lix/src/libstore/fetchers/registry.cc

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#include "registry.hh"
#include "util.hh"
#include "fetchers.hh"
#include "globals.hh"
#include "download.hh"
#include <nlohmann/json.hpp>
namespace nix::fetchers {
std::shared_ptr<Registry> Registry::read(
const Path & path, RegistryType type)
{
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auto registry = std::make_shared<Registry>(type);
if (!pathExists(path))
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return std::make_shared<Registry>(type);
auto json = nlohmann::json::parse(readFile(path));
auto version = json.value("version", 0);
// FIXME: remove soon
if (version == 1) {
auto flakes = json["flakes"];
for (auto i = flakes.begin(); i != flakes.end(); ++i) {
auto url = i->value("url", i->value("uri", ""));
if (url.empty())
throw Error("flake registry '%s' lacks a 'url' attribute for entry '%s'",
path, i.key());
registry->entries.push_back(
{inputFromURL(i.key()), inputFromURL(url), {}});
}
}
else if (version == 2) {
for (auto & i : json["flakes"]) {
auto toAttrs = jsonToAttrs(i["to"]);
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Attrs extraAttrs;
auto j = toAttrs.find("dir");
if (j != toAttrs.end()) {
extraAttrs.insert(*j);
toAttrs.erase(j);
}
registry->entries.push_back(
{ inputFromAttrs(jsonToAttrs(i["from"]))
, inputFromAttrs(toAttrs)
, extraAttrs
});
}
}
else
throw Error("flake registry '%s' has unsupported version %d", path, version);
return registry;
}
void Registry::write(const Path & path)
{
nlohmann::json arr;
for (auto & elem : entries) {
nlohmann::json obj;
obj["from"] = attrsToJson(std::get<0>(elem)->toAttrs());
obj["to"] = attrsToJson(std::get<1>(elem)->toAttrs());
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if (!std::get<2>(elem).empty())
obj["to"].update(attrsToJson(std::get<2>(elem)));
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 std::shared_ptr<const Input> & from,
const std::shared_ptr<const Input> & to,
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const Attrs & extraAttrs)
{
entries.emplace_back(from, to, extraAttrs);
}
void Registry::remove(const std::shared_ptr<const Input> & input)
{
// FIXME: use C++20 std::erase.
for (auto i = entries.begin(); i != entries.end(); )
if (*std::get<0>(*i) == *input)
i = entries.erase(i);
else
++i;
}
Path getUserRegistryPath()
{
return getHome() + "/.config/nix/registry.json";
}
std::shared_ptr<Registry> getUserRegistry()
{
return Registry::read(getUserRegistryPath(), Registry::User);
}
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static std::shared_ptr<Registry> flagRegistry =
std::make_shared<Registry>(Registry::Flag);
std::shared_ptr<Registry> getFlagRegistry()
{
return flagRegistry;
}
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void overrideRegistry(
const std::shared_ptr<const Input> & from,
const std::shared_ptr<const Input> & to,
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const Attrs & extraAttrs)
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{
flagRegistry->add(from, to, extraAttrs);
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}
static std::shared_ptr<Registry> getGlobalRegistry(ref<Store> store)
{
static auto reg = [&]() {
auto path = settings.flakeRegistry;
if (!hasPrefix(path, "/")) {
CachedDownloadRequest request(path);
request.name = "flake-registry.json";
request.gcRoot = true;
path = getDownloader()->downloadCached(store, request).path;
}
return Registry::read(path, Registry::Global);
}();
return reg;
}
Registries getRegistries(ref<Store> store)
{
Registries registries;
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registries.push_back(getFlagRegistry());
registries.push_back(getUserRegistry());
registries.push_back(getGlobalRegistry(store));
return registries;
}
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std::pair<std::shared_ptr<const Input>, Attrs> lookupInRegistries(
ref<Store> store,
std::shared_ptr<const Input> input)
{
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Attrs extraAttrs;
int n = 0;
restart:
n++;
if (n > 100) throw Error("cycle detected in flake registr for '%s'", input);
for (auto & registry : getRegistries(store)) {
// FIXME: O(n)
for (auto & entry : registry->entries) {
auto from = std::get<0>(entry);
if (from->contains(*input)) {
input = std::get<1>(entry)->applyOverrides(
!from->getRef() && input->getRef() ? input->getRef() : std::optional<std::string>(),
!from->getRev() && input->getRev() ? input->getRev() : std::optional<Hash>());
extraAttrs = std::get<2>(entry);
goto restart;
}
}
}
if (!input->isDirect())
throw Error("cannot find flake '%s' in the flake registries", input->to_string());
return {input, extraAttrs};
}
}