From 3f78562df5e86a2a0a21812047fc3a7db8cee988 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Sun, 30 Oct 2016 23:53:38 -0700
Subject: [PATCH] Add DumpMempool and LoadMempool

---
 src/init.cpp |   3 ++
 src/main.cpp | 113 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/main.h   |   6 +++
 3 files changed, 122 insertions(+)

diff --git a/src/init.cpp b/src/init.cpp
index 84b0108ea8..efaf821f4f 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -207,6 +207,7 @@ void Shutdown()
 
     StopTorControl();
     UnregisterNodeSignals(GetNodeSignals());
+    DumpMempool();
 
     if (fFeeEstimatesInitialized)
     {
@@ -659,6 +660,8 @@ void ThreadImport(std::vector<boost::filesystem::path> vImportFiles)
         LogPrintf("Stopping after block import\n");
         StartShutdown();
     }
+
+    LoadMempool();
 }
 
 /** Sanity checks
diff --git a/src/main.cpp b/src/main.cpp
index ccf7efcf0d..11abc0d175 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -6935,6 +6935,119 @@ int VersionBitsTipStateSinceHeight(const Consensus::Params& params, Consensus::D
     return VersionBitsStateSinceHeight(chainActive.Tip(), params, pos, versionbitscache);
 }
 
+static const uint64_t MEMPOOL_DUMP_VERSION = 1;
+
+bool LoadMempool(void)
+{
+    int64_t nExpiryTimeout = GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60;
+    FILE* filestr = fopen((GetDataDir() / "mempool.dat").string().c_str(), "r");
+    CAutoFile file(filestr, SER_DISK, CLIENT_VERSION);
+    if (file.IsNull()) {
+        LogPrintf("Failed to open mempool file from disk. Continuing anyway.\n");
+        return false;
+    }
+
+    int64_t count = 0;
+    int64_t skipped = 0;
+    int64_t failed = 0;
+    int64_t nNow = GetTime();
+
+    try {
+        uint64_t version;
+        file >> version;
+        if (version != MEMPOOL_DUMP_VERSION) {
+            return false;
+        }
+        uint64_t num;
+        file >> num;
+        double prioritydummy = 0;
+        while (num--) {
+            CTransaction tx;
+            int64_t nTime;
+            int64_t nFeeDelta;
+            file >> tx;
+            file >> nTime;
+            file >> nFeeDelta;
+
+            CAmount amountdelta = nFeeDelta;
+            if (amountdelta) {
+                mempool.PrioritiseTransaction(tx.GetHash(), tx.GetHash().ToString(), prioritydummy, amountdelta);
+            }
+            CValidationState state;
+            if (nTime + nExpiryTimeout > nNow) {
+                LOCK(cs_main);
+                AcceptToMemoryPoolWithTime(mempool, state, tx, true, NULL, nTime);
+                if (state.IsValid()) {
+                    ++count;
+                } else {
+                    ++failed;
+                }
+            } else {
+                ++skipped;
+            }
+        }
+        std::map<uint256, CAmount> mapDeltas;
+        file >> mapDeltas;
+
+        for (const auto& i : mapDeltas) {
+            mempool.PrioritiseTransaction(i.first, i.first.ToString(), prioritydummy, i.second);
+        }
+    } catch (const std::exception& e) {
+        LogPrintf("Failed to deserialize mempool data on disk: %s. Continuing anyway.\n", e.what());
+        return false;
+    }
+
+    LogPrintf("Imported mempool transactions from disk: %i successes, %i failed, %i expired\n", count, failed, skipped);
+    return true;
+}
+
+void DumpMempool(void)
+{
+    int64_t start = GetTimeMicros();
+
+    std::map<uint256, CAmount> mapDeltas;
+    std::vector<TxMempoolInfo> vinfo;
+
+    {
+        LOCK(mempool.cs);
+        for (const auto &i : mempool.mapDeltas) {
+            mapDeltas[i.first] = i.second.first;
+        }
+        vinfo = mempool.infoAll();
+    }
+
+    int64_t mid = GetTimeMicros();
+
+    try {
+        FILE* filestr = fopen((GetDataDir() / "mempool.dat.new").string().c_str(), "w");
+        if (!filestr) {
+            return;
+        }
+
+        CAutoFile file(filestr, SER_DISK, CLIENT_VERSION);
+
+        uint64_t version = MEMPOOL_DUMP_VERSION;
+        file << version;
+
+        file << (uint64_t)vinfo.size();
+        for (const auto& i : vinfo) {
+            file << *(i.tx);
+            file << (int64_t)i.nTime;
+            file << (int64_t)i.nFeeDelta;
+            mapDeltas.erase(i.tx->GetHash());
+        }
+
+        file << mapDeltas;
+        FileCommit(file.Get());
+        file.fclose();
+        RenameOver(GetDataDir() / "mempool.dat.new", GetDataDir() / "mempool.dat");
+        int64_t last = GetTimeMicros();
+        LogPrintf("Dumped mempool: %gs to copy, %gs to dump\n", (mid-start)*0.000001, (last-mid)*0.000001);
+    } catch (const std::exception& e) {
+        LogPrintf("Failed to dump mempool: %s. Continuing anyway.\n", e.what());
+    }
+}
+
 class CMainCleanup
 {
 public:
diff --git a/src/main.h b/src/main.h
index 5a3af52fed..4c6af95142 100644
--- a/src/main.h
+++ b/src/main.h
@@ -533,6 +533,12 @@ static const unsigned int REJECT_ALREADY_KNOWN = 0x101;
 /** Transaction conflicts with a transaction already known */
 static const unsigned int REJECT_CONFLICT = 0x102;
 
+/** Dump the mempool to disk. */
+void DumpMempool();
+
+/** Load the mempool from disk. */
+bool LoadMempool();
+
 // The following things handle network-processing logic
 // (and should be moved to a separate file)