Fix for Issue #1576 to fetch data correctly when a chunk spans multiple packets

Author: sharadraju

doc/src/release_notes.rst

@@ -11,6 +11,9 @@ node-oracledb `v6.0.2 <https://github.com/oracle/node-oracledb/compare/v6.0.1...
 Thin Mode Changes
 +++++++++++++++++
 
+#)  Fixed bug when the length of a chunk inside a chunked read spans packets.
+    `Issue #1576 <https://github.com/oracle/node-oracledb/issues/1576>`__.
+
 #)  Fixed bug when fetching rows containing data duplicated from a previous
     row that spans multiple network packets.
     `Issue #1566 <https://github.com/oracle/node-oracledb/issues/1566>`__ and

lib/thin/protocol/packet.js

@@ -220,12 +220,17 @@ class ReadPacket extends BaseBuffer {
     }
 
     // the requested bytes are split across multiple packets; if a chunked read
-    // is not in progress one is implicitly started; copy the bytes from the
-    // end of this packet
-    if (!inChunkedRead) {
-      this.chunkedBytesBuf.startChunkedRead();
+    // is in progress, a chunk is acquired that will accommodate the requested
+    // bytes; otherwise, a separate buffer will be allocated to accommodate the
+    // requested bytes
+    let buf;
+    if (inChunkedRead) {
+      buf = this.chunkedBytesBuf.getBuf(numBytes);
+    } else {
+      buf = Buffer.alloc(numBytes);
     }
-    const buf = this.chunkedBytesBuf.getBuf(numBytes);
+
+    // copy the bytes to the buffer from the remainder of this packet
     let offset = 0;
     this.buf.copy(buf, offset, this.pos, this.pos + numBytesLeft);
     offset += numBytesLeft;
@@ -241,10 +246,7 @@ class ReadPacket extends BaseBuffer {
       numBytes -= numSplitBytes;
     }
 
-    // if not in a chunked bytes read, return the buffer directly
-    if (!inChunkedRead) {
-      return this.chunkedBytesBuf.endChunkedRead();
-    }
+    return buf;
 
   }