# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1626038468 -7200
# Node ID b287ba4e828bba305497a01bd3a5f6f94c8a2c37
# Parent  9392b442245f4eb194a59d778afc2b62789aa854
Moved notification functionality to a separate base class.

diff -r 9392b442245f -r b287ba4e828b libfsserver/include/fsserver/notification.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libfsserver/include/fsserver/notification.h	Sun Jul 11 23:21:08 2021 +0200
@@ -0,0 +1,60 @@
+/*
+ * Notification support.
+ *
+ * Copyright (C) 2021 Paul Boddie <paul@boddie.org.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA  02110-1301, USA
+ */
+
+#pragma once
+
+#include <set>
+
+#include <systypes/base.h>
+
+
+
+/* Notification support, allowing pipe or file users to receive events due to
+   activity on those objects. */
+
+class NotificationSupport
+{
+protected:
+    /* Endpoint count. */
+
+    unsigned int _max_endpoints;
+
+    /* Notification endpoints and flags, set up at initialisation for the
+       appropriate number of endpoints. */
+
+    std::set<l4_cap_idx_t> *_notifiers;
+    notify_flags_t *_flags, *_deferred;
+
+    virtual void release_notifiers();
+
+public:
+    explicit NotificationSupport(unsigned int endpoints);
+
+    virtual ~NotificationSupport();
+
+    virtual void notify(unsigned int endpoint, notify_flags_t flags, l4_cap_idx_t source=L4_INVALID_CAP);
+
+    virtual void subscribe(unsigned int endpoint, l4_cap_idx_t notifier, notify_flags_t flags);
+
+    virtual void unsubscribe(unsigned int endpoint, l4_cap_idx_t notifier);
+};
+
+// vim: tabstop=4 expandtab shiftwidth=4
diff -r 9392b442245f -r b287ba4e828b libfsserver/include/fsserver/pipe_paging.h
--- a/libfsserver/include/fsserver/pipe_paging.h	Sun Jul 11 23:11:39 2021 +0200
+++ b/libfsserver/include/fsserver/pipe_paging.h	Sun Jul 11 23:21:08 2021 +0200
@@ -23,6 +23,7 @@
 
 #include <set>
 
+#include <fsserver/notification.h>
 #include <fsserver/page_mapper.h>
 #include <fsserver/pages.h>
 #include <fsserver/pipe_accessor.h>
@@ -32,7 +33,7 @@
 /* Pipe paging support, maintaining the sequence of active regions or sections
    in a pipe. */
 
-class PipePaging
+class PipePaging : public NotificationSupport
 {
 protected:
     Memory *_memory;
@@ -56,11 +57,6 @@
 
     unsigned int _endpoints = 2;
 
-    /* Notification endpoints. */
-
-    std::set<l4_cap_idx_t> _notifiers[2];
-    notify_flags_t _flags[2], _deferred[2];
-
     /* Common functionality. */
 
     virtual void discard_region(unsigned int i);
@@ -73,7 +69,7 @@
     virtual offset_t region_size()
     { return _size; }
 
-    /* Notification support. */
+    /* Notification support customised for pipes. */
 
     virtual void notify(bool writing, notify_flags_t flags);
 
diff -r 9392b442245f -r b287ba4e828b libfsserver/lib/Makefile
--- a/libfsserver/lib/Makefile	Sun Jul 11 23:11:39 2021 +0200
+++ b/libfsserver/lib/Makefile	Sun Jul 11 23:21:08 2021 +0200
@@ -52,6 +52,7 @@
 					files/test_file_accessor.cc \
 					files/test_file_opener.cc \
 					generic/accessor.cc \
+					generic/notification.cc \
 					generic/pager.cc \
 					generic/resource_server.cc \
 					generic/simple_pager.cc \
diff -r 9392b442245f -r b287ba4e828b libfsserver/lib/generic/notification.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libfsserver/lib/generic/notification.cc	Sun Jul 11 23:21:08 2021 +0200
@@ -0,0 +1,129 @@
+/*
+ * Notification support.
+ *
+ * Copyright (C) 2021 Paul Boddie <paul@boddie.org.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA  02110-1301, USA
+ */
+
+#include <ipc/cap_alloc.h>
+
+#include "notification.h"
+#include "notifier_client.h"
+
+
+
+/* Initialise endpoints and flags for notifications. */
+
+NotificationSupport::NotificationSupport(unsigned int endpoints)
+: _max_endpoints(endpoints)
+{
+    _notifiers = new std::set<l4_cap_idx_t>[endpoints];
+    _flags = new notify_flags_t[endpoints];
+    _deferred = new notify_flags_t[endpoints];
+
+    for (unsigned int endpoint = 0; endpoint < _max_endpoints; endpoint++)
+    {
+        _flags[endpoint] = 0;
+        _deferred[endpoint] = 0;
+    }
+}
+
+NotificationSupport::~NotificationSupport()
+{
+    delete _notifiers;
+    delete _flags;
+    delete _deferred;
+}
+
+/* Subscribe to an endpoint's notifications using a notification endpoint. */
+
+void NotificationSupport::subscribe(unsigned int endpoint, l4_cap_idx_t notifier, notify_flags_t flags)
+{
+    _notifiers[endpoint].insert(notifier);
+    _flags[endpoint] = flags;
+
+    /* Send deferred conditions held from before subscription occurred. */
+
+    if (_deferred[endpoint])
+    {
+        notify(endpoint, _deferred[endpoint]);
+        _deferred[endpoint] = 0;
+    }
+}
+
+/* Unsubscribe from an endpoint's notifications. */
+
+void NotificationSupport::unsubscribe(unsigned int endpoint, l4_cap_idx_t notifier)
+{
+    std::set<l4_cap_idx_t>::iterator it = _notifiers[endpoint].find(notifier);
+
+    if (it != _notifiers[endpoint].end())
+    {
+        _notifiers[endpoint].erase(it);
+        _flags[endpoint] = 0;
+        _deferred[endpoint] = 0;
+        ipc_cap_free_um(notifier);
+    }
+}
+
+/* Notify the other endpoint. */
+
+void NotificationSupport::notify(unsigned int endpoint, notify_flags_t flags, l4_cap_idx_t source)
+{
+    /* Notify the endpoint or hold any notification for potential future
+       subscription. */
+
+    if (!_notifiers[endpoint].empty())
+    {
+        if (flags & _flags[endpoint])
+        {
+            std::set<l4_cap_idx_t>::iterator it;
+
+            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]);
+            }
+        }
+    }
+    else
+        _deferred[endpoint] = flags;
+}
+
+/* Release notifiers for each endpoint. */
+
+void NotificationSupport::release_notifiers()
+{
+    for (unsigned int endpoint = 0; endpoint < _max_endpoints; endpoint++)
+    {
+        std::set<l4_cap_idx_t>::iterator it;
+
+        for (it = _notifiers[endpoint].begin(); it != _notifiers[endpoint].end(); it++)
+            ipc_cap_free_um(*it);
+
+        _notifiers[endpoint].clear();
+    }
+}
+
+// vim: tabstop=4 expandtab shiftwidth=4
diff -r 9392b442245f -r b287ba4e828b libfsserver/lib/pipes/pipe_paging.cc
--- a/libfsserver/lib/pipes/pipe_paging.cc	Sun Jul 11 23:11:39 2021 +0200
+++ b/libfsserver/lib/pipes/pipe_paging.cc	Sun Jul 11 23:21:08 2021 +0200
@@ -19,7 +19,6 @@
  * Boston, MA  02110-1301, USA
  */
 
-#include <ipc/cap_alloc.h>
 #include <mem/memory_preallocated.h>
 
 #include "page_queue_partitioned.h"
@@ -30,7 +29,7 @@
 
 
 PipePaging::PipePaging(Memory *memory, offset_t size)
-: _memory(NULL), _size(size)
+: NotificationSupport(2), _memory(NULL), _size(size)
 {
     /* Reserve space for two pipe regions. */
 
@@ -42,49 +41,20 @@
 
     for (unsigned int i = 0; i < 2; i++)
         _regions[i] = NULL;
-
-    /* Initialise endpoints and flags for notifications. */
-
-    for (unsigned int i = 0; i < 2; i++)
-    {
-        _flags[i] = 0;
-        _deferred[i] = 0;
-    }
 }
 
-/* Subscribe to an endpoint's notifications using a notification endpoint. */
+/* Subscribe to an endpoint's notifications using a notifier object. */
 
 void PipePaging::subscribe(bool writing, l4_cap_idx_t notifier, notify_flags_t flags)
 {
-    int i = writing ? 1 : 0;
-
-    _notifiers[i].insert(notifier);
-    _flags[i] = flags;
-
-    /* Send deferred conditions on behalf of the other endpoint held before
-       subscription occurred. */
-
-    if (_deferred[i])
-    {
-        notify(!writing, _deferred[i]);
-        _deferred[i] = 0;
-    }
+    NotificationSupport::subscribe(writing ? 1 : 0, notifier, flags);
 }
 
 /* Unsubscribe from an endpoint's notifications. */
 
 void PipePaging::unsubscribe(bool writing, l4_cap_idx_t notifier)
 {
-    int i = writing ? 1 : 0;
-    std::set<l4_cap_idx_t>::iterator it = _notifiers[i].find(notifier);
-
-    if (it != _notifiers[i].end())
-    {
-        _notifiers[i].erase(it);
-        _flags[i] = 0;
-        _deferred[i] = 0;
-        ipc_cap_free_um(notifier);
-    }
+    NotificationSupport::unsubscribe(writing ? 1 : 0, notifier);
 }
 
 /* Notify the other endpoint. */
@@ -93,27 +63,7 @@
 {
     /* Let the writer notify the reader, and the other way round. */
 
-    int i = writing ? 0 : 1;
-
-    /* Notify the other endpoint or hold any notification for potential future
-       subscription. */
-
-    if (!_notifiers[i].empty())
-    {
-        if (flags & _flags[i])
-        {
-            std::set<l4_cap_idx_t>::iterator it;
-
-            for (it = _notifiers[i].begin(); it != _notifiers[i].end(); it++)
-            {
-                client_Notifier notifier(*it);
-
-                notifier.notify(flags & _flags[i]);
-            }
-        }
-    }
-    else
-        _deferred[i] = flags;
+    NotificationSupport::notify(writing ? 0 : 1, flags);
 }
 
 /* Return whether one or more endpoints have detached. */
@@ -156,15 +106,7 @@
 
     /* Release notifiers. */
 
-    for (unsigned int i = 0; i < 2; i++)
-    {
-        std::set<l4_cap_idx_t>::iterator it;
-
-        for (it = _notifiers[i].begin(); it != _notifiers[i].end(); it++)
-            ipc_cap_free_um(*it);
-
-        _notifiers[i].clear();
-    }
+    release_notifiers();
 
     /* Delete the page collection and related objects. */