isCompressed option to database

packages/db/src/Disk.ts

@@ -2,15 +2,17 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
+import { BaseDbOptions } from './types';
+
 import FileFlatDb from './engines/FileFlatDb';
 import LruDb from './engines/LruDb';
 import TransactionDb from './engines/TransactionDb';
 
 export default class DiskDb extends TransactionDb {
-  constructor (base: string, name: string) {
+  constructor (base: string, name: string, options?: BaseDbOptions) {
     super(
       new LruDb(
-        new FileFlatDb(base, name)
+        new FileFlatDb(base, name, options)
       )
     );
   }

packages/db/src/Memory.ts

@@ -2,11 +2,13 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
+import { BaseDbOptions } from './types';
+
 import MemoryDb from './engines/MemoryDb';
 import TransactionDb from './engines/TransactionDb';
 
 export default class Memory extends TransactionDb {
-  constructor () {
-    super(new MemoryDb());
+  constructor (options?: BaseDbOptions) {
+    super(new MemoryDb(options));
   }
 }

packages/db/src/engines/FileFlatDb.ts

@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-import { BaseDb, ProgressCb } from '../types';
+import { BaseDb, BaseDbOptions, ProgressCb } from '../types';
 
 import fs from 'fs';
 import mkdirp from 'mkdirp';
@@ -10,6 +10,7 @@ import path from 'path';
 import snappy from 'snappy';
 import assert from '@polkadot/util/assert';
 import logger from '@polkadot/util/logger';
+import isUndefined from '@polkadot/util/is/undefined';
 import bufferToU8a from '@polkadot/util/buffer/toU8a';
 import u8aToBuffer from '@polkadot/util/u8a/toBuffer';
 import u8aToHex from '@polkadot/util/u8a/toHex';
@@ -57,10 +58,14 @@ const l = logger('db/flat');
 export default class FileFlatDb implements BaseDb {
   private _fd: number;
   private _file: string;
+  private _isCompressed: boolean;
 
-  constructor (base: string, file: string = DEFAULT_FILE) {
+  constructor (base: string, file: string = DEFAULT_FILE, options: BaseDbOptions = {}) {
     this._fd = -1;
     this._file = path.join(base, file);
+    this._isCompressed = options && !isUndefined(options.isCompressed)
+      ? options.isCompressed
+      : false;
 
     mkdirp.sync(base);
   }
@@ -141,19 +146,19 @@ export default class FileFlatDb implements BaseDb {
   }
 
   private _deserializeValue (value: Buffer): Uint8Array | null {
-    // return bufferToU8a(value);
-
     return bufferToU8a(
-      snappy.uncompressSync(value)
+      this._isCompressed
+        ? snappy.uncompressSync(value)
+        : value
     );
   }
 
   private _serializeValue (value: Uint8Array): Buffer {
-    // return u8aToBuffer(value);
-
-    return snappy.compressSync(
-      u8aToBuffer(value)
-    );
+    return this._isCompressed
+      ? snappy.compressSync(
+        u8aToBuffer(value)
+      )
+      : u8aToBuffer(value);
   }
 
   private _serializeKey (key: Uint8Array): Buffer {

packages/db/src/engines/MemoryDb.ts

@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the ISC license. See the LICENSE file for details.
 
-import { BaseDb, ProgressCb } from '../types';
+import { BaseDb, BaseDbOptions, ProgressCb } from '../types';
 
 // import logger from '@polkadot/util/logger';
 // import u8aToHex from '@polkadot/util/u8a/toHex';
@@ -16,7 +16,7 @@ type Storage = {
 export default class MemoryDb implements BaseDb {
   private storage: Storage;
 
-  constructor () {
+  constructor (options?: BaseDbOptions) {
     this.storage = {};
   }
 

packages/db/src/types.d.ts

@@ -10,6 +10,10 @@ export type ProgressValue = {
 
 export type ProgressCb = (progress: ProgressValue) => void;
 
+export type BaseDbOptions = {
+  isCompressed?: boolean,
+};
+
 export interface BaseDb {
   close (): void;
   open (): void;