iOS block 源码详解2

/* * Block_private.h * * Copyright 2008-2010 Apple, Inc. Permission is hereby granted, free of charge, * to any person obtaining a copy of this software and associated documentation * files (the "Software"), to deal in the Software without restriction, * including without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to permit * persons to whom the Software is furnished to do so, subject to the following * conditions: *  * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. *  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. * */#ifndef _BLOCK_PRIVATE_H_#define _BLOCK_PRIVATE_H_#if !defined(BLOCK_EXPORT)#   if defined(__cplusplus)#       define BLOCK_EXPORT extern "C" #   else#       define BLOCK_EXPORT extern#   endif#endif#ifndef _MSC_VER#include <stdbool.h>#else/* MSVC doesn't have <stdbool.h>. Compensate. */typedef char bool;#define true (bool)1#define false (bool)0#endif#if defined(__cplusplus)extern "C" {#endifenum {    BLOCK_REFCOUNT_MASK =     (0xffff),    BLOCK_NEEDS_FREE =        (1 << 24),    BLOCK_HAS_COPY_DISPOSE =  (1 << 25),    BLOCK_HAS_CTOR =          (1 << 26), /* Helpers have C++ code. */    BLOCK_IS_GC =             (1 << 27),    BLOCK_IS_GLOBAL =         (1 << 28),    BLOCK_HAS_DESCRIPTOR =    (1 << 29)};/* Revised new layout. */struct Block_descriptor {    unsigned long int reserved;    unsigned long int size;    void (*copy)(void *dst, void *src);    void (*dispose)(void *);};struct Block_layout {    void *isa;    int flags;    int reserved;     void (*invoke)(void *, ...);    struct Block_descriptor *descriptor;    /* Imported variables. */};struct Block_byref {    void *isa;    struct Block_byref *forwarding;    int flags; /* refcount; */    int size;    void (*byref_keep)(struct Block_byref *dst, struct Block_byref *src);    void (*byref_destroy)(struct Block_byref *);    /* long shared[0]; */};struct Block_byref_header {    void *isa;    struct Block_byref *forwarding;    int flags;    int size;};/* Runtime support functions used by compiler when generating copy/dispose helpers. */enum {    /* See function implementation for a more complete description of these fields and combinations */    BLOCK_FIELD_IS_OBJECT   =  3,  /* id, NSObject, __attribute__((NSObject)), block, ... */    BLOCK_FIELD_IS_BLOCK    =  7,  /* a block variable */    BLOCK_FIELD_IS_BYREF    =  8,  /* the on stack structure holding the __block variable */    BLOCK_FIELD_IS_WEAK     = 16,  /* declared __weak, only used in byref copy helpers */    BLOCK_BYREF_CALLER      = 128  /* called from __block (byref) copy/dispose support routines. */};/* Runtime entry point called by compiler when assigning objects inside copy helper routines */BLOCK_EXPORT void _Block_object_assign(void *destAddr, const void *object, const int flags);    /* BLOCK_FIELD_IS_BYREF is only used from within block copy helpers *//* runtime entry point called by the compiler when disposing of objects inside dispose helper routine */BLOCK_EXPORT void _Block_object_dispose(const void *object, const int flags);/* Other support functions *//* Runtime entry to get total size of a closure */BLOCK_EXPORT unsigned long int Block_size(void *block_basic);/* the raw data space for runtime classes for blocks *//* class+meta used for stack, malloc, and collectable based blocks */BLOCK_EXPORT void * _NSConcreteStackBlock[32];BLOCK_EXPORT void * _NSConcreteMallocBlock[32];BLOCK_EXPORT void * _NSConcreteAutoBlock[32];BLOCK_EXPORT void * _NSConcreteFinalizingBlock[32];BLOCK_EXPORT void * _NSConcreteGlobalBlock[32];BLOCK_EXPORT void * _NSConcreteWeakBlockVariable[32];/* the intercept routines that must be used under GC */BLOCK_EXPORT void _Block_use_GC( void *(*alloc)(const unsigned long, const bool isOne, const bool isObject),                                  void (*setHasRefcount)(const void *, const bool),                                  void (*gc_assign_strong)(void *, void **),                                  void (*gc_assign_weak)(const void *, void *),                                  void (*gc_memmove)(void *, void *, unsigned long));/* earlier version, now simply transitional */BLOCK_EXPORT void _Block_use_GC5( void *(*alloc)(const unsigned long, const bool isOne, const bool isObject),                                  void (*setHasRefcount)(const void *, const bool),                                  void (*gc_assign_strong)(void *, void **),                                  void (*gc_assign_weak)(const void *, void *));BLOCK_EXPORT void _Block_use_RR( void (*retain)(const void *),                                 void (*release)(const void *));/* make a collectable GC heap based Block.  Not useful under non-GC. */BLOCK_EXPORT void *_Block_copy_collectable(const void *aBlock);/* thread-unsafe diagnostic */BLOCK_EXPORT const char *_Block_dump(const void *block);/* Obsolete *//* first layout */struct Block_basic {    void *isa;    int Block_flags;  /* int32_t */    int Block_size;  /* XXX should be packed into Block_flags */    void (*Block_invoke)(void *);    void (*Block_copy)(void *dst, void *src);  /* iff BLOCK_HAS_COPY_DISPOSE */    void (*Block_dispose)(void *);             /* iff BLOCK_HAS_COPY_DISPOSE */    /* long params[0];  // where const imports, __block storage references, etc. get laid down */};#if defined(__cplusplus)}#endif#endif /* _BLOCK_PRIVATE_H_ */