Nix/src/libcmd/installable-value.hh
Robert Hensing 65255edc9b DerivationInfo -> PackageInfo
This does not yet resolve the coupling between packages and
derivations, but it makes the code more consistent with the
terminology, and it accentuates places where the coupling is
obvious, such as

         auto drvPath = packageInfo.queryDrvPath();
         if (!drvPath)
             throw Error("'%s' is not a derivation", what());

... which isn't wrong, and in my opinion, doesn't even look
wrong, because it just reflects the current logic.
However, I do like that we can now start to see in the code that
this coupling is perhaps a bit arbitrary.
After this rename, we can bring the DerivingPath concept into type
and start to lift this limitation.
2024-01-16 15:28:03 +01:00

122 lines
3.2 KiB
C++

#pragma once
///@file
#include "installables.hh"
#include "flake/flake.hh"
namespace nix {
struct PackageInfo;
struct SourceExprCommand;
namespace eval_cache { class EvalCache; class AttrCursor; }
struct App
{
std::vector<DerivedPath> context;
Path program;
// FIXME: add args, sandbox settings, metadata, ...
};
struct UnresolvedApp
{
App unresolved;
App resolve(ref<Store> evalStore, ref<Store> store);
};
/**
* Extra info about a \ref DerivedPath "derived path" that ultimately
* come from a Nix language value.
*
* Invariant: every ExtraPathInfo gotten from an InstallableValue should
* be possible to downcast to an ExtraPathInfoValue.
*/
struct ExtraPathInfoValue : ExtraPathInfo
{
/**
* Extra struct to get around C++ designated initializer limitations
*/
struct Value {
/**
* An optional priority for use with "build envs". See Package
*/
std::optional<NixInt> priority;
/**
* The attribute path associated with this value. The idea is
* that an installable referring to a value typically refers to
* a larger value, from which we project a smaller value out
* with this.
*/
std::string attrPath;
/**
* \todo merge with DerivedPath's 'outputs' field?
*/
ExtendedOutputsSpec extendedOutputsSpec;
};
Value value;
ExtraPathInfoValue(Value && v)
: value(v)
{ }
virtual ~ExtraPathInfoValue() = default;
};
/**
* An Installable which corresponds a Nix langauge value, in addition to
* a collection of \ref DerivedPath "derived paths".
*/
struct InstallableValue : Installable
{
ref<EvalState> state;
InstallableValue(ref<EvalState> state) : state(state) {}
virtual ~InstallableValue() { }
virtual std::pair<Value *, PosIdx> toValue(EvalState & state) = 0;
/**
* Get a cursor to each value this Installable could refer to.
* However if none exists, throw exception instead of returning
* empty vector.
*/
virtual std::vector<ref<eval_cache::AttrCursor>>
getCursors(EvalState & state);
/**
* Get the first and most preferred cursor this Installable could
* refer to, or throw an exception if none exists.
*/
virtual ref<eval_cache::AttrCursor>
getCursor(EvalState & state);
UnresolvedApp toApp(EvalState & state);
static InstallableValue & require(Installable & installable);
static ref<InstallableValue> require(ref<Installable> installable);
protected:
/**
* Handles either a plain path, or a string with a single string
* context elem in the right format. The latter case is handled by
* `EvalState::coerceToDerivedPath()`; see it for details.
*
* @param v Value that is hopefully a string or path per the above.
*
* @param pos Position of value to aid with diagnostics.
*
* @param errorCtx Arbitrary message for use in potential error message when something is wrong with `v`.
*
* @result A derived path (with empty info, for now) if the value
* matched the above criteria.
*/
std::optional<DerivedPathWithInfo> trySinglePathToDerivedPaths(Value & v, const PosIdx pos, std::string_view errorCtx);
};
}