MST.Store behaviour (mst v0.1.0)

Behaviour for MST node block stores.

A store holds a mapping from DASL.CID to decoded MST.Node structs. All implementations must satisfy these callbacks. The store state is an opaque term managed by the implementation module.

The primary built-in implementation is MST.Store.Memory, a simple map-backed store suitable for in-memory use and tests.

Usage

An MST.Tree holds its store as a {module, state} pair. You interact with the store through the tree API; direct store access is only needed when building trees from external data (e.g., importing a CAR file).

store = MST.Store.Memory.new()
tree = MST.Tree.new(store)

Summary

Types

t()

Callbacks

cids(state)

Returns all CIDs present in the store.

get(state, t)

Retrieves a node by CID. Returns {:ok, node} or {:error, :not_found}.

has?(state, t)

Returns true if the store contains a node for the given CID.

put(state, t, t)

Stores a node under its CID. Returns updated state.

Functions

cids(arg)

Returns all CIDs present in the store.

get(arg, cid)

Retrieves a node from the store.

has?(arg, cid)

Returns true if the store contains a node for the given CID.

put(arg, cid, node)

Stores a node in the store, returning the updated {module, state} pair.

Types

t()

@type t() :: {module(), any()}

Callbacks

cids(state)

@callback cids(state :: any()) :: [DASL.CID.t()]

Returns all CIDs present in the store.

get(state, t)

@callback get(state :: any(), DASL.CID.t()) :: {:ok, MST.Node.t()} | {:error, :not_found}

Retrieves a node by CID. Returns {:ok, node} or {:error, :not_found}.

has?(state, t)

@callback has?(state :: any(), DASL.CID.t()) :: boolean()

Returns true if the store contains a node for the given CID.

put(state, t, t)

@callback put(state :: any(), DASL.CID.t(), MST.Node.t()) :: any()

Stores a node under its CID. Returns updated state.

Functions

cids(arg)

@spec cids(t()) :: [DASL.CID.t()]

Returns all CIDs present in the store.

get(arg, cid)

@spec get(t(), DASL.CID.t()) :: {:ok, MST.Node.t()} | {:error, :not_found}

Retrieves a node from the store.

Examples

iex> store = MST.Store.Memory.new()
iex> cid = DASL.CID.compute("test", :drisl)
iex> MST.Store.get(store, cid)
{:error, :not_found}

has?(arg, cid)

@spec has?(t(), DASL.CID.t()) :: boolean()

Returns true if the store contains a node for the given CID.

put(arg, cid, node)

@spec put(t(), DASL.CID.t(), MST.Node.t()) :: t()

Stores a node in the store, returning the updated {module, state} pair.

Examples

iex> store = MST.Store.Memory.new()
iex> node = MST.Node.empty()
iex> {:ok, cid} = MST.Node.cid(node)
iex> store2 = MST.Store.put(store, cid, node)
iex> {:ok, _} = MST.Store.get(store2, cid)
iex> :ok
:ok