From 509cb006d514cece5ab7680094f033c8dc8a2318 Mon Sep 17 00:00:00 2001
From: "Wladimir J. van der Laan" <laanwj@gmail.com>
Date: Mon, 28 Mar 2016 18:18:30 +0200
Subject: txdb: Add Cursor() method to CCoinsView to iterate over UTXO set
Add a method Cursor() to CCoinsView that returns a cursor which can be
used to iterate over the whole UTXO set.
- rpc: Change gettxoutsetinfo to use new Cursor method
- txdb: Remove GetStats method - Now that GetStats is implemented in
terms of Cursor, remove it.
---
src/coins.cpp | 8 +++--
src/coins.h | 33 ++++++++++++--------
src/rpc/blockchain.cpp | 58 ++++++++++++++++++++++++++++++++++-
src/test/coins_tests.cpp | 2 --
src/txdb.cpp | 78 +++++++++++++++++++++++++-----------------------
src/txdb.h | 26 +++++++++++++++-
6 files changed, 148 insertions(+), 57 deletions(-)
diff --git a/src/coins.cpp b/src/coins.cpp
index 877fb8b26c..1c329740b4 100644
--- a/src/coins.cpp
+++ b/src/coins.cpp
@@ -45,7 +45,7 @@ bool CCoinsView::GetCoins(const uint256 &txid, CCoins &coins) const { return fal
bool CCoinsView::HaveCoins(const uint256 &txid) const { return false; }
uint256 CCoinsView::GetBestBlock() const { return uint256(); }
bool CCoinsView::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) { return false; }
-bool CCoinsView::GetStats(CCoinsStats &stats) const { return false; }
+CCoinsViewCursor *CCoinsView::Cursor() const { return 0; }
CCoinsViewBacked::CCoinsViewBacked(CCoinsView *viewIn) : base(viewIn) { }
@@ -54,7 +54,7 @@ bool CCoinsViewBacked::HaveCoins(const uint256 &txid) const { return base->HaveC
uint256 CCoinsViewBacked::GetBestBlock() const { return base->GetBestBlock(); }
void CCoinsViewBacked::SetBackend(CCoinsView &viewIn) { base = &viewIn; }
bool CCoinsViewBacked::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock) { return base->BatchWrite(mapCoins, hashBlock); }
-bool CCoinsViewBacked::GetStats(CCoinsStats &stats) const { return base->GetStats(stats); }
+CCoinsViewCursor *CCoinsViewBacked::Cursor() const { return base->Cursor(); }
CCoinsKeyHasher::CCoinsKeyHasher() : salt(GetRandHash()) {}
@@ -300,3 +300,7 @@ CCoinsModifier::~CCoinsModifier()
cache.cachedCoinsUsage += it->second.coins.DynamicMemoryUsage();
}
}
+
+CCoinsViewCursor::~CCoinsViewCursor()
+{
+}
diff --git a/src/coins.h b/src/coins.h
index d297cae1aa..d72f885473 100644
--- a/src/coins.h
+++ b/src/coins.h
@@ -297,19 +297,26 @@ struct CCoinsCacheEntry
typedef boost::unordered_map<uint256, CCoinsCacheEntry, CCoinsKeyHasher> CCoinsMap;
-struct CCoinsStats
+/** Cursor for iterating over CoinsView state */
+class CCoinsViewCursor
{
- int nHeight;
- uint256 hashBlock;
- uint64_t nTransactions;
- uint64_t nTransactionOutputs;
- uint64_t nSerializedSize;
- uint256 hashSerialized;
- CAmount nTotalAmount;
+public:
+ CCoinsViewCursor(const uint256 &hashBlockIn): hashBlock(hashBlockIn) {}
+ virtual ~CCoinsViewCursor();
- CCoinsStats() : nHeight(0), nTransactions(0), nTransactionOutputs(0), nSerializedSize(0), nTotalAmount(0) {}
-};
+ virtual bool GetKey(uint256 &key) const = 0;
+ virtual bool GetValue(CCoins &coins) const = 0;
+ /* Don't care about GetKeySize here */
+ virtual unsigned int GetValueSize() const = 0;
+ virtual bool Valid() const = 0;
+ virtual void Next() = 0;
+
+ //! Get best block at the time this cursor was created
+ const uint256 &GetBestBlock() const { return hashBlock; }
+private:
+ uint256 hashBlock;
+};
/** Abstract view on the open txout dataset. */
class CCoinsView
@@ -329,8 +336,8 @@ public:
//! The passed mapCoins can be modified.
virtual bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock);
- //! Calculate statistics about the unspent transaction output set
- virtual bool GetStats(CCoinsStats &stats) const;
+ //! Get a cursor to iterate over the whole state
+ virtual CCoinsViewCursor *Cursor() const;
//! As we use CCoinsViews polymorphically, have a virtual destructor
virtual ~CCoinsView() {}
@@ -350,7 +357,7 @@ public:
uint256 GetBestBlock() const;
void SetBackend(CCoinsView &viewIn);
bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock);
- bool GetStats(CCoinsStats &stats) const;
+ CCoinsViewCursor *Cursor() const;
};
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 34637b9f7e..8dbfbd5ff8 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -18,11 +18,14 @@
#include "txmempool.h"
#include "util.h"
#include "utilstrencodings.h"
+#include "hash.h"
#include <stdint.h>
#include <univalue.h>
+#include <boost/thread/thread.hpp> // boost::thread::interrupt
+
using namespace std;
extern void TxToJSON(const CTransaction& tx, const uint256 hashBlock, UniValue& entry);
@@ -432,6 +435,59 @@ UniValue getblock(const UniValue& params, bool fHelp)
return blockToJSON(block, pblockindex);
}
+struct CCoinsStats
+{
+ int nHeight;
+ uint256 hashBlock;
+ uint64_t nTransactions;
+ uint64_t nTransactionOutputs;
+ uint64_t nSerializedSize;
+ uint256 hashSerialized;
+ CAmount nTotalAmount;
+
+ CCoinsStats() : nHeight(0), nTransactions(0), nTransactionOutputs(0), nSerializedSize(0), nTotalAmount(0) {}
+};
+
+//! Calculate statistics about the unspent transaction output set
+static bool GetUTXOStats(CCoinsView *view, CCoinsStats &stats)
+{
+ boost::scoped_ptr<CCoinsViewCursor> pcursor(view->Cursor());
+
+ CHashWriter ss(SER_GETHASH, PROTOCOL_VERSION);
+ stats.hashBlock = pcursor->GetBestBlock();
+ {
+ LOCK(cs_main);
+ stats.nHeight = mapBlockIndex.find(stats.hashBlock)->second->nHeight;
+ }
+ ss << stats.hashBlock;
+ CAmount nTotalAmount = 0;
+ while (pcursor->Valid()) {
+ boost::this_thread::interruption_point();
+ uint256 key;
+ CCoins coins;
+ if (pcursor->GetKey(key) && pcursor->GetValue(coins)) {
+ stats.nTransactions++;
+ for (unsigned int i=0; i<coins.vout.size(); i++) {
+ const CTxOut &out = coins.vout[i];
+ if (!out.IsNull()) {
+ stats.nTransactionOutputs++;
+ ss << VARINT(i+1);
+ ss << out;
+ nTotalAmount += out.nValue;
+ }
+ }
+ stats.nSerializedSize += 32 + pcursor->GetValueSize();
+ ss << VARINT(0);
+ } else {
+ return error("%s: unable to read value", __func__);
+ }
+ pcursor->Next();
+ }
+ stats.hashSerialized = ss.GetHash();
+ stats.nTotalAmount = nTotalAmount;
+ return true;
+}
+
UniValue gettxoutsetinfo(const UniValue& params, bool fHelp)
{
if (fHelp || params.size() != 0)
@@ -458,7 +514,7 @@ UniValue gettxoutsetinfo(const UniValue& params, bool fHelp)
CCoinsStats stats;
FlushStateToDisk();
- if (pcoinsTip->GetStats(stats)) {
+ if (GetUTXOStats(pcoinsTip, stats)) {
ret.push_back(Pair("height", (int64_t)stats.nHeight));
ret.push_back(Pair("bestblock", stats.hashBlock.GetHex()));
ret.push_back(Pair("transactions", (int64_t)stats.nTransactions));
diff --git a/src/test/coins_tests.cpp b/src/test/coins_tests.cpp
index 3fe536f91a..48e3c8ed8e 100644
--- a/src/test/coins_tests.cpp
+++ b/src/test/coins_tests.cpp
@@ -61,8 +61,6 @@ public:
hashBestBlock_ = hashBlock;
return true;
}
-
- bool GetStats(CCoinsStats& stats) const { return false; }
};
class CCoinsViewCacheTest : public CCoinsViewCache
diff --git a/src/txdb.cpp b/src/txdb.cpp
index f99e11f26e..be86cceeb3 100644
--- a/src/txdb.cpp
+++ b/src/txdb.cpp
@@ -94,50 +94,52 @@ bool CBlockTreeDB::ReadLastBlockFile(int &nFile) {
return Read(DB_LAST_BLOCK, nFile);
}
-bool CCoinsViewDB::GetStats(CCoinsStats &stats) const {
+CCoinsViewCursor *CCoinsViewDB::Cursor() const
+{
+ CCoinsViewDBCursor *i = new CCoinsViewDBCursor(const_cast<CDBWrapper*>(&db)->NewIterator(), GetBestBlock());
/* It seems that there are no "const iterators" for LevelDB. Since we
only need read operations on it, use a const-cast to get around
that restriction. */
- boost::scoped_ptr<CDBIterator> pcursor(const_cast<CDBWrapper*>(&db)->NewIterator());
- pcursor->Seek(DB_COINS);
+ i->pcursor->Seek(DB_COINS);
+ // Cache key of first record
+ i->pcursor->GetKey(i->keyTmp);
+ return i;
+}
- CHashWriter ss(SER_GETHASH, PROTOCOL_VERSION);
- stats.hashBlock = GetBestBlock();
- ss << stats.hashBlock;
- CAmount nTotalAmount = 0;
- while (pcursor->Valid()) {
- boost::this_thread::interruption_point();
- std::pair<char, uint256> key;
- CCoins coins;
- if (pcursor->GetKey(key) && key.first == DB_COINS) {
- if (pcursor->GetValue(coins)) {
- stats.nTransactions++;
- for (unsigned int i=0; i<coins.vout.size(); i++) {
- const CTxOut &out = coins.vout[i];
- if (!out.IsNull()) {
- stats.nTransactionOutputs++;
- ss << VARINT(i+1);
- ss << out;
- nTotalAmount += out.nValue;
- }
- }
- stats.nSerializedSize += 32 + pcursor->GetValueSize();
- ss << VARINT(0);
- } else {
- return error("CCoinsViewDB::GetStats() : unable to read value");
- }
- } else {
- break;
- }
- pcursor->Next();
+bool CCoinsViewDBCursor::GetKey(uint256 &key) const
+{
+ // Return cached key
+ if (keyTmp.first == DB_COINS) {
+ key = keyTmp.second;
+ return true;
}
- {
- LOCK(cs_main);
- stats.nHeight = mapBlockIndex.find(stats.hashBlock)->second->nHeight;
+ return false;
+}
+
+bool CCoinsViewDBCursor::GetValue(CCoins &coins) const
+{
+ return pcursor->GetValue(coins);
+}
+
+unsigned int CCoinsViewDBCursor::GetValueSize() const
+{
+ return pcursor->GetValueSize();
+}
+
+bool CCoinsViewDBCursor::Valid() const
+{
+ return keyTmp.first == DB_COINS;
+}
+
+void CCoinsViewDBCursor::Next()
+{
+ pcursor->Next();
+ if (pcursor->Valid()) {
+ bool ok = pcursor->GetKey(keyTmp);
+ assert(ok); // If GetKey fails here something must be wrong with underlying database, we cannot handle that here
+ } else {
+ keyTmp.first = 0; // Invalidate cached key after last record so that Valid() and GetKey() return false
}
- stats.hashSerialized = ss.GetHash();
- stats.nTotalAmount = nTotalAmount;
- return true;
}
bool CBlockTreeDB::WriteBatchSync(const std::vector<std::pair<int, const CBlockFileInfo*> >& fileInfo, int nLastFile, const std::vector<const CBlockIndex*>& blockinfo) {
diff --git a/src/txdb.h b/src/txdb.h
index 22e0c5704c..749802f0e5 100644
--- a/src/txdb.h
+++ b/src/txdb.h
@@ -26,6 +26,8 @@ static const int64_t nMaxDbCache = sizeof(void*) > 4 ? 16384 : 1024;
//! min. -dbcache in (MiB)
static const int64_t nMinDbCache = 4;
+class CCoinsViewDBCursor;
+
/** CCoinsView backed by the coin database (chainstate/) */
class CCoinsViewDB : public CCoinsView
{
@@ -38,7 +40,29 @@ public:
bool HaveCoins(const uint256 &txid) const;
uint256 GetBestBlock() const;
bool BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock);
- bool GetStats(CCoinsStats &stats) const;
+ CCoinsViewCursor *Cursor() const;
+};
+
+/** Specialization of CCoinsViewCursor to iterate over a CCoinsViewDB */
+class CCoinsViewDBCursor: public CCoinsViewCursor
+{
+public:
+ ~CCoinsViewDBCursor() {}
+
+ bool GetKey(uint256 &key) const;
+ bool GetValue(CCoins &coins) const;
+ unsigned int GetValueSize() const;
+
+ bool Valid() const;
+ void Next();
+
+private:
+ CCoinsViewDBCursor(CDBIterator* pcursorIn, const uint256 &hashBlockIn):
+ CCoinsViewCursor(hashBlockIn), pcursor(pcursorIn) {}
+ boost::scoped_ptr<CDBIterator> pcursor;
+ std::pair<char, uint256> keyTmp;
+
+ friend class CCoinsViewDB;
};
/** Access to the block database (blocks/index/) */
--
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