nix-super/src/nix/env.cc

#include "command.hh"
#include "run.hh"
#include <queue>

using namespace nix;

struct CmdEnv : NixMultiCommand
{
    CmdEnv() : NixMultiCommand("env", RegisterCommand::getCommandsFor({"env"}))
    { }

    std::string description() override
    {
        return "manipulate the process environment";
    }

    Category category() override { return catUtility; }
};

static auto rCmdEnv = registerCommand<CmdEnv>("env");

struct CmdShell : InstallablesCommand, MixEnvironment
{

    using InstallablesCommand::run;

    std::vector<std::string> command = { getEnv("SHELL").value_or("bash") };

    CmdShell()
    {
        addFlag({
            .longName = "command",
            .shortName = 'c',
            .description = "Command and arguments to be executed, defaulting to `$SHELL`",
            .labels = {"command", "args"},
            .handler = {[&](std::vector<std::string> ss) {
                if (ss.empty()) throw UsageError("--command requires at least one argument");
                command = ss;
            }}
        });
    }

    std::string description() override
    {
        return "run a shell in which the specified packages are available";
    }

    std::string doc() override
    {
        return
          #include "shell.md"
          ;
    }

    void run(ref<Store> store, Installables && installables) override
    {
        auto outPaths = Installable::toStorePaths(getEvalStore(), store, Realise::Outputs, OperateOn::Output, installables);

        auto accessor = store->getFSAccessor();

        std::unordered_set<StorePath> done;
        std::queue<StorePath> todo;
        for (auto & path : outPaths) todo.push(path);

        setEnviron();

        std::vector<std::string> pathAdditions;

        while (!todo.empty()) {
            auto path = todo.front();
            todo.pop();
            if (!done.insert(path).second) continue;

            if (true)
                pathAdditions.push_back(store->printStorePath(path) + "/bin");

            auto propPath = accessor->resolveSymlinks(
                CanonPath(store->printStorePath(path)) / "nix-support" / "propagated-user-env-packages");
            if (auto st = accessor->maybeLstat(propPath); st && st->type == SourceAccessor::tRegular) {
                for (auto & p : tokenizeString<Paths>(accessor->readFile(propPath)))
                    todo.push(store->parseStorePath(p));
            }
        }

        auto unixPath = tokenizeString<Strings>(getEnv("PATH").value_or(""), ":");
        unixPath.insert(unixPath.begin(), pathAdditions.begin(), pathAdditions.end());
        auto unixPathString = concatStringsSep(":", unixPath);
        setEnv("PATH", unixPathString.c_str());

        Strings args;
        for (auto & arg : command) args.push_back(arg);

        runProgramInStore(store, UseLookupPath::Use, *command.begin(), args);
    }
};

static auto rCmdShell = registerCommand2<CmdShell>({"env", "shell"});