module ObjectSpace
The ObjectSpace module contains a number of routines that interact with the garbage collection facility and allow you to traverse all living objects with an iterator.
ObjectSpace also provides support for object finalizers, procs that will be called when a specific object is about to be destroyed by garbage collection.
include ObjectSpace a = "A" b = "B" c = "C" define_finalizer(a, proc {|id| puts "Finalizer one on #{id}" }) define_finalizer(a, proc {|id| puts "Finalizer two on #{id}" }) define_finalizer(b, proc {|id| puts "Finalizer three on #{id}" })
produces:
Finalizer three on 537763470 Finalizer one on 537763480 Finalizer two on 537763480
Public Class Methods
Converts an object id to a reference to the object. May not be called on an object id passed as a parameter to a finalizer.
s = "I am a string" #=> "I am a string" r = ObjectSpace._id2ref(s.object_id) #=> "I am a string" r == s #=> true
static VALUE
id2ref(VALUE obj, VALUE objid)
{
#if SIZEOF_LONG == SIZEOF_VOIDP
#define NUM2PTR(x) NUM2ULONG(x)
#elif SIZEOF_LONG_LONG == SIZEOF_VOIDP
#define NUM2PTR(x) NUM2ULL(x)
#endif
rb_objspace_t *objspace = &rb_objspace;
VALUE ptr;
void *p0;
rb_secure(4);
ptr = NUM2PTR(objid);
p0 = (void *)ptr;
if (ptr == Qtrue) return Qtrue;
if (ptr == Qfalse) return Qfalse;
if (ptr == Qnil) return Qnil;
if (FIXNUM_P(ptr)) return (VALUE)ptr;
if (FLONUM_P(ptr)) return (VALUE)ptr;
ptr = obj_id_to_ref(objid);
if ((ptr % sizeof(RVALUE)) == (4 << 2)) {
ID symid = ptr / sizeof(RVALUE);
if (rb_id2name(symid) == 0)
rb_raise(rb_eRangeError, "%p is not symbol id value", p0);
return ID2SYM(symid);
}
if (!is_id_value(objspace, ptr)) {
rb_raise(rb_eRangeError, "%p is not id value", p0);
}
if (!is_live_object(objspace, ptr)) {
rb_raise(rb_eRangeError, "%p is recycled object", p0);
}
return (VALUE)ptr;
}
Counts objects for each type.
It returns a hash, such as:
{
:TOTAL=>10000,
:FREE=>3011,
:T_OBJECT=>6,
:T_CLASS=>404,
# ...
}
The contents of the returned hash are implementation specific. It may be changed in future.
If the optional argument result_hash is given, it is
overwritten and returned. This is intended to avoid probe effect.
This method is only expected to work on C Ruby.
static VALUE
count_objects(int argc, VALUE *argv, VALUE os)
{
rb_objspace_t *objspace = &rb_objspace;
size_t counts[T_MASK+1];
size_t freed = 0;
size_t total = 0;
size_t i;
VALUE hash;
if (rb_scan_args(argc, argv, "01", &hash) == 1) {
if (!RB_TYPE_P(hash, T_HASH))
rb_raise(rb_eTypeError, "non-hash given");
}
for (i = 0; i <= T_MASK; i++) {
counts[i] = 0;
}
for (i = 0; i < heaps_used; i++) {
RVALUE *p, *pend;
p = objspace->heap.sorted[i]->start; pend = p + objspace->heap.sorted[i]->limit;
for (;p < pend; p++) {
if (p->as.basic.flags) {
counts[BUILTIN_TYPE(p)]++;
}
else {
freed++;
}
}
total += objspace->heap.sorted[i]->limit;
}
if (hash == Qnil) {
hash = rb_hash_new();
}
else if (!RHASH_EMPTY_P(hash)) {
st_foreach(RHASH_TBL(hash), set_zero, hash);
}
rb_hash_aset(hash, ID2SYM(rb_intern("TOTAL")), SIZET2NUM(total));
rb_hash_aset(hash, ID2SYM(rb_intern("FREE")), SIZET2NUM(freed));
for (i = 0; i <= T_MASK; i++) {
VALUE type;
switch (i) {
#define COUNT_TYPE(t) case (t): type = ID2SYM(rb_intern(#t)); break;
COUNT_TYPE(T_NONE);
COUNT_TYPE(T_OBJECT);
COUNT_TYPE(T_CLASS);
COUNT_TYPE(T_MODULE);
COUNT_TYPE(T_FLOAT);
COUNT_TYPE(T_STRING);
COUNT_TYPE(T_REGEXP);
COUNT_TYPE(T_ARRAY);
COUNT_TYPE(T_HASH);
COUNT_TYPE(T_STRUCT);
COUNT_TYPE(T_BIGNUM);
COUNT_TYPE(T_FILE);
COUNT_TYPE(T_DATA);
COUNT_TYPE(T_MATCH);
COUNT_TYPE(T_COMPLEX);
COUNT_TYPE(T_RATIONAL);
COUNT_TYPE(T_NIL);
COUNT_TYPE(T_TRUE);
COUNT_TYPE(T_FALSE);
COUNT_TYPE(T_SYMBOL);
COUNT_TYPE(T_FIXNUM);
COUNT_TYPE(T_UNDEF);
COUNT_TYPE(T_NODE);
COUNT_TYPE(T_ICLASS);
COUNT_TYPE(T_ZOMBIE);
#undef COUNT_TYPE
default: type = INT2NUM(i); break;
}
if (counts[i])
rb_hash_aset(hash, type, SIZET2NUM(counts[i]));
}
return hash;
}
Adds aProc as a finalizer, to be called after obj was destroyed.
static VALUE
define_final(int argc, VALUE *argv, VALUE os)
{
VALUE obj, block;
rb_scan_args(argc, argv, "11", &obj, &block);
rb_check_frozen(obj);
if (argc == 1) {
block = rb_block_proc();
}
else if (!rb_respond_to(block, rb_intern("call"))) {
rb_raise(rb_eArgError, "wrong type argument %s (should be callable)",
rb_obj_classname(block));
}
return define_final0(obj, block);
}
Calls the block once for each living, nonimmediate object in this Ruby
process. If module is specified, calls the block for only those
classes or modules that match (or are a subclass of) module.
Returns the number of objects found. Immediate objects
(Fixnums, Symbols true,
false, and nil) are never returned. In the
example below, each_object returns both the numbers we defined
and several constants defined in the Math module.
If no block is given, an enumerator is returned instead.
a = 102.7 b = 95 # Won't be returned c = 12345678987654321 count = ObjectSpace.each_object(Numeric) {|x| p x } puts "Total count: #{count}"
produces:
12345678987654321 102.7 2.71828182845905 3.14159265358979 2.22044604925031e-16 1.7976931348623157e+308 2.2250738585072e-308 Total count: 7
static VALUE
os_each_obj(int argc, VALUE *argv, VALUE os)
{
VALUE of;
rb_secure(4);
if (argc == 0) {
of = 0;
}
else {
rb_scan_args(argc, argv, "01", &of);
}
RETURN_ENUMERATOR(os, 1, &of);
return os_obj_of(of);
}
Initiates garbage collection, unless manually disabled.
VALUE
rb_gc_start(void)
{
rb_gc();
return Qnil;
}
Removes all finalizers for obj.
static VALUE
undefine_final(VALUE os, VALUE obj)
{
return rb_undefine_final(obj);
}