blockstore: add block data types with an undo type

lib/blockstore/abstract.js

@@ -51,10 +51,16 @@ class AbstractBlockStore {
   }
 
   /**
-   * This method stores block data. The action should be idempotent.
+   * This method stores block undo coin data.
-   * If the data is already stored, the behavior will be the same. Any
+   * @returns {Promise}
-   * concurrent requests to store the same data will produce the same
+   */
-   * result, and will not conflict with each other.
+
+  async writeUndo(hash, data) {
+    throw new Error('Abstract method.');
+  }
+
+  /**
+   * This method stores block data.
    * @returns {Promise}
    */
 
@@ -62,6 +68,15 @@ class AbstractBlockStore {
     throw new Error('Abstract method.');
   }
 
+  /**
+   * This method will retrieve block undo coin data.
+   * @returns {Promise}
+   */
+
+  async readUndo(hash) {
+    throw new Error('Abstract method.');
+  }
+
   /**
    * This method will retrieve block data. Smaller portions of
    * the block can be read by using the offset and size arguments.
@@ -73,9 +88,16 @@ class AbstractBlockStore {
   }
 
   /**
-   * This will free resources for storing the block data. This
+   * This will free resources for storing the block undo coin data.
-   * may not mean that the block is deleted, but that it should
+   * @returns {Promise}
-   * no longer consume any local storage resources.
+   */
+
+  async pruneUndo(hash) {
+    throw new Error('Abstract method.');
+  }
+
+  /**
+   * This will free resources for storing the block data.
    * @returns {Promise}
    */
 
@@ -83,6 +105,16 @@ class AbstractBlockStore {
     throw new Error('Abstract method.');
   }
 
+  /**
+   * This will check if a block undo coin data has been stored
+   * and is available.
+   * @returns {Promise}
+   */
+
+  async hasUndo(hash) {
+    throw new Error('Abstract method.');
+  }
+
   /**
    * This will check if a block has been stored and is available.
    * @returns {Promise}

lib/blockstore/common.js

@@ -0,0 +1,31 @@
+/*!
+ * common.js - block store constants for bcoin
+ * Copyright (c) 2019, Braydon Fuller (MIT License).
+ * https://github.com/bcoin-org/bcoin
+ */
+
+'use strict';
+
+/**
+ * @module blockstore/common
+ */
+
+/**
+ * Data types.
+ * @enum {Number}
+ */
+
+exports.types = {
+  BLOCK: 1,
+  UNDO: 2
+};
+
+/**
+ * File prefixes for data types.
+ * @enum {String}
+ */
+
+exports.prefixes = {
+  1: 'blk',
+  2: 'blu'
+};

lib/blockstore/file.js

@@ -16,6 +16,7 @@ const Block = require('../primitives/block');
 const AbstractBlockStore = require('./abstract');
 const {BlockRecord, FileRecord} = require('./records');
 const layout = require('./layout');
+const {types, prefixes} = require('./common');
 
 /**
  * File Block Store
@@ -66,7 +67,7 @@ class FileBlockStore extends AbstractBlockStore {
     let missing = false;
 
     for (const fileno of filenos) {
-      const rec = await this.db.get(layout.f.encode(fileno));
+      const rec = await this.db.get(layout.f.encode(types.BLOCK, fileno));
       if (!rec) {
         missing = true;
         break;
@@ -80,7 +81,7 @@ class FileBlockStore extends AbstractBlockStore {
 
     for (const fileno of filenos) {
       const b = this.db.batch();
-      const filepath = this.filepath(fileno);
+      const filepath = this.filepath(types.BLOCK, fileno);
       const data = await fs.readFile(filepath);
       const reader = bio.read(data);
       let magic = null;
@@ -106,7 +107,7 @@ class FileBlockStore extends AbstractBlockStore {
         });
 
         blocks += 1;
-        b.put(layout.b.encode(hash), blockrecord.toRaw());
+        b.put(layout.b.encode(types.BLOCK, hash), blockrecord.toRaw());
       }
 
       const filerecord = new FileRecord({
@@ -115,7 +116,7 @@ class FileBlockStore extends AbstractBlockStore {
         length: this.maxFileLength
       });
 
-      b.put(layout.f.encode(fileno), filerecord.toRaw());
+      b.put(layout.f.encode(types.BLOCK, fileno), filerecord.toRaw());
 
       await b.write();
 
@@ -152,11 +153,12 @@ class FileBlockStore extends AbstractBlockStore {
   /**
    * This method will determine the file path based on the file number
    * and the current block data location.
+   * @private
    * @param {Number} fileno - The number of the file.
    * @returns {Promise}
    */
 
-  filepath(fileno) {
+  filepath(type, fileno) {
     const pad = 5;
 
     let num = fileno.toString(10);
@@ -167,17 +169,27 @@ class FileBlockStore extends AbstractBlockStore {
     while (num.length < pad)
       num = `0${num}`;
 
-    return join(this.location, `blk${num}.dat`);
+    let filepath = null;
+
+    const prefix = prefixes[type];
+
+    if (!prefix)
+      throw new Error('Unknown file prefix.');
+
+    filepath = join(this.location, `${prefix}${num}.dat`);
+
+    return filepath;
   }
 
   /**
    * This method will select and potentially allocate a file to
    * write a block based on the size.
+   * @private
    * @param {Number} length - The number of bytes of the data to be written.
    * @returns {Promise}
    */
 
-  async allocate(length) {
+  async allocate(type, length) {
     if (length > this.maxFileLength)
       throw new Error('Block length above max file length.');
 
@@ -185,13 +197,13 @@ class FileBlockStore extends AbstractBlockStore {
     let filerecord = null;
     let filepath = null;
 
-    const last = await this.db.get(layout.R.encode());
+    const last = await this.db.get(layout.F.encode(type));
     if (last)
       fileno = bio.read(last).readU32();
 
-    filepath = this.filepath(fileno);
+    filepath = this.filepath(type, fileno);
 
-    const rec = await this.db.get(layout.f.encode(fileno));
+    const rec = await this.db.get(layout.f.encode(type, fileno));
 
     let touch = false;
 
@@ -208,7 +220,7 @@ class FileBlockStore extends AbstractBlockStore {
 
     if (filerecord.used + length > filerecord.length) {
       fileno += 1;
-      filepath = this.filepath(fileno);
+      filepath = this.filepath(type, fileno);
       touch = true;
       filerecord = new FileRecord({
         blocks: 0,
@@ -225,6 +237,17 @@ class FileBlockStore extends AbstractBlockStore {
     return {fileno, filerecord, filepath};
   }
 
+  /**
+   * This method stores block undo coin data in files.
+   * @param {Buffer} hash - The block hash
+   * @param {Buffer} data - The block data
+   * @returns {Promise}
+   */
+
+  async writeUndo(hash, data) {
+    return this._write(types.UNDO, hash, data);
+  }
+
   /**
    * This method stores block data in files.
    * @param {Buffer} hash - The block hash
@@ -233,6 +256,20 @@ class FileBlockStore extends AbstractBlockStore {
    */
 
   async write(hash, data) {
+    return this._write(types.BLOCK, hash, data);
+  }
+
+  /**
+   * This method stores block data in files with by appending
+   * data to the last written file and updating indexes to point
+   * to the file and position.
+   * @private
+   * @param {Buffer} hash - The block hash
+   * @param {Buffer} data - The block data
+   * @returns {Promise}
+   */
+
+  async _write(type, hash, data) {
     if (this.writing)
       throw new Error('Already writing.');
 
@@ -246,7 +283,7 @@ class FileBlockStore extends AbstractBlockStore {
       fileno,
       filerecord,
       filepath
-    } = await this.allocate(length);
+    } = await this.allocate(type, length);
 
     const mposition = filerecord.used;
     const bposition = filerecord.used + mlength;
@@ -280,17 +317,27 @@ class FileBlockStore extends AbstractBlockStore {
       length: blength
     });
 
-    b.put(layout.b.encode(hash), blockrecord.toRaw());
+    b.put(layout.b.encode(type, hash), blockrecord.toRaw());
-    b.put(layout.f.encode(fileno), filerecord.toRaw());
+    b.put(layout.f.encode(type, fileno), filerecord.toRaw());
 
-    const bw = bio.write(4);
+    const last = bio.write(4).writeU32(fileno).render();
-    b.put(layout.R.encode(), bw.writeU32(fileno).render());
+    b.put(layout.F.encode(type), last);
 
     await b.write();
 
     this.writing = false;
   }
 
+  /**
+   * This method will retrieve block undo coin data.
+   * @param {Buffer} hash - The block hash
+   * @returns {Promise}
+   */
+
+  async readUndo(hash) {
+    return this._read(types.UNDO, hash);
+  }
+
   /**
    * This method will retrieve block data. Smaller portions of the
    * block (e.g. transactions) can be read by using the offset and
@@ -302,13 +349,28 @@ class FileBlockStore extends AbstractBlockStore {
    */
 
   async read(hash, offset, length) {
-    const raw = await this.db.get(layout.b.encode(hash));
+    return this._read(types.BLOCK, hash, offset, length);
+  }
+
+  /**
+   * This methods reads data from disk by retrieving the index of
+   * the data and reading from the correponding file and location.
+   * @private
+   * @param {Buffer} type - The data type
+   * @param {Buffer} hash - The block hash
+   * @param {Number} offset - The offset within the block
+   * @param {Number} length - The number of bytes of the data
+   * @returns {Promise}
+   */
+
+  async _read(type, hash, offset, length) {
+    const raw = await this.db.get(layout.b.encode(type, hash));
     if (!raw)
       return null;
 
     const blockrecord = BlockRecord.fromRaw(raw);
 
-    const filepath = this.filepath(blockrecord.file);
+    const filepath = this.filepath(type, blockrecord.file);
 
     let position = blockrecord.position;
 
@@ -331,22 +393,43 @@ class FileBlockStore extends AbstractBlockStore {
   }
 
   /**
-   * This will free resources for storing the block data. The block
+   * This will free resources for storing the block undo coin data.
-   * data may not be deleted from disk immediately, the index for
+   * @param {Buffer} hash - The block hash
-   * the block is removed and will not be able to be read. The underlying
+   * @returns {Promise}
-   * file is unlinked when all blocks in a file have been pruned.
+   */
+
+  async pruneUndo(hash) {
+    return this._prune(types.UNDO, hash);
+  }
+
+  /**
+   * This will free resources for storing the block data.
    * @param {Buffer} hash - The block hash
    * @returns {Promise}
    */
 
   async prune(hash) {
-    const braw = await this.db.get(layout.b.encode(hash));
+    return this._prune(types.BLOCK, hash);
+  }
+
+  /**
+   * This will free resources for storing the block data. The block
+   * data may not be deleted from disk immediately, the index for the
+   * block is removed and will not be able to be read. The underlying
+   * file is unlinked when all blocks in a file have been pruned.
+   * @private
+   * @param {Buffer} hash - The block hash
+   * @returns {Promise}
+   */
+
+  async _prune(type, hash) {
+    const braw = await this.db.get(layout.b.encode(type, hash));
     if (!braw)
       return false;
 
     const blockrecord = BlockRecord.fromRaw(braw);
 
-    const fraw = await this.db.get(layout.f.encode(blockrecord.file));
+    const fraw = await this.db.get(layout.f.encode(type, blockrecord.file));
     if (!fraw)
       return false;
 
@@ -357,20 +440,31 @@ class FileBlockStore extends AbstractBlockStore {
     const b = this.db.batch();
 
     if (filerecord.blocks === 0)
-      b.del(layout.f.encode(blockrecord.file));
+      b.del(layout.f.encode(type, blockrecord.file));
     else
-      b.put(layout.f.encode(blockrecord.file), filerecord.toRaw());
+      b.put(layout.f.encode(type, blockrecord.file), filerecord.toRaw());
 
-    b.del(layout.b.encode(hash));
+    b.del(layout.b.encode(type, hash));
 
     await b.write();
 
     if (filerecord.blocks === 0)
-      await fs.unlink(this.filepath(blockrecord.file));
+      await fs.unlink(this.filepath(type, blockrecord.file));
 
     return true;
   }
 
+  /**
+   * This will check if a block undo coin has been stored
+   * and is available.
+   * @param {Buffer} hash - The block hash
+   * @returns {Promise}
+   */
+
+  async hasUndo(hash) {
+    return await this.db.has(layout.b.encode(types.UNDO, hash));
+  }
+
   /**
    * This will check if a block has been stored and is available.
    * @param {Buffer} hash - The block hash
@@ -378,7 +472,7 @@ class FileBlockStore extends AbstractBlockStore {
    */
 
   async has(hash) {
-    return await this.db.has(layout.b.encode(hash));
+    return await this.db.has(layout.b.encode(types.BLOCK, hash));
   }
 }
 

lib/blockstore/layout.js

@@ -11,16 +11,16 @@ const bdb = require('bdb');
 /*
  * Database Layout:
  *   V -> db version
- *   R -> last file entry
+ *   B[type] -> last file record by type
- *   f[uint32] -> file entry
+ *   f[type][fileno] -> file record by type and file number
- *   b[hash] -> block entry
+ *   b[type][hash] -> block record by type and block hash
  */
 
 const layout = {
   V: bdb.key('V'),
-  R: bdb.key('R'),
+  F: bdb.key('F', ['uint32']),
-  f: bdb.key('f', ['uint32']),
+  f: bdb.key('f', ['uint32', 'uint32']),
-  b: bdb.key('b', ['hash256'])
+  b: bdb.key('b', ['uint32', 'hash256'])
 };
 
 /*

lib/blockstore/level.js

@@ -11,6 +11,7 @@ const bdb = require('bdb');
 const assert = require('bsert');
 const AbstractBlockStore = require('./abstract');
 const layout = require('./layout');
+const {types} = require('./common');
 
 /**
  * LevelDB Block Store
@@ -58,6 +59,17 @@ class LevelBlockStore extends AbstractBlockStore {
     await this.db.close();
   }
 
+  /**
+   * This method stores block undo coin data in LevelDB.
+   * @param {Buffer} hash - The block hash
+   * @param {Buffer} data - The block data
+   * @returns {Promise}
+   */
+
+  async writeUndo(hash, data) {
+    return this.db.put(layout.b.encode(types.UNDO, hash), data);
+  }
+
   /**
    * This method stores block data in LevelDB.
    * @param {Buffer} hash - The block hash
@@ -66,7 +78,17 @@ class LevelBlockStore extends AbstractBlockStore {
    */
 
   async write(hash, data) {
-    return this.db.put(layout.b.encode(hash), data);
+    return this.db.put(layout.b.encode(types.BLOCK, hash), data);
+  }
+
+  /**
+   * This method will retrieve block undo coin data.
+   * @param {Buffer} hash - The block hash
+   * @returns {Promise}
+   */
+
+  async readUndo(hash) {
+    return this.db.get(layout.b.encode(types.UNDO, hash));
   }
 
   /**
@@ -81,7 +103,7 @@ class LevelBlockStore extends AbstractBlockStore {
    */
 
   async read(hash, offset, length) {
-    let raw = await this.db.get(layout.b.encode(hash));
+    let raw = await this.db.get(layout.b.encode(types.BLOCK, hash));
 
     if (offset) {
       if (offset + length > raw.length)
@@ -93,6 +115,23 @@ class LevelBlockStore extends AbstractBlockStore {
     return raw;
   }
 
+  /**
+   * This will free resources for storing the block undo coin data.
+   * The block data may not be immediately removed from disk, and will
+   * be reclaimed during LevelDB compaction.
+   * @param {Buffer} hash - The block hash
+   * @returns {Promise}
+   */
+
+  async pruneUndo(hash) {
+    if (!await this.hasUndo(hash))
+      return false;
+
+    await this.db.del(layout.b.encode(types.UNDO, hash));
+
+    return true;
+  }
+
   /**
    * This will free resources for storing the block data. The block
    * data may not be immediately removed from disk, and will be reclaimed
@@ -105,11 +144,22 @@ class LevelBlockStore extends AbstractBlockStore {
     if (!await this.has(hash))
       return false;
 
-    await this.db.del(layout.b.encode(hash));
+    await this.db.del(layout.b.encode(types.BLOCK, hash));
 
     return true;
   }
 
+  /**
+   * This will check if a block undo coin data has been stored
+   * and is available.
+   * @param {Buffer} hash - The block hash
+   * @returns {Promise}
+   */
+
+  async hasUndo(hash) {
+    return this.db.has(layout.b.encode(types.UNDO, hash));
+  }
+
   /**
    * This will check if a block has been stored and is available.
    * @param {Buffer} hash - The block hash
@@ -117,7 +167,7 @@ class LevelBlockStore extends AbstractBlockStore {
    */
 
   async has(hash) {
-    return this.db.has(layout.b.encode(hash));
+    return this.db.has(layout.b.encode(types.BLOCK, hash));
   }
 }
 

test/blockstore-test.js

@@ -26,6 +26,7 @@ const {
 } = require('../lib/blockstore');
 
 const layout = require('../lib/blockstore/layout');
+const {types} = require('../lib/blockstore/common');
 
 const {
   BlockRecord,
@@ -281,7 +282,7 @@ describe('BlockStore', function() {
       it('will fail with length above file max', async () => {
         let err = null;
         try {
-          await store.allocate(1025);
+          await store.allocate(types.BLOCK, 1025);
         } catch (e) {
           err = e;
         }
@@ -292,39 +293,39 @@ describe('BlockStore', function() {
 
     describe('filepath', function() {
       it('will give correct path (0)', () => {
-        const filepath = store.filepath(0);
+        const filepath = store.filepath(types.BLOCK, 0);
         assert.equal(filepath, '/tmp/.bcoin/blocks/blk00000.dat');
       });
 
       it('will give correct path (1)', () => {
-        const filepath = store.filepath(7);
+        const filepath = store.filepath(types.BLOCK, 7);
         assert.equal(filepath, '/tmp/.bcoin/blocks/blk00007.dat');
       });
 
       it('will give correct path (2)', () => {
-        const filepath = store.filepath(23);
+        const filepath = store.filepath(types.BLOCK, 23);
         assert.equal(filepath, '/tmp/.bcoin/blocks/blk00023.dat');
       });
 
       it('will give correct path (3)', () => {
-        const filepath = store.filepath(456);
+        const filepath = store.filepath(types.BLOCK, 456);
         assert.equal(filepath, '/tmp/.bcoin/blocks/blk00456.dat');
       });
 
       it('will give correct path (4)', () => {
-        const filepath = store.filepath(8999);
+        const filepath = store.filepath(types.BLOCK, 8999);
         assert.equal(filepath, '/tmp/.bcoin/blocks/blk08999.dat');
       });
 
       it('will give correct path (5)', () => {
-        const filepath = store.filepath(99999);
+        const filepath = store.filepath(types.BLOCK, 99999);
         assert.equal(filepath, '/tmp/.bcoin/blocks/blk99999.dat');
       });
 
       it('will fail over max size', () => {
         let err = null;
         try {
-          store.filepath(100000);
+          store.filepath(types.BLOCK, 100000);
         } catch (e) {
           err = e;
         }
@@ -332,6 +333,11 @@ describe('BlockStore', function() {
         assert(err);
         assert.equal(err.message, 'File number too large.');
       });
+
+      it('will give undo type', () => {
+        const filepath = store.filepath(types.UNDO, 99999);
+        assert.equal(filepath, '/tmp/.bcoin/blocks/blu99999.dat');
+      });
     });
   });
 
@@ -366,6 +372,17 @@ describe('BlockStore', function() {
       assert.bufferEqual(block1, block2);
     });
 
+    it('will write and read block undo coins', async () => {
+      const block1 = random.randomBytes(128);
+      const hash = random.randomBytes(32);
+
+      await store.writeUndo(hash, block1);
+
+      const block2 = await store.readUndo(hash);
+
+      assert.bufferEqual(block1, block2);
+    });
+
     it('will read a block w/ offset and length', async () => {
       const block1 = random.randomBytes(128);
       const hash = random.randomBytes(32);
@@ -412,9 +429,9 @@ describe('BlockStore', function() {
         assert.bufferEqual(block2, block);
       }
 
-      const first = await fs.stat(store.filepath(0));
+      const first = await fs.stat(store.filepath(types.BLOCK, 0));
-      const second = await fs.stat(store.filepath(1));
+      const second = await fs.stat(store.filepath(types.BLOCK, 1));
-      const third = await fs.stat(store.filepath(2));
+      const third = await fs.stat(store.filepath(types.BLOCK, 2));
       assert.equal(first.size, 952);
       assert.equal(second.size, 952);
       assert.equal(third.size, 272);
@@ -429,6 +446,35 @@ describe('BlockStore', function() {
       }
     });
 
+    it('will allocate new files with block undo coins', async () => {
+      const blocks = [];
+
+      for (let i = 0; i < 16; i++) {
+        const block = random.randomBytes(128);
+        const hash = random.randomBytes(32);
+        blocks.push({hash, block});
+        await store.writeUndo(hash, block);
+        const block2 = await store.readUndo(hash);
+        assert.bufferEqual(block2, block);
+      }
+
+      const first = await fs.stat(store.filepath(types.UNDO, 0));
+      const second = await fs.stat(store.filepath(types.UNDO, 1));
+      const third = await fs.stat(store.filepath(types.UNDO, 2));
+      assert.equal(first.size, 952);
+      assert.equal(second.size, 952);
+      assert.equal(third.size, 272);
+
+      const len = first.size + second.size + third.size - (8 * 16);
+      assert.equal(len, 128 * 16);
+
+      for (let i = 0; i < 16; i++) {
+        const expect = blocks[i];
+        const block = await store.readUndo(expect.hash);
+        assert.bufferEqual(block, expect.block);
+      }
+    });
+
     it('will recover from interrupt during block write', async () => {
       {
         const block = random.randomBytes(128);
@@ -445,7 +491,7 @@ describe('BlockStore', function() {
       // would not be updated to include the used bytes and
       // thus this data should be overwritten.
       {
-        const filepath = store.filepath(0);
+        const filepath = store.filepath(types.BLOCK, 0);
 
         const fd = await fs.open(filepath, 'a');
 
@@ -522,6 +568,20 @@ describe('BlockStore', function() {
       assert.strictEqual(exists, true);
     });
 
+    it('will check if block undo coins exists (false)', async () => {
+      const hash = random.randomBytes(32);
+      const exists = await store.hasUndo(hash);
+      assert.strictEqual(exists, false);
+    });
+
+    it('will check if block undo coins exists (true)', async () => {
+      const block = random.randomBytes(128);
+      const hash = random.randomBytes(32);
+      await store.writeUndo(hash, block);
+      const exists = await store.hasUndo(hash);
+      assert.strictEqual(exists, true);
+    });
+
     it('will prune blocks', async () => {
       const hashes = [];
       for (let i = 0; i < 16; i++) {
@@ -531,9 +591,9 @@ describe('BlockStore', function() {
         await store.write(hash, block);
       }
 
-      const first = await fs.stat(store.filepath(0));
+      const first = await fs.stat(store.filepath(types.BLOCK, 0));
-      const second = await fs.stat(store.filepath(1));
+      const second = await fs.stat(store.filepath(types.BLOCK, 1));
-      const third = await fs.stat(store.filepath(2));
+      const third = await fs.stat(store.filepath(types.BLOCK, 2));
 
       const len = first.size + second.size + third.size - (8 * 16);
       assert.equal(len, 128 * 16);
@@ -543,16 +603,50 @@ describe('BlockStore', function() {
         assert.strictEqual(pruned, true);
       }
 
-      assert.equal(await fs.exists(store.filepath(0)), false);
+      assert.equal(await fs.exists(store.filepath(types.BLOCK, 0)), false);
-      assert.equal(await fs.exists(store.filepath(1)), false);
+      assert.equal(await fs.exists(store.filepath(types.BLOCK, 1)), false);
-      assert.equal(await fs.exists(store.filepath(2)), false);
+      assert.equal(await fs.exists(store.filepath(types.BLOCK, 2)), false);
 
       for (let i = 0; i < 16; i++) {
         const exists = await store.has(hashes[i]);
         assert.strictEqual(exists, false);
       }
 
-      const exists = await store.db.has(layout.f.encode(0));
+      const exists = await store.db.has(layout.f.encode(types.BLOCK, 0));
+      assert.strictEqual(exists, false);
+    });
+
+    it('will prune block undo coins', async () => {
+      const hashes = [];
+      for (let i = 0; i < 16; i++) {
+        const block = random.randomBytes(128);
+        const hash = random.randomBytes(32);
+        hashes.push(hash);
+        await store.writeUndo(hash, block);
+      }
+
+      const first = await fs.stat(store.filepath(types.UNDO, 0));
+      const second = await fs.stat(store.filepath(types.UNDO, 1));
+      const third = await fs.stat(store.filepath(types.UNDO, 2));
+
+      const len = first.size + second.size + third.size - (8 * 16);
+      assert.equal(len, 128 * 16);
+
+      for (let i = 0; i < 16; i++) {
+        const pruned = await store.pruneUndo(hashes[i]);
+        assert.strictEqual(pruned, true);
+      }
+
+      assert.equal(await fs.exists(store.filepath(types.UNDO, 0)), false);
+      assert.equal(await fs.exists(store.filepath(types.UNDO, 1)), false);
+      assert.equal(await fs.exists(store.filepath(types.UNDO, 2)), false);
+
+      for (let i = 0; i < 16; i++) {
+        const exists = await store.hasUndo(hashes[i]);
+        assert.strictEqual(exists, false);
+      }
+
+      const exists = await store.db.has(layout.f.encode(types.UNDO, 0));
       assert.strictEqual(exists, false);
     });
   });
@@ -639,6 +733,17 @@ describe('BlockStore', function() {
       assert.bufferEqual(block1, block2);
     });
 
+    it('will write and read block undo coins', async () => {
+      const block1 = random.randomBytes(128);
+      const hash = random.randomBytes(32);
+
+      await store.writeUndo(hash, block1);
+
+      const block2 = await store.readUndo(hash);
+
+      assert.bufferEqual(block1, block2);
+    });
+
     it('will read a block w/ offset and length', async () => {
       const block1 = random.randomBytes(128);
       const hash = random.randomBytes(32);
@@ -687,6 +792,20 @@ describe('BlockStore', function() {
       assert.strictEqual(exists, true);
     });
 
+    it('will check if block undo coins exists (false)', async () => {
+      const hash = random.randomBytes(32);
+      const exists = await store.has(hash);
+      assert.strictEqual(exists, false);
+    });
+
+    it('will check if block undo coins exists (true)', async () => {
+      const block = random.randomBytes(128);
+      const hash = random.randomBytes(32);
+      await store.writeUndo(hash, block);
+      const exists = await store.hasUndo(hash);
+      assert.strictEqual(exists, true);
+    });
+
     it('will prune blocks (true)', async () => {
       const block = random.randomBytes(128);
       const hash = random.randomBytes(32);
@@ -704,5 +823,23 @@ describe('BlockStore', function() {
       const pruned = await store.prune(hash);
       assert.strictEqual(pruned, false);
     });
+
+    it('will prune block undo coins (true)', async () => {
+      const block = random.randomBytes(128);
+      const hash = random.randomBytes(32);
+      await store.writeUndo(hash, block);
+      const pruned = await store.pruneUndo(hash);
+      assert.strictEqual(pruned, true);
+      const block2 = await store.readUndo(hash);
+      assert.strictEqual(block2, null);
+    });
+
+    it('will prune block undo coins (false)', async () => {
+      const hash = random.randomBytes(32);
+      const exists = await store.hasUndo(hash);
+      assert.strictEqual(exists, false);
+      const pruned = await store.pruneUndo(hash);
+      assert.strictEqual(pruned, false);
+    });
   });
 });