/*
This file is part of cpp-ethereum.
cpp-ethereum is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
cpp-ethereum is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file MemTrie.cpp
* @author Gav Wood <i@gavwood.com>
* @date 2014
*/
#include "MemTrie.h"
#include <libdevcrypto/TrieCommon.h>
#include <libdevcrypto/SHA3.h>
#include <libethcore/Common.h>
using namespace std;
using namespace dev;
using namespace dev::eth;
namespace dev
{
#define ENABLE_DEBUG_PRINT 0
/*/
#define APPEND_CHILD appendData
/*/
#define APPEND_CHILD appendRaw
/**/
class MemTrieNode
{
public:
MemTrieNode() {}
virtual ~MemTrieNode() {}
virtual std::string const& at(bytesConstRef _key) const = 0;
virtual MemTrieNode* insert(bytesConstRef _key, std::string const& _value) = 0;
virtual MemTrieNode* remove(bytesConstRef _key) = 0;
void putRLP(RLPStream& _parentStream) const;
#if ENABLE_DEBUG_PRINT
void debugPrint(std::string const& _indent = "") const { std::cerr << std::hex << hash256() << ":" << std::dec << std::endl; debugPrintBody(_indent); }
#endif
/// 256-bit hash of the node - this is a SHA-3/256 hash of the RLP of the node.
h256 hash256() const { RLPStream s; makeRLP(s); return dev::sha3(s.out()); }
bytes rlp() const { RLPStream s; makeRLP(s); return s.out(); }
void mark() { m_hash256 = h256(); }
protected:
virtual void makeRLP(RLPStream& _intoStream) const = 0;
#if ENABLE_DEBUG_PRINT
virtual void debugPrintBody(std::string const& _indent = "") const = 0;
#endif
static MemTrieNode* newBranch(bytesConstRef _k1, std::string const& _v1, bytesConstRef _k2, std::string const& _v2);
private:
mutable h256 m_hash256;
};
static const std::string c_nullString;
class TrieExtNode: public MemTrieNode
{
public:
TrieExtNode(bytesConstRef _bytes): m_ext(_bytes.begin(), _bytes.end()) {}
bytes m_ext;
};
class TrieBranchNode: public MemTrieNode
{
public:
TrieBranchNode(std::string const& _value): m_value(_value)
{
memset(m_nodes.data(), 0, sizeof(MemTrieNode*) * 16);
}
TrieBranchNode(byte _i1, MemTrieNode* _n1, std::string const& _value = std::string()): m_value(_value)
{
memset(m_nodes.data(), 0, sizeof(MemTrieNode*) * 16);
m_nodes[_i1] = _n1;
}
TrieBranchNode(byte _i1, MemTrieNode* _n1, byte _i2, MemTrieNode* _n2)
{
memset(m_nodes.data(), 0, sizeof(MemTrieNode*) * 16);
m_nodes[_i1] = _n1;
m_nodes[_i2] = _n2;
}
virtual ~TrieBranchNode()
{
for (auto i: m_nodes)
delete i;
}
#if ENABLE_DEBUG_PRINT
virtual void debugPrintBody(std::string const& _indent) const
{
if (m_value.size())
std::cerr << _indent << "@: " << m_value << std::endl;
for (auto i = 0; i < 16; ++i)
if (m_nodes[i])
{
std::cerr << _indent << std::hex << i << ": " << std::dec;
m_nodes[i]->debugPrint(_indent + " ");
}
}
#endif
virtual std::string const& at(bytesConstRef _key) const override;
virtual MemTrieNode* insert(bytesConstRef _key, std::string const& _value) override;
virtual MemTrieNode* remove(bytesConstRef _key) override;
virtual void makeRLP(RLPStream& _parentStream) const override;
private:
/// @returns (byte)-1 when no active branches, 16 when multiple active and the index of the active branch otherwise.
byte activeBranch() const;
MemTrieNode* rejig();
std::array<MemTrieNode*, 16> m_nodes;
std::string m_value;
};
class TrieLeafNode: public TrieExtNode
{
public:
TrieLeafNode(bytesConstRef _key, std::string const& _value): TrieExtNode(_key), m_value(_value) {}
#if ENABLE_DEBUG_PRINT
virtual void debugPrintBody(std::string const& _indent) const
{
assert(m_value.size());
std::cerr << _indent;
if (m_ext.size())
std::cerr << toHex(m_ext, 1) << ": ";
else
std::cerr << "@: ";
std::cerr << m_value << std::endl;
}
#endif
virtual std::string const& at(bytesConstRef _key) const override { return contains(_key) ? m_value : c_nullString; }
virtual MemTrieNode* insert(bytesConstRef _key, std::string const& _value) override;
virtual MemTrieNode* remove(bytesConstRef _key) override;
virtual void makeRLP(RLPStream& _parentStream) const override;
private:
bool contains(bytesConstRef _key) const { return _key.size() == m_ext.size() && !memcmp(_key.data(), m_ext.data(), _key.size()); }
std::string m_value;
};
class TrieInfixNode: public TrieExtNode
{
public:
TrieInfixNode(bytesConstRef _key, MemTrieNode* _next): TrieExtNode(_key), m_next(_next) {}
virtual ~TrieInfixNode() { delete m_next; }
#if ENABLE_DEBUG_PRINT
virtual void debugPrintBody(std::string const& _indent) const
{
std::cerr << _indent << toHex(m_ext, 1) << ": ";
m_next->debugPrint(_indent + " ");
}
#endif
virtual std::string const& at(bytesConstRef _key) const override { assert(m_next); return contains(_key) ? m_next->at(_key.cropped(m_ext.size())) : c_nullString; }
virtual MemTrieNode* insert(bytesConstRef _key, std::string const& _value) override;
virtual MemTrieNode* remove(bytesConstRef _key) override;
virtual void makeRLP(RLPStream& _parentStream) const override;
private:
bool contains(bytesConstRef _key) const { return _key.size() >= m_ext.size() && !memcmp(_key.data(), m_ext.data(), m_ext.size()); }
MemTrieNode* m_next;
};
void MemTrieNode::putRLP(RLPStream& _parentStream) const
{
RLPStream s;
makeRLP(s);
if (s.out().size() < 32)
_parentStream.APPEND_CHILD(s.out());
else
_parentStream << dev::sha3(s.out());
}
void TrieBranchNode::makeRLP(RLPStream& _intoStream) const
{
_intoStream.appendList(17);
for (auto i: m_nodes)
if (i)
i->putRLP(_intoStream);
else
_intoStream << "";
_intoStream << m_value;
}
void TrieLeafNode::makeRLP(RLPStream& _intoStream) const
{
_intoStream.appendList(2) << hexPrefixEncode(m_ext, true) << m_value;
}
void TrieInfixNode::makeRLP(RLPStream& _intoStream) const
{
assert(m_next);
_intoStream.appendList(2);
_intoStream << hexPrefixEncode(m_ext, false);
m_next->putRLP(_intoStream);
}
MemTrieNode* MemTrieNode::newBranch(bytesConstRef _k1, std::string const& _v1, bytesConstRef _k2, std::string const& _v2)
{
unsigned prefix = commonPrefix(_k1, _k2);
MemTrieNode* ret;
if (_k1.size() == prefix)
ret = new TrieBranchNode(_k2[prefix], new TrieLeafNode(_k2.cropped(prefix + 1), _v2), _v1);
else if (_k2.size() == prefix)
ret = new TrieBranchNode(_k1[prefix], new TrieLeafNode(_k1.cropped(prefix + 1), _v1), _v2);
else // both continue after split
ret = new TrieBranchNode(_k1[prefix], new TrieLeafNode(_k1.cropped(prefix + 1), _v1), _k2[prefix], new TrieLeafNode(_k2.cropped(prefix + 1), _v2));
if (prefix)
// have shared prefix - split.
ret = new TrieInfixNode(_k1.cropped(0, prefix), ret);
return ret;
}
std::string const& TrieBranchNode::at(bytesConstRef _key) const
{
if (_key.empty())
return m_value;
else if (m_nodes[_key[0]] != nullptr)
return m_nodes[_key[0]]->at(_key.cropped(1));
return c_nullString;
}
MemTrieNode* TrieBranchNode::insert(bytesConstRef _key, std::string const& _value)
{
assert(_value.size());
mark();
if (_key.empty())
m_value = _value;
else
if (!m_nodes[_key[0]])
m_nodes[_key[0]] = new TrieLeafNode(_key.cropped(1), _value);
else
m_nodes[_key[0]] = m_nodes[_key[0]]->insert(_key.cropped(1), _value);
return this;
}
MemTrieNode* TrieBranchNode::remove(bytesConstRef _key)
{
if (_key.empty())
if (m_value.size())
{
m_value.clear();
return rejig();
}
else {}
else if (m_nodes[_key[0]] != nullptr)
{
m_nodes[_key[0]] = m_nodes[_key[0]]->remove(_key.cropped(1));
return rejig();
}
return this;
}
MemTrieNode* TrieBranchNode::rejig()
{
mark();
byte n = activeBranch();
if (n == (byte)-1 && m_value.size())
{
// switch to leaf
auto r = new TrieLeafNode(bytesConstRef(), m_value);
delete this;
return r;
}
else if (n < 16 && m_value.empty())
{
// only branching to n...
if (auto b = dynamic_cast<TrieBranchNode*>(m_nodes[n]))
{
// switch to infix
m_nodes[n] = nullptr;
delete this;
return new TrieInfixNode(bytesConstRef(&n, 1), b);
}
else
{
auto x = dynamic_cast<TrieExtNode*>(m_nodes[n]);
assert(x);
// include in child
pushFront(x->m_ext, n);
m_nodes[n] = nullptr;
delete this;
return x;
}
}
return this;
}
byte TrieBranchNode::activeBranch() const
{
byte n = (byte)-1;
for (int i = 0; i < 16; ++i)
if (m_nodes[i] != nullptr)
{
if (n == (byte)-1)
n = (byte)i;
else
return 16;
}
return n;
}
MemTrieNode* TrieInfixNode::insert(bytesConstRef _key, std::string const& _value)
{
assert(_value.size());
mark();
if (contains(_key))
{
m_next = m_next->insert(_key.cropped(m_ext.size()), _value);
return this;
}
else
{
unsigned prefix = commonPrefix(_key, m_ext);
if (prefix)
{
// one infix becomes two infixes, then insert into the second
// instead of pop_front()...
trimFront(m_ext, prefix);
return new TrieInfixNode(_key.cropped(0, prefix), insert(_key.cropped(prefix), _value));
}
else
{
// split here.
auto f = m_ext[0];
trimFront(m_ext, 1);
MemTrieNode* n = m_ext.empty() ? m_next : this;
if (n != this)
{
m_next = nullptr;
delete this;
}
TrieBranchNode* ret = new TrieBranchNode(f, n);
ret->insert(_key, _value);
return ret;
}
}
}
MemTrieNode* TrieInfixNode::remove(bytesConstRef _key)
{
if (contains(_key))
{
mark();
m_next = m_next->remove(_key.cropped(m_ext.size()));
if (auto p = dynamic_cast<TrieExtNode*>(m_next))
{
// merge with child...
m_ext.reserve(m_ext.size() + p->m_ext.size());
for (auto i: p->m_ext)
m_ext.push_back(i);
p->m_ext = m_ext;
p->mark();
m_next = nullptr;
delete this;
return p;
}
if (!m_next)
{
delete this;
return nullptr;
}
}
return this;
}
MemTrieNode* TrieLeafNode::insert(bytesConstRef _key, std::string const& _value)
{
assert(_value.size());
mark();
if (contains(_key))
{
m_value = _value;
return this;
}
else
{
// create new trie.
auto n = MemTrieNode::newBranch(_key, _value, bytesConstRef(&m_ext), m_value);
delete this;
return n;
}
}
MemTrieNode* TrieLeafNode::remove(bytesConstRef _key)
{
if (contains(_key))
{
delete this;
return nullptr;
}
return this;
}
MemTrie::~MemTrie()
{
delete m_root;
}
h256 MemTrie::hash256() const
{
return m_root ? m_root->hash256() : sha3(dev::rlp(bytesConstRef()));
}
bytes MemTrie::rlp() const
{
return m_root ? m_root->rlp() : dev::rlp(bytesConstRef());
}
void MemTrie::debugPrint()
{
#if ENABLE_DEBUG_PRINT
if (m_root)
m_root->debugPrint();
#endif
}
std::string const& MemTrie::at(std::string const& _key) const
{
if (!m_root)
return c_nullString;
auto h = asNibbles(_key);
return m_root->at(bytesConstRef(&h));
}
void MemTrie::insert(std::string const& _key, std::string const& _value)
{
if (_value.empty())
remove(_key);
auto h = asNibbles(_key);
m_root = m_root ? m_root->insert(&h, _value) : new TrieLeafNode(bytesConstRef(&h), _value);
}
void MemTrie::remove(std::string const& _key)
{
if (m_root)
{
auto h = asNibbles(_key);
m_root = m_root->remove(&h);
}
}
}
