[PATCH v6 05/25] QmpSession: add json parser and use it in qga

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

Move JSON parser to QmpSession, and implement a simple handler to check
the parsed tokens and call qmp_dispatch(). This is enough for a simple
QMP client, like QGA.

The QEMU monitor has more complicated handling of dispatching which
will be addressed in a following patch to benefit from more common
code.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 include/qapi/qmp/dispatch.h |  7 +++++++
 qapi/qmp-dispatch.c         | 19 +++++++++++++++++++
 qga/main.c                  | 31 +------------------------------
 3 files changed, 27 insertions(+), 30 deletions(-)

diff --git a/include/qapi/qmp/dispatch.h b/include/qapi/qmp/dispatch.h
index d1ce631a93..c84edff7d2 100644
--- a/include/qapi/qmp/dispatch.h
+++ b/include/qapi/qmp/dispatch.h
@@ -15,6 +15,7 @@
 #define QAPI_QMP_DISPATCH_H
 
 #include "qemu/queue.h"
+#include "qapi/qmp/json-parser.h"
 
 typedef void (QmpCommandFunc)(QDict *, QObject **, Error **);
 
@@ -42,6 +43,7 @@ typedef void (QmpDispatchReturn) (QmpSession *session, QDict *rsp);
 
 struct QmpSession {
     const QmpCommandList *cmds;
+    JSONMessageParser parser;
     QmpDispatchReturn *return_cb;
 };
 
@@ -52,6 +54,11 @@ const QmpCommand *qmp_find_command(const QmpCommandList *cmds,
 void qmp_session_init(QmpSession *session,
                       const QmpCommandList *cmds,
                       QmpDispatchReturn *return_cb);
+static inline void
+qmp_session_feed(QmpSession *session, const char *buf, size_t count)
+{
+    json_message_parser_feed(&session->parser, buf, count);
+}
 void qmp_session_destroy(QmpSession *session);
 void qmp_disable_command(QmpCommandList *cmds, const char *name);
 void qmp_enable_command(QmpCommandList *cmds, const char *name);
diff --git a/qapi/qmp-dispatch.c b/qapi/qmp-dispatch.c
index 1314f4929f..f8c491924d 100644
--- a/qapi/qmp-dispatch.c
+++ b/qapi/qmp-dispatch.c
@@ -164,6 +164,23 @@ bool qmp_is_oob(const QDict *dict)
         && !qdict_haskey(dict, "execute");
 }
 
+static void qmp_json_emit(void *opaque, QObject *obj, Error *err)
+{
+    QmpSession *session = opaque;
+
+    assert(!obj != !err);
+
+    if (err) {
+        QDict *rsp = qmp_error_response(err);
+        session->return_cb(session, rsp);
+        qobject_unref(rsp);
+    } else {
+        qmp_dispatch(session, obj, false);
+    }
+
+    qobject_unref(obj);
+}
+
 void qmp_session_init(QmpSession *session,
                       const QmpCommandList *cmds,
                       QmpDispatchReturn *return_cb)
@@ -171,6 +188,7 @@ void qmp_session_init(QmpSession *session,
     assert(return_cb);
     assert(!session->return_cb);
 
+    json_message_parser_init(&session->parser, qmp_json_emit, session, NULL);
     session->cmds = cmds;
     session->return_cb = return_cb;
 }
@@ -183,6 +201,7 @@ void qmp_session_destroy(QmpSession *session)
 
     session->cmds = NULL;
     session->return_cb = NULL;
+    json_message_parser_destroy(&session->parser);
 }
 
 void qmp_dispatch(QmpSession *session, QObject *request, bool allow_oob)
diff --git a/qga/main.c b/qga/main.c
index c291d06491..057368eb16 100644
--- a/qga/main.c
+++ b/qga/main.c
@@ -19,7 +19,6 @@
 #include <sys/wait.h>
 #endif
 #include "qemu-common.h"
-#include "qapi/qmp/json-parser.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qjson.h"
 #include "qapi/qmp/qstring.h"
@@ -75,7 +74,6 @@ typedef struct GAConfig GAConfig;
 
 struct GAState {
     QmpSession session;
-    JSONMessageParser parser;
     GMainLoop *main_loop;
     GAChannel *channel;
     bool virtio; /* fastpath to check for virtio to deal with poll() quirks */
@@ -567,31 +565,6 @@ static void dispatch_return_cb(QmpSession *session, QDict *rsp)
     }
 }
 
-/* handle requests/control events coming in over the channel */
-static void process_event(void *opaque, QObject *obj, Error *err)
-{
-    GAState *s = opaque;
-    int ret;
-
-    g_debug("process_event: called");
-    assert(!obj != !err);
-
-    if (err) {
-        QDict *rsp = qmp_error_response(err);
-
-        ret = send_response(s, rsp);
-        if (ret < 0) {
-            g_warning("error sending error response: %s", strerror(-ret));
-        }
-        qobject_unref(rsp);
-    } else {
-        g_debug("processing command");
-        qmp_dispatch(&s->session, obj, false);
-    }
-
-    qobject_unref(obj);
-}
-
 /* false return signals GAChannel to close the current client connection */
 static gboolean channel_event_cb(GIOCondition condition, gpointer data)
 {
@@ -607,7 +580,7 @@ static gboolean channel_event_cb(GIOCondition condition, gpointer data)
     case G_IO_STATUS_NORMAL:
         buf[count] = 0;
         g_debug("read data, count: %d, data: %s", (int)count, buf);
-        json_message_parser_feed(&s->parser, (char *)buf, (int)count);
+        qmp_session_feed(&s->session, (char *)buf, (int)count);
         break;
     case G_IO_STATUS_EOF:
         g_debug("received EOF");
@@ -1346,7 +1319,6 @@ 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);
-    json_message_parser_init(&s->parser, process_event, s, NULL);
     qmp_session_init(&s->session, &ga_commands, dispatch_return_cb);
 
 #ifndef _WIN32
@@ -1382,7 +1354,6 @@ static void cleanup_agent(GAState *s)
         qmp_session_destroy(&s->session);
         ga_command_state_cleanup_all(s->command_state);
         ga_command_state_free(s->command_state);
-        json_message_parser_destroy(&s->parser);
     }
     g_free(s->pstate_filepath);
     g_free(s->state_filepath_isfrozen);
-- 
2.24.0