Managing store's trees.
Tree provides immutable, in-memory partial mirror of the store, with lazy reads and delayed writes.
Trees are like staging area in Git: they are immutable temporary non-persistent areas (they disappear if the host crash), held in memory for efficiency, where reads are done lazily and writes are done only when needed on commit: if you modify a key twice, only the last change will be written to the store when you commit.
val empty : treeempty is the empty tree. The empty tree does not have associated backend configuration values, as they can perform in-memory operation, independently of any given backend.
of_contents c is the subtree built from the contents c.
kind t k is the type of s in t. It could either be a tree node or some file contents. It is None if k is not present in t.
diff x y is the difference of contents between x and y.
type 'a or_error = ('a, [ `Dangling_hash of hash ]) Stdlib.resultOperations on lazy nodes can fail if the underlying store does not contain the expected hash.
module Contents : sig ... endOperations on lazy tree contents.
find_all t k is Some (b, m) if k is associated to the contents b and metadata m in t and None if k is not present in t.
find is similar to find_all but it discards metadata.
Same as find_all but raise Invalid_arg if k is not present in t.
list t key is the list of files and sub-nodes stored under k in t. The result order is not specified but is stable.
offset and length are used for pagination.
add t k c is the tree where the key k is bound to the contents c but is similar to t for other bindings.
val update :
tree ->
key ->
?metadata:metadata ->
(contents option -> contents option) ->
tree Lwt.tupdate t k f is the tree t' that is the same as t for all keys except k, and whose binding for k is determined by f (find t k).
If k refers to an internal node of t, f is called with None to determine the value with which to replace it.
remove t k is the tree where k bindings has been removed but is similar to t for other bindings.
find_tree t k is Some v if k is associated to v in t. It is None if k is not present in t.
get_tree t k is v if k is associated to v in t. Raise Invalid_arg if k is not present in t.
add_tree t k v is the tree where the key k is bound to the tree v but is similar to t for other bindings
update_tree t k f is the tree t' that is the same as t for all subtrees except under k, and whose subtree at k is determined by f (find_tree t k).
val empty_marks : unit -> marksempty_marks () is an empty collection of marks.
The type for fold's force parameter. `True forces the fold to read the objects of the lazy nodes. `False f is applying f on every lazy node instead. `And_clear is like `True but also eagerly empty the Tree caches when traversing sub-nodes.
The type for fold's uniq parameters. `False folds over all the nodes. `True does not recurse on nodes already seen. `Marks m uses the collection of marks m to store the cache of keys: the fold will modify m. This can be used for incremental folds.
The type for fold depths.
Eq d folds over nodes and contents of depth exactly d.Lt d folds over nodes and contents of depth strictly less than d.Gt d folds over nodes and contents of depth strictly more than d.Le d is Eq d and Lt d. Ge d is Eq d and Gt d.
val fold :
?force:'a force ->
?uniq:uniq ->
?pre:'a node_fn ->
?post:'a node_fn ->
?depth:depth ->
?contents:(key -> contents -> 'a -> 'a Lwt.t) ->
?node:(key -> node -> 'a -> 'a Lwt.t) ->
tree ->
'a ->
'a Lwt.tfold f t acc folds f over t's leafs.
For every node n, ui n is a leaf node, call f path n. Otherwise:
pre path n. By default pre is the identity;fold on each children, in lexicographic order;post path n; By default post is the identity.See force for details about the force parameters. By default it is `And_clear.
See uniq for details about the uniq parameters. By default it is `False.
The fold depth is controlled by the depth parameter.
type stats = {nodes : int;Number of node.
*)leafs : int;Number of leafs.
*)skips : int;Number of lazy nodes.
*)depth : int;Maximal depth.
*)width : int;Maximal width.
*)}The type for tree stats.
stats ~force t are t's statistics. If force is true, this will force the reading of lazy nodes. By default it is false.
The type for concrete trees.
to_concrete t is the concrete tree equivalent of the subtree t.
val clear : ?depth:int -> tree -> unitclear ?depth t clears all caches in the tree t for subtrees with a depth higher than depth. If depth is not set, all of the subtrees are cleared.
val counters : unit -> countersval inspect : tree -> [ `Contents | `Node of [ `Map | `Hash | `Value ] ]of_hash r h is the the tree object in r having h as hash, or None is no such tree object exists.