877010 - [A/V] Video application hardly controls scrolling up/down if there are many video files

Status: RESOLVED FIXED

(Firefox OS Graveyard :: Gaia::Video, defect, P1)

Description

[leo.bugzilla.gecko]

Precondition : There are more than 40 supported video files in sdcard.

After thumbnail retrieving finished, it's hard to scroll the list up/down.
This problem occurs only in portrait mode.
If I rotate device to vertical mode, it doesn't occur.

Comment 1

[David Flanagan [:djf]]

I've tested with more than 40 video files and did not have this problem. The test videos that the reporter demonstrated this bug with all had very long filenames.  I think that this bug may be a regression caused by bug 859284

Comment 2

[David Flanagan [:djf]]

I've confirmed that long filenames are causing an infinite loop of overflow events in video.js

Comment 3

[David Flanagan [:djf]]

To reproduce this bug, patch apps/video/js/metadata.js like this:

-    return filename.charAt(0).toUpperCase() + filename.slice(1);
+    return filename.charAt(0).toUpperCase() + filename.slice(1) +
+      "lots of extra characters here to make the name long";

That gives all videos titles that are too long to display in portrait mode, but can be displayed in landscape and triggers the infinite loop of title length adjustment.

Comment 4

[David Flanagan [:djf]]

Attachment: link to patch on github

Sam,

This is a follow up to your patch that used the overflow event to make video titles fit. We both missed a serious bug in that code. If the title was longer than 45 characters, we'd truncate it to 45 characters and then add the ... character, so it would be 46 characters.  If it still didn't fit, the overflow handler would be called again, and since it was greater than 45 characters, we'd repeat the same thing instead of going down to 42 characters as intended.

The infinite loop manifested as very slow scrolling speeds when there were lots of videos with long names.

The fix is just to set end to max - 1.  My patch also includes some simple code cleanup.  And also, in my testing, I could see the lines doing their adjustment, so I changed it to delete 4 characters at a time instead of 3 characters at a time.

There is a mini workweek going on in San Diego this week, and this bug is a priority to resolve this week, so a quick review would be appreciated!

Comment 5

[David Flanagan [:djf]]

Landed on master: https://github.com/mozilla-b2g/gaia/commit/f8acd88cab525158563e78ec1620a46e70963d6a

Comment 6

[John Ford [:jhford] CET/CEST Berlin Time]

Uplifted f8acd88cab525158563e78ec1620a46e70963d6a to:
v1-train: 5fc3b4cdabae8e930c8d9da4b7b376a3de9109e3

Comment 7

[:CSchmoeckel]

Added Video Suite Test Case #8521 [B2G Video] Navigation control remains smooth while scrolling up/down through many video file