292 lines
13 KiB
C
292 lines
13 KiB
C
|
/////////////////////////////////////////////////////////////////////////////
|
||
|
// Name: wx/cocoa/objc/objc_uniquifying.h
|
||
|
// Purpose: Allows wxWidgets code to get a direct pointer to a compiled
|
||
|
// Objective-C class and provides a method to fix up the
|
||
|
// name to include a unique identifier (currently the address
|
||
|
// of the objc_class structure).
|
||
|
// Author: David Elliott <dfe@cox.net>
|
||
|
// Modified by:
|
||
|
// Created: 2007/05/15
|
||
|
// RCS-ID: $Id$
|
||
|
// Copyright: (c) 2007 Software 2000 Ltd.
|
||
|
// Licence: wxWindows licence
|
||
|
/////////////////////////////////////////////////////////////////////////////
|
||
|
|
||
|
#ifndef __WX_COCOA_OBJC_CLASS_H__
|
||
|
#define __WX_COCOA_OBJC_CLASS_H__
|
||
|
|
||
|
#if wxUSE_OBJC_UNIQUIFYING
|
||
|
|
||
|
// objc_getClass and stuff
|
||
|
#include <objc/objc-runtime.h>
|
||
|
|
||
|
////////////// Objective-C uniquifying implementation //////////////
|
||
|
|
||
|
template <typename ObjcType>
|
||
|
class wxObjcClassInitializer;
|
||
|
|
||
|
template <typename ObjcType>
|
||
|
class UniquifiedName;
|
||
|
|
||
|
template <typename ObjcType>
|
||
|
class wxObjcCompilerInformation
|
||
|
{
|
||
|
friend class wxObjcClassInitializer<ObjcType>;
|
||
|
friend class UniquifiedName<ObjcType>;
|
||
|
private:
|
||
|
// GetCompiledClass must be partially specialized for an ObjcType
|
||
|
// If you're not using it, implement an inline returning NULL
|
||
|
inline static struct objc_class * GetCompiledClass();
|
||
|
|
||
|
// sm_theClassName must be partially specialized for each type
|
||
|
static const char sm_theClassName[];
|
||
|
|
||
|
// GetSuperclass must be specialized. Typically one of two ways:
|
||
|
// 1. objc_getClass("SomeRealClassName")
|
||
|
// 2. wxGetObjcClass_SomeWxClassName();
|
||
|
inline static struct objc_class *GetSuperclass();
|
||
|
};
|
||
|
|
||
|
|
||
|
template <typename ObjcType>
|
||
|
struct UniquifiedName
|
||
|
{
|
||
|
// We're going for OriginalClassName@ClassStructureAddress
|
||
|
// Therefore our size is the sizeof the original class name constant string (which includes the terminating NULL)
|
||
|
// plus the sizeof a pointer to struct objc_class times two (two hex digits for each byte) plus 3 for "@0x"
|
||
|
typedef char Type[sizeof(wxObjcCompilerInformation<ObjcType>::sm_theClassName) + (sizeof(struct objc_class*)<<1) + 3];
|
||
|
static void Init(Type m_theString, const objc_class *aClass)
|
||
|
{
|
||
|
snprintf(const_cast<char*>(m_theString), sizeof(Type), "%s@%p", wxObjcCompilerInformation<ObjcType>::sm_theClassName, aClass);
|
||
|
}
|
||
|
};
|
||
|
|
||
|
template <typename ObjcType>
|
||
|
class wxObjcClassInitializer
|
||
|
{
|
||
|
public:
|
||
|
static struct objc_class* Get()
|
||
|
{
|
||
|
static wxObjcClassInitializer<ObjcType> s_theInstance;
|
||
|
s_theInstance.noop(); // Make the compiler think we need this instance
|
||
|
return wxObjcCompilerInformation<ObjcType>::GetCompiledClass();
|
||
|
}
|
||
|
private:
|
||
|
void noop()
|
||
|
{}
|
||
|
// This "constructor" operates solely on static data
|
||
|
// It exists so that we can take advantage of a function-static
|
||
|
// "instance" of this class to do the static data initialization.
|
||
|
wxObjcClassInitializer()
|
||
|
{
|
||
|
// Objective-C class initialization occurs before C++ static initialization because the
|
||
|
// libobjc.dylib gets notified directly by dyld on Tiger.
|
||
|
// Therefore, even though we change the name, the class is still registered with the
|
||
|
// original name. We unfortunately can't change that.
|
||
|
|
||
|
// The first time the class is loaded, Objective-C will already have fixed up the super_class
|
||
|
// and isa->isa and isa->super_class variables so much of this won't do anything. But
|
||
|
// the next time the class is loaded, Objective-C will ignore it and thus we need to
|
||
|
// initialize the data structures appropriately.
|
||
|
|
||
|
// Ideally we'd have some sort of lock here, but we depend on the fact that we get called
|
||
|
// just before the first time someone wants to send a class message so it should be
|
||
|
// reasonably safe to do this without any locks.
|
||
|
|
||
|
struct objc_class &theClassData = *wxObjcCompilerInformation<ObjcType>::GetCompiledClass();
|
||
|
// Initialize the uniquified class name
|
||
|
UniquifiedName<ObjcType>::Init(sm_theUniquifiedClassName, &theClassData);
|
||
|
|
||
|
//////// Class Initialization ////////
|
||
|
// Use objc_getClass to fix up the superclass pointer
|
||
|
theClassData.super_class = wxObjcCompilerInformation<ObjcType>::GetSuperclass();
|
||
|
// Fix up the compiler generated class struct to use the new name
|
||
|
theClassData.name = sm_theUniquifiedClassName;
|
||
|
|
||
|
//////// Meta-Class Initialization ////////
|
||
|
// theClassData.isa is the metaclass pointer
|
||
|
// Globals on Darwin use PC-relative access (slow) so it's quicker to use theClassData.isa
|
||
|
|
||
|
// In any object hierarchy a metaclass's metaclass is always the root class's metaclass
|
||
|
// Therefore, our superclass's metaclass's metaclass should already be the root class's metaclass
|
||
|
theClassData.isa->isa = theClassData.super_class->isa->isa;
|
||
|
// A metaclass's superclass is always the superclass's metaclass.
|
||
|
theClassData.isa->super_class = theClassData.super_class->isa;
|
||
|
// Fix up the compiler generated metaclass struct to use the new name
|
||
|
theClassData.isa->name = sm_theUniquifiedClassName;
|
||
|
|
||
|
// We need to set the initialized flag because after we change the name, Objective-C can't
|
||
|
// look us up by name because we're only registered with the original name.
|
||
|
theClassData.isa->info |= CLS_INITIALIZED;
|
||
|
}
|
||
|
wxObjcClassInitializer(const wxObjcClassInitializer&); // NO COPY
|
||
|
wxObjcClassInitializer& operator =(const wxObjcClassInitializer&); // NO ASSIGN
|
||
|
static typename UniquifiedName<ObjcType>::Type sm_theUniquifiedClassName;
|
||
|
};
|
||
|
|
||
|
template<typename ObjcType>
|
||
|
typename UniquifiedName<ObjcType>::Type wxObjcClassInitializer<ObjcType>::sm_theUniquifiedClassName;
|
||
|
|
||
|
// WX_DECLARE_GET_OBJC_CLASS
|
||
|
// Declares a function to get a direct pointer to an objective-C class.
|
||
|
// The class is guaranteed to be usable.
|
||
|
// When wxCocoa is built into a Mach-O bundle this function allows the wxCocoa
|
||
|
// code to get a reference to the Objective-C class structure located in the
|
||
|
// same bundle. This allows a static wxCocoa library to be built into
|
||
|
// two different Mach-O bundles without having one bundle's Objective-C
|
||
|
// classes trample on the other's.
|
||
|
// Right now we toss the ObjcSuperClass parameter, but we might use it later.
|
||
|
#define WX_DECLARE_GET_OBJC_CLASS(ObjcClass,ObjcSuperClass) \
|
||
|
struct objc_class* wx_GetObjcClass_ ## ObjcClass();
|
||
|
|
||
|
// WX_IMPLEMENT_OBJC_GET_COMPILED_CLASS(ObjcClass)
|
||
|
// Provides an architecture-dependent way to get the direct pointer to the
|
||
|
// objc_class structure in the __OBJC segment.
|
||
|
// This takes advantage of the fact that the Objective-C compiler uses guessable
|
||
|
// local assembler labels for the class structures.
|
||
|
// Those class structures are only available on the Objective-C file containing the
|
||
|
// @implementation block.
|
||
|
|
||
|
#if 1
|
||
|
// Generic implementation - Tested on i386 and PPC. Should work in all cases.
|
||
|
// This is a hack that depends on GCC asm symbol names.
|
||
|
// The static variable winds up being initialized with a direct reference to the appropriate
|
||
|
// L_OBJC_CLASS and no global symbol reference is generated because nothing uses the global symbol
|
||
|
// except for the static initializer which does it directly.
|
||
|
// The generated assembler for s_objc_class_ptr is basically like this:
|
||
|
// _s_objc_class_ptr_ObjcClass:
|
||
|
// .long L_OBJC_CLASS_ObjcClass
|
||
|
// Once that static symbol is defined, the function implementation is easy for GCC to generate.
|
||
|
// Do note that return &s_objc_class_data_ObjcClass won't work. The code is wrong in the case.
|
||
|
#define WX_IMPLEMENT_OBJC_GET_COMPILED_CLASS(ObjcClass) \
|
||
|
extern "C" objc_class s_objc_class_data_ ## ObjcClass asm("L_OBJC_CLASS_" #ObjcClass); \
|
||
|
static objc_class * s_objc_class_ptr_ ## ObjcClass = &s_objc_class_data_ ## ObjcClass; \
|
||
|
template<> \
|
||
|
inline objc_class * wxObjcCompilerInformation<ObjcClass>::GetCompiledClass() \
|
||
|
{ \
|
||
|
return s_objc_class_ptr_## ObjcClass; \
|
||
|
}
|
||
|
|
||
|
#elif defined(__i386__)
|
||
|
// Not used because the generic implementation seems to work fine.
|
||
|
// But this is here since it was written beforehand and it also works.
|
||
|
|
||
|
// This is based on the code GCC generates for accessing file-static data on i386.
|
||
|
// The i386 PC-relative addressing happens in this manner
|
||
|
// 1. The program counter is placed into ecx using the code that GCC should have
|
||
|
// already generated.
|
||
|
// 2. A label is placed directly after the call to get the program counter.
|
||
|
// 3. The Load Effective Address instruction is used to add the offset of the
|
||
|
// local assembler label we're interested in minus the local assembler label
|
||
|
// from step 2 to the program counter register in ecx and place the result
|
||
|
// into the result register (typically eax if not inlined).
|
||
|
#define WX_IMPLEMENT_OBJC_GET_COMPILED_CLASS(ObjcClass) \
|
||
|
template<> \
|
||
|
inline objc_class * wxObjcCompilerInformation<ObjcClass>::GetCompiledClass() \
|
||
|
{ \
|
||
|
register struct objc_class *retval; \
|
||
|
asm \
|
||
|
( "call ___i686.get_pc_thunk.cx\n" \
|
||
|
"\"LPC_FOR_GET_CLASS_" #ObjcClass "\":\n\t" \
|
||
|
"leal L_OBJC_CLASS_" #ObjcClass "-\"LPC_FOR_GET_CLASS_" #ObjcClass "\"(%%ecx), %0" \
|
||
|
: "=r"(retval) \
|
||
|
: \
|
||
|
: "ecx" \
|
||
|
); \
|
||
|
return retval; \
|
||
|
}
|
||
|
|
||
|
#elif defined(__ppc__)
|
||
|
// Not used because the generic implementation seems to work fine.
|
||
|
// But this is here since it was written beforehand and it also works.
|
||
|
|
||
|
// This is based on the code GCC generates for accessing file-static data on PPC.
|
||
|
// The PowerPC PC-relative addressing happens in this manner
|
||
|
// 1. The link register is saved (mflr) to a temporary (we re-use the output register for this)
|
||
|
// 2. An unconditional branch instruction (bcl) "branches" to the following address (labeled)
|
||
|
// 3. The link register (filled in by bcl) is saved to r10 (a temporary)
|
||
|
// 4. The previous link register is restored (mtlr) (from the output register we were using as a temporary)
|
||
|
// 5. The address of the LPC label as executed is added to the high 16 bits of the offset between that label and the static data we want
|
||
|
// and stored in a temporary register (r2)
|
||
|
// 6. That temporary register plus the low 16 bits of the offset are stored into the result register.
|
||
|
#define WX_IMPLEMENT_OBJC_GET_COMPILED_CLASS(ObjcClass) \
|
||
|
template<> \
|
||
|
inline objc_class * wxObjcCompilerInformation<ObjcClass>::GetCompiledClass() \
|
||
|
{ \
|
||
|
register struct objc_class *retval; \
|
||
|
asm \
|
||
|
( "mflr %0" \
|
||
|
"\n\tbcl 20, 31, \"LPC_FOR_GET_CLASS_" #ObjcClass "\"" \
|
||
|
"\n\"LPC_FOR_GET_CLASS_" #ObjcClass "\":" \
|
||
|
"\n\tmflr r10" \
|
||
|
"\n\tmtlr %0" \
|
||
|
"\n\taddis r2,r10,ha16(L_OBJC_CLASS_" #ObjcClass "-\"LPC_FOR_GET_CLASS_" #ObjcClass "\")" \
|
||
|
"\n\tla %0,lo16(L_OBJC_CLASS_" #ObjcClass "-\"LPC_FOR_GET_CLASS_" #ObjcClass "\")(r2)" \
|
||
|
: "=r" (retval) \
|
||
|
: \
|
||
|
: "r10","r2" \
|
||
|
); \
|
||
|
return retval; \
|
||
|
}
|
||
|
|
||
|
// TODO: __x86_64__, __ppc64__
|
||
|
#else // Can't wrie inline asm to bust into __OBJC segment
|
||
|
// This won't be used since the generic implementation takes precedence.
|
||
|
|
||
|
#warning "Don't know how to implement wxObjcCompilerInformation<ObjcClass>::GetCompiledClass on this platform"
|
||
|
|
||
|
#endif // platforms
|
||
|
|
||
|
// The WX_IMPLEMENT_OBJC_GET_SUPERCLASS macro implements the template specialization
|
||
|
// to get the superclass. This only works if it's a real superclass. If you are
|
||
|
// deriving from a class that's already being uniquified then you'd need to
|
||
|
// implement the specialization to call the appropriate get method instead.
|
||
|
#define WX_IMPLEMENT_OBJC_GET_SUPERCLASS(ObjcClass,ObjcSuperClass) \
|
||
|
template <> \
|
||
|
inline objc_class* wxObjcCompilerInformation<ObjcClass>::GetSuperclass() \
|
||
|
{ \
|
||
|
return objc_getClass(#ObjcSuperClass); \
|
||
|
}
|
||
|
|
||
|
// The WX_IMPLEMENT_OBJC_CLASS_NAME macro implements the template specialization
|
||
|
// of the sm_theClassName constant. As soon as this specialization is in place
|
||
|
// sizeof(sm_theClassName) will return the number of bytes at compile time.
|
||
|
#define WX_IMPLEMENT_OBJC_CLASS_NAME(ObjcClass) \
|
||
|
template <> \
|
||
|
const char wxObjcCompilerInformation<ObjcClass>::sm_theClassName[] = #ObjcClass;
|
||
|
|
||
|
// The WX_IMPLEMENT_GET_OBJC_CLASS macro combines all of these together and adds
|
||
|
// a global wx_GetObjcClass_ObjcClass() function.
|
||
|
#define WX_IMPLEMENT_GET_OBJC_CLASS(ObjcClass,ObjcSuperClass) \
|
||
|
WX_IMPLEMENT_OBJC_GET_COMPILED_CLASS(ObjcClass) \
|
||
|
WX_IMPLEMENT_OBJC_GET_SUPERCLASS(ObjcClass,ObjcSuperClass) \
|
||
|
WX_IMPLEMENT_OBJC_CLASS_NAME(ObjcClass) \
|
||
|
objc_class* wx_GetObjcClass_ ## ObjcClass() \
|
||
|
{ \
|
||
|
return wxObjcClassInitializer<ObjcClass>::Get(); \
|
||
|
}
|
||
|
|
||
|
// The WX_GET_OBJC_CLASS macro is intended to wrap the class name when the class
|
||
|
// is used as a message receiver (e.g. for calling class methods). When
|
||
|
// class name uniquifying is used, this calls the global function implemented
|
||
|
// in the Objective-C file containing the class @implementation.
|
||
|
#define WX_GET_OBJC_CLASS(ObjcClass) wx_GetObjcClass_ ## ObjcClass()
|
||
|
|
||
|
#else // wxUSE_OBJC_UNIQUIFYING
|
||
|
|
||
|
// Define WX_DECLARE_GET_OBJC_CLASS as nothing
|
||
|
#define WX_DECLARE_GET_OBJC_CLASS(ObjcClass,ObjcSuperClass)
|
||
|
// Define WX_IMPLEMENT_GET_OBJC_CLASS as nothing
|
||
|
#define WX_IMPLEMENT_GET_OBJC_CLASS(ObjcClass,ObjcSuperClass)
|
||
|
|
||
|
// Define WX_GET_OBJC_CLASS macro to output the class name and let the compiler do the normal thing
|
||
|
// The WX_GET_OBJC_CLASS macro is intended to wrap the class name when the class
|
||
|
// is used as a message receiver (e.g. for calling class methods). When
|
||
|
// class name uniquifying is not used, this is simply defined to be the class
|
||
|
// name which will allow the compiler to do the normal thing.
|
||
|
#define WX_GET_OBJC_CLASS(ObjcClass) ObjcClass
|
||
|
|
||
|
#endif // wxUSE_OBJC_UNIQUIFYING
|
||
|
|
||
|
#endif //ndef __WX_COCOA_OBJC_CLASS_H__
|