Refactor leveldbwrapper

Was "Add chainstate obfuscation to avoid spurious antivirus detection"

Zcash: Extracted the refactor, omitting the chainstate obfuscation.

src/Makefile.test.include

@@ -60,6 +60,7 @@ BITCOIN_TESTS =\
   test/getarg_tests.cpp \
   test/hash_tests.cpp \
   test/key_tests.cpp \
+  test/leveldbwrapper_tests.cpp \
   test/main_tests.cpp \
   test/mempool_tests.cpp \
   test/miner_tests.cpp \

src/leveldbwrapper.cpp

@@ -12,6 +12,7 @@
 #include <leveldb/env.h>
 #include <leveldb/filter_policy.h>
 #include <memenv.h>
+#include <stdint.h>
 
 void HandleError(const leveldb::Status& status)
 {
@@ -87,3 +88,10 @@ bool CLevelDBWrapper::WriteBatch(CLevelDBBatch& batch, bool fSync)
     HandleError(status);
     return true;
 }
+
+bool CLevelDBWrapper::IsEmpty()
+{
+    boost::scoped_ptr<leveldb::Iterator> it(NewIterator());
+    it->SeekToFirst();
+    return !(it->Valid());
+}

src/leveldbwrapper.h

@@ -86,6 +86,12 @@ private:
     leveldb::DB* pdb;
 
 public:
+    /**
+     * @param[in] path        Location in the filesystem where leveldb data will be stored.
+     * @param[in] nCacheSize  Configures various leveldb cache settings.
+     * @param[in] fMemory     If true, use leveldb's memory environment.
+     * @param[in] fWipe       If true, remove all existing data.
+     */
     CLevelDBWrapper(const boost::filesystem::path& path, size_t nCacheSize, bool fMemory = false, bool fWipe = false);
     ~CLevelDBWrapper();
 
@@ -168,6 +174,13 @@ public:
     {
         return pdb->NewIterator(iteroptions);
     }
+
+    /**
+     * Return true if the database managed by this class contains no entries.
+     */
+    bool IsEmpty();
+
 };
 
 #endif // BITCOIN_LEVELDBWRAPPER_H
+

src/test/leveldbwrapper_tests.cpp

@@ -0,0 +1,45 @@
+// Copyright (c) 2012-2013 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "leveldbwrapper.h"
+#include "uint256.h"
+#include "random.h"
+#include "test/test_bitcoin.h"
+
+#include <boost/assign/std/vector.hpp> // for 'operator+=()'
+#include <boost/assert.hpp>
+#include <boost/test/unit_test.hpp>
+                    
+using namespace std;
+using namespace boost::assign; // bring 'operator+=()' into scope
+using namespace boost::filesystem;
+         
+// Test if a string consists entirely of null characters
+bool is_null_key(const vector<unsigned char>& key) {
+    bool isnull = true;
+
+    for (unsigned int i = 0; i < key.size(); i++)
+        isnull &= (key[i] == '\x00');
+
+    return isnull;
+}
+ 
+BOOST_FIXTURE_TEST_SUITE(leveldbwrapper_tests, BasicTestingSetup)
+                       
+BOOST_AUTO_TEST_CASE(leveldbwrapper)
+{
+    {
+        path ph = temp_directory_path() / unique_path();
+        CLevelDBWrapper dbw(ph, (1 << 20), true, false);
+        char key = 'k';
+        uint256 in = GetRandHash();
+        uint256 res;
+
+        BOOST_CHECK(dbw.Write(key, in));
+        BOOST_CHECK(dbw.Read(key, res));
+        BOOST_CHECK_EQUAL(res.ToString(), in.ToString());
+    }
+}
+ 
+BOOST_AUTO_TEST_SUITE_END()

src/txdb.cpp

@@ -50,17 +50,6 @@ void static BatchWriteNullifier(CLevelDBBatch &batch, const uint256 &nf, const b
         batch.Write(make_pair(DB_NULLIFIER, nf), true);
 }
 
-void static BatchWriteCoins(CLevelDBBatch &batch, const uint256 &hash, const CCoins &coins) {
-    if (coins.IsPruned())
-        batch.Erase(make_pair(DB_COINS, hash));
-    else
-        batch.Write(make_pair(DB_COINS, hash), coins);
-}
-
-void static BatchWriteHashBestChain(CLevelDBBatch &batch, const uint256 &hash) {
-    batch.Write(DB_BEST_BLOCK, hash);
-}
-
 void static BatchWriteHashBestAnchor(CLevelDBBatch &batch, const uint256 &hash) {
     batch.Write(DB_BEST_ANCHOR, hash);
 }
@@ -68,7 +57,8 @@ void static BatchWriteHashBestAnchor(CLevelDBBatch &batch, const uint256 &hash)
 CCoinsViewDB::CCoinsViewDB(std::string dbName, size_t nCacheSize, bool fMemory, bool fWipe) : db(GetDataDir() / dbName, nCacheSize, fMemory, fWipe) {
 }
 
-CCoinsViewDB::CCoinsViewDB(size_t nCacheSize, bool fMemory, bool fWipe) : db(GetDataDir() / "chainstate", nCacheSize, fMemory, fWipe) {
+CCoinsViewDB::CCoinsViewDB(size_t nCacheSize, bool fMemory, bool fWipe) : db(GetDataDir() / "chainstate", nCacheSize, fMemory, fWipe) 
+{
 }
 
 
@@ -123,7 +113,10 @@ bool CCoinsViewDB::BatchWrite(CCoinsMap &mapCoins,
     size_t changed = 0;
     for (CCoinsMap::iterator it = mapCoins.begin(); it != mapCoins.end();) {
         if (it->second.flags & CCoinsCacheEntry::DIRTY) {
-            BatchWriteCoins(batch, it->first, it->second.coins);
+            if (it->second.coins.IsPruned())
+                batch.Erase(make_pair(DB_COINS, it->first));
+            else
+                batch.Write(make_pair(DB_COINS, it->first), it->second.coins);
             changed++;
         }
         count++;
@@ -150,7 +143,7 @@ bool CCoinsViewDB::BatchWrite(CCoinsMap &mapCoins,
     }
 
     if (!hashBlock.IsNull())
-        BatchWriteHashBestChain(batch, hashBlock);
+        batch.Write(DB_BEST_BLOCK, hashBlock);
     if (!hashAnchor.IsNull())
         BatchWriteHashBestAnchor(batch, hashAnchor);