From 576650142c498f54f935770e7fdaf38b6b6f3de2 Mon Sep 17 00:00:00 2001
From: Miron Cuperman <miron+code@google.com>
Date: Fri, 23 Mar 2012 12:53:54 -0700
Subject: [PATCH] Lock in BOBS on creation, do not swallow non-IO exceptions

---
 .../store/BoundedOverheadBlockStore.java      | 35 +++++++++++--------
 .../store/BoundedOverheadBlockStoreTest.java  | 19 ++++++++++
 2 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/core/src/main/java/com/google/bitcoin/store/BoundedOverheadBlockStore.java b/core/src/main/java/com/google/bitcoin/store/BoundedOverheadBlockStore.java
index 28f9acf3..7669ecb6 100644
--- a/core/src/main/java/com/google/bitcoin/store/BoundedOverheadBlockStore.java
+++ b/core/src/main/java/com/google/bitcoin/store/BoundedOverheadBlockStore.java
@@ -152,7 +152,7 @@ public class BoundedOverheadBlockStore implements BlockStore {
             try {
                 load(file);
                 return;
-            } catch (Exception e) {
+            } catch (IOException e) {
                 log.error("Failed to load block chain from " + file, e);
                 // Fall through and try to create a new one.
             }
@@ -172,6 +172,7 @@ public class BoundedOverheadBlockStore implements BlockStore {
             // Create fresh. The d makes writes synchronous.
             this.file = new RandomAccessFile(file, "rwd");
             this.channel = this.file.getChannel();
+            lock();
             this.file.write(FILE_FORMAT_VERSION);
         } catch (IOException e1) {
             // We could not load a block store nor could we create a new one!
@@ -195,21 +196,9 @@ public class BoundedOverheadBlockStore implements BlockStore {
         log.info("Reading block store from {}", file);
         // Open in synchronous mode. See above.
         this.file = new RandomAccessFile(file, "rwd");
+        channel = this.file.getChannel();
+        lock();
         try {
-            lock = this.file.getChannel().tryLock();
-        } catch (OverlappingFileLockException e) {
-            lock = null;
-        }
-        if (lock == null) {
-            try {
-                this.file.close();
-            } finally {
-                this.file = null;
-            }
-            throw new BlockStoreException("Could not lock file");
-        }
-        try {
-            channel = this.file.getChannel();
             // Read a version byte.
             int version = this.file.read();
             if (version == -1) {
@@ -235,6 +224,22 @@ public class BoundedOverheadBlockStore implements BlockStore {
         }
     }
 
+    private void lock() throws IOException, BlockStoreException {
+        try {
+            lock = channel.tryLock();
+        } catch (OverlappingFileLockException e) {
+            lock = null;
+        }
+        if (lock == null) {
+            try {
+                this.file.close();
+            } finally {
+                this.file = null;
+            }
+            throw new BlockStoreException("Could not lock file");
+        }
+    }
+
     private void ensureOpen() throws BlockStoreException {
         if (file == null) {
             throw new BlockStoreException("BlockStore was closed");
diff --git a/core/src/test/java/com/google/bitcoin/store/BoundedOverheadBlockStoreTest.java b/core/src/test/java/com/google/bitcoin/store/BoundedOverheadBlockStoreTest.java
index b56fcc3f..15e19065 100644
--- a/core/src/test/java/com/google/bitcoin/store/BoundedOverheadBlockStoreTest.java
+++ b/core/src/test/java/com/google/bitcoin/store/BoundedOverheadBlockStoreTest.java
@@ -24,6 +24,7 @@ import org.junit.Test;
 import java.io.File;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
 
 public class BoundedOverheadBlockStoreTest {
     @Test
@@ -43,6 +44,8 @@ public class BoundedOverheadBlockStoreTest {
         StoredBlock b1 = genesis.build(genesis.getHeader().createNextBlock(to).cloneAsHeader());
         store.put(b1);
         store.setChainHead(b1);
+        store.close();
+        
         // Check we can get it back out again if we rebuild the store object.
         store = new BoundedOverheadBlockStore(params, temp);
         StoredBlock b2 = store.get(b1.getHeader().getHash());
@@ -50,4 +53,20 @@ public class BoundedOverheadBlockStoreTest {
         // Check the chain head was stored correctly also.
         assertEquals(b1, store.getChainHead());
     }
+    
+    @Test
+    public void testLocking() throws Exception {
+        File temp = File.createTempFile("bitcoinj-test", null, null);
+        System.out.println(temp.getAbsolutePath());
+        temp.deleteOnExit();
+
+        NetworkParameters params = NetworkParameters.unitTests();
+        BoundedOverheadBlockStore store = new BoundedOverheadBlockStore(params, temp);
+        try {
+            BoundedOverheadBlockStore store1 = new BoundedOverheadBlockStore(params, temp);
+            fail();
+        } catch (BlockStoreException e) {
+            // Expected
+        }
+    }
 }