blockstore: do not write block twice

lib/blockstore/file.js

@@ -297,6 +297,11 @@ class FileBlockStore extends AbstractBlockStore {
 
     this.writing = true;
 
+    if (await this.db.has(layout.b.encode(type, hash))) {
+      this.writing = false;
+      return false;
+    }
+
     const mlength = 8;
     const blength = data.length;
     const length = data.length + mlength;
@@ -352,6 +357,8 @@ class FileBlockStore extends AbstractBlockStore {
     await b.write();
 
     this.writing = false;
+
+    return true;
   }
 
   /**

test/blockstore-test.js

@@ -391,9 +391,11 @@ describe('BlockStore', function() {
       const open = fs.open;
       const close = fs.close;
       let allocate = null;
+      let has = null;
 
       beforeEach(() => {
         allocate = store.allocate;
+        has = store.db.has;
       });
 
       afterEach(() => {
@@ -402,6 +404,7 @@ describe('BlockStore', function() {
         fs.open = open;
         fs.close = close;
         store.allocate = allocate;
+        store.db.has = has;
       });
 
       it('will error if total magic bytes not written', async () => {
@@ -416,6 +419,7 @@ describe('BlockStore', function() {
             filepath: '/tmp/.bcoin/blocks/blk00020.dat'
           };
         };
+        store.db.has = () => false;
         fs.open = () => 7;
         fs.close = () => undefined;
         fs.write = () => 0;
@@ -445,6 +449,7 @@ describe('BlockStore', function() {
             filepath: '/tmp/.bcoin/blocks/blk00020.dat'
           };
         };
+        store.db.has = () => false;
         fs.open = () => 7;
         fs.close = () => undefined;
         fs.write = (fd, buffer, offset, length, position) => {
@@ -685,6 +690,21 @@ describe('BlockStore', function() {
       }
     });
 
+    it('will not duplicate a block on disk', async () => {
+      const block = random.randomBytes(128);
+      const hash = random.randomBytes(32);
+
+      const first = await store.write(hash, block);
+      assert.equal(first, true);
+      const second = await store.write(hash, block);
+      assert.equal(second, false);
+
+      const pruned = await store.prune(hash);
+      assert.equal(pruned, true);
+
+      assert.equal(await fs.exists(store.filepath(types.BLOCK, 0)), false);
+    });
+
     it('will return null if block not found', async () => {
       const hash = random.randomBytes(32);
       const block = await store.read(hash);