|The abstract representation of a Tree and useful abstract utilities to
Abstraction of a filesystem tree.
Please note that the Tree returned by the respective read operations will
have TreeStub items in it. To obtain a Tree without such stubs, call
expand on it, eg.:
tree <- readDarcsPristine "." >>= expand
When a Tree is expanded, it becomes final. All stubs are forced and the
Tree can be traversed purely. Access to actual file contents stays in IO
A Tree may have a Hash associated with it. A pair of Tree's is identical
whenever their hashes are (the reverse need not hold, since not all Trees
come equipped with a hash).
|Unfolding stubbed (lazy) Trees.
|By default, Tree obtained by a read function is stubbed: it will
contain Stub items that need to be executed in order to access the
respective subtrees. expand will produce an unstubbed Tree.
|Unfold a stubbed Tree into a one with no stubs in it. You might want to
filter the tree before expanding to save IO.
|Unfold a path in a (stubbed) Tree, such that the leaf node of the path is
reachable without crossing any stubs.
|Tree access and lookup.
|List all contents of a Tree.
|Get hash of a Tree. This is guaranteed to uniquely
identify the Tree (including any blob content), as far as
cryptographic hashes are concerned. Sha256 is recommended.
|Look up a Tree item (an immediate subtree or blob).
|Find a TreeItem by its path. Gives Nothing if the path is invalid.
|Find a Blob by its path. Gives Nothing if the path is invalid, or does
not point to a Blob.
|Find a Tree by its path. Gives Nothing if the path is invalid, or does
not point to a Tree.
|Get a hash of a TreeItem. May be Nothing.
|For every pair of corresponding blobs from the two supplied trees,
evaluate the supplied function and accumulate the results in a list. Hint:
to get IO actions through, just use sequence on the resulting list.
NB. This won't expand any stubs.
|For each file in each of the two supplied trees, evaluate the supplied
function (supplying the corresponding file from the other tree, or Nothing)
and accumulate the results in a list. Hint: to get IO actions through, just
use sequence on the resulting list. NB. This won't expand any stubs.
|Cautiously extracts differing subtrees from a pair of Trees. It will never
do any unneccessary expanding. Tree hashes are used to cut the comparison as
high up the Tree branches as possible. The result is a pair of trees that do
not share any identical subtrees. They are derived from the first and second
parameters respectively and they are always fully expanded. It might be
advantageous to feed the result into zipFiles or zipTrees.
|Read a Blob into a Lazy ByteString. Might be backed by an mmap, use with
|When implementing a Tree that has complex expanding
semantics, the finish IO action lets you do arbitrary IO
transform on the Tree after it is expanded but before it is
given to the user by expand. (Used to implement Index
|Given a predicate of the form AnchoredPath -> TreeItem -> Bool, and a
Tree, produce a Tree that only has items for which the predicate returned
True. The tree might contain stubs. When expanded, these will be subject to
filtering as well.
|Given two Trees, a guide and a tree, produces a new Tree that is a
identical to tree, but only has those items that are present in both
tree and guide. The guide Tree may not contain any stubs.
|Produced by Haddock version 2.4.2|