Class.c File Reference

#include "Config.h"
#include <assert.h>
#include <dlfcn.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "Class.h"
#include "Object.h"

Go to the source code of this file.

Functions
ident	_alloc (Class *clazz)
	Instantiate a type through the given Class.
ident	_cast (const Class *clazz, const ident obj)
	Perform a type-checking cast.
Class *	_initialize (const ClassDef *def)
	Initializes the given Class.
Class *	classForName (const char *name)
ident	release (ident obj)
	Atomically decrement the given Object's reference count. If the resulting reference count is 0, the Object is deallocated.
ident	retain (ident obj)
	Atomically increment the given Object's reference count.
static void	setup (void)
	Called when initializing Object to setup Objectively.
static void	teardown (void)
	Called atexit to teardown Objectively.

Variables
static Class *	_classes
size_t	_pageSize

Function Documentation

_alloc()

ident _alloc

(

Class *

clazz

)

Instantiate a type through the given Class.

Definition at line 123 of file Class.c.

                           {
 
  ident obj = calloc(1, clazz->def.instanceSize);
  assert(obj);
 
  Object *object = (Object *) obj;
 
  object->magic = OBJECTIVELY_MAGIC;
  object->clazz = clazz;
  object->referenceCount = 1;
 
  ident interface = clazz->interface;
  do {
    *(ident *) (obj + clazz->def.interfaceOffset) = interface;
  } while ((clazz = clazz->def.superclass));
 
  return obj;
}

_cast()

ident _cast	(	const Class *	clazz,
		const ident	obj
	)

Perform a type-checking cast.

Definition at line 142 of file Class.c.

                                                 {
 
  if (obj) {
    const Class *c = ((Object *) obj)->clazz;
    while (c) {
 
      // as a special case, we optimize for _Object
      if (c == clazz || clazz == _Object()) {
        break;
      }
 
      c = c->def.superclass;
    }
    assert(c);
  }
 
  return (ident) obj;
}

_initialize()

Class * _initialize

(

const ClassDef *

clazz

)

Initializes the given Class.

Parameters

clazz

The Class descriptor.

Returns

The initialized Class.

Definition at line 86 of file Class.c.

                                        {
 
  static Once once;
  do_once(&once, setup());
 
  assert(def);
  assert(def->name);
  assert(def->instanceSize);
  assert(def->interfaceSize);
  assert(def->interfaceOffset);
 
  Class *clazz = calloc(1, sizeof(Class));
  assert(clazz);
 
  clazz->def = *def;
 
  clazz->interface = calloc(1, def->interfaceSize);
  assert(clazz->interface);
 
  Class *superclass = clazz->def.superclass;
  if (superclass) {
 
    assert(superclass->def.instanceSize <= def->instanceSize);
    assert(superclass->def.interfaceSize <= def->interfaceSize);
 
    memcpy(clazz->interface, superclass->interface, superclass->def.interfaceSize);
  }
 
  if (clazz->def.initialize) {
    clazz->def.initialize(clazz);
  }
 
  clazz->next = __sync_lock_test_and_set(&_classes, clazz);
 
  return clazz;
}

classForName()

Class * classForName

(

const char *

name

)

Returns

The Class with the given name, or NULL if no such Class has been initialized.

Definition at line 161 of file Class.c.

                                      {
 
  if (name) {
    Class *c = _classes;
    while (c) {
      if (strcmp(name, c->def.name) == 0) {
        return c;
      }
      c = c->next;
    }
 
    char *s;
    if (asprintf(&s, "_%s", name) > 0) {
      Class *clazz = NULL;
#if defined(_WIN32)
      static Once once;
      static ident handle;
      do_once(&once, { handle = dlopen(NULL, RTLD_LAZY); });
      Class *(*archetype)(void) = handle ? dlsym(handle, s) : NULL;
#else
      Class *(*archetype)(void) = dlsym(RTLD_DEFAULT, s);
#endif
      if (archetype) {
        clazz = archetype();
      }
 
      free(s);
      return clazz;
    }
  }
 
  return NULL;
}

release()

ident release

(

ident

obj

)

Atomically decrement the given Object's reference count. If the resulting reference count is 0, the Object is deallocated.

Returns

This function always returns NULL.

Definition at line 195 of file Class.c.

                         {
 
  if (obj) {
    Object *object = cast(Object, obj);
 
    assert(object);
 
    if (__sync_add_and_fetch(&object->referenceCount, -1) == 0) {
      $(object, dealloc);
    }
  }
 
  return NULL;
}

retain()

ident retain

(

ident

obj

)

Atomically increment the given Object's reference count.

Returns

The Object.

Remarks

By calling this, the caller is expressing ownership of the Object, and preventing it from being released. Be sure to balance calls to retain with calls to release.

Definition at line 210 of file Class.c.

                        {
 
  Object *object = cast(Object, obj);
 
  assert(object);
 
  __sync_add_and_fetch(&object->referenceCount, 1);
 
  return obj;
}

setup()

static void setup ( void  )

static

Called when initializing Object to setup Objectively.

Definition at line 73 of file Class.c.

                        {
 
  _classes = NULL;
 
#if !defined(_SC_PAGESIZE)
  _pageSize = 4096;
#else
  _pageSize = sysconf(_SC_PAGESIZE);
#endif
 
  atexit(teardown);
}

teardown()

static void teardown ( void  )

static

Called atexit to teardown Objectively.

Definition at line 46 of file Class.c.

                           {
  Class *c;
 
  c = _classes;
  while (c) {
    if (c->def.destroy) {
      c->def.destroy(c);
    }
 
    c = c->next;
  }
 
  c = _classes;
  while (c) {
 
    Class *next = c->next;
 
    free(c->interface);
    free(c);
 
    c = next;
  }
}

Variable Documentation

_classes

Class* _classes

static

Definition at line 41 of file Class.c.

_pageSize

size_t _pageSize

Definition at line 39 of file Class.c.