1 /* 2 * Copyright 2014 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.internal; 18 19 import static com.google.common.base.Charsets.UTF_8; 20 21 import com.google.common.base.Preconditions; 22 import io.grpc.KnownLength; 23 import java.io.IOException; 24 import java.io.InputStream; 25 import java.io.OutputStream; 26 import java.nio.ByteBuffer; 27 import java.nio.charset.Charset; 28 29 /** 30 * Utility methods for creating {@link ReadableBuffer} instances. 31 */ 32 public final class ReadableBuffers { 33 private static final ReadableBuffer EMPTY_BUFFER = new ByteArrayWrapper(new byte[0]); 34 35 /** 36 * Returns an empty {@link ReadableBuffer} instance. 37 */ 38 public static ReadableBuffer empty() { 39 return EMPTY_BUFFER; 40 } 41 42 /** 43 * Shortcut for {@code wrap(bytes, 0, bytes.length}. 44 */ 45 public static ReadableBuffer wrap(byte[] bytes) { 46 return new ByteArrayWrapper(bytes, 0, bytes.length); 47 } 48 49 /** 50 * Creates a new {@link ReadableBuffer} that is backed by the given byte array. 51 * 52 * @param bytes the byte array being wrapped. 53 * @param offset the starting offset for the buffer within the byte array. 54 * @param length the length of the buffer from the {@code offset} index. 55 */ 56 public static ReadableBuffer wrap(byte[] bytes, int offset, int length) { 57 return new ByteArrayWrapper(bytes, offset, length); 58 } 59 60 /** 61 * Creates a new {@link ReadableBuffer} that is backed by the given {@link ByteBuffer}. Calls to 62 * read from the buffer will increment the position of the {@link ByteBuffer}. 63 */ 64 public static ReadableBuffer wrap(ByteBuffer bytes) { 65 return new ByteReadableBufferWrapper(bytes); 66 } 67 68 /** 69 * Reads an entire {@link ReadableBuffer} to a new array. After calling this method, the buffer 70 * will contain no readable bytes. 71 */ 72 public static byte[] readArray(ReadableBuffer buffer) { 73 Preconditions.checkNotNull(buffer, "buffer"); 74 int length = buffer.readableBytes(); 75 byte[] bytes = new byte[length]; 76 buffer.readBytes(bytes, 0, length); 77 return bytes; 78 } 79 80 /** 81 * Reads the entire {@link ReadableBuffer} to a new {@link String} with the given charset. 82 */ 83 public static String readAsString(ReadableBuffer buffer, Charset charset) { 84 Preconditions.checkNotNull(charset, "charset"); 85 byte[] bytes = readArray(buffer); 86 return new String(bytes, charset); 87 } 88 89 /** 90 * Reads the entire {@link ReadableBuffer} to a new {@link String} using UTF-8 decoding. 91 */ 92 public static String readAsStringUtf8(ReadableBuffer buffer) { 93 return readAsString(buffer, UTF_8); 94 } 95 96 /** 97 * Creates a new {@link InputStream} backed by the given buffer. Any read taken on the stream will 98 * automatically increment the read position of this buffer. Closing the stream, however, does not 99 * affect the original buffer. 100 * 101 * @param buffer the buffer backing the new {@link InputStream}. 102 * @param owner if {@code true}, the returned stream will close the buffer when closed. 103 */ 104 public static InputStream openStream(ReadableBuffer buffer, boolean owner) { 105 return new BufferInputStream(owner ? buffer : ignoreClose(buffer)); 106 } 107 108 /** 109 * Decorates the given {@link ReadableBuffer} to ignore calls to {@link ReadableBuffer#close}. 110 * 111 * @param buffer the buffer to be decorated. 112 * @return a wrapper around {@code buffer} that ignores calls to {@link ReadableBuffer#close}. 113 */ 114 public static ReadableBuffer ignoreClose(ReadableBuffer buffer) { 115 return new ForwardingReadableBuffer(buffer) { 116 @Override 117 public void close() { 118 // Ignore. 119 } 120 }; 121 } 122 123 /** 124 * A {@link ReadableBuffer} that is backed by a byte array. 125 */ 126 private static class ByteArrayWrapper extends AbstractReadableBuffer { 127 int offset; 128 final int end; 129 final byte[] bytes; 130 131 ByteArrayWrapper(byte[] bytes) { 132 this(bytes, 0, bytes.length); 133 } 134 135 ByteArrayWrapper(byte[] bytes, int offset, int length) { 136 Preconditions.checkArgument(offset >= 0, "offset must be >= 0"); 137 Preconditions.checkArgument(length >= 0, "length must be >= 0"); 138 Preconditions.checkArgument(offset + length <= bytes.length, 139 "offset + length exceeds array boundary"); 140 this.bytes = Preconditions.checkNotNull(bytes, "bytes"); 141 this.offset = offset; 142 this.end = offset + length; 143 } 144 145 @Override 146 public int readableBytes() { 147 return end - offset; 148 } 149 150 @Override 151 public void skipBytes(int length) { 152 checkReadable(length); 153 offset += length; 154 } 155 156 @Override 157 public int readUnsignedByte() { 158 checkReadable(1); 159 return bytes[offset++] & 0xFF; 160 } 161 162 @Override 163 public void readBytes(byte[] dest, int destIndex, int length) { 164 System.arraycopy(bytes, offset, dest, destIndex, length); 165 offset += length; 166 } 167 168 @Override 169 public void readBytes(ByteBuffer dest) { 170 Preconditions.checkNotNull(dest, "dest"); 171 int length = dest.remaining(); 172 checkReadable(length); 173 dest.put(bytes, offset, length); 174 offset += length; 175 } 176 177 @Override 178 public void readBytes(OutputStream dest, int length) throws IOException { 179 checkReadable(length); 180 dest.write(bytes, offset, length); 181 offset += length; 182 } 183 184 @Override 185 public ByteArrayWrapper readBytes(int length) { 186 checkReadable(length); 187 int originalOffset = offset; 188 offset += length; 189 return new ByteArrayWrapper(bytes, originalOffset, length); 190 } 191 192 @Override 193 public boolean hasArray() { 194 return true; 195 } 196 197 @Override 198 public byte[] array() { 199 return bytes; 200 } 201 202 @Override 203 public int arrayOffset() { 204 return offset; 205 } 206 } 207 208 /** 209 * A {@link ReadableBuffer} that is backed by a {@link ByteBuffer}. 210 */ 211 private static class ByteReadableBufferWrapper extends AbstractReadableBuffer { 212 final ByteBuffer bytes; 213 214 ByteReadableBufferWrapper(ByteBuffer bytes) { 215 this.bytes = Preconditions.checkNotNull(bytes, "bytes"); 216 } 217 218 @Override 219 public int readableBytes() { 220 return bytes.remaining(); 221 } 222 223 @Override 224 public int readUnsignedByte() { 225 checkReadable(1); 226 return bytes.get() & 0xFF; 227 } 228 229 @Override 230 public void skipBytes(int length) { 231 checkReadable(length); 232 bytes.position(bytes.position() + length); 233 } 234 235 @Override 236 public void readBytes(byte[] dest, int destOffset, int length) { 237 checkReadable(length); 238 bytes.get(dest, destOffset, length); 239 } 240 241 @Override 242 public void readBytes(ByteBuffer dest) { 243 Preconditions.checkNotNull(dest, "dest"); 244 int length = dest.remaining(); 245 checkReadable(length); 246 247 // Change the limit so that only length bytes are available. 248 int prevLimit = bytes.limit(); 249 bytes.limit(bytes.position() + length); 250 251 // Write the bytes and restore the original limit. 252 dest.put(bytes); 253 bytes.limit(prevLimit); 254 } 255 256 @Override 257 public void readBytes(OutputStream dest, int length) throws IOException { 258 checkReadable(length); 259 if (hasArray()) { 260 dest.write(array(), arrayOffset(), length); 261 bytes.position(bytes.position() + length); 262 } else { 263 // The buffer doesn't support array(). Copy the data to an intermediate buffer. 264 byte[] array = new byte[length]; 265 bytes.get(array); 266 dest.write(array); 267 } 268 } 269 270 @Override 271 public ByteReadableBufferWrapper readBytes(int length) { 272 checkReadable(length); 273 ByteBuffer buffer = bytes.duplicate(); 274 buffer.limit(bytes.position() + length); 275 bytes.position(bytes.position() + length); 276 return new ByteReadableBufferWrapper(buffer); 277 } 278 279 @Override 280 public boolean hasArray() { 281 return bytes.hasArray(); 282 } 283 284 @Override 285 public byte[] array() { 286 return bytes.array(); 287 } 288 289 @Override 290 public int arrayOffset() { 291 return bytes.arrayOffset() + bytes.position(); 292 } 293 } 294 295 /** 296 * An {@link InputStream} that is backed by a {@link ReadableBuffer}. 297 */ 298 private static final class BufferInputStream extends InputStream implements KnownLength { 299 final ReadableBuffer buffer; 300 301 public BufferInputStream(ReadableBuffer buffer) { 302 this.buffer = Preconditions.checkNotNull(buffer, "buffer"); 303 } 304 305 @Override 306 public int available() throws IOException { 307 return buffer.readableBytes(); 308 } 309 310 @Override 311 public int read() { 312 if (buffer.readableBytes() == 0) { 313 // EOF. 314 return -1; 315 } 316 return buffer.readUnsignedByte(); 317 } 318 319 @Override 320 public int read(byte[] dest, int destOffset, int length) throws IOException { 321 if (buffer.readableBytes() == 0) { 322 // EOF. 323 return -1; 324 } 325 326 length = Math.min(buffer.readableBytes(), length); 327 buffer.readBytes(dest, destOffset, length); 328 return length; 329 } 330 331 @Override 332 public void close() throws IOException { 333 buffer.close(); 334 } 335 } 336 337 private ReadableBuffers() {} 338 } 339