nix-super/src/nix-instantiate/nix-instantiate.cc
pennae 8775be3393 store Symbols in a table as well, like positions
this slightly increases the amount of memory used for any given symbol, but this
increase is more than made up for if the symbol is referenced more than once in
the EvalState that holds it. on average every symbol should be referenced at
least twice (once to introduce a binding, once to use it), so we expect no
increase in memory on average.

symbol tables are limited to 2³² entries like position tables, and similar
arguments apply to why overflow is not likely: 2³² symbols would require as many
string instances (at 24 bytes each) and map entries (at 24 bytes or more each,
assuming that the map holds on average at most one item per bucket as the docs
say). a full symbol table would require at least 192GB of memory just for
symbols, which is well out of reach. (an ofborg eval of nixpks today creates
less than a million symbols!)
2022-04-21 21:56:31 +02:00

198 lines
6.5 KiB
C++

#include "globals.hh"
#include "shared.hh"
#include "eval.hh"
#include "eval-inline.hh"
#include "get-drvs.hh"
#include "attr-path.hh"
#include "value-to-xml.hh"
#include "value-to-json.hh"
#include "util.hh"
#include "store-api.hh"
#include "local-fs-store.hh"
#include "common-eval-args.hh"
#include "legacy.hh"
#include <map>
#include <iostream>
using namespace nix;
static Path gcRoot;
static int rootNr = 0;
enum OutputKind { okPlain, okXML, okJSON };
void processExpr(EvalState & state, const Strings & attrPaths,
bool parseOnly, bool strict, Bindings & autoArgs,
bool evalOnly, OutputKind output, bool location, Expr * e)
{
if (parseOnly) {
e->show(state.symbols, std::cout);
std::cout << "\n";
return;
}
Value vRoot;
state.eval(e, vRoot);
for (auto & i : attrPaths) {
Value & v(*findAlongAttrPath(state, i, autoArgs, vRoot).first);
state.forceValue(v, [&]() { return v.determinePos(noPos); });
PathSet context;
if (evalOnly) {
Value vRes;
if (autoArgs.empty())
vRes = v;
else
state.autoCallFunction(autoArgs, v, vRes);
if (output == okXML)
printValueAsXML(state, strict, location, vRes, std::cout, context, noPos);
else if (output == okJSON)
printValueAsJSON(state, strict, vRes, v.determinePos(noPos), std::cout, context);
else {
if (strict) state.forceValueDeep(vRes);
vRes.print(state.symbols, std::cout);
std::cout << std::endl;
}
} else {
DrvInfos drvs;
getDerivations(state, v, "", autoArgs, drvs, false);
for (auto & i : drvs) {
auto drvPath = i.requireDrvPath();
auto drvPathS = state.store->printStorePath(drvPath);
/* What output do we want? */
std::string outputName = i.queryOutputName();
if (outputName == "")
throw Error("derivation '%1%' lacks an 'outputName' attribute", drvPathS);
if (gcRoot == "")
printGCWarning();
else {
Path rootName = absPath(gcRoot);
if (++rootNr > 1) rootName += "-" + std::to_string(rootNr);
auto store2 = state.store.dynamic_pointer_cast<LocalFSStore>();
if (store2)
drvPathS = store2->addPermRoot(drvPath, rootName);
}
std::cout << fmt("%s%s\n", drvPathS, (outputName != "out" ? "!" + outputName : ""));
}
}
}
}
static int main_nix_instantiate(int argc, char * * argv)
{
{
Strings files;
bool readStdin = false;
bool fromArgs = false;
bool findFile = false;
bool evalOnly = false;
bool parseOnly = false;
OutputKind outputKind = okPlain;
bool xmlOutputSourceLocation = true;
bool strict = false;
Strings attrPaths;
bool wantsReadWrite = false;
RepairFlag repair = NoRepair;
struct MyArgs : LegacyArgs, MixEvalArgs
{
using LegacyArgs::LegacyArgs;
};
MyArgs myArgs(std::string(baseNameOf(argv[0])), [&](Strings::iterator & arg, const Strings::iterator & end) {
if (*arg == "--help")
showManPage("nix-instantiate");
else if (*arg == "--version")
printVersion("nix-instantiate");
else if (*arg == "-")
readStdin = true;
else if (*arg == "--expr" || *arg == "-E")
fromArgs = true;
else if (*arg == "--eval" || *arg == "--eval-only")
evalOnly = true;
else if (*arg == "--read-write-mode")
wantsReadWrite = true;
else if (*arg == "--parse" || *arg == "--parse-only")
parseOnly = evalOnly = true;
else if (*arg == "--find-file")
findFile = true;
else if (*arg == "--attr" || *arg == "-A")
attrPaths.push_back(getArg(*arg, arg, end));
else if (*arg == "--add-root")
gcRoot = getArg(*arg, arg, end);
else if (*arg == "--indirect")
;
else if (*arg == "--xml")
outputKind = okXML;
else if (*arg == "--json")
outputKind = okJSON;
else if (*arg == "--no-location")
xmlOutputSourceLocation = false;
else if (*arg == "--strict")
strict = true;
else if (*arg == "--repair")
repair = Repair;
else if (*arg == "--dry-run")
settings.readOnlyMode = true;
else if (*arg != "" && arg->at(0) == '-')
return false;
else
files.push_back(*arg);
return true;
});
myArgs.parseCmdline(argvToStrings(argc, argv));
if (evalOnly && !wantsReadWrite)
settings.readOnlyMode = true;
auto store = openStore();
auto evalStore = myArgs.evalStoreUrl ? openStore(*myArgs.evalStoreUrl) : store;
auto state = std::make_unique<EvalState>(myArgs.searchPath, evalStore, store);
state->repair = repair;
Bindings & autoArgs = *myArgs.getAutoArgs(*state);
if (attrPaths.empty()) attrPaths = {""};
if (findFile) {
for (auto & i : files) {
Path p = state->findFile(i);
if (p == "") throw Error("unable to find '%1%'", i);
std::cout << p << std::endl;
}
return 0;
}
if (readStdin) {
Expr * e = state->parseStdin();
processExpr(*state, attrPaths, parseOnly, strict, autoArgs,
evalOnly, outputKind, xmlOutputSourceLocation, e);
} else if (files.empty() && !fromArgs)
files.push_back("./default.nix");
for (auto & i : files) {
Expr * e = fromArgs
? state->parseExprFromString(i, absPath("."))
: state->parseExprFromFile(resolveExprPath(state->checkSourcePath(lookupFileArg(*state, i))));
processExpr(*state, attrPaths, parseOnly, strict, autoArgs,
evalOnly, outputKind, xmlOutputSourceLocation, e);
}
state->printStats();
return 0;
}
}
static RegisterLegacyCommand r_nix_instantiate("nix-instantiate", main_nix_instantiate);