Refactor PollableCondition to be portable; match PollableQueue to it; initial port on Linux

git-svn-id: https://svn.apache.org/repos/asf/qpid/branches/win-pollable-condition@745121 13f79535-47bb-0310-9956-ffa450edef68

6 files changed, 183 insertions, 94 deletions

diff --git a/qpid/cpp/src/Makefile.am b/qpid/cpp/src/Makefile.am
index d5b53dc502..4ae1af0afb 100644
--- a/qpid/cpp/src/Makefile.am
+++ b/qpid/cpp/src/Makefile.am
@@ -139,7 +139,6 @@ posix_plat_hdr = \
   qpid/sys/posix/PrivatePosix.h \
   qpid/sys/posix/Mutex.h \
   qpid/sys/posix/Fork.h \
-  qpid/sys/posix/PollableCondition.h \
   qpid/sys/posix/IntegerTypes.h \
   qpid/sys/posix/Time.h
 
diff --git a/qpid/cpp/src/qpid/sys/PollableCondition.h b/qpid/cpp/src/qpid/sys/PollableCondition.h
index 56d38f90da..49e84e6cb0 100644
--- a/qpid/cpp/src/qpid/sys/PollableCondition.h
+++ b/qpid/cpp/src/qpid/sys/PollableCondition.h
@@ -22,7 +22,57 @@
  *
  */
 
-// Currently only has a posix implementation, add #ifdefs for other platforms as needed.
-#include "posix/PollableCondition.h"
+#include "qpid/sys/Poller.h"
+#include <boost/function.hpp>
+#include <boost/shared_ptr.hpp>
+
+
+namespace qpid {
+namespace sys {
+
+class PollableConditionPrivate;
+
+class PollableCondition {
+public:
+    typedef boost::function1<void, PollableCondition&> Callback;
+
+    PollableCondition(const Callback& cb,
+                      const boost::shared_ptr<sys::Poller>& poller);
+
+    ~PollableCondition();
+
+    /**
+     * Set the condition. Triggers callback to Callback from Poller.
+     * When callback is made, condition is suspended. Call rearm() to
+     * resume reacting to the condition.
+     */
+    void set();
+
+    /**
+     * Get the current state of the condition, then clear it.
+     *
+     * @return The state of the condition before it was cleared.
+     */
+    bool clear();
+
+    /**
+     * Temporarily suspend the ability for the poller to react to the
+     * condition. It can be rearm()ed later.
+     */
+    void disarm();
+
+    /**
+     * Reset the ability for the poller to react to the condition.
+     */
+    void rearm();
+
+ private:
+    PollableConditionPrivate *impl;
+
+    Callback callback;
+    boost::shared_ptr<sys::Poller> poller;
+};
+
+}} // namespace qpid::sys
 
 #endif  /*!QPID_SYS_POLLABLECONDITION_H*/
diff --git a/qpid/cpp/src/qpid/sys/PollableQueue.h b/qpid/cpp/src/qpid/sys/PollableQueue.h
index b5ff98c2c7..a23cc5137a 100644
--- a/qpid/cpp/src/qpid/sys/PollableQueue.h
+++ b/qpid/cpp/src/qpid/sys/PollableQueue.h
@@ -23,8 +23,6 @@
  */
 
 #include "qpid/sys/PollableCondition.h"
-#include "qpid/sys/Dispatcher.h"
-#include "qpid/sys/DispatchHandle.h"
 #include "qpid/sys/Monitor.h"
 #include "qpid/sys/Thread.h"
 #include <boost/function.hpp>
@@ -38,9 +36,10 @@ namespace sys {
 class Poller;
 
 /**
- * A queue that can be polled by sys::Poller.  Any thread can push to
- * the queue, on wakeup the poller thread processes all items on the
- * queue by passing them to a callback in a batch.
+ * A queue whose item processing is dispatched by sys::Poller.
+ * Any thread can push to the queue; items pushed trigger an event the Poller
+ * recognizes. When a Poller I/O thread dispatches the event, a
+ * user-specified callback is invoked with all items on the queue.
  */
 template <class T>
 class PollableQueue {
@@ -50,12 +49,21 @@ class PollableQueue {
 
     /**
      * Callback to process a batch of items from the queue.
-     * @param values to process, any items remaining after call are put back on the queue.
+     *
+     * @param values  Queue of values to process. Any items remaining
+     *                on return from Callback are put back on the queue.
      */
     typedef boost::function<void (Queue& values)> Callback;
 
-    /** When the queue is selected by the poller, values are passed to callback cb. */
-    PollableQueue(const Callback& cb, const boost::shared_ptr<sys::Poller>& poller);
+    /**
+     * Constructor; sets necessary parameters.
+     *
+     * @param cb      Callback that will be called to process items on the
+     *                queue. Will be called from a Poller I/O thread.
+     * @param poller  Poller to use for dispatching queue events.
+     */
+    PollableQueue(const Callback& cb,
+                  const boost::shared_ptr<sys::Poller>& poller);
 
     ~PollableQueue();
     
@@ -85,14 +93,12 @@ class PollableQueue {
     typedef sys::Monitor::ScopedLock ScopedLock;
     typedef sys::Monitor::ScopedUnlock ScopedUnlock;
 
-    void dispatch(sys::DispatchHandle&);
+    void dispatch(PollableCondition& cond);
     void process();
     
     mutable sys::Monitor lock;
     Callback callback;
-    boost::shared_ptr<sys::Poller> poller;
     PollableCondition condition;
-    DispatchHandleRef handle;
     Queue queue, batch;
     Thread dispatcher;
     bool stopped;
@@ -100,11 +106,10 @@ class PollableQueue {
 
 template <class T> PollableQueue<T>::PollableQueue(
     const Callback& cb, const boost::shared_ptr<sys::Poller>& p) 
-    : callback(cb), poller(p),
-      handle(condition, boost::bind(&PollableQueue<T>::dispatch, this, _1), 0, 0), stopped(true)
+  : callback(cb),
+    condition(boost::bind(&PollableQueue<T>::dispatch, this, _1), p),
+    stopped(true)
 {
-    handle.startWatch(poller);
-    handle.unwatch();
 }
 
 template <class T> void PollableQueue<T>::start() {
@@ -112,11 +117,10 @@ template <class T> void PollableQueue<T>::start() {
     if (!stopped) return;
     stopped = false;
     if (!queue.empty()) condition.set();
-    handle.rewatch();
+    condition.rearm();
 }
 
 template <class T> PollableQueue<T>::~PollableQueue() {
-    handle.stopWatch();
 }
 
 template <class T> void PollableQueue<T>::push(const T& t) {
@@ -125,15 +129,15 @@ template <class T> void PollableQueue<T>::push(const T& t) {
     queue.push_back(t);
 }
 
-template <class T> void PollableQueue<T>::dispatch(sys::DispatchHandle& h) {
+template <class T> void PollableQueue<T>::dispatch(PollableCondition& cond) {
     ScopedLock l(lock);
     assert(dispatcher.id() == 0);
     dispatcher = Thread::current();
     process();
     dispatcher = Thread();
-    if (queue.empty()) condition.clear();
+    if (queue.empty()) cond.clear();
     if (stopped) lock.notifyAll();
-    else h.rewatch();
+    else cond.rearm();
 }
 
 template <class T> void PollableQueue<T>::process() {
@@ -159,7 +163,7 @@ template <class T> void PollableQueue<T>::shutdown() {
 template <class T> void PollableQueue<T>::stop() {
     ScopedLock l(lock);
     if (stopped) return;
-    handle.unwatch();
+    condition.disarm();
     stopped = true;
     // Avoid deadlock if stop is called from the dispatch thread
     while (dispatcher.id() && dispatcher.id() != Thread::current().id())
diff --git a/qpid/cpp/src/qpid/sys/posix/PollableCondition.cpp b/qpid/cpp/src/qpid/sys/posix/PollableCondition.cpp
index 0c55fd3c0d..0991e5fd76 100644
--- a/qpid/cpp/src/qpid/sys/posix/PollableCondition.cpp
+++ b/qpid/cpp/src/qpid/sys/posix/PollableCondition.cpp
@@ -22,17 +22,46 @@
  *
  */
 
-#include "PollableCondition.h"
+#include "qpid/sys/PollableCondition.h"
+#include "qpid/sys/DispatchHandle.h"
+#include "qpid/sys/IOHandle.h"
 #include "qpid/sys/posix/PrivatePosix.h"
 #include "qpid/Exception.h"
 
+#include <boost/bind.hpp>
+
 #include <unistd.h>
 #include <fcntl.h>
 
 namespace qpid {
 namespace sys {
 
-PollableCondition::PollableCondition() : IOHandle(new sys::IOHandlePrivate) {
+class PollableConditionPrivate : public sys::IOHandle {
+    friend class PollableCondition;
+
+private:
+    PollableConditionPrivate(const sys::PollableCondition::Callback& cb,
+                             sys::PollableCondition& parent,
+                             const boost::shared_ptr<sys::Poller>& poller);
+    ~PollableConditionPrivate();
+
+    void dispatch(sys::DispatchHandle& h);
+    void rewatch();
+    void unwatch();
+
+private:
+    PollableCondition::Callback cb;
+    PollableCondition& parent;
+    boost::shared_ptr<sys::Poller> poller;
+    int writeFd;
+    std::auto_ptr<DispatchHandleRef> handle;
+};
+
+PollableConditionPrivate::PollableConditionPrivate(const sys::PollableCondition::Callback& cb,
+                                                   sys::PollableCondition& parent,
+                                                   const boost::shared_ptr<sys::Poller>& poller)
+  : IOHandle(new sys::IOHandlePrivate), cb(cb), parent(parent)
+{
     int fds[2];
     if (::pipe(fds) == -1)
         throw ErrnoException(QPID_MSG("Can't create PollableCondition"));
@@ -42,22 +71,71 @@ PollableCondition::PollableCondition() : IOHandle(new sys::IOHandlePrivate) {
         throw ErrnoException(QPID_MSG("Can't create PollableCondition"));
     if (::fcntl(writeFd, F_SETFL, O_NONBLOCK) == -1)
         throw ErrnoException(QPID_MSG("Can't create PollableCondition"));
+    handle.reset (new DispatchHandleRef(*this,
+                                        boost::bind(&sys::PollableConditionPrivate::dispatch, this, _1),
+                                        0, 0));
+    handle->startWatch(poller);
+    handle->unwatch();
+}
+
+PollableConditionPrivate::~PollableConditionPrivate()
+{
+    handle->stopWatch();
+    close(writeFd);
+}
+
+void PollableConditionPrivate::dispatch(sys::DispatchHandle& /*h*/)
+{
+    cb(parent);
+}
+
+void PollableConditionPrivate::rewatch()
+{
+    handle->rewatch();
+}
+
+void PollableConditionPrivate::unwatch()
+{
+    handle->unwatch();
+}
+
+  /* PollableCondition */
+
+PollableCondition::PollableCondition(const Callback& cb,
+                                     const boost::shared_ptr<sys::Poller>& poller)
+  : impl(new PollableConditionPrivate(cb, *this, poller))
+{
+}
+
+PollableCondition::~PollableCondition()
+{
+    delete impl;
+}
+
+void PollableCondition::set() {
+    static const char dummy=0;
+    ssize_t n = ::write(impl->writeFd, &dummy, 1);
+    if (n == -1 && errno != EAGAIN)
+        throw ErrnoException("Error setting PollableCondition");
 }
 
 bool PollableCondition::clear() {
     char buf[256];
     ssize_t n;
     bool wasSet = false;
-    while ((n = ::read(impl->fd, buf, sizeof(buf))) > 0) 
+    while ((n = ::read(impl->impl->fd, buf, sizeof(buf))) > 0) 
         wasSet = true;
-    if (n == -1 && errno != EAGAIN) throw ErrnoException(QPID_MSG("Error clearing PollableCondition"));
+    if (n == -1 && errno != EAGAIN)
+        throw ErrnoException(QPID_MSG("Error clearing PollableCondition"));
     return wasSet;
 }
 
-void PollableCondition::set() {
-    static const char dummy=0;
-    ssize_t n = ::write(writeFd, &dummy, 1);
-    if (n == -1 && errno != EAGAIN) throw ErrnoException("Error setting PollableCondition");
+void PollableCondition::disarm() {
+    impl->unwatch();
+}
+
+void PollableCondition::rearm() {
+    impl->rewatch();
 }
 
 
@@ -71,22 +149,35 @@ void PollableCondition::set() {
 namespace qpid {
 namespace sys {
 
-PollableCondition::PollableCondition() : IOHandle(new sys::IOHandlePrivate) {
+PollableConditionPrivate::PollableConditionPrivate(const PollableCondition::Callback& cb,
+                                                   sys::PollableCondition& parent,
+                                                   const boost::shared_ptr<sys::Poller>& poller)
+  : cb(cb), parent(parent), poller(poller),
+    IOHandle(new sys::IOHandlePrivate) {
     impl->fd = ::eventfd(0, 0);
     if (impl->fd < 0) throw ErrnoException("conditionfd() failed");
 }
 
+void PollableCondition::set() {
+    static const uint64_t value=1;
+    ssize_t n = ::write(impl->impl->fd,
+                        reinterpret_cast<const void*>(&value), 8);
+    if (n != 8) throw ErrnoException("write failed on conditionfd");
+}
+
 bool PollableCondition::clear() {
     char buf[8];
-    ssize_t n = ::read(impl->fd, buf, 8);
+    ssize_t n = ::read(impl->impl->fd, buf, 8);
     if (n != 8) throw ErrnoException("read failed on conditionfd");
     return *reinterpret_cast<uint64_t*>(buf);
 }
 
-void PollableCondition::set() {
-    static const uint64_t value=1;
-    ssize_t n = ::write(impl->fd, reinterpret_cast<const void*>(&value), 8);
-    if (n != 8) throw ErrnoException("write failed on conditionfd");
+void PollableCondition::disarm() {
+  // ????
+}
+
+void PollableCondition::rearm() {
+  // ????
 }
     
 #endif
diff --git a/qpid/cpp/src/qpid/sys/posix/PollableCondition.h b/qpid/cpp/src/qpid/sys/posix/PollableCondition.h
deleted file mode 100644
index 4ec277b0ec..0000000000
--- a/qpid/cpp/src/qpid/sys/posix/PollableCondition.h
+++ /dev/null
@@ -1,56 +0,0 @@
-#ifndef QPID_SYS_POSIX_POLLABLECONDITION_H
-#define QPID_SYS_POSIX_POLLABLECONDITION_H
-
-/*
- *
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- * 
- *   http://www.apache.org/licenses/LICENSE-2.0
- * 
- * Unless required by applicable law or agreed to in writing,
- * software distributed under the License is distributed on an
- * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
- * KIND, either express or implied.  See the License for the
- * specific language governing permissions and limitations
- * under the License.
- *
- */
-
-#include "qpid/sys/IOHandle.h"
-
-namespace qpid {
-namespace sys {
-
-/**
- * A pollable condition to integrate in-process conditions with IO
- * conditions in a polling loop.
- *
- * Setting the condition makes it readable for a poller.
- * 
- * Writable/disconnected conditions are undefined and should not be
- * polled for.
- */
-class PollableCondition : public sys::IOHandle {
-  public:
-    PollableCondition();
-
-    /** Set the condition, triggers readable in a poller. */ 
-    void set();
-
-    /** Get the current state of the condition, then clear it.
-     *@return The state of the condition before it was cleared.
-     */
-    bool clear();
-
-  private:
-    int writeFd;
-};
-}} // namespace qpid::sys
-
-#endif  /*!QPID_SYS_POSIX_POLLABLECONDITION_H*/
diff --git a/qpid/cpp/src/tests/QueueEvents.cpp b/qpid/cpp/src/tests/QueueEvents.cpp
index 3e377d04b3..df3c937e33 100644
--- a/qpid/cpp/src/tests/QueueEvents.cpp
+++ b/qpid/cpp/src/tests/QueueEvents.cpp
@@ -27,6 +27,7 @@
 #include "qpid/broker/QueueEvents.h"
 #include "qpid/client/QueueOptions.h"
 #include "qpid/framing/SequenceNumber.h"
+#include "qpid/sys/Dispatcher.h"
 #include <boost/bind.hpp>
 #include <boost/format.hpp>