[Qemu-devel] [PATCH 0/8] OptsVisitor: support / flatten integer ranges for repeating options

[Laszlo Ersek]

rfc->v1:
- addressed Paolo's comments for patches 1 and 2,
- patches 7 and 8 are new (unit tests),
- updated the cover letter to take native lists into account, plus
  cleaned it up.

Consider the following QAPI schema fragment, for the purpose of command
line parsing with OptsVisitor:

  { 'union': 'NumaOptions',
    'data': {
      'node': 'NumaNodeOptions',
      'mem' : 'NumaMemOptions' }}

  { 'type': 'NumaNodeOptions',
    'data': {
      '*nodeid': 'int',
      '*cpus'  : ['uint16'] }}

  { 'type': 'NumaMemOptions',
    'data': {
      '*nodeid': 'int',
      '*size'  : 'size' }}

(Commit eb7ee2cb ("qapi: introduce OptsVisitor") had originally
documented OptsVisitor's general schema requirements for parsing
repeated options such that the list element type had to be a struct with
one mandatory scalar field. Accordingly, the RFC version of this series
required for interval flattening that this underlying scalar type be an
integer type. However, since commit a678e26c ("qapi: pad GenericList
value fields to 64 bits") we've had reliable native lists; OptsVisitor
turns out to support them automatically.)

OptsVisitor already accepts the following command line with the above
schema:

  -numa node,nodeid=3,cpus=0,cpus=1,cpus=2,cpus=6,cpus=7,cpus=8

Paolo suggested in
<http://thread.gmane.org/gmane.comp.emulators.qemu/222589/focus=222732>
that OptsVisitor should allow the following shortcut:

  -numa node,nodeid=3,cpus=0-2,cpus=6-8

and that the code processing the "cpus" list should encounter all six
elements (0, 1, 2, 6, 7, 8) individually.

The series implements this feature. Both signed and unsigned values and
intervals are supported in general:

  * 0     (zero)
  * 1-5   (one to five)
  * 4-4   (four to four, range with one element)
  * -2    (minus two)
  * -5-8  (minus five to plus eight)
  * -9--6 (minus nine to minus six)

The restrictions imposed by the native list element's signedness and
size (in the above schema example, 'uint16') are enforced element-wise
as usual. That is, for 'uint16', the command line option

  -numa node,nodeid=3,cpus=65534-65537

is equivalent to

  -numa node,nodeid=3,cpus=65534,cpus=65535,cpus=65536,cpus=65537

and visit_type_uint16() [qapi/qapi-visit-core.c] will catch the first
element (= 65536) that has been parsed by opts_type_int() but cannot be
represented as 'uint16'.

Laszlo Ersek (8):
  OptsVisitor: introduce basic list modes
  OptsVisitor: introduce list modes for interval flattening
  OptsVisitor: opts_type_int(): recognize intervals when LM_IN_PROGRESS
  OptsVisitor: rebase opts_type_uint64() to parse_uint_full()
  OptsVisitor: opts_type_uint64(): recognize intervals when
    LM_IN_PROGRESS
  OptsVisitor: don't try to flatten overlong integer ranges
  add "test-int128" to .gitignore
  OptsVisitor: introduce unit tests, with test cases for range
    flattening

 tests/Makefile              |    6 +-
 qapi-schema-test.json       |   15 +++
 include/qapi/opts-visitor.h |    6 +
 qapi/opts-visitor.c         |  184 ++++++++++++++++++++++++-----
 tests/test-opts-visitor.c   |  275 +++++++++++++++++++++++++++++++++++++++++++
 .gitignore                  |    2 +
 6 files changed, 456 insertions(+), 32 deletions(-)
 create mode 100644 tests/test-opts-visitor.c