darling-corefoundation/NSInvocation.m

//
//  NSInvocation.m
//  CoreFoundation
//
//  Copyright (c) 2014 Apportable. All rights reserved.
//

#import <Foundation/NSArray.h>
#import <Foundation/NSData.h>
#import <Foundation/NSException.h>
#import <Foundation/NSInvocation.h>
#import <Foundation/NSMethodSignature.h>

#import "Block_private.h"
#import "NSInvocationInternal.h"
#import "NSObjCRuntimeInternal.h"

#import <objc/message.h>
#import <objc/runtime.h>
#import <dispatch/dispatch.h>


@implementation NSInvocation

+ (void)load
{
#if LEGACY_METHOD
    // signature should be @encode(long long) @encode(id) @encode(SEL) @encode(SEL) @encode(marg_list)
    class_addMethod([NSObject class], @selector(forward::), (IMP)&_CF_forwarding_prep_0, "q@::^v");
#else
    objc_setForwardHandler(&_CF_forwarding_prep_0, &_CF_forwarding_prep_1);
#endif
}

- (void **)_idxToArg:(NSUInteger)idx
{
    if (idx == 0)
    {
        return _retdata;
    }

    NSMethodType *argType = [_signature _argInfo:idx];
    return _frame + argType->offset;
}

// NSInvocation can retain its arguments, including copies of C
// strings which it places in an NSData. For such strings, this method
// therefore modifies the frame to use an internal pointer to the
// NSData rather than to the original string.
- (void)_retainArgument:(NSUInteger)idx
{
    NSMethodType *argInfo = [_signature _argInfo: idx];
    const char *type = stripQualifiersAndComments(argInfo->type);
    void **arg = [self _idxToArg: idx];

    if (type[0] == _C_ID)
    {
        id object = (id) *arg;
        if (object != nil)
        {
            [_container addObject: (id) *arg];
        }
    }
    else if (type[0] == _C_CHARPTR)
    {
        char *str = (char *) *arg;
        if (str != NULL)
        {
            NSUInteger length = strlen(str) + 1;
            NSData *data = [NSData dataWithBytes: str length: length];
            *arg = [data bytes];
            [_container addObject: data];
        }
    }
}

- (void) _addAttachedObject: (id) object
{
    if (_container == nil)
    {
        _container = [[NSMutableArray alloc] init];
    }
    [_container addObject: object];
}

- (instancetype)initWithMethodSignature:(NSMethodSignature *)sig
{
    if (sig == nil)
    {
        [self release];
        [NSException raise:NSInvalidArgumentException format:@"signature cannot be nil"];
        return nil;
    }

    self = [super init];

    if (self)
    {
        _signature = [sig retain];

        NSUInteger retSize = 0;
        NSGetSizeAndAlignment([_signature methodReturnType], &retSize, NULL);
        retSize = MAX(retSize, RET_SIZE_ARGS);
        _retdata = calloc(retSize + [_signature frameLength], 1);
        _frame = _retdata + retSize;

        if ([sig _stret])
        {
            // Set up the return value pointer for the objc_msgSend_stret call.
            void **ret = _frame;
            *ret = _retdata;
        }
    }

    return self;
}

- (instancetype)init
{
    [self release]; // init should not work on NSInvocation
    return nil;
}

- (void)dealloc
{
    [_container release];
    [_signature release];
    free(_retdata);
    [super dealloc];
}

+ (instancetype)invocationWithMethodSignature:(NSMethodSignature *)sig
{
    return [[[self alloc] initWithMethodSignature:sig] autorelease];
}

- (NSMethodSignature *)methodSignature
{
    return _signature;
}

- (void)retainArguments
{
    if (_retainedArgs)
    {
        return;
    }
    _retainedArgs = YES;

    NSUInteger capacity = [_signature numberOfArguments] + 1; // Add one for return value.
    if (_container == nil)
    {
        _container = [[NSMutableArray alloc] initWithCapacity: capacity];
    }

    for (NSUInteger idx = 0; idx < capacity; idx++)
    {
        [self _retainArgument:idx];
    }
}

- (BOOL)argumentsRetained
{
    return _retainedArgs;
}

- (id)target
{
    id t = nil;
    [self getArgument:&t atIndex:0];
    return t;
}

- (void)setTarget:(id)target
{
    [self setArgument:&target atIndex:0];
}

- (SEL)selector
{
    SEL sel;
    [self getArgument:&sel atIndex:1];
    return sel;
}

- (void)setSelector:(SEL)selector
{
    [self setArgument:&selector atIndex:1];
}

- (void)getReturnValue:(void *)retLoc
{
    [self getArgument:retLoc atIndex:-1];
}

- (void)setReturnValue:(void *)retLoc
{
    [self setArgument:retLoc atIndex:-1];
}

- (void)getArgument:(void *)argumentLocation atIndex:(NSInteger)idx
{
    // idx initially goes like this:
    // -1: return value
    // 0: self
    // 1: _cmd
    // 2+: arguments
    // Thus we add 1 to get an index into _frame.
    idx++;

    if (idx > [_signature numberOfArguments] || idx < 0)
    {
        @throw [NSException exceptionWithName:NSInvalidArgumentException reason:nil userInfo:nil];
    }

    NSMethodType *argInfo = [_signature _argInfo:idx];
    void **arg = [self _idxToArg:idx];

    memcpy(argumentLocation, arg, argInfo->size);
}

- (void)setArgument:(void *)argumentLocation atIndex:(NSInteger)idx
{
    // idx initially goes like this:
    // -1: return value
    // 0: self
    // 1: _cmd
    // 2+: arguments
    // Thus we add 1 to get an index into _frame.
    idx++;

    if (idx > [_signature numberOfArguments] || idx < 0)
    {
        @throw [NSException exceptionWithName:NSInvalidArgumentException reason:nil userInfo:nil];
    }

    NSMethodType *argInfo = [_signature _argInfo:idx];
    void **arg = [self _idxToArg:idx];

    memcpy(arg, argumentLocation, argInfo->size);

    if (_retainedArgs)
    {
        [self _retainArgument:idx];
    }
}

- (void)invoke
{
    id target = nil;
    [self getArgument:&target atIndex:0];

    if (target == nil)
    {
        return;
    }

    static Class NSBlockClass = Nil;
    static dispatch_once_t once = 0L;
    dispatch_once(&once, ^{
        // __NSGlobalBlock -> NSBlock
        NSBlockClass = class_getSuperclass(class_getSuperclass(object_getClass(^{})));
    });

    BOOL blockClass = NO;
    Class cls = object_getClass(target);

    while (cls != Nil)
    {
        if (cls == NSBlockClass)
        {
            blockClass = YES;
        }
        cls = class_getSuperclass(cls);
    }

    char rettype = [_signature methodReturnType][0];

    if (blockClass)
    {
        struct Block_layout *block_layout = (struct Block_layout *)target;
        __invoke__(block_layout->invoke, _retdata, _frame, [_signature frameLength], rettype);
    }
    else if ([_signature _stret])
    {
        char dummy[RET_SIZE_ARGS];
        __invoke__(&objc_msgSend_stret, &dummy, _frame, [_signature frameLength], rettype);
    }
    else
    {
        __invoke__(&objc_msgSend, _retdata, _frame, [_signature frameLength], rettype);
    }

    if (_retainedArgs)
    {
        // Retain the return value.
        [self _retainArgument:0];
    }
}

- (void)invokeWithTarget:(id)target
{
    [self setTarget:target];
    [self invoke];
}

- (NSString *) debugDescription
{
    CFMutableStringRef description = CFStringCreateMutable(NULL, 0);
    CFStringAppend(description, (CFStringRef) [self description]);

    for (NSInteger index = -1; index < (NSInteger) [_signature numberOfArguments]; index++)
    {
        CFStringAppend(description, @"\n");

        switch (index)
        {
        case -1:
            CFStringAppend(description, @"return value");
            break;
        case 0:
            CFStringAppend(description, @"target");
            break;
        case 1:
            CFStringAppend(description, @"selector");
            break;
        default:
            CFStringAppendFormat(description, NULL, @"argument %ld", (long) index);
            break;
        }
        CFStringAppend(description, @": ");

        NSMethodType *argInfo = [_signature _argInfo: index + 1];
        CFStringAppendFormat(description, NULL, @"{%s} ", argInfo->type);

        char type = stripQualifiersAndComments(argInfo->type)[0];
        switch (type)
        {
        case _C_VOID:
            CFStringAppend(description, @"void");
            break;
        case _C_CLASS:
            {
                Class class;
                [self getArgument: &class atIndex: index];
                if (class == Nil)
                {
                    CFStringAppend(description, @"Nil");
                }
                else
                {
                    CFStringAppendFormat(description, NULL, @"%s", class_getName(class));
                }
                break;
            }
        case _C_SEL:
            {
                SEL selector;
                [self getArgument: &selector atIndex: index];
                if (!selector)
                {
                    CFStringAppend(description, @"null");
                }
                else
                {
                    CFStringAppendFormat(description, NULL, @"%s", sel_getName(selector));
                }
                break;
            }

#define HANDLE(_c_type, type, format) \
        case _c_type: \
            { \
                type value; \
                [self getArgument: &value atIndex: index]; \
                CFStringAppendFormat(description, NULL, format, value); \
                break; \
            }

        HANDLE(_C_CHR, char, @"%c");
        HANDLE(_C_UCHR, unsigned char, @"%u");
        HANDLE(_C_BOOL, _Bool, @"%d");
        HANDLE(_C_SHT, short, @"%d");
        HANDLE(_C_USHT, unsigned short, @"%u");
        HANDLE(_C_INT, int, @"%d");
        HANDLE(_C_UINT, unsigned int, @"%u");
        HANDLE(_C_LNG, long, @"%ld");
        HANDLE(_C_ULNG, unsigned long, @"%lu");
        HANDLE(_C_LNG_LNG, long long, @"%lld");
        HANDLE(_C_ULNG_LNG, unsigned long long, @"%llu");
        HANDLE(_C_FLT, float, @"%f");
        HANDLE(_C_DBL, double, @"%f");
        HANDLE(_C_CHARPTR, const char *, @"%s");
        HANDLE(_C_ID, id, @"%p");
        HANDLE(_C_PTR, void *, @"%p");

#undef HANDLE

        default:
            {
                const void *ptr = [self _idxToArg: index + 1];
                CFDataRef data = CFDataCreateWithBytesNoCopy(NULL, ptr, argInfo->size, kCFAllocatorNull);
                CFStringAppend(description, (CFStringRef) [data description]);
                CFRelease(data);
                break;
            }
        }
    }

    CFAutorelease(description);
    return description;
}

@end