Download: http://networkpx.googlecode.com/files/class-dump-z_0.2-0.tar.gz .

• Why a yet another class-dump?
• Why you don't want to use class-dump-z
• Features
• 10x the speed
• Portable
• Correct ivar offsets
• Struct name prettifying
• Stable name generation for anonymous structs
• Properties
• Propertization
• Hide inherited and delegate methods
• Readable argument names
• Correct header generation
• Miscellaneous features
• What's missing
• Sort by inheritance (-I flag), Recursive dumping (-r)

Why a yet another class-dump?

class-dump is a command-line tool to extract Objective-C class interfaces, written by Steve Nygard 17 years ago. The development however paused in 2007 at version 3.1.2, without support for the newest ABI.

This caused the birth of class-dump-x by Holly Lee in 2008. But being a straight modified version of class-dump, it inherited some of the problems, e.g. the ivar offsets are calculated wrongly, properties are not supported, etc.

I, using class-dump-x a lot for reverse engineering, finds that the ivar offset problem is hard to get over with. Having no answers a few months after a bug report, I decided to just fix the problem myself — hence class-dump-z is started.

(While I was creating class-dump-z, the original class-dump development suddenly reactivated at July 1st. The newest version 3.2 does support 2.0 ABI now, but the ivar offset info is even worse than class-dump-x.)

Why you don't want to use class-dump-z

Instead of a generic-purpose class dumper, class-dump-z was written with iPhoneOS development in mind. Therefore, the following features will probably never be implemented:

• 64-bit support. (Unless there is a 4 GiB RAM iPhone.)
• Objective-C 1.0 ABI.

Features

10x the speed

• time class-dump-? -a -A UIKit > /dev/null

class-dump-z is written from scratch using C++ avoiding using dynamic calls, unlike class-dump and class-dump-x which are written in Objective-C. Removing these unnecessary calls makes class-dump-z near 10 times faster than the precedences.

Portable

Since class-dump-z is written in C++, it is very easy to port to other platforms. Currently Mac OS X 10.6, iPhoneOS 3.1, Linux (x86 and amd64) and Windows (≥XP) are officially supported.

Correct ivar offsets

unsigned int _isHighlighted:1; // 68 = 0x44
unsigned int _isSelected:1;    // 69 = 0x45

UITableView *_table;                         // 92 = 0x5c
BOOL _allowsCustomizing;                     // 96 = 0x60
NSArray *_moreViewControllers;               // 97 = 0x61
UIMoreListCellLayoutManager *_layoutManager; // 101 = 0x65

unsigned int _isHighlighted:1;
unsigned int _isSelected:1;

UITableView *_table;
BOOL _allowsCustomizing;
NSArray *_moreViewControllers;
UIMoreListCellLayoutManager *_layoutManager;

unsigned _isHighlighted : 1; // 68 = 0x44
unsigned _isSelected : 1;    // 68 = 0x44

UITableView* _table;                         // 92 = 0x5c
BOOL _allowsCustomizing;                     // 96 = 0x60
NSArray* _moreViewControllers;               // 100 = 0x64
UIMoreListCellLayoutManager* _layoutManager; // 104 = 0x68

Struct name prettifying

• class-dump-? -C UIScrollView -f hitTest UIKit

class-dump-z will typedef structs and unions to the most presentable name with heuristics.

This feature can be explicitly turned off with the -N switch.

Stable name generation for anonymous structs

• class-dump-? -C UIThreePartImageView UIKit

Ever tried to diff a library between two versions? You'll be frustrated by so many differences that are caused by a change of indices in anonymous structs. No more problem in class-dump-z — as long as the struct is having the same members, the generated name will be fixed.

The name is computed by the CRC-32 checksum of the Objective-C type encoding of the struct.

Properties

• class-dump-? -C UIScrollView UIKit

class-dump-z supports declared properties. Not only that, it supports every property attributes, including the undocumented ones. Moreover, it will hide the extra copy of getters/setters if a property is present.

Propertization

Some libraries are written before the dot syntax was introduced or by some dot-syntax-haters, so you'll see a long list of getters/setters like

-(void)setTitle:(id)title;
-(id)title;
-(void)setSubtitle:(id)subtitle;
-(id)subtitle;
...

I found it pretty annoying. In class-dump-z you can supply the -p switch to automatically convert them into

@property(retain) id title;
@property(retain) id subtitle;
...

Hide inherited and delegate methods

@interface UITableViewController : UIViewController <UITableViewDelegate, UITableViewDataSource> {
	int _tableViewStyle;
	id _keyboardSupport;
}
@property(retain, nonatomic) UITableView* tableView;
// inherited: -(id)init;
-(id)initWithStyle:(int)style;
// inherited: -(void)dealloc;
-(id)existingTableView;
// declared property getter: -(id)tableView;
// declared property setter: -(void)setTableView:(id)view;
// inherited: -(void)loadView;
// inherited: -(void)viewWillAppear:(BOOL)view;
// inherited: -(void)viewWillDisappear:(BOOL)view;
// inherited: -(void)viewDidAppear:(BOOL)view;
-(void)setEditing:(BOOL)editing animated:(BOOL)animated;
-(void)_adjustTableForKeyboardInfo:(id)keyboardInfo;
// in a protocol: -(int)tableView:(id)view numberOfRowsInSection:(int)section;
// in a protocol: -(id)tableView:(id)view cellForRowAtIndexPath:(id)indexPath;
// in a protocol: -(void)tableView:(id)view willBeginEditingRowAtIndexPath:(id)indexPath;
// in a protocol: -(void)tableView:(id)view didEndEditingRowAtIndexPath:(id)indexPath;
@end

Method overloading in subclass is very common in OO design, but such information is useless when generating headers. Yet, by default a class dumper wouldn't know if an implementation is overloaded or a new method. If it's not useful, why not hide them? class-dump-z does that.

Another class of useless information are those being implemented to adopt a protocol. class-dump-z can also filter them out.

If you are running class-dump-z outside of the iPhoneOS, or you haven't installed the SDK, you have to tell class-dump-z where can the libraries be found by the -y switch. If you using using firmware 3.1, because all framework binaries are removed, hiding inherited methods from external frameworks won't work properly.

Readable argument names

• class-dump-? -C UIImageDeprecated UIKit

No more meaningless fpXX. class-dump-z will give a suitable name to each argument using Apple's coding style guide.

Correct header generation

The headers generated by -H are not immediately usable because the imports usually points to non-existing .h files. There is even a page dedicated to fixing this problem.

class-dump-z now will see which library the external class comes from, and tries to make up a better .h file location to import.

Even with this change, headers generated by class-dump-z is generally not immediately usable either. This is usually because of name clash with Foundation and CoreFoundation objects. Most of the cases supplying the -X NS,CF flag to filter them out is enough to fix it.

Miscellaneous features

• Class attributes, e.g. __attribute__((visibility("hidden"))).
• Supports obscure type encodings, e.g. the C99 _Complex types, Objective-C class ivars with ≥2 protocols, GC-invisible pointers, etc.
• Put that star on the left or right, I like int* x more, some people like int *x more. With the -R switch one can switch between the two styles easily.
• Put a space or not after the +/-. With the -b switch one can choose to use - (void)hello or -(void)hello.

What's missing

There are some features I don't find them immediately useful, so they are not supported yet.

Sort by inheritance (-I flag), Recursive dumping (-r)

These are not easy to implement and I find them not so useful so I left them out.