On 3/14/19 9:43 AM, Cole Robinson wrote:
Right now in qemuxml2argv we have a proliferation of DO_*TEST* macros. They essentially fill in data in the testInfo struct and invoke the test function.
There's several bits of data that we want to specify for a small subset of tests: flags, parseFlags, migrateFrom/migrateFd, gic. The base macros need to handle these in their argument lists, and we provide many convenience macros that fill in default values for the less common parameters. Any time we want to add a new bit of data though, the base macros are extended, and every caller of those needs to be adjusted, and we are faced with the question of whether to extend the combinatorial explosion of convenience macros which have only a subset of options exposed.
This series adds a testInfoSetArgs which uses va_args to make these mandatory parameters optional. The general format is:
DO_TEST_FULL(... ARG_FOO, foovalue, ARG_BAR, barvalue, ...)
Specifically, one of the migrate tests went from:
DO_TEST_FULL("restore-v2", "exec:cat", 7, 0, 0, GIC_NONE, NONE);
to:
DO_TEST_FULL("restore-v2", ARG_MIGRATE_FROM, "exec:cat", ARG_MIGRATE_FD, 7, ARG_QEMU_CAPS, NONE);
Umm, what's your sentinel value here? It is undefined behavior to call va_arg more times than there are arguments present, but without some sort of sentinel, you don't know when to stop calling va_arg. The overall idea is nice, but I think you need an ARG_END sentinel. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org