forked from lix-project/lix
120 lines
2.9 KiB
C++
120 lines
2.9 KiB
C++
#pragma once
|
||
///@file
|
||
|
||
#include <variant>
|
||
#include "hash.hh"
|
||
#include "comparator.hh"
|
||
|
||
namespace nix {
|
||
|
||
/**
|
||
* An enumeration of the ways we can serialize file system objects.
|
||
*/
|
||
enum struct FileIngestionMethod : uint8_t {
|
||
/**
|
||
* Flat-file hashing. Directly ingest the contents of a single file
|
||
*/
|
||
Flat = false,
|
||
/**
|
||
* Recursive (or NAR) hashing. Serializes the file-system object in Nix
|
||
* Archive format and ingest that
|
||
*/
|
||
Recursive = true
|
||
};
|
||
|
||
/**
|
||
* Somewhat obscure, used by \ref Derivation derivations and
|
||
* `builtins.toFile` currently.
|
||
*/
|
||
struct TextHash {
|
||
/**
|
||
* Hash of the contents of the text/file.
|
||
*/
|
||
Hash hash;
|
||
|
||
GENERATE_CMP(TextHash, me->hash);
|
||
};
|
||
|
||
/**
|
||
* For path computed by makeFixedOutputPath.
|
||
*/
|
||
struct FixedOutputHash {
|
||
/**
|
||
* How the file system objects are serialized
|
||
*/
|
||
FileIngestionMethod method;
|
||
/**
|
||
* Hash of that serialization
|
||
*/
|
||
Hash hash;
|
||
|
||
std::string printMethodAlgo() const;
|
||
|
||
GENERATE_CMP(FixedOutputHash, me->method, me->hash);
|
||
};
|
||
|
||
/**
|
||
* We've accumulated several types of content-addressed paths over the
|
||
* years; fixed-output derivations support multiple hash algorithms and
|
||
* serialisation methods (flat file vs NAR). Thus, ‘ca’ has one of the
|
||
* following forms:
|
||
*
|
||
* - ‘text:sha256:<sha256 hash of file contents>’: For paths
|
||
* computed by Store::makeTextPath() / Store::addTextToStore().
|
||
*
|
||
* - ‘fixed:<r?>:<ht>:<h>’: For paths computed by
|
||
* Store::makeFixedOutputPath() / Store::addToStore().
|
||
*/
|
||
typedef std::variant<
|
||
TextHash,
|
||
FixedOutputHash
|
||
> ContentAddress;
|
||
|
||
/**
|
||
* Compute the prefix to the hash algorithm which indicates how the
|
||
* files were ingested.
|
||
*/
|
||
std::string makeFileIngestionPrefix(const FileIngestionMethod m);
|
||
|
||
/**
|
||
* Compute the content-addressability assertion (ValidPathInfo::ca) for
|
||
* paths created by Store::makeFixedOutputPath() / Store::addToStore().
|
||
*/
|
||
std::string makeFixedOutputCA(FileIngestionMethod method, const Hash & hash);
|
||
|
||
std::string renderContentAddress(ContentAddress ca);
|
||
|
||
std::string renderContentAddress(std::optional<ContentAddress> ca);
|
||
|
||
ContentAddress parseContentAddress(std::string_view rawCa);
|
||
|
||
std::optional<ContentAddress> parseContentAddressOpt(std::string_view rawCaOpt);
|
||
|
||
Hash getContentAddressHash(const ContentAddress & ca);
|
||
|
||
/*
|
||
We only have one way to hash text with references, so this is single-value
|
||
type is only useful in std::variant.
|
||
*/
|
||
struct TextHashMethod { };
|
||
struct FixedOutputHashMethod {
|
||
FileIngestionMethod fileIngestionMethod;
|
||
HashType hashType;
|
||
};
|
||
|
||
/**
|
||
* Ways of content addressing but not a complete ContentAddress.
|
||
*
|
||
* A ContentAddress without a Hash.
|
||
*/
|
||
typedef std::variant<
|
||
TextHashMethod,
|
||
FixedOutputHashMethod
|
||
> ContentAddressMethod;
|
||
|
||
ContentAddressMethod parseContentAddressMethod(std::string_view rawCaMethod);
|
||
|
||
std::string renderContentAddressMethod(ContentAddressMethod caMethod);
|
||
|
||
}
|