hg: openjfx/8/graphics/rt: Lens: Set environment variable LENS_BACKTRACE to a list of tags to get backtraces.

[hang.vo at oracle.com]

Changeset: 4299aa1f23b7
Author:    Daniel Blaukopf <daniel.blaukopf at oracle.com>
Date:      2013-02-26 14:42 +0200
URL:       http://hg.openjdk.java.net/openjfx/8/graphics/rt/rev/4299aa1f23b7

Lens: Set environment variable LENS_BACKTRACE to a list of tags to get backtraces.

If you set the environment variable LENS_BACKTRACE to a comma-separated list of
tags then you will get a backtrace whenever a logging message is written that
contains that tag. The backtrace includes both C and Java stacks.

For example,

- If you set LENS_BACKTRACE=drawbegin,drawEnd then you get a backtrace on any
  log message including either of these words.
- If you set LENS_BACKTRACE=LensWindowManager.c:352 then get a backtrace on a
  log message at that specific line.
- If you set LENS_BACKTRACE=LensWindowManager.c then get a backtrace on any log
  message in that file

Note that,

- The log message has to actually be written for the backtrace to be triggered.
- If you set backtrace tags and don't set -Dlog.lens then nothing will happen.
- Tags are case-sensitive
- A tag can contain a space, in which case you need to define it in quotes. For
  example, LENS_BACKTRACE="Focus requested"
- A tag can contain a comma, in which case you need to escape it with a
  backslash and use quotes. For example, LENS_BACKTRACE="x=0\, y=0"

! glass/glass-lib-lens/src/LensCommon.h
! glass/glass-lib-lens/src/LensLogger.c