Add -isNull

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/sqlclient/trunk@39698 72102866-910b-0410-8b05-ffd578937521

ChangeLog

@@ -1,3 +1,10 @@
+2016-04-27 Richard Frith-Macdonald  <rfm@gnu.org>
+
+	* SQLClient.h:
+	* SQLClient.m:
+	Add -isNull helper method for testing for null fields in records
+	returned from the database.
+
 2016-02-18 Richard Frith-Macdonald  <rfm@gnu.org>
 
 	* configure.ac: get host and cpu with more recent gnustep-make

SQLClient.h

@@ -208,6 +208,17 @@ extern NSString * const SQLClientDidDisconnectNotification;
 #define SQLCLIENT_PRIVATE       @private
 #endif
 
+/** This category is to extend NSObject with SQL oriented helper methods.
+ */
+@interface      NSObject(SQLClient)
+
+/** Trivial method to test a field in a record returned from the database
+ * to see if it is a NULL.  This is equivalent to<br />
+ * (receiver == [NSNull null] ? YES : NO)<br />
+ */
+- (BOOL) isNull;
+@end
+
 /** This class is used to hold key information for a set of SQLRecord
  * objects produced by a single query.
  */

SQLClient.m

@@ -217,7 +217,7 @@ static Class rClass = 0;
 + (void) initialize
 {
   GSTickerTimeNow();
-  if (null == nil)
+  if (nil == null)
     {
       null = [NSNull new];
       aClass = [NSMutableArray class];
@@ -917,6 +917,10 @@ static int	        poolConnections = 0;
     {
       static id	modes[1];
       
+      if (nil == null)
+        {
+          null = [NSNull new];
+        }
       SQLClientClass = self;
       modes[0] = NSDefaultRunLoopMode;
       queryModes = [[NSArray alloc] initWithObjects: modes count: 1];
@@ -4125,3 +4129,14 @@ validName(NSString *name)
 
 @end
 
+@implementation NSObject (SQLClient)
+- (BOOL) isNull
+{
+  if (nil == null)
+    {
+      null = [NSNull new];
+    }
+  return (self == null ? YES : NO);
+}
+@end
+