[chrome-gnome-shell/feature/extensions_sync] Do not route duplicate signals.

[Yuri Konotopov <ykonotopov src gnome org>]

commit 872a9b3cb1c9b68d888fae726bfb28d15fa58a3a
Author: Yuri Konotopov <ykonotopov gmail com>
Date:   Wed Aug 10 19:27:04 2016 +0300

    Do not route duplicate signals.
    
    For example, install action produces duplicate equal signals.

 extension/extension.js   |   12 ++++++++++++
 extension/include/gsc.js |   33 ++++++++++++++++++++++++++++++++-
 2 files changed, 44 insertions(+), 1 deletions(-)
---
diff --git a/extension/extension.js b/extension/extension.js
index 3421ec2..8865dec 100644
--- a/extension/extension.js
+++ b/extension/extension.js
@@ -67,10 +67,17 @@ chrome.runtime.onMessageExternal.addListener(function (request, sender, sendResp
        }
 });
 
+var lastPortMessage = {message: null, date: 0};
 var port = chrome.runtime.connectNative(NATIVE_HOST);
 port.onMessage.addListener(function (message) {
        if (message && message.signal && [SIGNAL_EXTENSIONS_CHANGED, 
SIGNAL_SHELL_APPEARED].indexOf(message.signal) !== -1)
        {
+               if((new Date().getTime()) - lastPortMessage.date < 500 && GSC.isSignalsEqual(message, 
lastPortMessage.message))
+               {
+                       lastPortMessage.date = new Date().getTime();
+                       return;
+               }
+
                chrome.tabs.query({
                        url: EXTENSIONS_WEBSITE + '*'
                },
@@ -80,6 +87,11 @@ port.onMessage.addListener(function (message) {
                                chrome.tabs.sendMessage(tabs[k].id, message);
                        }
                });
+
+               lastPortMessage = {
+                       message: message,
+                       date: new Date().getTime()
+               };
        }
 });
 
diff --git a/extension/include/gsc.js b/extension/include/gsc.js
index bedc8f7..8bc2f0f 100644
--- a/extension/include/gsc.js
+++ b/extension/include/gsc.js
@@ -73,6 +73,37 @@ GSC = (function() {
                        {
                                chrome.runtime.sendNativeMessage(NATIVE_HOST, request);
                        }
+               },
+
+               isSignalsEqual: function(newSignal, oldSignal) {
+                       if(!oldSignal || !newSignal)
+                               return false;
+
+                       if(!newSignal.signal || !oldSignal.signal || newSignal.signal !== oldSignal.signal)
+                               return false;
+
+                       if(newSignal.parameters)
+                       {
+                               if(!oldSignal.parameters)
+                                       return false;
+
+                               if(newSignal.parameters.length !== oldSignal.parameters.length)
+                                       return false;
+
+                               for(var i = 0; i < newSignal.parameters.length; i++)
+                               {
+                                       if(newSignal.parameters[i] !== oldSignal.parameters[i])
+                                       {
+                                               return false;
+                                       }
+                               }
+                       }
+                       else if (oldSignal.parameters)
+                       {
+                               return false;
+                       }
+
+                       return true;
                }
        };
-})();
\ No newline at end of file
+})();