diff options
author | Eelco Dolstra <edolstra@gmail.com> | 2019-02-12T16·57+0100 |
---|---|---|
committer | GitHub <noreply@github.com> | 2019-02-12T16·57+0100 |
commit | 7a7ec2229834aa294b3e09df7f514b7134287ec2 (patch) | |
tree | 4c704e904b9ed21536ceb39632e61d7c78b2917b /src | |
parent | 01d07b1e92c298f729a73705907b2987da9a4d0c (diff) | |
parent | b30be6b450f872f8be6dc8afa28f4b030fa8d1d1 (diff) |
Merge pull request #2628 from shlevy/context-introspection
Context introspection
Diffstat (limited to 'src')
-rw-r--r-- | src/libexpr/eval.hh | 3 | ||||
-rw-r--r-- | src/libexpr/primops.cc | 56 | ||||
-rw-r--r-- | src/libexpr/primops/context.cc | 187 |
3 files changed, 192 insertions, 54 deletions
diff --git a/src/libexpr/eval.hh b/src/libexpr/eval.hh index d0f298e168e9..9fe3878916d5 100644 --- a/src/libexpr/eval.hh +++ b/src/libexpr/eval.hh @@ -316,6 +316,9 @@ private: /* Return a string representing the type of the value `v'. */ string showType(const Value & v); +/* Decode a context string ‘!<name>!<path>’ into a pair <path, + name>. */ +std::pair<string, string> decodeContext(const string & s); /* If `path' refers to a directory, then append "/default.nix". */ Path resolveExprPath(Path path); diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index 60698f7402e0..0da9f702f4bb 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -687,21 +687,12 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * * } } - /* See prim_unsafeDiscardOutputDependency. */ - else if (path.at(0) == '~') - drv.inputSrcs.insert(string(path, 1)); - /* Handle derivation outputs of the form ‘!<name>!<path>’. */ else if (path.at(0) == '!') { std::pair<string, string> ctx = decodeContext(path); drv.inputDrvs[ctx.first].insert(ctx.second); } - /* Handle derivation contexts returned by - ‘builtins.storePath’. */ - else if (isDerivation(path)) - drv.inputDrvs[path] = state.store->queryDerivationOutputNames(path); - /* Otherwise it's a source file. */ else drv.inputSrcs.insert(path); @@ -1004,13 +995,8 @@ static void prim_toFile(EvalState & state, const Pos & pos, Value * * args, Valu PathSet refs; for (auto path : context) { - if (path.at(0) == '=') path = string(path, 1); - if (isDerivation(path)) { - /* See prim_unsafeDiscardOutputDependency. */ - if (path.at(0) != '~') - throw EvalError(format("in 'toFile': the file '%1%' cannot refer to derivation outputs, at %2%") % name % pos); - path = string(path, 1); - } + if (path.at(0) != '/') + throw EvalError(format("in 'toFile': the file '%1%' cannot refer to derivation outputs, at %2%") % name % pos); refs.insert(path); } @@ -1794,41 +1780,6 @@ static void prim_stringLength(EvalState & state, const Pos & pos, Value * * args } -static void prim_unsafeDiscardStringContext(EvalState & state, const Pos & pos, Value * * args, Value & v) -{ - PathSet context; - string s = state.coerceToString(pos, *args[0], context); - mkString(v, s, PathSet()); -} - - -static void prim_hasContext(EvalState & state, const Pos & pos, Value * * args, Value & v) -{ - PathSet context; - state.forceString(*args[0], context, pos); - mkBool(v, !context.empty()); -} - - -/* 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 Pos & pos, Value * * args, Value & v) -{ - PathSet context; - string s = state.coerceToString(pos, *args[0], context); - - PathSet context2; - for (auto & p : context) - context2.insert(p.at(0) == '=' ? "~" + string(p, 1) : p); - - mkString(v, s, context2); -} - - /* Return the cryptographic hash of a string in base-16. */ static void prim_hashString(EvalState & state, const Pos & pos, Value * * args, Value & v) { @@ -2299,9 +2250,6 @@ void EvalState::createBaseEnv() addPrimOp("toString", 1, prim_toString); addPrimOp("__substring", 3, prim_substring); addPrimOp("__stringLength", 1, prim_stringLength); - addPrimOp("__hasContext", 1, prim_hasContext); - addPrimOp("__unsafeDiscardStringContext", 1, prim_unsafeDiscardStringContext); - addPrimOp("__unsafeDiscardOutputDependency", 1, prim_unsafeDiscardOutputDependency); addPrimOp("__hashString", 2, prim_hashString); addPrimOp("__match", 2, prim_match); addPrimOp("__split", 2, prim_split); diff --git a/src/libexpr/primops/context.cc b/src/libexpr/primops/context.cc new file mode 100644 index 000000000000..2d79739ea047 --- /dev/null +++ b/src/libexpr/primops/context.cc @@ -0,0 +1,187 @@ +#include "primops.hh" +#include "eval-inline.hh" +#include "derivations.hh" + +namespace nix { + +static void prim_unsafeDiscardStringContext(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + string s = state.coerceToString(pos, *args[0], context); + mkString(v, s, PathSet()); +} + +static RegisterPrimOp r1("__unsafeDiscardStringContext", 1, prim_unsafeDiscardStringContext); + + +static void prim_hasContext(EvalState & state, const Pos & pos, Value * * args, Value & v) +{ + PathSet context; + state.forceString(*args[0], context, pos); + mkBool(v, !context.empty()); +} + +static RegisterPrimOp r2("__hasContext", 1, 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 Pos & pos, Value * * args, Value & v) +{ + PathSet context; + string s = state.coerceToString(pos, *args[0], context); + + PathSet context2; + for (auto & p : context) + context2.insert(p.at(0) == '=' ? string(p, 1) : p); + + mkString(v, s, context2); +} + +static RegisterPrimOp r3("__unsafeDiscardOutputDependency", 1, 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 Pos & pos, Value * * args, Value & v) +{ + struct ContextInfo { + bool path = false; + bool allOutputs = false; + Strings outputs; + }; + PathSet context; + state.forceString(*args[0], context, pos); + auto contextInfos = std::map<Path, ContextInfo>(); + for (const auto & p : context) { + Path drv; + string output; + const Path * path = &p; + if (p.at(0) == '=') { + drv = string(p, 1); + path = &drv; + } else if (p.at(0) == '!') { + std::pair<string, string> ctx = decodeContext(p); + drv = ctx.first; + output = ctx.second; + path = &drv; + } + auto isPath = drv.empty(); + auto isAllOutputs = (!drv.empty()) && output.empty(); + + auto iter = contextInfos.find(*path); + if (iter == contextInfos.end()) { + contextInfos.emplace(*path, ContextInfo{isPath, isAllOutputs, output.empty() ? Strings{} : Strings{std::move(output)}}); + } else { + if (isPath) + iter->second.path = true; + else if (isAllOutputs) + iter->second.allOutputs = true; + else + iter->second.outputs.emplace_back(std::move(output)); + } + } + + state.mkAttrs(v, contextInfos.size()); + + auto sPath = state.symbols.create("path"); + auto sAllOutputs = state.symbols.create("allOutputs"); + for (const auto & info : contextInfos) { + auto & infoVal = *state.allocAttr(v, state.symbols.create(info.first)); + state.mkAttrs(infoVal, 3); + if (info.second.path) + mkBool(*state.allocAttr(infoVal, sPath), true); + if (info.second.allOutputs) + mkBool(*state.allocAttr(infoVal, sAllOutputs), true); + if (!info.second.outputs.empty()) { + auto & outputsVal = *state.allocAttr(infoVal, state.sOutputs); + state.mkList(outputsVal, info.second.outputs.size()); + size_t i = 0; + for (const auto & output : info.second.outputs) { + mkString(*(outputsVal.listElems()[i++] = state.allocValue()), output); + } + } + infoVal.attrs->sort(); + } + v.attrs->sort(); +} + +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); + +} |