diff options
Diffstat (limited to 'src/libexpr/flake/lockfile.cc')
| -rw-r--r-- | src/libexpr/flake/lockfile.cc | 338 |
1 files changed, 338 insertions, 0 deletions
diff --git a/src/libexpr/flake/lockfile.cc b/src/libexpr/flake/lockfile.cc new file mode 100644 index 000000000..a74846944 --- /dev/null +++ b/src/libexpr/flake/lockfile.cc @@ -0,0 +1,338 @@ +#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> LockFile::findInput(const InputPath & path) +{ + auto pos = root; + + if (!pos) return {}; + + for (auto & elem : path) { + if (auto i = get(pos->inputs, elem)) { + if (auto node = std::get_if<0>(&*i)) + pos = *node; + else if (auto follows = std::get_if<1>(&*i)) { + pos = findInput(*follows); + if (!pos) return {}; + } + } else + return {}; + } + + return pos; +} + +LockFile::LockFile(const nlohmann::json & json, const Path & path) +{ + auto version = json.value("version", 0); + if (version < 5 || version > 7) + 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()) { + if (i.value().is_array()) { + InputPath path; + for (auto & j : i.value()) + path.push_back(j); + node.inputs.insert_or_assign(i.key(), path); + } else { + 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); + } + if (auto child = std::dynamic_pointer_cast<LockedNode>(k->second)) + node.inputs.insert_or_assign(i.key(), child); + else + // FIXME: replace by follows node + throw Error("lock file contains cycle to root node"); + } + } + }; + + std::string rootKey = json["root"]; + nodeMap.insert_or_assign(rootKey, root); + getInputs(*root, json["nodes"][rootKey]); + + // FIXME: check that there are no cycles in version >= 7. Cycles + // between inputs are only possible using 'follows' indirections. + // Once we drop support for version <= 6, we can simplify the code + // a bit since we don't need to worry about cycles. +} + +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) { + if (auto child = std::get_if<0>(&i.second)) { + inputs[i.first] = dumpNode(i.first, *child); + } else if (auto follows = std::get_if<1>(&i.second)) { + auto arr = nlohmann::json::array(); + for (auto & x : *follows) + arr.push_back(x); + inputs[i.first] = std::move(arr); + } + } + 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"] = 7; + 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) + if (auto child = std::get_if<0>(&i.second)) + visit(*child); + }; + + 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; +} + +std::map<InputPath, Node::Edge> LockFile::getAllInputs() const +{ + std::unordered_set<std::shared_ptr<Node>> done; + std::map<InputPath, Node::Edge> res; + + std::function<void(const InputPath & prefix, std::shared_ptr<Node> node)> recurse; + + recurse = [&](const InputPath & prefix, std::shared_ptr<Node> node) + { + if (!done.insert(node).second) return; + + for (auto &[id, input] : node->inputs) { + auto inputPath(prefix); + inputPath.push_back(id); + res.emplace(inputPath, input); + if (auto child = std::get_if<0>(&input)) + recurse(inputPath, *child); + } + }; + + recurse({}, root); + + return res; +} + +std::ostream & operator <<(std::ostream & stream, const Node::Edge & edge) +{ + if (auto node = std::get_if<0>(&edge)) + stream << "'" << (*node)->lockedRef << "'"; + else if (auto follows = std::get_if<1>(&edge)) + stream << fmt("follows '%s'", printInputPath(*follows)); + return stream; +} + +static bool equals(const Node::Edge & e1, const Node::Edge & e2) +{ + if (auto n1 = std::get_if<0>(&e1)) + if (auto n2 = std::get_if<0>(&e2)) + return (*n1)->lockedRef == (*n2)->lockedRef; + if (auto f1 = std::get_if<1>(&e1)) + if (auto f2 = std::get_if<1>(&e2)) + return *f1 == *f2; + return false; +} + +std::string LockFile::diff(const LockFile & oldLocks, const LockFile & newLocks) +{ + auto oldFlat = oldLocks.getAllInputs(); + auto newFlat = newLocks.getAllInputs(); + + 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); + ++j; + } else if (i != oldFlat.end() && (j == newFlat.end() || i->first < j->first)) { + res += fmt("* Removed '%s'\n", printInputPath(i->first)); + ++i; + } else { + if (!equals(i->second, j->second)) { + res += fmt("* Updated '%s': %s -> %s\n", + printInputPath(i->first), + i->second, + j->second); + } + ++i; + ++j; + } + } + + return res; +} + +void LockFile::check() +{ + auto inputs = getAllInputs(); + + for (auto & [inputPath, input] : inputs) { + if (auto follows = std::get_if<1>(&input)) { + if (!follows->empty() && !get(inputs, *follows)) + throw Error("input '%s' follows a non-existent input '%s'", + printInputPath(inputPath), + printInputPath(*follows)); + } + } +} + +void check(); + +std::string printInputPath(const InputPath & path) +{ + return concatStringsSep("/", path); +} + +} |