lix/src/libexpr/primops/fetchMercurial.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

92 lines
3.3 KiB
C++

#include "primops.hh"
#include "eval-inline.hh"
#include "store-api.hh"
#include "fetchers.hh"
#include "url.hh"
#include "url-parts.hh"
namespace nix {
static void prim_fetchMercurial(EvalState & state, const PosIdx pos, Value * * args, Value & v)
{
std::string url;
std::optional<Hash> rev;
std::optional<std::string> ref;
std::string_view name = "source";
PathSet context;
state.forceValue(*args[0], pos);
if (args[0]->type() == nAttrs) {
state.forceAttrs(*args[0], pos);
for (auto & attr : *args[0]->attrs) {
std::string_view n(state.symbols[attr.name]);
if (n == "url")
url = state.coerceToString(attr.pos, *attr.value, context, false, false).toOwned();
else if (n == "rev") {
// Ugly: unlike fetchGit, here the "rev" attribute can
// be both a revision or a branch/tag name.
auto value = state.forceStringNoCtx(*attr.value, attr.pos);
if (std::regex_match(value.begin(), value.end(), revRegex))
rev = Hash::parseAny(value, htSHA1);
else
ref = value;
}
else if (n == "name")
name = state.forceStringNoCtx(*attr.value, attr.pos);
else
throw EvalError({
.msg = hintfmt("unsupported argument '%s' to 'fetchMercurial'", state.symbols[attr.name]),
.errPos = state.positions[attr.pos]
});
}
if (url.empty())
throw EvalError({
.msg = hintfmt("'url' argument required"),
.errPos = state.positions[pos]
});
} else
url = state.coerceToString(pos, *args[0], context, false, false).toOwned();
// FIXME: git externals probably can be used to bypass the URI
// whitelist. Ah well.
state.checkURI(url);
if (evalSettings.pureEval && !rev)
throw Error("in pure evaluation mode, 'fetchMercurial' requires a Mercurial revision");
fetchers::Attrs attrs;
attrs.insert_or_assign("type", "hg");
attrs.insert_or_assign("url", url.find("://") != std::string::npos ? url : "file://" + url);
attrs.insert_or_assign("name", std::string(name));
if (ref) attrs.insert_or_assign("ref", *ref);
if (rev) attrs.insert_or_assign("rev", rev->gitRev());
auto input = fetchers::Input::fromAttrs(std::move(attrs));
// FIXME: use name
auto [tree, input2] = input.fetch(state.store);
auto attrs2 = state.buildBindings(8);
auto storePath = state.store->printStorePath(tree.storePath);
attrs2.alloc(state.sOutPath).mkString(storePath, {storePath});
if (input2.getRef())
attrs2.alloc("branch").mkString(*input2.getRef());
// Backward compatibility: set 'rev' to
// 0000000000000000000000000000000000000000 for a dirty tree.
auto rev2 = input2.getRev().value_or(Hash(htSHA1));
attrs2.alloc("rev").mkString(rev2.gitRev());
attrs2.alloc("shortRev").mkString(rev2.gitRev().substr(0, 12));
if (auto revCount = input2.getRevCount())
attrs2.alloc("revCount").mkInt(*revCount);
v.mkAttrs(attrs2);
state.allowPath(tree.storePath);
}
static RegisterPrimOp r_fetchMercurial("fetchMercurial", 1, prim_fetchMercurial);
}