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nix/src/libstore-c/nix_api_store.cc
John Ericson 1c10ce6047 libstore-c: Add new derivation and store path functions
Add several new functions to the C API:

StorePath operations:
- nix_store_path_hash: Extract the hash part from a store path
- nix_store_create_from_parts: Construct a store path from hash and name

Derivation operations:
- nix_derivation_clone: Clone a derivation
- nix_derivation_to_json: Serialize a derivation to JSON

Store operations:
- nix_store_drv_from_store_path: Load a derivation from a store path

Test the new functions, and improve documentation of some existing
functions to better distinguish them, also.

Co-authored-by: Tristan Ross <tristan.ross@determinate.systems>
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
2025-11-25 13:18:10 -05:00

341 lines
9.2 KiB
C++

#include <cstring>
#include <span>
#include "nix_api_store.h"
#include "nix_api_store_internal.h"
#include "nix_api_util.h"
#include "nix_api_util_internal.h"
#include "nix/store/path.hh"
#include "nix/store/store-api.hh"
#include "nix/store/store-open.hh"
#include "nix/store/build-result.hh"
#include "nix/store/local-fs-store.hh"
#include "nix/util/base-nix-32.hh"
#include "nix/store/globals.hh"
extern "C" {
nix_err nix_libstore_init(nix_c_context * context)
{
if (context)
context->last_err_code = NIX_OK;
try {
nix::initLibStore();
}
NIXC_CATCH_ERRS
}
nix_err nix_libstore_init_no_load_config(nix_c_context * context)
{
if (context)
context->last_err_code = NIX_OK;
try {
nix::initLibStore(false);
}
NIXC_CATCH_ERRS
}
Store * nix_store_open(nix_c_context * context, const char * uri, const char *** params)
{
if (context)
context->last_err_code = NIX_OK;
try {
std::string uri_str = uri ? uri : "";
if (uri_str.empty())
return new Store{nix::openStore()};
if (!params)
return new Store{nix::openStore(uri_str)};
nix::Store::Config::Params params_map;
for (size_t i = 0; params[i] != nullptr; i++) {
params_map[params[i][0]] = params[i][1];
}
return new Store{nix::openStore(uri_str, params_map)};
}
NIXC_CATCH_ERRS_NULL
}
void nix_store_free(Store * store)
{
delete store;
}
nix_err nix_store_get_uri(nix_c_context * context, Store * store, nix_get_string_callback callback, void * user_data)
{
if (context)
context->last_err_code = NIX_OK;
try {
auto res = store->ptr->config.getReference().render(/*withParams=*/true);
return call_nix_get_string_callback(res, callback, user_data);
}
NIXC_CATCH_ERRS
}
nix_err
nix_store_get_storedir(nix_c_context * context, Store * store, nix_get_string_callback callback, void * user_data)
{
if (context)
context->last_err_code = NIX_OK;
try {
return call_nix_get_string_callback(store->ptr->storeDir, callback, user_data);
}
NIXC_CATCH_ERRS
}
nix_err
nix_store_get_version(nix_c_context * context, Store * store, nix_get_string_callback callback, void * user_data)
{
if (context)
context->last_err_code = NIX_OK;
try {
auto res = store->ptr->getVersion();
return call_nix_get_string_callback(res.value_or(""), callback, user_data);
}
NIXC_CATCH_ERRS
}
bool nix_store_is_valid_path(nix_c_context * context, Store * store, const StorePath * path)
{
if (context)
context->last_err_code = NIX_OK;
try {
return store->ptr->isValidPath(path->path);
}
NIXC_CATCH_ERRS_RES(false);
}
nix_err nix_store_real_path(
nix_c_context * context, Store * store, StorePath * path, nix_get_string_callback callback, void * user_data)
{
if (context)
context->last_err_code = NIX_OK;
try {
auto store2 = store->ptr.dynamic_pointer_cast<nix::LocalFSStore>();
auto res = store2 ? store2->toRealPath(path->path) : store->ptr->printStorePath(path->path);
return call_nix_get_string_callback(res, callback, user_data);
}
NIXC_CATCH_ERRS
}
StorePath * nix_store_parse_path(nix_c_context * context, Store * store, const char * path)
{
if (context)
context->last_err_code = NIX_OK;
try {
nix::StorePath s = store->ptr->parseStorePath(path);
return new StorePath{std::move(s)};
}
NIXC_CATCH_ERRS_NULL
}
nix_err nix_store_get_fs_closure(
nix_c_context * context,
Store * store,
const StorePath * store_path,
bool flip_direction,
bool include_outputs,
bool include_derivers,
void * userdata,
void (*callback)(nix_c_context * context, void * userdata, const StorePath * store_path))
{
if (context)
context->last_err_code = NIX_OK;
try {
const auto nixStore = store->ptr;
nix::StorePathSet set;
nixStore->computeFSClosure(store_path->path, set, flip_direction, include_outputs, include_derivers);
if (callback) {
for (const auto & path : set) {
const StorePath tmp{path};
callback(context, userdata, &tmp);
if (context && context->last_err_code != NIX_OK)
return context->last_err_code;
}
}
}
NIXC_CATCH_ERRS
}
nix_err nix_store_realise(
nix_c_context * context,
Store * store,
StorePath * path,
void * userdata,
void (*callback)(void * userdata, const char *, const StorePath *))
{
if (context)
context->last_err_code = NIX_OK;
try {
const std::vector<nix::DerivedPath> paths{nix::DerivedPath::Built{
.drvPath = nix::makeConstantStorePathRef(path->path), .outputs = nix::OutputsSpec::All{}}};
const auto nixStore = store->ptr;
auto results = nixStore->buildPathsWithResults(paths, nix::bmNormal, nixStore);
assert(results.size() == 1);
// Check if any builds failed
for (auto & result : results) {
if (auto * failureP = result.tryGetFailure())
failureP->rethrow();
}
if (callback) {
for (const auto & result : results) {
if (auto * success = result.tryGetSuccess()) {
for (const auto & [outputName, realisation] : success->builtOutputs) {
StorePath p{realisation.outPath};
callback(userdata, outputName.c_str(), &p);
}
}
}
}
}
NIXC_CATCH_ERRS
}
void nix_store_path_name(const StorePath * store_path, nix_get_string_callback callback, void * user_data)
{
std::string_view name = store_path->path.name();
callback(name.data(), name.size(), user_data);
}
void nix_store_path_free(StorePath * sp)
{
delete sp;
}
void nix_derivation_free(nix_derivation * drv)
{
delete drv;
}
StorePath * nix_store_path_clone(const StorePath * p)
{
try {
return new StorePath{p->path};
} catch (...) {
return nullptr;
}
}
} // extern "C"
template<size_t S>
static auto to_cpp_array(const uint8_t (&r)[S])
{
return reinterpret_cast<const std::array<std::byte, S> &>(r);
}
extern "C" {
nix_err
nix_store_path_hash(nix_c_context * context, const StorePath * store_path, nix_store_path_hash_part * hash_part_out)
{
try {
auto hashPart = store_path->path.hashPart();
// Decode from Nix32 (base32) encoding to raw bytes
auto decoded = nix::BaseNix32::decode(hashPart);
assert(decoded.size() == sizeof(hash_part_out->bytes));
std::memcpy(hash_part_out->bytes, decoded.data(), sizeof(hash_part_out->bytes));
return NIX_OK;
}
NIXC_CATCH_ERRS
}
StorePath * nix_store_create_from_parts(
nix_c_context * context, const nix_store_path_hash_part * hash, const char * name, size_t name_len)
{
if (context)
context->last_err_code = NIX_OK;
try {
// Encode the 20 raw bytes to Nix32 (base32) format
auto hashStr = nix::BaseNix32::encode(std::span<const std::byte>{to_cpp_array(hash->bytes)});
// Construct the store path basename: <hash>-<name>
std::string baseName;
baseName += hashStr;
baseName += "-";
baseName += std::string_view{name, name_len};
return new StorePath{nix::StorePath(std::move(baseName))};
}
NIXC_CATCH_ERRS_NULL
}
nix_derivation * nix_derivation_clone(const nix_derivation * d)
{
try {
return new nix_derivation{d->drv};
} catch (...) {
return nullptr;
}
}
nix_derivation * nix_derivation_from_json(nix_c_context * context, Store * store, const char * json)
{
if (context)
context->last_err_code = NIX_OK;
try {
return new nix_derivation{nix::Derivation::parseJsonAndValidate(*store->ptr, nlohmann::json::parse(json))};
}
NIXC_CATCH_ERRS_NULL
}
nix_err nix_derivation_to_json(
nix_c_context * context, const nix_derivation * drv, nix_get_string_callback callback, void * userdata)
{
if (context)
context->last_err_code = NIX_OK;
try {
auto result = static_cast<nlohmann::json>(drv->drv).dump();
if (callback) {
callback(result.data(), result.size(), userdata);
}
}
NIXC_CATCH_ERRS
}
StorePath * nix_add_derivation(nix_c_context * context, Store * store, nix_derivation * derivation)
{
if (context)
context->last_err_code = NIX_OK;
try {
auto ret = nix::writeDerivation(*store->ptr, derivation->drv, nix::NoRepair);
return new StorePath{ret};
}
NIXC_CATCH_ERRS_NULL
}
nix_err nix_store_copy_closure(nix_c_context * context, Store * srcStore, Store * dstStore, StorePath * path)
{
if (context)
context->last_err_code = NIX_OK;
try {
nix::RealisedPath::Set paths;
paths.insert(path->path);
nix::copyClosure(*srcStore->ptr, *dstStore->ptr, paths);
}
NIXC_CATCH_ERRS
}
nix_derivation * nix_store_drv_from_store_path(nix_c_context * context, Store * store, const StorePath * path)
{
if (context)
context->last_err_code = NIX_OK;
try {
return new nix_derivation{store->ptr->derivationFromPath(path->path)};
}
NIXC_CATCH_ERRS_NULL
}
} // extern "C"