760347 - nsDeviceSensor.cpp ASSERTs in debug builds for light sensors

Status: RESOLVED FIXED

(Core :: DOM: Device Interfaces, defect)

Description

[Dave Hylands [:dhylands]]

I'm hitting the following assert in B2G on debug builds:
Assertion failure: i < Length() (invalid array index), at ../../dist/include/nsTArray.h:535

This appears to be occuring with light sensors which only have a single value. The nsDeviceSensors::Notify function blindly pulls 3 values which causes the assert.

Comment 1

[Dave Hylands [:dhylands]]

Attachment: One way of resolving the problem.

Comment 2

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

I would do

 const InfallibleTArray<float>& values = aSensorData.values();
 size_t len = values.Length();
 double x = len > 0 ? values[0] : 0.0;
 double y = len > 1 ? values[1] : 0.0;
 //...

Comment 3

[Dave Hylands [:dhylands]]

Attachment: Proposed patch for bug 760347 v2

Bah. Humbug.

OK - I like the looks of your version better.

Comment 4

[Gregor Wagner [:gwagner]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/3524b3fe9492

Comment 5

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/3524b3fe9492