1 /* 2 * Copyright 2016 The gRPC Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package io.grpc.netty; 18 19 import io.netty.handler.codec.http2.Http2Headers; 20 import io.netty.util.AsciiString; 21 import java.util.Iterator; 22 import java.util.Map; 23 import java.util.NoSuchElementException; 24 25 /** 26 * A custom implementation of Http2Headers that only includes methods used by gRPC. 27 */ 28 final class GrpcHttp2OutboundHeaders extends AbstractHttp2Headers { 29 30 private final AsciiString[] normalHeaders; 31 private final AsciiString[] preHeaders; 32 private static final AsciiString[] EMPTY = new AsciiString[]{}; 33 clientRequestHeaders(byte[][] serializedMetadata, AsciiString authority, AsciiString path, AsciiString method, AsciiString scheme, AsciiString userAgent)34 static GrpcHttp2OutboundHeaders clientRequestHeaders(byte[][] serializedMetadata, 35 AsciiString authority, AsciiString path, AsciiString method, AsciiString scheme, 36 AsciiString userAgent) { 37 AsciiString[] preHeaders = new AsciiString[] { 38 Http2Headers.PseudoHeaderName.AUTHORITY.value(), authority, 39 Http2Headers.PseudoHeaderName.PATH.value(), path, 40 Http2Headers.PseudoHeaderName.METHOD.value(), method, 41 Http2Headers.PseudoHeaderName.SCHEME.value(), scheme, 42 Utils.CONTENT_TYPE_HEADER, Utils.CONTENT_TYPE_GRPC, 43 Utils.TE_HEADER, Utils.TE_TRAILERS, 44 Utils.USER_AGENT, userAgent, 45 }; 46 return new GrpcHttp2OutboundHeaders(preHeaders, serializedMetadata); 47 } 48 serverResponseHeaders(byte[][] serializedMetadata)49 static GrpcHttp2OutboundHeaders serverResponseHeaders(byte[][] serializedMetadata) { 50 AsciiString[] preHeaders = new AsciiString[] { 51 Http2Headers.PseudoHeaderName.STATUS.value(), Utils.STATUS_OK, 52 Utils.CONTENT_TYPE_HEADER, Utils.CONTENT_TYPE_GRPC, 53 }; 54 return new GrpcHttp2OutboundHeaders(preHeaders, serializedMetadata); 55 } 56 serverResponseTrailers(byte[][] serializedMetadata)57 static GrpcHttp2OutboundHeaders serverResponseTrailers(byte[][] serializedMetadata) { 58 return new GrpcHttp2OutboundHeaders(EMPTY, serializedMetadata); 59 } 60 GrpcHttp2OutboundHeaders(AsciiString[] preHeaders, byte[][] serializedMetadata)61 private GrpcHttp2OutboundHeaders(AsciiString[] preHeaders, byte[][] serializedMetadata) { 62 normalHeaders = new AsciiString[serializedMetadata.length]; 63 for (int i = 0; i < normalHeaders.length; i++) { 64 normalHeaders[i] = new AsciiString(serializedMetadata[i], false); 65 } 66 this.preHeaders = preHeaders; 67 } 68 69 @Override 70 @SuppressWarnings("ReferenceEquality") // STATUS.value() never changes. status()71 public CharSequence status() { 72 // preHeaders is never null. It has status as the first element or not at all. 73 if (preHeaders.length >= 2 && preHeaders[0] == Http2Headers.PseudoHeaderName.STATUS.value()) { 74 return preHeaders[1]; 75 } 76 return null; 77 } 78 79 @Override iterator()80 public Iterator<Map.Entry<CharSequence, CharSequence>> iterator() { 81 return new Itr(); 82 } 83 84 @Override size()85 public int size() { 86 return (normalHeaders.length + preHeaders.length) / 2; 87 } 88 89 private class Itr implements Map.Entry<CharSequence, CharSequence>, 90 Iterator<Map.Entry<CharSequence, CharSequence>> { 91 private int idx; 92 private AsciiString[] current = preHeaders.length != 0 ? preHeaders : normalHeaders; 93 private AsciiString key; 94 private AsciiString value; 95 96 @Override hasNext()97 public boolean hasNext() { 98 return idx < current.length; 99 } 100 101 /** 102 * This function is ordered specifically to get ideal performance on OpenJDK. If you decide to 103 * change it, even in ways that don't seem possible to affect performance, please benchmark 104 * speeds before and after. 105 */ 106 @Override next()107 public Map.Entry<CharSequence, CharSequence> next() { 108 if (hasNext()) { 109 key = current[idx]; 110 value = current[idx + 1]; 111 idx += 2; 112 if (idx >= current.length && current == preHeaders) { 113 current = normalHeaders; 114 idx = 0; 115 } 116 return this; 117 } else { 118 throw new NoSuchElementException(); 119 } 120 } 121 122 @Override getKey()123 public CharSequence getKey() { 124 return key; 125 } 126 127 @Override getValue()128 public CharSequence getValue() { 129 return value; 130 } 131 132 @Override setValue(CharSequence value)133 public CharSequence setValue(CharSequence value) { 134 throw new UnsupportedOperationException(); 135 } 136 137 @Override remove()138 public void remove() { 139 throw new UnsupportedOperationException(); 140 } 141 } 142 143 @Override toString()144 public String toString() { 145 StringBuilder builder = new StringBuilder(getClass().getSimpleName()).append('['); 146 String separator = ""; 147 for (Map.Entry<CharSequence, CharSequence> e : this) { 148 CharSequence name = e.getKey(); 149 CharSequence value = e.getValue(); 150 builder.append(separator); 151 builder.append(name).append(": ").append(value); 152 separator = ", "; 153 } 154 builder.append(']'); 155 return builder.toString(); 156 } 157 } 158