[PATCH 04/20] C++ify remote notification code

[Tom Tromey <tom at tromey dot com>]

This C++ifies the remote notification code -- replacing function
pointers with virtual methods and using unique_ptr.  This allows for
the removal of some cleanups.

gdb/ChangeLog
2019-02-13  Tom Tromey  <tom@tromey.com>

	* remote.c (struct stop_reply_deleter): Remove.
	(stop_reply_up): Update.
	(struct stop_reply): Derive from notif_event.  Don't typedef.
	<regcache>: Now a std::vector.
	(stop_reply_xfree): Remove.
	(stop_reply::~stop_reply): Rename from stop_reply_dtr.
	(remote_notif_stop_alloc_reply): Return a unique_ptr.  Use new.
	(remote_target::discard_pending_stop_replies): Use delete.
	(remote_target::remote_parse_stop_reply): Update.
	(remote_target::process_stop_reply): Update.
	* remote-notif.h (struct notif_event): Add virtual destructor.
	Remove "dtr" member.
	(struct notif_client) <alloc_event>: Return a unique_ptr.
	(notif_event_xfree): Don't declare.
	* remote-notif.c (remote_notif_ack, remote_notif_parse): Update.
	(notif_event_xfree, do_notif_event_xfree): Remove.
	(remote_notif_state_xfree): Update.
---
 gdb/ChangeLog      | 20 ++++++++++++
 gdb/remote-notif.c | 42 ++++--------------------
 gdb/remote-notif.h | 11 +++----
 gdb/remote.c       | 80 +++++++++++++---------------------------------
 4 files changed, 54 insertions(+), 99 deletions(-)

diff --git a/gdb/remote-notif.c b/gdb/remote-notif.c
index ae9a94d9c94..5a70ca128d5 100644
--- a/gdb/remote-notif.c
+++ b/gdb/remote-notif.c
@@ -52,8 +52,6 @@ static struct notif_client *notifs[] =
 
 gdb_static_assert (ARRAY_SIZE (notifs) == REMOTE_NOTIF_LAST);
 
-static void do_notif_event_xfree (void *arg);
-
 /* Parse the BUF for the expected notification NC, and send packet to
    acknowledge.  */
 
@@ -61,18 +59,14 @@ void
 remote_notif_ack (remote_target *remote,
 		  struct notif_client *nc, const char *buf)
 {
-  struct notif_event *event = nc->alloc_event ();
-  struct cleanup *old_chain
-    = make_cleanup (do_notif_event_xfree, event);
+  std::unique_ptr<struct notif_event> event = nc->alloc_event ();
 
   if (notif_debug)
     fprintf_unfiltered (gdb_stdlog, "notif: ack '%s'\n",
 			nc->ack_command);
 
-  nc->parse (remote, nc, buf, event);
-  nc->ack (remote, nc, buf, event);
-
-  discard_cleanups (old_chain);
+  nc->parse (remote, nc, buf, event.get ());
+  nc->ack (remote, nc, buf, event.release ());
 }
 
 /* Parse the BUF for the expected notification NC.  */
@@ -81,17 +75,14 @@ struct notif_event *
 remote_notif_parse (remote_target *remote,
 		    struct notif_client *nc, const char *buf)
 {
-  struct notif_event *event = nc->alloc_event ();
-  struct cleanup *old_chain
-    = make_cleanup (do_notif_event_xfree, event);
+  std::unique_ptr<struct notif_event> event = nc->alloc_event ();
 
   if (notif_debug)
     fprintf_unfiltered (gdb_stdlog, "notif: parse '%s'\n", nc->name);
 
-  nc->parse (remote, nc, buf, event);
+  nc->parse (remote, nc, buf, event.get ());
 
-  discard_cleanups (old_chain);
-  return event;
+  return event.release ();
 }
 
 DEFINE_QUEUE_P (notif_client_p);
@@ -216,25 +207,6 @@ handle_notification (struct remote_notif_state *state, const char *buf)
     }
 }
 
-/* Invoke destructor of EVENT and xfree it.  */
-
-void
-notif_event_xfree (struct notif_event *event)
-{
-  if (event != NULL && event->dtr != NULL)
-    event->dtr (event);
-
-  xfree (event);
-}
-
-/* Cleanup wrapper.  */
-
-static void
-do_notif_event_xfree (void *arg)
-{
-  notif_event_xfree ((struct notif_event *) arg);
-}
-
 /* Return an allocated remote_notif_state.  */
 
 struct remote_notif_state *
@@ -269,7 +241,7 @@ remote_notif_state_xfree (struct remote_notif_state *state)
     delete_async_event_handler (&state->get_pending_events_token);
 
   for (i = 0; i < REMOTE_NOTIF_LAST; i++)
-    notif_event_xfree (state->pending_event[i]);
+    delete state->pending_event[i];
 
   xfree (state);
 }
diff --git a/gdb/remote-notif.h b/gdb/remote-notif.h
index d7663274a4a..cb698626cec 100644
--- a/gdb/remote-notif.h
+++ b/gdb/remote-notif.h
@@ -20,15 +20,16 @@
 #ifndef REMOTE_NOTIF_H
 #define REMOTE_NOTIF_H
 
+#include <memory>
 #include "common/queue.h"
 
 /* An event of a type of async remote notification.  */
 
 struct notif_event
 {
-  /* Destructor.  Release everything from SELF, but not SELF
-     itself.  */
-  void (*dtr) (struct notif_event *self);
+  virtual ~notif_event ()
+  {
+  }
 };
 
 /* ID of the notif_client.  */
@@ -70,7 +71,7 @@ typedef struct notif_client
 				 struct notif_client *self);
 
   /* Allocate an event.  */
-  struct notif_event *(*alloc_event) (void);
+  std::unique_ptr<struct notif_event> (*alloc_event) ();
 
   /* Id of this notif_client.  */
   const enum REMOTE_NOTIF_ID id;
@@ -112,8 +113,6 @@ struct notif_event *remote_notif_parse (remote_target *remote,
 					notif_client *nc,
 					const char *buf);
 
-void notif_event_xfree (struct notif_event *event);
-
 void handle_notification (struct remote_notif_state *notif_state,
 			  const char *buf);
 
diff --git a/gdb/remote.c b/gdb/remote.c
index 18e678d07af..a250a4e0625 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -96,17 +96,7 @@ struct protocol_feature;
 struct packet_reg;
 
 struct stop_reply;
-static void stop_reply_xfree (struct stop_reply *);
-
-struct stop_reply_deleter
-{
-  void operator() (stop_reply *r) const
-  {
-    stop_reply_xfree (r);
-  }
-};
-
-typedef std::unique_ptr<stop_reply, stop_reply_deleter> stop_reply_up;
+typedef std::unique_ptr<struct stop_reply> stop_reply_up;
 
 /* Generic configuration support for packets the stub optionally
    supports.  Allows the user to specify the use of the packet as well
@@ -6817,11 +6807,9 @@ remote_console_output (const char *msg)
   gdb_flush (gdb_stdtarg);
 }
 
-DEF_VEC_O(cached_reg_t);
-
-typedef struct stop_reply
+struct stop_reply : public notif_event
 {
-  struct notif_event base;
+  ~stop_reply ();
 
   /* The identifier of the thread about this event  */
   ptid_t ptid;
@@ -6840,20 +6828,14 @@ typedef struct stop_reply
      efficient for those targets that provide critical registers as
      part of their normal status mechanism (as another roundtrip to
      fetch them is avoided).  */
-  VEC(cached_reg_t) *regcache;
+  std::vector<cached_reg_t> regcache;
 
   enum target_stop_reason stop_reason;
 
   CORE_ADDR watch_data_address;
 
   int core;
-} *stop_reply_p;
-
-static void
-stop_reply_xfree (struct stop_reply *r)
-{
-  notif_event_xfree ((struct notif_event *) r);
-}
+};
 
 /* Return the length of the stop reply queue.  */
 
@@ -6905,30 +6887,16 @@ remote_notif_stop_can_get_pending_events (remote_target *remote,
   return 0;
 }
 
-static void
-stop_reply_dtr (struct notif_event *event)
+stop_reply::~stop_reply ()
 {
-  struct stop_reply *r = (struct stop_reply *) event;
-  cached_reg_t *reg;
-  int ix;
-
-  for (ix = 0;
-       VEC_iterate (cached_reg_t, r->regcache, ix, reg);
-       ix++)
-    xfree (reg->data);
-
-  VEC_free (cached_reg_t, r->regcache);
+  for (cached_reg_t &reg : regcache)
+    xfree (reg.data);
 }
 
-static struct notif_event *
-remote_notif_stop_alloc_reply (void)
+static std::unique_ptr<struct notif_event>
+remote_notif_stop_alloc_reply ()
 {
-  /* We cast to a pointer to the "base class".  */
-  struct notif_event *r = (struct notif_event *) XNEW (struct stop_reply);
-
-  r->dtr = stop_reply_dtr;
-
-  return r;
+  return std::unique_ptr<struct notif_event> (new struct stop_reply ());
 }
 
 /* A client of notification Stop.  */
@@ -7071,7 +7039,7 @@ remote_target::discard_pending_stop_replies (struct inferior *inf)
   /* Discard the in-flight notification.  */
   if (reply != NULL && reply->ptid.pid () == inf->pid)
     {
-      stop_reply_xfree (reply);
+      delete reply;
       rns->pending_event[notif_client_stop.id] = NULL;
     }
 
@@ -7215,7 +7183,7 @@ remote_target::remote_parse_stop_reply (const char *buf, stop_reply *event)
   event->ws.kind = TARGET_WAITKIND_IGNORE;
   event->ws.value.integer = 0;
   event->stop_reason = TARGET_STOPPED_BY_NO_REASON;
-  event->regcache = NULL;
+  event->regcache.clear ();
   event->core = -1;
 
   switch (buf[0])
@@ -7449,7 +7417,7 @@ Packet: '%s'\n"),
 		  if (fieldsize < register_size (event->arch, reg->regnum))
 		    warning (_("Remote reply is too short: %s"), buf);
 
-		  VEC_safe_push (cached_reg_t, event->regcache, &cached_reg);
+		  event->regcache.push_back (cached_reg);
 		}
 	      else
 		{
@@ -7665,22 +7633,18 @@ remote_target::process_stop_reply (struct stop_reply *stop_reply,
       && status->kind != TARGET_WAITKIND_NO_RESUMED)
     {
       /* Expedited registers.  */
-      if (stop_reply->regcache)
+      if (!stop_reply->regcache.empty ())
 	{
 	  struct regcache *regcache
 	    = get_thread_arch_regcache (ptid, stop_reply->arch);
-	  cached_reg_t *reg;
-	  int ix;
 
-	  for (ix = 0;
-	       VEC_iterate (cached_reg_t, stop_reply->regcache, ix, reg);
-	       ix++)
-	  {
-	    regcache->raw_supply (reg->num, reg->data);
-	    xfree (reg->data);
-	  }
+	  for (cached_reg_t &reg : stop_reply->regcache)
+	    {
+	      regcache->raw_supply (reg.num, reg.data);
+	      xfree (reg.data);
+	    }
 
-	  VEC_free (cached_reg_t, stop_reply->regcache);
+	  stop_reply->regcache.clear ();
 	}
 
       remote_notice_new_inferior (ptid, 0);
@@ -7691,7 +7655,7 @@ remote_target::process_stop_reply (struct stop_reply *stop_reply,
       remote_thr->vcont_resumed = 0;
     }
 
-  stop_reply_xfree (stop_reply);
+  delete stop_reply;
   return ptid;
 }
 
-- 
2.17.2