Expose some weaknesses in the generator: we don't always forbid
the generation of structs that contain multiple members that map
to the same C or QMP name.  This has already been marked FIXME in
qapi.py in commit d90675fa, but having more tests will make sure
future patches produce desired behavior; and updating existing
patches to better document things doesn't hurt, either.  Some of
these collisions are already caught in the old-style parser
checks, but ultimately we want all collisions to be caught in the
new-style QAPISchema*.check() methods.

This patch focuses on C struct members, and does not consider
collisions between commands and events (affecting C function
names), or even collisions between generated C type names with
user type names (for things like automatic FOOList struct
representing array types or FOOKind for an implicit enum).

There are two types of struct collisions we want to catch:
 1) Collision between two keys in a JSON object. qapi.py prevents
    that within a single struct (see test duplicate-key), but it is
    possible to have collisions between a type's members and its
    base type's members (existing tests struct-base-clash,
    struct-base-clash-deep), and its flat union variant members
    (renamed test flat-union-clash-member).
 2) Collision between two members of the C struct that is generated
    for a given QAPI type:
    a) Multiple QAPI names map to the same C name (new test
       args-name-clash)
    b) A QAPI name maps to a C name that is used for another purpose
       (new tests flat-union-clash-branch, struct-base-clash-base,
       union-clash-data). We already fixed some such cases in commit
       0f61af3e and 1e6c1616, but more remain.
    c) Two C names generated for other purposes clash
       (updated test alternate-clash, new test union-clash-branches,
       union-clash-type, flat-union-clash-type)

Ultimately, if we need to have a flat union where a tag value
clashes with a base member name, we could change the generator to
name the union (using 'foo.u.value' rather than 'foo.value') or
otherwise munge the C name corresponding to tag values.  But
unless such a need arises, it will probably be easier to just
forbid these collisions.

Some of these negative tests will be deleted later, and positive
tests added to qapi-schema-test.json in their place, when the
generator code is reworked to avoid particular code generation
collisions in class 2).

[Note that viewing this patch with git rename detection enabled
may see some confusion due to renaming some tests while adding
others, but where the content is similar enough that git picks
the wrong pre- and post-patch files to associate]
Signed-off-by: NEric Blake <eblake@redhat.com>
Message-Id: <1443565276-4535-6-git-send-email-eblake@redhat.com>
[Improve commit message and comments a bit, drop an unrelated test]
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Use of '"...%s" % include' to print non-strings can lead to
ugly messages, such as this (if the .json change is applied
without the qapi.py change):
 Expected a file name (string), got: OrderedDict()

Better is to just omit the actual non-string value in the
message.
Signed-off-by: NEric Blake <eblake@redhat.com>
Message-Id: <1443565276-4535-3-git-send-email-eblake@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

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: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

'gen': false needs to stay for now, because netdev_add is still using
it.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>
Message-Id: <1442401589-24189-25-git-send-email-armbru@redhat.com>

It's first class, because unlike '**', it actually works, i.e. doesn't
require 'gen': false.

'**' will go away next.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>

Fixes events whose data is struct with base to include the struct's
base members.  Test case is qapi-schema-test.json's event
__org.qemu_x-command:

    { 'event': '__ORG.QEMU_X-EVENT', 'data': '__org.qemu_x-Struct' }

    { 'struct': '__org.qemu_x-Struct', 'base': '__org.qemu_x-Base',
      'data': { '__org.qemu_x-member2': 'str' } }

    { 'struct': '__org.qemu_x-Base',
      'data': { '__org.qemu_x-member1': '__org.qemu_x-Enum' } }

Patch's effect on generated qapi_event_send___org_qemu_x_event():

    -void qapi_event_send___org_qemu_x_event(const char *__org_qemu_x_member2,
    +void qapi_event_send___org_qemu_x_event(__org_qemu_x_Enum __org_qemu_x_member1,
    +                                        const char *__org_qemu_x_member2,
                                             Error **errp)
     {
         QDict *qmp;
    @@ -224,6 +225,10 @@ void qapi_event_send___org_qemu_x_event(
             goto clean;
         }

    +    visit_type___org_qemu_x_Enum(v, &__org_qemu_x_member1, "__org.qemu_x-member1", &local_err);
    +    if (local_err) {
    +        goto clean;
    +    }
         visit_type_str(v, (char **)&__org_qemu_x_member2, "__org.qemu_x-member2", &local_err);
         if (local_err) {
             goto clean;

Code is generated in a different order now, but that doesn't matter.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>

Fixes flat unions to visit the base's base members (the previous
commit merely added them to the struct).  Same test case.

Patch's effect on visit_type_UserDefFlatUnion():

     static void visit_type_UserDefFlatUnion_fields(Visitor *m, UserDefFlatUnion **obj, Error **errp)
     {
         Error *err = NULL;

    +    visit_type_int(m, &(*obj)->integer, "integer", &err);
    +    if (err) {
    +        goto out;
    +    }
         visit_type_str(m, &(*obj)->string, "string", &err);
         if (err) {
             goto out;

Test cases updated for the bug fix.

Fixes alternates to generate a visitor for their implicit enumeration
type.  None of them are currently used, obviously.  Example:
block-core.json's BlockdevRef now generates
visit_type_BlockdevRefKind().

Code is generated in a different order now, and therefore has got a
few new forward declarations.  Doesn't matter.

The guard QAPI_VISIT_BUILTIN_VISITOR_DECL is renamed to
QAPI_VISIT_BUILTIN.

The previous commit's two ugly special cases exist here, too.  Mark
both TODO.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Fixes flat unions to get the base's base members.  Test case is from
commit 2fc00432, in qapi-schema-test.json:

    { 'union': 'UserDefFlatUnion',
      'base': 'UserDefUnionBase',
      'discriminator': 'enum1',
      'data': { 'value1' : 'UserDefA',
                'value2' : 'UserDefB',
                'value3' : 'UserDefB' } }

    { 'struct': 'UserDefUnionBase',
      'base': 'UserDefZero',
      'data': { 'string': 'str', 'enum1': 'EnumOne' } }

    { 'struct': 'UserDefZero',
      'data': { 'integer': 'int' } }

Patch's effect on UserDefFlatUnion:

     struct UserDefFlatUnion {
         /* Members inherited from UserDefUnionBase: */
    +    int64_t integer;
         char *string;
         EnumOne enum1;
         /* Own members: */
         union { /* union tag is @enum1 */
             void *data;
             UserDefA *value1;
             UserDefB *value2;
             UserDefB *value3;
         };
     };

Flat union visitors remain broken.  They'll be fixed next.

Code is generated in a different order now, but that doesn't matter.

The two guards QAPI_TYPES_BUILTIN_STRUCT_DECL and
QAPI_TYPES_BUILTIN_CLEANUP_DECL are replaced by just
QAPI_TYPES_BUILTIN.

Two ugly special cases for simple unions now stand out like sore
thumbs:

1. The type tag is named 'type' everywhere, except in generated C,
   where it's 'kind'.

2. QAPISchema lowers simple unions to semantically equivalent flat
   unions.  However, the C generated for a simple unions differs from
   the C generated for its equivalent flat union, and we therefore
   need special code to preserve that pointless difference for now.

Mark both TODO.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

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: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The QAPI code generators work with a syntax tree (nested dictionaries)
plus a few symbol tables (also dictionaries) on the side.

They have clearly outgrown these simple data structures.  There's lots
of rummaging around in dictionaries, and information is recomputed on
the fly.  For the work I'm going to do, I want more clearly defined
and more convenient interfaces.

Going forward, I also want less coupling between the back-ends and the
syntax tree, to make messing with the syntax easier.

Create a bunch of classes to represent QAPI schemata.

Have the QAPISchema initializer call the parser, then walk the syntax
tree to create the new internal representation, and finally perform
semantic analysis.

Shortcut: the semantic analysis still relies on existing check_exprs()
to do the actual semantic checking.  All this code needs to move into
the classes.  Mark as TODO.

Simple unions are lowered to flat unions.  Flat unions and structs are
represented as a more general object type.

Catching name collisions in generated code would be nice.  Mark as
TODO.

We generate array types eagerly, even though most of them aren't used.
Mark as TODO.

Nothing uses the new intermediate representation just yet, thus no
change to generated files.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NDaniel P. Berrange <berrange@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The camel_to_upper() method applies some heuristics to turn
a mixed case type name into an all-uppercase name. This is
used for example, to generate enum constant name prefixes.

The heuristics don't also generate a satisfactory name
though. eg

  { 'enum': 'QCryptoTLSCredsEndpoint',
    'data': ['client', 'server']}

Results in Q_CRYPTOTLS_CREDS_ENDPOINT_CLIENT. This has
an undesirable _ after the initial Q and is missing an
_ between the CRYPTO & TLS strings.

Rather than try to add more and more heuristics to try
to cope with this, simply allow the QAPI schema to
specify the desired enum constant prefix explicitly.

eg

  { 'enum': 'QCryptoTLSCredsEndpoint',
    'prefix': 'QCRYPTO_TLS_CREDS_ENDPOINT',
    'data': ['client', 'server']}

Now gives the QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT name.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

check_type() first checks and peels off the array type, then checks
the element type.  For two out of four error messages, it takes pains
to report errors for "array of T" instead of just T.  Odd.  Let's
examine the errors.

* Unknown element type, e.g.
  tests/qapi-schema/args-array-unknown.json:

      Member 'array' of 'data' for command 'oops' uses unknown type
      'array of NoSuchType'

  To make sense of this, you need to know that 'array of NoSuchType'
  refers to '[NoSuchType]'.  Easy enough.  However, simply reporting

      Member 'array' of 'data' for command 'oops' uses unknown type
      'NoSuchType'

  is at least as easy to understand.

* Element type's meta-type is inadmissible, e.g.
  tests/qapi-schema/returns-whitelist.json:

      'returns' for command 'no-way-this-will-get-whitelisted' cannot
      use built-in type 'array of int'

  'array of int' is technically not a built-in type, but that's
  pedantry.  However, simply reporting

      'returns' for command 'no-way-this-will-get-whitelisted' cannot
      use built-in type 'int'

  avoids the issue, and is at least as easy to understand.

* The remaining two errors are unreachable, because the array checking
  ensures that value is a string.

Thus, reporting some errors for "array of T" instead of just T works,
but doesn't really improve things.  Drop it.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Fixes the errors demonstrated by the previous commit.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

We always report "should be a dictionary" then.  This is misleading:
when allow_dict, it can be a dictionary or a type name string, else it
can only be a type name.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Syntax error coverage should now be complete.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The first check ensures the second one can't trigger.  Drop the first
one, because the second one is in a more logical place, and emits a
nicer error message.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Reproducer: with

    { 'command': 'user_def_cmd4', 'returns': { 'a': 'int' } }

added to qapi-schema-test.json, qapi-commands.py dies when it tries to
generate the command handler function

    Traceback (most recent call last):
      File "/work/armbru/qemu/scripts/qapi-commands.py", line 359, in <module>
        ret = generate_command_decl(cmd['command'], arglist, ret_type) + "\n"
      File "/work/armbru/qemu/scripts/qapi-commands.py", line 29, in generate_command_decl
        ret_type=c_type(ret_type), name=c_name(name),
      File "/work/armbru/qemu/scripts/qapi.py", line 927, in c_type
        assert isinstance(value, str) and value != ""
    AssertionError

because the return type doesn't exist.

Simply outlaw this usage, and drop or dumb down test cases accordingly.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

A command's or event's 'data' must be a struct type, given either as a
dictionary, or as struct type name.

Commit dd883c6f tightened the checking there, but not enough: we still
accept 'union'.  Fix to reject it.

We may want to support union types there, but we'll have to extend
qapi-commands.py and qapi-events.py for it.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

A command's 'data' must be a struct type, given either as a
dictionary, or as struct type name.

Existing test case data-int.json covers simple type 'int'.  Add test
cases for type names referring to union and alternate types.

The latter is caught (good), but the former is not (bug).

Events have the same problem, but since they get checked by the same
code, we don't bother to duplicate the tests.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Since every schema entity has 'data', the data- prefix conveys no
information.  These tests actually exercise commands.  Only commands
have arguments, so change the prefix to to args-.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Test case added in commit 2fc00432, and messed up in commit 5223070c.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

When event FOO's 'data' is a struct with a base, we consider only the
struct's direct members, and ignore its base.  The generated
qapi_event_send_foo() doesn't take arguments for base members.

No such events currently exist in the QMP schema.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

We generate a declaration, but no definition.

The QMP schema has two: Qcow2OverlapChecks and BlockdevRef.  Neither
visit_type_Qcow2OverlapChecksKind() nor visit_type_BlockdevRefKind()
is actually used.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The visit_type_implicit_FOO() are generated on demand, right before
their first use.  Used by visit_type_STRUCT_fields() when STRUCT has
base FOO, and by visit_type_UNION() when flat UNION has member a FOO.

If the schema defines FOO after its first use as struct base or flat
union member, visit_type_implicit_FOO() calls
visit_type_implicit_FOO() before its definition, which doesn't
compile.

Rearrange qapi-schema-test.json to demonstrate the bug.

Fix by generating the necessary forward declaration.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

The new test demonstrates another generator crash.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

We print the name as it appears in the include expression.  Tools
processing error messages want it relative to the working directory.
Make it so.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>

Enhance the testsuite to cover downstream events and commands.
Events worked without more tweaks, but commands needed a few final
updates in the generator to mangle names in the appropriate places.
In making those tweaks, it was easier to drop type_visitor() and
inline its actions instead.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Enhance the testsuite to cover downstream alternates, including
whether the branch name or type is downstream.  Update the
generator to mangle alternate names in the appropriate places.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Enhance the testsuite to cover downstream flat unions, including
the base type, discriminator name and type, and branch name and
type.  Update the generator to mangle the union names in the
appropriate places.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Enhance the testsuite to cover downstream simple unions, including
when a union branch is a downstream name.  Update the generator to
mangle the union names in the appropriate places.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Enhance the testsuite to cover downstream structs, including struct
members and base structs.  Update the generator to mangle the
struct names in the appropriate places.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Enhance the testsuite to cover a downstream enum type and enum
string.  Update the generator to mangle the enum name in the
appropriate places.
Signed-off-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Our type inheritance for both 'struct' and for flat 'union' merges
key/value pairs from the base class with those from the type in
question.  Although the C code currently boxes things so that there
is a distinction between which member is referred to, the QMP wire
format does not allow passing a key more than once in a single
object.  Besides, if we ever change the generated C code to not be
quite so boxy, we'd want to avoid duplicate member names there,
too.

Fix a testsuite entry added in an earlier patch, as well as adding
a couple more tests to ensure we have appropriate coverage.  Ensure
that collisions are detected, regardless of whether there is a
difference in opinion on whether the member name is optional.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

The handling of \ inside QAPI strings was less than ideal, and
really only worked JSON's \/, \\, \", and our extension of \'
(an obvious extension, when you realize we use '' instead of ""
for strings).  For other things, like '\n', it resulted in a
literal 'n' instead of a newline.

Of course, at the moment, we really have no use for escaped
characters, as QAPI has to map to C identifiers, and we currently
support ASCII only for that.  But down the road, we may add
support for default values for string parameters to a command
or struct; if that happens, it would be nice to correctly support
all JSON escape sequences, such as \n or \uXXXX.  This gets us
closer, by supporting Unicode escapes in the ASCII range.

Since JSON does not require \OCTAL or \xXX escapes, and our QMP
implementation does not understand them either, I intentionally
reject it here, but it would be an easy addition if we desired it.
Likewise, intentionally refusing the NUL byte means we don't have
to worry about C strings being shorter than the qapi input.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

A future patch will be using a 'name':{dictionary} entry in the
QAPI schema to specify a default value for an optional argument
(see previous commit messages for more details why); but existing
use of inline nested structs conflicts with that goal. Now that
all commands have been changed to avoid inline nested structs,
nuke support for them, and turn it into a hard error. Update the
testsuite to reflect tighter parsing rules.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

A future patch will be using a 'name':{dictionary} entry in the
QAPI schema to specify a default value for an optional argument;
but existing use of inline nested structs conflicts with that goal.

More precisely, a definition in the QAPI schema associates a name
with a set of properties:

Example 1: { 'struct': 'Foo', 'data': { MEMBERS... } }
associates the global name 'Foo' with properties (meta-type struct)
and MEMBERS...

Example 2: 'mumble': TYPE
within MEMBERS... above associates 'mumble' with properties (type
TYPE) and (optional false) within type Foo

The syntax of example 1 is extensible; if we need another property,
we add another name/value pair to the dictionary (such as
'base':TYPE).  The syntax of example 2 is not extensible, because
the right hand side can only be a type.

We have used name encoding to add a property: "'*mumble': 'int'"
associates 'mumble' with (type int) and (optional true).  Nice,
but doesn't scale.  So the solution is to change our existing uses
to be syntactic sugar to an extensible form:

   NAME: TYPE   --> NAME:  { 'type': TYPE, 'optional': false }
   *ONAME: TYPE --> ONAME: { 'type': TYPE, 'optional': true }

This patch fixes the testsuite to avoid inline nested types, by
breaking the nesting into explicit types; it means that the type
is now boxed instead of unboxed in C code, but makes no difference
on the wire (and if desired, a later patch could change the
generator to not do so much boxing in C).  When touching code to
add new allocations, also convert existing allocations to
consistently prefer typesafe g_new0 over g_malloc0 when a type
name is involved.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

In the testsuite, UserDefTwo and UserDefNested were identical
structs other than the member names.  Reduce code duplication by
having just one type, and choose names that also favor reuse.
This will also make it easier for a later patch to get rid of
inline nested types in QAPI.  When touching code related to
allocations, convert g_malloc0(sizeof(Type)) to the more typesafe
g_new0(Type, 1).

Ensure that 'make check-qapi-schema check-unit' still passes.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Referring to "type" as both a meta-type (built-in, enum, union,
alternate, or struct) and a specific type (the name that the
schema uses for declaring structs) is confusing.  Do the bulk of
the conversion to "struct" in qapi schema, with a fairly
mechanical:

for f in `find -name '*.json'; do sed -i "s/'type'/'struct'/"; done

followed by manually filtering out the places where we have a
'type' embedded in 'data'.  Then tweak a couple of tests whose
output changes slightly due to longer lines.

I also verified that the generated files for QMP and QGA (such
as qmp-commands.h) are the same before and after, as assurance
that I didn't leave in any accidental member name changes.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>

Referring to "type" as both a meta-type (built-in, enum, union,
alternate, or struct) and a specific type (the name that the
schema uses for declaring structs) is confusing.  The confusion
is only made worse by the fact that the generator mostly already
refers to struct even when dealing with expr['type'].  This
commit changes the generator to consistently refer to it as
struct everywhere, plus a single back-compat tweak that allows
accepting the existing .json files as-is, so that the meat of
this change is separate from the mindless churn of that change.

Fix the testsuite fallout for error messages that change, and
in some cases, become more legible.  Improve comments to better
match our intentions where a struct (rather than any complex
type) is required.  Note that in some cases, an error message
now refers to 'struct' while the schema still refers to 'type';
that will be cleaned up in the later commit to the schema.
Signed-off-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>