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https://issues.apache.org/jira/browse/CB-2963?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Andrew Grieve resolved CB-2963.
-------------------------------
Resolution: Fixed
Fix Version/s: 2.7.0
Fixed (with tests).
JS commit:
https://git-wip-us.apache.org/repos/asf?p=cordova-js.git;a=commit;h=e80f4afdc14a5f28e41d075f3c3dbdbf3fbdbb34
Davide, thanks a tonne for your detailed debugging info!
> Javascript callback functions are not executed in the correct order
> -------------------------------------------------------------------
>
> Key: CB-2963
> URL: https://issues.apache.org/jira/browse/CB-2963
> Project: Apache Cordova
> Issue Type: Bug
> Components: Android
> Affects Versions: 2.5.0
> Reporter: Davide Maestroni
> Assignee: Andrew Grieve
> Fix For: 2.7.0
>
>
> I created an application which sends asynchronous notifications from the
> native to the Javascript side. I noticed that in some cases the Javascript
> code of the callbacks is not executed in the expected order.
> Let me show an example:
> # a native event trigger a notification to the Javascript side where a
> callback function (callback1 - part 1) gets correctly called
> # in the while, on the native side, a different notification is triggered
> # inside the Javascript code of the first callback the cordova.exec() API is
> issued
> # at this point the Javascript code of the second callback (callback2) is
> executed sequentially on the same thread
> # when the second callback completes, the final part of the code in the first
> callback (callback1 - part 2) is executed
> So that, if the callback functions are defined as below:
> {noformat}
> function callback1() {
> <callback1 - part 1>
> cordova.exec(...);
> <callback1 - part 2>
> }
> function callback2() {
> <callback2>
> }
> {noformat}
> the Javascript code gets executed in the following order:
> {noformat}
> <callback1 - part 1>
> cordova.exec(...);
> <callback2>
> <callback1 - part 2>
> {noformat}
> which is not the expected behavior.
> I believe the problem is related to the following lines of code in the
> _cordova.android.js_ file:
> {noformat}
> var messages = nativeApiProvider.get().exec(service, action,
> callbackId, argsJson);
> androidExec.processMessages(messages);
> {noformat}
> which get called if _jsToNativeBridgeMode == jsToNativeModes.JS_OBJECT_.
> That causes enqueued messages to get executed sequentially before the
> execution of the first callback is complete.
> An easy fix would be to change the above code into:
> {noformat}
> var messages = nativeApiProvider.get().exec(service, action,
> callbackId, argsJson);
> setTimeout(function() {
> androidExec.processMessages(messages);
> }, 0);
> {noformat}
> so that the enqueued messages are processed in the next Javascript loop.
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