path: root/src/libfetchers/mercurial.cc

#include "fetchers.hh"
#include "cache.hh"
#include "globals.hh"
#include "tarfile.hh"
#include "store-api.hh"
#include "url-parts.hh"

#include <sys/time.h>

using namespace std::string_literals;

namespace nix::fetchers {

namespace {

RunOptions hgOptions(const Strings & args) {
	RunOptions opts("hg", args);
	opts.searchPath = true;

	auto env = getEnv();
	// Set HGPLAIN: this means we get consistent output from hg and avoids leakage from a user or system .hgrc.
	env["HGPLAIN"] = "";
	opts.environment = env;

	return opts;
}

// runProgram wrapper that uses hgOptions instead of stock RunOptions.
string runHg(const Strings & args, const std::optional<std::string> & input = {})
{
	RunOptions opts = hgOptions(args);
	opts.input = input;

	auto res = runProgram(opts);

	if (!statusOk(res.first))
		throw ExecError(res.first, fmt("hg %1%", statusToString(res.first)));

	return res.second;
}

}

struct MercurialInputScheme : InputScheme
{
    std::optional<Input> inputFromURL(const ParsedURL & url) override
    {
        if (url.scheme != "hg+http" &&
            url.scheme != "hg+https" &&
            url.scheme != "hg+ssh" &&
            url.scheme != "hg+file") return {};

        auto url2(url);
        url2.scheme = std::string(url2.scheme, 3);
        url2.query.clear();

        Attrs attrs;
        attrs.emplace("type", "hg");

        for (auto &[name, value] : url.query) {
            if (name == "rev" || name == "ref")
                attrs.emplace(name, value);
            else
                url2.query.emplace(name, value);
        }

        attrs.emplace("url", url2.to_string());

        return inputFromAttrs(attrs);
    }

    std::optional<Input> inputFromAttrs(const Attrs & attrs) override
    {
        if (maybeGetStrAttr(attrs, "type") != "hg") return {};

        for (auto & [name, value] : attrs)
            if (name != "type" && name != "url" && name != "ref" && name != "rev" && name != "revCount" && name != "narHash")
                throw Error("unsupported Mercurial input attribute '%s'", name);

        parseURL(getStrAttr(attrs, "url"));

        if (auto ref = maybeGetStrAttr(attrs, "ref")) {
            if (!std::regex_match(*ref, refRegex))
                throw BadURL("invalid Mercurial branch/tag name '%s'", *ref);
        }

        Input input;
        input.attrs = attrs;
        return input;
    }

    ParsedURL toURL(const Input & input) override
    {
        auto url = parseURL(getStrAttr(input.attrs, "url"));
        url.scheme = "hg+" + url.scheme;
        if (auto rev = input.getRev()) url.query.insert_or_assign("rev", rev->gitRev());
        if (auto ref = input.getRef()) url.query.insert_or_assign("ref", *ref);
        return url;
    }

    bool hasAllInfo(const Input & input) override
    {
        // FIXME: ugly, need to distinguish between dirty and clean
        // default trees.
        return input.getRef() == "default" || maybeGetIntAttr(input.attrs, "revCount");
    }

    Input applyOverrides(
        const Input & input,
        std::optional<std::string> ref,
        std::optional<Hash> rev) override
    {
        auto res(input);
        if (rev) res.attrs.insert_or_assign("rev", rev->gitRev());
        if (ref) res.attrs.insert_or_assign("ref", *ref);
        return res;
    }

    std::optional<Path> getSourcePath(const Input & input) override
    {
        auto url = parseURL(getStrAttr(input.attrs, "url"));
        if (url.scheme == "file" && !input.getRef() && !input.getRev())
            return url.path;
        return {};
    }

    void markChangedFile(const Input & input, std::string_view file, std::optional<std::string> commitMsg) override
    {
        auto sourcePath = getSourcePath(input);
        assert(sourcePath);

        // FIXME: shut up if file is already tracked.
        runHg(
            { "add", *sourcePath + "/" + std::string(file) });

        if (commitMsg)
            runHg(
                { "commit", *sourcePath + "/" + std::string(file), "-m", *commitMsg });
    }

    std::pair<bool, std::string> getActualUrl(const Input & input) const
    {
        auto url = parseURL(getStrAttr(input.attrs, "url"));
        bool isLocal = url.scheme == "file";
        return {isLocal, isLocal ? url.path : url.base};
    }

    std::pair<Tree, Input> fetch(ref<Store> store, const Input & _input) override
    {
        auto name = "source";

        Input input(_input);

        auto [isLocal, actualUrl_] = getActualUrl(input);
        auto actualUrl = actualUrl_; // work around clang bug

        // FIXME: return lastModified.

        // FIXME: don't clone local repositories.

        if (!input.getRef() && !input.getRev() && isLocal && pathExists(actualUrl + "/.hg")) {

            bool clean = runHg({ "status", "-R", actualUrl, "--modified", "--added", "--removed" }) == "";

            if (!clean) {

                /* This is an unclean working tree. So copy all tracked
                   files. */

                if (!settings.allowDirty)
                    throw Error("Mercurial tree '%s' is unclean", actualUrl);

                if (settings.warnDirty)
                    warn("Mercurial tree '%s' is unclean", actualUrl);

                input.attrs.insert_or_assign("ref", chomp(runHg({ "branch", "-R", actualUrl })));

                auto files = tokenizeString<std::set<std::string>>(
                    runHg({ "status", "-R", actualUrl, "--clean", "--modified", "--added", "--no-status", "--print0" }), "\0"s);

                PathFilter filter = [&](const Path & p) -> bool {
                    assert(hasPrefix(p, actualUrl));
                    std::string file(p, actualUrl.size() + 1);

                    auto st = lstat(p);

                    if (S_ISDIR(st.st_mode)) {
                        auto prefix = file + "/";
                        auto i = files.lower_bound(prefix);
                        return i != files.end() && hasPrefix(*i, prefix);
                    }

                    return files.count(file);
                };

                auto storePath = store->addToStore("source", actualUrl, FileIngestionMethod::Recursive, htSHA256, filter);

                return {
                    Tree(store->toRealPath(storePath), std::move(storePath)),
                    input
                };
            }
        }

        if (!input.getRef()) input.attrs.insert_or_assign("ref", "default");

        auto getImmutableAttrs = [&]()
        {
            return Attrs({
                {"type", "hg"},