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using System;
using System.Drawing;
using MonoTouch.ObjCRuntime;
using MonoTouch.Foundation;
using MonoTouch.UIKit;
namespace NSPredicateProblem
{
public partial class NSPredicateProblemViewController : UIViewController
{
static bool UserInterfaceIdiomIsPhone {
get { return UIDevice.CurrentDevice.UserInterfaceIdiom == UIUserInterfaceIdiom.Phone; }
}
public NSPredicateProblemViewController ()
: base (UserInterfaceIdiomIsPhone ? "NSPredicateProblemViewController_iPhone" : "NSPredicateProblemViewController_iPad", null)
{
}
public override void DidReceiveMemoryWarning ()
{
// Releases the view if it doesn't have a superview.
base.DidReceiveMemoryWarning ();
// Release any cached data, images, etc that aren't in use.
}
UILabel counter;
UILabel failedAttemptsLabel;
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
View.AutosizesSubviews = true;
// Perform any additional setup after loading the view, typically from a nib.
counter = new UILabel(new RectangleF(0,20,320,50)) {
Lines = 0
};
this.View.Add(counter);
failedAttemptsLabel = new UILabel(new RectangleF(0,70,320,250)){
Lines = 0,
};
this.View.Add(failedAttemptsLabel);
}
public override void ViewDidAppear (bool animated)
{
base.ViewDidAppear (animated);
InvokeInBackground (() => {
int failedAttemptsNonSingleton = 0;
int failedAttemptsDirect = 0;
int failedAttemptsMethod = 0;
int failedAttemptsMethod2 = 0;
int failedAttemptsNull = 0;
for (long i = 0; i < long.MaxValue; i++) {
System.GC.Collect();
// monotouch is missing support for these two bindings
// + (NSPredicate *)predicateWithFormat:(NSString *)format,, ...
// + (NSPredicate *)predicateWithFormat:(NSString *)format arguments:(va_list)argList
// Should be allowed to pass null to predicateWithFormat
// https://developer.apple.com/library/mac/documentation/Cocoa/Reference/Foundation/Classes/NSPredicate_Class/Reference/NSPredicate.html
NSPredicate predicate = null;
try {
// fails always
// this fails because binding for NSPredicate.FromFormat calls predicateWithFormat:argumentArray:
//NSPredicate.FromFormat("TRUEPREDICATE",null);
// passes always
// IntPtr_IntPtr version of needed binding
// NSPredicate predicate = NSPredicateExtensions.FromFormat("a == %@",new NSString("b"));
predicate = NSPredicate.FromFormat("a == %@", (NSObject) null);
// WORKS
// IntPtr version of needed binding
//NSPredicate predicate = NSPredicateExtensions.FromFormat("TRUEPREDICATE");
}
catch (Exception e) {
failedAttemptsNull++;
}
// Passing Predicate Method - fails
// passing empty NSObject[] array to NSPredicate.FromFormat fails when predicate is passed to
// NSCompoundPredicate. something is looks wrong with retain count
try {
predicate = NSPredicate.FromFormat ("TRUEPREDICATE");
// note: predicate.retainCount is -1
predicate = AppendDeletedPredicate (predicate);
}
catch (Exception e) {
failedAttemptsMethod++;
}
// unrolled NSCompoundPredicate, same as above - doesn't fail
try {
NSPredicate[] predicates = new NSPredicate[]
{
NSPredicate.FromFormat ("FALSEPREDICATE"),
NSPredicate.FromFormat("(markedDeleted == NO)")
};
predicate = new NSCompoundPredicate(NSCompoundPredicateType.And, predicates);
}
catch {
failedAttemptsDirect++;
}
// Passing Predicate Method using correct binding - fails far less but still returns an eroor
// passing empty NSObject[] array to NSPredicate.FromFormat fails when predicate is passed to
// NSCompoundPredicate. something is looks wrong with retain count
try {
predicate = NSPredicate.FromFormat("TRUEPREDICATE");
predicate = AppendDeletedPredicate2 (predicate);
}
catch (Exception e) {
failedAttemptsMethod2++;
}
BeginInvokeOnMainThread (() => {
counter.Text = String.Format ("iteration i:{0} NSPredicate.FromFormat", i);
failedAttemptsLabel.Text = String.Format ("Passing Null to Predicate failed:{0}\rNSCompoundPredicate from method failed:{1}\rNSCompoundPredicate unrolled failed:{2} NSCompoundPredicate w/ correct binding from method failed:{3}",
failedAttemptsNull, failedAttemptsMethod, failedAttemptsDirect, failedAttemptsMethod2);
});
}
});
}
public static NSPredicate AppendDeletedPredicate(NSPredicate predicate)
{
NSPredicate[] predicates = new NSPredicate[]
{
predicate,
NSPredicate.FromFormat("(markedDeleted == NO)")
};
return new NSCompoundPredicate(NSCompoundPredicateType.And, predicates);
}
public static NSPredicate AppendDeletedPredicate2(NSPredicate predicate)
{
NSPredicate[] predicates = new NSPredicate[]
{
predicate,
NSPredicate.FromFormat("(markedDeleted == %@)", NSNull.Null)
};
return new NSCompoundPredicate(NSCompoundPredicateType.And, predicates);
}
}
}
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