From be3b578267423f966c147b0317c535fa7cd3ec2b Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Sun, 15 May 2016 20:11:23 -0700
Subject: [PATCH] ldb refactor.

---
 lib/bcoin/ldb.js | 112 +++++++++++++++++++++++++++++++++--------------
 1 file changed, 79 insertions(+), 33 deletions(-)

diff --git a/lib/bcoin/ldb.js b/lib/bcoin/ldb.js
index eccfe318..acdac7ef 100644
--- a/lib/bcoin/ldb.js
+++ b/lib/bcoin/ldb.js
@@ -22,11 +22,13 @@ var db = {};
  * @param {Number} options.mapSize
  * @param {Boolean} options.writeMap
  * @param {String} options.db - Database backend (`"leveldb"` by default).
+ * @param {String} options.name - Database name.
+ * @param {String} options.location - Database location (overrides `name`).
  * @returns {LowlevelUp}
  */
 
 function ldb(options) {
-  var file = getLocation(options);
+  var file = ldb.getLocation(options);
 
   if (!db[file]) {
     if (!options)
@@ -52,14 +54,66 @@ function ldb(options) {
       mapSize: options.mapSize || 300 * (1024 << 20),
       writeMap: options.writeMap || false,
 
-      db: getBackend(options.db)
+      db: ldb.getBackend(options.db)
     });
   }
 
   return db[file];
 }
 
-function getLocation(options) {
+/**
+ * Get database name and extension based on options.
+ * @param {String} db
+ * @returns {Object}
+ */
+
+ldb.getName = function getName(db) {
+  var ext;
+
+  if (!db)
+    db = bcoin.db || 'leveldb';
+
+  if (db === 'leveldb')
+    name = 'leveldown';
+  else if (db === 'rocksdb')
+    name = 'rocksdown';
+  else if (db === 'lmdb')
+    name = 'lmdb';
+  else if (db === 'memory')
+    name = 'bst';
+  else
+    name = db;
+
+  switch (name) {
+    case 'leveldown':
+      ext = 'ldb';
+      break;
+    case 'rocksdown':
+      ext = 'rdb';
+      break;
+    case 'lmdb':
+      ext = 'lmdb';
+      break;
+    case 'bst':
+      ext = 'mem';
+      break;
+    default:
+      ext = 'db';
+      break;
+  }
+
+  return { name: name, ext: ext };
+};
+
+/**
+ * Get database location based on options.
+ * @param {Object} options
+ * @returns {String} Path.
+ */
+
+ldb.getLocation = function getLocation(options) {
+  var backend = ldb.getName(options.db);
+
   if (options.location)
     return options.location;
 
@@ -68,23 +122,20 @@ function getLocation(options) {
     + options.name
     + '-'
     + bcoin.network.get(options.network).type
-    + '.db';
-}
+    + '.'
+    + backend.ext;
+};
 
-function getBackend(backend) {
-  if (!backend)
-    backend = bcoin.db;
+/**
+ * Require database backend module.
+ * @param {String} db
+ * @returns {Object} Module.
+ */
 
-  if (!backend || backend === 'leveldb')
-    backend = 'leveldown';
-  else if (backend === 'rocksdb')
-    backend = 'rocksdown';
-  else if (backend === 'lmdb')
-    backend = 'lmdb';
-  else if (backend === 'memory')
-    backend = 'bst';
+ldb.getBackend = function getBackend(db) {
+  var backend = ldb.getName(db);
 
-  if (backend === 'bst')
+  if (backend.name === 'bst')
     return require('./bst');
 
   if (bcoin.isBrowser)
@@ -92,8 +143,8 @@ function getBackend(backend) {
 
   bcoin.ensurePrefix();
 
-  return require(backend);
-}
+  return require(backend.name);
+};
 
 /**
  * Destroy a database.
@@ -101,15 +152,15 @@ function getBackend(backend) {
  * @param {Function} callback
  */
 
-function destroy(options, callback) {
-  var file = getLocation(options);
-  var backend = getBackend(options.db);
+ldb.destroy = function destroy(options, callback) {
+  var file = ldb.getLocation(options);
+  var backend = ldb.getBackend(options.db);
 
   if (!backend.destroy)
     return utils.nextTick(callback);
 
   backend.destroy(file, callback);
-}
+};
 
 /**
  * Repair a database.
@@ -117,23 +168,18 @@ function destroy(options, callback) {
  * @param {Function} callback
  */
 
-function repair(options, callback) {
-  var file = getLocation(options);
-  var backend = getBackend(options.db);
+ldb.repair = function repair(options, callback) {
+  var file = ldb.getLocation(options);
+  var backend = ldb.getBackend(options.db);
 
   if (!backend.repair)
     return utils.asyncify(callback)(new Error('Cannot repair.'));
 
   backend.repair(file, callback);
-}
+};
 
 /*
  * Expose
  */
 
-exports = ldb;
-
-exports.destroy = destroy;
-exports.repair = repair;
-
-module.exports = exports;
+module.exports = ldb;