg_type.variants) + + methods = f''' +func (s *{type_name}) GetName() string {{ + return "{name}" +}} + +func (s *{type_name}) GetTimestamp() Timestamp {{ + return s.EventTimestamp +}} +''' + self.target["event"] += content + methods def write(self, output_dir: str) -> None: for module_name, content in self.target.items(): @@ -274,6 +383,8 @@ def qapi_to_golang_struct(name: str, type_name = qapi_to_go_type_name(name, info.defn_meta) fields = "" + if info.defn_meta == "event": + fields += '''\tEventTimestamp Timestamp `json:"-"`\n''' if base: base_fields = "" @@ -457,4 +568,9 @@ def qapi_to_go_type_name(name: str, meta: str) -> str: name = name.title() name += ''.join(word.title() for word in words[1:]) + + if meta in ["event"]: + name = name[:-3] if name.endswith("Arg") else name + name += meta.title().replace(" ", "") + return name -- 2.36.1