Merge pull request #144 from gnustep/fix-nsvaluetransformer-recursion

Fix deadlock on recursive creation of NSValueTransformer

ChangeLog

@@ -1,3 +1,10 @@
+2020-06-11  Frederik Seiffert <frederik@algoriddim.com>
+
+	* Source/NSValueTransformer.m:
+	Fix recursive creation of value transformers.
+	* Tests/base/NSValueTransformer/basic.m:
+	Add tests for NSValueTransformer.
+
 2020-06-06  Frederik Seiffert <frederik@algoriddim.com>
 
 	* Source/NSBundle.m: Extend NSBundle resources support to handle

Source/NSValueTransformer.m

@@ -52,7 +52,7 @@
 // non-abstract methods
 
 static NSMutableDictionary *registry = nil;
-static NSLock *lock = nil;
+static NSRecursiveLock *lock = nil;
 
 + (void) initialize
 {
@@ -60,7 +60,7 @@ static NSLock *lock = nil;
     {
       NSValueTransformer	*t;
 
-      lock = [NSLock new];
+      lock = [NSRecursiveLock new];
       [[NSObject leakAt: &lock] release];
       registry = [[NSMutableDictionary alloc] init];
       [[NSObject leakAt: &registry] release];

Tests/base/NSValueTransformer/basic.m

@@ -0,0 +1,99 @@
+#import "ObjectTesting.h"
+#import <Foundation/NSAutoreleasePool.h>
+#import <Foundation/NSValueTransformer.h>
+#import <Foundation/NSValue.h>
+
+@interface YesTransformer : NSValueTransformer
+@end
+
+@implementation YesTransformer
+
++ (BOOL) allowsReverseTransformation
+{
+  return NO;
+}
+
++ (Class) transformedValueClass
+{
+  return [NSNumber class];
+}
+
+- (id) transformedValue: (id)value
+{
+  return [NSNumber numberWithBool: YES];
+}
+
+@end
+
+@interface NestedTransformer : NSValueTransformer
+{
+  NSValueTransformer *_backingTransformer;
+}
+@end
+
+@implementation NestedTransformer
+
+- (id) init
+{
+  if (self = [super init]) {
+    _backingTransformer = RETAIN([NSValueTransformer valueTransformerForName:
+      NSStringFromClass([YesTransformer class])]);
+  }
+
+  return self;
+}
+
+- (void) dealloc
+{
+  RELEASE(_backingTransformer);
+  DEALLOC
+}
+
++ (BOOL) allowsReverseTransformation
+{
+  return NO;
+}
+
++ (Class) transformedValueClass
+{
+  return [YesTransformer transformedValueClass];
+}
+
+- (id) transformedValue: (id)value
+{
+  return [_backingTransformer transformedValue: value];
+}
+
+@end
+
+int main()
+{
+  NSAutoreleasePool   *arp = [NSAutoreleasePool new];
+  NSValueTransformer  *transformer;
+  
+  transformer = [NSValueTransformer valueTransformerForName:NSNegateBooleanTransformerName];
+  PASS([[transformer transformedValue:[NSNumber numberWithBool:NO]] boolValue] == YES
+    && [[transformer transformedValue:[NSNumber numberWithBool:YES]] boolValue] == NO,
+    "NSNegateBooleanTransformer transforms correctly");
+  PASS([[transformer reverseTransformedValue:[NSNumber numberWithBool:NO]] boolValue] == YES
+    && [[transformer reverseTransformedValue:[NSNumber numberWithBool:YES]] boolValue] == NO,
+    "NSNegateBooleanTransformer reverse transforms correctly");
+  
+  transformer = [NSValueTransformer valueTransformerForName:NSIsNilTransformerName];
+  PASS([[transformer transformedValue:nil] boolValue] == YES
+    && [[transformer transformedValue:@""] boolValue] == NO,
+    "NSIsNilTransformer transforms correctly");
+  
+  transformer = [NSValueTransformer valueTransformerForName:NSIsNotNilTransformerName];
+  PASS([[transformer transformedValue:@""] boolValue] == YES
+    && [[transformer transformedValue:nil] boolValue] == NO,
+    "NSIsNotNilTransformer transforms correctly");
+  
+  transformer = [NSValueTransformer valueTransformerForName:NSStringFromClass([NestedTransformer class])];
+  PASS([[transformer transformedValue:nil] boolValue] == YES
+    && [[transformer transformedValue:@""] boolValue] == YES,
+    "Custom transformer transforms correctly");
+
+  [arp release]; arp = nil;
+  return 0;
+}