nix-super/src/nix/build.cc
John Ericson 242f9bf3dc std::visit by reference
I had started the trend of doing `std::visit` by value (because a type
error once mislead me into thinking that was the only form that
existed). While the optomizer in principle should be able to deal with
extra coppying or extra indirection once the lambdas inlined, sticking
with by reference is the conventional default. I hope this might even
improve performance.
2021-09-30 21:35:09 +00:00

89 lines
2.8 KiB
C++

#include "eval.hh"
#include "command.hh"
#include "common-args.hh"
#include "shared.hh"
#include "store-api.hh"
#include "local-fs-store.hh"
#include <nlohmann/json.hpp>
using namespace nix;
struct CmdBuild : InstallablesCommand, MixDryRun, MixJSON, MixProfile
{
Path outLink = "result";
BuildMode buildMode = bmNormal;
CmdBuild()
{
addFlag({
.longName = "out-link",
.shortName = 'o',
.description = "Use *path* as prefix for the symlinks to the build results. It defaults to `result`.",
.labels = {"path"},
.handler = {&outLink},
.completer = completePath
});
addFlag({
.longName = "no-link",
.description = "Do not create symlinks to the build results.",
.handler = {&outLink, Path("")},
});
addFlag({
.longName = "rebuild",
.description = "Rebuild an already built package and compare the result to the existing store paths.",
.handler = {&buildMode, bmCheck},
});
}
std::string description() override
{
return "build a derivation or fetch a store path";
}
std::string doc() override
{
return
#include "build.md"
;
}
void run(ref<Store> store) override
{
auto buildables = build(
getEvalStore(), store,
dryRun ? Realise::Derivation : Realise::Outputs,
installables, buildMode);
if (json) logger->cout("%s", derivedPathsWithHintsToJSON(buildables, store).dump());
if (dryRun) return;
if (outLink != "")
if (auto store2 = store.dynamic_pointer_cast<LocalFSStore>())
for (const auto & [_i, buildable] : enumerate(buildables)) {
auto i = _i;
std::visit(overloaded {
[&](const BuiltPath::Opaque & bo) {
std::string symlink = outLink;
if (i) symlink += fmt("-%d", i);
store2->addPermRoot(bo.path, absPath(symlink));
},
[&](const BuiltPath::Built & bfd) {
for (auto & output : bfd.outputs) {
std::string symlink = outLink;
if (i) symlink += fmt("-%d", i);
if (output.first != "out") symlink += fmt("-%s", output.first);
store2->addPermRoot(output.second, absPath(symlink));
}
},
}, buildable.raw());
}
updateProfile(buildables);
}
};
static auto rCmdBuild = registerCommand<CmdBuild>("build");