diff options
| -rw-r--r-- | src/libexpr/primops/context.cc | 59 | ||||
| -rw-r--r-- | tests/lang/eval-okay-context-introspection.nix | 6 |
2 files changed, 61 insertions, 4 deletions
diff --git a/src/libexpr/primops/context.cc b/src/libexpr/primops/context.cc index 6849aa261190..2d79739ea047 100644 --- a/src/libexpr/primops/context.cc +++ b/src/libexpr/primops/context.cc @@ -1,5 +1,6 @@ #include "primops.hh" #include "eval-inline.hh" +#include "derivations.hh" namespace nix { @@ -61,8 +62,7 @@ static RegisterPrimOp r3("__unsafeDiscardOutputDependency", 1, prim_unsafeDiscar (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, but at least one must be set to something other - than the default. + may be present. */ static void prim_getContext(EvalState & state, const Pos & pos, Value * * args, Value & v) { @@ -129,4 +129,59 @@ static void prim_getContext(EvalState & state, const Pos & pos, Value * * args, static RegisterPrimOp r4("__getContext", 1, 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 Pos & pos, Value * * args, Value & v) +{ + PathSet context; + auto orig = state.forceString(*args[0], context, pos); + + state.forceAttrs(*args[1], pos); + + auto sPath = state.symbols.create("path"); + auto sAllOutputs = state.symbols.create("allOutputs"); + for (auto & i : *args[1]->attrs) { + if (!state.store->isStorePath(i.name)) + throw EvalError("Context key '%s' is not a store path, at %s", i.name, i.pos); + if (!settings.readOnlyMode) + state.store->ensurePath(i.name); + state.forceAttrs(*i.value, *i.pos); + auto iter = i.value->attrs->find(sPath); + if (iter != i.value->attrs->end()) { + if (state.forceBool(*iter->value, *iter->pos)) + context.insert(i.name); + } + + iter = i.value->attrs->find(sAllOutputs); + if (iter != i.value->attrs->end()) { + if (state.forceBool(*iter->value, *iter->pos)) { + if (!isDerivation(i.name)) { + throw EvalError("Tried to add all-outputs context of %s, which is not a derivation, to a string, at %s", i.name, i.pos); + } + context.insert("=" + string(i.name)); + } + } + + iter = i.value->attrs->find(state.sOutputs); + if (iter != i.value->attrs->end()) { + state.forceList(*iter->value, *iter->pos); + if (iter->value->listSize() && !isDerivation(i.name)) { + throw EvalError("Tried to add derivation output context of %s, which is not a derivation, to a string, at %s", i.name, i.pos); + } + for (unsigned int n = 0; n < iter->value->listSize(); ++n) { + auto name = state.forceStringNoCtx(*iter->value->listElems()[n], *iter->pos); + context.insert("!" + name + "!" + string(i.name)); + } + } + } + + mkString(v, orig, context); +} + +static RegisterPrimOp r5("__appendContext", 2, prim_appendContext); + } diff --git a/tests/lang/eval-okay-context-introspection.nix b/tests/lang/eval-okay-context-introspection.nix index d9b2ea354990..43178bd2eef9 100644 --- a/tests/lang/eval-okay-context-introspection.nix +++ b/tests/lang/eval-okay-context-introspection.nix @@ -18,5 +18,7 @@ let }; }; - legit-context = "${path}${drv.outPath}${drv.foo.outPath}${drv.drvPath}"; -in builtins.getContext legit-context == desired-context + legit-context = builtins.getContext "${path}${drv.outPath}${drv.foo.outPath}${drv.drvPath}"; + + constructed-context = builtins.getContext (builtins.appendContext "" desired-context); +in legit-context == constructed-context |