nix-super/src/libstore/fetchers/git.cc
2020-02-01 23:54:20 +01:00

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#include "fetchers.hh"
#include "parse.hh"
#include "globals.hh"
#include "tarfile.hh"
#include "store-api.hh"
#include "regex.hh"
#include <sys/time.h>
#include <nlohmann/json.hpp>
using namespace std::string_literals;
namespace nix::fetchers {
static Path getCacheInfoPathFor(const std::string & name, const Hash & rev)
{
Path cacheDir = getCacheDir() + "/nix/git-revs-v2";
std::string linkName =
name == "source"
? rev.gitRev()
: hashString(htSHA512, name + std::string("\0"s) + rev.gitRev()).to_string(Base32, false);
return cacheDir + "/" + linkName + ".link";
}
static void cacheGitInfo(
Store & store,
const std::string & name,
const Tree & tree,
const Hash & rev)
{
nlohmann::json json;
json["storePath"] = store.printStorePath(tree.storePath);
json["name"] = name;
json["rev"] = rev.gitRev();
json["revCount"] = *tree.info.revCount;
json["lastModified"] = *tree.info.lastModified;
auto cacheInfoPath = getCacheInfoPathFor(name, rev);
createDirs(dirOf(cacheInfoPath));
writeFile(cacheInfoPath, json.dump());
}
static std::optional<std::pair<Hash, Tree>> lookupGitInfo(
ref<Store> store,
const std::string & name,
const Hash & rev)
{
try {
auto json = nlohmann::json::parse(readFile(getCacheInfoPathFor(name, rev)));
assert(json["name"] == name && Hash((std::string) json["rev"], htSHA1) == rev);
auto storePath = store->parseStorePath((std::string) json["storePath"]);
if (store->isValidPath(storePath)) {
return {{rev, Tree{
.actualPath = store->toRealPath(store->printStorePath(storePath)),
.storePath = std::move(storePath),
.info = TreeInfo {
.revCount = json["revCount"],
.lastModified = json["lastModified"],
}
}}};
}
} catch (SysError & e) {
if (e.errNo != ENOENT) throw;
}
return {};
}
struct GitInput : Input
{
ParsedURL url;
std::optional<std::string> ref;
std::optional<Hash> rev;
GitInput(const ParsedURL & url) : url(url)
{ }
std::string type() const override { return "git"; }
bool operator ==(const Input & other) const override
{
auto other2 = dynamic_cast<const GitInput *>(&other);
return
other2
&& url == other2->url
&& rev == other2->rev
&& ref == other2->ref;
}
bool isImmutable() const override
{
return (bool) rev;
}
std::optional<std::string> getRef() const override { return ref; }
std::optional<Hash> getRev() const override { return rev; }
std::string to_string() const override
{
ParsedURL url2(url);
if (rev) url2.query.insert_or_assign("rev", rev->gitRev());
if (ref) url2.query.insert_or_assign("ref", *ref);
return url2.to_string();
}
Attrs toAttrsInternal() const override
{
Attrs attrs;
attrs.emplace("url", url.to_string());
if (ref)
attrs.emplace("ref", *ref);
if (rev)
attrs.emplace("rev", rev->gitRev());
return attrs;
}
void clone(const Path & destDir) const override
{
auto [isLocal, actualUrl] = getActualUrl();
Strings args = {"clone"};
args.push_back(actualUrl);
if (ref) {
args.push_back("--branch");
args.push_back(*ref);
}
if (rev) throw Error("cloning a specific revision is not implemented");
args.push_back(destDir);
runProgram("git", true, args);
}
std::shared_ptr<const Input> applyOverrides(
std::optional<std::string> ref,
std::optional<Hash> rev) const override
{
if (!ref && !rev) return shared_from_this();
auto res = std::make_shared<GitInput>(*this);
if (ref) res->ref = ref;
if (rev) res->rev = rev;
if (!res->ref && res->rev)
throw Error("Git input '%s' has a commit hash but no branch/tag name", res->to_string());
return res;
}
std::optional<Path> getSourcePath() const override
{
if (url.scheme == "git+file" && !ref && !rev)
return url.path;
return {};
}
std::pair<bool, std::string> getActualUrl() const
{
// Don't clone git+file:// URIs (but otherwise treat them the
// same as remote URIs, i.e. don't use the working tree or
// HEAD).
static bool forceHttp = getEnv("_NIX_FORCE_HTTP") == "1"; // for testing
bool isLocal = url.scheme == "git+file" && !forceHttp;
return {isLocal, isLocal ? url.path : std::string(url.base, 4)};
}
std::pair<Tree, std::shared_ptr<const Input>> fetchTreeInternal(nix::ref<Store> store) const override
{
auto name = "source";
auto input = std::make_shared<GitInput>(*this);
assert(!rev || rev->type == htSHA1);
if (rev) {
if (auto tree = lookupGitInfo(store, name, *rev)) {
input->rev = tree->first;
return {std::move(tree->second), input};
}
}
auto [isLocal, actualUrl_] = getActualUrl();
auto actualUrl = actualUrl_; // work around clang bug
// If this is a local directory and no ref or revision is
// given, then allow the use of an unclean working tree.
if (!input->ref && !input->rev && isLocal) {
bool clean = false;
/* Check whether this repo has any commits. There are
probably better ways to do this. */
bool haveCommits = !readDirectory(actualUrl + "/.git/refs/heads").empty();
try {
if (haveCommits) {
runProgram("git", true, { "-C", actualUrl, "diff-index", "--quiet", "HEAD", "--" });
clean = true;
}
} catch (ExecError & e) {
if (!WIFEXITED(e.status) || WEXITSTATUS(e.status) != 1) throw;
}
if (!clean) {
/* This is an unclean working tree. So copy all tracked files. */
if (!settings.allowDirty)
throw Error("Git tree '%s' is dirty", actualUrl);
if (settings.warnDirty)
warn("Git tree '%s' is dirty", actualUrl);
auto files = tokenizeString<std::set<std::string>>(
runProgram("git", true, { "-C", actualUrl, "ls-files", "-z" }), "\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, true, htSHA256, filter);
auto tree = Tree {
.actualPath = store->printStorePath(storePath),
.storePath = std::move(storePath),
.info = TreeInfo {
.revCount = haveCommits ? std::stoull(runProgram("git", true, { "-C", actualUrl, "rev-list", "--count", "HEAD" })) : 0,
// FIXME: maybe we should use the timestamp of the last
// modified dirty file?
.lastModified = haveCommits ? std::stoull(runProgram("git", true, { "-C", actualUrl, "log", "-1", "--format=%ct", "HEAD" })) : 0,
}
};
return {std::move(tree), input};
}
}
if (!input->ref) input->ref = isLocal ? "HEAD" : "master";
Path repoDir;
if (isLocal) {
if (!input->rev)
input->rev = Hash(chomp(runProgram("git", true, { "-C", actualUrl, "rev-parse", *input->ref })), htSHA1);
repoDir = actualUrl;
} else {
Path cacheDir = getCacheDir() + "/nix/gitv3/" + hashString(htSHA256, actualUrl).to_string(Base32, false);
repoDir = cacheDir;
if (!pathExists(cacheDir)) {
createDirs(dirOf(cacheDir));
runProgram("git", true, { "init", "--bare", repoDir });
}
Path localRefFile =
input->ref->compare(0, 5, "refs/") == 0
? cacheDir + "/" + *input->ref
: cacheDir + "/refs/heads/" + *input->ref;
bool doFetch;
time_t now = time(0);
/* If a rev was specified, we need to fetch if it's not in the
repo. */
if (input->rev) {
try {
runProgram("git", true, { "-C", repoDir, "cat-file", "-e", input->rev->gitRev() });
doFetch = false;
} catch (ExecError & e) {
if (WIFEXITED(e.status)) {
doFetch = true;
} else {
throw;
}
}
} else {
/* If the local ref is older than tarball-ttl seconds, do a
git fetch to update the local ref to the remote ref. */
struct stat st;
doFetch = stat(localRefFile.c_str(), &st) != 0 ||
(uint64_t) st.st_mtime + settings.tarballTtl <= (uint64_t) now;
}
if (doFetch) {
Activity act(*logger, lvlTalkative, actUnknown, fmt("fetching Git repository '%s'", actualUrl));
// FIXME: git stderr messes up our progress indicator, so
// we're using --quiet for now. Should process its stderr.
try {
runProgram("git", true, { "-C", repoDir, "fetch", "--quiet", "--force", "--", actualUrl, fmt("%s:%s", *input->ref, *input->ref) });
} catch (Error & e) {
if (!pathExists(localRefFile)) throw;
warn("could not update local clone of Git repository '%s'; continuing with the most recent version", actualUrl);
}
struct timeval times[2];
times[0].tv_sec = now;
times[0].tv_usec = 0;
times[1].tv_sec = now;
times[1].tv_usec = 0;
utimes(localRefFile.c_str(), times);
}
if (!input->rev)
input->rev = Hash(chomp(readFile(localRefFile)), htSHA1);
}
if (auto tree = lookupGitInfo(store, name, *input->rev)) {
assert(*input->rev == tree->first);
return {std::move(tree->second), input};
}
// FIXME: check whether rev is an ancestor of ref.
printTalkative("using revision %s of repo '%s'", input->rev->gitRev(), actualUrl);
// FIXME: should pipe this, or find some better way to extract a
// revision.
auto source = sinkToSource([&](Sink & sink) {
RunOptions gitOptions("git", { "-C", repoDir, "archive", input->rev->gitRev() });
gitOptions.standardOut = &sink;
runProgram2(gitOptions);
});
Path tmpDir = createTempDir();
AutoDelete delTmpDir(tmpDir, true);
unpackTarfile(*source, tmpDir);
auto storePath = store->addToStore(name, tmpDir);
auto revCount = std::stoull(runProgram("git", true, { "-C", repoDir, "rev-list", "--count", input->rev->gitRev() }));
auto lastModified = std::stoull(runProgram("git", true, { "-C", repoDir, "log", "-1", "--format=%ct", input->rev->gitRev() }));
auto tree = Tree {
.actualPath = store->toRealPath(store->printStorePath(storePath)),
.storePath = std::move(storePath),
.info = TreeInfo {
.revCount = revCount,
.lastModified = lastModified
}
};
cacheGitInfo(*store, name, tree, *input->rev);
return {std::move(tree), input};
}
};
struct GitInputScheme : InputScheme
{
std::unique_ptr<Input> inputFromURL(const ParsedURL & url) override
{
if (url.scheme != "git" &&
url.scheme != "git+http" &&
url.scheme != "git+https" &&
url.scheme != "git+ssh" &&
url.scheme != "git+file") return nullptr;
auto url2(url);
// FIXME: strip git+
url2.query.clear();
Input::Attrs attrs;
attrs.emplace("type", "git");
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::unique_ptr<Input> inputFromAttrs(const Input::Attrs & attrs) override
{
if (maybeGetStrAttr(attrs, "type") != "git") return {};
for (auto & [name, value] : attrs)
if (name != "type" && name != "url" && name != "ref" && name != "rev")
throw Error("unsupported Git input attribute '%s'", name);
auto input = std::make_unique<GitInput>(parseURL(getStrAttr(attrs, "url")));
if (auto ref = maybeGetStrAttr(attrs, "ref")) {
if (!std::regex_match(*ref, refRegex))
throw BadURL("invalid Git branch/tag name '%s'", *ref);
input->ref = *ref;
}
if (auto rev = maybeGetStrAttr(attrs, "rev"))
input->rev = Hash(*rev, htSHA1);
return input;
}
};
static auto r1 = OnStartup([] { registerInputScheme(std::make_unique<GitInputScheme>()); });
}