From eac155d3b82c50b99f91b3de63618cad1fae0adb Mon Sep 17 00:00:00 2001
From: Steve Howell <showell30@yahoo.com>
Date: Wed, 2 Aug 2017 15:23:05 -0400
Subject: [PATCH] unread: Use reverse_lookup in unread_topic_counter.

---
 frontend_tests/node_tests/unread.js |  9 -------
 static/js/unread.js                 | 39 +++++++++++------------------
 2 files changed, 15 insertions(+), 33 deletions(-)

diff --git a/frontend_tests/node_tests/unread.js b/frontend_tests/node_tests/unread.js
index a28a0caf13..97c8c3d9f9 100644
--- a/frontend_tests/node_tests/unread.js
+++ b/frontend_tests/node_tests/unread.js
@@ -466,14 +466,5 @@ stream_data.get_stream_id = function () {
     unread.process_read_message(message);
     var counts = unread.get_counts();
     assert.equal(counts.private_message_count, 0);
-
-    // Test undefined stream_id
-    message = { type: 'stream' };
-
-    global.blueslip.error = function (msg) {
-        assert.equal(msg, 'No stream_id found for message undefined');
-    };
-
-    unread.process_read_message(message);
 }());
 
diff --git a/static/js/unread.js b/static/js/unread.js
index 358f2ba89d..214b1aa124 100644
--- a/static/js/unread.js
+++ b/static/js/unread.js
@@ -77,30 +77,30 @@ exports.unread_topic_counter = (function () {
     }
 
     var unread_topics = num_dict(); // dict of stream -> topic -> msg id
+    var reverse_lookup = num_dict();
 
     self.clear = function () {
         unread_topics = num_dict();
+        reverse_lookup = num_dict();
     };
 
-    self.update = function (stream_id, topic, new_topic, msg_id) {
-        self.del(stream_id, topic, msg_id);
+    self.update = function (msg_id, stream_id, new_topic) {
+        self.del(msg_id);
         self.add(stream_id, new_topic, msg_id);
     };
 
     self.add = function (stream_id, topic, msg_id) {
         unread_topics.setdefault(stream_id, str_dict());
-        unread_topics.get(stream_id).setdefault(topic, num_dict());
-        unread_topics.get(stream_id).get(topic).set(msg_id, true);
+        var dict = unread_topics.get(stream_id).setdefault(topic, num_dict());
+        dict.set(msg_id, true);
+        reverse_lookup.set(msg_id, dict);
     };
 
-
-    self.del = function (stream_id, topic, msg_id) {
-        var stream_dict = unread_topics.get(stream_id);
-        if (stream_dict) {
-            var topic_dict = stream_dict.get(topic);
-            if (topic_dict) {
-                topic_dict.del(msg_id);
-            }
+    self.del = function (msg_id) {
+        var dict = reverse_lookup.get(msg_id);
+        if (dict) {
+            dict.del(msg_id);
+            reverse_lookup.del(msg_id);
         }
     };
 
@@ -219,10 +219,9 @@ exports.message_unread = function (message) {
 exports.update_unread_topics = function (msg, event) {
     if (event.subject !== undefined) {
         exports.unread_topic_counter.update(
+            msg.id,
             msg.stream_id,
-            msg.subject,
-            event.subject,
-            msg.id
+            event.subject
         );
     }
 };
@@ -259,15 +258,7 @@ exports.process_read_message = function (message) {
     }
 
     if (message.type === 'stream') {
-        if (message.stream_id === undefined) {
-            blueslip.error('No stream_id found for message ' + message.id);
-            return;
-        }
-        exports.unread_topic_counter.del(
-            message.stream_id,
-            message.subject,
-            message.id
-        );
+        exports.unread_topic_counter.del(message.id);
     }
 
     exports.unread_mentions_counter.del(message.id);