DAA: Fix EDA when using checkpoints.

machine-creek · Mar 22, 2018 · 95713f4 · 95713f4
1 parent 1c1f488
commit 95713f4
Showing 1 changed file with 7 additions and 0 deletions.
diff --git a/core/src/main/java/org/bitcoinj/params/AbstractBitcoinNetParams.java b/core/src/main/java/org/bitcoinj/params/AbstractBitcoinNetParams.java
@@ -95,6 +95,13 @@ public void checkDifficultyTransitions(final StoredBlock storedPrev, final Block
             }
             long mpt6blocks = 0;
             try {
+                //Check to see if there are enough blocks before cursor to correctly calculate the median time
+                StoredBlock beforeCursor = cursor;
+                for (int i = 0; i < 10; i++) {
+                    beforeCursor = blockStore.get(beforeCursor.getHeader().getPrevBlockHash());
+                    if(beforeCursor == null)
+                        return; //Not enough blocks to check difficulty.
+                }
                 mpt6blocks = blockChain.getMedianTimestampOfRecentBlocks(storedPrev, blockStore) - blockChain.getMedianTimestampOfRecentBlocks(cursor, blockStore);
             } catch (NullPointerException x)
             {