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Add spentness flag to pegin coins
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@stevenroose
stevenroose committed Jan 2, 2019
1 parent 0d07d21 commit f4adb46
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Showing 7 changed files with 134 additions and 19 deletions.
82 changes: 76 additions & 6 deletions src/coins.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,8 @@ uint256 CCoinsView::GetBestBlock() const { return uint256(); }
std::vector<uint256> CCoinsView::GetHeadBlocks() const { return std::vector<uint256>(); }
bool CCoinsView::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) { return false; }
CCoinsViewCursor *CCoinsView::Cursor() const { return nullptr; }
// ELEMENTS:
bool CCoinsView::IsPeginSpent(const std::pair<uint256, COutPoint> &outpoint) const { return false; }

bool CCoinsView::HaveCoin(const COutPoint &outpoint) const
{
Expand All @@ -28,6 +30,8 @@ void CCoinsViewBacked::SetBackend(CCoinsView &viewIn) { base = &viewIn; }
bool CCoinsViewBacked::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) { return base->BatchWrite(mapCoins, hashBlock); }
CCoinsViewCursor *CCoinsViewBacked::Cursor() const { return base->Cursor(); }
size_t CCoinsViewBacked::EstimateSize() const { return base->EstimateSize(); }
// ELEMENTS:
bool CCoinsViewBacked::IsPeginSpent(const std::pair<uint256, COutPoint> &outpoint) const { return base->IsPeginSpent(outpoint); }

SaltedOutpointHasher::SaltedOutpointHasher() : k0(GetRand(std::numeric_limits<uint64_t>::max())), k1(GetRand(std::numeric_limits<uint64_t>::max())) {}

Expand Down Expand Up @@ -141,6 +145,56 @@ bool CCoinsViewCache::HaveCoinInCache(const COutPoint &outpoint) const {
return (it != cacheCoins.end() && !it->second.coin.IsSpent());
}

//
// ELEMENTS:

bool CCoinsViewCache::IsPeginSpent(const std::pair<uint256, COutPoint> &outpoint) const {
assert(!outpoint.second.hash.IsNull());
assert(!outpoint.first.IsNull());

CCoinsMap::iterator it = cacheCoins.find(outpoint);
if (it == cacheCoins.end()) {
bool inserted;
std::tie(it, inserted) = cacheCoins.emplace(std::piecewise_construct,
std::forward_as_tuple(outpoint), std::tuple<>());
it->second.peginSpent = base->IsPeginSpent(outpoint);
it->second.flags |= CCoinsCacheEntry::PEGIN;
if (!it->second.peginSpent)
it->second.flags |= CCoinsCacheEntry::FRESH;
}
return it->second.peginSpent;
}

void CCoinsViewCache::SetPeginSpent(const std::pair<uint256, COutPoint> &outpoint, bool fSpent) {
assert(!outpoint.second.hash.IsNull());
assert(!outpoint.first.IsNull());

CCoinsMap::iterator it = cacheCoins.find(outpoint);

bool hadSpent;
if (it == cacheCoins.end())
hadSpent = base->IsPeginSpent(outpoint);
else
hadSpent = it->second.peginSpent;

// If we aren't changing spentness, dont do anything at all
if (hadSpent == fSpent)
return;

if (it == cacheCoins.end()) {
bool inserted;
std::tie(it, inserted) = cacheCoins.emplace(std::piecewise_construct,
std::forward_as_tuple(outpoint), std::tuple<>());
if (!hadSpent)
it->second.flags = CCoinsCacheEntry::FRESH;
}
it->second.peginSpent = fSpent;
it->second.flags |= CCoinsCacheEntry::PEGIN | CCoinsCacheEntry::DIRTY;
}

// END ELEMENTS
//

uint256 CCoinsViewCache::GetBestBlock() const {
if (hashBlock.IsNull())
hashBlock = base->GetBestBlock();
Expand All @@ -157,17 +211,28 @@ bool CCoinsViewCache::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlockIn
if (!(it->second.flags & CCoinsCacheEntry::DIRTY)) {
continue;
}

// ELEMENTS:
bool fIsPegin = it->second.flags & CCoinsCacheEntry::PEGIN;

CCoinsMap::iterator itUs = cacheCoins.find(it->first);
if (itUs == cacheCoins.end()) {
// The parent cache does not have an entry, while the child does
// We can ignore it if it's both FRESH and pruned in the child
if (!(it->second.flags & CCoinsCacheEntry::FRESH && it->second.coin.IsSpent())) {
// We can ignore it if it's both FRESH and {pruned, spent pegin} in the child
if (!((it->second.flags & CCoinsCacheEntry::FRESH) &&
(( fIsPegin && !it->second.peginSpent) ||
(!fIsPegin && it->second.coin.IsSpent())))) {
// Otherwise we will need to create it in the parent
// and move the data up and mark it as dirty
CCoinsCacheEntry& entry = cacheCoins[it->first];
entry.coin = std::move(it->second.coin);
cachedCoinsUsage += entry.coin.DynamicMemoryUsage();
entry.flags = CCoinsCacheEntry::DIRTY;
if (fIsPegin) {
entry.peginSpent = it->second.peginSpent;
entry.flags |= CCoinsCacheEntry::PEGIN;
} else {
entry.coin = it->second.coin;
}
cachedCoinsUsage += entry.coin.DynamicMemoryUsage();
// We can mark it FRESH in the parent if it was FRESH in the child
// Otherwise it might have just been flushed from the parent's cache
// and already exist in the grandparent
Expand All @@ -185,7 +250,8 @@ bool CCoinsViewCache::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlockIn
}

// Found the entry in the parent cache
if ((itUs->second.flags & CCoinsCacheEntry::FRESH) && it->second.coin.IsSpent()) {
if ((itUs->second.flags & CCoinsCacheEntry::FRESH) &&
((fIsPegin && !it->second.peginSpent) || (!fIsPegin && it->second.coin.IsSpent()))) {
// The grandparent does not have an entry, and the child is
// modified and being pruned. This means we can just delete
// it from the parent.
Expand All @@ -194,7 +260,11 @@ bool CCoinsViewCache::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlockIn
} else {
// A normal modification.
cachedCoinsUsage -= itUs->second.coin.DynamicMemoryUsage();
itUs->second.coin = std::move(it->second.coin);
if (fIsPegin) {
itUs->second.peginSpent = it->second.peginSpent;
} else {
itUs->second.coin = it->second.coin;
}
cachedCoinsUsage += itUs->second.coin.DynamicMemoryUsage();
itUs->second.flags |= CCoinsCacheEntry::DIRTY;
// NOTE: It is possible the child has a FRESH flag here in
Expand Down
13 changes: 13 additions & 0 deletions src/coins.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,8 @@ struct CCoinsCacheEntry
{
Coin coin; // The actual cached data.
unsigned char flags;
// ELEMENTS:
bool peginSpent;

enum Flags {
DIRTY = (1 << 0), // This cache entry is potentially different from the version in the parent view.
Expand All @@ -94,6 +96,8 @@ struct CCoinsCacheEntry
* flush the changes to the parent cache. It is always safe to
* not mark FRESH if that condition is not guaranteed.
*/
// ELEMENTS:
PEGIN = (1 << 2), // represents a pegin (coins is actually empty/useless, look at peginSpent instead)
};

CCoinsCacheEntry() : flags(0) {}
Expand Down Expand Up @@ -159,6 +163,10 @@ class CCoinsView
//! Just check whether a given outpoint is unspent.
virtual bool HaveCoin(const COutPoint &outpoint) const;

// ELEMENTS:
//! Check if a given pegin has been spent
virtual bool IsPeginSpent(const std::pair<uint256, COutPoint> &outpoint) const;

//! Retrieve the block hash whose state this CCoinsView currently represents
virtual uint256 GetBestBlock() const;

Expand Down Expand Up @@ -199,6 +207,8 @@ class CCoinsViewBacked : public CCoinsView
bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) override;
CCoinsViewCursor *Cursor() const override;
size_t EstimateSize() const override;
// ELEMENTS:
bool IsPeginSpent(const std::pair<uint256, COutPoint> &outpoint) const override;
};


Expand Down Expand Up @@ -233,6 +243,9 @@ class CCoinsViewCache : public CCoinsViewBacked
CCoinsViewCursor* Cursor() const override {
throw std::logic_error("CCoinsViewCache cursor iteration not supported.");
}
// ELEMENTS:
bool IsPeginSpent(const std::pair<uint256, COutPoint> &outpoint) const override;
void SetPeginSpent(const std::pair<uint256, COutPoint> &outpoint, bool fSpent);

/**
* Check if we have the given utxo already loaded in this cache.
Expand Down
16 changes: 8 additions & 8 deletions src/test/coins_tests.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@

#include <boost/test/unit_test.hpp>

int ApplyTxInUndo(Coin&& undo, CCoinsViewCache& view, const COutPoint& out);
int ApplyTxInUndo(Coin&& undo, CCoinsViewCache& view, const COutPoint& out, const CTxIn& txin, const CScriptWitness& pegin_witness);
void UpdateCoins(const CTransaction& tx, CCoinsViewCache& inputs, CTxUndo &txundo, int nHeight);

namespace
Expand Down Expand Up @@ -57,10 +57,10 @@ class CCoinsViewTest : public CCoinsView
for (CCoinsMap::iterator it = mapCoins.begin(); it != mapCoins.end(); ) {
if (it->second.flags & CCoinsCacheEntry::DIRTY) {
// Same optimization used in CCoinsViewDB is to only write dirty entries.
map_[it->first] = it->second.coin;
map_[it->first.second] = it->second.coin;
if (it->second.coin.IsSpent() && InsecureRandRange(3) == 0) {
// Randomly delete empty entries on write.
map_.erase(it->first);
map_.erase(it->first.second);
}
}
mapCoins.erase(it++);
Expand Down Expand Up @@ -407,7 +407,7 @@ BOOST_AUTO_TEST_CASE(updatecoins_simulation_test)
if (!tx.IsCoinBase()) {
const COutPoint &out = tx.vin[0].prevout;
Coin coin = undo.vprevout[0];
ApplyTxInUndo(std::move(coin), *(stack.back()), out);
ApplyTxInUndo(std::move(coin), *(stack.back()), out, tx.vin[0], tx.vin[0].m_pegin_witness);
}
// Store as a candidate for reconnection
disconnected_coins.insert(utxod->first);
Expand Down Expand Up @@ -525,7 +525,7 @@ BOOST_AUTO_TEST_CASE(ccoins_serialization)
}
}

const static COutPoint OUTPOINT;
const static std::pair<uint256, COutPoint> OUTPOINT;
const static CAmount PRUNED = -1;
const static CAmount ABSENT = -2;
const static CAmount FAIL = -3;
Expand Down Expand Up @@ -608,7 +608,7 @@ class SingleEntryCacheTest
static void CheckAccessCoin(CAmount base_value, CAmount cache_value, CAmount expected_value, char cache_flags, char expected_flags)
{
SingleEntryCacheTest test(base_value, cache_value, cache_flags);
test.cache.AccessCoin(OUTPOINT);
test.cache.AccessCoin(OUTPOINT.second);
test.cache.SelfTest();

CAmount result_value;
Expand Down Expand Up @@ -659,7 +659,7 @@ BOOST_AUTO_TEST_CASE(ccoins_access)
static void CheckSpendCoins(CAmount base_value, CAmount cache_value, CAmount expected_value, char cache_flags, char expected_flags)
{
SingleEntryCacheTest test(base_value, cache_value, cache_flags);
test.cache.SpendCoin(OUTPOINT);
test.cache.SpendCoin(OUTPOINT.second);
test.cache.SelfTest();

CAmount result_value;
Expand Down Expand Up @@ -716,7 +716,7 @@ static void CheckAddCoinBase(CAmount base_value, CAmount cache_value, CAmount mo
try {
CTxOut output;
output.nValue = modify_value;
test.cache.AddCoin(OUTPOINT, Coin(std::move(output), 1, coinbase), coinbase);
test.cache.AddCoin(OUTPOINT.second, Coin(std::move(output), 1, coinbase), coinbase);
test.cache.SelfTest();
GetCoinsMapEntry(test.cache.map(), result_value, result_flags);
} catch (std::logic_error& e) {
Expand Down
31 changes: 26 additions & 5 deletions src/txdb.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,9 @@ static const char DB_FLAG = 'F';
static const char DB_REINDEX_FLAG = 'R';
static const char DB_LAST_BLOCK = 'l';

// ELEMENTS:
static const char DB_PEGIN_FLAG = 'w';

namespace {

struct CoinEntry {
Expand Down Expand Up @@ -68,6 +71,11 @@ bool CCoinsViewDB::HaveCoin(const COutPoint &outpoint) const {
return db.Exists(CoinEntry(&outpoint));
}

// ELEMENTS:
bool CCoinsViewDB::IsPeginSpent(const std::pair<uint256, COutPoint> &outpoint) const {
return db.Exists(std::make_pair(DB_PEGIN_FLAG, outpoint));
}

uint256 CCoinsViewDB::GetBestBlock() const {
uint256 hashBestChain;
if (!db.Read(DB_BEST_BLOCK, hashBestChain))
Expand Down Expand Up @@ -110,11 +118,24 @@ bool CCoinsViewDB::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) {

for (CCoinsMap::iterator it = mapCoins.begin(); it != mapCoins.end();) {
if (it->second.flags & CCoinsCacheEntry::DIRTY) {
CoinEntry entry(&it->first);
if (it->second.coin.IsSpent())
batch.Erase(entry);
else
batch.Write(entry, it->second.coin);
// ELEMENTS:
if (it->second.flags & CCoinsCacheEntry::PEGIN) {
if (!it->second.peginSpent) {
batch.Erase(std::make_pair(DB_PEGIN_FLAG, it->first));
} else {
// Once spent, we don't care about the entry data, so we store
// a static byte to indicate spentness.
batch.Write(std::make_pair(DB_PEGIN_FLAG, it->first), '1');
}
} else {
// Non-pegin entries are stored the same way as in Core.
CoinEntry entry(&it->first.second);
if (it->second.coin.IsSpent()) {
batch.Erase(entry);
} else {
batch.Write(entry, it->second.coin);
}
}
changed++;
}
count++;
Expand Down
2 changes: 2 additions & 0 deletions src/txdb.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,8 @@ class CCoinsViewDB final : public CCoinsView
std::vector<uint256> GetHeadBlocks() const override;
bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) override;
CCoinsViewCursor *Cursor() const override;
// ELEMENTS:
bool IsPeginSpent(const std::pair<uint256, COutPoint> &outpoint) const override;

//! Attempt to update from an older database format. Returns whether an error occurred.
bool Upgrade();
Expand Down
5 changes: 5 additions & 0 deletions src/txmempool.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -898,6 +898,11 @@ bool CCoinsViewMemPool::GetCoin(const COutPoint &outpoint, Coin &coin) const {
return base->GetCoin(outpoint, coin);
}

// ELEMENTS:
bool CCoinsViewMemPool::IsPeginSpent(const std::pair<uint256, COutPoint> &outpoint) const {
return mempool.mapPeginsSpentToTxid.count(outpoint) || base->IsPeginSpent(outpoint);
}

size_t CTxMemPool::DynamicMemoryUsage() const {
LOCK(cs);
// Estimate the overhead of mapTx to be 12 pointers + an allocation, as no exact formula for boost::multi_index_contained is implemented.
Expand Down
4 changes: 4 additions & 0 deletions src/txmempool.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -499,6 +499,8 @@ class CTxMemPool
const setEntries & GetMemPoolParents(txiter entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
const setEntries & GetMemPoolChildren(txiter entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
uint64_t CalculateDescendantMaximum(txiter entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
// ELEMENTS:
std::map<std::pair<uint256, COutPoint>, uint256> mapPeginsSpentToTxid;
private:
typedef std::map<txiter, setEntries, CompareIteratorByHash> cacheMap;

Expand Down Expand Up @@ -711,6 +713,8 @@ class CCoinsViewMemPool : public CCoinsViewBacked
public:
CCoinsViewMemPool(CCoinsView* baseIn, const CTxMemPool& mempoolIn);
bool GetCoin(const COutPoint &outpoint, Coin &coin) const override;
// ELEMENTS:
bool IsPeginSpent(const std::pair<uint256, COutPoint> &outpoint) const override;
};

/**
Expand Down

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