monitor: introduce HumanReadableText and HMP support

This provides a foundation on which to convert simple HMP commands to
use QMP. The QMP implementation will generate formatted text targeted
for human consumption, returning it in the HumanReadableText data type.

The HMP command handler will simply print out the formatted string
within the HumanReadableText data type. Since this will be an entirely
formulaic action in the case of HMP commands taking no arguments, a
custom command handler is provided.

Thus instead of registering a 'cmd' callback for the HMP command, a
'cmd_info_hrt' callback is provided, which will simply be a pointer
to the QMP implementation.

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

3 files changed, 19 insertions, 0 deletions

diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index a2cb002a3a..96d014826a 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -15,6 +15,7 @@
 #define HMP_H
 
 #include "qemu/readline.h"
+#include "qapi/qapi-types-common.h"
 
 bool hmp_handle_error(Monitor *mon, Error *err);
 
@@ -130,5 +131,7 @@ void hmp_replay_delete_break(Monitor *mon, const QDict *qdict);
 void hmp_replay_seek(Monitor *mon, const QDict *qdict);
 void hmp_info_dirty_rate(Monitor *mon, const QDict *qdict);
 void hmp_calc_dirty_rate(Monitor *mon, const QDict *qdict);
+void hmp_human_readable_text_helper(Monitor *mon,
+                                    HumanReadableText *(*qmp_handler)(Error **));
 
 #endif
diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h
index 1a8a369b50..12d395d62d 100644
--- a/include/monitor/monitor.h
+++ b/include/monitor/monitor.h
@@ -53,5 +53,7 @@ int64_t monitor_fdset_dup_fd_find(int dup_fd);
 
 void monitor_register_hmp(const char *name, bool info,
                           void (*cmd)(Monitor *mon, const QDict *qdict));
+void monitor_register_hmp_info_hrt(const char *name,
+                                   HumanReadableText *(*handler)(Error **errp));
 
 #endif /* MONITOR_H */
diff --git a/include/qapi/type-helpers.h b/include/qapi/type-helpers.h
new file mode 100644
index 0000000000..be1f181526
--- /dev/null
+++ b/include/qapi/type-helpers.h
@@ -0,0 +1,14 @@
+/*
+ * QAPI common helper functions
+ *
+ * This file provides helper functions related to types defined
+ * in the QAPI schema.
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ *
+ */
+
+#include "qapi/qapi-types-common.h"
+
+HumanReadableText *human_readable_text_from_str(GString *str);