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<pre><span class="sourceLineNo">001</span>/**<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Licensed to the Apache Software Foundation (ASF) under one<a name="line.2"></a>
<span class="sourceLineNo">003</span> * or more contributor license agreements. See the NOTICE file<a name="line.3"></a>
<span class="sourceLineNo">004</span> * distributed with this work for additional information<a name="line.4"></a>
<span class="sourceLineNo">005</span> * regarding copyright ownership. The ASF licenses this file<a name="line.5"></a>
<span class="sourceLineNo">006</span> * to you under the Apache License, Version 2.0 (the<a name="line.6"></a>
<span class="sourceLineNo">007</span> * "License"); you may not use this file except in compliance<a name="line.7"></a>
<span class="sourceLineNo">008</span> * with the License. You may obtain a copy of the License at<a name="line.8"></a>
<span class="sourceLineNo">009</span> *<a name="line.9"></a>
<span class="sourceLineNo">010</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.10"></a>
<span class="sourceLineNo">011</span> *<a name="line.11"></a>
<span class="sourceLineNo">012</span> * Unless required by applicable law or agreed to in writing, software<a name="line.12"></a>
<span class="sourceLineNo">013</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.13"></a>
<span class="sourceLineNo">014</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.14"></a>
<span class="sourceLineNo">015</span> * See the License for the specific language governing permissions and<a name="line.15"></a>
<span class="sourceLineNo">016</span> * limitations under the License.<a name="line.16"></a>
<span class="sourceLineNo">017</span> */<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>package org.apache.hadoop.hbase.io.util;<a name="line.19"></a>
<span class="sourceLineNo">020</span><a name="line.20"></a>
<span class="sourceLineNo">021</span>import java.io.IOException;<a name="line.21"></a>
<span class="sourceLineNo">022</span>import java.io.InputStream;<a name="line.22"></a>
<span class="sourceLineNo">023</span>import java.lang.reflect.InvocationTargetException;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import java.lang.reflect.Method;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import java.nio.ByteBuffer;<a name="line.25"></a>
<span class="sourceLineNo">026</span><a name="line.26"></a>
<span class="sourceLineNo">027</span>import org.apache.hadoop.fs.ByteBufferReadable;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import org.apache.hadoop.fs.FSDataInputStream;<a name="line.28"></a>
<span class="sourceLineNo">029</span>import org.apache.hadoop.hbase.nio.ByteBuff;<a name="line.29"></a>
<span class="sourceLineNo">030</span>import org.apache.hadoop.io.IOUtils;<a name="line.30"></a>
<span class="sourceLineNo">031</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.31"></a>
<span class="sourceLineNo">032</span>import org.slf4j.Logger;<a name="line.32"></a>
<span class="sourceLineNo">033</span>import org.slf4j.LoggerFactory;<a name="line.33"></a>
<span class="sourceLineNo">034</span><a name="line.34"></a>
<span class="sourceLineNo">035</span>@InterfaceAudience.Private<a name="line.35"></a>
<span class="sourceLineNo">036</span>public final class BlockIOUtils {<a name="line.36"></a>
<span class="sourceLineNo">037</span> private static final Logger LOG =<a name="line.37"></a>
<span class="sourceLineNo">038</span> LoggerFactory.getLogger(BlockIOUtils.class);<a name="line.38"></a>
<span class="sourceLineNo">039</span> // TODO: remove the reflection when we update to Hadoop 3.3 or above.<a name="line.39"></a>
<span class="sourceLineNo">040</span> private static Method byteBufferPositionedReadMethod;<a name="line.40"></a>
<span class="sourceLineNo">041</span><a name="line.41"></a>
<span class="sourceLineNo">042</span> static {<a name="line.42"></a>
<span class="sourceLineNo">043</span> initByteBufferPositionReadableMethod();<a name="line.43"></a>
<span class="sourceLineNo">044</span> }<a name="line.44"></a>
<span class="sourceLineNo">045</span><a name="line.45"></a>
<span class="sourceLineNo">046</span> // Disallow instantiation<a name="line.46"></a>
<span class="sourceLineNo">047</span> private BlockIOUtils() {<a name="line.47"></a>
<span class="sourceLineNo">048</span><a name="line.48"></a>
<span class="sourceLineNo">049</span> }<a name="line.49"></a>
<span class="sourceLineNo">050</span><a name="line.50"></a>
<span class="sourceLineNo">051</span> private static void initByteBufferPositionReadableMethod() {<a name="line.51"></a>
<span class="sourceLineNo">052</span> try {<a name="line.52"></a>
<span class="sourceLineNo">053</span> //long position, ByteBuffer buf<a name="line.53"></a>
<span class="sourceLineNo">054</span> byteBufferPositionedReadMethod = FSDataInputStream.class.getMethod("read", long.class,<a name="line.54"></a>
<span class="sourceLineNo">055</span> ByteBuffer.class);<a name="line.55"></a>
<span class="sourceLineNo">056</span> } catch (NoSuchMethodException e) {<a name="line.56"></a>
<span class="sourceLineNo">057</span> LOG.debug("Unable to find positioned bytebuffer read API of FSDataInputStream. "<a name="line.57"></a>
<span class="sourceLineNo">058</span> + "preadWithExtra() will use a temporary on-heap byte array.");<a name="line.58"></a>
<span class="sourceLineNo">059</span> }<a name="line.59"></a>
<span class="sourceLineNo">060</span> }<a name="line.60"></a>
<span class="sourceLineNo">061</span><a name="line.61"></a>
<span class="sourceLineNo">062</span> public static boolean isByteBufferReadable(FSDataInputStream is) {<a name="line.62"></a>
<span class="sourceLineNo">063</span> InputStream cur = is.getWrappedStream();<a name="line.63"></a>
<span class="sourceLineNo">064</span> for (;;) {<a name="line.64"></a>
<span class="sourceLineNo">065</span> if ((cur instanceof FSDataInputStream)) {<a name="line.65"></a>
<span class="sourceLineNo">066</span> cur = ((FSDataInputStream) cur).getWrappedStream();<a name="line.66"></a>
<span class="sourceLineNo">067</span> } else {<a name="line.67"></a>
<span class="sourceLineNo">068</span> break;<a name="line.68"></a>
<span class="sourceLineNo">069</span> }<a name="line.69"></a>
<span class="sourceLineNo">070</span> }<a name="line.70"></a>
<span class="sourceLineNo">071</span> return cur instanceof ByteBufferReadable;<a name="line.71"></a>
<span class="sourceLineNo">072</span> }<a name="line.72"></a>
<span class="sourceLineNo">073</span><a name="line.73"></a>
<span class="sourceLineNo">074</span> /**<a name="line.74"></a>
<span class="sourceLineNo">075</span> * Read length bytes into ByteBuffers directly.<a name="line.75"></a>
<span class="sourceLineNo">076</span> * @param buf the destination {@link ByteBuff}<a name="line.76"></a>
<span class="sourceLineNo">077</span> * @param dis the HDFS input stream which implement the ByteBufferReadable interface.<a name="line.77"></a>
<span class="sourceLineNo">078</span> * @param length bytes to read.<a name="line.78"></a>
<span class="sourceLineNo">079</span> * @throws IOException exception to throw if any error happen<a name="line.79"></a>
<span class="sourceLineNo">080</span> */<a name="line.80"></a>
<span class="sourceLineNo">081</span> public static void readFully(ByteBuff buf, FSDataInputStream dis, int length) throws IOException {<a name="line.81"></a>
<span class="sourceLineNo">082</span> if (!isByteBufferReadable(dis)) {<a name="line.82"></a>
<span class="sourceLineNo">083</span> // If InputStream does not support the ByteBuffer read, just read to heap and copy bytes to<a name="line.83"></a>
<span class="sourceLineNo">084</span> // the destination ByteBuff.<a name="line.84"></a>
<span class="sourceLineNo">085</span> byte[] heapBuf = new byte[length];<a name="line.85"></a>
<span class="sourceLineNo">086</span> IOUtils.readFully(dis, heapBuf, 0, length);<a name="line.86"></a>
<span class="sourceLineNo">087</span> copyToByteBuff(heapBuf, 0, length, buf);<a name="line.87"></a>
<span class="sourceLineNo">088</span> return;<a name="line.88"></a>
<span class="sourceLineNo">089</span> }<a name="line.89"></a>
<span class="sourceLineNo">090</span> ByteBuffer[] buffers = buf.nioByteBuffers();<a name="line.90"></a>
<span class="sourceLineNo">091</span> int remain = length;<a name="line.91"></a>
<span class="sourceLineNo">092</span> int idx = 0;<a name="line.92"></a>
<span class="sourceLineNo">093</span> ByteBuffer cur = buffers[idx];<a name="line.93"></a>
<span class="sourceLineNo">094</span> while (remain &gt; 0) {<a name="line.94"></a>
<span class="sourceLineNo">095</span> while (!cur.hasRemaining()) {<a name="line.95"></a>
<span class="sourceLineNo">096</span> if (++idx &gt;= buffers.length) {<a name="line.96"></a>
<span class="sourceLineNo">097</span> throw new IOException(<a name="line.97"></a>
<span class="sourceLineNo">098</span> "Not enough ByteBuffers to read the reminding " + remain + " " + "bytes");<a name="line.98"></a>
<span class="sourceLineNo">099</span> }<a name="line.99"></a>
<span class="sourceLineNo">100</span> cur = buffers[idx];<a name="line.100"></a>
<span class="sourceLineNo">101</span> }<a name="line.101"></a>
<span class="sourceLineNo">102</span> cur.limit(cur.position() + Math.min(remain, cur.remaining()));<a name="line.102"></a>
<span class="sourceLineNo">103</span> int bytesRead = dis.read(cur);<a name="line.103"></a>
<span class="sourceLineNo">104</span> if (bytesRead &lt; 0) {<a name="line.104"></a>
<span class="sourceLineNo">105</span> throw new IOException(<a name="line.105"></a>
<span class="sourceLineNo">106</span> "Premature EOF from inputStream, but still need " + remain + " " + "bytes");<a name="line.106"></a>
<span class="sourceLineNo">107</span> }<a name="line.107"></a>
<span class="sourceLineNo">108</span> remain -= bytesRead;<a name="line.108"></a>
<span class="sourceLineNo">109</span> }<a name="line.109"></a>
<span class="sourceLineNo">110</span> }<a name="line.110"></a>
<span class="sourceLineNo">111</span><a name="line.111"></a>
<span class="sourceLineNo">112</span> /**<a name="line.112"></a>
<span class="sourceLineNo">113</span> * Copying bytes from InputStream to {@link ByteBuff} by using an temporary heap byte[] (default<a name="line.113"></a>
<span class="sourceLineNo">114</span> * size is 1024 now).<a name="line.114"></a>
<span class="sourceLineNo">115</span> * @param in the InputStream to read<a name="line.115"></a>
<span class="sourceLineNo">116</span> * @param out the destination {@link ByteBuff}<a name="line.116"></a>
<span class="sourceLineNo">117</span> * @param length to read<a name="line.117"></a>
<span class="sourceLineNo">118</span> * @throws IOException if any io error encountered.<a name="line.118"></a>
<span class="sourceLineNo">119</span> */<a name="line.119"></a>
<span class="sourceLineNo">120</span> public static void readFullyWithHeapBuffer(InputStream in, ByteBuff out, int length)<a name="line.120"></a>
<span class="sourceLineNo">121</span> throws IOException {<a name="line.121"></a>
<span class="sourceLineNo">122</span> byte[] buffer = new byte[1024];<a name="line.122"></a>
<span class="sourceLineNo">123</span> if (length &lt; 0) {<a name="line.123"></a>
<span class="sourceLineNo">124</span> throw new IllegalArgumentException("Length must not be negative: " + length);<a name="line.124"></a>
<span class="sourceLineNo">125</span> }<a name="line.125"></a>
<span class="sourceLineNo">126</span> int remain = length, count;<a name="line.126"></a>
<span class="sourceLineNo">127</span> while (remain &gt; 0) {<a name="line.127"></a>
<span class="sourceLineNo">128</span> count = in.read(buffer, 0, Math.min(remain, buffer.length));<a name="line.128"></a>
<span class="sourceLineNo">129</span> if (count &lt; 0) {<a name="line.129"></a>
<span class="sourceLineNo">130</span> throw new IOException(<a name="line.130"></a>
<span class="sourceLineNo">131</span> "Premature EOF from inputStream, but still need " + remain + " bytes");<a name="line.131"></a>
<span class="sourceLineNo">132</span> }<a name="line.132"></a>
<span class="sourceLineNo">133</span> out.put(buffer, 0, count);<a name="line.133"></a>
<span class="sourceLineNo">134</span> remain -= count;<a name="line.134"></a>
<span class="sourceLineNo">135</span> }<a name="line.135"></a>
<span class="sourceLineNo">136</span> }<a name="line.136"></a>
<span class="sourceLineNo">137</span><a name="line.137"></a>
<span class="sourceLineNo">138</span> /**<a name="line.138"></a>
<span class="sourceLineNo">139</span> * Read from an input stream at least &lt;code&gt;necessaryLen&lt;/code&gt; and if possible,<a name="line.139"></a>
<span class="sourceLineNo">140</span> * &lt;code&gt;extraLen&lt;/code&gt; also if available. Analogous to<a name="line.140"></a>
<span class="sourceLineNo">141</span> * {@link IOUtils#readFully(InputStream, byte[], int, int)}, but specifies a number of "extra"<a name="line.141"></a>
<span class="sourceLineNo">142</span> * bytes to also optionally read.<a name="line.142"></a>
<span class="sourceLineNo">143</span> * @param in the input stream to read from<a name="line.143"></a>
<span class="sourceLineNo">144</span> * @param buf the buffer to read into<a name="line.144"></a>
<span class="sourceLineNo">145</span> * @param bufOffset the destination offset in the buffer<a name="line.145"></a>
<span class="sourceLineNo">146</span> * @param necessaryLen the number of bytes that are absolutely necessary to read<a name="line.146"></a>
<span class="sourceLineNo">147</span> * @param extraLen the number of extra bytes that would be nice to read<a name="line.147"></a>
<span class="sourceLineNo">148</span> * @return true if succeeded reading the extra bytes<a name="line.148"></a>
<span class="sourceLineNo">149</span> * @throws IOException if failed to read the necessary bytes<a name="line.149"></a>
<span class="sourceLineNo">150</span> */<a name="line.150"></a>
<span class="sourceLineNo">151</span> private static boolean readWithExtraOnHeap(InputStream in, byte[] buf, int bufOffset,<a name="line.151"></a>
<span class="sourceLineNo">152</span> int necessaryLen, int extraLen) throws IOException {<a name="line.152"></a>
<span class="sourceLineNo">153</span> int bytesRemaining = necessaryLen + extraLen;<a name="line.153"></a>
<span class="sourceLineNo">154</span> while (bytesRemaining &gt; 0) {<a name="line.154"></a>
<span class="sourceLineNo">155</span> int ret = in.read(buf, bufOffset, bytesRemaining);<a name="line.155"></a>
<span class="sourceLineNo">156</span> if (ret &lt; 0) {<a name="line.156"></a>
<span class="sourceLineNo">157</span> if (bytesRemaining &lt;= extraLen) {<a name="line.157"></a>
<span class="sourceLineNo">158</span> // We could not read the "extra data", but that is OK.<a name="line.158"></a>
<span class="sourceLineNo">159</span> break;<a name="line.159"></a>
<span class="sourceLineNo">160</span> }<a name="line.160"></a>
<span class="sourceLineNo">161</span> throw new IOException("Premature EOF from inputStream (read " + "returned " + ret<a name="line.161"></a>
<span class="sourceLineNo">162</span> + ", was trying to read " + necessaryLen + " necessary bytes and " + extraLen<a name="line.162"></a>
<span class="sourceLineNo">163</span> + " extra bytes, " + "successfully read " + (necessaryLen + extraLen - bytesRemaining));<a name="line.163"></a>
<span class="sourceLineNo">164</span> }<a name="line.164"></a>
<span class="sourceLineNo">165</span> bufOffset += ret;<a name="line.165"></a>
<span class="sourceLineNo">166</span> bytesRemaining -= ret;<a name="line.166"></a>
<span class="sourceLineNo">167</span> }<a name="line.167"></a>
<span class="sourceLineNo">168</span> return bytesRemaining &lt;= 0;<a name="line.168"></a>
<span class="sourceLineNo">169</span> }<a name="line.169"></a>
<span class="sourceLineNo">170</span><a name="line.170"></a>
<span class="sourceLineNo">171</span> /**<a name="line.171"></a>
<span class="sourceLineNo">172</span> * Read bytes into ByteBuffers directly, those buffers either contains the extraLen bytes or only<a name="line.172"></a>
<span class="sourceLineNo">173</span> * contains necessaryLen bytes, which depends on how much bytes do the last time we read.<a name="line.173"></a>
<span class="sourceLineNo">174</span> * @param buf the destination {@link ByteBuff}.<a name="line.174"></a>
<span class="sourceLineNo">175</span> * @param dis input stream to read.<a name="line.175"></a>
<span class="sourceLineNo">176</span> * @param necessaryLen bytes which we must read<a name="line.176"></a>
<span class="sourceLineNo">177</span> * @param extraLen bytes which we may read<a name="line.177"></a>
<span class="sourceLineNo">178</span> * @return if the returned flag is true, then we've finished to read the extraLen into our<a name="line.178"></a>
<span class="sourceLineNo">179</span> * ByteBuffers, otherwise we've not read the extraLen bytes yet.<a name="line.179"></a>
<span class="sourceLineNo">180</span> * @throws IOException if failed to read the necessary bytes.<a name="line.180"></a>
<span class="sourceLineNo">181</span> */<a name="line.181"></a>
<span class="sourceLineNo">182</span> public static boolean readWithExtra(ByteBuff buf, FSDataInputStream dis, int necessaryLen,<a name="line.182"></a>
<span class="sourceLineNo">183</span> int extraLen) throws IOException {<a name="line.183"></a>
<span class="sourceLineNo">184</span> if (!isByteBufferReadable(dis)) {<a name="line.184"></a>
<span class="sourceLineNo">185</span> // If InputStream does not support the ByteBuffer read, just read to heap and copy bytes to<a name="line.185"></a>
<span class="sourceLineNo">186</span> // the destination ByteBuff.<a name="line.186"></a>
<span class="sourceLineNo">187</span> byte[] heapBuf = new byte[necessaryLen + extraLen];<a name="line.187"></a>
<span class="sourceLineNo">188</span> boolean ret = readWithExtraOnHeap(dis, heapBuf, 0, necessaryLen, extraLen);<a name="line.188"></a>
<span class="sourceLineNo">189</span> copyToByteBuff(heapBuf, 0, heapBuf.length, buf);<a name="line.189"></a>
<span class="sourceLineNo">190</span> return ret;<a name="line.190"></a>
<span class="sourceLineNo">191</span> }<a name="line.191"></a>
<span class="sourceLineNo">192</span> ByteBuffer[] buffers = buf.nioByteBuffers();<a name="line.192"></a>
<span class="sourceLineNo">193</span> int bytesRead = 0;<a name="line.193"></a>
<span class="sourceLineNo">194</span> int remain = necessaryLen + extraLen;<a name="line.194"></a>
<span class="sourceLineNo">195</span> int idx = 0;<a name="line.195"></a>
<span class="sourceLineNo">196</span> ByteBuffer cur = buffers[idx];<a name="line.196"></a>
<span class="sourceLineNo">197</span> while (bytesRead &lt; necessaryLen) {<a name="line.197"></a>
<span class="sourceLineNo">198</span> while (!cur.hasRemaining()) {<a name="line.198"></a>
<span class="sourceLineNo">199</span> if (++idx &gt;= buffers.length) {<a name="line.199"></a>
<span class="sourceLineNo">200</span> throw new IOException("Not enough ByteBuffers to read the reminding " + remain + "bytes");<a name="line.200"></a>
<span class="sourceLineNo">201</span> }<a name="line.201"></a>
<span class="sourceLineNo">202</span> cur = buffers[idx];<a name="line.202"></a>
<span class="sourceLineNo">203</span> }<a name="line.203"></a>
<span class="sourceLineNo">204</span> cur.limit(cur.position() + Math.min(remain, cur.remaining()));<a name="line.204"></a>
<span class="sourceLineNo">205</span> int ret = dis.read(cur);<a name="line.205"></a>
<span class="sourceLineNo">206</span> if (ret &lt; 0) {<a name="line.206"></a>
<span class="sourceLineNo">207</span> throw new IOException("Premature EOF from inputStream (read returned " + ret<a name="line.207"></a>
<span class="sourceLineNo">208</span> + ", was trying to read " + necessaryLen + " necessary bytes and " + extraLen<a name="line.208"></a>
<span class="sourceLineNo">209</span> + " extra bytes, successfully read " + bytesRead);<a name="line.209"></a>
<span class="sourceLineNo">210</span> }<a name="line.210"></a>
<span class="sourceLineNo">211</span> bytesRead += ret;<a name="line.211"></a>
<span class="sourceLineNo">212</span> remain -= ret;<a name="line.212"></a>
<span class="sourceLineNo">213</span> }<a name="line.213"></a>
<span class="sourceLineNo">214</span> return (extraLen &gt; 0) &amp;&amp; (bytesRead == necessaryLen + extraLen);<a name="line.214"></a>
<span class="sourceLineNo">215</span> }<a name="line.215"></a>
<span class="sourceLineNo">216</span><a name="line.216"></a>
<span class="sourceLineNo">217</span> /**<a name="line.217"></a>
<span class="sourceLineNo">218</span> * Read from an input stream at least &lt;code&gt;necessaryLen&lt;/code&gt; and if possible,<a name="line.218"></a>
<span class="sourceLineNo">219</span> * &lt;code&gt;extraLen&lt;/code&gt; also if available. Analogous to<a name="line.219"></a>
<span class="sourceLineNo">220</span> * {@link IOUtils#readFully(InputStream, byte[], int, int)}, but uses positional read and<a name="line.220"></a>
<span class="sourceLineNo">221</span> * specifies a number of "extra" bytes that would be desirable but not absolutely necessary to<a name="line.221"></a>
<span class="sourceLineNo">222</span> * read.<a name="line.222"></a>
<span class="sourceLineNo">223</span> *<a name="line.223"></a>
<span class="sourceLineNo">224</span> * If the input stream supports ByteBufferPositionedReadable, it reads to the byte buffer<a name="line.224"></a>
<span class="sourceLineNo">225</span> * directly, and does not allocate a temporary byte array.<a name="line.225"></a>
<span class="sourceLineNo">226</span> *<a name="line.226"></a>
<span class="sourceLineNo">227</span> * @param buff ByteBuff to read into.<a name="line.227"></a>
<span class="sourceLineNo">228</span> * @param dis the input stream to read from<a name="line.228"></a>
<span class="sourceLineNo">229</span> * @param position the position within the stream from which to start reading<a name="line.229"></a>
<span class="sourceLineNo">230</span> * @param necessaryLen the number of bytes that are absolutely necessary to read<a name="line.230"></a>
<span class="sourceLineNo">231</span> * @param extraLen the number of extra bytes that would be nice to read<a name="line.231"></a>
<span class="sourceLineNo">232</span> * @return true if and only if extraLen is &gt; 0 and reading those extra bytes was successful<a name="line.232"></a>
<span class="sourceLineNo">233</span> * @throws IOException if failed to read the necessary bytes<a name="line.233"></a>
<span class="sourceLineNo">234</span> */<a name="line.234"></a>
<span class="sourceLineNo">235</span> public static boolean preadWithExtra(ByteBuff buff, FSDataInputStream dis, long position,<a name="line.235"></a>
<span class="sourceLineNo">236</span> int necessaryLen, int extraLen) throws IOException {<a name="line.236"></a>
<span class="sourceLineNo">237</span> boolean preadbytebuffer = dis.hasCapability("in:preadbytebuffer");<a name="line.237"></a>
<span class="sourceLineNo">238</span><a name="line.238"></a>
<span class="sourceLineNo">239</span> if (preadbytebuffer) {<a name="line.239"></a>
<span class="sourceLineNo">240</span> return preadWithExtraDirectly(buff, dis, position, necessaryLen, extraLen);<a name="line.240"></a>
<span class="sourceLineNo">241</span> } else {<a name="line.241"></a>
<span class="sourceLineNo">242</span> return preadWithExtraOnHeap(buff, dis, position, necessaryLen, extraLen);<a name="line.242"></a>
<span class="sourceLineNo">243</span> }<a name="line.243"></a>
<span class="sourceLineNo">244</span> }<a name="line.244"></a>
<span class="sourceLineNo">245</span><a name="line.245"></a>
<span class="sourceLineNo">246</span> private static boolean preadWithExtraOnHeap(ByteBuff buff, FSDataInputStream dis, long position,<a name="line.246"></a>
<span class="sourceLineNo">247</span> int necessaryLen, int extraLen) throws IOException {<a name="line.247"></a>
<span class="sourceLineNo">248</span> int remain = necessaryLen + extraLen;<a name="line.248"></a>
<span class="sourceLineNo">249</span> byte[] buf = new byte[remain];<a name="line.249"></a>
<span class="sourceLineNo">250</span> int bytesRead = 0;<a name="line.250"></a>
<span class="sourceLineNo">251</span> while (bytesRead &lt; necessaryLen) {<a name="line.251"></a>
<span class="sourceLineNo">252</span> int ret = dis.read(position + bytesRead, buf, bytesRead, remain);<a name="line.252"></a>
<span class="sourceLineNo">253</span> if (ret &lt; 0) {<a name="line.253"></a>
<span class="sourceLineNo">254</span> throw new IOException("Premature EOF from inputStream (positional read returned " + ret<a name="line.254"></a>
<span class="sourceLineNo">255</span> + ", was trying to read " + necessaryLen + " necessary bytes and " + extraLen<a name="line.255"></a>
<span class="sourceLineNo">256</span> + " extra bytes, successfully read " + bytesRead);<a name="line.256"></a>
<span class="sourceLineNo">257</span> }<a name="line.257"></a>
<span class="sourceLineNo">258</span> bytesRead += ret;<a name="line.258"></a>
<span class="sourceLineNo">259</span> remain -= ret;<a name="line.259"></a>
<span class="sourceLineNo">260</span> }<a name="line.260"></a>
<span class="sourceLineNo">261</span> copyToByteBuff(buf, 0, bytesRead, buff);<a name="line.261"></a>
<span class="sourceLineNo">262</span> return (extraLen &gt; 0) &amp;&amp; (bytesRead == necessaryLen + extraLen);<a name="line.262"></a>
<span class="sourceLineNo">263</span> }<a name="line.263"></a>
<span class="sourceLineNo">264</span><a name="line.264"></a>
<span class="sourceLineNo">265</span> private static boolean preadWithExtraDirectly(ByteBuff buff, FSDataInputStream dis, long position,<a name="line.265"></a>
<span class="sourceLineNo">266</span> int necessaryLen, int extraLen) throws IOException {<a name="line.266"></a>
<span class="sourceLineNo">267</span> int remain = necessaryLen + extraLen, bytesRead = 0, idx = 0;<a name="line.267"></a>
<span class="sourceLineNo">268</span> ByteBuffer[] buffers = buff.nioByteBuffers();<a name="line.268"></a>
<span class="sourceLineNo">269</span> ByteBuffer cur = buffers[idx];<a name="line.269"></a>
<span class="sourceLineNo">270</span> while (bytesRead &lt; necessaryLen) {<a name="line.270"></a>
<span class="sourceLineNo">271</span> int ret;<a name="line.271"></a>
<span class="sourceLineNo">272</span> while (!cur.hasRemaining()) {<a name="line.272"></a>
<span class="sourceLineNo">273</span> if (++idx &gt;= buffers.length) {<a name="line.273"></a>
<span class="sourceLineNo">274</span> throw new IOException("Not enough ByteBuffers to read the reminding " + remain + "bytes");<a name="line.274"></a>
<span class="sourceLineNo">275</span> }<a name="line.275"></a>
<span class="sourceLineNo">276</span> cur = buffers[idx];<a name="line.276"></a>
<span class="sourceLineNo">277</span> }<a name="line.277"></a>
<span class="sourceLineNo">278</span> cur.limit(cur.position() + Math.min(remain, cur.remaining()));<a name="line.278"></a>
<span class="sourceLineNo">279</span> try {<a name="line.279"></a>
<span class="sourceLineNo">280</span> ret = (Integer) byteBufferPositionedReadMethod.invoke(dis, position + bytesRead, cur);<a name="line.280"></a>
<span class="sourceLineNo">281</span> } catch (IllegalAccessException e) {<a name="line.281"></a>
<span class="sourceLineNo">282</span> throw new IOException("Unable to invoke ByteBuffer positioned read when trying to read "<a name="line.282"></a>
<span class="sourceLineNo">283</span> + bytesRead + " bytes from position " + position, e);<a name="line.283"></a>
<span class="sourceLineNo">284</span> } catch (InvocationTargetException e) {<a name="line.284"></a>
<span class="sourceLineNo">285</span> throw new IOException("Encountered an exception when invoking ByteBuffer positioned read"<a name="line.285"></a>
<span class="sourceLineNo">286</span> + " when trying to read " + bytesRead + " bytes from position " + position, e);<a name="line.286"></a>
<span class="sourceLineNo">287</span> } catch (NullPointerException e) {<a name="line.287"></a>
<span class="sourceLineNo">288</span> throw new IOException("something is null");<a name="line.288"></a>
<span class="sourceLineNo">289</span> } catch (Exception e) {<a name="line.289"></a>
<span class="sourceLineNo">290</span> throw e;<a name="line.290"></a>
<span class="sourceLineNo">291</span> }<a name="line.291"></a>
<span class="sourceLineNo">292</span> if (ret &lt; 0) {<a name="line.292"></a>
<span class="sourceLineNo">293</span> throw new IOException("Premature EOF from inputStream (positional read returned " + ret<a name="line.293"></a>
<span class="sourceLineNo">294</span> + ", was trying to read " + necessaryLen + " necessary bytes and " + extraLen<a name="line.294"></a>
<span class="sourceLineNo">295</span> + " extra bytes, successfully read " + bytesRead);<a name="line.295"></a>
<span class="sourceLineNo">296</span> }<a name="line.296"></a>
<span class="sourceLineNo">297</span> bytesRead += ret;<a name="line.297"></a>
<span class="sourceLineNo">298</span> remain -= ret;<a name="line.298"></a>
<span class="sourceLineNo">299</span> }<a name="line.299"></a>
<span class="sourceLineNo">300</span><a name="line.300"></a>
<span class="sourceLineNo">301</span> return (extraLen &gt; 0) &amp;&amp; (bytesRead == necessaryLen + extraLen);<a name="line.301"></a>
<span class="sourceLineNo">302</span> }<a name="line.302"></a>
<span class="sourceLineNo">303</span><a name="line.303"></a>
<span class="sourceLineNo">304</span> private static int copyToByteBuff(byte[] buf, int offset, int len, ByteBuff out)<a name="line.304"></a>
<span class="sourceLineNo">305</span> throws IOException {<a name="line.305"></a>
<span class="sourceLineNo">306</span> if (offset &lt; 0 || len &lt; 0 || offset + len &gt; buf.length) {<a name="line.306"></a>
<span class="sourceLineNo">307</span> throw new IOException("Invalid offset=" + offset + " and len=" + len + ", cap=" + buf.length);<a name="line.307"></a>
<span class="sourceLineNo">308</span> }<a name="line.308"></a>
<span class="sourceLineNo">309</span> ByteBuffer[] buffers = out.nioByteBuffers();<a name="line.309"></a>
<span class="sourceLineNo">310</span> int idx = 0, remain = len, copyLen;<a name="line.310"></a>
<span class="sourceLineNo">311</span> ByteBuffer cur = buffers[idx];<a name="line.311"></a>
<span class="sourceLineNo">312</span> while (remain &gt; 0) {<a name="line.312"></a>
<span class="sourceLineNo">313</span> while (!cur.hasRemaining()) {<a name="line.313"></a>
<span class="sourceLineNo">314</span> if (++idx &gt;= buffers.length) {<a name="line.314"></a>
<span class="sourceLineNo">315</span> throw new IOException("Not enough ByteBuffers to read the reminding " + remain + "bytes");<a name="line.315"></a>
<span class="sourceLineNo">316</span> }<a name="line.316"></a>
<span class="sourceLineNo">317</span> cur = buffers[idx];<a name="line.317"></a>
<span class="sourceLineNo">318</span> }<a name="line.318"></a>
<span class="sourceLineNo">319</span> copyLen = Math.min(cur.remaining(), remain);<a name="line.319"></a>
<span class="sourceLineNo">320</span> cur.put(buf, offset, copyLen);<a name="line.320"></a>
<span class="sourceLineNo">321</span> remain -= copyLen;<a name="line.321"></a>
<span class="sourceLineNo">322</span> offset += copyLen;<a name="line.322"></a>
<span class="sourceLineNo">323</span> }<a name="line.323"></a>
<span class="sourceLineNo">324</span> return len;<a name="line.324"></a>
<span class="sourceLineNo">325</span> }<a name="line.325"></a>
<span class="sourceLineNo">326</span>}<a name="line.326"></a>
</pre>
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