For JRUBY-5778: net http and gzip decompression in 1.9

* Add GzipWriter and GzipReader#initialize that accepts options hash (ignored for now).
* Full impl in 1.6.5?

src/org/jruby/RubyZlib.java

@@ -46,6 +46,7 @@
 import java.util.zip.DeflaterOutputStream;
 import java.util.zip.Inflater;
 import java.util.zip.InflaterInputStream;
+import org.jcodings.Encoding;
 
 import org.joda.time.DateTime;
 
@@ -71,6 +72,8 @@
 import org.jruby.util.IOOutputStream;
 import org.jruby.util.io.Stream;
 
+import static org.jruby.CompatVersion.*;
+
 @JRubyModule(name="Zlib")
 public class RubyZlib {
     // version
@@ -1429,23 +1432,34 @@ private long bytesToUInt(byte[] bytes, int pos) {
         }
 
         @JRubyMethod(visibility = PRIVATE)
-        public IRubyObject initialize(IRubyObject arg, Block unusedBlock) {
-            realIo = arg;
+        public IRubyObject initialize(IRubyObject stream) {
+            realIo = stream;
             line = 0;
             position = 0;
             io = new HeaderReadableGZIPInputStream(new CountingIOInputStream(realIo));
             bufferedStream = new BufferedInputStream(io);
             return this;
         }
 
+        @JRubyMethod(visibility = PRIVATE, compat = RUBY1_9)
+        public IRubyObject initialize19(IRubyObject stream) {
+            return initialize(stream);
+        }
+
+        @JRubyMethod(visibility = PRIVATE, compat = RUBY1_9)
+        public IRubyObject initialize19(IRubyObject stream, IRubyObject options) {
+            initialize(stream);
+            return this;
+        }
+
         @JRubyMethod
         public IRubyObject rewind() {
             Ruby rt = getRuntime();
             // should invoke seek on realIo...
             realIo.callMethod(rt.getCurrentContext(), "seek",
                     new IRubyObject[]{rt.newFixnum(-io.pos()), rt.newFixnum(Stream.SEEK_CUR)});
             // ... and then reinitialize
-            initialize(realIo, Block.NULL_BLOCK);
+            initialize(realIo);
             return getRuntime().getNil();
         }
 
@@ -1878,8 +1892,13 @@ private void writeTrailer() throws IOException {
         private HeaderModifyableGZIPOutputStream io;
 
         @JRubyMethod(required = 1, rest = true, visibility = PRIVATE)
-        public IRubyObject initialize(IRubyObject[] args, Block unusedBlock) {
-            realIo = (RubyObject) args[0];
+        public IRubyObject initialize(IRubyObject[] args) {
+            return initialize(args[0]);
+        }
+
+        @JRubyMethod(visibility = PRIVATE)
+        public IRubyObject initialize(IRubyObject arg) {
+            realIo = (RubyObject) arg;
             try {
                 io = new HeaderModifyableGZIPOutputStream(realIo);
                 return this;
@@ -1888,6 +1907,17 @@ public IRubyObject initialize(IRubyObject[] args, Block unusedBlock) {
             }
         }
 
+        @JRubyMethod(visibility = PRIVATE, compat = RUBY1_9)
+        public IRubyObject initialize19(IRubyObject stream) {
+            return initialize(stream);
+        }
+
+        @JRubyMethod(visibility = PRIVATE, compat = RUBY1_9)
+        public IRubyObject initialize19(IRubyObject stream, IRubyObject options) {
+            initialize(stream);
+            return this;
+        }
+
         @Override
         @JRubyMethod(name = "close")
         public IRubyObject close() {