Make #211 work with Java 5

* Use java.util.zip.Deflater only when running under Java 7

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyFrameDecoder.java

@@ -34,7 +34,8 @@ public class SpdyFrameDecoder extends FrameDecoder {
     private final int maxFrameSize;
     private final int maxHeaderSize;
 
-    private final SpdyZlibDecoder headerBlockDecompressor = new SpdyZlibDecoder();
+    private final SpdyHeaderBlockDecompressor headerBlockDecompressor =
+            SpdyHeaderBlockDecompressor.newInstance();
 
     /**
      * Creates a new instance with the default {@code maxChunkSize (8192)},

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyFrameEncoder.java

@@ -34,7 +34,7 @@ import io.netty.handler.codec.oneone.OneToOneEncoder;
 public class SpdyFrameEncoder extends OneToOneEncoder {
 
     private volatile boolean finished;
-    private final SpdyZlibEncoder headerBlockCompressor;
+    private final SpdyHeaderBlockCompressor headerBlockCompressor;
 
     /**
      * Creates a new instance with the default {@code compressionLevel (6)},
@@ -49,7 +49,7 @@ public class SpdyFrameEncoder extends OneToOneEncoder {
      */
     public SpdyFrameEncoder(int compressionLevel, int windowBits, int memLevel) {
         super();
-        headerBlockCompressor = new SpdyZlibEncoder(compressionLevel);
+        headerBlockCompressor = SpdyHeaderBlockCompressor.newInstance(compressionLevel, windowBits, memLevel);
     }
 
     @Override

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyHeaderBlockCompressor.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2012 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.spdy;
+
+import java.util.zip.Deflater;
+
+import io.netty.buffer.ChannelBuffer;
+
+abstract class SpdyHeaderBlockCompressor {
+
+    private static final boolean USE_ZLIB;
+
+    static {
+        boolean java7 = false;
+        try {
+            Deflater.class.getDeclaredMethod(
+                    "deflate",
+                    new Class<?>[] { byte[].class, int.class, int.class, int.class });
+            java7 = true;
+        } catch (Exception e) {
+            // Ignore
+        }
+
+        USE_ZLIB = java7;
+    }
+
+    static SpdyHeaderBlockCompressor newInstance(int compressionLevel, int windowBits, int memLevel) {
+        if (USE_ZLIB) {
+            return new SpdyZlibEncoder(compressionLevel);
+        } else {
+            return new SpdyJZlibEncoder(compressionLevel, windowBits, memLevel);
+        }
+    }
+
+    abstract void setInput(ChannelBuffer decompressed);
+    abstract void encode(ChannelBuffer compressed);
+    abstract void end();
+}

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyHeaderBlockDecompressor.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2012 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.handler.codec.spdy;
+
+import io.netty.buffer.ChannelBuffer;
+
+abstract class SpdyHeaderBlockDecompressor {
+
+    static SpdyHeaderBlockDecompressor newInstance() {
+        return new SpdyJZlibDecoder();
+    }
+
+    abstract void setInput(ChannelBuffer compressed);
+    abstract void decode(ChannelBuffer decompressed);
+}

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyJZlibDecoder.java

@@ -28,21 +28,21 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.jboss.netty.handler.codec.spdy;
+package io.netty.handler.codec.spdy;
 
-import org.jboss.netty.buffer.ChannelBuffer;
+import io.netty.buffer.ChannelBuffer;
-import org.jboss.netty.handler.codec.compression.CompressionException;
+import io.netty.handler.codec.compression.CompressionException;
-import org.jboss.netty.util.internal.jzlib.JZlib;
+import io.netty.util.internal.jzlib.JZlib;
-import org.jboss.netty.util.internal.jzlib.ZStream;
+import io.netty.util.internal.jzlib.ZStream;
 
-import static org.jboss.netty.handler.codec.spdy.SpdyCodecUtil.*;
+import static io.netty.handler.codec.spdy.SpdyCodecUtil.*;
 
-class SpdyZlibDecoder {
+class SpdyJZlibDecoder extends SpdyHeaderBlockDecompressor {
 
     private final byte[] out = new byte[8192];
     private final ZStream z = new ZStream();
 
-    public SpdyZlibDecoder() {
+    public SpdyJZlibDecoder() {
         int resultCode;
         resultCode = z.inflateInit(JZlib.W_ZLIB);
         if (resultCode != JZlib.Z_OK) {
@@ -51,6 +51,7 @@ class SpdyZlibDecoder {
         z.next_out = out;
     }
 
+    @Override
     public void setInput(ChannelBuffer compressed) {
         byte[] in = new byte[compressed.readableBytes()];
         compressed.readBytes(in);
@@ -59,6 +60,7 @@ class SpdyZlibDecoder {
         z.avail_in = in.length;
     }
 
+    @Override
     public void decode(ChannelBuffer decompressed) {
         z.next_out_index = 0;
         z.avail_out = out.length;

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyJZlibEncoder.java

@@ -0,0 +1,113 @@
+/*
+ * Copyright 2012 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+/*
+ * Copyright 2012 Twitter, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License. You may obtain
+ * a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.netty.handler.codec.spdy;
+
+import static io.netty.handler.codec.spdy.SpdyCodecUtil.*;
+
+import io.netty.buffer.ChannelBuffer;
+import io.netty.handler.codec.compression.CompressionException;
+import io.netty.util.internal.jzlib.JZlib;
+import io.netty.util.internal.jzlib.ZStream;
+
+class SpdyJZlibEncoder extends SpdyHeaderBlockCompressor {
+
+    private final ZStream z = new ZStream();
+
+    public SpdyJZlibEncoder(int compressionLevel, int windowBits, int memLevel) {
+        if (compressionLevel < 0 || compressionLevel > 9) {
+            throw new IllegalArgumentException(
+                    "compressionLevel: " + compressionLevel + " (expected: 0-9)");
+        }
+        if (windowBits < 9 || windowBits > 15) {
+            throw new IllegalArgumentException(
+                    "windowBits: " + windowBits + " (expected: 9-15)");
+        }
+        if (memLevel < 1 || memLevel > 9) {
+            throw new IllegalArgumentException(
+                    "memLevel: " + memLevel + " (expected: 1-9)");
+        }
+
+        int resultCode = z.deflateInit(
+                compressionLevel, windowBits, memLevel, JZlib.W_ZLIB);
+        if (resultCode != JZlib.Z_OK) {
+            throw new CompressionException(
+                    "failed to initialize an SPDY header block deflater: " + resultCode);
+        } else {
+            resultCode = z.deflateSetDictionary(SPDY_DICT, SPDY_DICT.length);
+            if (resultCode != JZlib.Z_OK) {
+                throw new CompressionException(
+                        "failed to set the SPDY dictionary: " + resultCode);
+            }
+        }
+    }
+
+    @Override
+    public void setInput(ChannelBuffer decompressed) {
+        byte[] in = new byte[decompressed.readableBytes()];
+        decompressed.readBytes(in);
+        z.next_in = in;
+        z.next_in_index = 0;
+        z.avail_in = in.length;
+    }
+
+    @Override
+    public void encode(ChannelBuffer compressed) {
+        try {
+            byte[] out = new byte[(int) Math.ceil(z.next_in.length * 1.001) + 12];
+            z.next_out = out;
+            z.next_out_index = 0;
+            z.avail_out = out.length;
+
+            int resultCode = z.deflate(JZlib.Z_SYNC_FLUSH);
+            if (resultCode != JZlib.Z_OK) {
+                throw new CompressionException("compression failure: " + resultCode);
+            }
+
+            if (z.next_out_index != 0) {
+                compressed.writeBytes(out, 0, z.next_out_index);
+            }
+        } finally {
+            // Deference the external references explicitly to tell the VM that
+            // the allocated byte arrays are temporary so that the call stack
+            // can be utilized.
+            // I'm not sure if the modern VMs do this optimization though.
+            z.next_in = null;
+            z.next_out = null;
+        }
+    }
+
+    @Override
+    public void end() {
+        z.deflateEnd();
+        z.next_in = null;
+        z.next_out = null;
+    }
+}

codec-http/src/main/java/io/netty/handler/codec/spdy/SpdyZlibEncoder.java

@@ -30,13 +30,13 @@
  */
 package io.netty.handler.codec.spdy;
 
-import static io.netty.handler.codec.spdy.SpdyCodecUtil.*;
-
 import java.util.zip.Deflater;
 
 import io.netty.buffer.ChannelBuffer;
 
-class SpdyZlibEncoder {
+import static io.netty.handler.codec.spdy.SpdyCodecUtil.*;
+
+class SpdyZlibEncoder extends SpdyHeaderBlockCompressor {
 
     private final byte[] out = new byte[8192];
     private final Deflater compressor;
@@ -50,12 +50,14 @@ class SpdyZlibEncoder {
         compressor.setDictionary(SPDY_DICT);
     }
 
+    @Override
     public void setInput(ChannelBuffer decompressed) {
         byte[] in = new byte[decompressed.readableBytes()];
         decompressed.readBytes(in);
         compressor.setInput(in);
     }
 
+    @Override
     public void encode(ChannelBuffer compressed) {
         while (!compressor.needsInput()) {
             int numBytes = compressor.deflate(out, 0, out.length, Deflater.SYNC_FLUSH);
@@ -63,6 +65,7 @@ class SpdyZlibEncoder {
         }
     }
 
+    @Override
     public void end() {
         compressor.end();
     }

pom.xml

@@ -212,9 +212,9 @@
             <configuration>
               <rules>
                 <requireJavaVersion>
-                  <!-- Enforce java 1.6 as minimum for compiling -->
+                  <!-- Enforce java 1.7 as minimum for compiling -->
-                  <!-- This is needed because of the Unsafe detection code -->
+                  <!-- This is needed because of java.util.zip.Deflater -->
-                  <version>[1.6.0,)</version>
+                  <version>[1.7.0,)</version>
                 </requireJavaVersion>
                 <requireMavenVersion>
                   <version>[3.0.2,)</version>
@@ -237,6 +237,32 @@
           <showWarnings>true</showWarnings>
         </configuration>
       </plugin>
+      <plugin>
+        <!-- ensure that only methods available in java 1.6 can
+             be used even when compiling with java 1.7+ -->
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>animal-sniffer-maven-plugin</artifactId>
+        <version>1.7</version>
+        <configuration>
+          <signature>
+            <groupId>org.codehaus.mojo.signature</groupId>
+            <artifactId>java16</artifactId>
+            <version>1.0</version>
+          </signature>
+          <ignores>
+            <ignore>sun.misc.Unsafe</ignore>
+            <ignore>java.util.zip.Deflater</ignore>
+          </ignores>
+        </configuration>
+        <executions>
+          <execution>
+            <phase>process-classes</phase>
+            <goals>
+              <goal>check</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
       <plugin>
         <artifactId>maven-checkstyle-plugin</artifactId>
         <version>2.8</version>

src/main/java/org/jboss/netty/handler/codec/spdy/SpdyZlibEncoder.java

@@ -1,69 +0,0 @@
-/*
- * Copyright 2012 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-/*
- * Copyright 2012 Twitter, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may
- * not use this file except in compliance with the License. You may obtain
- * a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package org.jboss.netty.handler.codec.spdy;
-
-import java.util.zip.Deflater;
-
-import org.jboss.netty.buffer.ChannelBuffer;
-
-import static org.jboss.netty.handler.codec.spdy.SpdyCodecUtil.*;
-
-class SpdyZlibEncoder {
-
-    private final byte[] out = new byte[8192];
-    private final Deflater compressor;
-
-    public SpdyZlibEncoder(int compressionLevel) {
-        if (compressionLevel < 0 || compressionLevel > 9) {
-            throw new IllegalArgumentException(
-                    "compressionLevel: " + compressionLevel + " (expected: 0-9)");
-        }
-        compressor = new Deflater(compressionLevel);
-        compressor.setDictionary(SPDY_DICT);
-    }
-
-    public void setInput(ChannelBuffer decompressed) {
-        byte[] in = new byte[decompressed.readableBytes()];
-        decompressed.readBytes(in);
-        compressor.setInput(in);
-    }
-
-    public void encode(ChannelBuffer compressed) {
-        while (!compressor.needsInput()) {
-            int numBytes = compressor.deflate(out, 0, out.length, Deflater.SYNC_FLUSH);
-            compressed.writeBytes(out, 0, numBytes);
-        }
-    }
-
-    public void end() {
-        compressor.end();
-    }
-}