From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: X-Spam-Status: No, score=-2.9 required=3.0 tests=ALL_TRUSTED,AWL,BAYES_00 shortcircuit=no autolearn=unavailable version=3.3.2 X-Original-To: spew@80x24.org Received: from localhost (dcvr.yhbt.net [127.0.0.1]) by dcvr.yhbt.net (Postfix) with ESMTP id 3F37B633803 for ; Sat, 4 Jul 2015 05:25:34 +0000 (UTC) From: Eric Wong To: spew@80x24.org Subject: [PATCH] string.c: ensure String#freeze resizes internal buffer Date: Sat, 4 Jul 2015 05:25:34 +0000 Message-Id: <1435987534-9787-1-git-send-email-e@80x24.org> List-Id: rb_str_freeze may resize oversized buffers to save memory, so favor it over rb_obj_freeze. This is useful because IO methods do not prematurely shrink buffers, as they are likely to be overwritten with full data. * string.c (Init_String): use rb_str_freeze for String#freeze --- string.c | 2 +- test/ruby/test_optimization.rb | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/string.c b/string.c index 34c77a5..15d4220 100644 --- a/string.c +++ b/string.c @@ -9143,7 +9143,7 @@ Init_String(void) rb_define_method(rb_cString, "byteslice", rb_str_byteslice, -1); rb_define_method(rb_cString, "scrub", str_scrub, -1); rb_define_method(rb_cString, "scrub!", str_scrub_bang, -1); - rb_define_method(rb_cString, "freeze", rb_obj_freeze, 0); + rb_define_method(rb_cString, "freeze", rb_str_freeze, 0); rb_define_method(rb_cString, "to_i", rb_str_to_i, -1); rb_define_method(rb_cString, "to_f", rb_str_to_f, 0); diff --git a/test/ruby/test_optimization.rb b/test/ruby/test_optimization.rb index 4a5484e..e2efc9d 100644 --- a/test/ruby/test_optimization.rb +++ b/test/ruby/test_optimization.rb @@ -1,4 +1,5 @@ require 'test/unit' +require 'objspace' class TestRubyOptimization < Test::Unit::TestCase @@ -122,6 +123,24 @@ class TestRubyOptimization < Test::Unit::TestCase assert_redefine_method('String', 'freeze', 'assert_nil "foo".freeze') end + def test_string_freeze_saves_memory + n = 16384 + data = '.'.freeze + r, w = IO.pipe + w.write data + + s = r.readpartial(n, '') + assert_operator ObjectSpace.memsize_of(s), :>=, n, + 'IO buffer NOT resized prematurely because will likely be reused' + + s.freeze + assert_equal ObjectSpace.memsize_of(data), ObjectSpace.memsize_of(s), + 'buffer resized on freeze since it cannot be written to again' + ensure + r.close if r + w.close if w + end + def test_string_eq_neq %w(== !=).each do |m| assert_redefine_method('String', m, <<-end) -- EW