Files
xahaud/src/ripple/shamap/impl/SHAMapDelta.cpp
Howard Hinnant 26bfeb1319 Replace Serializer with Blob in SHAMapItem:
* This helps decouples SHAMap and Serializer.
* Restyle data member names.
* Rename getTag() to key().
2015-07-02 15:06:09 -07:00

268 lines
10 KiB
C++

//------------------------------------------------------------------------------
/*
This file is part of rippled: https://github.com/ripple/rippled
Copyright (c) 2012, 2013 Ripple Labs Inc.
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#include <BeastConfig.h>
#include <ripple/shamap/SHAMap.h>
namespace ripple {
// This code is used to compare another node's transaction tree
// to our own. It returns a map containing all items that are different
// between two SHA maps. It is optimized not to descend down tree
// branches with the same branch hash. A limit can be passed so
// that we will abort early if a node sends a map to us that
// makes no sense at all. (And our sync algorithm will avoid
// synchronizing matching branches too.)
bool SHAMap::walkBranch (SHAMapAbstractNode* node,
std::shared_ptr<SHAMapItem const> const& otherMapItem,
bool isFirstMap,Delta& differences, int& maxCount) const
{
// Walk a branch of a SHAMap that's matched by an empty branch or single item in the other map
std::stack <SHAMapAbstractNode*, std::vector<SHAMapAbstractNode*>> nodeStack;
nodeStack.push (node);
bool emptyBranch = !otherMapItem;
while (!nodeStack.empty ())
{
node = nodeStack.top ();
nodeStack.pop ();
if (node->isInner ())
{
// This is an inner node, add all non-empty branches
auto inner = static_cast<SHAMapInnerNode*>(node);
for (int i = 0; i < 16; ++i)
if (!inner->isEmptyBranch (i))
nodeStack.push ({descendThrow (inner, i)});
}
else
{
// This is a leaf node, process its item
auto item = static_cast<SHAMapTreeNode*>(node)->peekItem();
if (emptyBranch || (item->key() != otherMapItem->key()))
{
// unmatched
if (isFirstMap)
differences.insert (std::make_pair (item->key(),
DeltaRef (item, std::shared_ptr<SHAMapItem const> ())));
else
differences.insert (std::make_pair (item->key(),
DeltaRef (std::shared_ptr<SHAMapItem const> (), item)));
if (--maxCount <= 0)
return false;
}
else if (item->peekData () != otherMapItem->peekData ())
{
// non-matching items with same tag
if (isFirstMap)
differences.insert (std::make_pair (item->key(),
DeltaRef (item, otherMapItem)));
else
differences.insert (std::make_pair (item->key(),
DeltaRef (otherMapItem, item)));
if (--maxCount <= 0)
return false;
emptyBranch = true;
}
else
{
// exact match
emptyBranch = true;
}
}
}
if (!emptyBranch)
{
// otherMapItem was unmatched, must add
if (isFirstMap) // this is first map, so other item is from second
differences.insert(std::make_pair(otherMapItem->key(),
DeltaRef(std::shared_ptr<SHAMapItem const>(),
otherMapItem)));
else
differences.insert(std::make_pair(otherMapItem->key(),
DeltaRef(otherMapItem, std::shared_ptr<SHAMapItem const>())));
if (--maxCount <= 0)
return false;
}
return true;
}
bool
SHAMap::compare (std::shared_ptr<SHAMap> const& otherMap,
Delta& differences, int maxCount) const
{
// compare two hash trees, add up to maxCount differences to the difference table
// return value: true=complete table of differences given, false=too many differences
// throws on corrupt tables or missing nodes
// CAUTION: otherMap is not locked and must be immutable
assert (isValid () && otherMap && otherMap->isValid ());
if (getHash () == otherMap->getHash ())
return true;
using StackEntry = std::pair <SHAMapAbstractNode*, SHAMapAbstractNode*>;
std::stack <StackEntry, std::vector<StackEntry>> nodeStack; // track nodes we've pushed
nodeStack.push ({root_.get(), otherMap->root_.get()});
while (!nodeStack.empty ())
{
SHAMapAbstractNode* ourNode = nodeStack.top().first;
SHAMapAbstractNode* otherNode = nodeStack.top().second;
nodeStack.pop ();
if (!ourNode || !otherNode)
{
assert (false);
throw SHAMapMissingNode (type_, uint256 ());
}
if (ourNode->isLeaf () && otherNode->isLeaf ())
{
// two leaves
auto ours = static_cast<SHAMapTreeNode*>(ourNode);
auto other = static_cast<SHAMapTreeNode*>(otherNode);
if (ours->peekItem()->key() == other->peekItem()->key())
{
if (ours->peekItem()->peekData () != other->peekItem()->peekData ())
{
differences.insert (std::make_pair (ours->peekItem()->key(),
DeltaRef (ours->peekItem (),
other->peekItem ())));
if (--maxCount <= 0)
return false;
}
}
else
{
differences.insert (std::make_pair(ours->peekItem()->key(),
DeltaRef(ours->peekItem(),
std::shared_ptr<SHAMapItem const>())));
if (--maxCount <= 0)
return false;
differences.insert(std::make_pair(other->peekItem()->key(),
DeltaRef(std::shared_ptr<SHAMapItem const>(), other->peekItem ())));
if (--maxCount <= 0)
return false;
}
}
else if (ourNode->isInner () && otherNode->isLeaf ())
{
auto ours = static_cast<SHAMapInnerNode*>(ourNode);
auto other = static_cast<SHAMapTreeNode*>(otherNode);
if (!walkBranch (ours, other->peekItem (),
true, differences, maxCount))
return false;
}
else if (ourNode->isLeaf () && otherNode->isInner ())
{
auto ours = static_cast<SHAMapTreeNode*>(ourNode);
auto other = static_cast<SHAMapInnerNode*>(otherNode);
if (!otherMap->walkBranch (other, ours->peekItem (),
false, differences, maxCount))
return false;
}
else if (ourNode->isInner () && otherNode->isInner ())
{
auto ours = static_cast<SHAMapInnerNode*>(ourNode);
auto other = static_cast<SHAMapInnerNode*>(otherNode);
for (int i = 0; i < 16; ++i)
if (ours->getChildHash (i) != other->getChildHash (i))
{
if (other->isEmptyBranch (i))
{
// We have a branch, the other tree does not
SHAMapAbstractNode* iNode = descendThrow (ours, i);
if (!walkBranch (iNode,
std::shared_ptr<SHAMapItem const> (), true,
differences, maxCount))
return false;
}
else if (ours->isEmptyBranch (i))
{
// The other tree has a branch, we do not
SHAMapAbstractNode* iNode =
otherMap->descendThrow(other, i);
if (!otherMap->walkBranch (iNode,
std::shared_ptr<SHAMapItem const>(),
false, differences, maxCount))
return false;
}
else // The two trees have different non-empty branches
nodeStack.push ({descendThrow (ours, i),
otherMap->descendThrow (other, i)});
}
}
else
assert (false);
}
return true;
}
void SHAMap::walkMap (std::vector<SHAMapMissingNode>& missingNodes, int maxMissing) const
{
if (!root_->isInner ()) // root_ is only node, and we have it
return;
using StackEntry = std::shared_ptr<SHAMapInnerNode>;
std::stack <StackEntry, std::vector <StackEntry>> nodeStack;
nodeStack.push (std::static_pointer_cast<SHAMapInnerNode>(root_));
while (!nodeStack.empty ())
{
std::shared_ptr<SHAMapInnerNode> node = std::move (nodeStack.top());
nodeStack.pop ();
for (int i = 0; i < 16; ++i)
{
if (!node->isEmptyBranch (i))
{
std::shared_ptr<SHAMapAbstractNode> nextNode = descendNoStore (node, i);
if (nextNode)
{
if (nextNode->isInner ())
nodeStack.push(
std::static_pointer_cast<SHAMapInnerNode>(nextNode));
}
else
{
missingNodes.emplace_back (type_, node->getChildHash (i));
if (--maxMissing <= 0)
return;
}
}
}
}
}
} // ripple