lix/src/libexpr/get-drvs.cc
John Ericson 197feed51d Clean up DerivationOutput, and headers
1. `DerivationOutput` now as the `std::variant` as a base class. And the
   variants are given hierarchical names under `DerivationOutput`.

   In 8e0d0689be @matthewbauer and I
   didn't know a better idiom, and so we made it a field. But this sort
   of "newtype" is anoying for literals downstream.

   Since then we leaned the base class, inherit the constructors trick,
   e.g. used in `DerivedPath`. Switching to use that makes this more
   ergonomic, and consistent.

2. `store-api.hh` and `derivations.hh` are now independent.

   In bcde5456cc I swapped the dependency,
   but I now know it is better to just keep on using incomplete types as
   much as possible for faster compilation and good separation of
   concerns.
2022-03-17 22:35:53 +00:00

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#include "get-drvs.hh"
#include "util.hh"
#include "eval-inline.hh"
#include "derivations.hh"
#include "store-api.hh"
#include "path-with-outputs.hh"
#include <cstring>
#include <regex>
namespace nix {
DrvInfo::DrvInfo(EvalState & state, std::string attrPath, Bindings * attrs)
: state(&state), attrs(attrs), attrPath(std::move(attrPath))
{
}
DrvInfo::DrvInfo(EvalState & state, ref<Store> store, const std::string & drvPathWithOutputs)
: state(&state), attrs(nullptr), attrPath("")
{
auto [drvPath, selectedOutputs] = parsePathWithOutputs(*store, drvPathWithOutputs);
this->drvPath = drvPath;
auto drv = store->derivationFromPath(drvPath);
name = drvPath.name();
if (selectedOutputs.size() > 1)
throw Error("building more than one derivation output is not supported, in '%s'", drvPathWithOutputs);
outputName =
selectedOutputs.empty()
? get(drv.env, "outputName").value_or("out")
: *selectedOutputs.begin();
auto i = drv.outputs.find(outputName);
if (i == drv.outputs.end())
throw Error("derivation '%s' does not have output '%s'", store->printStorePath(drvPath), outputName);
auto & [outputName, output] = *i;
outPath = {output.path(*store, drv.name, outputName)};
}
std::string DrvInfo::queryName() const
{
if (name == "" && attrs) {
auto i = attrs->find(state->sName);
if (i == attrs->end()) throw TypeError("derivation name missing");
name = state->forceStringNoCtx(*i->value);
}
return name;
}
std::string DrvInfo::querySystem() const
{
if (system == "" && attrs) {
auto i = attrs->find(state->sSystem);
system = i == attrs->end() ? "unknown" : state->forceStringNoCtx(*i->value, *i->pos);
}
return system;
}
std::optional<StorePath> DrvInfo::queryDrvPath() const
{
if (!drvPath && attrs) {
Bindings::iterator i = attrs->find(state->sDrvPath);
PathSet context;
if (i == attrs->end())
drvPath = {std::nullopt};
else
drvPath = {state->coerceToStorePath(*i->pos, *i->value, context)};
}
return drvPath.value_or(std::nullopt);
}
StorePath DrvInfo::requireDrvPath() const
{
if (auto drvPath = queryDrvPath())
return *drvPath;
throw Error("derivation does not contain a 'drvPath' attribute");
}
StorePath DrvInfo::queryOutPath() const
{
if (!outPath && attrs) {
Bindings::iterator i = attrs->find(state->sOutPath);
PathSet context;
if (i != attrs->end())
outPath = state->coerceToStorePath(*i->pos, *i->value, context);
}
if (!outPath)
throw UnimplementedError("CA derivations are not yet supported");
return *outPath;
}
DrvInfo::Outputs DrvInfo::queryOutputs(bool withPaths, bool onlyOutputsToInstall)
{
if (outputs.empty()) {
/* Get the outputs list. */
Bindings::iterator i;
if (attrs && (i = attrs->find(state->sOutputs)) != attrs->end()) {
state->forceList(*i->value, *i->pos);
/* For each output... */
for (auto elem : i->value->listItems()) {
std::string output(state->forceStringNoCtx(*elem, *i->pos));
if (withPaths) {
/* Evaluate the corresponding set. */
Bindings::iterator out = attrs->find(state->symbols.create(output));
if (out == attrs->end()) continue; // FIXME: throw error?
state->forceAttrs(*out->value, *i->pos);
/* And evaluate its outPath attribute. */
Bindings::iterator outPath = out->value->attrs->find(state->sOutPath);
if (outPath == out->value->attrs->end()) continue; // FIXME: throw error?
PathSet context;
outputs.emplace(output, state->coerceToStorePath(*outPath->pos, *outPath->value, context));
} else
outputs.emplace(output, std::nullopt);
}
} else
outputs.emplace("out", withPaths ? std::optional{queryOutPath()} : std::nullopt);
}
if (!onlyOutputsToInstall || !attrs)
return outputs;
/* Check for `meta.outputsToInstall` and return `outputs` reduced to that. */
const Value * outTI = queryMeta("outputsToInstall");
if (!outTI) return outputs;
const auto errMsg = Error("this derivation has bad 'meta.outputsToInstall'");
/* ^ this shows during `nix-env -i` right under the bad derivation */
if (!outTI->isList()) throw errMsg;
Outputs result;
for (auto elem : outTI->listItems()) {
if (elem->type() != nString) throw errMsg;
auto out = outputs.find(elem->string.s);
if (out == outputs.end()) throw errMsg;
result.insert(*out);
}
return result;
}
std::string DrvInfo::queryOutputName() const
{
if (outputName == "" && attrs) {
Bindings::iterator i = attrs->find(state->sOutputName);
outputName = i != attrs->end() ? state->forceStringNoCtx(*i->value) : "";
}
return outputName;
}
Bindings * DrvInfo::getMeta()
{
if (meta) return meta;
if (!attrs) return 0;
Bindings::iterator a = attrs->find(state->sMeta);
if (a == attrs->end()) return 0;
state->forceAttrs(*a->value, *a->pos);
meta = a->value->attrs;
return meta;
}
StringSet DrvInfo::queryMetaNames()
{
StringSet res;
if (!getMeta()) return res;
for (auto & i : *meta)
res.insert(i.name);
return res;
}
bool DrvInfo::checkMeta(Value & v)
{
state->forceValue(v, [&]() { return v.determinePos(noPos); });
if (v.type() == nList) {
for (auto elem : v.listItems())
if (!checkMeta(*elem)) return false;
return true;
}
else if (v.type() == nAttrs) {
Bindings::iterator i = v.attrs->find(state->sOutPath);
if (i != v.attrs->end()) return false;
for (auto & i : *v.attrs)
if (!checkMeta(*i.value)) return false;
return true;
}
else return v.type() == nInt || v.type() == nBool || v.type() == nString ||
v.type() == nFloat;
}
Value * DrvInfo::queryMeta(const std::string & name)
{
if (!getMeta()) return 0;
Bindings::iterator a = meta->find(state->symbols.create(name));
if (a == meta->end() || !checkMeta(*a->value)) return 0;
return a->value;
}
std::string DrvInfo::queryMetaString(const std::string & name)
{
Value * v = queryMeta(name);
if (!v || v->type() != nString) return "";
return v->string.s;
}
NixInt DrvInfo::queryMetaInt(const std::string & name, NixInt def)
{
Value * v = queryMeta(name);
if (!v) return def;
if (v->type() == nInt) return v->integer;
if (v->type() == nString) {
/* Backwards compatibility with before we had support for
integer meta fields. */
if (auto n = string2Int<NixInt>(v->string.s))
return *n;
}
return def;
}
NixFloat DrvInfo::queryMetaFloat(const std::string & name, NixFloat def)
{
Value * v = queryMeta(name);
if (!v) return def;
if (v->type() == nFloat) return v->fpoint;
if (v->type() == nString) {
/* Backwards compatibility with before we had support for
float meta fields. */
if (auto n = string2Float<NixFloat>(v->string.s))
return *n;
}
return def;
}
bool DrvInfo::queryMetaBool(const std::string & name, bool def)
{
Value * v = queryMeta(name);
if (!v) return def;
if (v->type() == nBool) return v->boolean;
if (v->type() == nString) {
/* Backwards compatibility with before we had support for
Boolean meta fields. */
if (strcmp(v->string.s, "true") == 0) return true;
if (strcmp(v->string.s, "false") == 0) return false;
}
return def;
}
void DrvInfo::setMeta(const std::string & name, Value * v)
{
getMeta();
auto attrs = state->buildBindings(1 + (meta ? meta->size() : 0));
Symbol sym = state->symbols.create(name);
if (meta)
for (auto i : *meta)
if (i.name != sym)
attrs.insert(i);
if (v) attrs.insert(sym, v);
meta = attrs.finish();
}
/* Cache for already considered attrsets. */
typedef std::set<Bindings *> Done;
/* Evaluate value `v'. If it evaluates to a set of type `derivation',
then put information about it in `drvs' (unless it's already in `done').
The result boolean indicates whether it makes sense
for the caller to recursively search for derivations in `v'. */
static bool getDerivation(EvalState & state, Value & v,
const std::string & attrPath, DrvInfos & drvs, Done & done,
bool ignoreAssertionFailures)
{
try {
state.forceValue(v, [&]() { return v.determinePos(noPos); });
if (!state.isDerivation(v)) return true;
/* Remove spurious duplicates (e.g., a set like `rec { x =
derivation {...}; y = x;}'. */
if (!done.insert(v.attrs).second) return false;
DrvInfo drv(state, attrPath, v.attrs);
drv.queryName();
drvs.push_back(drv);
return false;
} catch (AssertionError & e) {
if (ignoreAssertionFailures) return false;
throw;
}
}
std::optional<DrvInfo> getDerivation(EvalState & state, Value & v,
bool ignoreAssertionFailures)
{
Done done;
DrvInfos drvs;
getDerivation(state, v, "", drvs, done, ignoreAssertionFailures);
if (drvs.size() != 1) return {};
return std::move(drvs.front());
}
static std::string addToPath(const std::string & s1, const std::string & s2)
{
return s1.empty() ? s2 : s1 + "." + s2;
}
static std::regex attrRegex("[A-Za-z_][A-Za-z0-9-_+]*");
static void getDerivations(EvalState & state, Value & vIn,
const std::string & pathPrefix, Bindings & autoArgs,
DrvInfos & drvs, Done & done,
bool ignoreAssertionFailures)
{
Value v;
state.autoCallFunction(autoArgs, vIn, v);
/* Process the expression. */
if (!getDerivation(state, v, pathPrefix, drvs, done, ignoreAssertionFailures)) ;
else if (v.type() == nAttrs) {
/* !!! undocumented hackery to support combining channels in
nix-env.cc. */
bool combineChannels = v.attrs->find(state.symbols.create("_combineChannels")) != v.attrs->end();
/* Consider the attributes in sorted order to get more
deterministic behaviour in nix-env operations (e.g. when
there are names clashes between derivations, the derivation
bound to the attribute with the "lower" name should take
precedence). */
for (auto & i : v.attrs->lexicographicOrder()) {
debug("evaluating attribute '%1%'", i->name);
if (!std::regex_match(std::string(i->name), attrRegex))
continue;
std::string pathPrefix2 = addToPath(pathPrefix, i->name);
if (combineChannels)
getDerivations(state, *i->value, pathPrefix2, autoArgs, drvs, done, ignoreAssertionFailures);
else if (getDerivation(state, *i->value, pathPrefix2, drvs, done, ignoreAssertionFailures)) {
/* If the value of this attribute is itself a set,
should we recurse into it? => Only if it has a
`recurseForDerivations = true' attribute. */
if (i->value->type() == nAttrs) {
Bindings::iterator j = i->value->attrs->find(state.sRecurseForDerivations);
if (j != i->value->attrs->end() && state.forceBool(*j->value, *j->pos))
getDerivations(state, *i->value, pathPrefix2, autoArgs, drvs, done, ignoreAssertionFailures);
}
}
}
}
else if (v.type() == nList) {
for (auto [n, elem] : enumerate(v.listItems())) {
std::string pathPrefix2 = addToPath(pathPrefix, fmt("%d", n));
if (getDerivation(state, *elem, pathPrefix2, drvs, done, ignoreAssertionFailures))
getDerivations(state, *elem, pathPrefix2, autoArgs, drvs, done, ignoreAssertionFailures);
}
}
else throw TypeError("expression does not evaluate to a derivation (or a set or list of those)");
}
void getDerivations(EvalState & state, Value & v, const std::string & pathPrefix,
Bindings & autoArgs, DrvInfos & drvs, bool ignoreAssertionFailures)
{
Done done;
getDerivations(state, v, pathPrefix, autoArgs, drvs, done, ignoreAssertionFailures);
}
}