file.c: shrink expanded path

* file.c (expand_path): shrink expanded path which no longer needs
  rooms to append.  [ruby-core:63114] [Bug #9934]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46410 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Thu Jun 12 13:09:03 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* file.c (expand_path): shrink expanded path which no longer needs
+	  rooms to append.  [ruby-core:63114] [Bug #9934]
+
 Wed Jun 11 17:37:48 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* configure.in (rb_cv_scalar_pthread_t): pthread_t is not required

file.c

@@ -3507,6 +3507,16 @@ rb_file_expand_path_internal(VALUE fname, VALUE dname, int abs_mode, int long_na
 
 #define EXPAND_PATH_BUFFER() rb_usascii_str_new(0, MAXPATHLEN + 2)
 
+static VALUE
+str_shrink(VALUE str)
+{
+    rb_str_resize(str, RSTRING_LEN(str));
+    return str;
+}
+
+#define expand_path(fname, dname, abs_mode, long_name, result) \
+    str_shrink(rb_file_expand_path_internal(fname, dname, abs_mode, long_name, result))
+
 #define check_expand_path_args(fname, dname) \
     (((fname) = rb_get_path(fname)), \
      (void)(NIL_P(dname) ? (dname) : ((dname) = rb_get_path(dname))))
@@ -3521,13 +3531,13 @@ VALUE
 rb_file_expand_path(VALUE fname, VALUE dname)
 {
     check_expand_path_args(fname, dname);
-    return rb_file_expand_path_internal(fname, dname, 0, 1, EXPAND_PATH_BUFFER());
+    return expand_path(fname, dname, 0, 1, EXPAND_PATH_BUFFER());
 }
 
 VALUE
 rb_file_expand_path_fast(VALUE fname, VALUE dname)
 {
-    return rb_file_expand_path_internal(fname, dname, 0, 0, EXPAND_PATH_BUFFER());
+    return expand_path(fname, dname, 0, 0, EXPAND_PATH_BUFFER());
 }
 
 /*
@@ -3575,7 +3585,7 @@ VALUE
 rb_file_absolute_path(VALUE fname, VALUE dname)
 {
     check_expand_path_args(fname, dname);
-    return rb_file_expand_path_internal(fname, dname, 1, 1, EXPAND_PATH_BUFFER());
+    return expand_path(fname, dname, 1, 1, EXPAND_PATH_BUFFER());
 }
 
 /*
@@ -5519,6 +5529,7 @@ is_explicit_relative(const char *path)
 static VALUE
 copy_path_class(VALUE path, VALUE orig)
 {
+    str_shrink(path);
     RBASIC_SET_CLASS(path, rb_obj_class(orig));
     OBJ_FREEZE(path);
     return path;

test/ruby/test_file_exhaustive.rb

@@ -458,6 +458,13 @@ class TestFileExhaustive < Test::Unit::TestCase
     end
   end
 
+  def test_expand_path_memsize
+    bug9934 = '[ruby-core:63114] [Bug #9934]'
+    require "objspace"
+    path = File.expand_path("/foo")
+    assert_operator(ObjectSpace.memsize_of(path), :<=, path.bytesize, bug9934)
+  end
+
   def test_expand_path_encoding
     drive = (DRIVE ? 'C:' : '')
     if Encoding.find("filesystem") == Encoding::CP1251