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Simplify ContentAddress

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Whereas `ContentAddressWithReferences` is a sum type complex because different
varieties support different notions of reference, and
`ContentAddressMethod` is a nested enum to support that,
`ContentAddress` can be a simple pair of a method and hash.

`ContentAddress` does not need to be a sum type on the outside because
the choice of method doesn't effect what type of hashes we can use.

Co-Authored-By: Cale Gibbard <cgibbard@gmail.com>
This commit is contained in:
John Ericson 2023-07-05 18:53:44 -04:00
parent 6db66ebfc5
commit 903700c5e1
20 changed files with 182 additions and 293 deletions
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91
src/libstore/content-address.hh
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@ -113,37 +113,6 @@ struct ContentAddressMethod
* Mini content address
*/
/**
* 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);
};
/**
* Used by most store objects that are content-addressed.
*/
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
@ -158,19 +127,17 @@ struct FixedOutputHash {
*/
struct ContentAddress
{
typedef std::variant<
TextHash,
FixedOutputHash
> Raw;
/**
* How the file system objects are serialized
*/
ContentAddressMethod method;
Raw raw;
/**
* Hash of that serialization
*/
Hash hash;
GENERATE_CMP(ContentAddress, me->raw);
/* The moral equivalent of `using Raw::Raw;` */
ContentAddress(auto &&... arg)
: raw(std::forward<decltype(arg)>(arg)...)
{ }
GENERATE_CMP(ContentAddress, me->method, me->hash);
/**
* Compute the content-addressability assertion
@ -183,20 +150,6 @@ struct ContentAddress
static std::optional<ContentAddress> parseOpt(std::string_view rawCaOpt);
/**
* Create a `ContentAddress` from 2 parts:
*
* @param method Way ingesting the file system data.
*
* @param hash Hash of ingested file system data.
*/
static ContentAddress fromParts(
ContentAddressMethod method, Hash hash) noexcept;
ContentAddressMethod getMethod() const;
const Hash & getHash() const;
std::string printMethodAlgo() const;
};
@ -219,7 +172,8 @@ std::string renderContentAddress(std::optional<ContentAddress> ca);
* References to other store objects are tracked with store paths, self
* references however are tracked with a boolean.
*/
struct StoreReferences {
struct StoreReferences
{
/**
* References to other store objects
*/
@ -246,8 +200,13 @@ struct StoreReferences {
};
// This matches the additional info that we need for makeTextPath
struct TextInfo {
TextHash hash;
struct TextInfo
{
/**
* Hash of the contents of the text/file.
*/
Hash hash;
/**
* References to other store objects only; self references
* disallowed
@ -257,8 +216,18 @@ struct TextInfo {
GENERATE_CMP(TextInfo, me->hash, me->references);
};
struct FixedOutputInfo {
FixedOutputHash hash;
struct FixedOutputInfo
{
/**
* How the file system objects are serialized
*/
FileIngestionMethod method;
/**
* Hash of that serialization
*/
Hash hash;
/**
* References to other store objects or this one.
*/