Rust crate for managing the building of artifacts by builders which are connected in a directed acyclic graph (DAG) like manner.
This crate provides essentially a cache which keeps artifacts of builders in order to prevent the same builder to produce multiple equal artifacts. This could be useful if the builders use consumable resources to create their artifacts, the building is a heavyweight procedure, or a given DAG dependency structure among the builders shall be properly preserved among their artifacts.
The basic principal on which this crate is build, suggests two levels of
abstraction, the builder level and the artifact level. Each builder type has
one specific artifact type. The builders are represented by any struct,
which implements the Builder trait, which in turn has an associate type
that specifies the artifact type.
Builders are supposed to be wrapped in ArtifactPromises, which prevents
to call its Builder::build() method directly. In other respects, the
ArtifactPromise acts a lot like an Rc and thus allows to share one
instance among several dependants.
This Rc-like structure creates naturally a DAG.
For building a Builders artifact, its Builder::build() method is
provided with a ArtifactResolver that allows to resolve depending
ArtifactPromises into their respective artifacts, which is,
in order to form a DAG, wrapped behind a Rc.
As entry point serves the ArtifactCache, which allows outside of a
Builder to resolve any ArtifactPromise to its artifact. The
ArtifactCache is essentially a cache for artifacts. It can be used to
translate any number of ArtifactPromises to their respective artifact,
while sharing their common dependencies.
Consequently, resolving the same ArtifactPromise using the same
ArtifactCache results in the same Rced artifact.
However, using different ArtifactCaches results in different artifacts.
The ArtifactCache has a clear() method to reset the cache.
This could be useful to free the resources kept by all artifacts and
builders, which are cached in it, or when artifacts shall be explicitly
recreated, e.g. to form a second independent artifact DAG.
Additionally, ArtifactCache has an invalidate() method to remove a single
builder and artifact including its dependants (i.e. those artifacts which had
used the invalidated one).
Minimal Rust version: 1.40
```rust use std::rc::Rc; use daab::*;
// Simple artifact
struct Leaf { //... }
// Simple builder
struct BuilderLeaf { // ... } impl BuilderLeaf { pub fn new() -> Self { Self { // ... } } } impl Builder for BuilderLeaf { type Artifact = Leaf;
fn build(&self, _cache: &mut ArtifactResolver) -> Self::Artifact {
Leaf{
// ...
}
}
}
// Composed artifact, linking to a Leaf
struct Node {
leaf: Rc
// Composed builder, depending on BuilderLeaf
struct BuilderNode {
builderleaf: ArtifactPromise
fn build(&self, cache: &mut ArtifactResolver) -> Self::Artifact {
// Resolve ArtifactPromise to its artifact
let leaf = cache.resolve(&self.builder_leaf);
Node {
leaf,
// ...
}
}
}
// The cache to storing already created artifacts let mut cache = ArtifactCache::new();
// Constructing builders let leaf_builder = ArtifactPromise::new(BuilderLeaf::new());
let nodebuilder1 = ArtifactPromise::new(BuilderNode::new(leafbuilder.clone())); let nodebuilder2: ArtifactPromise<_> = BuilderNode::new(leafbuilder.clone()).into();
// Using the cache to access the artifacts from the builders
// The same builder results in same artifact assert!(Rc::ptreq(&cache.get(&nodebuilder1), &cache.get(&nodebuilder_1)));
// Different builders result in different artifacts assert!( ! Rc::ptreq(&cache.get(&nodebuilder1), &cache.get(&nodebuilder_2)));
// Different artifacts may link the same dependent artifact assert!(Rc::ptreq(&cache.get(&nodebuilder1).leaf, &cache.get(&nodebuilder_2).leaf)); ```
daab comes with extensive debugging gear. However, in order to
keep the production impact as low as possible, the debugging facilities
are capsuled behind the diagnostics feature.
Of course, the debugging feature is for the user of this crate to
debug their graphs. Therefore, it is rather modelled as a
diagnostics feature (hence the name). The diagnosis
is carried out by a Doctor, which is a trait receiving various
internal events in order to record them, print them, or otherwise help
treating the bug.
Care has been taken to keep the diagnostics feature broadly applicable
as well as keeping the non-diagnostics API compatible with the
diagnostics-API, meaning that a project not using the
diagnostics feature can be easily converted to using
diagnostics, usually by just replacing ArtifactCache::new()
with ArtifactCache::new_with_doctor().
In order to store the Doctor the ArtifactCache is generic to a doctor,
which is important on its creation and for storing it by value.
The rest of the time the ArtifactCache uses dyn Doctor as its default
generic argument.
To ease conversion between them, all creatable ArtifactCaches
(i.e. not ArtifactCache<dyn Doctor>) implement DerefMut to
&mut ArtifactCache<dyn Doctor> which has all the important methods
implemented.
This crate offers the following features:
diagnostics enables elaborate graph and cache interaction debugging.
It adds the new_with_doctor() function to the ArtifactCache and adds
the diagnostics module with the Doctor trait definition and some
default Doctors.
tynm enable the optional dependency on the [tynm] crate which adds
functionality to abbreviate type names, which are used by some default
Doctors, hence it is only useful in connection with the diagnostics
feature.
Licensed under Apache License, Version 2.0 (LICENSE or https://www.apache.org/licenses/LICENSE-2.0).
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Apache-2.0 license, shall be licensed as above, without any additional terms or conditions.