lix/src/libstore/derivations.hh

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#pragma once
#include "path.hh"
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#include "types.hh"
#include "hash.hh"
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#include "file-hash.hh"
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#include <map>
namespace nix {
/* Abstract syntax of derivations. */
* Removed the `id' attribute hack. * Formalise the notion of fixed-output derivations, i.e., derivations for which a cryptographic hash of the output is known in advance. Changes to such derivations should not propagate upwards through the dependency graph. Previously this was done by specifying the hash component of the output path through the `id' attribute, but this is insecure since you can lie about it (i.e., you can specify any hash and then produce a completely different output). Now the responsibility for checking the output is moved from the builder to Nix itself. A fixed-output derivation can be created by specifying the `outputHash' and `outputHashAlgo' attributes, the latter taking values `md5', `sha1', and `sha256', and the former specifying the actual hash in hexadecimal or in base-32 (auto-detected by looking at the length of the attribute value). MD5 is included for compatibility but should be considered deprecated. * Removed the `drvPath' pseudo-attribute in derivation results. It's no longer necessary. * Cleaned up the support for multiple output paths in derivation store expressions. Each output now has a unique identifier (e.g., `out', `devel', `docs'). Previously there was no way to tell output paths apart at the store expression level. * `nix-hash' now has a flag `--base32' to specify that the hash should be printed in base-32 notation. * `fetchurl' accepts parameters `sha256' and `sha1' in addition to `md5'. * `nix-prefetch-url' now prints out a SHA-1 hash in base-32. (TODO: a flag to specify the hash.)
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struct DerivationOutput
{
StorePath path;
std::optional<FileSystemHash> hash; /* hash used for expected hash computation */
DerivationOutput(StorePath && path, std::optional<FileSystemHash> && hash)
: path(std::move(path))
, hash(std::move(hash))
{ }
DerivationOutput(const DerivationOutput &) = default;
DerivationOutput(DerivationOutput &&) = default;
DerivationOutput & operator = (const DerivationOutput &) = default;
* Removed the `id' attribute hack. * Formalise the notion of fixed-output derivations, i.e., derivations for which a cryptographic hash of the output is known in advance. Changes to such derivations should not propagate upwards through the dependency graph. Previously this was done by specifying the hash component of the output path through the `id' attribute, but this is insecure since you can lie about it (i.e., you can specify any hash and then produce a completely different output). Now the responsibility for checking the output is moved from the builder to Nix itself. A fixed-output derivation can be created by specifying the `outputHash' and `outputHashAlgo' attributes, the latter taking values `md5', `sha1', and `sha256', and the former specifying the actual hash in hexadecimal or in base-32 (auto-detected by looking at the length of the attribute value). MD5 is included for compatibility but should be considered deprecated. * Removed the `drvPath' pseudo-attribute in derivation results. It's no longer necessary. * Cleaned up the support for multiple output paths in derivation store expressions. Each output now has a unique identifier (e.g., `out', `devel', `docs'). Previously there was no way to tell output paths apart at the store expression level. * `nix-hash' now has a flag `--base32' to specify that the hash should be printed in base-32 notation. * `fetchurl' accepts parameters `sha256' and `sha1' in addition to `md5'. * `nix-prefetch-url' now prints out a SHA-1 hash in base-32. (TODO: a flag to specify the hash.)
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};
typedef std::map<string, DerivationOutput> DerivationOutputs;
/* 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;
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struct BasicDerivation
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{
* Removed the `id' attribute hack. * Formalise the notion of fixed-output derivations, i.e., derivations for which a cryptographic hash of the output is known in advance. Changes to such derivations should not propagate upwards through the dependency graph. Previously this was done by specifying the hash component of the output path through the `id' attribute, but this is insecure since you can lie about it (i.e., you can specify any hash and then produce a completely different output). Now the responsibility for checking the output is moved from the builder to Nix itself. A fixed-output derivation can be created by specifying the `outputHash' and `outputHashAlgo' attributes, the latter taking values `md5', `sha1', and `sha256', and the former specifying the actual hash in hexadecimal or in base-32 (auto-detected by looking at the length of the attribute value). MD5 is included for compatibility but should be considered deprecated. * Removed the `drvPath' pseudo-attribute in derivation results. It's no longer necessary. * Cleaned up the support for multiple output paths in derivation store expressions. Each output now has a unique identifier (e.g., `out', `devel', `docs'). Previously there was no way to tell output paths apart at the store expression level. * `nix-hash' now has a flag `--base32' to specify that the hash should be printed in base-32 notation. * `fetchurl' accepts parameters `sha256' and `sha1' in addition to `md5'. * `nix-prefetch-url' now prints out a SHA-1 hash in base-32. (TODO: a flag to specify the hash.)
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DerivationOutputs outputs; /* keyed on symbolic IDs */
StorePathSet inputSrcs; /* inputs that are sources */
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string platform;
Path builder;
Strings args;
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StringPairs env;
BasicDerivation() { }
explicit BasicDerivation(const BasicDerivation & other);
virtual ~BasicDerivation() { };
/* Return the path corresponding to the output identifier `id' in
the given derivation. */
const StorePath & findOutput(const std::string & id) const;
bool isBuiltin() const;
/* Return true iff this is a fixed-output derivation. */
bool isFixedOutput() const;
/* Return the output paths of a derivation. */
StorePathSet outputPaths() const;
};
struct Derivation : BasicDerivation
{
DerivationInputs inputDrvs; /* inputs that are sub-derivations */
/* Print a derivation. */
std::string unparse(const Store & store, bool maskOutputs,
std::map<std::string, StringSet> * actualInputs = nullptr) const;
Derivation() { }
Derivation(Derivation && other) = default;
explicit Derivation(const Derivation & other);
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};
class Store;
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);
/* Read a derivation from a file. */
Derivation readDerivation(const Store & store, const Path & drvPath);
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// FIXME: remove
bool isDerivation(const string & fileName);
Hash hashDerivationModulo(Store & store, const Derivation & drv, bool maskOutputs);
/* Memoisation of hashDerivationModulo(). */
typedef std::map<StorePath, Hash> DrvHashes;
extern DrvHashes drvHashes; // FIXME: global, not thread-safe
bool wantOutput(const string & output, const std::set<string> & wanted);
struct Source;
struct Sink;
Source & readDerivation(Source & in, const Store & store, BasicDerivation & drv);
void writeDerivation(Sink & out, const Store & store, const BasicDerivation & drv);
std::string hashPlaceholder(const std::string & outputName);
}