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https://issues.apache.org/jira/browse/CB-1462?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sean Nikolai Fridman updated CB-1462:
-------------------------------------
Description:
*Note:* This is a bug in Android's native geolocation implementation. I can't
speak to what happens on other platforms. However, I get the feeling that the
bug is symptomatic of the JS implementation so it might very well exist on more
platforms.
*Description:* When watchPosition is called, it first calls getCurrentLocation
(resulting in a native call to getLocation), then makes a native call to
addWatch. In Android, addWatch callback ids and getLocation callback ids are
stored in separate data structures. The bug I'm seeing is, when I call
clearWatch before the watch operation's implicit getCurrentLocation callback is
invoked, the watch operation is removed/stopped in native, but the
corresponding getCurrentLocation operation is not. This is not compliant with
the W3C spec, which states that that no further callbacks for the watch
operation should be invoked. Worse, this causes a bug on Android where GPS is
never shut off! clearWatch stops the location listener *iff* {{callbacks.size +
watches.size == 0}}, and so if the callback hadn't been invoked yet...
_(Actually, skimming back through the code, I'm not seeing anywhere where the
location listener is stopped after a getCurrentPosition. Which may be another
issue... not sure.)_
*And the potential issue in Javascript is this:* if native has no knowledge of
which getCurrentLocation callbacks are part of a watch operation and which are
just normal independent ones, how can it possibly remove the callback id for
the implicit getCurrentLocation operation on clearWatch? And how can it
possibly know if it can really stop listening for location updates?
was:
Note: This is a bug in Android's native geolocation implementation. I can't
speak to what happens on other platforms. However, I get the feeling that the
bug is symptomatic of the JS implementation so it might very well exist on more
platforms.
Description: When watchPosition is called, it first calls getCurrentLocation
(resulting in a native call to getLocation), then makes a native call to
addWatch. In Android, addWatch callback ids and getLocation callback ids are
stored in separate data structures. The bug I'm seeing is, when I call
clearWatch before the watch operation's implicit getCurrentLocation callback is
invoked, the watch operation is removed/stopped in native, but the
corresponding getCurrentLocation operation is not. This is not compliant with
the W3C spec, which states that that no further callbacks for the watch
operation should be invoked. Worse, this causes a bug on Android where GPS is
never shut off! clearWatch stops the location listener *iff* {{callbacks.size +
watches.size == 0}}, and so if the callback hadn't been invoked yet...
_(Actually, skimming back through the code, I'm not seeing anywhere where the
location listener is stopped after a getCurrentPosition. Which may be another
issue... not sure.)_
And the potential issue in Javascript is this: if native has no knowledge of
which getCurrentLocation callbacks are part of a watch operation and which are
just normal independent ones, how can it possibly remove the callback id for
the implicit getCurrentLocation operation on clearWatch? And how can it
possibly know if it can really stop listening for location updates?
> False logic for native watchPosition/clearWatch
> -----------------------------------------------
>
> Key: CB-1462
> URL: https://issues.apache.org/jira/browse/CB-1462
> Project: Apache Cordova
> Issue Type: Bug
> Components: Android, CordovaJS
> Affects Versions: 2.0.0
> Reporter: Sean Nikolai Fridman
> Assignee: Joe Bowser
> Labels: clearwatch, geolocation, watchposition
>
> *Note:* This is a bug in Android's native geolocation implementation. I can't
> speak to what happens on other platforms. However, I get the feeling that the
> bug is symptomatic of the JS implementation so it might very well exist on
> more platforms.
> *Description:* When watchPosition is called, it first calls
> getCurrentLocation (resulting in a native call to getLocation), then makes a
> native call to addWatch. In Android, addWatch callback ids and getLocation
> callback ids are stored in separate data structures. The bug I'm seeing is,
> when I call clearWatch before the watch operation's implicit
> getCurrentLocation callback is invoked, the watch operation is
> removed/stopped in native, but the corresponding getCurrentLocation operation
> is not. This is not compliant with the W3C spec, which states that that no
> further callbacks for the watch operation should be invoked. Worse, this
> causes a bug on Android where GPS is never shut off! clearWatch stops the
> location listener *iff* {{callbacks.size + watches.size == 0}}, and so if the
> callback hadn't been invoked yet...
> _(Actually, skimming back through the code, I'm not seeing anywhere where the
> location listener is stopped after a getCurrentPosition. Which may be another
> issue... not sure.)_
> *And the potential issue in Javascript is this:* if native has no knowledge
> of which getCurrentLocation callbacks are part of a watch operation and which
> are just normal independent ones, how can it possibly remove the callback id
> for the implicit getCurrentLocation operation on clearWatch? And how can it
> possibly know if it can really stop listening for location updates?
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