Add low-level APIs for unpacking Timestamp values (#580)

Author: xerial

msgpack-core/src/main/java/org/msgpack/core/ExtensionTypeHeader.java

@@ -59,6 +59,11 @@ public byte getType()
         return type;
     }
 
+    public boolean isTimestampType()
+    {
+        return type == MessagePack.Code.EXT_TIMESTAMP;
+    }
+
     public int getLength()
     {
         return length;

msgpack-core/src/main/java/org/msgpack/core/MessageUnpacker.java

@@ -1284,9 +1284,9 @@ public Instant unpackTimestamp()
     }
 
     /**
-     * Internal method that can be used only when the extension type header is already read.
+     * Unpack timestamp that can be used after reading the extension type header with unpackExtensionTypeHeader.
      */
-    private Instant unpackTimestamp(ExtensionTypeHeader ext) throws IOException
+    public Instant unpackTimestamp(ExtensionTypeHeader ext) throws IOException
     {
         if (ext.getType() != EXT_TIMESTAMP) {
             throw unexpectedExtension("Timestamp", EXT_TIMESTAMP, ext.getType());

msgpack-core/src/test/java/org/msgpack/core/example/MessagePackExample.java

@@ -26,13 +26,15 @@
 import org.msgpack.value.ExtensionValue;
 import org.msgpack.value.FloatValue;
 import org.msgpack.value.IntegerValue;
+import org.msgpack.value.TimestampValue;
 import org.msgpack.value.Value;
 
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.math.BigInteger;
+import java.time.Instant;
 
 /**
  * This class describes the usage of MessagePack
@@ -145,6 +147,9 @@ public static void packer()
         packer.packExtensionTypeHeader((byte) 1, 10);  // type number [0, 127], data byte length
         packer.writePayload(extData);
 
+        // Pack timestamp
+        packer.packTimestamp(Instant.now());
+
         // Succinct syntax for packing
         packer
                 .packInt(1)
@@ -228,8 +233,15 @@ else if (iv.isInLongRange()) {
                     break;
                 case EXTENSION:
                     ExtensionValue ev = v.asExtensionValue();
-                    byte extType = ev.getType();
-                    byte[] extValue = ev.getData();
+                    if (ev.isTimestampValue()) {
+                        // Reading the value as a timestamp
+                        TimestampValue ts = ev.asTimestampValue();
+                        Instant tsValue = ts.toInstant();
+                    }
+                    else {
+                        byte extType = ev.getType();
+                        byte[] extValue = ev.getData();
+                    }
                     break;
             }
         }

msgpack-core/src/test/scala/org/msgpack/core/MessagePackTest.scala

@@ -662,6 +662,24 @@ class MessagePackTest extends AirSpec with PropertyCheck with Benchmark {
     }
   }
 
+  test("pack/unpack timestamp through ExtValue") {
+    val posLong = Gen.chooseNum[Long](-31557014167219200L, 31556889864403199L)
+    forAll(posLong) { (millis: Long) =>
+      val v = Instant.ofEpochMilli(millis)
+      check(v, { _.packTimestamp(millis) },
+        { u =>
+          val extHeader = u.unpackExtensionTypeHeader()
+          if(extHeader.isTimestampType) {
+            u.unpackTimestamp(extHeader)
+          }
+          else {
+            fail("Cannot reach here")
+          }
+        }
+      )
+    }
+  }
+
   test("MessagePack.PackerConfig") {
     test("should be immutable") {
       val a = new MessagePack.PackerConfig()