HDDS-732. Add read method which takes offset and length in SignedChunkInputStream. Contributed by chencan.

hadoop-ozone/s3gateway/src/main/java/org/apache/hadoop/ozone/s3/SignedChunksInputStream.java

@@ -65,6 +65,46 @@ public class SignedChunksInputStream extends InputStream {
     }
   }
 
+  @Override
+  public int read(byte b[], int off, int len) throws IOException {
+    if (b == null) {
+      throw new NullPointerException();
+    } else if (off < 0 || len < 0 || len > b.length - off) {
+      throw new IndexOutOfBoundsException();
+    } else if (len == 0) {
+      return 0;
+    }
+    int currentOff = off;
+    int currentLen = len;
+    int totalReadBytes = 0;
+    int realReadLen = 0;
+    int maxReadLen = 0;
+    do {
+      if (remainingData > 0) {
+        maxReadLen = Math.min(remainingData, currentLen);
+        realReadLen = originalStream.read(b, currentOff, maxReadLen);
+        if (realReadLen == -1) {
+          break;
+        }
+        currentOff += realReadLen;
+        currentLen -= realReadLen;
+        totalReadBytes += realReadLen;
+        remainingData -= realReadLen;
+        if (remainingData == 0) {
+          //read the "\r\n" at the end of the data section
+          originalStream.read();
+          originalStream.read();
+        }
+      } else {
+        remainingData = readHeader();
+        if (remainingData == -1) {
+          break;
+        }
+      }
+    } while (currentLen > 0);
+    return totalReadBytes > 0 ? totalReadBytes : -1;
+  }
+
   private int readHeader() throws IOException {
     int prev = -1;
     int curr = 0;

hadoop-ozone/s3gateway/src/test/java/org/apache/hadoop/ozone/s3/TestSignedChunksInputStream.java

@@ -49,32 +49,62 @@ public class TestSignedChunksInputStream {
 
   @Test
   public void singlechunk() throws IOException {
+    //test simple read()
     InputStream is = fileContent("0A;chunk-signature"
         +
         "=23abb2bd920ddeeaac78a63ed808bc59fa6e7d3ef0e356474b82cdc2f8c93c40\r"
         + "\n1234567890\r\n");
     String result = IOUtils.toString(is, Charset.forName("UTF-8"));
     Assert.assertEquals("1234567890", result);
+
+    //test read(byte[],int,int)
+    is = fileContent("0A;chunk-signature"
+        +
+        "=23abb2bd920ddeeaac78a63ed808bc59fa6e7d3ef0e356474b82cdc2f8c93c40\r"
+        + "\n1234567890\r\n");
+    byte[] bytes = new byte[10];
+    IOUtils.read(is, bytes, 0, 10);
+    Assert.assertEquals("1234567890", new String(bytes));
   }
 
   @Test
   public void singlechunkwithoutend() throws IOException {
+    //test simple read()
     InputStream is = fileContent("0A;chunk-signature"
         +
         "=23abb2bd920ddeeaac78a63ed808bc59fa6e7d3ef0e356474b82cdc2f8c93c40\r"
         + "\n1234567890");
     String result = IOUtils.toString(is, Charset.forName("UTF-8"));
     Assert.assertEquals("1234567890", result);
+
+    //test read(byte[],int,int)
+    is = fileContent("0A;chunk-signature"
+        +
+        "=23abb2bd920ddeeaac78a63ed808bc59fa6e7d3ef0e356474b82cdc2f8c93c40\r"
+        + "\n1234567890");
+    byte[] bytes = new byte[10];
+    IOUtils.read(is, bytes, 0, 10);
+    Assert.assertEquals("1234567890", new String(bytes));
   }
 
   @Test
   public void multichunks() throws IOException {
+    //test simple read()
     InputStream is = fileContent("0a;chunk-signature=signature\r\n"
         + "1234567890\r\n"
         + "05;chunk-signature=signature\r\n"
         + "abcde\r\n");
     String result = IOUtils.toString(is, Charset.forName("UTF-8"));
     Assert.assertEquals("1234567890abcde", result);
+
+    //test read(byte[],int,int)
+    is = fileContent("0a;chunk-signature=signature\r\n"
+        + "1234567890\r\n"
+        + "05;chunk-signature=signature\r\n"
+        + "abcde\r\n");
+    byte[] bytes = new byte[15];
+    IOUtils.read(is, bytes, 0, 15);
+    Assert.assertEquals("1234567890abcde", new String(bytes));
   }
 
   private InputStream fileContent(String content) {