Moved PollableCondition into sys/posix, posix only impl.

git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@694812 13f79535-47bb-0310-9956-ffa450edef68

2 files changed, 156 insertions, 0 deletions

diff --git a/cpp/src/qpid/sys/posix/PollableCondition.cpp b/cpp/src/qpid/sys/posix/PollableCondition.cpp
new file mode 100644
index 0000000000..4ff66d1106
--- /dev/null
+++ b/cpp/src/qpid/sys/posix/PollableCondition.cpp
@@ -0,0 +1,100 @@
+#ifndef QPID_SYS_LINUX_POLLABLECONDITION_CPP
+#define QPID_SYS_LINUX_POLLABLECONDITION_CPP
+
+/*
+ *
+ * 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.
+ *
+ */
+
+// FIXME aconway 2008-08-11: this could be of more general interest,
+// move to common lib.
+// 
+
+#include "PollableCondition.h"
+#include "qpid/sys/posix/PrivatePosix.h"
+#include "qpid/Exception.h"
+
+#include <unistd.h>
+#include <fcntl.h>
+
+namespace qpid {
+namespace sys {
+
+PollableCondition::PollableCondition() : IOHandle(new sys::IOHandlePrivate) {
+    int fds[2];
+    if (::pipe(fds) == -1)
+        throw ErrnoException(QPID_MSG("Can't create PollableCondition"));
+    impl->fd = fds[0];
+    writeFd = fds[1];
+    if (::fcntl(impl->fd, F_SETFL, O_NONBLOCK) == -1)
+        throw ErrnoException(QPID_MSG("Can't create PollableCondition"));
+    if (::fcntl(writeFd, F_SETFL, O_NONBLOCK) == -1)
+        throw ErrnoException(QPID_MSG("Can't create PollableCondition"));
+}
+
+bool PollableCondition::clear() {
+    char buf[256];
+    ssize_t n;
+    bool wasSet = false;
+    while ((n = ::read(impl->fd, buf, sizeof(buf))) > 0) 
+        wasSet = true;
+    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");
+}
+
+
+#if 0
+// FIXME aconway 2008-08-12: More efficient Linux implementation using
+// eventfd system call.  Move to separate file & do configure.ac test
+// to enable this when ::eventfd() is available.
+
+#include <sys/eventfd.h>
+
+namespace qpid {
+namespace sys {
+
+PollableCondition::PollableCondition() : IOHandle(new sys::IOHandlePrivate) {
+    impl->fd = ::eventfd(0, 0);
+    if (impl->fd < 0) throw ErrnoException("conditionfd() failed");
+}
+
+bool PollableCondition::clear() {
+    char buf[8];
+    ssize_t n = ::read(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");
+}
+    
+#endif
+
+}} // namespace qpid::sys
+
+#endif  /*!QPID_SYS_LINUX_POLLABLECONDITION_CPP*/
diff --git a/cpp/src/qpid/sys/posix/PollableCondition.h b/cpp/src/qpid/sys/posix/PollableCondition.h
new file mode 100644
index 0000000000..4ec277b0ec
--- /dev/null
+++ b/cpp/src/qpid/sys/posix/PollableCondition.h
@@ -0,0 +1,56 @@
+#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*/