From bceae7697ff1711675c26f715b945737bc6849ae Mon Sep 17 00:00:00 2001 From: Wenchao Xia Date: Thu, 6 Mar 2014 17:08:56 -0800 Subject: qapi script: support enum type as discriminator in union By default, any union will automatically generate a enum type as "[UnionName]Kind" in C code, and it is duplicated when the discriminator is specified as a pre-defined enum type in schema. After this patch, the pre-defined enum type will be really used as the switch case condition in generated C code, if discriminator is an enum field. Signed-off-by: Wenchao Xia Reviewed-by: Markus Armbruster Signed-off-by: Luiz Capitulino --- docs/qapi-code-gen.txt | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'docs') diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt index 0728f36c65..a2e7921601 100644 --- a/docs/qapi-code-gen.txt +++ b/docs/qapi-code-gen.txt @@ -123,11 +123,15 @@ And it looks like this on the wire: Flat union types avoid the nesting on the wire. They are used whenever a specific field of the base type is declared as the discriminator ('type' is -then no longer generated). The discriminator must always be a string field. +then no longer generated). The discriminator can be a string field or a +predefined enum field. If it is a string field, a hidden enum type will be +generated as "[UNION_NAME]Kind". If it is an enum field, a compile time check +will be done to verify the correctness. It is recommended to use an enum field. The above example can then be modified as follows: + { 'enum': 'BlockdevDriver', 'data': [ 'raw', 'qcow2' ] } { 'type': 'BlockdevCommonOptions', - 'data': { 'driver': 'str', 'readonly': 'bool' } } + 'data': { 'driver': 'BlockdevDriver', 'readonly': 'bool' } } { 'union': 'BlockdevOptions', 'base': 'BlockdevCommonOptions', 'discriminator': 'driver', -- cgit v1.2.1