Modified the FitsOps:ValidFitsFile not to open the specified fits file for...

Modified the FitsOps:ValidFitsFile not to open the specified fits file for validity testing as failures caused memory leaks
	Modified the FitsOps:ValidFitsFile not to open the specified
        fits file for validity testing as failures caused memory leaks

FitsOps.tcl

@@ -21,23 +21,36 @@
 # Returns 0 if invalid (0= false)
 #         1 if valid   (1= true)
 #
-proc FitsOps:ValidFitsFile {filename} {
+proc FitsOps:ValidFitsFile {filename {time_stamp_check 1}} {
 
-    # first check if file exists
-    if {![file exists $filename]} {
-	return 0
-    }
-	
-    # now check if opening file (in read mode) results in error
-    set err_flag [catch {set fob [fits open $filename 0]}]
+   set ret [ChkFile $filename]
+
+   if {$ret==0 || !$time_stamp_check } {return $ret}
+   
+   # --------------------------
+   # Now make a time step check
+   # --------------------------
+   
+   # Calculate the age in seconds since this file was last modified
+   set age_in_secs [expr [clock seconds] - [ file mtime $filename ]]
+
+   # Check that it has been at least 3 seconds since this file was last
+   # modified
+   if {$age_in_secs<3} {return 0}
+
+   # Everything is good so return 1.
+   return 1
 
-    if {$err_flag} {
-	return 0
-    } else {
-	$fob close
-	return 1
-    }
 }
+proc ChkFile {file} {
+
+   if {![file exists $file]}   {return 0}
+   if {![file readable $file]} {return 0}
+   if {[file extension $file]!=".fits"} {return 0}
+    
+   return 1  
+   
+}   
 
 #******************************************************************************
 #
@@ -762,7 +775,10 @@ proc FitsOps:FluxEx {fitsfile outfile} {
 proc FitsOps:ListExtensions {fitsfile} {
 	
     # open file
-    set fob [fits open $fitsfile 0]  ;# read only
+    set err_flag [catch {
+       set fob [fits open $fitsfile 0]  ;# read only
+    }]
+    if {$err_flag} {puts "e1";catch {$fob close}; return ""}
 
     # go through each HDU
     set n_hdu [$fob info nhdu]
@@ -770,8 +786,11 @@ proc FitsOps:ListExtensions {fitsfile} {
     for {set idx 1} {$idx<=$n_hdu} {incr idx 1} {
 	
 	# make this CHDU
-	$fob move $idx
-	
+        set err_flag [catch {
+ 	    $fob move $idx
+	}]
+        if {$err_flag} {puts "e2"; catch {$fob close}; return ""}
+        
 	# Get keyword definition list for EXTNAME
 	# Some 2dfdr old combined files don't have EXTNAME for primary HDU
 	# If error assume keyword does not exist and skip this HDU
@@ -1001,8 +1020,20 @@ proc FitsOps:TableDump {fitsfile tablename arrayname} {
 	
     upvar $arrayname dataA
 
+    # Open the fits file, but in the event of an error
+    # return some dummy values
     set fob [fits open $fitsfile 0]  ;# read only
-	
+   
+    set err_flag {
+        puts "Table Dump error ${err_msg}"
+        set col_names "?"
+        set dataA(col_names) $col_names
+        set dataA(n_cols) 1
+        set dataA(n_rows) 1
+        set dataA(1,1) "???"
+        return $col_names
+    }
+        
     # find HDU with extension name that matches table name
     set hdu [FitsFobOps:FindExtensionHDU $fob $tablename]
     if {$hdu==-1} {