From ddd6826b161e2bb7735b152c15c9ba9bab79aa29 Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Thu, 23 Feb 2012 10:41:20 +0100
Subject: Remove deadlock in session store.

---
 server/src/session.cc | 41 ++++++++++++++++++++++++++++++++++++++---
 server/src/session.h  |  1 +
 2 files changed, 39 insertions(+), 3 deletions(-)

(limited to 'server')

diff --git a/server/src/session.cc b/server/src/session.cc
index 234f004..6bb4440 100644
--- a/server/src/session.cc
+++ b/server/src/session.cc
@@ -82,10 +82,20 @@ std::string Session::id()
 void Session::lock()
 {
   mutex.lock();
+  DEBUG(session, "lock() %p (%s)\n", this, sessionid.c_str());
+}
+
+bool Session::trylock()
+{
+  bool r = mutex.trylock();
+  DEBUG(session, "trylock() %p (%s) == %s\n",
+        this, sessionid.c_str(), r?"true":"false");
+  return r;
 }
 
 void Session::unlock()
 {
+  DEBUG(session, "unlock() %p (%s)\n", this, sessionid.c_str());
   mutex.unlock();
 }
 
@@ -299,17 +309,41 @@ size_t Sessions::size()
 
 void Sessions::store()
 {
+  Session *session = NULL;
+  std::string sessionid;
+  do {
+    session = NULL;
+    {
+      MutexAutolock lock(mutex);
+      std::map<std::string, Session*>::iterator head = sessions.begin();
+      if(head != sessions.end()) {
+        session = head->second;
+        sessionid = head->first;
+        if(session->trylock()) sessions.erase(sessionid);
+        else continue;
+      }
+    }
+    if(session != NULL) {
+      SessionSerialiser ser(env, Conf::session_path);
+      ser.save(session);
+      delete session;
+    }
+  } while(session != NULL);
+
+  /*
   MutexAutolock lock(mutex);
 
   std::map<std::string, Session*>::iterator i = sessions.begin();
   while(i != sessions.end()) {
     SessionSerialiser ser(env, Conf::session_path);
-    ser.save(i->second);
-    delete i->second;
-    sessions.erase(i);
+    Session *s = i->second;
+    s->lock();
+    ser.save(s);
+    delete s;
     i++;
   }
   sessions.clear();
+  */
 }
 
 std::vector<std::string> Sessions::activeSessions()
@@ -335,6 +369,7 @@ SessionAutounlock::SessionAutounlock(Session **s)
 
 SessionAutounlock::~SessionAutounlock()
 {
+  DEBUG(session, "SessionAutounlock(%p)\n", *session);
   if(*session) (*session)->unlock();
 }
 
diff --git a/server/src/session.h b/server/src/session.h
index 85382f5..9ad84b5 100644
--- a/server/src/session.h
+++ b/server/src/session.h
@@ -53,6 +53,7 @@ public:
   std::string id();
   
   void lock();
+  bool trylock();
   void unlock();
 
   void commit() throw(LUAScript::Exception, Journal::Exception);
-- 
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