Replace deprecated_target_wait_hook by observers

Commit b60cea7 (Make target_wait options use enum flags) broke
deprecated_target_wait_hook usage: there's a commit comment telling
this hook has not been converted.

Rather than trying to mend it, this patch replaces the hook by two
target_wait observers:

target_pre_wait (ptid_t ptid)
target_post_wait (ptid_t event_ptid)

Upon target_wait entry, target_pre_wait is notified with the ptid
passed to target_wait. Upon exit, target_post_wait is notified with
the event ptid returned by target_wait. Should an exception occur,
event_ptid is null_ptid.

This change benefits to Insight (out-of-tree): there's no real use of the
late hook in gdb itself.

1 files changed, 13 insertions, 1 deletions

diff --git a/gdb/target.c b/gdb/target.c
index 658698b4e2b..e3df9275c9a 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -26,6 +26,7 @@
 #include "symtab.h"
 #include "inferior.h"
 #include "infrun.h"
+#include "observable.h"
 #include "bfd.h"
 #include "symfile.h"
 #include "objfiles.h"
@@ -2609,7 +2610,18 @@ target_wait (ptid_t ptid, struct target_waitstatus *status,
   if (!target_can_async_p (target))
     gdb_assert ((options & TARGET_WNOHANG) == 0);
 
-  return target->wait (ptid, status, options);
+  try
+    {
+      gdb::observers::target_pre_wait.notify (ptid);
+      ptid_t event_ptid = target->wait (ptid, status, options);
+      gdb::observers::target_post_wait.notify (event_ptid);
+      return event_ptid;
+    }
+  catch (...)
+    {
+      gdb::observers::target_post_wait.notify (null_ptid);
+      throw;
+    }
 }
 
 /* See target.h.  */