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package irmin
Commit Store
include Indexable.S
Read-only stores
Read-only stores are store where it is only possible to read existing values.
val mem : [> Perms.read ] t -> key -> bool Lwt.tmem t k is true iff k is present in t.
val find : [> Perms.read ] t -> key -> value option Lwt.tfind t k is Some v if k is associated to v in t and None is k is not present in t.
close t frees up all the resources associated with t. Any operations run on a closed handle will raise Closed.
val add : [> Perms.write ] t -> value -> key Lwt.tWrite the contents of a value to the store, and obtain its key.
Same as add but allows specifying the value's hash directly. The backend might choose to discard that hash and/or can be corrupt if the hash is not consistent.
val index : [> Perms.read ] t -> hash -> key option Lwt.tIndexing maps the hash of a value to a corresponding key of that value in the store. For stores that are addressed by hashes directly, this is typically fun _t h -> Lwt.return (Key.of_hash h); for stores with more complex addressing schemes, index may attempt a lookup operation in the store.
In general, indexing is best-effort and reveals no information about the membership of the value in the store. In particular:
index t hash = Some keydoesn't guaranteemem t key: the value with hashhashmay still be absent from the store;
index t hash = Nonedoesn't guarantee that there is nokeysuch thatmem t keyandKey.to_hash key = hash: the value may still be present in the store under a key that is not indexed.
val batch :
Perms.read t ->
([ Perms.read | Perms.write ] t -> 'a Lwt.t) ->
'a Lwt.tbatch t f applies the writes in f in a separate batch. The exact guarantees depend on the implementation.
module Val : sig ... endVal provides functions for commit values.
module Node : Node.Store with type key = Val.node_keyNode is the underlying node store.
val merge : [> Perms.read_write ] t -> info:Info.f -> key option Merge.tmerge is the 3-way merge function for commit keys.
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