Implicitly the query depth is limited by the length of the QAPI schema
query, but 'alternate' and 'array' QAPI meta-types don't consume a part
of the query string thus a loop on such types would get our traversal
code stuck in an infinite loop. Prevent this from happening by limiting
the nesting depth to 1000.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NDaniel P. Berrangé <berrange@redhat.com>

Starting from version 4.1 qemu allows reporting 'features' for a given
QAPI type object. This allows reporting support of fixes and additions
which are otherwise invisible in the QAPI schema.

Implement a possibility to query 'features' in the QAPI query strings.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJiri Denemark <jdenemar@redhat.com>

Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Prepare section for boolean queries and make the typed query section
more clear.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

We treated broken schema as failure to look up given query. Treat it as
a separate error instead. It is unlikely to happen though.

Also prepare for possibility of user errors if query components which
can't be queired deeper have following components.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Introduce an array of callbacks for given 'meta-type' of the QAPI schema
structure rather than using code to select it. This will simplify
extension for the other meta-types which are not handled yet.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Rather than modifying the context struct add a helpers that does this.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Now that 'query' is no longer an argument we can reuse it.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Create a context data type for the QAPI path rather than passing an
increasing number of arguments.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

virQEMUQAPISchemaTypeFromObject and virQEMUQAPISchemaTypeFromObject
can be very easily folded into virQEMUQAPISchemaTraverseObject removing
the need for the helpers.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Simplify virQEMUQAPISchemaTraverse by separating out the necessary
operations for given 'meta-type' into separate functions.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Return 1 if the schema entry was found optionally returning it rather
than depending on the returned object.

Some callers don't care which schema object belongs to the query, but
rather only want to know whether it exists. Additionally this will allow
introducing boolean queries for checking if enum values exist.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

To allow for boolean query string, let's return the queried schema entry
via argument rather than a return value.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

The return statement after the infinite loop without a break is there to
appease the compiler. Make it return NULL as it would be a failure if
control flow reaches that point.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

Add a new modifier character '*' which will select given schema entry
only when it is optional (denoted by the presence of the 'default' key).
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>

Split it into a function that returns the whole schema entry so that we
can do additional checks and a helper getting the type string from the
schema entry.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>

Introduce a few variables so that we can easily access the modifier
character and also don't have to do pointer arithmetic when selecting
the schema entries. This will simplify adding of new modifier
characters.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>

virQEMUQAPISchemaTraverse would return previous-to-last queried item on
a query. It would not be a problem if checking if the given path exists
since error reporting works properly but if the caller is interested in
the result, it would be wrong.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

The JSON array was processed to the hash table used by the query apis in
the monitor code. Move it to a new helper in qemu_qapi.c.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

Change the prefix of the functions to 'virQEMUQapi' and rename the two
public APIs so that the verb is put last.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>

Extract the code into qemu_qapi.c/h so that we separate it from various
parts of the code.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>