Module: ObjectSpace (Ruby 2.2.2)
Description: Module : ObjectSpace - Ruby 2.2.2

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Support for the Ruby 2.2 series has ended. See here for reference.

### Home Classes Methods

### In Files

- objspace/object_tracing.c
- objspace/objspace.c
- objspace/objspace_dump.c

### Namespace

- CLASS ObjectSpace::InternalObjectWrapper

### Methods

- ::allocation_class_path
- ::allocation_generation
- ::allocation_method_id
- ::allocation_sourcefile
- ::allocation_sourceline
- ::count_nodes
- ::count_objects_size
- ::count_tdata_objects
- ::dump
- ::dump_all
- ::memsize_of
- ::memsize_of_all
- ::reachable_objects_from
- ::reachable_objects_from_root
- ::trace_object_allocations
- ::trace_object_allocations_clear
- ::trace_object_allocations_debug_start
- ::trace_object_allocations_start
- ::trace_object_allocations_stop

### Class/Module Index

Quicksearch

- ObjectSpace
- ObjectSpace::InternalObjectWrapper

No matching classes.

# ObjectSpace

The objspace library extends the ObjectSpace module and adds several methods to get internal statistic information about object/memory management.

You need to `require 'objspace'` to use this extension module.

Generally, you *SHOULD NOT* use this library if you do not know about the MRI implementation. Mainly, this library is for (memory) profiler developers and MRI developers who need to know about MRI memory usage.

### Public Class Methods

allocation_class_path(object) → string click to toggle source

Returns the class for the given `object`.

    class A
      def foo
        ObjectSpace::trace_object_allocations do
          obj = Object.new
          p "#{ObjectSpace::allocation_class_path(obj)}"
        end
      end
    end

    A.new.foo #=> "Class"

See ::trace_object_allocations for more information and examples.

                   static VALUE
    allocation_class_path(VALUE self, VALUE obj)
    {
        struct allocation_info *info = lookup_allocation_info(obj);

        if (info && info->class_path) {
            return rb_str_new2(info->class_path);
        }
        else {
            return Qnil;
        }
    }

allocation_generation(object) → Fixnum click to toggle source

Returns garbage collector generation for the given `object`.

    class B
      include ObjectSpace

      def foo
        trace_object_allocations do
          obj = Object.new
          p "Generation is #{allocation_generation(obj)}"
        end
      end
    end

    B.new.foo #=> "Generation is 3"

See ::trace_object_allocations for more information and examples.

                   static VALUE
    allocation_generation(VALUE self, VALUE obj)
    {
        struct allocation_info *info = lookup_allocation_info(obj);
        if (info) {
            return SIZET2NUM(info->generation);
        }
        else {
            return Qnil;
        }
    }

allocation_method_id(object) → string click to toggle source

Returns the method identifier for the given `object`.

    class A
      include ObjectSpace

      def foo
        trace_object_allocations do
          obj = Object.new
          p "#{allocation_class_path(obj)}##{allocation_method_id(obj)}"
        end
      end
    end

    A.new.foo #=> "Class#new"

See ::trace_object_allocations for more information and examples.

                   static VALUE
    allocation_method_id(VALUE self, VALUE obj)
    {
        struct allocation_info *info = lookup_allocation_info(obj);
        if (info) {
            return info->mid;
        }
        else {
            return Qnil;
        }
    }

allocation_sourcefile(object) → string click to toggle source

Returns the source file origin from the given `object`.

See ::trace_object_allocations for more information and examples.

                   static VALUE
    allocation_sourcefile(VALUE self, VALUE obj)
    {
        struct allocation_info *info = lookup_allocation_info(obj);

        if (info && info->path) {
            return rb_str_new2(info->path);
        }
        else {
            return Qnil;
        }
    }

allocation_sourceline(object) → string click to toggle source

Returns the original line from source for from the given `object`.

See ::trace_object_allocations for more information and examples.

                   static VALUE
    allocation_sourceline(VALUE self, VALUE obj)
    {
        struct allocation_info *info = lookup_allocation_info(obj);

        if (info) {
            return INT2FIX(info->line);
        }
        else {
            return Qnil;
        }
    }

count_nodes([result_hash]) → hash click to toggle source

Counts nodes for each node type.

This method is only for MRI developers interested in performance and memory usage of Ruby programs.

It returns a hash as:

    {:NODE_METHOD=>2027, :NODE_FBODY=>1927, :NODE_CFUNC=>1798, ...}

If the optional argument, result_hash, is given, it is overwritten and returned. This is intended to avoid probe effect.

Note: The contents of the returned hash is implementation defined. It may be changed in future.

This method is only expected to work with C Ruby.

                   static VALUE
    count_nodes(int argc, VALUE *argv, VALUE os)
    {
        size_t nodes[NODE_LAST+1];
        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 <= NODE_LAST; i++) {
            nodes[i] = 0;
        }

        rb_objspace_each_objects(cn_i, &nodes[0]);

        if (hash == Qnil) {
            hash = rb_hash_new();
        }
        else if (!RHASH_EMPTY_P(hash)) {
            st_foreach(RHASH_TBL(hash), set_zero_i, hash);
        }

        for (i=0; i<NODE_LAST; i++) {
            if (nodes[i] != 0) {
                VALUE node;
                switch (i) {
    #define COUNT_NODE(n) case n: node = ID2SYM(rb_intern(#n)); break;
                    COUNT_NODE(NODE_SCOPE);
                    COUNT_NODE(NODE_BLOCK);
                    COUNT_NODE(NODE_IF);
                    COUNT_NODE(NODE_CASE);
                    COUNT_NODE(NODE_WHEN);
                    COUNT_NODE(NODE_OPT_N);
                    COUNT_NODE(NODE_WHILE);
                    COUNT_NODE(NODE_UNTIL);
                    COUNT_NODE(NODE_ITER);
                    COUNT_NODE(NODE_FOR);
                    COUNT_NODE(NODE_BREAK);
                    COUNT_NODE(NODE_NEXT);
                    COUNT_NODE(NODE_REDO);
                    COUNT_NODE(NODE_RETRY);
                    COUNT_NODE(NODE_BEGIN);
                    COUNT_NODE(NODE_RESCUE);
                    COUNT_NODE(NODE_RESBODY);
                    COUNT_NODE(NODE_ENSURE);
                    COUNT_NODE(NODE_AND);
                    COUNT_NODE(NODE_OR);
                    COUNT_NODE(NODE_MASGN);
                    COUNT_NODE(NODE_LASGN);
                    COUNT_NODE(NODE_DASGN);
                    COUNT_NODE(NODE_DASGN_CURR);
                    COUNT_NODE(NODE_GASGN);
                    COUNT_NODE(NODE_IASGN);
                    COUNT_NODE(NODE_IASGN2);
                    COUNT_NODE(NODE_CDECL);
                    COUNT_NODE(NODE_CVASGN);
                    COUNT_NODE(NODE_CVDECL);
                    COUNT_NODE(NODE_OP_ASGN1);
                    COUNT_NODE(NODE_OP_ASGN2);
                    COUNT_NODE(NODE_OP_ASGN_AND);
                    COUNT_NODE(NODE_OP_ASGN_OR);
                    COUNT_NODE(NODE_OP_CDECL);
                    COUNT_NODE(NODE_CALL);
                    COUNT_NODE(NODE_FCALL);
                    COUNT_NODE(NODE_VCALL);
                    COUNT_NODE(NODE_SUPER);
                    COUNT_NODE(NODE_ZSUPER);
                    COUNT_NODE(NODE_ARRAY);
                    COUNT_NODE(NODE_ZARRAY);
                    COUNT_NODE(NODE_VALUES);
                    COUNT_NODE(NODE_HASH);
                    COUNT_NODE(NODE_RETURN);
                    COUNT_NODE(NODE_YIELD);
                    COUNT_NODE(NODE_LVAR);
                    COUNT_NODE(NODE_DVAR);
                    COUNT_NODE(NODE_GVAR);
                    COUNT_NODE(NODE_IVAR);
                    COUNT_NODE(NODE_CONST);
                    COUNT_NODE(NODE_CVAR);
                    COUNT_NODE(NODE_NTH_REF);
                    COUNT_NODE(NODE_BACK_REF);
                    COUNT_NODE(NODE_MATCH);
                    COUNT_NODE(NODE_MATCH2);
                    COUNT_NODE(NODE_MATCH3);
                    COUNT_NODE(NODE_LIT);
                    COUNT_NODE(NODE_STR);
                    COUNT_NODE(NODE_DSTR);
                    COUNT_NODE(NODE_XSTR);
                    COUNT_NODE(NODE_DXSTR);
                    COUNT_NODE(NODE_EVSTR);
                    COUNT_NODE(NODE_DREGX);
                    COUNT_NODE(NODE_DREGX_ONCE);
                    COUNT_NODE(NODE_ARGS);
                    COUNT_NODE(NODE_ARGS_AUX);
                    COUNT_NODE(NODE_OPT_ARG);
                    COUNT_NODE(NODE_KW_ARG);
                    COUNT_NODE(NODE_POSTARG);
                    COUNT_NODE(NODE_ARGSCAT);
                    COUNT_NODE(NODE_ARGSPUSH);
                    COUNT_NODE(NODE_SPLAT);
                    COUNT_NODE(NODE_TO_ARY);
                    COUNT_NODE(NODE_BLOCK_ARG);
                    COUNT_NODE(NODE_BLOCK_PASS);
                    COUNT_NODE(NODE_DEFN);
                    COUNT_NODE(NODE_DEFS);
                    COUNT_NODE(NODE_ALIAS);
                    COUNT_NODE(NODE_VALIAS);
                    COUNT_NODE(NODE_UNDEF);
                    COUNT_NODE(NODE_CLASS);
                    COUNT_NODE(NODE_MODULE);
                    COUNT_NODE(NODE_SCLASS);
                    COUNT_NODE(NODE_COLON2);
                    COUNT_NODE(NODE_COLON3);
                    COUNT_NODE(NODE_CREF);
                    COUNT_NODE(NODE_DOT2);
                    COUNT_NODE(NODE_DOT3);
                    COUNT_NODE(NODE_FLIP2);
                    COUNT_NODE(NODE_FLIP3);
                    COUNT_NODE(NODE_SELF);
                    COUNT_NODE(NODE_NIL);
                    COUNT_NODE(NODE_TRUE);
                    COUNT_NODE(NODE_FALSE);
                    COUNT_NODE(NODE_ERRINFO);
                    COUNT_NODE(NODE_DEFINED);
                    COUNT_NODE(NODE_POSTEXE);
                    COUNT_NODE(NODE_ALLOCA);
                    COUNT_NODE(NODE_BMETHOD);
                    COUNT_NODE(NODE_MEMO);
                    COUNT_NODE(NODE_IFUNC);
                    COUNT_NODE(NODE_DSYM);
                    COUNT_NODE(NODE_ATTRASGN);
                    COUNT_NODE(NODE_PRELUDE);
                    COUNT_NODE(NODE_LAMBDA);
    #undef COUNT_NODE
                  default: node = INT2FIX(i);
                }
                rb_hash_aset(hash, node, SIZET2NUM(nodes[i]));
            }
        }
        return hash;
    }

count_objects_size([result_hash]) → hash click to toggle source

Counts objects size (in bytes) for each type.

Note that this information is incomplete. You need to deal with this information as only a HINT. Especially, total size of T_DATA may not right size.

It returns a hash as:

    {:TOTAL=>1461154, :T_CLASS=>158280, :T_MODULE=>20672, :T_STRING=>527249, ...}

If the optional argument, result_hash, is given, it is overwritten and returned. This is intended to avoid probe effect.

The contents of the returned hash is implementation defined. It may be changed in future.

This method is only expected to work with C Ruby.

                   static VALUE
    count_objects_size(int argc, VALUE *argv, VALUE os)
    {
        size_t counts[T_MASK+1];
        size_t total = 0;
        enum ruby_value_type 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;
        }

        rb_objspace_each_objects(cos_i, &counts[0]);

        if (hash == Qnil) {
            hash = rb_hash_new();
        }
        else if (!RHASH_EMPTY_P(hash)) {
            st_foreach(RHASH_TBL(hash), set_zero_i, hash);
        }

        for (i = 0; i <= T_MASK; i++) {
            if (counts[i]) {
                VALUE type = type2sym(i);
                total += counts[i];
                rb_hash_aset(hash, type, SIZET2NUM(counts[i]));
            }
        }
        rb_hash_aset(hash, ID2SYM(rb_intern("TOTAL")), SIZET2NUM(total));
        return hash;
    }

count_tdata_objects([result_hash]) → hash click to toggle source

Counts objects for each `T_DATA` type.

This method is only for MRI developers interested in performance and memory usage of Ruby programs.

It returns a hash as:

    {RubyVM::InstructionSequence=>504, :parser=>5, :barrier=>6,
     :mutex=>6, Proc=>60, RubyVM::Env=>57, Mutex=>1, Encoding=>99,
     ThreadGroup=>1, Binding=>1, Thread=>1, RubyVM=>1, :iseq=>1,
     Random=>1, ARGF.class=>1, Data=>1, :autoload=>3, Time=>2}
    # T_DATA objects existing at startup on r32276.

If the optional argument, result_hash, is given, it is overwritten and returned. This is intended to avoid probe effect.

The contents of the returned hash is implementation specific and may change in the future.

In this version, keys are Class object or Symbol object.

If object is kind of normal (accessible) object, the key is Class object. If object is not a kind of normal (internal) object, the key is symbol name, registered by rb_data_type_struct.

This method is only expected to work with C Ruby.

                   static VALUE
    count_tdata_objects(int argc, VALUE *argv, VALUE self)
    {
        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");
        }

        if (hash == Qnil) {
            hash = rb_hash_new();
        }
        else if (!RHASH_EMPTY_P(hash)) {
            st_foreach(RHASH_TBL(hash), set_zero_i, hash);
        }

        rb_objspace_each_objects(cto_i, (void *)hash);

        return hash;
    }

dump(obj[, output: :string]) # => "{ ... }" click to toggle source
dump(obj, output: :file) # => #
dump(obj, output: :stdout) # => nil

Dump the contents of a ruby object as JSON.

This method is only expected to work with C Ruby. This is an experimental method and is subject to change. In particular, the function signature and output format are not guaranteed to be compatible in future versions of ruby.

                   static VALUE
    objspace_dump(int argc, VALUE *argv, VALUE os)
    {
        static const char filename[] = "rubyobj";
        VALUE obj = Qnil, opts = Qnil, output;
        struct dump_config dc = {0,};

        rb_scan_args(argc, argv, "1:", &obj, &opts);

        output = dump_output(&dc, opts, sym_string, filename);

        dump_object(obj, &dc);

        return dump_result(&dc, output);
    }

dump_all([output: :file]) # => # click to toggle source
dump_all(output: :stdout) # => nil
dump_all(output: :string) # => "{...}\n{...}\n..."
dump_all(output:
open('heap.json','w')) # => #

Dump the contents of the ruby heap as JSON.

This method is only expected to work with C Ruby. This is an experimental method and is subject to change. In particular, the function signature and output format are not guaranteed to be compatible in future versions of ruby.

                   static VALUE
    objspace_dump_all(int argc, VALUE *argv, VALUE os)
    {
        static const char filename[] = "rubyheap";
        VALUE opts = Qnil, output;
        struct dump_config dc = {0,};

        rb_scan_args(argc, argv, "0:", &opts);

        output = dump_output(&dc, opts, sym_file, filename);

        /* dump roots */
        rb_objspace_reachable_objects_from_root(root_obj_i, &dc);
        if (dc.roots) dump_append(&dc, "]}\n");

        /* dump all objects */
        rb_objspace_each_objects(heap_i, &dc);

        return dump_result(&dc, output);
    }

memsize_of(obj) → Integer click to toggle source

Return consuming memory size of obj.

Note that the return size is incomplete. You need to deal with this information as only a HINT. Especially, the size of `T_DATA` may not be correct.

This method is only expected to work with C Ruby.

From Ruby 2.2, ::memsize_of(obj) returns a memory size includes sizeof(RVALUE).

                   static VALUE
    memsize_of_m(VALUE self, VALUE obj)
    {
        return SIZET2NUM(rb_obj_memsize_of(obj));
    }

memsize_of_all([klass]) → Integer click to toggle source

Return consuming memory size of all living objects.

If `klass` (should be Class object) is given, return the total memory size of instances of the given class.

Note that the returned size is incomplete. You need to deal with this information as only a HINT. Especially, the size of `T_DATA` may not be correct.

Note that this method does NOT return total malloc'ed memory size.

This method can be defined by the following Ruby code:

    def memsize_of_all klass = false
      total = 0
      ObjectSpace.each_object{|e|
        total += ObjectSpace.memsize_of(e) if klass == false || e.kind_of?(klass)
      }
      total
    end

This method is only expected to work with C Ruby.

                   static VALUE
    memsize_of_all_m(int argc, VALUE *argv, VALUE self)
    {
        struct total_data data = {0, 0};

        if (argc > 0) {
            rb_scan_args(argc, argv, "01", &data.klass);
        }

        rb_objspace_each_objects(total_i, &data);
        return SIZET2NUM(data.total);
    }

reachable_objects_from(obj) → array or nil click to toggle source

MRI specific feature

  Return all reachable objects from `obj'.

This method returns all reachable objects from `obj'.

If `obj' has two or more references to the same object `x', then returned array only includes one `x' object.

If `obj' is a non-markable (non-heap management) object such as true, false, nil, symbols and Fixnums (and Flonum) then it simply returns nil.

If `obj' has references to an internal object, then it returns instances of ObjectSpace::InternalObjectWrapper class. This object contains a reference to an internal object and you can check the type of internal object with `type' method.

If `obj' is instance of ObjectSpace::InternalObjectWrapper class, then this method returns all reachable object from an internal object, which is pointed by `obj'.

With this method, you can find memory leaks.

This method is only expected to work except with C Ruby.

Example:

    ObjectSpace.reachable_objects_from(['a', 'b', 'c'])
    #=> [Array, 'a', 'b', 'c']

    ObjectSpace.reachable_objects_from(['a', 'a', 'a'])
    #=> [Array, 'a', 'a', 'a'] # all 'a' strings have different object id

    ObjectSpace.reachable_objects_from([v = 'a', v, v])
    #=> [Array, 'a']

    ObjectSpace.reachable_objects_from(1)
    #=> nil # 1 is not markable (heap managed) object

                   static VALUE
    reachable_objects_from(VALUE self, VALUE obj)
    {
        if (rb_objspace_markable_object_p(obj)) {
            VALUE ret = rb_ary_new();
            struct rof_data data;

            if (rb_typeddata_is_kind_of(obj, &iow_data_type)) {
                obj = (VALUE)DATA_PTR(obj);
            }

            data.refs = st_init_numtable();
            data.internals = rb_ary_new();

            rb_objspace_reachable_objects_from(obj, reachable_object_from_i, &data);

            st_foreach(data.refs, collect_values, (st_data_t)ret);
            return ret;
        }
        else {
            return Qnil;
        }
    }

reachable_objects_from_root → hash click to toggle source

MRI specific feature

  Return all reachable objects from root.

                   static VALUE
    reachable_objects_from_root(VALUE self)
    {
        struct rofr_data data;
        VALUE hash = data.categories = rb_hash_new();
        data.last_category = 0;

        rb_funcall(hash, rb_intern("compare_by_identity"), 0);
        rb_objspace_reachable_objects_from_root(reachable_object_from_root_i, &data);
        rb_hash_foreach(hash, collect_values_of_values, hash);

        return hash;
    }

trace_object_allocations { block } click to toggle source

Starts tracing object allocations from the ObjectSpace extension module.

For example:

    require 'objspace'

    class C
      include ObjectSpace

      def foo
        trace_object_allocations do
          obj = Object.new
          p "#{allocation_sourcefile(obj)}:#{allocation_sourceline(obj)}"
        end
      end
    end

    C.new.foo #=> "objtrace.rb:8"

This example has included the ObjectSpace module to make it easier to read, but you can also use the ::trace_object_allocations notation (recommended).

Note that this feature introduces a huge performance decrease and huge memory consumption.

                   static VALUE
    trace_object_allocations(VALUE self)
    {
        trace_object_allocations_start(self);
        return rb_ensure(rb_yield, Qnil, trace_object_allocations_stop, self);
    }

trace_object_allocations_clear click to toggle source

Clear recorded tracing information.

                   static VALUE
    trace_object_allocations_clear(VALUE self)
    {
        struct traceobj_arg *arg = get_traceobj_arg();

        /* clear tables */
        st_foreach(arg->object_table, free_values_i, 0);
        st_clear(arg->object_table);
        st_foreach(arg->str_table, free_keys_i, 0);
        st_clear(arg->str_table);

        /* do not touch TracePoints */

        return Qnil;
    }

trace_object_allocations_debug_start() click to toggle source

                   static VALUE
    trace_object_allocations_debug_start(VALUE self)
    {
        tmp_keep_remains = 1;
        if (object_allocations_reporter_registered == 0) {
            object_allocations_reporter_registered = 1;
            rb_bug_reporter_add(object_allocations_reporter, 0);
        }

        return trace_object_allocations_start(self);
    }

trace_object_allocations_start click to toggle source

Starts tracing object allocations.

                   static VALUE
    trace_object_allocations_start(VALUE self)
    {
        struct traceobj_arg *arg = get_traceobj_arg();

        if (arg->running++ > 0) {
            /* do nothing */
        }
        else {
            if (arg->newobj_trace == 0) {
                arg->newobj_trace = rb_tracepoint_new(0, RUBY_INTERNAL_EVENT_NEWOBJ, newobj_i, arg);
                arg->freeobj_trace = rb_tracepoint_new(0, RUBY_INTERNAL_EVENT_FREEOBJ, freeobj_i, arg);
            }
            rb_tracepoint_enable(arg->newobj_trace);
            rb_tracepoint_enable(arg->freeobj_trace);
        }

        return Qnil;
    }

trace_object_allocations_stop click to toggle source

Stop tracing object allocations.

Note that if ::trace_object_allocations_start is called n-times, then tracing will stop after calling ::trace_object_allocations_stop n-times.

                   static VALUE
    trace_object_allocations_stop(VALUE self)
    {
        struct traceobj_arg *arg = get_traceobj_arg();

        if (arg->running > 0) {
            arg->running--;
        }

        if (arg->running == 0) {
            rb_tracepoint_disable(arg->newobj_trace);
            rb_tracepoint_disable(arg->freeobj_trace);
            arg->newobj_trace = 0;
            arg->freeobj_trace = 0;
        }

        return Qnil;
    }