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IvarDescription.xcodeproj
IvarDescription.xcodeproj
 
 
IvarDescription
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Foundation_IvarDescription

Backporting NSObject(IvarDescription) category which is bundled in UIKit. Written in Objective-C++ with supporting ARC/MRC.

Motivation

UIKit provides debugging methods in NSObject(IvarDescription) category internally:

@interface NSObject (IvarDescription)
- (id)_shortMethodDescription;
- (id)_methodDescription;
- (id)__methodDescriptionForClass:(Class)arg1;
- (id)_propertyDescription;
- (id)__propertyDescriptionForClass:(Class)arg1;
- (id)_ivarDescription;
- (id)__ivarDescriptionForClass:(Class)arg1;
@end

Briefly speaking: I'll explain about -[NSObject(IvarDescription) _shortMethodDescription]. Let's define the sample object like below:

@interface TestObject : NSObject <NSStreamDelegate>
@property (class, weak) id<NSStreamDelegate> delegate;
@property (copy) NSNumber *number;
@property (assign, getter=isEnabled) BOOL enabled;
+ (oneway void)foo;
- (id)foo:(NSUInteger *)foo name:(NSString *)name error:(NSError * __autoreleasing * _Nullable)error;
@end

Here's the result of [TestObject _shortMethodDescription]. It dumps all property and method declarations, including all private declarations. Also it gives address of IMP - it is useful when you are setting breakpoints based on address or dumping assembly.

(lldb) expression -l objc -O -- [TestObject _shortMethodDescription]
<TestObject: 0x102619a10>:
in TestObject:
    Class Methods:
        + (void) foo; (0x1026114ac)
    Properties:
        @property (copy) NSNumber* number;  (@synthesize number = _number;)
        @property (getter=isEnabled) BOOL enabled;  (@synthesize enabled = _enabled;)
        @property (readonly) unsigned long hash;
        @property (readonly) Class superclass;
        @property (readonly, copy) NSString* description;
        @property (readonly, copy) NSString* debugDescription;
    Instance Methods:
        - (id) foo:(unsigned long*)arg1 name:(id)arg2 error:(id*)arg3; (0x1026114c0)
        - (id) number; (0x102611520)
        - (void) setNumber:(id)arg1; (0x102611548)
        - (BOOL) isEnabled; (0x102611580)
        - (void) setEnabled:(BOOL)arg1; (0x1026115a0)
        - (void) .cxx_destruct; (0x1026115c8)
(NSObject ...)

I've backported NSObject(IvarDescription) from the beginning. I'm not reinventing the wheel. Again, it's bundled in UIKit. If you are handling non-UIKit projects like Cocoa or Linux envrionments, you cannot use these cool tools. To use these I have to backport using Objective-C Runtime.

OK, Enough.

Limitations

  • All specifications of Type Encodings are not supported. (e.g. An array, A union types are not implemented yet.)

  • Objects eligible for GCC are not supported. (It's 2023... is it needed?)

  • Dumping data layouts for struct type is not implemented yet. NSObject(IvarDescription) supports dumping struct type restrictively, but I want to implement perferctly soon. It's theoretically implementable.

Usages

My Foundation_IvarDescriptions provides total 8 methods - dumping methods/properties/ivars descriptions. Also it supports dumping Objective-C Protocols which is not supported in NSObject(IvarDescription)!

@interface NSObject (Foundation_IvarDescription)
- (NSString *)_fd_shortMethodDescription;
- (NSString *)_fd_methodDescription;
- (NSString *)_fd__methodDescriptionForClass:(Class)arg1;
- (NSString *)_fd_propertyDescription;
- (NSString *)_fd__propertyDescriptionForClass:(Class)arg1;
- (NSString *)_fd_ivarDescription;
- (NSString *)_fd__ivarDescriptionForClass:(Class)arg1;
- (NSString *)_fd__protocolDescriptionForProtocol:(Protocol *)arg1;
@end

It's time to dive into Foundation_IvarDescription.

_fd_shortMethodDescription

Backport of -[NSObject(IvarDescription) _shortMethodDescription]. Only dumps class itself, excluding subclasses.

  • Dumping Conformance of Procotols.

  • Dumping Class/Instance Properties.

  • Dumping Class/Instance Methods.

  • Dumping IMP addresses.

(lldb) expression -l objc -O -- [TestObject _fd_shortMethodDescription]
<TestObject: 0x10000c8e0> (NSStreamDelegate):

in TestObject:
    Class Methods:
        + (oneway void) foo; (0x100003028)
    Properties:
        @property (class, weak) <NSStreamDelegate>* delegate;
        @property (copy) NSNumber* number;
        @property (getter=isEnabled) _Bool enabled;
        @property (readonly) unsigned long hash;
        @property (readonly) Class superclass;
        @property (readonly, copy) NSString* description;
        @property (readonly, copy) NSString* debugDescription;
    Instance Methods:
        - (id) foo:(unsigned long*)arg1 name:(id)arg2 error:(id*)arg3; (0x10000303c)
        - (id) number; (0x100003060)
        - (void) setNumber:(id)arg1; (0x100003088)
        - (_Bool) isEnabled; (0x1000030c0)
        - (void) setEnabled:(_Bool)arg1; (0x1000030e0)
(NSObject ...)

_fd_methodDescription

Backport of -[NSObject(IvarDescription) _methodDescription]. It dumps descriptions of class itself and subclasses.

  • Dumping Conformance of Procotols.

  • Dumping Class/Instance Properties.

  • Dumping Class/Instance Methods.

  • Dumping IMP addresses.

(lldb) expression -l objc -O -- [TestObject _fd_methodDescription]
<TestObject: 0x10000c8e0> (NSStreamDelegate):

in TestObject:
    Class Methods:
        + (oneway void) foo; (0x100003028)
    Properties:
        @property (class, weak) <NSStreamDelegate>* delegate;
        @property (copy) NSNumber* number;
        @property (getter=isEnabled) _Bool enabled;
        @property (readonly) unsigned long hash;
        @property (readonly) Class superclass;
        @property (readonly, copy) NSString* description;
        @property (readonly, copy) NSString* debugDescription;
    Instance Methods:
        - (id) foo:(unsigned long*)arg1 name:(id)arg2 error:(id*)arg3; (0x10000303c)
        - (id) number; (0x100003060)
        - (void) setNumber:(id)arg1; (0x100003088)
        - (_Bool) isEnabled; (0x1000030c0)
        - (void) setEnabled:(_Bool)arg1; (0x1000030e0)
in NSObject:
    Class Methods:
        + (void) load; (0x1a0d4be70)
        + (long) version; (0x1a0d54ae0)
        <omitted...>
    Properties:
        @property (class, readonly) _Bool accessInstanceVariablesDirectly;
        @property (readonly, copy) NSClassDescription* classDescription;
        <omitted...>
    Instance Methods:
        - (Class) classForCoder; (0x1a0d7858c)
        - (id) replacementObjectForCoder:(id)arg1; (0x1a0d67240)
        <omitted...>

_fd__methodDescriptionForClass:

Backport of -[NSObject(IvarDescription) _methodDescriptionForClass:]. It dumps descriptions of input class and subclasses.

  • Dumping Conformance of Procotols.

  • Dumping Class/Instance Properties.

  • Dumping Class/Instance Methods.

  • Dumping IMP addresses.

(lldb) expression -l objc -O -- [NSObject _fd__methodDescriptionForClass:TestObject.class]
<TestObject: 0x10000c8e0> (NSStreamDelegate):

in TestObject:
    Class Methods:
        + (oneway void) foo; (0x100003028)
    Properties:
        @property (class, weak) <NSStreamDelegate>* delegate;
        @property (copy) NSNumber* number;
        @property (getter=isEnabled) _Bool enabled;
        @property (readonly) unsigned long hash;
        @property (readonly) Class superclass;
        @property (readonly, copy) NSString* description;
        @property (readonly, copy) NSString* debugDescription;
    Instance Methods:
        - (id) foo:(unsigned long*)arg1 name:(id)arg2 error:(id*)arg3; (0x10000303c)
        - (id) number; (0x100003060)
        - (void) setNumber:(id)arg1; (0x100003088)
        - (_Bool) isEnabled; (0x1000030c0)
        - (void) setEnabled:(_Bool)arg1; (0x1000030e0)
in NSObject:
    Class Methods:
        + (void) load; (0x1a0d4be70)
        + (long) version; (0x1a0d54ae0)
        <omitted...>
    Properties:
        @property (class, readonly) _Bool accessInstanceVariablesDirectly;
        @property (readonly, copy) NSClassDescription* classDescription;
        <omitted...>
    Instance Methods:
        - (Class) classForCoder; (0x1a0d7858c)
        - (id) replacementObjectForCoder:(id)arg1; (0x1a0d67240)
        <omitted...>

_fd_propertyDescription

Backport of -[NSObject(IvarDescription) _propertyDescription]. It dumps properties of class itself and subclasses.

(lldb) expression -l objc -O -- [TestObject _fd_propertyDescription]
<TestObject: 0x10000c8e8> (NSStreamDelegate):


in TestObject:
    Properties:
        @property (class, weak) <NSStreamDelegate>* delegate;
        @property (copy) NSNumber* number;
        @property (getter=isEnabled) _Bool enabled;
        @property (readonly) unsigned long hash;
        @property (readonly) Class superclass;
        @property (readonly, copy) NSString* description;
        @property (readonly, copy) NSString* debugDescription;

in NSObject:
    Properties:
        @property (class, readonly) _Bool accessInstanceVariablesDirectly;
        @property (readonly, copy) NSClassDescription* classDescription;
        @property (readonly, copy) NSArray* attributeKeys;
        @property (readonly, copy) NSArray* toOneRelationshipKeys;
        @property (readonly, copy) NSArray* toManyRelationshipKeys;
        @property void* observationInfo;
        @property (readonly) Class classForKeyedArchiver;
        @property (readonly, retain) id autoContentAccessingProxy;
        @property (copy) NSDictionary* scriptingProperties;
        @property (readonly) unsigned int classCode;
        @property (readonly, copy) NSString* className;
        @property (readonly) unsigned long hash;
        @property (readonly) Class superclass;
        @property (readonly, copy) NSString* description;
        @property (readonly, copy) NSString* debugDescription;

_fd__propertyDescriptionForClass:

Backport of -[NSObject(IvarDescription) __propertyDescriptionForClass:]. It dumps properties of input class and subclasses.

(lldb) expression -l objc -O -- [NSObject _fd__propertyDescriptionForClass:[TestObject class]]
<TestObject: 0x10000c8e8> (NSStreamDelegate):


in TestObject:
    Properties:
        @property (class, weak) <NSStreamDelegate>* delegate;
        @property (copy) NSNumber* number;
        @property (getter=isEnabled) _Bool enabled;
        @property (readonly) unsigned long hash;
        @property (readonly) Class superclass;
        @property (readonly, copy) NSString* description;
        @property (readonly, copy) NSString* debugDescription;

in NSObject:
    Properties:
        @property (class, readonly) _Bool accessInstanceVariablesDirectly;
        @property (readonly, copy) NSClassDescription* classDescription;
        @property (readonly, copy) NSArray* attributeKeys;
        @property (readonly, copy) NSArray* toOneRelationshipKeys;
        @property (readonly, copy) NSArray* toManyRelationshipKeys;
        @property void* observationInfo;
        @property (readonly) Class classForKeyedArchiver;
        @property (readonly, retain) id autoContentAccessingProxy;
        @property (copy) NSDictionary* scriptingProperties;
        @property (readonly) unsigned int classCode;
        @property (readonly, copy) NSString* className;
        @property (readonly) unsigned long hash;
        @property (readonly) Class superclass;
        @property (readonly, copy) NSString* description;
        @property (readonly, copy) NSString* debugDescription;

_fd_ivarDescription

Backport of -[NSObject(IvarDescription) _fd_ivarDescription]. It dumps ivar descriptions of class itself and subclasses.

(lldb) expression -l objc -O -- [TestObject new]
<TestObject: 0x600000204300>

(lldb) expression -l objc -O -- [0x600000204300 _fd_ivarDescription]
<TestObject: 0x600000204300>:

in TestObject:
    _enabled <0x600000204308> (_Bool): NO
    _number <0x600000204310> (NSNumber*): (null)
in NSObject:
    isa <0x600000204300> (Class): TestObject

_fd__ivarDescriptionForClass:

Backport of -[NSObject(IvarDescription) __ivarDescriptionForClass:]. It dumps ivar descriptions of input class only.

(lldb) expression -l objc -O -- [0x600000204300 _fd__ivarDescriptionForClass:[TestObject class]]
in TestObject:
    _enabled <0x600000204308> (_Bool): NO
    _number <0x600000204310> (NSNumber*): (null)

_fd__protocolDescriptionForProtocol:

It dumps descriptions of input protocol. It cannot distinguish between required and optional methods because of bug of protocol_copyMethodDescriptionList.

  • Dumping Conformance of Procotols.

  • Dumping Class/Instance Properties.

  • Dumping Class/Instance Methods.

Define the sample protocol like below:

@protocol TestProtocol <NSObject, NSTabViewDelegate>
@optional @property (class, retain) id string;
@optional @property NSUInteger number;
@property NSUInteger number2;
- (id)foo;
+ (id)foo:(void)a1 a2:(long long)a2;
- (NSUInteger)foo2:(NSUInteger)a1 a2:(CGRect)a2 a3:(CGSize)a3;
@end

Here's the output of dumping TestProtocol with _fd__protocolDescriptionForProtocol::

<TestProtocol: 0x10000cca8> (NSObject, NSTabViewDelegate) :

in TestProtocol:
    Class Methods:
        + (id) foo:(void)arg1 a2:(long)arg2;
        + (id) string;
        + (void) setString:(id)arg1;
    Properties:
        @property (class, retain) id string;
        @property unsigned long number;
        @property unsigned long number2;
    Instance Methods:
        - (unsigned long) foo2:(unsigned long)arg1 a2:(struct CGRect)arg2 a3:(struct CGSize)arg3;
        - (unsigned long) number2;
        - (void) setNumber2:(unsigned long)arg1;
        - (unsigned long) number;
        - (void) setNumber:(unsigned long)arg1;
        - (id) foo;

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