Re: [PATCH v4] json_writer: new routines to create data in JSON format

> From: Jeff Hostetler <jeffhost@microsoft.com>
> 
> Add a series of jw_ routines and "struct json_writer" structure to compose
> JSON data.  The resulting string data can then be output by commands wanting
> to support a JSON output format.
> 
> The json-writer routines can be used to generate structured data in a
> JSON-like format.  We say "JSON-like" because we do not enforce the Unicode
> (usually UTF-8) requirement on string fields.  Internally, Git does not
> necessarily have Unicode/UTF-8 data for most fields, so it is currently
> unclear the best way to enforce that requirement.  For example, on Linx
> pathnames can contain arbitrary 8-bit character data, so a command like
> "status" would not know how to encode the reported pathnames.  We may want
> to revisit this (or double encode such strings) in the future.
> 
> The initial use for the json-writer routines is for generating telemetry
> data for executed Git commands.  Later, we may want to use them in other
> commands, such as status.
> 
> Helped-by: René Scharfe <l.s.r@web.de>
> Helped-by: Wink Saville <wink@saville.com>
> Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
> Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
> ---
>  Makefile                    |   2 +
>  json-writer.c               | 395 +++++++++++++++++++++++++++++
>  json-writer.h               |  92 +++++++
>  t/helper/test-json-writer.c | 590 ++++++++++++++++++++++++++++++++++++++++++++
>  t/t0019-json-writer.sh      | 253 +++++++++++++++++++
>  5 files changed, 1332 insertions(+)
>  create mode 100644 json-writer.c
>  create mode 100644 json-writer.h
>  create mode 100644 t/helper/test-json-writer.c
>  create mode 100755 t/t0019-json-writer.sh
>