1f1a42b4da
To make use of the filtering feature, we need to revert the internal walker to a real DFS.
We will therefore just invert the whole tree by storing all of its
contents in a level-keyed vector.
This is horribly expensive in memory, this is a compromise between CPU
and memory, here is the fundamental reason for why:
When you encounter a directory, it's either a leaf or not, i.e. it
contains subdirectories or not.
To know this fact, you can:
- wait until you notice subdirectories under it, i.e. you need to store
any intermediate nodes you see in the meantime -> memory penalty.
- getdents or readdir on it to determine *NOW* its subdirectories -> CPU
penalty and I/O penalty.
This is an implementation of the first proposal, we pay memory.
In practice, we are paying O(#nb of nodes) in memory.
There's a smarter albeit much more complicated algorithm that pays only
O(\sum_i #siblings(p_i)) nodes where (p_1, ..., p_n) is the path to a leaf.
which means for:
A
/ \
B C
/ / \
D E F
We would never store D, E, F but only E, F at a given time.
But we would still store B, C no matter what.
Change-Id: I456ed1c3f0db493e018ba1182665d84bebe29c11
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10567
Tested-by: BuildkiteCI
Autosubmit: raitobezarius <tvl@lahfa.xyz>
Reviewed-by: flokli <flokli@flokli.de>
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|---|---|---|
| .. | ||
| .vscode | ||
| boot | ||
| build | ||
| build-go | ||
| castore | ||
| castore-go | ||
| cli | ||
| docs | ||
| eval | ||
| glue | ||
| nar-bridge | ||
| nix-compat | ||
| scripts | ||
| serde | ||
| store | ||
| store-go | ||
| tools | ||
| verify-lang-tests | ||
| website | ||
| .gitignore | ||
| buildkite.yml | ||
| Cargo.lock | ||
| Cargo.nix | ||
| Cargo.toml | ||
| clippy.toml | ||
| crate-hashes.json | ||
| default.nix | ||
| LICENSE | ||
| logo.webp | ||
| OWNERS | ||
| README.md | ||
| shell.nix | ||
Tvix is a new implementation of the Nix language and package manager. See the announcement post for information about the background of this project.
Tvix is developed by TVL in our monorepo, the depot, at
//tvix. Code reviews take place on Gerrit, bugs are
filed in our issue tracker.
For more information about Tvix, feel free to reach out. We are interested in people who would like to help us review designs, brainstorm and describe requirements that we may not yet have considered.
Most of the discussion around development happens on our IRC channel, which you can join in several ways documented on tvl.fyi, or on our mailing list.
Contributions to Tvix follow the TVL review flow and contribution guidelines.
WARNING: Tvix is not ready for use in production. None of our current APIs should be considered stable in any way.
WARNING: Any other instances of this project or repository are
josh-mirrors. We do not accept code contributions or issues outside of
the tooling and communication methods outlined above.
Components
This folder contains the following components:
//tvix/castore- subtree storage/transfer in a content-addressed fashion//tvix/cli- preliminary REPL & CLI implementation for Tvix//tvix/eval- an implementation of the Nix programming language//tvix/nar-bridgenar-bridge-http: A HTTP webserver providing a Nix HTTP Binary Cache interface in front of a tvix-store
//tvix/nix-compat- a Rust library for compatibility with C++ Nix, features like encodings and hashing schemes and formats//tvix/serde- a Rust library for using the Nix language for app configuration//tvix/store- a "filesystem" linking Nix store paths and metadata with the content-addressed layer
Some additional folders with auxiliary things exist and can be explored at your leisure.
Building the CLI
The CLI can also be built with standard Rust tooling (i.e. cargo build),
as long as you are in a shell with the right dependencies.
- If you cloned the full monorepo, it can be provided by
mg shell //tvix:shell. - If you cloned the
tvixworkspace only (git clone https://code.tvl.fyi/depot.git:workspace=views/tvix.git),nix-shellprovides it.
If you're in the TVL monorepo, you can also run mg build //tvix/cli
(or mg build from inside that folder) for a more incremental build.
Please follow the depot-wide instructions on how to get mg and use the depot
tooling.
Compatibility
Important note: We only use and test Nix builds of our software against Nix 2.3. There are a variety of bugs and subtle problems in newer Nix versions which we do not have the bandwidth to address, builds in newer Nix versions may or may not work.
Rust projects, crate2nix
Some parts of Tvix are written in Rust. To simplify the dependency
management on the Nix side of these builds, we use crate2nix in a
single Rust workspace in //tvix to maintain the Nix build
configuration.
When making changes to Cargo dependency configuration in any of the
Rust projects under //tvix, be sure to run
mg run //tools:crate2nix-generate in //tvix itself and commit the changes
to the generated Cargo.nix file. This only applies to the full TVL checkout.
License structure
All code implemented for Tvix is licensed under the GPL-3.0, with the exception of the protocol buffer definitions used for communication between services which are available under a more permissive license (MIT).
The idea behind this structure is that any direct usage of our code (e.g. linking to it, embedding the evaluator, etc.) will fall under the terms of the GPL3, but users are free to implement their own components speaking these protocols under the terms of the MIT license.