[Qemu-devel] [PATCH v2 00/14] Add qapi-to-JSON output visitor

[Eric Blake]

Prerequisites:
+ my qapi cleanups subset E v8:
https://lists.gnu.org/archive/html/qemu-devel/2015-12/msg03863.html

I wrote this series for several reasons:
1. I've been doing a lot of churn in the qapi visitor interfaces
lately; adding a new visitor is good proof whether the changes
still make sense
2. Alexander ended up writing his own simple JSON generator as
qjson.c in his work for vmstate self-description, rather than
reusing existing code, because the QObject JSON generator does
not have an easy entry point
3. Fam commented while trying to enhance 'qemu-img map' that we
are rather wasteful in that there is no way to go directly from
a qapi type to JSON without an intermediate QObject creation

v2 notes:
Fix bugs so that 'make check' and qemu-iotests pass at all points.
Rebase on top of qapi cleanups subset E v8.

Promote out of RFC.  However, in this version, I'm still
presenting two alternative solutions: either patch 8 (keep the
qjson.h interface) or patches 10-11 (completely drop qjson.h,
by inlining its contents but adding more glue in vmstate.c).
Patch 9 is a revert to show that the two alternatives are
orthogonal; the final series won't need a revert.  I'd welcome
opinions on which alternative to stick with.

Backport diffstat (renames of 1 and 14 confuse the stats):

001/14:[down] 'qapi: Rename (one) qjson.h to qobject-json.h'
002/14:[----] [--] 'qapi: Improve use of qmp/types.h'
003/14:[----] [--] 'qapi: Factor out JSON string escaping'
004/14:[0002] [FC] 'qapi: Factor out JSON number formatting'
005/14:[----] [--] 'qapi: Use qstring_append_chr() where appropriate'
006/14:[0016] [FC] 'qapi: Add qstring_append_format()'
007/14:[0063] [FC] 'qapi: add json output visitor'
008/14:[0008] [FC] 'qjson: Simplify by using json-output-visitor'
009/14:[down] 'Revert "qjson: Simplify by using json-output-visitor"'
010/14:[down] 'vmstate: use new JSON output visitor'
011/14:[down] 'qjson: Remove unused file'
012/14:[----] [--] 'qapi: Add qobject_to_json_pretty_prefix()'
013/14:[0004] [FC] 'qapi: Support pretty printing in JSON output visitor'
014/14:[down] 'qemu-img: Use new JSON output formatter'

v1 (RFC) notes:
https://lists.gnu.org/archive/html/qemu-devel/2015-12/msg01760.html

Eric Blake (14):
  qapi: Rename (one) qjson.h to qobject-json.h
  qapi: Improve use of qmp/types.h
  qapi: Factor out JSON string escaping
  qapi: Factor out JSON number formatting
  qapi: Use qstring_append_chr() where appropriate
  qapi: Add qstring_append_format()
  qapi: add json output visitor
  qjson: Simplify by using json-output-visitor
  Revert "qjson: Simplify by using json-output-visitor"
  vmstate: use new JSON output visitor
  qjson: Remove unused file
  qapi: Add qobject_to_json_pretty_prefix()
  qapi: Support pretty printing in JSON output visitor
  qemu-img: Use new JSON output formatter

 MAINTAINERS                                   |   2 +-
 Makefile.objs                                 |   1 -
 balloon.c                                     |   2 +-
 block.c                                       |   2 +-
 block/archipelago.c                           |   2 +-
 block/nbd.c                                   |   2 +-
 block/quorum.c                                |   2 +-
 blockjob.c                                    |   2 +-
 hw/core/qdev.c                                |   2 +-
 hw/misc/pvpanic.c                             |   2 +-
 hw/net/virtio-net.c                           |   2 +-
 hw/pci/pcie_aer.c                             |   1 +
 include/migration/vmstate.h                   |   4 +-
 include/qapi/json-output-visitor.h            |  25 ++
 include/qapi/qmp/{qjson.h => qobject-json.h}  |   1 +
 include/qapi/qmp/qstring.h                    |  12 +-
 include/qapi/qmp/types.h                      |   1 -
 include/qjson.h                               |  29 --
 migration/savevm.c                            |  66 ++--
 migration/vmstate.c                           |  63 ++--
 monitor.c                                     |   8 +-
 qapi/Makefile.objs                            |   2 +-
 qapi/json-output-visitor.c                    | 222 ++++++++++++
 qapi/qmp-dispatch.c                           |   1 +
 qapi/qmp-event.c                              |   2 +-
 qemu-img.c                                    |  69 ++--
 qga/main.c                                    |   2 +-
 qjson.c                                       | 129 -------
 qobject/Makefile.objs                         |   3 +-
 qobject/json-parser.c                         |  14 +-
 qobject/{qjson.c => qobject-json.c}           | 147 ++------
 qobject/qobject.c                             |   7 +-
 qobject/qstring.c                             | 117 ++++++-
 target-s390x/kvm.c                            |   2 +-
 tests/.gitignore                              |   3 +-
 tests/Makefile                                |  14 +-
 tests/{check-qjson.c => check-qobject-json.c} |  86 ++++-
 tests/libqtest.c                              |   2 +-
 tests/qemu-iotests/043.out                    |  22 +-
 tests/test-json-output-visitor.c              | 482 ++++++++++++++++++++++++++
 tests/test-qmp-input-strict.c                 |   1 +
 tests/test-qmp-input-visitor.c                |   1 +
 tests/test-qmp-output-visitor.c               |   1 +
 tests/test-visitor-serialization.c            |   1 +
 ui/spice-core.c                               |   2 +-
 vl.c                                          |   2 +-
 46 files changed, 1126 insertions(+), 439 deletions(-)
 create mode 100644 include/qapi/json-output-visitor.h
 rename include/qapi/qmp/{qjson.h => qobject-json.h} (90%)
 delete mode 100644 include/qjson.h
 create mode 100644 qapi/json-output-visitor.c
 delete mode 100644 qjson.c
 rename qobject/{qjson.c => qobject-json.c} (50%)
 rename tests/{check-qjson.c => check-qobject-json.c} (95%)
 create mode 100644 tests/test-json-output-visitor.c

-- 
2.4.3