merge revision(s) r46408,r46410,r46413,r46414,r46424,r46436,r46437: [Backport #9934]

	string.c: shrink too big buffer

	* string.c (rb_str_resize): shrink the buffer even if new length
  is same but it is enough smaller than the capacity.
	* file.c (expand_path): shrink expanded path which no longer needs
	  rooms to append.  [ruby-core:63114] [Bug #9934]

	* string.c (rb_str_resize): should consider the capacity instead
	  of the old length, as pointed out by nagachika.

	* string.c (rb_str_resize): update capa only when buffer get
	  reallocated.
	  http://d.hatena.ne.jp/nagachika/20140613/ruby_trunk_changes_46413_46420#r46413


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@47215 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 7 insertions, 4 deletions

diff --git a/string.c b/string.c
index 006a8b4639..36f6888778 100644
--- a/string.c
+++ b/string.c
@@ -2034,9 +2034,11 @@ rb_str_resize(VALUE str, long len)
     independent = str_independent(str);
     ENC_CODERANGE_CLEAR(str);
     slen = RSTRING_LEN(str);
-    if (len != slen) {
+    {
+	long capa;
 	const int termlen = TERM_LEN(str);
 	if (STR_EMBED_P(str)) {
+	    if (len == slen) return str;
 	    if (len + termlen <= RSTRING_EMBED_LEN_MAX + 1) {
 		STR_SET_EMBED_LEN(str, len);
 		TERM_FILL(RSTRING(str)->as.ary + len, termlen);
@@ -2056,14 +2058,15 @@ rb_str_resize(VALUE str, long len)
 	    return str;
 	}
 	else if (!independent) {
+	    if (len == slen) return str;
 	    str_make_independent_expand(str, len - slen);
 	}
-	else if (slen < len || slen - len > 1024) {
+	else if ((capa = RSTRING(str)->as.heap.aux.capa) < len ||
+		 (capa - len) > (len < 1024 ? len : 1024)) {
 	    REALLOC_N(RSTRING(str)->as.heap.ptr, char, len + termlen);
-	}
-	if (!STR_NOCAPA_P(str)) {
 	    RSTRING(str)->as.heap.aux.capa = len;
 	}
+	else if (len == slen) return str;
 	RSTRING(str)->as.heap.len = len;
 	TERM_FILL(RSTRING(str)->as.heap.ptr + len, termlen); /* sentinel */
     }