Merge pull request MetaMask#4570 from MetaMask/persistence-stream-fix

background - persistence pipeline - fix persistence bug

Author: kumavis

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Current Master
 
+- Fix bug where metamask data would stop being written to disk after prolonged use
 - Fix bug where account reset did not work with custom RPC providers.
 - Fix bug where nonce mutex was never released
 - Stop reloading browser page on Ethereum network change

app/scripts/background.js

@@ -16,6 +16,7 @@ const ExtensionPlatform = require('./platforms/extension')
 const Migrator = require('./lib/migrator/')
 const migrations = require('./migrations/')
 const PortStream = require('./lib/port-stream.js')
+const createStreamSink = require('./lib/createStreamSink')
 const NotificationManager = require('./lib/notification-manager.js')
 const MetamaskController = require('./metamask-controller')
 const firstTimeState = require('./first-time-state')
@@ -273,7 +274,7 @@ function setupController (initState, initLangCode) {
     asStream(controller.store),
     debounce(1000),
     storeTransform(versionifyData),
-    storeTransform(persistData),
+    createStreamSink(persistData),
     (error) => {
       log.error('MetaMask - Persistence pipeline failed', error)
     }
@@ -289,20 +290,21 @@ function setupController (initState, initLangCode) {
     return versionedData
   }
 
-  function persistData (state) {
+  async function persistData (state) {
     if (!state) {
       throw new Error('MetaMask - updated state is missing', state)
     }
     if (!state.data) {
       throw new Error('MetaMask - updated state does not have data', state)
     }
     if (localStore.isSupported) {
-      localStore.set(state)
-      .catch((err) => {
+      try {
+        await localStore.set(state)
+      } catch (err) {
+        // log error so we dont break the pipeline
         log.error('error setting state in local store:', err)
-      })
+      }
     }
-    return state
   }
 
   //

app/scripts/lib/createStreamSink.js

@@ -0,0 +1,24 @@
+const WritableStream = require('readable-stream').Writable
+const promiseToCallback = require('promise-to-callback')
+
+module.exports = createStreamSink
+
+
+function createStreamSink(asyncWriteFn, _opts) {
+  return new AsyncWritableStream(asyncWriteFn, _opts)
+}
+
+class AsyncWritableStream extends WritableStream {
+
+  constructor (asyncWriteFn, _opts) {
+    const opts = Object.assign({ objectMode: true }, _opts)
+    super(opts)
+    this._asyncWriteFn = asyncWriteFn
+  }
+
+  // write from incomming stream to state
+  _write (chunk, encoding, callback) {
+    promiseToCallback(this._asyncWriteFn(chunk, encoding))(callback)
+  }
+
+}