Both containerd and graphdriver image service use the same code to
create the cache - they only supply their own `cacheAdaptor` struct.
Extract the shared code to `cache.New`.
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
Move image store backend specific code out of the cache code and move it
to a separate interface to allow using the same cache code with
containerd image store.
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
The compatibility depends on whether `hyperv` or `process` container
isolation is used.
This fixes cache not being used when building images based on older
Windows versions on a newer Windows host.
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
Restrict cache candidates only to images that were built locally.
This doesn't affect builds using `--cache-from`.
Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
The most notable change here is that the OCI's type uses a pointer for `Created`, which we probably should've been too, so most of these changes are accounting for that (and embedding our `Equal` implementation in the one single place it was used).
Signed-off-by: Tianon Gravi <admwiggin@gmail.com>
