[Qemu-devel] [PATCH v4 06/20] monitor: use qmp session to parse json feed

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

Use the QmpSession json parser introduced in previous patch to
generalize the handling in both qemu & qemu-ga. Unfortunately, since
the introduction of OOB, it's not as common as it was before that. We
may want to move some of OOB logic in common qmp-dispatch.c/QmpSession
though.

The QEMU monitor has peculiar handling of the stream of commands, for
OOB command processing, which can be solved by overriding the json
emit callback.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 include/qapi/qmp/dispatch.h    |  1 +
 include/qapi/qmp/json-parser.h |  7 ++++---
 monitor.c                      | 16 +++++-----------
 qapi/qmp-dispatch.c            |  4 +++-
 qga/main.c                     |  2 +-
 qobject/json-streamer.c        |  3 +--
 tests/test-qmp-cmds.c          | 11 ++++++-----
 7 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/include/qapi/qmp/dispatch.h b/include/qapi/qmp/dispatch.h
index c84edff7d2..b3ca6c9ff2 100644
--- a/include/qapi/qmp/dispatch.h
+++ b/include/qapi/qmp/dispatch.h
@@ -53,6 +53,7 @@ const QmpCommand *qmp_find_command(const QmpCommandList *cmds,
                                    const char *name);
 void qmp_session_init(QmpSession *session,
                       const QmpCommandList *cmds,
+                      JSONMessageEmit *emit,
                       QmpDispatchReturn *return_cb);
 static inline void
 qmp_session_feed(QmpSession *session, const char *buf, size_t count)
diff --git a/include/qapi/qmp/json-parser.h b/include/qapi/qmp/json-parser.h
index 7345a9bd5c..6f168e8007 100644
--- a/include/qapi/qmp/json-parser.h
+++ b/include/qapi/qmp/json-parser.h
@@ -14,6 +14,8 @@
 #ifndef QAPI_QMP_JSON_PARSER_H
 #define QAPI_QMP_JSON_PARSER_H
 
+typedef void (JSONMessageEmit)(void *opaque, QObject *json, Error *err);
+
 typedef struct JSONLexer {
     int start_state, state;
     GString *token;
@@ -21,7 +23,7 @@ typedef struct JSONLexer {
 } JSONLexer;
 
 typedef struct JSONMessageParser {
-    void (*emit)(void *opaque, QObject *json, Error *err);
+    JSONMessageEmit *emit;
     void *opaque;
     va_list *ap;
     JSONLexer lexer;
@@ -32,8 +34,7 @@ typedef struct JSONMessageParser {
 } JSONMessageParser;
 
 void json_message_parser_init(JSONMessageParser *parser,
-                              void (*emit)(void *opaque, QObject *json,
-                                           Error *err),
+                              JSONMessageEmit *emit,
                               void *opaque, va_list *ap);
 
 void json_message_parser_feed(JSONMessageParser *parser,
diff --git a/monitor.c b/monitor.c
index c23ba76f78..71aad8d1ae 100644
--- a/monitor.c
+++ b/monitor.c
@@ -59,7 +59,6 @@
 #include "qapi/qmp/qnum.h"
 #include "qapi/qmp/qstring.h"
 #include "qapi/qmp/qjson.h"
-#include "qapi/qmp/json-parser.h"
 #include "qapi/qmp/qlist.h"
 #include "qom/object_interfaces.h"
 #include "trace-root.h"
@@ -167,7 +166,6 @@ struct MonFdset {
 };
 
 typedef struct {
-    JSONMessageParser parser;
     /*
      * When a client connects, we're in capabilities negotiation mode.
      * @commands is &qmp_cap_negotiation_commands then.  When command
@@ -730,7 +728,6 @@ static void monitor_data_destroy(Monitor *mon)
     qemu_chr_fe_deinit(&mon->chr, false);
     if (monitor_is_qmp(mon)) {
         qmp_session_destroy(&mon->qmp.session);
-        json_message_parser_destroy(&mon->qmp.parser);
     }
     readline_free(mon->rs);
     qobject_unref(mon->outbuf);
@@ -4216,7 +4213,7 @@ static void monitor_qmp_bh_dispatcher(void *data)
 
 static void handle_qmp_command(void *opaque, QObject *req, Error *err)
 {
-    Monitor *mon = opaque;
+    Monitor *mon = container_of(opaque, Monitor, qmp);
     QObject *id = NULL;
     QDict *qdict;
     QMPRequest *req_obj;
@@ -4278,7 +4275,7 @@ static void monitor_qmp_read(void *opaque, const uint8_t *buf, int size)
 {
     Monitor *mon = opaque;
 
-    json_message_parser_feed(&mon->qmp.parser, (const char *) buf, size);
+    qmp_session_feed(&mon->qmp.session, (const char *) buf, size);
 }
 
 static void monitor_read(void *opaque, const uint8_t *buf, int size)
@@ -4391,7 +4388,9 @@ static void monitor_qmp_event(void *opaque, int event)
     switch (event) {
     case CHR_EVENT_OPENED:
         qmp_session_init(&mon->qmp.session,
-                         &qmp_cap_negotiation_commands, dispatch_return_cb);
+                         &qmp_cap_negotiation_commands,
+                         handle_qmp_command,
+                         dispatch_return_cb);
         monitor_qmp_caps_reset(mon);
         data = qmp_greeting(mon);
         qmp_send_response(mon, data);
@@ -4407,9 +4406,6 @@ static void monitor_qmp_event(void *opaque, int event)
          */
         monitor_qmp_cleanup_queues(mon);
         qmp_session_destroy(&mon->qmp.session);
-        json_message_parser_destroy(&mon->qmp.parser);
-        json_message_parser_init(&mon->qmp.parser, handle_qmp_command,
-                                 mon, NULL);
         mon_refcount--;
         monitor_fdsets_cleanup();
         break;
@@ -4615,8 +4611,6 @@ void monitor_init(Chardev *chr, int flags)
 
     if (monitor_is_qmp(mon)) {
         qemu_chr_fe_set_echo(&mon->chr, true);
-        json_message_parser_init(&mon->qmp.parser, handle_qmp_command,
-                                 mon, NULL);
         if (mon->use_io_thread) {
             /*
              * Make sure the old iowatch is gone.  It's possible when
diff --git a/qapi/qmp-dispatch.c b/qapi/qmp-dispatch.c
index 803ec626cd..f2c376d005 100644
--- a/qapi/qmp-dispatch.c
+++ b/qapi/qmp-dispatch.c
@@ -182,12 +182,14 @@ static void qmp_json_emit(void *opaque, QObject *obj, Error *err)
 
 void qmp_session_init(QmpSession *session,
                       const QmpCommandList *cmds,
+                      JSONMessageEmit *emit,
                       QmpDispatchReturn *return_cb)
 {
     assert(return_cb);
     assert(!session->return_cb);
 
-    json_message_parser_init(&session->parser, qmp_json_emit, session, NULL);
+    json_message_parser_init(&session->parser, emit ?: qmp_json_emit,
+                             session, NULL);
     session->cmds = cmds;
     session->return_cb = return_cb;
 }
diff --git a/qga/main.c b/qga/main.c
index 9cd27fc4b8..14e418f9a5 100644
--- a/qga/main.c
+++ b/qga/main.c
@@ -1319,7 +1319,7 @@ static GAState *initialize_agent(GAConfig *config, int socket_activation)
     s->command_state = ga_command_state_new();
     ga_command_state_init(s, s->command_state);
     ga_command_state_init_all(s->command_state);
-    qmp_session_init(&s->session, &ga_commands, dispatch_return_cb);
+    qmp_session_init(&s->session, &ga_commands, NULL, dispatch_return_cb);
 
 #ifndef _WIN32
     if (!register_signal_handlers()) {
diff --git a/qobject/json-streamer.c b/qobject/json-streamer.c
index 47dd7ea576..2a440f2a9e 100644
--- a/qobject/json-streamer.c
+++ b/qobject/json-streamer.c
@@ -100,8 +100,7 @@ out_emit:
 }
 
 void json_message_parser_init(JSONMessageParser *parser,
-                              void (*emit)(void *opaque, QObject *json,
-                                           Error *err),
+                              JSONMessageEmit *emit,
                               void *opaque, va_list *ap)
 {
     parser->emit = emit;
diff --git a/tests/test-qmp-cmds.c b/tests/test-qmp-cmds.c
index 3f41cc45bb..b4d0b0440a 100644
--- a/tests/test-qmp-cmds.c
+++ b/tests/test-qmp-cmds.c
@@ -121,7 +121,7 @@ static void test_dispatch_cmd(void)
     QmpSession session = { 0, };
     QDict *req = qdict_new();
 
-    qmp_session_init(&session, &qmp_commands, dispatch_cmd_return);
+    qmp_session_init(&session, &qmp_commands, NULL, dispatch_cmd_return);
     qdict_put_str(req, "execute", "user_def_cmd");
 
     qmp_dispatch(&session, QOBJECT(req), false);
@@ -135,7 +135,7 @@ static void test_dispatch_cmd_oob(void)
     QmpSession session = { 0, };
     QDict *req = qdict_new();
 
-    qmp_session_init(&session, &qmp_commands, dispatch_cmd_return);
+    qmp_session_init(&session, &qmp_commands, NULL, dispatch_cmd_return);
     qdict_put_str(req, "exec-oob", "test-flags-command");
 
     qmp_dispatch(&session, QOBJECT(req), true);
@@ -157,7 +157,8 @@ static void test_dispatch_cmd_failure(void)
     QDict *req = qdict_new();
     QDict *args = qdict_new();
 
-    qmp_session_init(&session, &qmp_commands, dispatch_cmd_failure_return);
+    qmp_session_init(&session, &qmp_commands, NULL,
+                     dispatch_cmd_failure_return);
     qdict_put_str(req, "execute", "user_def_cmd2");
 
     qmp_dispatch(&session, QOBJECT(req), false);
@@ -183,7 +184,7 @@ static void test_dispatch_cmd_success_response(void)
     QmpSession session = { 0, };
     QDict *req = qdict_new();
 
-    qmp_session_init(&session, &qmp_commands, (QmpDispatchReturn *)abort);
+    qmp_session_init(&session, &qmp_commands, NULL, (QmpDispatchReturn *)abort);
     qdict_put_str(req, "execute", "cmd-success-response");
 
     qmp_dispatch(&session, QOBJECT(req), false);
@@ -204,7 +205,7 @@ static QObject *test_qmp_dispatch(QDict *req)
     QmpSession session = { 0, };
     QObject *ret;
 
-    qmp_session_init(&session, &qmp_commands, dispatch_return);
+    qmp_session_init(&session, &qmp_commands, NULL, dispatch_return);
     qmp_dispatch(&session, QOBJECT(req), false);
     ret = dispatch_ret;
     dispatch_ret = NULL;
-- 
2.21.0.196.g041f5ea1cf