diff options
Diffstat (limited to 'src/libstore/derivations.hh')
| -rw-r--r-- | src/libstore/derivations.hh | 111 |
1 files changed, 104 insertions, 7 deletions
diff --git a/src/libstore/derivations.hh b/src/libstore/derivations.hh index 112b2a8ca..38c4b75c0 100644 --- a/src/libstore/derivations.hh +++ b/src/libstore/derivations.hh @@ -6,6 +6,7 @@ #include "content-address.hh" #include <map> +#include <variant> namespace nix { @@ -13,30 +14,87 @@ namespace nix { /* Abstract syntax of derivations. */ +/* The traditional non-fixed-output derivation type. */ struct DerivationOutputInputAddressed { + /* Will need to become `std::optional<StorePath>` once input-addressed + derivations are allowed to depend on cont-addressed derivations */ StorePath path; }; -struct DerivationOutputFixed +/* Fixed-output derivations, whose output paths are content addressed + according to that fixed output. */ +struct DerivationOutputCAFixed { FixedOutputHash hash; /* hash used for expected hash computation */ }; +/* Floating-output derivations, whose output paths are content addressed, but + not fixed, and so are dynamically calculated from whatever the output ends + up being. */ +struct DerivationOutputCAFloating +{ + /* information used for expected hash computation */ + FileIngestionMethod method; + HashType hashType; +}; + struct DerivationOutput { - std::variant<DerivationOutputInputAddressed, DerivationOutputFixed> output; - StorePath path(const Store & store, std::string_view drvName) const; + std::variant< + DerivationOutputInputAddressed, + DerivationOutputCAFixed, + DerivationOutputCAFloating + > output; + std::optional<HashType> hashAlgoOpt(const Store & store) const; + /* Note, when you use this function you should make sure that you're passing + the right derivation name. When in doubt, you should use the safer + interface provided by BasicDerivation::outputsAndPaths */ + std::optional<StorePath> pathOpt(const Store & store, std::string_view drvName) const; + /* DEPRECATED: Remove after CA drvs are fully implemented */ + StorePath path(const Store & store, std::string_view drvName) const { + auto p = pathOpt(store, drvName); + if (!p) throw UnimplementedError("floating content-addressed derivations are not yet implemented"); + return *p; + } }; typedef std::map<string, DerivationOutput> DerivationOutputs; +/* These are analogues to the previous DerivationOutputs data type, but they + also contains, for each output, the (optional) store path in which it would + be written. To calculate values of these types, see the corresponding + functions in BasicDerivation */ +typedef std::map<string, std::pair<DerivationOutput, StorePath>> + DerivationOutputsAndPaths; +typedef std::map<string, std::pair<DerivationOutput, std::optional<StorePath>>> + DerivationOutputsAndOptPaths; + /* For inputs that are sub-derivations, we specify exactly which output IDs we are interested in. */ typedef std::map<StorePath, StringSet> DerivationInputs; typedef std::map<string, string> StringPairs; +enum struct DerivationType : uint8_t { + InputAddressed, + CAFixed, + CAFloating, +}; + +/* Do the outputs of the derivation have paths calculated from their content, + or from the derivation itself? */ +bool derivationIsCA(DerivationType); + +/* Is the content of the outputs fixed a-priori via a hash? Never true for + non-CA derivations. */ +bool derivationIsFixed(DerivationType); + +/* Is the derivation impure and needs to access non-deterministic resources, or + pure and can be sandboxed? Note that whether or not we actually sandbox the + derivation is controlled separately. Never true for non-CA derivations. */ +bool derivationIsImpure(DerivationType); + struct BasicDerivation { DerivationOutputs outputs; /* keyed on symbolic IDs */ @@ -53,7 +111,7 @@ struct BasicDerivation bool isBuiltin() const; /* Return true iff this is a fixed-output derivation. */ - bool isFixedOutput() const; + DerivationType type() const; /* Return the output paths of a derivation. */ StorePathSet outputPaths(const Store & store) const; @@ -61,6 +119,13 @@ struct BasicDerivation /* Return the output names of a derivation. */ StringSet outputNames() const; + /* Calculates the maps that contains all the DerivationOutputs, but + augmented with knowledge of the Store paths they would be written into. + The first one of these functions will be removed when the CA work is + completed */ + DerivationOutputsAndPaths outputsAndPaths(const Store & store) const; + DerivationOutputsAndOptPaths outputsAndOptPaths(const Store & store) const; + static std::string_view nameFromPath(const StorePath & storePath); }; @@ -82,7 +147,7 @@ enum RepairFlag : bool { NoRepair = false, Repair = true }; /* Write a derivation to the Nix store, and return its path. */ StorePath writeDerivation(ref<Store> store, - const Derivation & drv, std::string_view name, RepairFlag repair = NoRepair); + const Derivation & drv, RepairFlag repair = NoRepair); /* Read a derivation from a file. */ Derivation parseDerivation(const Store & store, std::string && s, std::string_view name); @@ -90,10 +155,42 @@ Derivation parseDerivation(const Store & store, std::string && s, std::string_vi // FIXME: remove bool isDerivation(const string & fileName); -Hash hashDerivationModulo(Store & store, const Derivation & drv, bool maskOutputs); +// known CA drv's output hashes, current just for fixed-output derivations +// whose output hashes are always known since they are fixed up-front. +typedef std::map<std::string, Hash> CaOutputHashes; + +typedef std::variant< + Hash, // regular DRV normalized hash + CaOutputHashes +> DrvHashModulo; + +/* Returns hashes with the details of fixed-output subderivations + expunged. + + A fixed-output derivation is a derivation whose outputs have a + specified content hash and hash algorithm. (Currently they must have + exactly one output (`out'), which is specified using the `outputHash' + and `outputHashAlgo' attributes, but the algorithm doesn't assume + this.) We don't want changes to such derivations to propagate upwards + through the dependency graph, changing output paths everywhere. + + For instance, if we change the url in a call to the `fetchurl' + function, we do not want to rebuild everything depending on it---after + all, (the hash of) the file being downloaded is unchanged. So the + *output paths* should not change. On the other hand, the *derivation + paths* should change to reflect the new dependency graph. + + For fixed-output derivations, this returns a map from the name of + each output to its hash, unique up to the output's contents. + + For regular derivations, it returns a single hash of the derivation + ATerm, after subderivations have been likewise expunged from that + derivation. + */ +DrvHashModulo hashDerivationModulo(Store & store, const Derivation & drv, bool maskOutputs); /* Memoisation of hashDerivationModulo(). */ -typedef std::map<StorePath, Hash> DrvHashes; +typedef std::map<StorePath, DrvHashModulo> DrvHashes; extern DrvHashes drvHashes; // FIXME: global, not thread-safe |