lix/src/libexpr/flake/lockfile.cc
2020-06-10 15:20:00 +02:00

265 lines
7.5 KiB
C++

#include "lockfile.hh"
#include "store-api.hh"
#include <nlohmann/json.hpp>
namespace nix::flake {
FlakeRef getFlakeRef(
const nlohmann::json & json,
const char * attr,
const char * info)
{
auto i = json.find(attr);
if (i != json.end()) {
auto attrs = jsonToAttrs(*i);
// FIXME: remove when we drop support for version 5.
if (info) {
auto j = json.find(info);
if (j != json.end()) {
for (auto k : jsonToAttrs(*j))
attrs.insert_or_assign(k.first, k.second);
}
}
return FlakeRef::fromAttrs(attrs);
}
throw Error("attribute '%s' missing in lock file", attr);
}
LockedNode::LockedNode(const nlohmann::json & json)
: lockedRef(getFlakeRef(json, "locked", "info"))
, originalRef(getFlakeRef(json, "original", nullptr))
, isFlake(json.find("flake") != json.end() ? (bool) json["flake"] : true)
{
if (!lockedRef.input.isImmutable())
throw Error("lockfile contains mutable lock '%s'", attrsToJson(lockedRef.input.toAttrs()));
}
StorePath LockedNode::computeStorePath(Store & store) const
{
return lockedRef.input.computeStorePath(store);
}
std::shared_ptr<Node> Node::findInput(const InputPath & path)
{
auto pos = shared_from_this();
for (auto & elem : path) {
auto i = pos->inputs.find(elem);
if (i == pos->inputs.end())
return {};
pos = i->second;
}
return pos;
}
LockFile::LockFile(const nlohmann::json & json, const Path & path)
{
auto version = json.value("version", 0);
if (version < 5 || version > 6)
throw Error("lock file '%s' has unsupported version %d", path, version);
std::unordered_map<std::string, std::shared_ptr<Node>> nodeMap;
std::function<void(Node & node, const nlohmann::json & jsonNode)> getInputs;
getInputs = [&](Node & node, const nlohmann::json & jsonNode)
{
if (jsonNode.find("inputs") == jsonNode.end()) return;
for (auto & i : jsonNode["inputs"].items()) {
std::string inputKey = i.value();
auto k = nodeMap.find(inputKey);
if (k == nodeMap.end()) {
auto jsonNode2 = json["nodes"][inputKey];
auto input = std::make_shared<LockedNode>(jsonNode2);
k = nodeMap.insert_or_assign(inputKey, input).first;
getInputs(*input, jsonNode2);
}
node.inputs.insert_or_assign(i.key(), k->second);
}
};
std::string rootKey = json["root"];
nodeMap.insert_or_assign(rootKey, root);
getInputs(*root, json["nodes"][rootKey]);
}
nlohmann::json LockFile::toJson() const
{
nlohmann::json nodes;
std::unordered_map<std::shared_ptr<const Node>, std::string> nodeKeys;
std::unordered_set<std::string> keys;
std::function<std::string(const std::string & key, std::shared_ptr<const Node> node)> dumpNode;
dumpNode = [&](std::string key, std::shared_ptr<const Node> node) -> std::string
{
auto k = nodeKeys.find(node);
if (k != nodeKeys.end())
return k->second;
if (!keys.insert(key).second) {
for (int n = 2; ; ++n) {
auto k = fmt("%s_%d", key, n);
if (keys.insert(k).second) {
key = k;
break;
}
}
}
nodeKeys.insert_or_assign(node, key);
auto n = nlohmann::json::object();
if (!node->inputs.empty()) {
auto inputs = nlohmann::json::object();
for (auto & i : node->inputs)
inputs[i.first] = dumpNode(i.first, i.second);
n["inputs"] = std::move(inputs);
}
if (auto lockedNode = std::dynamic_pointer_cast<const LockedNode>(node)) {
n["original"] = fetchers::attrsToJson(lockedNode->originalRef.toAttrs());
n["locked"] = fetchers::attrsToJson(lockedNode->lockedRef.toAttrs());
if (!lockedNode->isFlake) n["flake"] = false;
}
nodes[key] = std::move(n);
return key;
};
nlohmann::json json;
json["version"] = 6;
json["root"] = dumpNode("root", root);
json["nodes"] = std::move(nodes);
return json;
}
std::string LockFile::to_string() const
{
return toJson().dump(2);
}
LockFile LockFile::read(const Path & path)
{
if (!pathExists(path)) return LockFile();
return LockFile(nlohmann::json::parse(readFile(path)), path);
}
std::ostream & operator <<(std::ostream & stream, const LockFile & lockFile)
{
stream << lockFile.toJson().dump(2);
return stream;
}
void LockFile::write(const Path & path) const
{
createDirs(dirOf(path));
writeFile(path, fmt("%s\n", *this));
}
bool LockFile::isImmutable() const
{
std::unordered_set<std::shared_ptr<const Node>> nodes;
std::function<void(std::shared_ptr<const Node> node)> visit;
visit = [&](std::shared_ptr<const Node> node)
{
if (!nodes.insert(node).second) return;
for (auto & i : node->inputs) visit(i.second);
};
visit(root);
for (auto & i : nodes) {
if (i == root) continue;
auto lockedNode = std::dynamic_pointer_cast<const LockedNode>(i);
if (lockedNode && !lockedNode->lockedRef.input.isImmutable()) return false;
}
return true;
}
bool LockFile::operator ==(const LockFile & other) const
{
// FIXME: slow
return toJson() == other.toJson();
}
InputPath parseInputPath(std::string_view s)
{
InputPath path;
for (auto & elem : tokenizeString<std::vector<std::string>>(s, "/")) {
if (!std::regex_match(elem, flakeIdRegex))
throw UsageError("invalid flake input path element '%s'", elem);
path.push_back(elem);
}
return path;
}
static void flattenLockFile(
std::shared_ptr<const Node> node,
const InputPath & prefix,
std::unordered_set<std::shared_ptr<const Node>> & done,
std::map<InputPath, std::shared_ptr<const LockedNode>> & res)
{
if (!done.insert(node).second) return;
for (auto &[id, input] : node->inputs) {
auto inputPath(prefix);
inputPath.push_back(id);
if (auto lockedInput = std::dynamic_pointer_cast<const LockedNode>(input))
res.emplace(inputPath, lockedInput);
flattenLockFile(input, inputPath, done, res);
}
}
std::string diffLockFiles(const LockFile & oldLocks, const LockFile & newLocks)
{
std::unordered_set<std::shared_ptr<const Node>> done;
std::map<InputPath, std::shared_ptr<const LockedNode>> oldFlat, newFlat;
flattenLockFile(oldLocks.root, {}, done, oldFlat);
done.clear();
flattenLockFile(newLocks.root, {}, done, newFlat);
auto i = oldFlat.begin();
auto j = newFlat.begin();
std::string res;
while (i != oldFlat.end() || j != newFlat.end()) {
if (j != newFlat.end() && (i == oldFlat.end() || i->first > j->first)) {
res += fmt("* Added '%s': '%s'\n", printInputPath(j->first), j->second->lockedRef);
++j;
} else if (i != oldFlat.end() && (j == newFlat.end() || i->first < j->first)) {
res += fmt("* Removed '%s'\n", printInputPath(i->first));
++i;
} else {
if (!(i->second->lockedRef == j->second->lockedRef)) {
res += fmt("* Updated '%s': '%s' -> '%s'\n",
printInputPath(i->first),
i->second->lockedRef,
j->second->lockedRef);
}
++i;
++j;
}
}
return res;
}
std::string printInputPath(const InputPath & path)
{
return concatStringsSep("/", path);
}
}