From 3c6d02ecdd387562a2c1e5e76936dea2ad6c9a82 Mon Sep 17 00:00:00 2001
From: David Renshaw <dwrenshaw@gmail.com>
Date: Thu, 4 Sep 2014 15:25:56 -0400
Subject: [PATCH] add some null checks

---
 .../java/org/capnproto/PointerReader.java     | 26 +++++++++++++------
 .../java/org/capnproto/SegmentReader.java     |  2 ++
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/runtime/src/main/java/org/capnproto/PointerReader.java b/runtime/src/main/java/org/capnproto/PointerReader.java
index 0e0bc78..fbaef62 100644
--- a/runtime/src/main/java/org/capnproto/PointerReader.java
+++ b/runtime/src/main/java/org/capnproto/PointerReader.java
@@ -29,17 +29,27 @@ public final class PointerReader {
     }
 
     public StructReader getStruct() {
-        return WireHelpers.readStructPointer(this.segment,
-                                             this.pointer,
-                                             this.nestingLimit);
+        if (this.segment == null) {
+            return WireHelpers.readStructPointer(SegmentReader.EMPTY, 0, this.nestingLimit);
+        } else {
+            return WireHelpers.readStructPointer(this.segment,
+                                                 this.pointer,
+                                                 this.nestingLimit);
+        }
     }
 
     public ListReader getList(byte expectedElementSize) {
-        // TODO check nullness
-        return WireHelpers.readListPointer(this.segment,
-                                           this.pointer,
-                                           expectedElementSize,
-                                           this.nestingLimit);
+        if (this.segment == null) {
+            return WireHelpers.readListPointer(SegmentReader.EMPTY,
+                                               0,
+                                               expectedElementSize,
+                                               this.nestingLimit);
+        } else {
+            return WireHelpers.readListPointer(this.segment,
+                                               this.pointer,
+                                               expectedElementSize,
+                                               this.nestingLimit);
+        }
     }
 
     public Text.Reader getText() {
diff --git a/runtime/src/main/java/org/capnproto/SegmentReader.java b/runtime/src/main/java/org/capnproto/SegmentReader.java
index 7a59e2e..0ffb294 100644
--- a/runtime/src/main/java/org/capnproto/SegmentReader.java
+++ b/runtime/src/main/java/org/capnproto/SegmentReader.java
@@ -13,4 +13,6 @@ public class SegmentReader {
         this.buffer = buffer;
         this.arena = arena;
     }
+
+    public static final SegmentReader EMPTY = new SegmentReader(ByteBuffer.allocate(8), null);
 }