Expose rb_str_chilled_p

Some extensions (like stringio) may need to differentiate between
chilled strings and frozen strings.

They can now use rb_str_chilled_p but must check for its presence since
the function will be removed when chilled strings are removed.

[Bug #20389]

[Feature #20205]

Co-authored-by: Jean Boussier <byroot@ruby-lang.org>

ext/-test-/string/chilled.c

@@ -0,0 +1,13 @@
+#include "ruby.h"
+
+static VALUE
+bug_s_rb_str_chilled_p(VALUE self, VALUE str)
+{
+    return rb_str_chilled_p(str) ? Qtrue : Qfalse;
+}
+
+void
+Init_string_chilled(VALUE klass)
+{
+    rb_define_singleton_method(klass, "rb_str_chilled_p", bug_s_rb_str_chilled_p, 1);
+}

ext/-test-/string/depend

@@ -173,6 +173,165 @@ capacity.o: $(hdrdir)/ruby/subst.h
 capacity.o: $(top_srcdir)/internal/compilers.h
 capacity.o: $(top_srcdir)/internal/string.h
 capacity.o: capacity.c
+chilled.o: $(RUBY_EXTCONF_H)
+chilled.o: $(arch_hdrdir)/ruby/config.h
+chilled.o: $(hdrdir)/ruby.h
+chilled.o: $(hdrdir)/ruby/assert.h
+chilled.o: $(hdrdir)/ruby/backward.h
+chilled.o: $(hdrdir)/ruby/backward/2/assume.h
+chilled.o: $(hdrdir)/ruby/backward/2/attributes.h
+chilled.o: $(hdrdir)/ruby/backward/2/bool.h
+chilled.o: $(hdrdir)/ruby/backward/2/inttypes.h
+chilled.o: $(hdrdir)/ruby/backward/2/limits.h
+chilled.o: $(hdrdir)/ruby/backward/2/long_long.h
+chilled.o: $(hdrdir)/ruby/backward/2/stdalign.h
+chilled.o: $(hdrdir)/ruby/backward/2/stdarg.h
+chilled.o: $(hdrdir)/ruby/defines.h
+chilled.o: $(hdrdir)/ruby/intern.h
+chilled.o: $(hdrdir)/ruby/internal/abi.h
+chilled.o: $(hdrdir)/ruby/internal/anyargs.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/char.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/double.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/fixnum.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/gid_t.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/int.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/intptr_t.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/long.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/long_long.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/mode_t.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/off_t.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/pid_t.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/short.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/size_t.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/st_data_t.h
+chilled.o: $(hdrdir)/ruby/internal/arithmetic/uid_t.h
+chilled.o: $(hdrdir)/ruby/internal/assume.h
+chilled.o: $(hdrdir)/ruby/internal/attr/alloc_size.h
+chilled.o: $(hdrdir)/ruby/internal/attr/artificial.h
+chilled.o: $(hdrdir)/ruby/internal/attr/cold.h
+chilled.o: $(hdrdir)/ruby/internal/attr/const.h
+chilled.o: $(hdrdir)/ruby/internal/attr/constexpr.h
+chilled.o: $(hdrdir)/ruby/internal/attr/deprecated.h
+chilled.o: $(hdrdir)/ruby/internal/attr/diagnose_if.h
+chilled.o: $(hdrdir)/ruby/internal/attr/enum_extensibility.h
+chilled.o: $(hdrdir)/ruby/internal/attr/error.h
+chilled.o: $(hdrdir)/ruby/internal/attr/flag_enum.h
+chilled.o: $(hdrdir)/ruby/internal/attr/forceinline.h
+chilled.o: $(hdrdir)/ruby/internal/attr/format.h
+chilled.o: $(hdrdir)/ruby/internal/attr/maybe_unused.h
+chilled.o: $(hdrdir)/ruby/internal/attr/noalias.h
+chilled.o: $(hdrdir)/ruby/internal/attr/nodiscard.h
+chilled.o: $(hdrdir)/ruby/internal/attr/noexcept.h
+chilled.o: $(hdrdir)/ruby/internal/attr/noinline.h
+chilled.o: $(hdrdir)/ruby/internal/attr/nonnull.h
+chilled.o: $(hdrdir)/ruby/internal/attr/noreturn.h
+chilled.o: $(hdrdir)/ruby/internal/attr/packed_struct.h
+chilled.o: $(hdrdir)/ruby/internal/attr/pure.h
+chilled.o: $(hdrdir)/ruby/internal/attr/restrict.h
+chilled.o: $(hdrdir)/ruby/internal/attr/returns_nonnull.h
+chilled.o: $(hdrdir)/ruby/internal/attr/warning.h
+chilled.o: $(hdrdir)/ruby/internal/attr/weakref.h
+chilled.o: $(hdrdir)/ruby/internal/cast.h
+chilled.o: $(hdrdir)/ruby/internal/compiler_is.h
+chilled.o: $(hdrdir)/ruby/internal/compiler_is/apple.h
+chilled.o: $(hdrdir)/ruby/internal/compiler_is/clang.h
+chilled.o: $(hdrdir)/ruby/internal/compiler_is/gcc.h
+chilled.o: $(hdrdir)/ruby/internal/compiler_is/intel.h
+chilled.o: $(hdrdir)/ruby/internal/compiler_is/msvc.h
+chilled.o: $(hdrdir)/ruby/internal/compiler_is/sunpro.h
+chilled.o: $(hdrdir)/ruby/internal/compiler_since.h
+chilled.o: $(hdrdir)/ruby/internal/config.h
+chilled.o: $(hdrdir)/ruby/internal/constant_p.h
+chilled.o: $(hdrdir)/ruby/internal/core.h
+chilled.o: $(hdrdir)/ruby/internal/core/rarray.h
+chilled.o: $(hdrdir)/ruby/internal/core/rbasic.h
+chilled.o: $(hdrdir)/ruby/internal/core/rbignum.h
+chilled.o: $(hdrdir)/ruby/internal/core/rclass.h
+chilled.o: $(hdrdir)/ruby/internal/core/rdata.h
+chilled.o: $(hdrdir)/ruby/internal/core/rfile.h
+chilled.o: $(hdrdir)/ruby/internal/core/rhash.h
+chilled.o: $(hdrdir)/ruby/internal/core/robject.h
+chilled.o: $(hdrdir)/ruby/internal/core/rregexp.h
+chilled.o: $(hdrdir)/ruby/internal/core/rstring.h
+chilled.o: $(hdrdir)/ruby/internal/core/rstruct.h
+chilled.o: $(hdrdir)/ruby/internal/core/rtypeddata.h
+chilled.o: $(hdrdir)/ruby/internal/ctype.h
+chilled.o: $(hdrdir)/ruby/internal/dllexport.h
+chilled.o: $(hdrdir)/ruby/internal/dosish.h
+chilled.o: $(hdrdir)/ruby/internal/error.h
+chilled.o: $(hdrdir)/ruby/internal/eval.h
+chilled.o: $(hdrdir)/ruby/internal/event.h
+chilled.o: $(hdrdir)/ruby/internal/fl_type.h
+chilled.o: $(hdrdir)/ruby/internal/gc.h
+chilled.o: $(hdrdir)/ruby/internal/glob.h
+chilled.o: $(hdrdir)/ruby/internal/globals.h
+chilled.o: $(hdrdir)/ruby/internal/has/attribute.h
+chilled.o: $(hdrdir)/ruby/internal/has/builtin.h
+chilled.o: $(hdrdir)/ruby/internal/has/c_attribute.h
+chilled.o: $(hdrdir)/ruby/internal/has/cpp_attribute.h
+chilled.o: $(hdrdir)/ruby/internal/has/declspec_attribute.h
+chilled.o: $(hdrdir)/ruby/internal/has/extension.h
+chilled.o: $(hdrdir)/ruby/internal/has/feature.h
+chilled.o: $(hdrdir)/ruby/internal/has/warning.h
+chilled.o: $(hdrdir)/ruby/internal/intern/array.h
+chilled.o: $(hdrdir)/ruby/internal/intern/bignum.h
+chilled.o: $(hdrdir)/ruby/internal/intern/class.h
+chilled.o: $(hdrdir)/ruby/internal/intern/compar.h
+chilled.o: $(hdrdir)/ruby/internal/intern/complex.h
+chilled.o: $(hdrdir)/ruby/internal/intern/cont.h
+chilled.o: $(hdrdir)/ruby/internal/intern/dir.h
+chilled.o: $(hdrdir)/ruby/internal/intern/enum.h
+chilled.o: $(hdrdir)/ruby/internal/intern/enumerator.h
+chilled.o: $(hdrdir)/ruby/internal/intern/error.h
+chilled.o: $(hdrdir)/ruby/internal/intern/eval.h
+chilled.o: $(hdrdir)/ruby/internal/intern/file.h
+chilled.o: $(hdrdir)/ruby/internal/intern/hash.h
+chilled.o: $(hdrdir)/ruby/internal/intern/io.h
+chilled.o: $(hdrdir)/ruby/internal/intern/load.h
+chilled.o: $(hdrdir)/ruby/internal/intern/marshal.h
+chilled.o: $(hdrdir)/ruby/internal/intern/numeric.h
+chilled.o: $(hdrdir)/ruby/internal/intern/object.h
+chilled.o: $(hdrdir)/ruby/internal/intern/parse.h
+chilled.o: $(hdrdir)/ruby/internal/intern/proc.h
+chilled.o: $(hdrdir)/ruby/internal/intern/process.h
+chilled.o: $(hdrdir)/ruby/internal/intern/random.h
+chilled.o: $(hdrdir)/ruby/internal/intern/range.h
+chilled.o: $(hdrdir)/ruby/internal/intern/rational.h
+chilled.o: $(hdrdir)/ruby/internal/intern/re.h
+chilled.o: $(hdrdir)/ruby/internal/intern/ruby.h
+chilled.o: $(hdrdir)/ruby/internal/intern/select.h
+chilled.o: $(hdrdir)/ruby/internal/intern/select/largesize.h
+chilled.o: $(hdrdir)/ruby/internal/intern/signal.h
+chilled.o: $(hdrdir)/ruby/internal/intern/sprintf.h
+chilled.o: $(hdrdir)/ruby/internal/intern/string.h
+chilled.o: $(hdrdir)/ruby/internal/intern/struct.h
+chilled.o: $(hdrdir)/ruby/internal/intern/thread.h
+chilled.o: $(hdrdir)/ruby/internal/intern/time.h
+chilled.o: $(hdrdir)/ruby/internal/intern/variable.h
+chilled.o: $(hdrdir)/ruby/internal/intern/vm.h
+chilled.o: $(hdrdir)/ruby/internal/interpreter.h
+chilled.o: $(hdrdir)/ruby/internal/iterator.h
+chilled.o: $(hdrdir)/ruby/internal/memory.h
+chilled.o: $(hdrdir)/ruby/internal/method.h
+chilled.o: $(hdrdir)/ruby/internal/module.h
+chilled.o: $(hdrdir)/ruby/internal/newobj.h
+chilled.o: $(hdrdir)/ruby/internal/scan_args.h
+chilled.o: $(hdrdir)/ruby/internal/special_consts.h
+chilled.o: $(hdrdir)/ruby/internal/static_assert.h
+chilled.o: $(hdrdir)/ruby/internal/stdalign.h
+chilled.o: $(hdrdir)/ruby/internal/stdbool.h
+chilled.o: $(hdrdir)/ruby/internal/symbol.h
+chilled.o: $(hdrdir)/ruby/internal/value.h
+chilled.o: $(hdrdir)/ruby/internal/value_type.h
+chilled.o: $(hdrdir)/ruby/internal/variable.h
+chilled.o: $(hdrdir)/ruby/internal/warning_push.h
+chilled.o: $(hdrdir)/ruby/internal/xmalloc.h
+chilled.o: $(hdrdir)/ruby/missing.h
+chilled.o: $(hdrdir)/ruby/ruby.h
+chilled.o: $(hdrdir)/ruby/st.h
+chilled.o: $(hdrdir)/ruby/subst.h
+chilled.o: chilled.c
 coderange.o: $(RUBY_EXTCONF_H)
 coderange.o: $(arch_hdrdir)/ruby/config.h
 coderange.o: $(hdrdir)/ruby/assert.h

include/ruby/internal/intern/string.h

@@ -601,6 +601,21 @@ VALUE rb_str_dup(VALUE str);
  */
 VALUE rb_str_resurrect(VALUE str);
 
+/**
+ * Returns whether a string is chilled or not.
+ *
+ * This function is temporary and users must check for its presence using
+ * #ifdef HAVE_RB_STR_CHILLED_P. If HAVE_RB_STR_CHILLED_P is not defined, then
+ * strings can't be chilled.
+ *
+ * @param[in]  str  A string.
+ * @retval     1    The string is chilled.
+ * @retval     0    Otherwise.
+ */
+bool rb_str_chilled_p(VALUE str);
+
+#define HAVE_RB_STR_CHILLED_P 1
+
 /**
  * Obtains a "temporary  lock" of the string.  This  advisory locking mechanism
  * prevents other  cooperating threads from  tampering the receiver.   The same

string.c

@@ -1833,6 +1833,12 @@ rb_ec_str_resurrect(struct rb_execution_context_struct *ec, VALUE str, bool chil
     return new_str;
 }
 
+bool
+rb_str_chilled_p(VALUE str)
+{
+    return CHILLED_STRING_P(str);
+}
+
 /*
  *
  *  call-seq:

test/-ext-/string/test_chilled.rb

@@ -0,0 +1,19 @@
+require 'test/unit'
+require '-test-/string'
+
+class Test_String_ChilledString < Test::Unit::TestCase
+  def test_rb_str_chilled_p
+    str = ""
+    assert_equal true, Bug::String.rb_str_chilled_p(str)
+  end
+
+  def test_rb_str_chilled_p_frozen
+    str = "".freeze
+    assert_equal false, Bug::String.rb_str_chilled_p(str)
+  end
+
+  def test_rb_str_chilled_p_mutable
+    str = "".dup
+    assert_equal false, Bug::String.rb_str_chilled_p(str)
+  end
+end