lix/src/libfetchers/registry.cc
2021-06-30 22:16:40 +03:00

221 lines
5.8 KiB
C++

#include "registry.hh"
#include "fetchers.hh"
#include "util.hh"
#include "globals.hh"
#include "store-api.hh"
#include "local-fs-store.hh"
#include <nlohmann/json.hpp>
namespace nix::fetchers {
std::shared_ptr<Registry> Registry::read(
const Path & path, RegistryType type)
{
auto registry = std::make_shared<Registry>(type);
if (!pathExists(path))
return std::make_shared<Registry>(type);
try {
auto json = nlohmann::json::parse(readFile(path));
auto version = json.value("version", 0);
if (version == 2) {
for (auto & i : json["flakes"]) {
auto toAttrs = jsonToAttrs(i["to"]);
Attrs extraAttrs;
auto j = toAttrs.find("dir");
if (j != toAttrs.end()) {
extraAttrs.insert(*j);
toAttrs.erase(j);
}
auto exact = i.find("exact");
registry->entries.push_back(
Entry {
.from = Input::fromAttrs(jsonToAttrs(i["from"])),
.to = Input::fromAttrs(std::move(toAttrs)),
.extraAttrs = extraAttrs,
.exact = exact != i.end() && exact.value()
});
}
}
else
throw Error("flake registry '%s' has unsupported version %d", path, version);
} catch (nlohmann::json::exception & e) {
warn("cannot parse flake registry '%s': %s", path, e.what());
} catch (Error & e) {
warn("cannot read flake registry '%s': %s", path, e.what());
}
return registry;
}
void Registry::write(const Path & path)
{
nlohmann::json arr;
for (auto & entry : entries) {
nlohmann::json obj;
obj["from"] = attrsToJSON(entry.from.toAttrs());
obj["to"] = attrsToJSON(entry.to.toAttrs());
if (!entry.extraAttrs.empty())
obj["to"].update(attrsToJSON(entry.extraAttrs));
if (entry.exact)
obj["exact"] = true;
arr.emplace_back(std::move(obj));
}
nlohmann::json json;
json["version"] = 2;
json["flakes"] = std::move(arr);
createDirs(dirOf(path));
writeFile(path, json.dump(2));
}
void Registry::add(
const Input & from,
const Input & to,
const Attrs & extraAttrs)
{
entries.emplace_back(
Entry {
.from = from,
.to = to,
.extraAttrs = extraAttrs
});
}
void Registry::remove(const Input & input)
{
// FIXME: use C++20 std::erase.
for (auto i = entries.begin(); i != entries.end(); )
if (i->from == input)
i = entries.erase(i);
else
++i;
}
static Path getSystemRegistryPath()
{
return settings.nixConfDir + "/registry.json";
}
static std::shared_ptr<Registry> getSystemRegistry()
{
static auto systemRegistry =
Registry::read(getSystemRegistryPath(), Registry::System);
return systemRegistry;
}
Path getUserRegistryPath()
{
return getConfigDir() + "/nix/registry.json";
}
std::shared_ptr<Registry> getUserRegistry()
{
static auto userRegistry =
Registry::read(getUserRegistryPath(), Registry::User);
return userRegistry;
}
std::shared_ptr<Registry> getCustomRegistry(Path p)
{
static auto customRegistry =
Registry::read(p, Registry::Custom);
return customRegistry;
}
static std::shared_ptr<Registry> flagRegistry =
std::make_shared<Registry>(Registry::Flag);
std::shared_ptr<Registry> getFlagRegistry()
{
return flagRegistry;
}
void overrideRegistry(
const Input & from,
const Input & to,
const Attrs & extraAttrs)
{
flagRegistry->add(from, to, extraAttrs);
}
static std::shared_ptr<Registry> getGlobalRegistry(ref<Store> store)
{
static auto reg = [&]() {
auto path = settings.flakeRegistry.get();
if (!hasPrefix(path, "/")) {
auto storePath = downloadFile(store, path, "flake-registry.json", false).storePath;
if (auto store2 = store.dynamic_pointer_cast<LocalFSStore>())
store2->addPermRoot(storePath, getCacheDir() + "/nix/flake-registry.json");
path = store->toRealPath(storePath);
}
return Registry::read(path, Registry::Global);
}();
return reg;
}
Registries getRegistries(ref<Store> store)
{
Registries registries;
registries.push_back(getFlagRegistry());
registries.push_back(getUserRegistry());
registries.push_back(getSystemRegistry());
registries.push_back(getGlobalRegistry(store));
return registries;
}
std::pair<Input, Attrs> lookupInRegistries(
ref<Store> store,
const Input & _input)
{
Attrs extraAttrs;
int n = 0;
Input input(_input);
restart:
n++;
if (n > 100) throw Error("cycle detected in flake registry for '%s'", input.to_string());
for (auto & registry : getRegistries(store)) {
// FIXME: O(n)
for (auto & entry : registry->entries) {
if (entry.exact) {
if (entry.from == input) {
input = entry.to;
extraAttrs = entry.extraAttrs;
goto restart;
}
} else {
if (entry.from.contains(input)) {
input = entry.to.applyOverrides(
!entry.from.getRef() && input.getRef() ? input.getRef() : std::optional<std::string>(),
!entry.from.getRev() && input.getRev() ? input.getRev() : std::optional<Hash>());
extraAttrs = entry.extraAttrs;
goto restart;
}
}
}
}
if (!input.isDirect())
throw Error("cannot find flake '%s' in the flake registries", input.to_string());
debug("looked up '%s' -> '%s'", _input.to_string(), input.to_string());
return {input, extraAttrs};
}
}