Ian Campbell f02221a794 pkg/jsonmessage: Use terminfo rather than open coding ANSI escape codes ... Although our use of ANSI codes here is rather simple it is generally good practice to use terminfo in order to be portable to different terminal emulators. Vendor github.com/Nvveen/Gotty (actually my fork with a fix, see https://github.com/Nvveen/Gotty/pull/1) and use that to parse the terminfo files. Note that "\e]2K" (clear entire line) is not covered by terminfo. We can achieve the same end by first clearing from begining of line to cursor (el1="\e]1K") and then clearing from cursor to end of line (el="\e]k"). Test suite has been updated and forces (either directly or by setting $TERM to something highly unlikely to exist) the use of the non-terminfo fallbacks which retains the same output behaviour as previously. This is preferable even to relying on a well-known and relatively static terminfo (like vt102) since even that in principal might have different terminfo encodings. In case terminfo is not available at all for $TERM or doesn't expose the specific capabilities which we use then fall back to the previous manual escapes, with the exception that we avoid "\e]2K" as discussed above. Tested with a manual docker pull with rxvt-unicode ($TERM=rxvt-unicode), xterm ($TERM=xterm), mlterm ($TERM=mlterm) and aterm ($TERM=kterm). Signed-off-by: Ian Campbell <ian.campbell@docker.com>		2016-11-11 11:40:53 +00:00
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Gotty	pkg/jsonmessage: Use terminfo rather than open coding ANSI escape codes	2016-11-11 11:40:53 +00:00