nix-super/src/libexpr/flake/lockfile.cc
2020-10-26 17:01:20 +01:00

340 lines
9.9 KiB
C++

#include "lockfile.hh"
#include "store-api.hh"
#include "url-parts.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 = fetchers::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 : fetchers::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'",
fetchers::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);
}
}