From: Juraj Skripsky <js@hotfeet.ch>
Date: Sun, 1 Jun 2008 17:57:48 +0000 (-0000)
Subject: 2008-06-01  Juraj Skripsky  <js@hotfeet.ch>
X-Git-Url: http://wien.tomnetworks.com/gitweb/?a=commitdiff_plain;h=169c1ff0f6e24d97a757d67ac8971a386116c846;p=mono.git

2008-06-01  Juraj Skripsky  <js@hotfeet.ch>

	* StringBuilder.cs (ToString): Use String.SubstringUnchecked instead
	of String.Substring, as the former is guaranteed to create a new
	string object. Fixes bug #395904.

	* String.cs (Substring): Blocking bug #395904 has been fixed,
	re-enable optimization.

	* StringTest.cs (Substring2): Blocking bug #395904 has been fixed,
	re-enable test.


svn path=/trunk/mcs/; revision=104629
---

diff --git a/mcs/class/corlib/System.Text/ChangeLog b/mcs/class/corlib/System.Text/ChangeLog
index 6b2a683ca23..ea22ad83217 100644
--- a/mcs/class/corlib/System.Text/ChangeLog
+++ b/mcs/class/corlib/System.Text/ChangeLog
@@ -1,3 +1,9 @@
+2008-06-01  Juraj Skripsky  <js@hotfeet.ch>
+
+	* StringBuilder.cs (ToString): Use String.SubstringUnchecked instead
+	of String.Substring, as the former is guaranteed to create a new
+	string object. Fixes bug #395904.
+
 2008-05-15  Andreas Nahr <ClassDevelopment@A-SoftTech.com>
 
 	* StringBuilder.cs: Resubmit uncritical parts of String cleanup patch
diff --git a/mcs/class/corlib/System.Text/StringBuilder.cs b/mcs/class/corlib/System.Text/StringBuilder.cs
index f9ff5c34259..a3c37831dae 100644
--- a/mcs/class/corlib/System.Text/StringBuilder.cs
+++ b/mcs/class/corlib/System.Text/StringBuilder.cs
@@ -203,7 +203,9 @@ namespace System.Text {
 			// If we only have a half-full buffer we return a new string.
 			if (_length < (_str.Length >> 1)) 
 			{
-				_cached_str = _str.Substring(0, _length);
+				// use String.SubstringUnchecked instead of String.Substring
+				// as the former is guaranteed to create a new string object
+				_cached_str = _str.SubstringUnchecked (0, _length);
 				return _cached_str;
 			}
 
@@ -219,7 +221,12 @@ namespace System.Text {
 			if (startIndex < 0 || length < 0 || startIndex > _length - length)
 				throw new ArgumentOutOfRangeException();
 
-			return _str.Substring (startIndex, length);
+			// use String.SubstringUnchecked instead of String.Substring
+			// as the former is guaranteed to create a new string object
+			if (startIndex == 0 && length == _length)
+				return ToString ();
+			else
+				return _str.SubstringUnchecked (startIndex, length);
 		}
 
 		public int EnsureCapacity (int capacity) 
diff --git a/mcs/class/corlib/System/ChangeLog b/mcs/class/corlib/System/ChangeLog
index 8f2edd62c12..bd2ea28cec3 100644
--- a/mcs/class/corlib/System/ChangeLog
+++ b/mcs/class/corlib/System/ChangeLog
@@ -1,3 +1,8 @@
+2008-06-01  Juraj Skripsky  <js@hotfeet.ch>
+
+	* String.cs (Substring): Blocking bug #395904 has been fixed,
+	re-enable optimization.
+
 2008-06-01  Andreas Nahr <ClassDevelopment@A-SoftTech.com>
 
 	* String.cs: Replace Split IndexOf
diff --git a/mcs/class/corlib/System/String.cs b/mcs/class/corlib/System/String.cs
index 4f86afcffc9..87e92947462 100644
--- a/mcs/class/corlib/System/String.cs
+++ b/mcs/class/corlib/System/String.cs
@@ -362,16 +362,15 @@ namespace System
 			if (startIndex > this.length - length)
 				throw new ArgumentOutOfRangeException ("length", "startIndex + length > this.length");
 #if NET_2_0
-			// FIXME: this causes regressions in System.Xml
-			/*
 			if (startIndex == 0 && length == this.length)
 				return this;
-			*/
 #endif
 
 			return SubstringUnchecked (startIndex, length);
 		}
 
+		// This method is used by StringBuilder.ToString() and is expected to
+		// always create a new string object (or return String.Empty). 
 		internal unsafe String SubstringUnchecked (int startIndex, int length)
 		{
 			if (length == 0)
diff --git a/mcs/class/corlib/Test/System/ChangeLog b/mcs/class/corlib/Test/System/ChangeLog
index 555c5cff10d..d08106c40ca 100644
--- a/mcs/class/corlib/Test/System/ChangeLog
+++ b/mcs/class/corlib/Test/System/ChangeLog
@@ -1,3 +1,8 @@
+2008-06-01  Juraj Skripsky  <js@hotfeet.ch>
+
+	* StringTest.cs (Substring2): Blocking bug #395904 has been fixed,
+	re-enable test. 
+
 2008-05-24  Andreas Nahr <ClassDevelopment@A-SoftTech.com>
 
 	* StringTest.cs: Comment out a test that currently fails by checking for
diff --git a/mcs/class/corlib/Test/System/StringTest.cs b/mcs/class/corlib/Test/System/StringTest.cs
index 8bbef31d334..1b0c4a4445c 100644
--- a/mcs/class/corlib/Test/System/StringTest.cs
+++ b/mcs/class/corlib/Test/System/StringTest.cs
@@ -3454,8 +3454,7 @@ public class StringTest : TestCase
 		AssertEquals ("#3", "origina", s.Substring (0, s.Length - 1));
 		AssertEquals ("#4", s, s.Substring (0, s.Length));
 #if NET_2_0
-		// FIXME: enabling the fix for this causes regressions in System.Xml
-		//AssertSame ("#5", s, s.Substring (0, s.Length));
+		AssertSame ("#5", s, s.Substring (0, s.Length));
 #else
 		Assert ("#5", !object.ReferenceEquals (s, s.Substring (0, s.Length)));
 #endif