3 files changed, 234 insertions, 0 deletions
diff --git a/cpp/src/qpid/sys/MemoryMappedFile.h b/cpp/src/qpid/sys/MemoryMappedFile.h
new file mode 100644
index 0000000000..3dabada06b
--- /dev/null
+++ b/cpp/src/qpid/sys/MemoryMappedFile.h
@@ -0,0 +1,74 @@
+#ifndef QPID_SYS_MEMORYMAPPEDFILE_H
+#define QPID_SYS_MEMORYMAPPEDFILE_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 <memory>
+#include <string>
+
+namespace qpid {
+namespace sys {
+
+class MemoryMappedFilePrivate;
+/**
+ * Abstraction of memory mapping functionality
+ */
+class MemoryMappedFile {
+  public:
+    MemoryMappedFile();
+    /**
+     * Opens a file that can be mapped by region into memory
+     */
+    std::string open(const std::string& name, const std::string& directory);
+    /**
+     * Returns the page size
+     */
+    size_t getPageSize();
+    /**
+     * Load a portion of the file into memory
+     */
+    char* map(size_t offset, size_t size);
+    /**
+     * Evict a portion of the file from memory
+     */
+    void unmap(char* region, size_t size);
+    /**
+     * Flush any changes to a previously mapped region of the file
+     * back to disk
+     */
+    void flush(char* region, size_t size);
+    /**
+     * Expand the capacity of the file
+     */
+    void expand(size_t offset);
+    /**
+     * Returns true if memory mapping is supported, false otherwise
+     */
+    static bool isSupported();
+  private:
+    std::auto_ptr<MemoryMappedFilePrivate> state;
+
+    MemoryMappedFile(const MemoryMappedFile&);
+    MemoryMappedFile& operator=(const MemoryMappedFile&);
+};
+}} // namespace qpid::sys
+
+#endif  /*!QPID_SYS_MEMORYMAPPEDFILE_H*/
diff --git a/cpp/src/qpid/sys/posix/MemoryMappedFile.cpp b/cpp/src/qpid/sys/posix/MemoryMappedFile.cpp
new file mode 100644
index 0000000000..eae23cc6a9
--- /dev/null
+++ b/cpp/src/qpid/sys/posix/MemoryMappedFile.cpp
@@ -0,0 +1,105 @@
+/*
+ *
+ * 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/MemoryMappedFile.h"
+#include "qpid/Exception.h"
+#include "qpid/Msg.h"
+#include <sys/mman.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+namespace qpid {
+namespace sys {
+namespace {
+const std::string PATH_SEPARATOR("/");
+const std::string ESCAPE("%");
+const std::string VALID("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-.");
+std::string getFileName(const std::string& name, const std::string& dir)
+{
+    std::stringstream filename;
+    if (dir.size())  filename << dir << PATH_SEPARATOR;
+    size_t start = 0;
+    while (true) {
+        size_t i = name.find_first_not_of(VALID, start);
+        if (i == std::string::npos) {
+            filename << name.substr(start);
+            return filename.str();
+        } else {
+            if (i > start) filename << name.substr(start, i-start);
+            filename << ESCAPE << (int) name.at(i);
+            start = i+1;
+        }
+    }
+
+}
+}
+
+class MemoryMappedFilePrivate
+{
+    friend class MemoryMappedFile;
+    const int fd;
+    MemoryMappedFilePrivate(int fd_) : fd(fd_) {}
+};
+MemoryMappedFile::MemoryMappedFile() {}
+
+std::string MemoryMappedFile::open(const std::string& name, const std::string& directory)
+{
+    std::string path = getFileName(name, directory);
+
+    int flags = O_CREAT | O_TRUNC | O_RDWR;
+    int fd = ::open(path.c_str(), flags, S_IRWXU);
+    if (fd == -1) throw qpid::Exception(QPID_MSG("Failed to open memory mapped file " << path << ": " << qpid::sys::strError(errno) << " [flags=" << flags << "]"));
+    state = std::auto_ptr<MemoryMappedFilePrivate>(new MemoryMappedFilePrivate(fd));
+    return path;
+}
+size_t MemoryMappedFile::getPageSize()
+{
+    return ::sysconf(_SC_PAGE_SIZE);
+}
+char* MemoryMappedFile::map(size_t offset, size_t size)
+{
+    int protection = PROT_READ | PROT_WRITE;
+    char* region = (char*) ::mmap(0, size, protection, MAP_SHARED, state->fd, offset);
+    if (region == MAP_FAILED) {
+        throw qpid::Exception(QPID_MSG("Failed to map page into memory: " << qpid::sys::strError(errno)));
+    }
+    return region;
+
+}
+void MemoryMappedFile::unmap(char* region, size_t size)
+{
+    ::munmap(region, size);
+}
+void MemoryMappedFile::flush(char* region, size_t size)
+{
+    ::msync(region, size, MS_ASYNC);
+}
+void MemoryMappedFile::expand(size_t offset)
+{
+    if ((::lseek(state->fd, offset - 1, SEEK_SET) == -1) || (::write(state->fd, "", 1) == -1)) {
+        throw qpid::Exception(QPID_MSG("Failed to expand paged queue file: " << qpid::sys::strError(errno)));
+    }
+}
+bool MemoryMappedFile::isSupported()
+{
+    return true;
+}
+
+}} // namespace qpid::sys
diff --git a/cpp/src/qpid/sys/windows/MemoryMappedFile.cpp b/cpp/src/qpid/sys/windows/MemoryMappedFile.cpp
new file mode 100644
index 0000000000..c43a50db74
--- /dev/null
+++ b/cpp/src/qpid/sys/windows/MemoryMappedFile.cpp
@@ -0,0 +1,55 @@
+/*
+ *
+ * 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/MemoryMappedFile.h"
+
+namespace qpid {
+namespace sys {
+class MemoryMappedFilePrivate {};
+
+MemoryMappedFile::MemoryMappedFile() {}
+
+std::string MemoryMappedFile::open(const std::string& /*name*/, const std::string& /*directory*/)
+{
+    return std::string();
+}
+size_t MemoryMappedFile::getPageSize()
+{
+    return 0;
+}
+char* MemoryMappedFile::map(size_t /*offset*/, size_t /*size*/)
+{
+    return 0;
+}
+void MemoryMappedFile::unmap(char* /*region*/, size_t /*size*/)
+{
+}
+void MemoryMappedFile::flush(char* /*region*/, size_t /*size*/)
+{
+}
+void MemoryMappedFile::expand(size_t /*offset*/)
+{
+}
+bool MemoryMappedFile::isSupported()
+{
+    return false;
+}
+
+}} // namespace qpid::sys