From dfa547c6a81d6fb7ef3d3f69a98ebe969df42828 Mon Sep 17 00:00:00 2001 From: Robert Hensing Date: Thu, 17 Sep 2020 17:15:05 +0200 Subject: [PATCH] Add ContentAddressMethod and parse/render it --- src/libstore/content-address.cc | 62 ++++++++++++++++++++++++++------- src/libstore/content-address.hh | 19 ++++++++++ 2 files changed, 69 insertions(+), 12 deletions(-) diff --git a/src/libstore/content-address.cc b/src/libstore/content-address.cc index 0885c3d0e..bf56d3d77 100644 --- a/src/libstore/content-address.cc +++ b/src/libstore/content-address.cc @@ -37,48 +37,86 @@ std::string renderContentAddress(ContentAddress ca) { }, ca); } -ContentAddress parseContentAddress(std::string_view rawCa) { - auto rest = rawCa; +std::string renderContentAddressMethod(ContentAddressMethod cam) { + return std::visit(overloaded { + [](TextHashMethod &th) { + return std::string{"text:"} + printHashType(htSHA256); + }, + [](FixedOutputHashMethod &fshm) { + return "fixed:" + makeFileIngestionPrefix(fshm.fileIngestionMethod) + printHashType(fshm.hashType); + } + }, cam); +} + +/* + Parses content address strings up to the hash. + */ +static ContentAddressMethod parseContentAddressMethodPrefix(std::string_view & rest) { + std::string wholeInput(rest); std::string_view prefix; { auto optPrefix = splitPrefixTo(rest, ':'); if (!optPrefix) - throw UsageError("not a content address because it is not in the form ':': %s", rawCa); + throw UsageError("not a content address because it is not in the form ':': %s", wholeInput); prefix = *optPrefix; } auto parseHashType_ = [&](){ auto hashTypeRaw = splitPrefixTo(rest, ':'); if (!hashTypeRaw) - throw UsageError("content address hash must be in form ':', but found: %s", rawCa); + throw UsageError("content address hash must be in form ':', but found: %s", wholeInput); HashType hashType = parseHashType(*hashTypeRaw); return std::move(hashType); }; // Switch on prefix if (prefix == "text") { - // No parsing of the method, "text" only support flat. + // No parsing of the ingestion method, "text" only support flat. HashType hashType = parseHashType_(); if (hashType != htSHA256) throw Error("text content address hash should use %s, but instead uses %s", printHashType(htSHA256), printHashType(hashType)); - return TextHash { - .hash = Hash::parseNonSRIUnprefixed(rest, std::move(hashType)), - }; + return TextHashMethod {}; } else if (prefix == "fixed") { // Parse method auto method = FileIngestionMethod::Flat; if (splitPrefix(rest, "r:")) method = FileIngestionMethod::Recursive; HashType hashType = parseHashType_(); - return FixedOutputHash { - .method = method, - .hash = Hash::parseNonSRIUnprefixed(rest, std::move(hashType)), + return FixedOutputHashMethod { + .fileIngestionMethod = method, + .hashType = std::move(hashType), }; } else throw UsageError("content address prefix '%s' is unrecognized. Recogonized prefixes are 'text' or 'fixed'", prefix); -}; +} + +ContentAddress parseContentAddress(std::string_view rawCa) { + auto rest = rawCa; + + ContentAddressMethod caMethod = parseContentAddressMethodPrefix(rest); + + return std::visit( + overloaded { + [&](TextHashMethod thm) { + return ContentAddress(TextHash { + .hash = Hash::parseNonSRIUnprefixed(rest, htSHA256) + }); + }, + [&](FixedOutputHashMethod fohMethod) { + return ContentAddress(FixedOutputHash { + .method = fohMethod.fileIngestionMethod, + .hash = Hash::parseNonSRIUnprefixed(rest, std::move(fohMethod.hashType)), + }); + }, + }, caMethod); +} + +ContentAddressMethod parseContentAddressMethod(std::string_view caMethod) { + std::string_view asPrefix {std::string{caMethod} + ":"}; + return parseContentAddressMethodPrefix(asPrefix); +} std::optional parseContentAddressOpt(std::string_view rawCaOpt) { return rawCaOpt == "" ? std::optional {} : parseContentAddress(rawCaOpt); diff --git a/src/libstore/content-address.hh b/src/libstore/content-address.hh index 22a039242..f6a6f5140 100644 --- a/src/libstore/content-address.hh +++ b/src/libstore/content-address.hh @@ -55,4 +55,23 @@ std::optional parseContentAddressOpt(std::string_view rawCaOpt); Hash getContentAddressHash(const ContentAddress & ca); +/* + We only have one way to hash text with references, so this is single-value + type is only useful in std::variant. +*/ +struct TextHashMethod { }; +struct FixedOutputHashMethod { + FileIngestionMethod fileIngestionMethod; + HashType hashType; +}; + +typedef std::variant< + TextHashMethod, + FixedOutputHashMethod + > ContentAddressMethod; + +ContentAddressMethod parseContentAddressMethod(std::string_view rawCaMethod); + +std::string renderContentAddressMethod(ContentAddressMethod caMethod); + }