The TreeNodeIterator decodes nodes while iterating over a tree blob.
This should reduce peak memory usage as now only the serialized tree
blob and a single node have to alive at the same time. Using the
iterator has implications for the error handling however. Now it is
necessary that all loops that iterate through a tree check for errors
before using the node returned by the iterator.
The other change is that it is no longer possible to iterate over a tree
multiple times. Instead it must be loaded a second time. This only
affects the tree rewriting code.
wg.Go() may not be called after wg.Wait(). This prevents connecting two
errgroups such that the errors are propagated between them if the child
errgroup dynamically starts goroutines. Instead use just a single errgroup,
and sequence the shutdown using a sync.WaitGroup. This is far simpler
and does not require any "clever" tricks.
The new method combines both step into a single wrapper function. Thus
it ensures that both are always called in pairs. As an additional
benefit this slightly reduces the boilerplate to upload blobs.
this could crash in two cases:
- if a directory is deleted between restic stating it and trying to list
its directory content.
- when restic tries to list the parent directory of a backup target, but
the parent directory has been deleted.
return an error in this case instead.
This adds proper support for filenames that include directories. For
example, `/foo/bar` would result in an error when trying to open `/foo`.
The directory tree is now build upfront. This ensures let's the
directory tree construction be handled only once. All accessors then
only have to look up the constructed directory entries.
Those methods now only allow modifying snapshots. Internal data types
used by the repository are now read-only. The repository-internal code
can bypass the restrictions by wrapping the repository in an
`internalRepository` type.
The restriction itself is implemented by using a new datatype
WriteableFileType in the SaveUnpacked and RemoveUnpacked methods. This
statically ensures that code cannot bypass the access restrictions.
The test changes are somewhat noisy as some of them modify repository
internals and therefore require some way to bypass the access
restrictions. This works by capturing an `internalRepository` or
`Backend` when creating the Repository using a test helper function.
Only the `Sys()` value from os.FileInfo is kept as field `sys` to
support Windows. The os.FileInfo removal ensures that for values like
`ModTime` that existed in both data structures there's no more confusion
which value is actually used.
The actual implementation still relies on file paths, but with the
abstraction layer in place, an FS implementation can ensure atomic file
accesses in the future.
Depending on parameters the paths in a snapshot do not directly
correspond to real paths on the filesystem. Therefore, reject funcs must
use the FS interface to work correctly.
