From fae647b9e97b2e31e2eb667ab927d7a55450644e Mon Sep 17 00:00:00 2001
From: Braydon Fuller <courier@braydon.com>
Date: Wed, 17 Apr 2019 17:18:07 -0700
Subject: [PATCH] indexer: simplify block meta and remove records

---
 lib/indexer/indexer.js |  29 +++++---
 lib/indexer/layout.js  |   9 +--
 lib/indexer/records.js | 152 -----------------------------------------
 3 files changed, 24 insertions(+), 166 deletions(-)
 delete mode 100644 lib/indexer/records.js

diff --git a/lib/indexer/indexer.js b/lib/indexer/indexer.js
index 702d5a4a..7c092cf2 100644
--- a/lib/indexer/indexer.js
+++ b/lib/indexer/indexer.js
@@ -15,7 +15,7 @@ const Logger = require('blgr');
 const Network = require('../protocol/network');
 const util = require('../utils/util');
 const layout = require('./layout');
-const {BlockMeta} = require('./records');
+const {ZERO_HASH} = require('../protocol/consensus');
 
 /**
  * Indexer
@@ -221,11 +221,7 @@ class Indexer extends EventEmitter {
     if (!data)
       return null;
 
-    const block = new BlockMeta();
-    block.hash = data;
-    block.height = height;
-
-    return block;
+    return new BlockMeta(data, height);
   }
 
   /**
@@ -399,7 +395,7 @@ class Indexer extends EventEmitter {
     if (entry.height !== this.height + 1)
       throw new Error('Indexer: Can not add block.');
 
-    const tip = BlockMeta.fromEntry(entry);
+    const tip = new BlockMeta(entry.hash, entry.height);
 
     // Start the batch write.
     this.start();
@@ -458,7 +454,7 @@ class Indexer extends EventEmitter {
     if (entry.height !== this.height)
       throw new Error('Indexer: Can not remove block.');
 
-    const tip = BlockMeta.fromEntry(entry);
+    const tip = new BlockMeta(entry.hash, entry.height);
 
     // Start the batch write.
     this.start();
@@ -498,7 +494,7 @@ class Indexer extends EventEmitter {
     }
 
     // Add to batch write to save tip and height.
-    this.put(layout.h.encode(tip.height), tip.toHash());
+    this.put(layout.h.encode(tip.height), tip.hash);
 
     const raw = bio.write(4).writeU32(tip.height).render();
     this.put(layout.R.encode(), raw);
@@ -544,9 +540,22 @@ class Indexer extends EventEmitter {
   }
 }
 
+/**
+ * Block Meta
+ */
+
+class BlockMeta {
+  constructor(hash, height) {
+    this.hash = hash || ZERO_HASH;
+    this.height =  height || 0;
+
+    assert(Buffer.isBuffer(this.hash) && this.hash.length === 32);
+    assert(Number.isInteger(this.height));
+  }
+}
+
 /**
  * Index Options
- * @alias module:indexer.IndexOptions
  */
 
 class IndexOptions {
diff --git a/lib/indexer/layout.js b/lib/indexer/layout.js
index e2bc243c..3edbd9ed 100644
--- a/lib/indexer/layout.js
+++ b/lib/indexer/layout.js
@@ -9,12 +9,13 @@
 const bdb = require('bdb');
 
 /*
- * Index Database Layout:
- * To be extended by indexer implementations
+ * Index database layout:
+ * To be extended by indexer implementations.
+ *
  *  V -> db version
  *  O -> flags
- *  h[height] -> recent block hash
- *  R -> chain sync state
+ *  h[height] -> block hash
+ *  R -> index sync height
  */
 
 const layout = {
diff --git a/lib/indexer/records.js b/lib/indexer/records.js
deleted file mode 100644
index 7db64b94..00000000
--- a/lib/indexer/records.js
+++ /dev/null
@@ -1,152 +0,0 @@
-/*!
- * records.js - indexer records
- * Copyright (c) 2018, the bcoin developers (MIT License).
- * https://github.com/bcoin-org/bcoin
- */
-
-'use strict';
-
-/**
- * @module lib/records
- */
-
-const bio = require('bufio');
-const util = require('../utils/util');
-const consensus = require('../protocol/consensus');
-
-/**
- * Block Meta
- * @alias module:indexer.BlockMeta
- */
-
-class BlockMeta {
-  /**
-   * Create block meta.
-   * @constructor
-   * @param {Hash} hash
-   * @param {Number} height
-   */
-
-  constructor(hash, height) {
-    this.hash = hash || consensus.NULL_HASH;
-    this.height = height != null ? height : -1;
-  }
-
-  /**
-   * Clone the block.
-   * @returns {BlockMeta}
-   */
-
-  clone() {
-    return new this.constructor(this.hash, this.height);
-  }
-
-  /**
-   * Get block meta hash as a buffer.
-   * @returns {Buffer}
-   */
-
-  toHash() {
-    return Buffer.from(this.hash, 'hex');
-  }
-
-  /**
-   * Instantiate block meta from chain entry.
-   * @private
-   * @param {IndexEntry} entry
-   */
-
-  fromEntry(entry) {
-    this.hash = entry.hash;
-    this.height = entry.height;
-    return this;
-  }
-
-  /**
-   * Instantiate block meta from json object.
-   * @private
-   * @param {Object} json
-   */
-
-  fromJSON(json) {
-    this.hash = util.revHex(json.hash);
-    this.height = json.height;
-    return this;
-  }
-
-  /**
-   * Instantiate block meta from serialized tip data.
-   * @private
-   * @param {Buffer} data
-   */
-
-  fromRaw(data) {
-    const br = bio.read(data);
-    this.hash = br.readHash('hex');
-    this.height = br.readI32();
-    return this;
-  }
-
-  /**
-   * Instantiate block meta from chain entry.
-   * @param {IndexEntry} entry
-   * @returns {BlockMeta}
-   */
-
-  static fromEntry(entry) {
-    return new this().fromEntry(entry);
-  }
-
-  /**
-   * Instantiate block meta from json object.
-   * @param {Object} json
-   * @returns {BlockMeta}
-   */
-
-  static fromJSON(json) {
-    return new this().fromJSON(json);
-  }
-
-  /**
-   * Instantiate block meta from serialized data.
-   * @param {Hash} hash
-   * @param {Buffer} data
-   * @returns {BlockMeta}
-   */
-
-  static fromRaw(data) {
-    return new this().fromRaw(data);
-  }
-
-  /**
-   * Serialize the block meta.
-   * @returns {Buffer}
-   */
-
-  toRaw() {
-    const bw = bio.write(36);
-    bw.writeHash(this.hash);
-    bw.writeI32(this.height);
-    return bw.render();
-  }
-
-  /**
-   * Convert the block meta to a more json-friendly object.
-   * @returns {Object}
-   */
-
-  toJSON() {
-    return {
-      hash: util.revHex(this.hash),
-      height: this.height
-    };
-  }
-}
-
-/*
- * Expose
- */
-
-exports.BlockMeta = BlockMeta;
-
-module.exports = exports;