Commit Graph

7 Commits

Author SHA1 Message Date
Markus Armbruster
87c16dceca qapi: Back out doc comments added just to please qapi.py
This reverts commit 3313b61's changes to tests/qapi-schema/, except
for tests/qapi-schema/doc-*.

We could keep some of these doc comments to serve as positive test
cases.  However, they don't actually add to what we get from doc
comment use in actual schemas, as we we don't test output matches
expectations, and don't systematically cover doc comment features.
Proper positive test coverage would be nice.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <1489582656-31133-4-git-send-email-armbru@redhat.com>
2017-03-16 07:13:01 +01:00
Marc-André Lureau
3313b6124b qapi: add qapi2texi script
As the name suggests, the qapi2texi script converts JSON QAPI
description into a texi file suitable for different target
formats (info/man/txt/pdf/html...).

It parses the following kind of blocks:

Free-form:

  ##
  # = Section
  # == Subsection
  #
  # Some text foo with *emphasis*
  # 1. with a list
  # 2. like that
  #
  # And some code:
  # | $ echo foo
  # | -> do this
  # | <- get that
  #
  ##

Symbol description:

  ##
  # @symbol:
  #
  # Symbol body ditto ergo sum. Foo bar
  # baz ding.
  #
  # @param1: the frob to frobnicate
  # @param2: #optional how hard to frobnicate
  #
  # Returns: the frobnicated frob.
  #          If frob isn't frobnicatable, GenericError.
  #
  # Since: version
  # Notes: notes, comments can have
  #        - itemized list
  #        - like this
  #
  # Example:
  #
  # -> { "execute": "quit" }
  # <- { "return": {} }
  #
  ##

That's roughly following the following EBNF grammar:

api_comment = "##\n" comment "##\n"
comment = freeform_comment | symbol_comment
freeform_comment = { "# " text "\n" | "#\n" }
symbol_comment = "# @" name ":\n" { member | tag_section | freeform_comment }
member = "# @" name ':' [ text ] "\n" freeform_comment
tag_section = "# " ( "Returns:", "Since:", "Note:", "Notes:", "Example:", "Examples:" ) [ text ]  "\n" freeform_comment
text = free text with markup

Note that the grammar is ambiguous: a line "# @foo:\n" can be parsed
both as freeform_comment and as symbol_comment.  The actual parser
recognizes symbol_comment.

See docs/qapi-code-gen.txt for more details.

Deficiencies and limitations:
- the generated QMP documentation includes internal types
- union type support is lacking
- type information is lacking in generated documentation
- doc comment error message positions are imprecise, they point
  to the beginning of the comment.
- a few minor issues, all marked TODO/FIXME in the code

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20170113144135.5150-16-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[test-qapi.py tweaked to avoid trailing empty lines in .out]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2017-01-16 10:10:35 +01:00
Eric Blake
7599697c66 qapi: Adjust names of implicit types
The original choice of ':obj-' as the prefix for implicit types
made it obvious that we weren't going to clash with any user-defined
names, which cannot contain ':'.  But now we want to create structs
for implicit types, to get rid of special cases in the generators,
and our use of ':' in implicit names needs a tweak to produce valid
C code.

We could transliterate ':' to '_', except that C99 mandates that
"identifiers that begin with an underscore are always reserved for
use as identifiers with file scope in both the ordinary and tag name
spaces".  So it's time to change our naming convention: we can
instead use the 'q_' prefix that we reserved for ourselves back in
commit 9fb081e0.  Technically, since we aren't planning on exposing
the empty type in generated code, we could keep the name ':empty',
but renaming it to 'q_empty' makes the check for startswith('q_')
cover all implicit types, whether or not code is generated for them.

As long as we don't declare 'empty' or 'obj' ticklish, it shouldn't
clash with c_name() prepending 'q_' to the user's ticklish names.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1458254921-17042-5-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-03-18 10:29:25 +01:00
Eric Blake
7264f5c50c qapi: Convert QType into QAPI built-in enum type
What's more meta than using qapi to define qapi? :)

Convert QType into a full-fledged[*] builtin qapi enum type, so
that a subsequent patch can then use it as the discriminator
type of qapi alternate types.  Fortunately, the judicious use of
'prefix' in the qapi definition avoids churn to the spelling of
the enum constants.

To avoid circular definitions, we have to flip the order of
inclusion between "qobject.h" vs. "qapi-types.h".  Back in commit
28770e0, we had the latter include the former, so that we could
use 'QObject *' for our implementation of 'any'.  But that usage
also works with only a forward declaration, whereas the
definition of QObject requires QType to be a complete type.

[*] The type has to be builtin, rather than declared in
qapi/common.json, because we want to use it for alternates even
when common.json is not included. But since it is the first
builtin enum type, we have to add special cases to qapi-types
and qapi-visit to only emit definitions once, even when two
qapi files are being compiled into the same binary (the way we
already handled builtin list types like 'intList').  We may
need to revisit how multiple qapi files share common types,
but that's a project for another day.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1449033659-25497-4-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2015-12-17 08:21:28 +01:00
Markus Armbruster
39a1815816 qapi: New QMP command query-qmp-schema for QMP introspection
qapi/introspect.json defines the introspection schema.  It's designed
for QMP introspection, but should do for similar uses, such as QGA.

The introspection schema does not reflect all the rules and
restrictions that apply to QAPI schemata.  A valid QAPI schema has an
introspection value conforming to the introspection schema, but the
converse is not true.

Introspection lowers away a number of schema details, and makes
implicit things explicit:

* The built-in types are declared with their JSON type.

  All integer types are mapped to 'int', because how many bits we use
  internally is an implementation detail.  It could be pressed into
  external interface service as very approximate range information,
  but that's a bad idea.  If we need range information, we better do
  it properly.

* Implicit type definitions are made explicit, and given
  auto-generated names:

  - Array types, named by appending "List" to the name of their
    element type, like in generated C.

  - The enumeration types implicitly defined by simple union types,
    named by appending "Kind" to the name of their simple union type,
    like in generated C.

  - Types that don't occur in generated C.  Their names start with ':'
    so they don't clash with the user's names.

* All type references are by name.

* The struct and union types are generalized into an object type.

* Base types are flattened.

* Commands take a single argument and return a single result.

  Dictionary argument or list result is an implicit type definition.

  The empty object type is used when a command takes no arguments or
  produces no results.

  The argument is always of object type, but the introspection schema
  doesn't reflect that.

  The 'gen': false directive is omitted as implementation detail.

  The 'success-response' directive is omitted as well for now, even
  though it's not an implementation detail, because it's not used by
  QMP.

* Events carry a single data value.

  Implicit type definition and empty object type use, just like for
  commands.

  The value is of object type, but the introspection schema doesn't
  reflect that.

* Types not used by commands or events are omitted.

  Indirect use counts as use.

* Optional members have a default, which can only be null right now

  Instead of a mandatory "optional" flag, we have an optional default.
  No default means mandatory, default null means optional without
  default value.  Non-null is available for optional with default
  (possible future extension).

* Clients should *not* look up types by name, because type names are
  not ABI.  Look up the command or event you're interested in, then
  follow the references.

  TODO Should we hide the type names to eliminate the temptation?

New generator scripts/qapi-introspect.py computes an introspection
value for its input, and generates a C variable holding it.

It can generate awfully long lines.  Marked TODO.

A new test-qmp-input-visitor test case feeds its result for both
tests/qapi-schema/qapi-schema-test.json and qapi-schema.json to a
QmpInputVisitor to verify it actually conforms to the schema.

New QMP command query-qmp-schema takes its return value from that
variable.  Its reply is some 85KiBytes for me right now.

If this turns out to be too much, we have a couple of options:

* We can use shorter names in the JSON.  Not the QMP style.

* Optionally return the sub-schema for commands and events given as
  arguments.

  Right now qmp_query_schema() sends the string literal computed by
  qmp-introspect.py.  To compute sub-schema at run time, we'd have to
  duplicate parts of qapi-introspect.py in C.  Unattractive.

* Let clients cache the output of query-qmp-schema.

  It changes only on QEMU upgrades, i.e. rarely.  Provide a command
  query-qmp-schema-hash.  Clients can have a cache indexed by hash,
  and re-query the schema only when they don't have it cached.  Even
  simpler: put the hash in the QMP greeting.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-21 09:56:49 +02:00
Markus Armbruster
156402e504 tests/qapi-schema: Convert test harness to QAPISchemaVisitor
The old code prints the result of parsing (list of expression
dictionaries), and partial results of semantic analysis (list of enum
dictionaries, list of struct dictionaries).

The new code prints a trace of a schema visit, i.e. what the back-ends
are going to use.  Built-in and array types are omitted, because
they're boring.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-21 09:32:50 +02:00
Lluís Vilanova
a719a27c82 qapi: Add a primitive to include other files from a QAPI schema file
The primitive uses JSON syntax, and include paths are relative to the file using the directive:

  { 'include': 'path/to/file.json' }

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-08 14:19:58 -04:00