From 9e49e0131f20b40866d0653cef36577ae3bebcde Mon Sep 17 00:00:00 2001
From: Jeff Hill <johill@lanl.gov>
Date: Tue, 14 Jul 2009 22:51:06 +0000
Subject: [PATCH] fix for mantis 348

---
 src/cas/generic/casStrmClient.cc  | 9 ++++++++-
 src/cas/generic/ioBlocked.h       | 6 ++++++
 src/cas/generic/st/casStreamOS.cc | 1 +
 src/cas/generic/st/ioBlocked.cc   | 7 ++-----
 4 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/cas/generic/casStrmClient.cc b/src/cas/generic/casStrmClient.cc
index 3d0f7e411..cc7d4eac4 100644
--- a/src/cas/generic/casStrmClient.cc
+++ b/src/cas/generic/casStrmClient.cc
@@ -116,6 +116,13 @@ caStatus casStrmClient::processMsg ()
 {
     epicsGuard < casClientMutex > guard ( this->mutex );
 	int status = S_cas_success;
+	
+	// protect against service returning s_casApp_success when it
+	// returned S_casApp_postponeAsyncIO before, but no
+	// asyn IO completed since the last attempt
+	if ( this->isBlocked () ) {
+	    return S_casApp_postponeAsyncIO;
+	}
 
     try {
 
@@ -457,7 +464,7 @@ caStatus casStrmClient::readAction ( epicsGuard < casClientMutex > & guard )
 		return this->sendErr ( guard, mp, pChan->getCID(), 
             status, "read access denied" );
 	}
-
+	
     const gdd * pDesc = 0;
 	status = this->read ( pDesc ); 
 	if ( status == S_casApp_success ) {
diff --git a/src/cas/generic/ioBlocked.h b/src/cas/generic/ioBlocked.h
index b2c684123..919f9f2e8 100644
--- a/src/cas/generic/ioBlocked.h
+++ b/src/cas/generic/ioBlocked.h
@@ -36,6 +36,7 @@ friend class ioBlockedList;
 public:
 	ioBlocked ();
 	virtual ~ioBlocked ();
+    bool isBlocked ();
 private:
 	class ioBlockedList * pList;
 	virtual void ioBlockedSignal ();
@@ -52,5 +53,10 @@ public:
 	ioBlockedList & operator = ( const ioBlockedList & );
 };
 
+inline bool ioBlocked :: isBlocked ()
+{
+    return this->pList != NULL;
+}
+
 #endif // ioBlockedh
  
diff --git a/src/cas/generic/st/casStreamOS.cc b/src/cas/generic/st/casStreamOS.cc
index 3a142327a..d5a74d09e 100644
--- a/src/cas/generic/st/casStreamOS.cc
+++ b/src/cas/generic/st/casStreamOS.cc
@@ -217,6 +217,7 @@ void casStreamIOWakeup::show ( unsigned level ) const
 //
 epicsTimerNotify::expireStatus casStreamIOWakeup::expire ( const epicsTime & /* currentTime */ )
 {
+    assert ( this->pOS );
     casStreamOS	& tmpOS = *this->pOS;
     this->pOS = 0;
 	tmpOS.processInput();
diff --git a/src/cas/generic/st/ioBlocked.cc b/src/cas/generic/st/ioBlocked.cc
index d3b93ae60..1dc8fa499 100644
--- a/src/cas/generic/st/ioBlocked.cc
+++ b/src/cas/generic/st/ioBlocked.cc
@@ -69,9 +69,7 @@ ioBlockedList::ioBlockedList ()
 //
 ioBlockedList::~ioBlockedList ()
 {
-    ioBlocked *pB;
-    
-    while ( (pB = this->get ()) ) {
+    for ( ioBlocked * pB = this->get (); pB; pB = this->get () ) {
         pB->pList = NULL;
     }
 }
@@ -86,14 +84,13 @@ ioBlockedList::~ioBlockedList ()
 void ioBlockedList::signal ()
 {
     tsDLList<ioBlocked> tmp;
-    ioBlocked *pB;
     
     //
     // move all of the items onto tmp
     //
     tmp.add(*this);
     
-    while ( (pB = tmp.get ()) ) {
+    for ( ioBlocked * pB = tmp.get (); pB; pB = tmp.get () ) {
         pB->pList = NULL;
         pB->ioBlockedSignal ();
     }