new sorce file

src/db/dbServiceIOReadNotifyCache.cpp

@@ -0,0 +1,78 @@
+
+#include "epicsMutex.h"
+#include "tsFreeList.h"
+
+#include "cacIO.h"
+#include "cadef.h" // this can be eliminated when the callbacks use the new interface
+#include "db_access.h" // should be eliminated here in the future
+
+#define epicsExportSharedSymbols
+
+#include "db_access_routines.h"
+#include "dbCAC.h"
+
+dbServiceIOReadNotifyCache::dbServiceIOReadNotifyCache () :
+	readNotifyCacheSize ( 0 ), pReadNotifyCache ( 0 )
+{
+}
+
+dbServiceIOReadNotifyCache::~dbServiceIOReadNotifyCache ()
+{
+	delete this->pReadNotifyCache;
+}
+
+void dbServiceIOReadNotifyCache::show ( unsigned level ) const
+{
+    if ( level > 0 ) {
+        printf ( "\tget call back cache location %p, and its size %lu\n", 
+            static_cast <void *> ( this->pReadNotifyCache ), 
+            this->readNotifyCacheSize );
+    }
+}
+
+// extra effort taken here to not hold the lock when caslling the callback
+void dbServiceIOReadNotifyCache::callReadNotify ( struct dbAddr &addr, 
+	unsigned type, unsigned long count, cacReadNotify &notify )
+{
+    epicsAutoMutex locker ( this->mutex );
+
+    unsigned long size = dbr_size_n ( type, count );
+
+    if ( type > INT_MAX ) {
+        notify.exception ( ECA_BADTYPE, 
+            "type code out of range (high side)", 
+            type, count );
+        return;
+    }
+
+    if ( count > static_cast<unsigned>(INT_MAX) || 
+		count > static_cast<unsigned>(addr.no_elements) ) {
+        notify.exception ( ECA_BADCOUNT, 
+            "element count out of range (high side)",
+            type, count);
+        return;
+    }
+
+    if ( this->readNotifyCacheSize < size) {
+        char * pTmp = new char [size];
+        if ( ! pTmp ) {
+            notify.exception ( ECA_ALLOCMEM, 
+                "unable to allocate callback cache",
+                type, count );
+            return;
+        }
+        delete [] this->pReadNotifyCache;
+        this->pReadNotifyCache = pTmp;
+        this->readNotifyCacheSize = size;
+    }
+    int status = db_get_field ( &addr, static_cast <int> ( type ), 
+                    this->pReadNotifyCache, static_cast <int> ( count ), 0 );
+    if ( status ) {
+        notify.exception ( ECA_GETFAIL, 
+            "db_get_field() completed unsuccessfuly",
+            type, count);
+    }
+    else { 
+        notify.completion ( type, count, this->pReadNotifyCache );
+    }
+}