First cut of frame encoding/decoding and session management for HTTP2

Motivation:

Needed a rough performance comparison between SPDY and HTTP 2.0 framing.
Expected performance gains were seen in HTTP 2.0 due to header
compression.

Modifications:

Added a new codec-http2 module containing all of the new source and unit
tests.  Updated the top-level pom.xml to add this as a child module.

Result:

Netty will have basic support for HTTP2.

codec-http2/pom.xml

@@ -0,0 +1,61 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright 2014 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.
+  -->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>io.netty</groupId>
+    <artifactId>netty-parent</artifactId>
+    <version>5.0.0.Alpha2-SNAPSHOT</version>
+  </parent>
+
+  <artifactId>netty-codec-http2</artifactId>
+  <packaging>jar</packaging>
+
+  <name>Netty/Codec/HTTP2</name>
+
+  <dependencies>
+    <dependency>
+      <groupId>${project.groupId}</groupId>
+      <artifactId>netty-codec-http</artifactId>
+      <version>${project.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>${project.groupId}</groupId>
+      <artifactId>netty-handler</artifactId>
+      <version>${project.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>com.twitter</groupId>
+      <artifactId>hpack</artifactId>
+      <version>0.6.0</version>
+    </dependency>
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava</artifactId>
+      <version>16.0.1</version>
+    </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-all</artifactId>
+      <version>1.9.5</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+</project>
+

codec-http2/src/main/java/io/netty/handler/codec/http2/draft10/Http2Error.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2014 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.http2.draft10;
+
+/**
+ * All error codes identified by the HTTP2 spec.
+ */
+public enum Http2Error {
+  NO_ERROR(0),
+  PROTOCOL_ERROR(1),
+  INTERNAL_ERROR(2),
+  FLOW_CONTROL_ERROR(3),
+  SETTINGS_TIMEOUT(4),
+  STREAM_CLOSED(5),
+  FRAME_SIZE_ERROR(6),
+  REFUSED_STREAM(7),
+  CANCEL(8),
+  COMPRESSION_ERROR(9),
+  CONNECT_ERROR(10),
+  ENHANCE_YOUR_CALM(11),
+  INADEQUATE_SECURITY(12);
+
+  private final int code;
+
+  private Http2Error(int code) {
+    this.code = code;
+  }
+
+  public int getCode() {
+    return this.code;
+  }
+}

codec-http2/src/main/java/io/netty/handler/codec/http2/draft10/Http2Exception.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2014 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.http2.draft10;
+
+/**
+ * Exception thrown when an HTTP2 error was encountered.
+ */
+public class Http2Exception extends Exception {
+  private static final long serialVersionUID = -2292608019080068769L;
+
+  private final Http2Error error;
+
+  public Http2Exception(Http2Error error) {
+    this.error = error;
+  }
+
+  public Http2Exception(Http2Error error, String message) {
+    super(message);
+    this.error = error;
+  }
+
+  public Http2Error getError() {
+    return error;
+  }
+
+  public static Http2Exception format(Http2Error error, String fmt, Object... args) {
+    return new Http2Exception(error, String.format(fmt, args));
+  }
+
+  public static Http2Exception protocolError(String fmt, Object... args) {
+    return format(Http2Error.PROTOCOL_ERROR, fmt, args);
+  }
+
+  public static Http2Exception flowControlError(String fmt, Object... args) {
+    return format(Http2Error.FLOW_CONTROL_ERROR, fmt, args);
+  }
+}

codec-http2/src/main/java/io/netty/handler/codec/http2/draft10/Http2Headers.java

@@ -0,0 +1,193 @@
+/*
+ * Copyright 2014 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.http2.draft10;
+
+import java.util.Iterator;
+import java.util.Map.Entry;
+
+import com.google.common.base.Charsets;
+import com.google.common.collect.ImmutableCollection;
+import com.google.common.collect.ImmutableMultimap;
+
+public final class Http2Headers implements Iterable<Entry<String, String>> {
+
+    /**
+     * HTTP2 header names.
+     */
+    public enum HttpName {
+        /**
+         * {@code :method}.
+         */
+        METHOD(":method"),
+
+        /**
+         * {@code :scheme}.
+         */
+        SCHEME(":scheme"),
+
+        /**
+         * {@code :authority}.
+         */
+        AUTHORITY(":authority"),
+
+        /**
+         * {@code :path}.
+         */
+        PATH(":path"),
+
+        /**
+         * {@code :status}.
+         */
+        STATUS(":status");
+
+        private final String value;
+
+        private HttpName(String value) {
+            this.value = value;
+        }
+
+        public String value() {
+            return this.value;
+        }
+    }
+
+    private final ImmutableMultimap<String, String> headers;
+
+    private Http2Headers(Builder builder) {
+        this.headers = builder.map.build();
+    }
+
+    public String getHeader(String name) {
+        ImmutableCollection<String> col = getHeaders(name);
+        return col.isEmpty() ? null : col.iterator().next();
+    }
+
+    public ImmutableCollection<String> getHeaders(String name) {
+        return headers.get(name);
+    }
+
+    public String getMethod() {
+        return getHeader(HttpName.METHOD.value());
+    }
+
+    public String getScheme() {
+        return getHeader(HttpName.SCHEME.value());
+    }
+
+    public String getAuthority() {
+        return getHeader(HttpName.AUTHORITY.value());
+    }
+
+    public String getPath() {
+        return getHeader(HttpName.PATH.value());
+    }
+
+    public String getStatus() {
+        return getHeader(HttpName.STATUS.value());
+    }
+
+    @Override
+    public Iterator<Entry<String, String>> iterator() {
+        return headers.entries().iterator();
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((headers == null) ? 0 : headers.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) {
+            return true;
+        }
+        if (obj == null) {
+            return false;
+        }
+        if (getClass() != obj.getClass()) {
+            return false;
+        }
+        Http2Headers other = (Http2Headers) obj;
+        if (headers == null) {
+            if (other.headers != null) {
+                return false;
+            }
+        } else if (!headers.equals(other.headers)) {
+            return false;
+        }
+        return true;
+    }
+
+    @Override
+    public String toString() {
+        return headers.toString();
+    }
+
+    public static class Builder {
+        private ImmutableMultimap.Builder<String, String> map = ImmutableMultimap.builder();
+
+        public Builder clear() {
+            map = ImmutableMultimap.builder();
+            return this;
+        }
+
+        public Builder addHeaders(Http2Headers headers) {
+            if (headers == null) {
+                throw new IllegalArgumentException("headers must not be null.");
+            }
+            map.putAll(headers.headers);
+            return this;
+        }
+
+        public Builder addHeader(String name, String value) {
+            // Use interning on the header name to save space.
+            map.put(name.intern(), value);
+            return this;
+        }
+
+        public Builder addHeader(byte[] name, byte[] value) {
+            addHeader(new String(name, Charsets.UTF_8), new String(value, Charsets.UTF_8));
+            return this;
+        }
+
+        public Builder setMethod(String value) {
+            return addHeader(HttpName.METHOD.value(), value);
+        }
+
+        public Builder setScheme(String value) {
+            return addHeader(HttpName.SCHEME.value(), value);
+        }
+
+        public Builder setAuthority(String value) {
+            return addHeader(HttpName.AUTHORITY.value(), value);
+        }
+
+        public Builder setPath(String value) {
+            return addHeader(HttpName.PATH.value(), value);
+        }
+
+        public Builder setStatus(String value) {
+            return addHeader(HttpName.STATUS.value(), value);
+        }
+
+        public Http2Headers build() {
+            return new Http2Headers(this);
+        }
+    }
+}

codec-http2/src/main/java/io/netty/handler/codec/http2/draft10/Http2StreamException.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2014 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.http2.draft10;
+
+public class Http2StreamException extends Http2Exception {
+
+  private static final long serialVersionUID = -7658235659648480024L;
+  private final int streamId;
+
+  public Http2StreamException(int streamId, Http2Error error, String message) {
+    super(error, message);
+    this.streamId = streamId;
+  }
+
+  public Http2StreamException(int streamId, Http2Error error) {
+    super(error);
+    this.streamId = streamId;
+  }
+
+  public int getStreamId() {
+    return streamId;
+  }
+}