forked from lix-project/lix
98 lines
3.1 KiB
C++
98 lines
3.1 KiB
C++
#include "content-address.hh"
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namespace nix {
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std::string FixedOutputHash::printMethodAlgo() const {
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return makeFileIngestionPrefix(method) + printHashType(hash.type);
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}
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std::string makeFileIngestionPrefix(const FileIngestionMethod m) {
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switch (m) {
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case FileIngestionMethod::Flat:
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return "";
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case FileIngestionMethod::Recursive:
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return "r:";
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default:
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throw Error("impossible, caught both cases");
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}
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}
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std::string makeFixedOutputCA(FileIngestionMethod method, const Hash & hash)
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{
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return "fixed:"
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+ makeFileIngestionPrefix(method)
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+ hash.to_string(Base32, true);
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}
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// FIXME Put this somewhere?
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template<class... Ts> struct overloaded : Ts... { using Ts::operator()...; };
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template<class... Ts> overloaded(Ts...) -> overloaded<Ts...>;
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std::string renderContentAddress(ContentAddress ca) {
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return std::visit(overloaded {
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[](TextHash th) {
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return "text:" + th.hash.to_string(Base32, true);
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},
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[](FixedOutputHash fsh) {
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return makeFixedOutputCA(fsh.method, fsh.hash);
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}
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}, ca);
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}
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ContentAddress parseContentAddress(std::string_view rawCa) {
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auto prefixSeparator = rawCa.find(':');
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if (prefixSeparator != string::npos) {
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auto prefix = string(rawCa, 0, prefixSeparator);
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if (prefix == "text") {
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auto hashTypeAndHash = rawCa.substr(prefixSeparator+1, string::npos);
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Hash hash = Hash(string(hashTypeAndHash));
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if (hash.type != htSHA256) {
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throw Error("parseContentAddress: the text hash should have type SHA256");
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}
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return TextHash { hash };
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} else if (prefix == "fixed") {
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// This has to be an inverse of makeFixedOutputCA
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auto methodAndHash = rawCa.substr(prefixSeparator+1, string::npos);
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if (methodAndHash.substr(0,2) == "r:") {
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std::string_view hashRaw = methodAndHash.substr(2,string::npos);
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return FixedOutputHash {
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.method = FileIngestionMethod::Recursive,
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.hash = Hash(string(hashRaw)),
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};
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} else {
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std::string_view hashRaw = methodAndHash;
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return FixedOutputHash {
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.method = FileIngestionMethod::Flat,
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.hash = Hash(string(hashRaw)),
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};
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}
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} else {
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throw Error("parseContentAddress: format not recognized; has to be text or fixed");
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}
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} else {
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throw Error("Not a content address because it lacks an appropriate prefix");
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}
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};
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std::optional<ContentAddress> parseContentAddressOpt(std::string_view rawCaOpt) {
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return rawCaOpt == "" ? std::optional<ContentAddress> {} : parseContentAddress(rawCaOpt);
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};
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std::string renderContentAddress(std::optional<ContentAddress> ca) {
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return ca ? renderContentAddress(*ca) : "";
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}
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Hash getContentAddressHash(const ContentAddress & ca)
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{
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return std::visit(overloaded {
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[](TextHash th) {
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return th.hash;
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},
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[](FixedOutputHash fsh) {
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return fsh.hash;
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}
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}, ca);
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}
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}
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