make sure no trailing spaces

[crquan]

Closes #99 text log should not have trailing spaces.

just reorganize the patch into 3 commits:
03377c6 rename f.appendKeyValue to printKeyValue
a243bba share common calling path in printKeyValue
dcbe8d6 make sure no leading or trailing spaces

In benchmark testing, it increased ~300 ns/op in SmallTextFormatter,
that should be due to the extra slice operation [1:];
in LargeTextFormatter it reduced ~700 ns/op;

BenchmarkSmallTextFormatter       200000             10683 ns/op           8.14 MB/s
BenchmarkLargeTextFormatter        30000             43537 ns/op           6.59 MB/s

BenchmarkSmallTextFormatter       200000             10996 ns/op           7.82 MB/s
BenchmarkLargeTextFormatter        30000             42862 ns/op           6.67 MB/s

Signed-off-by: Derek Che drc@yahoo-inc.com

[sirupsen]

I think trimSpaces is heavy handed, rather you should be able to pass an argument to appendKeyValue to remove the space, or always return b[0..len(b)-2]—the latter seems simpler, I prefer that one since there'll always be only one empty space. A comment would be appropriate too, since it's not obvious why that is.

Thanks for working on this!

[crquan]

or maybe code like this, just remove one possible space,

        if byts[len(byts)-1] == ' ' {
                byts = byts[:len(byts)-1]
        }

[crquan]

I have another TestColorPrint which tests how many spaces can the printColored func make: there could be many of them:

=== RUN TestColorPrint
"\x1b[31mPANI\x1b[0m[0000] msg content                                  \n"

So it's better to run in a loop:

for byts[len(byts)-1] == ' ' {
    byts = byts[:len(byts)-1]
}

or call bytes.TrimRightFunc:

byts = bytes.TrimRightFunc(byts, unicode.IsSpace)

[crquan]

@sirupsen do you have an update on this? I'm looking into this because docker code is referencing here, and every docker ci has log lines ends a space.
https://ci.dockerproject.com/github.com/docker/docker/commit/e00e161f4738cede19b37f4cd33ae643863ea570?branch=10081-fix-renaming

[sirupsen]

Can you squash? Otherwise looks good

[crquan]

this was initially in a single patch but I have split it into 3 separate to make each one's intention be clear; now to squash them is surely easy, but why does here prefer a squashed single commit? or do you have any worries on number of commits?