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WIP: Make Hash always store a valid hash type

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This commit is contained in:
John Ericson 2020-06-19 18:41:33 +00:00
parent 984e521392
commit 507aa48739
29 changed files with 126 additions and 124 deletions
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68
src/libutil/hash.cc
View file

@ -16,16 +16,19 @@
namespace nix {
static size_t regularHashSize(HashType type) {
switch (type) {
case htMD5: return md5HashSize;
case htSHA1: return sha1HashSize;
case htSHA256: return sha256HashSize;
case htSHA512: return sha512HashSize;
}
abort();
}
void Hash::init()
{
if (!type) abort();
switch (*type) {
case htMD5: hashSize = md5HashSize; break;
case htSHA1: hashSize = sha1HashSize; break;
case htSHA256: hashSize = sha256HashSize; break;
case htSHA512: hashSize = sha512HashSize; break;
}
hashSize = regularHashSize(type);
assert(hashSize <= maxHashSize);
memset(hash, 0, maxHashSize);
}
@ -105,18 +108,11 @@ string printHash16or32(const Hash & hash)
}
HashType assertInitHashType(const Hash & h) {
if (h.type)
return *h.type;
else
abort();
}
std::string Hash::to_string(Base base, bool includeType) const
{
std::string s;
if (base == SRI || includeType) {
s += printHashType(assertInitHashType(*this));
s += printHashType(type);
s += base == SRI ? '-' : ':';
}
switch (base) {
@ -137,31 +133,39 @@ std::string Hash::to_string(Base base, bool includeType) const
Hash::Hash(std::string_view s, HashType type) : Hash(s, std::optional { type }) { }
Hash::Hash(std::string_view s) : Hash(s, std::optional<HashType>{}) { }
Hash::Hash(std::string_view s, std::optional<HashType> type)
: type(type)
Hash::Hash(std::string_view s, std::optional<HashType> optType)
{
size_t pos = 0;
bool isSRI = false;
// Find the : or - separater, and set `isSRI` to the correct value
auto sep = s.find(':');
if (sep == string::npos) {
if (sep == std::string_view::npos) {
sep = s.find('-');
if (sep != string::npos) {
if (sep != std::string_view::npos)
isSRI = true;
} else if (! type)
throw BadHash("hash '%s' does not include a type", s);
}
if (sep != string::npos) {
string hts = string(s, 0, sep);
this->type = parseHashType(hts);
if (!this->type)
// Parse the has type before the separater, if there was one.
std::optional<HashType> optParsedType;
if (sep != std::string_view::npos) {
auto hts = s.substr(0, sep);
auto optParsedType = parseHashTypeOpt(hts);
if (!optParsedType)
throw BadHash("unknown hash type '%s'", hts);
if (type && type != this->type)
throw BadHash("hash '%s' should have type '%s'", s, printHashType(*type));
pos = sep + 1;
}
// Either the string or user must provide the type, if they both do they
// must agree.
if (!optParsedType && !optType) {
throw BadHash("hash '%s' does not include a type, nor is the type otherwise known from context.", s);
} else {
this->type = optParsedType ? *optParsedType : *optType;
if (optParsedType && optType && *optParsedType != *optType)
throw BadHash("hash '%s' should have type '%s'", s, printHashType(*optType));
}
init();
size_t size = s.size() - pos;
@ -214,7 +218,7 @@ Hash::Hash(std::string_view s, std::optional<HashType> type)
}
else
throw BadHash("hash '%s' has wrong length for hash type '%s'", s, printHashType(*type));
throw BadHash("hash '%s' has wrong length for hash type '%s'", s, printHashType(type));
}
Hash newHashAllowEmpty(std::string hashStr, std::optional<HashType> ht)
@ -267,7 +271,7 @@ static void finish(HashType ht, Ctx & ctx, unsigned char * hash)
}
Hash hashString(HashType ht, const string & s)
Hash hashString(HashType ht, std::string_view s)
{
Ctx ctx;
Hash hash(ht);
@ -334,7 +338,7 @@ HashResult hashPath(
Hash compressHash(const Hash & hash, unsigned int newSize)
{
Hash h;
Hash h(hash.type);
h.hashSize = newSize;
for (unsigned int i = 0; i < hash.hashSize; ++i)
h.hash[i % newSize] ^= hash.hash[i];
@ -342,7 +346,7 @@ Hash compressHash(const Hash & hash, unsigned int newSize)
}
std::optional<HashType> parseHashTypeOpt(const string & s)
std::optional<HashType> parseHashTypeOpt(std::string_view s)
{
if (s == "md5") return htMD5;
else if (s == "sha1") return htSHA1;
@ -351,7 +355,7 @@ std::optional<HashType> parseHashTypeOpt(const string & s)
else return std::optional<HashType> {};
}
HashType parseHashType(const string & s)
HashType parseHashType(std::string_view s)
{
auto opt_h = parseHashTypeOpt(s);
if (opt_h)

17
src/libutil/hash.hh
View file

@ -25,14 +25,11 @@ enum Base : int { Base64, Base32, Base16, SRI };
struct Hash
{
static const unsigned int maxHashSize = 64;
unsigned int hashSize = 0;
unsigned char hash[maxHashSize] = {};
constexpr static size_t maxHashSize = 64;
size_t hashSize = 0;
uint8_t hash[maxHashSize] = {};
std::optional<HashType> type = {};
/* Create an unset hash object. */
Hash() { };
HashType type;
/* Create a zero-filled hash object. */
Hash(HashType type) : type(type) { init(); };
@ -105,7 +102,7 @@ Hash newHashAllowEmpty(std::string hashStr, std::optional<HashType> ht);
string printHash16or32(const Hash & hash);
/* Compute the hash of the given string. */
Hash hashString(HashType ht, const string & s);
Hash hashString(HashType ht, std::string_view s);
/* Compute the hash of the given file. */
Hash hashFile(HashType ht, const Path & path);
@ -121,9 +118,9 @@ HashResult hashPath(HashType ht, const Path & path,
Hash compressHash(const Hash & hash, unsigned int newSize);
/* Parse a string representing a hash type. */
HashType parseHashType(const string & s);
HashType parseHashType(std::string_view s);
/* Will return nothing on parse error */
std::optional<HashType> parseHashTypeOpt(const string & s);
std::optional<HashType> parseHashTypeOpt(std::string_view s);
/* And the reverse. */
string printHashType(HashType ht);