From 58eedd1c375372d6afbdd66cb945e894630800ea Mon Sep 17 00:00:00 2001
From: Tom Hacohen <tom@stosb.com>
Date: Fri, 15 Dec 2017 13:14:40 +0000
Subject: [PATCH] Cache the SyncGate calculations.

This was taking quite a lot of time and caching this significantly
improves performance.

We only need it because of the react-redux-router bug, but good to have
it in the meanwhile.
---
 package.json     |  2 ++
 src/SyncGate.tsx | 88 +++++++++++++++++++++++++++---------------------
 yarn.lock        | 10 ++++++
 3 files changed, 62 insertions(+), 38 deletions(-)

diff --git a/package.json b/package.json
index 1c6d9e3..f5c17db 100644
--- a/package.json
+++ b/package.json
@@ -23,6 +23,7 @@
     "redux-logger": "^3.0.6",
     "redux-persist": "^5.4.0",
     "redux-thunk": "^2.2.0",
+    "reselect": "^3.0.1",
     "sjcl": "git+https://github.com/etesync/sjcl",
     "urijs": "^1.16.1",
     "uuid": "^3.1.0"
@@ -46,6 +47,7 @@
     "@types/react-router-dom": "^4.2.3",
     "@types/redux-actions": "^2.2.3",
     "@types/redux-logger": "^3.0.5",
+    "@types/reselect": "^2.2.0",
     "@types/sjcl": "^1.0.28",
     "@types/urijs": "^1.15.34",
     "@types/uuid": "^3.4.3"
diff --git a/src/SyncGate.tsx b/src/SyncGate.tsx
index e332646..da36105 100644
--- a/src/SyncGate.tsx
+++ b/src/SyncGate.tsx
@@ -3,6 +3,7 @@ import { connect } from 'react-redux';
 import { Route, Switch, Redirect, withRouter } from 'react-router';
 
 import { List, Map } from 'immutable';
+import { createSelector } from 'reselect';
 
 import { routeResolver } from './App';
 
@@ -33,6 +34,49 @@ interface PropsTypeInner extends PropsType {
   entries: EntriesType;
 }
 
+const syncInfoSelector = createSelector(
+  (props: PropsTypeInner) => props.etesync,
+  (props: PropsTypeInner) => props.journals.value as List<EteSync.Journal>,
+  (props: PropsTypeInner) => props.entries,
+  (etesync, journals, entries) => {
+    return journals.reduce(
+      (ret, journal) => {
+        const derived = etesync.encryptionKey;
+        const journalEntries = entries.get(journal.uid);
+        const cryptoManager = new EteSync.CryptoManager(derived, journal.uid, journal.version);
+
+        let prevUid: string | null = null;
+
+        if (!journalEntries || !journalEntries.value) {
+          return ret;
+        }
+
+        // FIXME: Skip shared journals for now
+        if (journal.key) {
+          return ret;
+        }
+
+        const collectionInfo = journal.getInfo(cryptoManager);
+
+        const syncEntries = journalEntries.value.map((entry: EteSync.Entry) => {
+          let syncEntry = entry.getSyncEntry(cryptoManager, prevUid);
+          prevUid = entry.uid;
+
+          return syncEntry;
+        });
+
+        return ret.set(journal.uid, {
+          entries: syncEntries,
+          collection: collectionInfo,
+          journal,
+          journalEntries: journalEntries.value,
+        });
+      },
+      Map<string, SyncInfoJournal>()
+    );
+  },
+);
+
 class SyncGate extends React.PureComponent {
   props: PropsTypeInner;
 
@@ -68,42 +112,10 @@ class SyncGate extends React.PureComponent {
       return (<LoadingIndicator />);
     }
 
-    const derived = this.props.etesync.encryptionKey;
+    const journalMap = syncInfoSelector(this.props);
 
-    const journalMap = journals.reduce(
-      (ret, journal) => {
-        const journalEntries = this.props.entries.get(journal.uid);
-        const cryptoManager = new EteSync.CryptoManager(derived, journal.uid, journal.version);
-
-        let prevUid: string | null = null;
-
-        if (!journalEntries || !journalEntries.value) {
-          return ret;
-        }
-
-        // FIXME: Skip shared journals for now
-        if (journal.key) {
-          return ret;
-        }
-
-        const collectionInfo = journal.getInfo(cryptoManager);
-
-        const syncEntries = journalEntries.value.map((entry: EteSync.Entry) => {
-          let syncEntry = entry.getSyncEntry(cryptoManager, prevUid);
-          prevUid = entry.uid;
-
-          return syncEntry;
-        });
-
-        return ret.set(journal.uid, {
-          entries: syncEntries,
-          collection: collectionInfo,
-          journal,
-          journalEntries: journalEntries.value,
-        });
-      },
-      Map<string, SyncInfoJournal>()
-    );
+    const PimRouter = withRouter(Pim);
+    const JournalRouter = withRouter(Journal);
 
     return (
       <Switch>
@@ -117,7 +129,7 @@ class SyncGate extends React.PureComponent {
         <Route
           path={routeResolver.getRoute('pim')}
           render={({match, history}) => (
-            <Pim
+            <PimRouter
               etesync={this.props.etesync}
               syncInfo={journalMap}
               history={history}
@@ -127,7 +139,7 @@ class SyncGate extends React.PureComponent {
         <Route
           path={routeResolver.getRoute('journals._id')}
           render={({match}) => (
-            <Journal
+            <JournalRouter
               syncInfo={journalMap}
               match={match}
             />
@@ -145,7 +157,7 @@ const mapStateToProps = (state: StoreState, props: PropsType) => {
   };
 };
 
-// FIXME: withRouter is only needed here because of https://github.com/ReactTraining/react-router/issues/5795
+// FIXME: this and withRouters are only needed here because of https://github.com/ReactTraining/react-router/issues/5795
 export default withRouter(connect(
   mapStateToProps
 )(SyncGate));
diff --git a/yarn.lock b/yarn.lock
index 95e4f3a..4d13690 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -90,6 +90,12 @@
   dependencies:
     redux "^3.6.0"
 
+"@types/reselect@^2.2.0":
+  version "2.2.0"
+  resolved "https://registry.yarnpkg.com/@types/reselect/-/reselect-2.2.0.tgz#c667206cfdc38190e1d379babe08865b2288575f"
+  dependencies:
+    reselect "*"
+
 "@types/sjcl@^1.0.28":
   version "1.0.28"
   resolved "https://registry.yarnpkg.com/@types/sjcl/-/sjcl-1.0.28.tgz#4693eb6943e385e844a70fb25b4699db286c7214"
@@ -5021,6 +5027,10 @@ requires-port@1.0.x, requires-port@1.x.x, requires-port@~1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/requires-port/-/requires-port-1.0.0.tgz#925d2601d39ac485e091cf0da5c6e694dc3dcaff"
 
+reselect@*, reselect@^3.0.1:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/reselect/-/reselect-3.0.1.tgz#efdaa98ea7451324d092b2b2163a6a1d7a9a2147"
+
 resolve-dir@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/resolve-dir/-/resolve-dir-1.0.1.tgz#79a40644c362be82f26effe739c9bb5382046f43"