gdbsupport, gdb: give names to observers

Give a name to each observer, this will help produce more meaningful
debug message.

gdbsupport/ChangeLog:

	* observable.h (class observable) <struct observer> <observer>:
	Add name parameter.
	<name>: New field.
	<attach>: Add name parameter, update all callers.

Change-Id: Ie0cc4664925215b8d2b09e026011b7803549fba0

2 files changed, 22 insertions, 8 deletions

diff --git a/gdbsupport/ChangeLog b/gdbsupport/ChangeLog
index bfbd152..0f3de6d 100644
--- a/gdbsupport/ChangeLog
+++ b/gdbsupport/ChangeLog
@@ -1,5 +1,12 @@
 2021-04-24  Simon Marchi  <simon.marchi@polymtl.ca>
 
+	* observable.h (class observable) <struct observer> <observer>:
+	Add name parameter.
+	<name>: New field.
+	<attach>: Add name parameter, update all callers.
+
+2021-04-24  Simon Marchi  <simon.marchi@polymtl.ca>
+
 	* observable.h (class observable) <struct observer>: New.
 	<detach, notify>: Update.
 	<m_observers>: Change type to vector of observers.
diff --git a/gdbsupport/observable.h b/gdbsupport/observable.h
index 1d19429..5e7846f 100644
--- a/gdbsupport/observable.h
+++ b/gdbsupport/observable.h
@@ -61,12 +61,13 @@ public:
 private:
   struct observer
   {
-    observer (const struct token *token, func_type func)
-      : token (token), func (func)
+    observer (const struct token *token, func_type func, const char *name)
+      : token (token), func (func), name (name)
     {}
 
     const struct token *token;
     func_type func;
+    const char *name;
   };
 
 public:
@@ -78,17 +79,23 @@ public:
   DISABLE_COPY_AND_ASSIGN (observable);
 
   /* Attach F as an observer to this observable.  F cannot be
-     detached.  */
-  void attach (const func_type &f)
+     detached.
+
+     NAME is the name of the observer, used for debug output purposes.  Its
+     lifetime must be at least as long as the observer is attached.  */
+  void attach (const func_type &f, const char *name)
   {
-    m_observers.emplace_back (nullptr, f);
+    m_observers.emplace_back (nullptr, f, name);
   }
 
   /* Attach F as an observer to this observable.  T is a reference to
-     a token that can be used to later remove F.  */
-  void attach (const func_type &f, const token &t)
+     a token that can be used to later remove F.
+
+     NAME is the name of the observer, used for debug output purposes.  Its
+     lifetime must be at least as long as the observer is attached.  */
+  void attach (const func_type &f, const token &t, const char *name)
   {
-    m_observers.emplace_back (&t, f);
+    m_observers.emplace_back (&t, f, name);
   }
 
   /* Remove observers associated with T from this observable.  T is