From: João Matos <joao@tritao.eu>
Date: Tue, 7 Apr 2015 16:31:12 +0000 (+0100)
Subject: Merge pull request #1684 from Garciat/fix-zlib-helper
X-Git-Url: http://wien.tomnetworks.com/gitweb/?a=commitdiff_plain;h=bcb651443de098171a4e71a71d7f21a599323a4f;hp=6c38ce4ea40d0bcacf9dfbd72d987d2760145982;p=mono.git

Merge pull request #1684 from Garciat/fix-zlib-helper

[System] Fix DeflateStream throw on empty flush, double flush. Fixes #28777
---

diff --git a/mcs/class/System/Test/System.IO.Compression/DeflateStreamTest.cs b/mcs/class/System/Test/System.IO.Compression/DeflateStreamTest.cs
index 3a0c7d89e58..f3cefe8c151 100644
--- a/mcs/class/System/Test/System.IO.Compression/DeflateStreamTest.cs
+++ b/mcs/class/System/Test/System.IO.Compression/DeflateStreamTest.cs
@@ -374,6 +374,29 @@ namespace MonoTests.System.IO.Compression
 			compressing.Close ();
 			backing.Close ();
 		}
+
+		[Test]
+		public void Bug28777_EmptyFlush ()
+		{
+			MemoryStream backing = new MemoryStream ();
+			DeflateStream compressing = new DeflateStream (backing, CompressionLevel.Fastest, true);
+			compressing.Flush ();
+			compressing.Close ();
+			backing.Close ();
+		}
+		
+		[Test]
+		public void Bug28777_DoubleFlush ()
+		{
+			byte[] buffer = new byte [4096];
+			MemoryStream backing = new MemoryStream ();
+			DeflateStream compressing = new DeflateStream (backing, CompressionLevel.Fastest, true);
+			compressing.Write (buffer, 0, buffer.Length);
+			compressing.Flush ();
+			compressing.Flush ();
+			compressing.Close ();
+			backing.Close ();
+		}
 	}
 }
 
diff --git a/support/zlib-helper.c b/support/zlib-helper.c
index 83455413b36..38696260a09 100644
--- a/support/zlib-helper.c
+++ b/support/zlib-helper.c
@@ -90,6 +90,8 @@ CreateZStream (gint compress, guchar gzip, read_write_func func, void *gchandle)
 	result->gchandle = gchandle;
 	result->compress = compress;
 	result->buffer = g_new (guchar, BUFFER_SIZE);
+	result->stream->next_out = result->buffer;
+	result->stream->avail_out = BUFFER_SIZE;
 	return result;
 }
 
@@ -148,7 +150,7 @@ flush_internal (ZStream *stream, gboolean is_final)
 	if (!stream->compress)
 		return 0;
 
-	if (!is_final) {
+	if (!is_final && stream->stream->avail_in != 0) {
 		status = deflate (stream->stream, Z_PARTIAL_FLUSH);
 		if (status != Z_OK && status != Z_STREAM_END)
 			return status;