[Mono-bugs] [Bug 77098][Blo] New - FileStream's position gets
changed by implicit and explicit flushing
bugzilla-daemon at bugzilla.ximian.com
bugzilla-daemon at bugzilla.ximian.com
Tue Dec 27 05:26:44 EST 2005
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Changed by c.schwarz at systemtechnik-online.de.
http://bugzilla.ximian.com/show_bug.cgi?id=77098
--- shadow/77098 2005-12-27 05:26:44.000000000 -0500
+++ shadow/77098.tmp.5501 2005-12-27 05:26:44.000000000 -0500
@@ -0,0 +1,96 @@
+Bug#: 77098
+Product: Mono: Class Libraries
+Version: 1.0
+OS:
+OS Details: Windows XP SP2
+Status: NEW
+Resolution:
+Severity:
+Priority: Blocker
+Component: CORLIB
+AssignedTo: mono-bugs at ximian.com
+ReportedBy: c.schwarz at systemtechnik-online.de
+QAContact: mono-bugs at ximian.com
+TargetMilestone: ---
+URL:
+Cc:
+Summary: FileStream's position gets changed by implicit and explicit flushing
+
+Description of Problem:
+I'm not sure if that is really a bug, but at least the MS .NET Framework's
+FileStream behaves exactly the way would I expect. That means flushing of
+FileStream, either explicit (i.e. by calling Flush() method) or implicit
+(i.e. by calling get_Length) doesn't change the file pointer.
+
+Steps to reproduce the problem:
+1. Creating a FileStream (new file) with buffering
+2. Write data to the FileStream which is smaller than the buffer
+3. Set position of the FileStream to 0
+4. Do something which explicitely or implicitely causes flushing of the
+buffer (like query file size (get_Length) or calling Flush() method)
+
+Actual Results:
+FileStream's position is at the end of the file
+
+Expected Results:
+FileStream's position should be 0
+
+How often does this happen?
+Always
+
+Additional Information:
+Here are 2 tests that demonstrates the problem.
+
+[Test]
+public void TestPositionAfterImplicitFlushProblem()
+{
+ using (FileStreamEx fs = new FileStreamEx(Path.Combine(TempFolder,
+"TestSetPositionImplicitFlushProblem.dat"),
+ FileMode.Create,
+ FileAccess.ReadWrite,
+ FileShare.None,
+ 8192))
+ {
+ byte[] buffer1 = new byte[100];
+ byte[] buffer2 = new byte[buffer1.Length];
+
+ for (int index = 0; (index < buffer1.Length); index++)
+ buffer1[index] = (byte)(index & 0xff);
+
+ fs.Write(buffer1, 0, buffer1.Length);
+ fs.Position = 0;
+
+ Assert.AreEqual(fs.Length, 100); // Implicit flushing
+
+ Assert.AreEqual(fs.Position, 0);
+ Assert.AreEqual(fs.Read(buffer2, 0, buffer2.Length), buffer2.Length);
+ Assert.AreEqual(buffer1, buffer2);
+ }
+}
+
+[Test]
+public void TestPositionAfterExplicitFlushProblem()
+{
+ using (FileStreamEx fs = new FileStreamEx(Path.Combine(TempFolder,
+"TestPositionAfterExplicitFlushProblem.dat"),
+ FileMode.Create,
+ FileAccess.ReadWrite,
+ FileShare.None,
+ 8192))
+ {
+ byte[] buffer1 = new byte[100];
+ byte[] buffer2 = new byte[buffer1.Length];
+
+ for (int index = 0; (index < buffer1.Length); index++)
+ buffer1[index] = (byte)(index & 0xff);
+
+ fs.Write(buffer1, 0, buffer1.Length);
+ fs.Position = 0;
+
+ fs.Flush(); // Explicit flushing
+
+ Assert.AreEqual(fs.Position, 0);
+ Assert.AreEqual(fs.Read(buffer2, 0, buffer2.Length), buffer2.Length);
+ Assert.AreEqual(buffer1, buffer2);
+ }
+}
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