1138343 - [UserDictionary] Instantiate and store an ArrayBuffer instead of a TypedArray during dictionary binary blob generation in KeyboardSettingsApp

Status: RESOLVED FIXED

(Firefox OS Graveyard :: Gaia::Keyboard, defect)

Description

[John Lu [:mnjul][Please NI or I'll miss]]

+++ This bug was initially created as a clone of Bug #1102834 +++

Bug 1102834 generated and stored the user dictionary blob as a Uint8Array, in KeyboardSettingsApp. IndexedDB does the serialization/marshalling wonderfully so KeyboardApp latin.js loads the blob as Uint8Array too.

However, in predictions.js we're also creating create new Uint8Array views for that incoming "blob". Now, at [1], the offset parameter will not see any effect: the second constructor for Uint8Array (see [2]) is called, instead of the fourth, because "buffer" in that context, when called with UserDictionary blob, is a Uint8Array.

Thus the "tree" structure is completely wrong and the prediction mechanism breaks.

[1] https://github.com/mozilla-b2g/gaia/blob/master/apps/keyboard/js/imes/latin/predictions.js#L196
[2] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array

Let's amend WordListConverter to return an ArrayBuffer to store into IndexedDB (I did a quick test and that seemed to work).

Note that other callers of predictions.js pass ArrayBuffer (either from XHR for built-in dics or IndexedDB as in bug 1029951) so this is kinda a design oversight during bug 1102834.

Without this bug fixed I can't progress on bug 1102835.

Comment 1

[GitHub Autolander Bot]

Attachment: [gaia] mnjul:bug_1138343_arraybuffer_userdict > mozilla-b2g:master

Comment 2

[John Lu [:mnjul][Please NI or I'll miss]]

Comment on attachment 8571329 [details] [review]
[gaia] mnjul:bug_1138343_arraybuffer_userdict > mozilla-b2g:master

Tim,

This is the UserDictionary "blocker" I talked about this afternoon. Contrary to what I'd said, I now don't think this actually needs priority to be reviewed (actual code changes are quite minimal, though). I think my bug 1102835 work can continue by overlaying on this patch.

Still, thanks for your time on reviewing this!

Comment 3

[Tim Guan-tin Chien [:timdream] (please needinfo)]

Comment on attachment 8571329 [details] [review]
[gaia] mnjul:bug_1138343_arraybuffer_userdict > mozilla-b2g:master

I step on the same mistake once! Sorry for not caught this in the first review!

Comment 4

[GitHub Autolander Bot]

Pull request has landed in master: https://github.com/mozilla-b2g/gaia/commit/bf2b7d41985f2588cb2707adeda7d695dced49bc