Don't create the SHM session mapping until something tries to use it

1 files changed, 18 insertions, 7 deletions

diff --git a/project2/sessionShm.cpp b/project2/sessionShm.cpp
index e4c9d16..8064142 100644
--- a/project2/sessionShm.cpp
+++ b/project2/sessionShm.cpp
@@ -24,13 +24,14 @@ class SessionShmData {
 		SessionValues svs;
 		time_t expiryTime;
 
-		static boost::interprocess::managed_mapped_file shm;
+		static boost::interprocess::managed_mapped_file & shm();
+		static boost::shared_ptr<boost::interprocess::managed_mapped_file> _shm;
 		friend class SessionContainerShm;
 };
 
 const char * shmFile = "/tmp/project2.sessions";
 
-boost::interprocess::managed_mapped_file SessionShmData::shm(open_or_create, shmFile, 1024 * 1024);
+boost::shared_ptr<boost::interprocess::managed_mapped_file> SessionShmData::_shm;
 
 SessionContainerShm::SessionContainerShm()
 {
@@ -44,8 +45,8 @@ void
 SessionContainerShm::CleanUp()
 {
 	std::set<std::string> toDelete;
-	for (managed_mapped_file::const_named_iterator i = SessionShmData::shm.named_begin();
-			i != SessionShmData::shm.named_end(); i++) {
+	for (managed_mapped_file::const_named_iterator i = SessionShmData::shm().named_begin();
+			i != SessionShmData::shm().named_end(); i++) {
 		const SessionShmData * s = static_cast<const SessionShmData *>(i->value());
 		if (s) {
 			if (s->expiryTime < time(NULL)) {
@@ -54,7 +55,7 @@ SessionContainerShm::CleanUp()
 		}
 	}
 	for(std::set<std::string>::const_iterator s = toDelete.begin(); s != toDelete.end(); s++) {
-		SessionShmData::shm.destroy<const SessionShmData>(s->c_str());
+		SessionShmData::shm().destroy<const SessionShmData>(s->c_str());
 	}
 }
 
@@ -65,7 +66,7 @@ SessionContainerShm::getSession(boost::uuids::uuid & sid)
 		sid = boost::uuids::random_generator()();
 	}
 	return SessionPtr(new SessionShm(
-			SessionShmData::shm.find_or_construct<SessionShmData>(boost::lexical_cast<std::string>(sid).c_str())()));
+			SessionShmData::shm().find_or_construct<SessionShmData>(boost::lexical_cast<std::string>(sid).c_str())()));
 }
 
 SessionShm::SessionShm(SessionShmData * d) : data(d)
@@ -89,7 +90,7 @@ SessionShm::ExpiryTime() const
 }
 
 SessionShmData::SessionShmData() :
-	svs(std::less<SKey>(), AllocatorValueType(shm.get_segment_manager()))
+	svs(std::less<SKey>(), AllocatorValueType(shm().get_segment_manager()))
 {
 }
 
@@ -97,6 +98,16 @@ SessionShmData::~SessionShmData()
 {
 }
 
+boost::interprocess::managed_mapped_file &
+SessionShmData::shm()
+{
+	if (!_shm) {
+		_shm = boost::shared_ptr<boost::interprocess::managed_mapped_file>(
+				new boost::interprocess::managed_mapped_file(open_or_create, shmFile, 1024 * 1024));
+	}
+	return *_shm;
+}
+
 Glib::ustring
 SessionShm::GetValue(const Glib::ustring & name) const
 {