Introduce simplfied CBOR encoding for Metadata

This commit is contained in:
Alex Beregszaszi 2019-03-19 16:06:19 +00:00
parent c7824932a4
commit 7babe3dbba

View File

@ -1024,29 +1024,96 @@ string CompilerStack::createMetadata(Contract const& _contract) const
return jsonCompactPrint(meta);
}
class MetadataCBOREncoder
{
public:
void pushBytes(string const& key, bytes const& value)
{
m_entryCount++;
pushTextString(key);
pushByteString(value);
}
void pushString(string const& key, string const& value)
{
m_entryCount++;
pushTextString(key);
pushTextString(value);
}
void pushBool(string const& key, bool value)
{
m_entryCount++;
pushTextString(key);
pushBool(value);
}
bytes serialise() const
{
unsigned size = m_data.size() + 1;
solAssert(size <= 0xffff, "Metadata too large.");
solAssert(m_entryCount <= 0x1f, "Too many map entries.");
// CBOR fixed-length map
bytes ret{static_cast<unsigned char>(0xa0 + m_entryCount)};
// The already encoded key-value pairs
ret += m_data;
// 16-bit big endian length
ret += toCompactBigEndian(size, 2);
return ret;
}
private:
void pushTextString(string const& key)
{
unsigned length = key.size();
if (length < 24)
{
m_data += bytes{static_cast<unsigned char>(0x60 + length)};
m_data += key;
}
else if (length <= 256)
{
m_data += bytes{0x78, static_cast<unsigned char>(length)};
m_data += key;
}
else
solAssert(false, "Text string too large.");
}
void pushByteString(bytes const& key)
{
unsigned length = key.size();
if (length < 24)
{
m_data += bytes{static_cast<unsigned char>(0x40 + length)};
m_data += key;
}
else if (length <= 256)
{
m_data += bytes{0x58, static_cast<unsigned char>(length)};
m_data += key;
}
else
solAssert(false, "Byte string too large.");
}
void pushBool(bool value)
{
if (value)
m_data += bytes{0xf5};
else
m_data += bytes{0xf4};
}
unsigned m_entryCount = 0;
bytes m_data;
};
bytes CompilerStack::createCBORMetadata(string const& _metadata, bool _experimentalMode)
{
bytes cborEncodedHash =
// CBOR-encoding of the key "bzzr0"
bytes{0x65, 'b', 'z', 'z', 'r', '0'}+
// CBOR-encoding of the hash
bytes{0x58, 0x20} + dev::swarmHash(_metadata).asBytes();
bytes cborEncodedMetadata;
MetadataCBOREncoder encoder;
encoder.pushBytes("bzzr0", dev::swarmHash(_metadata).asBytes());
if (_experimentalMode)
cborEncodedMetadata =
// CBOR-encoding of {"bzzr0": dev::swarmHash(metadata), "experimental": true}
bytes{0xa2} +
cborEncodedHash +
bytes{0x6c, 'e', 'x', 'p', 'e', 'r', 'i', 'm', 'e', 'n', 't', 'a', 'l', 0xf5};
else
cborEncodedMetadata =
// CBOR-encoding of {"bzzr0": dev::swarmHash(metadata)}
bytes{0xa1} +
cborEncodedHash;
solAssert(cborEncodedMetadata.size() <= 0xffff, "Metadata too large");
// 16-bit big endian length
cborEncodedMetadata += toCompactBigEndian(cborEncodedMetadata.size(), 2);
return cborEncodedMetadata;
encoder.pushBool("experimental", true);
return encoder.serialise();
}
string CompilerStack::computeSourceMapping(eth::AssemblyItems const& _items) const