From ba5aa6066869e80af71fddb0b42d31222f328c97 Mon Sep 17 00:00:00 2001 From: normal Date: Tue, 31 Jan 2017 00:41:56 +0000 Subject: sprintf.c: avoid garbage in common (no exception) case Format strings which are dynamically-generated will benefit from this. This won't cover exceptions, but exceptions for sprintf should be too uncommon to care about (unlike IO) * sprintf.c (rb_str_format): use rb_str_tmp_frozen_{acquire,release} * test/ruby/test_sprintf.rb (test_no_hidden_garbage): new test git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57473 b2dd03c8-39d4-4d8f-98ff-823fe69b080e --- sprintf.c | 6 ++++-- test/ruby/test_sprintf.rb | 10 ++++++++++ 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/sprintf.c b/sprintf.c index 4342904bdc..40872c0c16 100644 --- a/sprintf.c +++ b/sprintf.c @@ -475,6 +475,7 @@ rb_str_format(int argc, const VALUE *argv, VALUE fmt) int tainted = 0; VALUE nextvalue; VALUE tmp; + VALUE orig; VALUE str; volatile VALUE hash = Qundef; @@ -498,7 +499,8 @@ rb_str_format(int argc, const VALUE *argv, VALUE fmt) if (OBJ_TAINTED(fmt)) tainted = 1; StringValue(fmt); enc = rb_enc_get(fmt); - fmt = rb_str_new4(fmt); + orig = fmt; + fmt = rb_str_tmp_frozen_acquire(fmt); p = RSTRING_PTR(fmt); end = p + RSTRING_LEN(fmt); blen = 0; @@ -1196,7 +1198,7 @@ rb_str_format(int argc, const VALUE *argv, VALUE fmt) } sprint_exit: - RB_GC_GUARD(fmt); + rb_str_tmp_frozen_release(orig, fmt); /* XXX - We cannot validate the number of arguments if (digit)$ style used. */ if (posarg >= 0 && nextarg < argc) { diff --git a/test/ruby/test_sprintf.rb b/test/ruby/test_sprintf.rb index 595bf6d782..c80f88b15e 100644 --- a/test/ruby/test_sprintf.rb +++ b/test/ruby/test_sprintf.rb @@ -451,4 +451,14 @@ class TestSprintf < Test::Unit::TestCase bug = 'https://github.com/mruby/mruby/issues/3347' assert_equal("!", sprintf("%*c", 0, ?!.ord), bug) end + + def test_no_hidden_garbage + fmt = [4, 2, 2].map { |x| "%0#{x}d" }.join('-') # defeats optimization + ObjectSpace.count_objects(res = {}) # creates strings on first call + before = ObjectSpace.count_objects(res)[:T_STRING] + val = sprintf(fmt, 1970, 1, 1) + after = ObjectSpace.count_objects(res)[:T_STRING] + assert_equal before + 1, after, 'only new string is the created one' + assert_equal '1970-01-01', val + end end -- cgit v1.2.3