lowlevelup: automatic dummies.

lib/blockchain/chaindb.js

@@ -27,7 +27,6 @@ const ChainEntry = require('./chainentry');
 const TXMeta = require('../primitives/txmeta');
 const U8 = encoding.U8;
 const U32 = encoding.U32;
-const DUMMY = Buffer.from([0]);
 
 /**
  * The database backend for the {@link Chain} object.
@@ -1318,7 +1317,7 @@ ChainDB.prototype._save = async function save(entry, block, view) {
 
   // Tip index.
   this.del(layout.p(entry.prevBlock));
-  this.put(layout.p(hash), DUMMY);
+  this.put(layout.p(hash), null);
 
   // Update state caches.
   this.saveUpdates();
@@ -1520,7 +1519,7 @@ ChainDB.prototype.reset = async function reset(block) {
 
     // Revert the tip index.
     this.del(layout.p(tip.hash));
-    this.put(layout.p(tip.prevBlock), DUMMY);
+    this.put(layout.p(tip.prevBlock), null);
 
     // Remove all records (including
     // main-chain-only records).
@@ -1859,7 +1858,7 @@ ChainDB.prototype.indexTX = function indexTX(tx, view, entry, index) {
     if (this.options.indexAddress) {
       let hashes = tx.getHashes(view);
       for (let addr of hashes)
-        this.put(layout.T(addr, hash), DUMMY);
+        this.put(layout.T(addr, hash), null);
     }
   }
 
@@ -1885,7 +1884,7 @@ ChainDB.prototype.indexTX = function indexTX(tx, view, entry, index) {
     if (!addr)
       continue;
 
-    this.put(layout.C(addr, hash, i), DUMMY);
+    this.put(layout.C(addr, hash, i), null);
   }
 };
 
@@ -1919,7 +1918,7 @@ ChainDB.prototype.unindexTX = function unindexTX(tx, view) {
       if (!addr)
         continue;
 
-      this.put(layout.C(addr, prevout.hash, prevout.index), DUMMY);
+      this.put(layout.C(addr, prevout.hash, prevout.index), null);
     }
   }
 

lib/db/lowlevelup.js

@@ -10,12 +10,14 @@
 const assert = require('assert');
 const Lock = require('../utils/lock');
 const co = require('../utils/co');
+
+const LOW = Buffer.from([0x00]);
+const HIGH = Buffer.from([0xff]);
+
 let VERSION_ERROR;
 
 /**
  * Extremely low-level version of levelup.
- * The only levelup feature it provides is
- * error-wrapping.
  *
  * This avoids pulling in extra deps and
  * lowers memory usage.
@@ -288,6 +290,9 @@ LowlevelUp.prototype.get = function get(key) {
  */
 
 LowlevelUp.prototype.put = function put(key, value) {
+  if (!value)
+    value = LOW;
+
   return new Promise((resolve, reject) => {
     if (!this.loaded) {
       reject(new Error('Database is closed.'));
@@ -396,10 +401,10 @@ LowlevelUp.prototype.approximateSize = function approximateSize(start, end) {
 
 LowlevelUp.prototype.compactRange = function compactRange(start, end) {
   if (!start)
-    start = Buffer.from([0x00]);
+    start = LOW;
 
   if (!end)
-    end = Buffer.from([0xff]);
+    end = HIGH;
 
   return new Promise((resolve, reject) => {
     if (!this.loaded) {
@@ -564,8 +569,8 @@ LowlevelUp.prototype.dump = async function dump() {
   let records = {};
 
   let items = await this.range({
-    gte: Buffer.from([0x00]),
+    gte: LOW,
-    lte: Buffer.from([0xff])
+    lte: HIGH
   });
 
   for (let i = 0; i < items.length; i++) {
@@ -678,7 +683,11 @@ function Batch(db) {
  */
 
 Batch.prototype.put = function put(key, value) {
+  if (!value)
+    value = LOW;
+
   this.batch.put(key, value);
+
   return this;
 };
 

lib/wallet/txdb.js

@@ -24,7 +24,6 @@ const Script = require('../script/script');
 const BlockMapRecord = records.BlockMapRecord;
 const OutpointMapRecord = records.OutpointMapRecord;
 const TXRecord = records.TXRecord;
-const DUMMY = Buffer.from([0]);
 
 /**
  * TXDB
@@ -299,7 +298,7 @@ TXDB.prototype.saveCredit = async function saveCredit(credit, path) {
   await this.addOutpointMap(coin.hash, coin.index);
 
   this.put(layout.c(coin.hash, coin.index), raw);
-  this.put(layout.C(path.account, coin.hash, coin.index), DUMMY);
+  this.put(layout.C(path.account, coin.hash, coin.index), null);
 
   this.coinCache.push(key, raw);
 };
@@ -763,7 +762,7 @@ TXDB.prototype._add = async function add(tx, block) {
       // We need to index every spender
       // hash to detect "passive"
       // replace-by-fee.
-      this.put(layout.r(hash), DUMMY);
+      this.put(layout.r(hash), null);
       return;
     }
 
@@ -919,24 +918,24 @@ TXDB.prototype.insert = async function insert(wtx, block) {
 
   // Save and index the transaction record.
   this.put(layout.t(hash), wtx.toRaw());
-  this.put(layout.m(wtx.ps, hash), DUMMY);
+  this.put(layout.m(wtx.ps, hash), null);
 
   if (!block)
-    this.put(layout.p(hash), DUMMY);
+    this.put(layout.p(hash), null);
   else
-    this.put(layout.h(height, hash), DUMMY);
+    this.put(layout.h(height, hash), null);
 
   // Do some secondary indexing for account-based
   // queries. This saves us a lot of time for
   // queries later.
   for (let account of details.accounts) {
-    this.put(layout.T(account, hash), DUMMY);
+    this.put(layout.T(account, hash), null);
-    this.put(layout.M(account, wtx.ps, hash), DUMMY);
+    this.put(layout.M(account, wtx.ps, hash), null);
 
     if (!block)
-      this.put(layout.P(account, hash), DUMMY);
+      this.put(layout.P(account, hash), null);
     else
-      this.put(layout.H(account, height, hash), DUMMY);
+      this.put(layout.H(account, height, hash), null);
   }
 
   // Update block records.
@@ -1105,12 +1104,12 @@ TXDB.prototype._confirm = async function confirm(wtx, block) {
   // updated. Also reindex for height.
   this.put(layout.t(hash), wtx.toRaw());
   this.del(layout.p(hash));
-  this.put(layout.h(height, hash), DUMMY);
+  this.put(layout.h(height, hash), null);
 
   // Secondary indexing also needs to change.
   for (let account of details.accounts) {
     this.del(layout.P(account, hash));
-    this.put(layout.H(account, height, hash), DUMMY);
+    this.put(layout.H(account, height, hash), null);
   }
 
   if (block) {
@@ -1431,12 +1430,12 @@ TXDB.prototype.disconnect = async function disconnect(wtx, block) {
   // block properties and reindex due
   // to the height change.
   this.put(layout.t(hash), wtx.toRaw());
-  this.put(layout.p(hash), DUMMY);
+  this.put(layout.p(hash), null);
   this.del(layout.h(height, hash));
 
   // Secondary indexing also needs to change.
   for (let account of details.accounts) {
-    this.put(layout.P(account, hash), DUMMY);
+    this.put(layout.P(account, hash), null);
     this.del(layout.H(account, height, hash));
   }
 

lib/wallet/walletdb.js

@@ -38,7 +38,6 @@ const PathMapRecord = records.PathMapRecord;
 const OutpointMapRecord = records.OutpointMapRecord;
 const TXRecord = records.TXRecord;
 const U32 = encoding.U32;
-const DUMMY = Buffer.from([0]);
 
 /**
  * WalletDB
@@ -1256,7 +1255,7 @@ WalletDB.prototype.savePath = async function savePath(wallet, path) {
   batch.put(layout.P(wid, hash), path.toRaw());
 
   // Wallet ID + Account Index + Address Hash -> Dummy
-  batch.put(layout.r(wid, path.account, hash), DUMMY);
+  batch.put(layout.r(wid, path.account, hash), null);
 };
 
 /**