# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1626124696 -7200
# Node ID 929003b4e133c8353335f2be79b3a0c308d3f8ab
# Parent  b584c94d252f871d25721d8315eb1350d7e33cb9
Simplified notification functionality slightly, introducing a notify_others
method, a special endpoint "role" enumeration, and removing special handling of
any "source" notifier when performing notifications.

diff -r b584c94d252f -r 929003b4e133 libfsserver/include/fsserver/notification.h
--- a/libfsserver/include/fsserver/notification.h	Mon Jul 12 22:52:52 2021 +0200
+++ b/libfsserver/include/fsserver/notification.h	Mon Jul 12 23:18:16 2021 +0200
@@ -50,7 +50,9 @@
 
     virtual ~NotificationSupport();
 
-    virtual void notify(unsigned int endpoint, notify_flags_t flags, l4_cap_idx_t source=L4_INVALID_CAP);
+    virtual void notify(unsigned int endpoint, notify_flags_t flags);
+
+    virtual void notify_others(unsigned int endpoint, notify_flags_t flags);
 
     virtual void subscribe(unsigned int endpoint, l4_cap_idx_t notifier, notify_flags_t flags);
 
diff -r b584c94d252f -r 929003b4e133 libfsserver/include/fsserver/pipe_paging.h
--- a/libfsserver/include/fsserver/pipe_paging.h	Mon Jul 12 22:52:52 2021 +0200
+++ b/libfsserver/include/fsserver/pipe_paging.h	Mon Jul 12 23:18:16 2021 +0200
@@ -69,14 +69,6 @@
     virtual offset_t region_size()
     { return _size; }
 
-    /* Notification support customised for pipes. */
-
-    virtual void notify(bool writing, notify_flags_t flags);
-
-    virtual void subscribe(bool writing, l4_cap_idx_t notifier, notify_flags_t flags);
-
-    virtual void unsubscribe(bool writing, l4_cap_idx_t notifier);
-
     /* Region management. */
 
     virtual PageMapper *add_region();
@@ -88,6 +80,14 @@
     /* Access management. */
 
     virtual int closed();
+
+    /* Special values for various arrays. */
+
+    enum PipePagingRoles : unsigned int
+    {
+        READER = 0,
+        WRITER = 1,
+    };
 };
 
 // vim: tabstop=4 expandtab shiftwidth=4
diff -r b584c94d252f -r 929003b4e133 libfsserver/lib/generic/notification.cc
--- a/libfsserver/lib/generic/notification.cc	Mon Jul 12 22:52:52 2021 +0200
+++ b/libfsserver/lib/generic/notification.cc	Mon Jul 12 23:18:16 2021 +0200
@@ -80,9 +80,9 @@
     }
 }
 
-/* Notify the other endpoint. */
+/* Notify a particular endpoint. */
 
-void NotificationSupport::notify(unsigned int endpoint, notify_flags_t flags, l4_cap_idx_t source)
+void NotificationSupport::notify(unsigned int endpoint, notify_flags_t flags)
 {
     /* Notify the endpoint or hold any notification for potential future
        subscription. */
@@ -95,12 +95,6 @@
 
             for (it = _notifiers[endpoint].begin(); it != _notifiers[endpoint].end(); it++)
             {
-                /* Avoid notifying the source of the notification if it is
-                   present in the list. */
-
-                if (l4_is_valid_cap(source) && (*it == source))
-                    continue;
-
                 client_Notifier notifier(*it);
 
                 notifier.notify(flags & _flags[endpoint]);
@@ -111,6 +105,15 @@
         _deferred[endpoint] = flags;
 }
 
+/* Notify the other endpoints. */
+
+void NotificationSupport::notify_others(unsigned int endpoint, notify_flags_t flags)
+{
+    for (unsigned int i = 0; i < _max_endpoints; i++)
+        if (i != endpoint)
+            notify(i, flags);
+}
+
 /* Release notifiers for each endpoint. */
 
 void NotificationSupport::release_notifiers()
diff -r b584c94d252f -r 929003b4e133 libfsserver/lib/pipes/pipe_pager.cc
--- a/libfsserver/lib/pipes/pipe_pager.cc	Mon Jul 12 22:52:52 2021 +0200
+++ b/libfsserver/lib/pipes/pipe_pager.cc	Mon Jul 12 23:18:16 2021 +0200
@@ -59,7 +59,7 @@
 
     /* Notify the other endpoint. */
 
-    _paging->notify(_writing, NOTIFY_PEER_CLOSED);
+    _paging->notify_others(_writing ? PipePaging::WRITER : PipePaging::READER, NOTIFY_PEER_CLOSED);
 }
 
 /* Support paging. */
@@ -157,7 +157,8 @@
 
     // NOTE: Perhaps employ a distinct event type for metadata updates.
 
-    _paging->notify(_writing, NOTIFY_CONTENT_AVAILABLE | NOTIFY_SPACE_AVAILABLE);
+    _paging->notify_others(_writing ? PipePaging::WRITER : PipePaging::READER,
+                           NOTIFY_CONTENT_AVAILABLE | NOTIFY_SPACE_AVAILABLE);
     return L4_EOK;
 }
 
@@ -170,13 +171,13 @@
     /* Readers can subscribe to new data (at end), and pipe closed events.
        Writers can subscribe to new space and pipe closed events. */
 
-    _paging->subscribe(_writing, notifier, flags);
+    _paging->subscribe(_writing ? PipePaging::WRITER : PipePaging::READER, notifier, flags);
     return L4_EOK;
 }
 
 long PipePager::unsubscribe(l4_cap_idx_t notifier)
 {
-    _paging->unsubscribe(_writing, notifier);
+    _paging->unsubscribe(_writing ? PipePaging::WRITER : PipePaging::READER, notifier);
     return L4_EOK;
 }
 
diff -r b584c94d252f -r 929003b4e133 libfsserver/lib/pipes/pipe_paging.cc
--- a/libfsserver/lib/pipes/pipe_paging.cc	Mon Jul 12 22:52:52 2021 +0200
+++ b/libfsserver/lib/pipes/pipe_paging.cc	Mon Jul 12 23:18:16 2021 +0200
@@ -43,29 +43,6 @@
         _regions[i] = NULL;
 }
 
-/* Subscribe to an endpoint's notifications using a notifier object. */
-
-void PipePaging::subscribe(bool writing, l4_cap_idx_t notifier, notify_flags_t flags)
-{
-    NotificationSupport::subscribe(writing ? 1 : 0, notifier, flags);
-}
-
-/* Unsubscribe from an endpoint's notifications. */
-
-void PipePaging::unsubscribe(bool writing, l4_cap_idx_t notifier)
-{
-    NotificationSupport::unsubscribe(writing ? 1 : 0, notifier);
-}
-
-/* Notify the other endpoint. */
-
-void PipePaging::notify(bool writing, notify_flags_t flags)
-{
-    /* Let the writer notify the reader, and the other way round. */
-
-    NotificationSupport::notify(writing ? 0 : 1, flags);
-}
-
 /* Return whether one or more endpoints have detached. */
 
 int PipePaging::closed()
@@ -142,7 +119,7 @@
 
     /* Let the writer notify the reader. */
 
-    notify(true, NOTIFY_CONTENT_AVAILABLE);
+    notify_others(PipePaging::WRITER, NOTIFY_CONTENT_AVAILABLE);
 
     /* Return the next region's mapper. */
 
@@ -177,7 +154,7 @@
 
     /* Let the reader notify the writer. */
 
-    notify(false, NOTIFY_SPACE_AVAILABLE);
+    notify_others(PipePaging::READER, NOTIFY_SPACE_AVAILABLE);
 
     /* Return the next region's mapper. */