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#include "primops.hh"
#include "eval-inline.hh"
#include "derivations.hh"
#include "store-api.hh"
namespace nix {
static void prim_unsafeDiscardStringContext(EvalState & state, const PosIdx pos, Value * * args, Value & v)
{
NixStringContext context;
auto s = state.coerceToString(pos, *args[0], context, "while evaluating the argument passed to builtins.unsafeDiscardStringContext");
v.mkString(*s);
}
static RegisterPrimOp primop_unsafeDiscardStringContext({
.name = "__unsafeDiscardStringContext",
.arity = 1,
.fun = prim_unsafeDiscardStringContext
});
static void prim_hasContext(EvalState & state, const PosIdx pos, Value * * args, Value & v)
{
NixStringContext context;
state.forceString(*args[0], context, pos, "while evaluating the argument passed to builtins.hasContext");
v.mkBool(!context.empty());
}
static RegisterPrimOp primop_hasContext({
.name = "__hasContext",
.args = {"s"},
.doc = R"(
Return `true` if string *s* has a non-empty context. The
context can be obtained with
[`getContext`](#builtins-getContext).
)",
.fun = prim_hasContext
});
/* Sometimes we want to pass a derivation path (i.e. pkg.drvPath) to a
builder without causing the derivation to be built (for instance,
in the derivation that builds NARs in nix-push, when doing
source-only deployment). This primop marks the string context so
that builtins.derivation adds the path to drv.inputSrcs rather than
drv.inputDrvs. */
static void prim_unsafeDiscardOutputDependency(EvalState & state, const PosIdx pos, Value * * args, Value & v)
{
NixStringContext context;
auto s = state.coerceToString(pos, *args[0], context, "while evaluating the argument passed to builtins.unsafeDiscardOutputDependency");
NixStringContext context2;
for (auto && c : context) {
if (auto * ptr = std::get_if<NixStringContextElem::DrvDeep>(&c)) {
context2.emplace(NixStringContextElem::Opaque {
.path = ptr->drvPath
});
} else {
/* Can reuse original item */
context2.emplace(std::move(c));
}
}
v.mkString(*s, context2);
}
static RegisterPrimOp primop_unsafeDiscardOutputDependency({
.name = "__unsafeDiscardOutputDependency",
.arity = 1,
.fun = prim_unsafeDiscardOutputDependency
});
/* Extract the context of a string as a structured Nix value.
The context is represented as an attribute set whose keys are the
paths in the context set and whose values are attribute sets with
the following keys:
path: True if the relevant path is in the context as a plain store
path (i.e. the kind of context you get when interpolating
a Nix path (e.g. ./.) into a string). False if missing.
allOutputs: True if the relevant path is a derivation and it is
in the context as a drv file with all of its outputs
(i.e. the kind of context you get when referencing
.drvPath of some derivation). False if missing.
outputs: If a non-empty list, the relevant path is a derivation
and the provided outputs are referenced in the context
(i.e. the kind of context you get when referencing
.outPath of some derivation). Empty list if missing.
Note that for a given path any combination of the above attributes
may be present.
*/
static void prim_getContext(EvalState & state, const PosIdx pos, Value * * args, Value & v)
{
struct ContextInfo {
bool path = false;
bool allOutputs = false;
Strings outputs;
};
NixStringContext context;
state.forceString(*args[0], context, pos, "while evaluating the argument passed to builtins.getContext");
auto contextInfos = std::map<StorePath, ContextInfo>();
for (auto && i : context) {
std::visit(overloaded {
[&](NixStringContextElem::DrvDeep && d) {
contextInfos[std::move(d.drvPath)].allOutputs = true;
},
[&](NixStringContextElem::Built && b) {
contextInfos[std::move(b.drvPath)].outputs.emplace_back(std::move(b.output));
},
[&](NixStringContextElem::Opaque && o) {
contextInfos[std::move(o.path)].path = true;
},
}, ((NixStringContextElem &&) i).raw());
}
auto attrs = state.buildBindings(contextInfos.size());
auto sPath = state.symbols.create("path");
auto sAllOutputs = state.symbols.create("allOutputs");
for (const auto & info : contextInfos) {
auto infoAttrs = state.buildBindings(3);
if (info.second.path)
infoAttrs.alloc(sPath).mkBool(true);
if (info.second.allOutputs)
infoAttrs.alloc(sAllOutputs).mkBool(true);
if (!info.second.outputs.empty()) {
auto & outputsVal = infoAttrs.alloc(state.sOutputs);
state.mkList(outputsVal, info.second.outputs.size());
for (const auto & [i, output] : enumerate(info.second.outputs))
(outputsVal.listElems()[i] = state.allocValue())->mkString(output);
}
attrs.alloc(state.store->printStorePath(info.first)).mkAttrs(infoAttrs);
}
v.mkAttrs(attrs);
}
static RegisterPrimOp primop_getContext({
.name = "__getContext",
.args = {"s"},
.doc = R"(
Return the string context of *s*.
The string context tracks references to derivations within a string.
It is represented as an attribute set of [store derivation](@docroot@/glossary.md#gloss-store-derivation) paths mapping to output names.
Using [string interpolation](@docroot@/language/string-interpolation.md) on a derivation will add that derivation to the string context.
For example,
```nix
builtins.getContext "${derivation { name = "a"; builder = "b"; system = "c"; }}"
```
evaluates to
```
{ "/nix/store/arhvjaf6zmlyn8vh8fgn55rpwnxq0n7l-a.drv" = { outputs = [ "out" ]; }; }
```
)",
.fun = prim_getContext
});
/* Append the given context to a given string.
See the commentary above unsafeGetContext for details of the
context representation.
*/
static void prim_appendContext(EvalState & state, const PosIdx pos, Value * * args, Value & v)
{
NixStringContext context;
auto orig = state.forceString(*args[0], context, noPos, "while evaluating the first argument passed to builtins.appendContext");
state.forceAttrs(*args[1], pos, "while evaluating the second argument passed to builtins.appendContext");
auto sPath = state.symbols.create("path");
auto sAllOutputs = state.symbols.create("allOutputs");
for (auto & i : *args[1]->attrs) {
const auto & name = state.symbols[i.name];
if (!state.store->isStorePath(name))
throw EvalError({
.msg = hintfmt("context key '%s' is not a store path", name),
.errPos = state.positions[i.pos]
});
auto namePath = state.store->parseStorePath(name);
if (!settings.readOnlyMode)
state.store->ensurePath(namePath);
state.forceAttrs(*i.value, i.pos, "while evaluating the value of a string context");
auto iter = i.value->attrs->find(sPath);
if (iter != i.value->attrs->end()) {
if (state.forceBool(*iter->value, iter->pos, "while evaluating the `path` attribute of a string context"))
context.emplace(NixStringContextElem::Opaque {
.path = namePath,
});
}
iter = i.value->attrs->find(sAllOutputs);
if (iter != i.value->attrs->end()) {
if (state.forceBool(*iter->value, iter->pos, "while evaluating the `allOutputs` attribute of a string context")) {
if (!isDerivation(name)) {
throw EvalError({
.msg = hintfmt("tried to add all-outputs context of %s, which is not a derivation, to a string", name),
.errPos = state.positions[i.pos]
});
}
context.emplace(NixStringContextElem::DrvDeep {
.drvPath = namePath,
});
}
}
iter = i.value->attrs->find(state.sOutputs);
if (iter != i.value->attrs->end()) {
state.forceList(*iter->value, iter->pos, "while evaluating the `outputs` attribute of a string context");
if (iter->value->listSize() && !isDerivation(name)) {
throw EvalError({
.msg = hintfmt("tried to add derivation output context of %s, which is not a derivation, to a string", name),
.errPos = state.positions[i.pos]
});
}
for (auto elem : iter->value->listItems()) {
auto outputName = state.forceStringNoCtx(*elem, iter->pos, "while evaluating an output name within a string context");
context.emplace(NixStringContextElem::Built {
.drvPath = namePath,
.output = std::string { outputName },
});
}
}
}
v.mkString(orig, context);
}
static RegisterPrimOp primop_appendContext({
.name = "__appendContext",
.arity = 2,
.fun = prim_appendContext
});
}
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