diff options
Diffstat (limited to 'docs/qapi-code-gen.txt')
| -rw-r--r-- | docs/qapi-code-gen.txt | 100 |
1 files changed, 80 insertions, 20 deletions
diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt index a6197a9133..8313ba6af8 100644 --- a/docs/qapi-code-gen.txt +++ b/docs/qapi-code-gen.txt @@ -1,10 +1,5 @@ = How to use the QAPI code generator = -* Note: as of this writing, QMP does not use QAPI. Eventually QMP -commands will be converted to use QAPI internally. The following -information describes QMP/QAPI as it will exist after the -conversion. - QAPI is a native C API within QEMU which provides management-level functionality to internal/external users. For external users/processes, this interface is made available by a JSON-based @@ -19,7 +14,7 @@ marshaling/dispatch code for the guest agent server running in the guest. This document will describe how the schemas, scripts, and resulting -code is used. +code are used. == QMP/Guest agent schema == @@ -234,6 +229,7 @@ Resulting in this JSON object: "data": { "b": "test string" }, "timestamp": { "seconds": 1267020223, "microseconds": 435656 } } + == Code generation == Schemas are fed into 3 scripts to generate all the code/files that, paired @@ -256,6 +252,8 @@ command which takes that type as a parameter and returns the same type: 'data': {'arg1': 'UserDefOne'}, 'returns': 'UserDefOne' } + { 'event': 'MY_EVENT' } + === scripts/qapi-types.py === Used to generate the C types defined by a schema. The following files are @@ -277,7 +275,7 @@ Example: $ cat qapi-generated/example-qapi-types.c [Uninteresting stuff omitted...] - void qapi_free_UserDefOneList(UserDefOneList * obj) + void qapi_free_UserDefOneList(UserDefOneList *obj) { QapiDeallocVisitor *md; Visitor *v; @@ -292,7 +290,7 @@ Example: qapi_dealloc_visitor_cleanup(md); } - void qapi_free_UserDefOne(UserDefOne * obj) + void qapi_free_UserDefOne(UserDefOne *obj) { QapiDeallocVisitor *md; Visitor *v; @@ -331,11 +329,11 @@ Example: struct UserDefOne { int64_t integer; - char * string; + char *string; }; - void qapi_free_UserDefOneList(UserDefOneList * obj); - void qapi_free_UserDefOne(UserDefOne * obj); + void qapi_free_UserDefOneList(UserDefOneList *obj); + void qapi_free_UserDefOne(UserDefOne *obj); #endif @@ -364,7 +362,7 @@ Example: $ cat qapi-generated/example-qapi-visit.c [Uninteresting stuff omitted...] - static void visit_type_UserDefOne_fields(Visitor *m, UserDefOne ** obj, Error **errp) + static void visit_type_UserDefOne_fields(Visitor *m, UserDefOne **obj, Error **errp) { Error *err = NULL; visit_type_int(m, &(*obj)->integer, "integer", &err); @@ -380,7 +378,7 @@ Example: error_propagate(errp, err); } - void visit_type_UserDefOne(Visitor *m, UserDefOne ** obj, const char *name, Error **errp) + void visit_type_UserDefOne(Visitor *m, UserDefOne **obj, const char *name, Error **errp) { Error *err = NULL; @@ -394,7 +392,7 @@ Example: error_propagate(errp, err); } - void visit_type_UserDefOneList(Visitor *m, UserDefOneList ** obj, const char *name, Error **errp) + void visit_type_UserDefOneList(Visitor *m, UserDefOneList **obj, const char *name, Error **errp) { Error *err = NULL; GenericList *i, **prev; @@ -427,8 +425,8 @@ Example: [Visitors for builtin types omitted...] - void visit_type_UserDefOne(Visitor *m, UserDefOne ** obj, const char *name, Error **errp); - void visit_type_UserDefOneList(Visitor *m, UserDefOneList ** obj, const char *name, Error **errp); + void visit_type_UserDefOne(Visitor *m, UserDefOne **obj, const char *name, Error **errp); + void visit_type_UserDefOneList(Visitor *m, UserDefOneList **obj, const char *name, Error **errp); #endif @@ -451,10 +449,12 @@ $(prefix)qmp-commands.h: Function prototypes for the QMP commands Example: + $ python scripts/qapi-commands.py --output-dir="qapi-generated" + --prefix="example-" --input-file=example-schema.json $ cat qapi-generated/example-qmp-marshal.c [Uninteresting stuff omitted...] - static void qmp_marshal_output_my_command(UserDefOne * ret_in, QObject **ret_out, Error **errp) + static void qmp_marshal_output_my_command(UserDefOne *ret_in, QObject **ret_out, Error **errp) { Error *local_err = NULL; QmpOutputVisitor *mo = qmp_output_visitor_new(); @@ -480,11 +480,11 @@ Example: static void qmp_marshal_input_my_command(QDict *args, QObject **ret, Error **errp) { Error *local_err = NULL; - UserDefOne * retval = NULL; + UserDefOne *retval = NULL; QmpInputVisitor *mi = qmp_input_visitor_new_strict(QOBJECT(args)); QapiDeallocVisitor *md; Visitor *v; - UserDefOne * arg1 = NULL; + UserDefOne *arg1 = NULL; v = qmp_input_get_visitor(mi); visit_type_UserDefOne(v, &arg1, "arg1", &local_err); @@ -525,6 +525,66 @@ Example: #include "qapi/qmp/qdict.h" #include "qapi/error.h" - UserDefOne * qmp_my_command(UserDefOne * arg1, Error **errp); + UserDefOne *qmp_my_command(UserDefOne *arg1, Error **errp); + + #endif + +=== scripts/qapi-event.py === + +Used to generate the event-related C code defined by a schema. The +following files are created: + +$(prefix)qapi-event.h - Function prototypes for each event type, plus an + enumeration of all event names +$(prefix)qapi-event.c - Implementation of functions to send an event + +Example: + + $ python scripts/qapi-event.py --output-dir="qapi-generated" + --prefix="example-" --input-file=example-schema.json + $ cat qapi-generated/example-qapi-event.c +[Uninteresting stuff omitted...] + + void qapi_event_send_my_event(Error **errp) + { + QDict *qmp; + Error *local_err = NULL; + QMPEventFuncEmit emit; + emit = qmp_event_get_func_emit(); + if (!emit) { + return; + } + + qmp = qmp_event_build_dict("MY_EVENT"); + + emit(EXAMPLE_QAPI_EVENT_MY_EVENT, qmp, &local_err); + + error_propagate(errp, local_err); + QDECREF(qmp); + } + + const char *EXAMPLE_QAPIEvent_lookup[] = { + "MY_EVENT", + NULL, + }; + $ cat qapi-generated/example-qapi-event.h +[Uninteresting stuff omitted...] + + #ifndef EXAMPLE_QAPI_EVENT_H + #define EXAMPLE_QAPI_EVENT_H + + #include "qapi/error.h" + #include "qapi/qmp/qdict.h" + #include "example-qapi-types.h" + + + void qapi_event_send_my_event(Error **errp); + + extern const char *EXAMPLE_QAPIEvent_lookup[]; + typedef enum EXAMPLE_QAPIEvent + { + EXAMPLE_QAPI_EVENT_MY_EVENT = 0, + EXAMPLE_QAPI_EVENT_MAX = 1, + } EXAMPLE_QAPIEvent; #endif |