lix/src/libexpr/primops/flakeref.cc

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2019-02-12 17:23:11 +00:00
#include "flakeref.hh"
#include <regex>
namespace nix {
// A Git ref (i.e. branch or tag name).
const static std::string refRegex = "[a-zA-Z][a-zA-Z0-9_.-]*"; // FIXME: check
// A Git revision (a SHA-1 commit hash).
const static std::string revRegexS = "[0-9a-fA-F]{40}";
std::regex revRegex(revRegexS, std::regex::ECMAScript);
// A Git ref or revision.
const static std::string revOrRefRegex = "(?:(" + revRegexS + ")|(" + refRegex + "))";
// A rev ("e72daba8250068216d79d2aeef40d4d95aff6666"), or a ref
// optionally followed by a rev (e.g. "master" or
// "master/e72daba8250068216d79d2aeef40d4d95aff6666").
const static std::string refAndOrRevRegex = "(?:(" + revRegexS + ")|(?:(" + refRegex + ")(?:/(" + revRegexS + "))?))";
const static std::string flakeId = "[a-zA-Z][a-zA-Z0-9_-]*";
// GitHub references.
const static std::string ownerRegex = "[a-zA-Z][a-zA-Z0-9_-]*";
const static std::string repoRegex = "[a-zA-Z][a-zA-Z0-9_-]*";
// URI stuff.
const static std::string schemeRegex = "(?:http|https|ssh|git|file)";
const static std::string authorityRegex = "[a-zA-Z0-9._~-]*";
const static std::string segmentRegex = "[a-zA-Z0-9._~-]+";
const static std::string pathRegex = "/?" + segmentRegex + "(?:/" + segmentRegex + ")*";
const static std::string paramRegex = "[a-z]+=[a-zA-Z0-9._-]*";
FlakeRef::FlakeRef(const std::string & uri)
{
// FIXME: could combine this into one regex.
static std::regex flakeRegex(
"(?:flake:)?(" + flakeId + ")(?:/(?:" + refAndOrRevRegex + "))?",
std::regex::ECMAScript);
static std::regex githubRegex(
"github:(" + ownerRegex + ")/(" + repoRegex + ")(?:/" + revOrRefRegex + ")?",
std::regex::ECMAScript);
static std::regex uriRegex(
"((" + schemeRegex + "):" +
"(?://(" + authorityRegex + "))?" +
"(" + pathRegex + "))" +
"(?:[?](" + paramRegex + "(?:&" + paramRegex + ")*))?",
std::regex::ECMAScript);
static std::regex refRegex2(refRegex, std::regex::ECMAScript);
std::cmatch match;
if (std::regex_match(uri.c_str(), match, flakeRegex)) {
IsFlakeId d;
d.id = match[1];
if (match[2].matched)
d.rev = Hash(match[2], htSHA1);
else if (match[3].matched) {
d.ref = match[3];
if (match[4].matched)
d.rev = Hash(match[4], htSHA1);
}
data = d;
}
else if (std::regex_match(uri.c_str(), match, githubRegex)) {
IsGitHub d;
d.owner = match[1];
d.repo = match[2];
if (match[3].matched)
d.rev = Hash(match[3], htSHA1);
else if (match[4].matched) {
d.ref = match[4];
}
data = d;
}
else if (std::regex_match(uri.c_str(), match, uriRegex) && hasSuffix(match[4], ".git")) {
IsGit d;
d.uri = match[1];
for (auto & param : tokenizeString<Strings>(match[5], "&")) {
auto n = param.find('=');
assert(n != param.npos);
std::string name(param, 0, n);
std::string value(param, n + 1);
if (name == "rev") {
if (!std::regex_match(value, revRegex))
throw Error("invalid Git revision '%s'", value);
d.rev = Hash(value, htSHA1);
} else if (name == "ref") {
if (!std::regex_match(value, refRegex2))
throw Error("invalid Git ref '%s'", value);
d.ref = value;
} else
// FIXME: should probably pass through unknown parameters
throw Error("invalid Git flake reference parameter '%s', in '%s'", name, uri);
}
if (d.rev && !d.ref)
throw Error("flake URI '%s' lacks a Git ref", uri);
data = d;
}
else
throw Error("'%s' is not a valid flake reference", uri);
}
std::string FlakeRef::to_string() const
{
if (auto refData = std::get_if<FlakeRef::IsFlakeId>(&data)) {
return
"flake:" + refData->id +
(refData->ref ? "/" + *refData->ref : "") +
(refData->rev ? "/" + refData->rev->to_string(Base16, false) : "");
}
else if (auto refData = std::get_if<FlakeRef::IsGitHub>(&data)) {
assert(!refData->ref || !refData->rev);
return
"github:" + refData->owner + "/" + refData->repo +
(refData->ref ? "/" + *refData->ref : "") +
(refData->rev ? "/" + refData->rev->to_string(Base16, false) : "");
}
else if (auto refData = std::get_if<FlakeRef::IsGit>(&data)) {
assert(refData->ref || !refData->rev);
return
refData->uri +
(refData->ref ? "?ref=" + *refData->ref : "") +
(refData->rev ? "&rev=" + refData->rev->to_string(Base16, false) : "");
}
else abort();
}
}