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//
// JSCocoaFFIClosure.m
// JSCocoa
//
// Created by Patrick Geiller on 29/07/08.
// Copyright 2008 __MyCompanyName__. All rights reserved.
//
#import "JSCocoaFFIClosure.h"
#import "JSCocoaController.h"
#include <sys/mman.h> // for mmap()
@implementation JSCocoaFFIClosure
//
// Common closure function, calling back closure object
//
void closure_function(ffi_cif* cif, void* resp, void** args, void* userdata)
{
[(id)userdata calledByClosureWithArgs:args returnValue:resp];
}
- (id)init
{
self = [super init];
argTypes = NULL;
encodings = NULL;
jsFunction = NULL;
return self;
}
//
// Cleanup : called by dealloc and finalize
//
- (void)cleanUp
{
if (encodings) [encodings release];
if (argTypes) free(argTypes);
if (jsFunction)
{
JSValueUnprotect(ctx, jsFunction);
[JSCocoaController downJSValueProtectCount];
}
//
// A strange crash reporting ??? as the source address is a deleted closure being called (happens with the bindings mechanism)
//
#if !TARGET_OS_IPHONE
if (munmap(closure, sizeof(closure)) == -1) NSLog(@"ffi closure munmap failed");
#endif
}
- (void)dealloc
{
// NSLog(@"deallocing closure %x IMP=%x", self, closure);
[self cleanUp];
[super dealloc];
}
- (void)finalize
{
[self cleanUp];
[super finalize];
}
- (void*)functionPointer
{
#if !TARGET_OS_IPHONE
return closure;
#else
return NULL;
#endif
}
//
// Bind a js function to closure. We'll jsValueProtect that function from GC.
//
- (IMP)setJSFunction:(JSValueRef)fn inContext:(JSContextRef)context argumentEncodings:(NSMutableArray*)argumentEncodings objC:(BOOL)objC
{
#if !TARGET_OS_IPHONE
if ([argumentEncodings count] == 0) return NULL;
encodings = argumentEncodings;
[encodings retain];
isObjC = objC;
unsigned int i, argumentCount = (unsigned int)([argumentEncodings count]-1);
argTypes = malloc(sizeof(ffi_type*)*argumentCount);
for (i=0; i<argumentCount; i++)
{
JSCocoaFFIArgument* arg = [argumentEncodings objectAtIndex:i+1];
argTypes[i] = [arg ffi_type];
}
if ((closure = mmap(NULL, sizeof(ffi_closure), PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0)) == (void*)-1)
{
NSLog(@"ffi closure mmap failed");
return NULL;
}
id returnValue = [argumentEncodings objectAtIndex:0];
ffi_status prep_status = ffi_prep_cif(&cif, FFI_DEFAULT_ABI, argumentCount, [returnValue ffi_type], argTypes);
if (prep_status != FFI_OK)
{
NSLog(@"ffi_prep_cif failed");
return NULL;
}
if (ffi_prep_closure(closure, &cif, closure_function, (void *)self) != FFI_OK)
{
NSLog(@"ffi_prep_closure failed");
return NULL;
}
if (mprotect(closure, sizeof(closure), PROT_READ | PROT_EXEC) == -1)
{
NSLog(@"ffi closure mprotect failed");
return NULL;
}
jsFunction = fn;
ctx = context;
// Protect function from GC
JSValueProtect(ctx, jsFunction);
[JSCocoaController upJSValueProtectCount];
return (IMP)closure;
#else
return NULL;
#endif
}
//
// Called by ffi
//
- (void)calledByClosureWithArgs:(void**)closureArgs returnValue:(void*)returnValue
{
JSObjectRef jsFunctionObject = JSValueToObject(ctx, jsFunction, NULL);
JSValueRef exception = NULL;
// ## Only objC for now. Need to test C function pointers.
// Argument count is encodings count minus return value
NSUInteger i, idx = 0, effectiveArgumentCount = [encodings count]-1;
// Skip self and selector
if (isObjC)
{
effectiveArgumentCount -= 2;
idx = 2;
}
// Convert arguments
JSValueRef* args = NULL;
if (effectiveArgumentCount)
{
args = malloc(effectiveArgumentCount*sizeof(JSValueRef));
for (i=0; i<effectiveArgumentCount; i++, idx++)
{
// +1 to skip return value
id encodingObject = [encodings objectAtIndex:idx+1];
id arg = [[JSCocoaFFIArgument alloc] init];
char encoding = [encodingObject typeEncoding];
if (encoding == '{') [arg setStructureTypeEncoding:[encodingObject structureTypeEncoding] withCustomStorage:*(void**)&closureArgs[idx]];
else [arg setTypeEncoding:[encodingObject typeEncoding] withCustomStorage:closureArgs[idx]];
args[i] = NULL;
[arg toJSValueRef:&args[i] inContext:ctx];
[arg release];
}
}
JSObjectRef jsThis = NULL;
// Create 'this'
if (isObjC)
jsThis = [JSCocoaController boxedJSObject:*(void**)closureArgs[0] inContext:ctx];
// Call !
JSValueRef jsReturnValue = JSObjectCallAsFunction(ctx, jsFunctionObject, jsThis, effectiveArgumentCount, args, &exception);
// Convert return value if it's not void
char encoding = [[encodings objectAtIndex:0] typeEncoding];
if (jsReturnValue && encoding != 'v')
{
[JSCocoaFFIArgument fromJSValueRef:jsReturnValue inContext:ctx typeEncoding:encoding fullTypeEncoding:[[encodings objectAtIndex:0] structureTypeEncoding] fromStorage:returnValue];
#ifdef __BIG_ENDIAN__
// As ffi always uses a sizeof(long) return value (even for chars and shorts), do some shifting
int size = [JSCocoaFFIArgument sizeOfTypeEncoding:encoding];
int paddedSize = sizeof(long);
long v;
if (size > 0 && size < paddedSize && paddedSize == 4)
{
v = *(long*)returnValue;
v = CFSwapInt32(v);
*(long*)returnValue = v;
}
#endif
}
if (effectiveArgumentCount) free(args);
// if (exception) NSLog(@"%@", [[JSCocoaController controllerFromContext:ctx] formatJSException:exception]);
if (exception)
{
@throw [NSException exceptionWithName:@"JSCocoa exception"
reason:[[JSCocoaController controllerFromContext:ctx] formatJSException:exception]
userInfo:nil];
}
}
@end
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