[libvirt] [PATCH v4 0/12] migration: support all toURI and proto combos

Current implementation of 'toURI' migration interfaces does not support all combinations of interface versions and protocol versions. For example 'toURI2' with p2p flag will not migrate if driver supports only v3params proto. This is not convinient as drivers that starts to support migration have to manually support older versions of protocol. I guess this should be done in one place, namely here. Another issue is that there are a lot of code duplication in implementation of toURI interfaces and it is not obvious from code how are they related. This implementation uses extensible parameters as intermediate parameters representation. This is possible as interfaces are done backward compatible in terms of parameters and later versions supports all parameters of former versions. = Changes from version 3 * fix spellings * make error messages more specific as suggested * in 'migration: refactor: introduce params version of unmanaged': fix conversion for null values of explicit string params into virTypedParameterPtr. * squash 'migration: reuse parameters check in toURI2 and toURI3' into 'migration: introduce parameter checking function' * 'migration: refactor: one return in forURI family functions' is dropped as suggested src/libvirt-domain.c | 509 +++++++++++++++++++++++--------------------------- 1 files changed, 237 insertions(+), 272 deletions(-)