diff options
Diffstat (limited to 'gc/include/gc_cpp.h')
| -rw-r--r-- | gc/include/gc_cpp.h | 352 |
1 files changed, 0 insertions, 352 deletions
diff --git a/gc/include/gc_cpp.h b/gc/include/gc_cpp.h deleted file mode 100644 index 2b3a138..0000000 --- a/gc/include/gc_cpp.h +++ /dev/null @@ -1,352 +0,0 @@ -#ifndef GC_CPP_H -#define GC_CPP_H -/**************************************************************************** -Copyright (c) 1994 by Xerox Corporation. All rights reserved. - -THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED -OR IMPLIED. ANY USE IS AT YOUR OWN RISK. - -Permission is hereby granted to use or copy this program for any -purpose, provided the above notices are retained on all copies. -Permission to modify the code and to distribute modified code is -granted, provided the above notices are retained, and a notice that -the code was modified is included with the above copyright notice. -**************************************************************************** - -C++ Interface to the Boehm Collector - - John R. Ellis and Jesse Hull - -This interface provides access to the Boehm collector. It provides -basic facilities similar to those described in "Safe, Efficient -Garbage Collection for C++", by John R. Elis and David L. Detlefs -(ftp://ftp.parc.xerox.com/pub/ellis/gc). - -All heap-allocated objects are either "collectable" or -"uncollectable". Programs must explicitly delete uncollectable -objects, whereas the garbage collector will automatically delete -collectable objects when it discovers them to be inaccessible. -Collectable objects may freely point at uncollectable objects and vice -versa. - -Objects allocated with the built-in "::operator new" are uncollectable. - -Objects derived from class "gc" are collectable. For example: - - class A: public gc {...}; - A* a = new A; // a is collectable. - -Collectable instances of non-class types can be allocated using the GC -(or UseGC) placement: - - typedef int A[ 10 ]; - A* a = new (GC) A; - -Uncollectable instances of classes derived from "gc" can be allocated -using the NoGC placement: - - class A: public gc {...}; - A* a = new (NoGC) A; // a is uncollectable. - -Both uncollectable and collectable objects can be explicitly deleted -with "delete", which invokes an object's destructors and frees its -storage immediately. - -A collectable object may have a clean-up function, which will be -invoked when the collector discovers the object to be inaccessible. -An object derived from "gc_cleanup" or containing a member derived -from "gc_cleanup" has a default clean-up function that invokes the -object's destructors. Explicit clean-up functions may be specified as -an additional placement argument: - - A* a = ::new (GC, MyCleanup) A; - -An object is considered "accessible" by the collector if it can be -reached by a path of pointers from static variables, automatic -variables of active functions, or from some object with clean-up -enabled; pointers from an object to itself are ignored. - -Thus, if objects A and B both have clean-up functions, and A points at -B, B is considered accessible. After A's clean-up is invoked and its -storage released, B will then become inaccessible and will have its -clean-up invoked. If A points at B and B points to A, forming a -cycle, then that's considered a storage leak, and neither will be -collectable. See the interface gc.h for low-level facilities for -handling such cycles of objects with clean-up. - -The collector cannot guarrantee that it will find all inaccessible -objects. In practice, it finds almost all of them. - - -Cautions: - -1. Be sure the collector has been augmented with "make c++". - -2. If your compiler supports the new "operator new[]" syntax, then -add -DGC_OPERATOR_NEW_ARRAY to the Makefile. - -If your compiler doesn't support "operator new[]", beware that an -array of type T, where T is derived from "gc", may or may not be -allocated as a collectable object (it depends on the compiler). Use -the explicit GC placement to make the array collectable. For example: - - class A: public gc {...}; - A* a1 = new A[ 10 ]; // collectable or uncollectable? - A* a2 = new (GC) A[ 10 ]; // collectable - -3. The destructors of collectable arrays of objects derived from -"gc_cleanup" will not be invoked properly. For example: - - class A: public gc_cleanup {...}; - A* a = new (GC) A[ 10 ]; // destructors not invoked correctly - -Typically, only the destructor for the first element of the array will -be invoked when the array is garbage-collected. To get all the -destructors of any array executed, you must supply an explicit -clean-up function: - - A* a = new (GC, MyCleanUp) A[ 10 ]; - -(Implementing clean-up of arrays correctly, portably, and in a way -that preserves the correct exception semantics requires a language -extension, e.g. the "gc" keyword.) - -4. Compiler bugs: - -* Solaris 2's CC (SC3.0) doesn't implement t->~T() correctly, so the -destructors of classes derived from gc_cleanup won't be invoked. -You'll have to explicitly register a clean-up function with -new-placement syntax. - -* Evidently cfront 3.0 does not allow destructors to be explicitly -invoked using the ANSI-conforming syntax t->~T(). If you're using -cfront 3.0, you'll have to comment out the class gc_cleanup, which -uses explicit invocation. - -5. GC name conflicts: - -Many other systems seem to use the identifier "GC" as an abbreviation -for "Graphics Context". Since version 5.0, GC placement has been replaced -by UseGC. GC is an alias for UseGC, unless GC_NAME_CONFLICT is defined. - -****************************************************************************/ - -#include "gc.h" - -#ifndef THINK_CPLUS -#define _cdecl -#endif - -#if ! defined( GC_NO_OPERATOR_NEW_ARRAY ) \ - && !defined(_ENABLE_ARRAYNEW) /* Digimars */ \ - && (defined(__BORLANDC__) && (__BORLANDC__ < 0x450) \ - || (defined(__GNUC__) && \ - (__GNUC__ < 2 || __GNUC__ == 2 && __GNUC_MINOR__ < 6)) \ - || (defined(__WATCOMC__) && __WATCOMC__ < 1050)) -# define GC_NO_OPERATOR_NEW_ARRAY -#endif - -#if !defined(GC_NO_OPERATOR_NEW_ARRAY) && !defined(GC_OPERATOR_NEW_ARRAY) -# define GC_OPERATOR_NEW_ARRAY -#endif - -enum GCPlacement {UseGC, -#ifndef GC_NAME_CONFLICT - GC=UseGC, -#endif - NoGC, PointerFreeGC}; - -class gc {public: - inline void* operator new( size_t size ); - inline void* operator new( size_t size, GCPlacement gcp ); - inline void* operator new( size_t size, void *p ); - /* Must be redefined here, since the other overloadings */ - /* hide the global definition. */ - inline void operator delete( void* obj ); - inline void operator delete( void*, void* ); - -#ifdef GC_OPERATOR_NEW_ARRAY - inline void* operator new[]( size_t size ); - inline void* operator new[]( size_t size, GCPlacement gcp ); - inline void* operator new[]( size_t size, void *p ); - inline void operator delete[]( void* obj ); - inline void gc::operator delete[]( void*, void* ); -#endif /* GC_OPERATOR_NEW_ARRAY */ - }; - /* - Instances of classes derived from "gc" will be allocated in the - collected heap by default, unless an explicit NoGC placement is - specified. */ - -class gc_cleanup: virtual public gc {public: - inline gc_cleanup(); - inline virtual ~gc_cleanup(); -private: - inline static void _cdecl cleanup( void* obj, void* clientData );}; - /* - Instances of classes derived from "gc_cleanup" will be allocated - in the collected heap by default. When the collector discovers an - inaccessible object derived from "gc_cleanup" or containing a - member derived from "gc_cleanup", its destructors will be - invoked. */ - -extern "C" {typedef void (*GCCleanUpFunc)( void* obj, void* clientData );} - -#ifdef _MSC_VER - // Disable warning that "no matching operator delete found; memory will - // not be freed if initialization throws an exception" -# pragma warning(disable:4291) -#endif - -inline void* operator new( - size_t size, - GCPlacement gcp, - GCCleanUpFunc cleanup = 0, - void* clientData = 0 ); - /* - Allocates a collectable or uncollected object, according to the - value of "gcp". - - For collectable objects, if "cleanup" is non-null, then when the - allocated object "obj" becomes inaccessible, the collector will - invoke the function "cleanup( obj, clientData )" but will not - invoke the object's destructors. It is an error to explicitly - delete an object allocated with a non-null "cleanup". - - It is an error to specify a non-null "cleanup" with NoGC or for - classes derived from "gc_cleanup" or containing members derived - from "gc_cleanup". */ - - -#ifdef _MSC_VER - /** This ensures that the system default operator new[] doesn't get - * undefined, which is what seems to happen on VC++ 6 for some reason - * if we define a multi-argument operator new[]. - * There seems to be really redirect new in this environment without - * including this everywhere. - */ - void *operator new[]( size_t size ); - - void operator delete[](void* obj); - - void* operator new( size_t size); - - void operator delete(void* obj); - - // This new operator is used by VC++ in case of Debug builds ! - void* operator new( size_t size, - int ,//nBlockUse, - const char * szFileName, - int nLine ); -#endif /* _MSC_VER */ - - -#ifdef GC_OPERATOR_NEW_ARRAY - -inline void* operator new[]( - size_t size, - GCPlacement gcp, - GCCleanUpFunc cleanup = 0, - void* clientData = 0 ); - /* - The operator new for arrays, identical to the above. */ - -#endif /* GC_OPERATOR_NEW_ARRAY */ - -/**************************************************************************** - -Inline implementation - -****************************************************************************/ - -inline void* gc::operator new( size_t size ) { - return GC_MALLOC( size );} - -inline void* gc::operator new( size_t size, GCPlacement gcp ) { - if (gcp == UseGC) - return GC_MALLOC( size ); - else if (gcp == PointerFreeGC) - return GC_MALLOC_ATOMIC( size ); - else - return GC_MALLOC_UNCOLLECTABLE( size );} - -inline void* gc::operator new( size_t size, void *p ) { - return p;} - -inline void gc::operator delete( void* obj ) { - GC_FREE( obj );} - -inline void gc::operator delete( void*, void* ) {} - -#ifdef GC_OPERATOR_NEW_ARRAY - -inline void* gc::operator new[]( size_t size ) { - return gc::operator new( size );} - -inline void* gc::operator new[]( size_t size, GCPlacement gcp ) { - return gc::operator new( size, gcp );} - -inline void* gc::operator new[]( size_t size, void *p ) { - return p;} - -inline void gc::operator delete[]( void* obj ) { - gc::operator delete( obj );} - -inline void gc::operator delete[]( void*, void* ) {} - -#endif /* GC_OPERATOR_NEW_ARRAY */ - - -inline gc_cleanup::~gc_cleanup() { - GC_REGISTER_FINALIZER_IGNORE_SELF( GC_base(this), 0, 0, 0, 0 );} - -inline void gc_cleanup::cleanup( void* obj, void* displ ) { - ((gc_cleanup*) ((char*) obj + (ptrdiff_t) displ))->~gc_cleanup();} - -inline gc_cleanup::gc_cleanup() { - GC_finalization_proc oldProc; - void* oldData; - void* base = GC_base( (void *) this ); - if (0 != base) { - // Don't call the debug version, since this is a real base address. - GC_register_finalizer_ignore_self( - base, (GC_finalization_proc)cleanup, (void*) ((char*) this - (char*) base), - &oldProc, &oldData ); - if (0 != oldProc) { - GC_register_finalizer_ignore_self( base, oldProc, oldData, 0, 0 );}}} - -inline void* operator new( - size_t size, - GCPlacement gcp, - GCCleanUpFunc cleanup, - void* clientData ) -{ - void* obj; - - if (gcp == UseGC) { - obj = GC_MALLOC( size ); - if (cleanup != 0) - GC_REGISTER_FINALIZER_IGNORE_SELF( - obj, cleanup, clientData, 0, 0 );} - else if (gcp == PointerFreeGC) { - obj = GC_MALLOC_ATOMIC( size );} - else { - obj = GC_MALLOC_UNCOLLECTABLE( size );}; - return obj;} - - -#ifdef GC_OPERATOR_NEW_ARRAY - -inline void* operator new[]( - size_t size, - GCPlacement gcp, - GCCleanUpFunc cleanup, - void* clientData ) -{ - return ::operator new( size, gcp, cleanup, clientData );} - -#endif /* GC_OPERATOR_NEW_ARRAY */ - - -#endif /* GC_CPP_H */ - |