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https://issues.apache.org/jira/browse/CB-638?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13439582#comment-13439582
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Andrew Grieve commented on CB-638:
----------------------------------
I've checked in the first round of changes for this. Modes can be tested in the
mobile-spec exec() benchmark.
jsToNativeModes = {
PROMPT: 0,
JS_OBJECT: 1,
LOCATION_CHANGE: 2 // Not yet implemented
},
nativeToJsModes = {
// Polls for messages using the prompt() bridge.
POLLING: 0,
// Does an XHR to a local server, which will send back messages. This is
// broken on ICS when a proxy server is configured.
HANGING_GET: 1,
// For LOAD_URL to be viable, it would need to have a work-around for
// the bug where the soft-keyboard gets dismissed when a message is
sent.
LOAD_URL: 2,
// For the ONLINE_EVENT to be viable, it would need to intercept all
event
// listeners (both through addEventListener and window.ononline) as well
// as set the navigator property itself.
ONLINE_EVENT: 3,
// Uses reflection to access private APIs of the WebView that can send
JS
// to be executed.
// Requires Android 3.2.4 or above.
PRIVATE_API: 4
};
-I've not implemented the any keyboard work-arounds for LOAD_URL
-I've not added a workaround for hiding online/offline events from changing
-JS_OBJECT probably needs a better enable/disable detection. Right now it's
disabled only for the 2.3 emulator instead of checking for JSC (via
http://stackoverflow.com/questions/6768474/how-can-i-detect-which-javascript-engine-v8-or-jsc-is-used-at-runtime-in-andro)
Some initial benchmark results from my Galaxy Nexus (echos per second, bigger
is better, payload size=500 bytes):
Sync JS->Native:
PROMPT: 570
JS_OBJECT: 800
Using JS_OBJECT for JS->Native and async Native->Response:
Native->JS POLLING+PROMPT: 100
Native->JS HANGING_GET: 75-90
Native->JS LOAD_URL: 160
Native->JS ONLINE_EVENT+PROMPT: 200-270
Native->JS PRIVATE_API: 340
ONLINE_EVENT being faster than LOAD_URL surprised me. Especially since it can
be made even a bit faster if it uses JS_OBJECT to retrieve the message instead
of PROMPT.
Still to do:
-Implement LOCATION_CHANGE JS->Native mode
-Add detection logic for JS_OBJECT support (this will involve loading a test
page to run some JS)
-Add hiding of ONLINE_EVENTS changes from the app via
cordova.addWindowEventHandler() and navigator.__defineGetter__('onLine', ...)
-Make POLLING and ONLINE_EVENT be able to use JS_OBJECT instead of always
PROMPT.
-Make POLLING & HANGING_GET retrieve all pending messages in one call instead
of one at a time
-Add mobile-spec test that ensures all modes work (when expected to)
Final Steps:
-Discuss changing the default bridge mode, as well as how to implement
fall-back modes.
> Slow native bridge (especially android)
> ---------------------------------------
>
> Key: CB-638
> URL: https://issues.apache.org/jira/browse/CB-638
> Project: Apache Cordova
> Issue Type: Improvement
> Components: Android
> Reporter: Lee Crossley
> Assignee: Andrew Grieve
> Priority: Critical
> Labels: 2.1.0
>
> Doing many native callbacks (such as writing files) has a significant
> overhead.
> Trigger.io's native bridge is more than 5 times faster than Cordova (on
> Android).
> http://trigger.io/cross-platform-application-development-blog/wp-content/uploads/2012/02/chart_1-21.png
> I'd love to see similar performance stats in Cordova.
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