Start to persist zindex stats to disk

src/main.cpp

@@ -572,6 +572,96 @@ namespace {
 
 } // anon namespace
 
+// CZindexDB
+CZindexDB::CZindexDB()
+{
+    pathAddr = GetDataDir() / "zindex.dat";
+}
+
+bool CZindexDB::Read(CZindexStats& zstats)
+{
+    // open input file, and associate with CAutoFile
+    FILE *file = fopen(pathAddr.string().c_str(), "rb");
+    CAutoFile filein(file, SER_DISK, CLIENT_VERSION);
+    if (filein.IsNull())
+        return error("%s: Failed to open file %s", __func__, pathAddr.string());
+
+    // use file size to size memory buffer
+    int fileSize = boost::filesystem::file_size(pathAddr);
+    int dataSize = fileSize - sizeof(uint256);
+    // Don't try to resize to a negative number if file is small
+    if (dataSize < 0)
+        dataSize = 0;
+    vector<unsigned char> vchData;
+    vchData.resize(dataSize);
+    uint256 hashIn;
+
+    // read data and checksum from file
+    try {
+        filein.read((char *)&vchData[0], dataSize);
+        filein >> hashIn;
+    }
+    catch (const std::exception& e) {
+        return error("%s: Deserialize or I/O error - %s", __func__, e.what());
+    }
+    filein.fclose();
+
+    CDataStream ssZstats(vchData, SER_DISK, CLIENT_VERSION);
+
+    // verify stored checksum matches input data
+    uint256 hashTmp = Hash(ssPeers.begin(), ssPeers.end());
+    if (hashIn != hashTmp)
+        return error("%s: Checksum mismatch, data corrupted", __func__);
+
+    unsigned char pchMsgTmp[4];
+    try {
+        // de-serialize file header (network specific magic number) and ..
+        ssZstats >> FLATDATA(pchMsgTmp);
+
+        // ... verify the network matches ours
+        if (memcmp(pchMsgTmp, Params().MessageStart(), sizeof(pchMsgTmp)))
+            return error("%s: Invalid network magic number", __func__);
+
+        // de-serialize address data into one CAddrMan object
+        ssZstats >> addr;
+    }
+    catch (const std::exception& e) {
+        return error("%s: Deserialize or I/O error - %s", __func__, e.what());
+    }
+
+    return true;
+}
+
+bool CZindexDB::Write(const CZindexStats& zstats)
+{
+    // Generate random temporary filename
+    unsigned short randv = 0;
+    GetRandBytes((unsigned char*)&randv, sizeof(randv));
+    std::string tmpfn = strprintf("zindex.dat.%04x", randv);
+
+    // serialize zstats, checksum data up to that point, then append checksum
+    CDataStream ssZstats(SER_DISK, CLIENT_VERSION);
+    ssZstats << FLATDATA(Params().MessageStart());
+    ssZstats << zstats;
+    uint256 hash = Hash(ssZstats.begin(), ssZstats.end());
+    ssZstats << hash;
+
+    // Write and commit header, data
+    try {
+        fileout << ssPeers;
+    } catch (const std::exception& e) {
+        return error("%s: Serialize or I/O error - %s", __func__, e.what());
+    }
+    FileCommit(fileout.Get());
+    fileout.fclose();
+
+    // replace existing zindex.dat, if any, with new zindex.dat.XXXX
+    if (!RenameOver(pathTmp, pathAddr))
+        return error("%s: Rename-into-place failed", __func__);
+
+    return true;
+}
+
 bool GetNodeStateStats(NodeId nodeid, CNodeStateStats &stats) {
     LOCK(cs_main);
     CNodeState *state = State(nodeid);
@@ -4603,6 +4693,8 @@ bool ReceivedBlockTransactions(const CBlock &block, CValidationState& state, CBl
         }
     }
 
+    // TODO: Update zindex.dat on disk
+
     if (fZindex)
         fprintf(stderr, "ht.%d, ShieldedPayments=%d, ShieldedTx=%d, ShieldedOutputs=%d, FullyShieldedTx=%d, ntz=%d\n",
         pindexNew->GetHeight(), nShieldedPayments, nShieldedTx, nShieldedOutputs, nFullyShieldedTx, nNotarizations );