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nix/src/libflake/flakeref.cc
Eelco Dolstra 5a2ee1b952 Move libflake/flake/* to libflake
(cherry picked from commit bc67e47298)
2025-04-23 19:06:03 +00:00

308 lines
10 KiB
C++

#include "nix/flake/flakeref.hh"
#include "nix/store/store-api.hh"
#include "nix/util/url.hh"
#include "nix/util/url-parts.hh"
#include "nix/fetchers/fetchers.hh"
namespace nix {
#if 0
// 'dir' path elements cannot start with a '.'. We also reject
// potentially dangerous characters like ';'.
const static std::string subDirElemRegex = "(?:[a-zA-Z0-9_-]+[a-zA-Z0-9._-]*)";
const static std::string subDirRegex = subDirElemRegex + "(?:/" + subDirElemRegex + ")*";
#endif
std::string FlakeRef::to_string() const
{
std::map<std::string, std::string> extraQuery;
if (subdir != "")
extraQuery.insert_or_assign("dir", subdir);
return input.toURLString(extraQuery);
}
fetchers::Attrs FlakeRef::toAttrs() const
{
auto attrs = input.toAttrs();
if (subdir != "")
attrs.emplace("dir", subdir);
return attrs;
}
std::ostream & operator << (std::ostream & str, const FlakeRef & flakeRef)
{
str << flakeRef.to_string();
return str;
}
FlakeRef FlakeRef::resolve(
ref<Store> store,
const fetchers::RegistryFilter & filter) const
{
auto [input2, extraAttrs] = lookupInRegistries(store, input, filter);
return FlakeRef(std::move(input2), fetchers::maybeGetStrAttr(extraAttrs, "dir").value_or(subdir));
}
FlakeRef parseFlakeRef(
const fetchers::Settings & fetchSettings,
const std::string & url,
const std::optional<Path> & baseDir,
bool allowMissing,
bool isFlake,
bool preserveRelativePaths)
{
auto [flakeRef, fragment] = parseFlakeRefWithFragment(fetchSettings, url, baseDir, allowMissing, isFlake, preserveRelativePaths);
if (fragment != "")
throw Error("unexpected fragment '%s' in flake reference '%s'", fragment, url);
return flakeRef;
}
std::optional<FlakeRef> maybeParseFlakeRef(
const fetchers::Settings & fetchSettings,
const std::string & url,
const std::optional<Path> & baseDir)
{
try {
return parseFlakeRef(fetchSettings, url, baseDir);
} catch (Error &) {
return {};
}
}
static std::pair<FlakeRef, std::string> fromParsedURL(
const fetchers::Settings & fetchSettings,
ParsedURL && parsedURL,
bool isFlake)
{
auto dir = getOr(parsedURL.query, "dir", "");
parsedURL.query.erase("dir");
std::string fragment;
std::swap(fragment, parsedURL.fragment);
return {FlakeRef(fetchers::Input::fromURL(fetchSettings, parsedURL, isFlake), dir), fragment};
}
std::pair<FlakeRef, std::string> parsePathFlakeRefWithFragment(
const fetchers::Settings & fetchSettings,
const std::string & url,
const std::optional<Path> & baseDir,
bool allowMissing,
bool isFlake,
bool preserveRelativePaths)
{
static std::regex pathFlakeRegex(
R"(([^?#]*)(\?([^#]*))?(#(.*))?)",
std::regex::ECMAScript);
std::smatch match;
auto succeeds = std::regex_match(url, match, pathFlakeRegex);
assert(succeeds);
auto path = match[1].str();
auto query = decodeQuery(match[3]);
auto fragment = percentDecode(match[5].str());
if (baseDir) {
/* Check if 'url' is a path (either absolute or relative
to 'baseDir'). If so, search upward to the root of the
repo (i.e. the directory containing .git). */
path = absPath(path, baseDir, true);
if (isFlake) {
if (!S_ISDIR(lstat(path).st_mode)) {
if (baseNameOf(path) == "flake.nix") {
// Be gentle with people who accidentally write `/foo/bar/flake.nix` instead of `/foo/bar`
warn(
"Path '%s' should point at the directory containing the 'flake.nix' file, not the file itself. "
"Pretending that you meant '%s'"
, path, dirOf(path));
path = dirOf(path);
} else {
throw BadURL("path '%s' is not a flake (because it's not a directory)", path);
}
}
if (!allowMissing && !pathExists(path + "/flake.nix")){
notice("path '%s' does not contain a 'flake.nix', searching up",path);
// Save device to detect filesystem boundary
dev_t device = lstat(path).st_dev;
bool found = false;
while (path != "/") {
if (pathExists(path + "/flake.nix")) {
found = true;
break;
} else if (pathExists(path + "/.git"))
throw Error("path '%s' is not part of a flake (neither it nor its parent directories contain a 'flake.nix' file)", path);
else {
if (lstat(path).st_dev != device)
throw Error("unable to find a flake before encountering filesystem boundary at '%s'", path);
}
path = dirOf(path);
}
if (!found)
throw BadURL("could not find a flake.nix file");
}
if (!allowMissing && !pathExists(path + "/flake.nix"))
throw BadURL("path '%s' is not a flake (because it doesn't contain a 'flake.nix' file)", path);
auto flakeRoot = path;
std::string subdir;
while (flakeRoot != "/") {
if (pathExists(flakeRoot + "/.git")) {
auto parsedURL = ParsedURL{
.scheme = "git+file",
.authority = "",
.path = flakeRoot,
.query = query,
.fragment = fragment,
};
if (subdir != "") {
if (parsedURL.query.count("dir"))
throw Error("flake URL '%s' has an inconsistent 'dir' parameter", url);
parsedURL.query.insert_or_assign("dir", subdir);
}
if (pathExists(flakeRoot + "/.git/shallow"))
parsedURL.query.insert_or_assign("shallow", "1");
return fromParsedURL(fetchSettings, std::move(parsedURL), isFlake);
}
subdir = std::string(baseNameOf(flakeRoot)) + (subdir.empty() ? "" : "/" + subdir);
flakeRoot = dirOf(flakeRoot);
}
}
} else {
if (!preserveRelativePaths && !isAbsolute(path))
throw BadURL("flake reference '%s' is not an absolute path", url);
}
return fromParsedURL(fetchSettings, {
.scheme = "path",
.authority = "",
.path = path,
.query = query,
.fragment = fragment
}, isFlake);
}
/**
* Check if `url` is a flake ID. This is an abbreviated syntax for
* `flake:<flake-id>?ref=<ref>&rev=<rev>`.
*/
static std::optional<std::pair<FlakeRef, std::string>> parseFlakeIdRef(
const fetchers::Settings & fetchSettings,
const std::string & url,
bool isFlake)
{
std::smatch match;
static std::regex flakeRegex(
"((" + flakeIdRegexS + ")(?:/(?:" + refAndOrRevRegex + "))?)"
+ "(?:#(" + fragmentRegex + "))?",
std::regex::ECMAScript);
if (std::regex_match(url, match, flakeRegex)) {
auto parsedURL = ParsedURL{
.scheme = "flake",
.authority = "",
.path = match[1],
};
return std::make_pair(
FlakeRef(fetchers::Input::fromURL(fetchSettings, parsedURL, isFlake), ""),
percentDecode(match.str(6)));
}
return {};
}
std::optional<std::pair<FlakeRef, std::string>> parseURLFlakeRef(
const fetchers::Settings & fetchSettings,
const std::string & url,
const std::optional<Path> & baseDir,
bool isFlake)
{
try {
auto parsed = parseURL(url);
if (baseDir
&& (parsed.scheme == "path" || parsed.scheme == "git+file")
&& !isAbsolute(parsed.path))
parsed.path = absPath(parsed.path, *baseDir);
return fromParsedURL(fetchSettings, std::move(parsed), isFlake);
} catch (BadURL &) {
return std::nullopt;
}
}
std::pair<FlakeRef, std::string> parseFlakeRefWithFragment(
const fetchers::Settings & fetchSettings,
const std::string & url,
const std::optional<Path> & baseDir,
bool allowMissing,
bool isFlake,
bool preserveRelativePaths)
{
using namespace fetchers;
if (auto res = parseFlakeIdRef(fetchSettings, url, isFlake)) {
return *res;
} else if (auto res = parseURLFlakeRef(fetchSettings, url, baseDir, isFlake)) {
return *res;
} else {
return parsePathFlakeRefWithFragment(fetchSettings, url, baseDir, allowMissing, isFlake, preserveRelativePaths);
}
}
std::optional<std::pair<FlakeRef, std::string>> maybeParseFlakeRefWithFragment(
const fetchers::Settings & fetchSettings,
const std::string & url, const std::optional<Path> & baseDir)
{
try {
return parseFlakeRefWithFragment(fetchSettings, url, baseDir);
} catch (Error & e) {
return {};
}
}
FlakeRef FlakeRef::fromAttrs(
const fetchers::Settings & fetchSettings,
const fetchers::Attrs & attrs)
{
auto attrs2(attrs);
attrs2.erase("dir");
return FlakeRef(
fetchers::Input::fromAttrs(fetchSettings, std::move(attrs2)),
fetchers::maybeGetStrAttr(attrs, "dir").value_or(""));
}
std::pair<ref<SourceAccessor>, FlakeRef> FlakeRef::lazyFetch(ref<Store> store) const
{
auto [accessor, lockedInput] = input.getAccessor(store);
return {accessor, FlakeRef(std::move(lockedInput), subdir)};
}
std::tuple<FlakeRef, std::string, ExtendedOutputsSpec> parseFlakeRefWithFragmentAndExtendedOutputsSpec(
const fetchers::Settings & fetchSettings,
const std::string & url,
const std::optional<Path> & baseDir,
bool allowMissing,
bool isFlake)
{
auto [prefix, extendedOutputsSpec] = ExtendedOutputsSpec::parse(url);
auto [flakeRef, fragment] = parseFlakeRefWithFragment(
fetchSettings,
std::string { prefix }, baseDir, allowMissing, isFlake);
return {std::move(flakeRef), fragment, std::move(extendedOutputsSpec)};
}
std::regex flakeIdRegex(flakeIdRegexS, std::regex::ECMAScript);
}