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201551c937
Part of RFC 133 Extracted from our old IPFS branches. Co-Authored-By: Matthew Bauer <mjbauer95@gmail.com> Co-Authored-By: Carlo Nucera <carlo.nucera@protonmail.com> Co-authored-by: Robert Hensing <roberth@users.noreply.github.com> Co-authored-by: Florian Klink <flokli@flokli.de>
145 lines
3.7 KiB
C++
145 lines
3.7 KiB
C++
#pragma once
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///@file
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#include "source-accessor.hh"
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#include "fs-sink.hh"
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#include "util.hh"
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namespace nix {
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/**
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* An enumeration of the ways we can serialize file system
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* objects.
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*/
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enum struct FileSerialisationMethod : uint8_t {
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/**
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* Flat-file. The contents of a single file exactly.
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*/
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Flat,
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/**
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* Nix Archive. Serializes the file-system object in
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* Nix Archive format.
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*/
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Recursive,
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};
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/**
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* Parse a `FileSerialisationMethod` by name. Choice of:
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*
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* - `flat`: `FileSerialisationMethod::Flat`
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* - `nar`: `FileSerialisationMethod::Recursive`
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*
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* Opposite of `renderFileSerialisationMethod`.
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*/
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FileSerialisationMethod parseFileSerialisationMethod(std::string_view input);
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/**
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* Render a `FileSerialisationMethod` by name.
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*
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* Opposite of `parseFileSerialisationMethod`.
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*/
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std::string_view renderFileSerialisationMethod(FileSerialisationMethod method);
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/**
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* Dump a serialization of the given file system object.
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*/
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void dumpPath(
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SourceAccessor & accessor, const CanonPath & path,
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Sink & sink,
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FileSerialisationMethod method,
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PathFilter & filter = defaultPathFilter);
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/**
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* Restore a serialisation of the given file system object.
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*
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* @TODO use an arbitrary `FileSystemObjectSink`.
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*/
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void restorePath(
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const Path & path,
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Source & source,
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FileSerialisationMethod method);
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/**
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* Compute the hash of the given file system object according to the
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* given method.
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*
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* the hash is defined as (in pseudocode):
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*
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* ```
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* hashString(ha, dumpPath(...))
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* ```
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*/
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HashResult hashPath(
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SourceAccessor & accessor, const CanonPath & path,
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FileSerialisationMethod method, HashAlgorithm ha,
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PathFilter & filter = defaultPathFilter);
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/**
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* An enumeration of the ways we can ingest file system
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* objects, producing a hash or digest.
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*/
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enum struct FileIngestionMethod : uint8_t {
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/**
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* Hash `FileSerialisationMethod::Flat` serialisation.
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*/
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Flat,
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/**
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* Hash `FileSerialisationMethod::Git` serialisation.
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*/
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Recursive,
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/**
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* Git hashing. In particular files are hashed as git "blobs", and
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* directories are hashed as git "trees".
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*
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* Unlike `Flat` and `Recursive`, this is not a hash of a single
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* serialisation but a [Merkle
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* DAG](https://en.wikipedia.org/wiki/Merkle_tree) of multiple
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* rounds of serialisation and hashing.
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*
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* @note Git's data model is slightly different, in that a plain
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* file doesn't have an executable bit, directory entries do
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* instead. We decide treat a bare file as non-executable by fiat,
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* as we do with `FileIngestionMethod::Flat` which also lacks this
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* information. Thus, Git can encode some but all of Nix's "File
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* System Objects", and this sort of hashing is likewise partial.
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*/
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Git,
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};
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/**
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* Parse a `FileIngestionMethod` by name. Choice of:
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*
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* - `flat`: `FileIngestionMethod::Flat`
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* - `nar`: `FileIngestionMethod::Recursive`
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* - `git`: `FileIngestionMethod::Git`
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*
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* Opposite of `renderFileIngestionMethod`.
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*/
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FileIngestionMethod parseFileIngestionMethod(std::string_view input);
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/**
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* Render a `FileIngestionMethod` by name.
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*
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* Opposite of `parseFileIngestionMethod`.
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*/
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std::string_view renderFileIngestionMethod(FileIngestionMethod method);
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/**
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* Compute the hash of the given file system object according to the
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* given method.
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*
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* Unlike the other `hashPath`, this works on an arbitrary
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* `FileIngestionMethod` instead of `FileSerialisationMethod`, but
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* doesn't return the size as this is this is not a both simple and
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* useful defined for a merkle format.
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*/
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Hash hashPath(
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SourceAccessor & accessor, const CanonPath & path,
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FileIngestionMethod method, HashAlgorithm ha,
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PathFilter & filter = defaultPathFilter);
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}
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