package octez-internal-libs
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dune-project
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sha256=ddfb5076eeb0b32ac21c1eed44e8fc86a6743ef18ab23fff02d36e365bb73d61
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doc/octez-internal-libs.irmin/Irmin/module-type-S/index.html
Module type Irmin.SSource
Irmin stores.
Irmin stores
Irmin stores are tree-like read-write stores with extended capabilities. They allow an application (or a collection of applications) to work with multiple local states, which can be forked and merged programmatically, without having to rely on a global state. In a way very similar to version control systems, Irmin local states are called branches.
There are two kinds of store in Irmin: the ones based on persistent named branches and the ones based temporary detached heads. These exist relative to a local, larger (and shared) store, and have some (shared) contents. This is exactly the same as usual version control systems, that the informed user can see as an implicit purely functional data-structure.
The type for Irmin repositories.
The type for Irmin stores.
The type for key steps.
The type for store keys. A key is a sequence of steps.
The type for store metadata.
The type for store contents.
The type for store nodes.
The type for store trees.
Type for `Commit identifiers. Similar to Git's commit SHA1s.
Type for persistent branch names. Branches usually share a common global namespace and it's the user's responsibility to avoid name clashes.
Type for store slices.
The type for commit info.
The type for errors associated with functions computing least common ancestors
The type for errors for Head.fast_forward.
empty repo is a temporary, empty store. Becomes a normal temporary store after the first update.
main r is a persistent store based on r's main branch. This operation is cheap, can be repeated multiple times.
of_branch r name is a persistent store based on the branch name. Similar to main, but use name instead of Irmin.Branch.S.main.
of_commit c is a temporary store, based on the commit c.
Temporary stores do not have stable names: instead they can be addressed using the hash of the current commit. Temporary stores are similar to Git's detached heads. In a temporary store, all the operations are performed relative to the current head and update operations can modify the current head: the current stores's head will automatically become the new head obtained after performing the update.
tree t is t's current tree. Contents is not allowed at the root of the tree.
status t is t's status. It can either be a branch, a commit or empty.
Reads
kind is Tree.kind applied to t's root tree.
mem_tree t is Tree.mem_tree applied to t's root tree.
find_all t is Tree.find_all applied to t's root tree.
get_all t is Tree.get_all applied on t's root tree.
find_tree t is Tree.find_tree applied to t's root tree.
id t k
Updates
The type for write errors.
- Merge conflict.
- Concurrent transactions are competing to get the current operation committed and too many attemps have been tried (livelock).
- A "test and set" operation has failed and the current value is
vinstead of the one we were waiting for.
val set :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
t ->
path ->
contents ->
(unit, write_error) result Lwt.tset t k ~info v sets k to the value v in t. Discard any previous results but ensure that no operation is lost in the history.
This function always uses Metadata.default as metadata. Use set_tree with `Contents (c, m) for different ones.
When clear is set (the default), the tree cache is emptied upon the function's completion, mirroring the effect of invoking Tree.clear.
The result is Error `Too_many_retries if the concurrent operations do not allow the operation to commit to the underlying storage layer (livelock).
val set_exn :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
t ->
path ->
contents ->
unit Lwt.tset_exn is like set but raise Failure _ instead of using a result type.
val set_tree :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
t ->
path ->
tree ->
(unit, write_error) result Lwt.tset_tree is like set but for trees.
val set_tree_exn :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
t ->
path ->
tree ->
unit Lwt.tset_tree is like set_exn but for trees.
val remove :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
t ->
path ->
(unit, write_error) result Lwt.tremove t ~info k remove any bindings to k in t.
The result is Error `Too_many_retries if the concurrent operations do not allow the operation to commit to the underlying storage layer (livelock).
val remove_exn :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
t ->
path ->
unit Lwt.tremove_exn is like remove but raise Failure _ instead of a using result type.
val test_and_set :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
t ->
path ->
test:contents option ->
set:contents option ->
(unit, write_error) result Lwt.ttest_and_set ~test ~set is like set but it atomically checks that the tree is test before modifying it to set.
This function always uses Metadata.default as metadata. Use test_and_set_tree with `Contents (c, m) for different ones.
The result is Error (`Test t) if the current tree is t instead of test.
The result is Error `Too_many_retries if the concurrent operations do not allow the operation to commit to the underlying storage layer (livelock).
val test_and_set_exn :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
t ->
path ->
test:contents option ->
set:contents option ->
unit Lwt.ttest_and_set_exn is like test_and_set but raise Failure _ instead of using a result type.
val test_and_set_tree :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
t ->
path ->
test:tree option ->
set:tree option ->
(unit, write_error) result Lwt.ttest_and_set_tree is like test_and_set but for trees.
val test_and_set_tree_exn :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
t ->
path ->
test:tree option ->
set:tree option ->
unit Lwt.ttest_and_set_tree_exn is like test_and_set_exn but for trees.
val test_set_and_get :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:(unit -> info) ->
t ->
path ->
test:contents option ->
set:contents option ->
(commit option, write_error) result Lwt.ttest_set_and_get is like test_and_set except it also returns the commit associated with updating the store with the new value if the test_and_set is successful. No commit is returned if there was no update to the store.
val test_set_and_get_exn :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:(unit -> info) ->
t ->
path ->
test:contents option ->
set:contents option ->
commit option Lwt.ttest_set_and_get_exn is like test_set_and_get but raises Failure _ instead.
val test_set_and_get_tree :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:(unit -> info) ->
t ->
path ->
test:tree option ->
set:tree option ->
(commit option, write_error) result Lwt.ttest_set_and_get_tree is like test_set_and_get but for a tree
val test_set_and_get_tree_exn :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:(unit -> info) ->
t ->
path ->
test:tree option ->
set:tree option ->
commit option Lwt.ttest_set_and_get_tree_exn is like test_set_and_get_tree but raises Failure _ instead.
val merge :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
old:contents option ->
t ->
path ->
contents option ->
(unit, write_error) result Lwt.tmerge ~old is like set but merge the current tree and the new tree using old as ancestor in case of conflicts.
This function always uses Metadata.default as metadata. Use merge_tree with `Contents (c, m) for different ones.
The result is Error (`Conflict c) if the merge failed with the conflict c.
The result is Error `Too_many_retries if the concurrent operations do not allow the operation to commit to the underlying storage layer (livelock).
val merge_exn :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
old:contents option ->
t ->
path ->
contents option ->
unit Lwt.tmerge_exn is like merge but raise Failure _ instead of using a result type.
val merge_tree :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
old:tree option ->
t ->
path ->
tree option ->
(unit, write_error) result Lwt.tmerge_tree is like merge_tree but for trees.
val merge_tree_exn :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
info:Info.f ->
old:tree option ->
t ->
path ->
tree option ->
unit Lwt.tmerge_tree is like merge_tree but for trees.
val with_tree :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
?strategy:[ `Set | `Test_and_set | `Merge ] ->
info:Info.f ->
t ->
path ->
(tree option -> tree option Lwt.t) ->
(unit, write_error) result Lwt.twith_tree t k ~info f replaces atomically the subtree v under k in the store t by the contents of the tree f v, using the commit info info ().
If v = f v and allow_empty is unset (default) then, the operation is a no-op.
If v != f v and no other changes happen concurrently, f v becomes the new subtree under k. If other changes happen concurrently to that operations, the semantics depend on the value of strategy:
- if
strategy = `Set, usesetand discard any concurrent updates tok. - if
strategy = `Test_and_set(default), usetest_and_setand ensure that no concurrent operations are updatingk. - if
strategy = `Merge, usemergeand ensure that concurrent updates and merged with the values present at the beginning of the transaction.
Note: Irmin transactions provides snapshot isolation guarantees: reads and writes are isolated in every transaction, but only write conflicts are visible on commit.
val with_tree_exn :
?clear:bool ->
?retries:int ->
?allow_empty:bool ->
?parents:commit list ->
?strategy:[ `Set | `Test_and_set | `Merge ] ->
info:Info.f ->
t ->
path ->
(tree option -> tree option Lwt.t) ->
unit Lwt.twith_tree_exn is like with_tree but raise Failure _ instead of using a return type.
Clones
clone ~src ~dst makes dst points to Head.get src. dst is created if needed. Remove the current contents en dst if src is empty.
Watches
The type for store watches.
watch t f calls f every time the contents of t's head is updated.
Note: even if f might skip some head updates, it will never be called concurrently: all consecutive calls to f are done in sequence, so we ensure that the previous one ended before calling the next one.
val watch_key :
t ->
path ->
?init:commit ->
((commit * tree) Diff.t -> unit Lwt.t) ->
watch Lwt.twatch_key t key f calls f every time the key's value is added, removed or updated. If the current branch is deleted, no signal is sent to the watcher.
Merges and Common Ancestors
type 'a merge =
info:Info.f ->
?max_depth:int ->
?n:int ->
'a ->
(unit, Merge.conflict) result Lwt.tThe type for merge functions.
merge_into ~into:x ~info:i t merges t's current branch into x's current branch using the info i. After that operation, the two stores are still independent. Similar to git merge <branch>.
lca ?max_depth ?n msg t1 t2 returns the collection of least common ancestors between the heads of t1 and t2 branches.
max_depthis the maximum depth of the exploration (default ismax_int). ReturnError `Max_depth_reachedif this depth is exceeded.nis the maximum expected number of lcas. Stop the exploration as soon asnlcas are found. ReturnError `Too_many_lcasif morelcasare found.
val lcas_with_branch :
t ->
?max_depth:int ->
?n:int ->
branch ->
(commit list, lca_error) result Lwt.tSame as lcas but takes a branch ID as argument.
val lcas_with_commit :
t ->
?max_depth:int ->
?n:int ->
commit ->
(commit list, lca_error) result Lwt.tSame as lcas but takes a commmit as argument.
History
An history is a DAG of heads.
history ?depth ?min ?max t is a view of the history of the store t, of depth at most depth, starting from the t's head (or from max if the head is not set) and stopping at min if specified.
last_modified ?number c k is the list of the last number commits that modified path, in ascending order of date. depth is the maximum depth to be explored in the commit graph, if any. Default value for number is 1.
Path provides base functions for the stores's paths.
Metadata provides base functions for node metadata.
module Backend :
Backend.S
with module Schema = Schema
with type Slice.t = slice
and type Repo.t = repo
and module Hash = Hash
and module Node.Path = Path
and type Contents.key = contents_key
and type Node.key = node_key
and type Commit.key = commit_keyBackend functions, which might be used by the backends.
type Irmin__.Remote.t += | E of Backend.Remote.endpoint(*Extend the
*)remotetype withendpoint.
Converters to backend types
to_backend_commit c is the backend commit object associated with the commit c.
of_backend_commit r k c is the commit associated with the backend commit object c that hash key k in r.
Save a content into the database
val save_tree :
?clear:bool ->
repo ->
[> Perms.write ] Backend.Contents.t ->
[> Perms.read_write ] Backend.Node.t ->
tree ->
kinded_key Lwt.tSave a tree into the database. Does not do any reads.
When clear is set (the default), the tree cache is emptied upon the function's completion, mirroring the effect of invoking Tree.clear.