From 9d5eb002ae5a2308acc1f5a6f2c37bec12fce06f Mon Sep 17 00:00:00 2001
From: xiphon <xiphon@protonmail.com>
Date: Wed, 4 Dec 2019 10:29:27 +0000
Subject: [PATCH] TransactionHistory: guard tx info list against concurrent
 access

---
 src/libwalletqt/TransactionHistory.cpp | 74 +++++++++++++++-----------
 src/libwalletqt/TransactionHistory.h   |  2 +
 2 files changed, 45 insertions(+), 31 deletions(-)

diff --git a/src/libwalletqt/TransactionHistory.cpp b/src/libwalletqt/TransactionHistory.cpp
index e6cfa44e..889bd7c4 100644
--- a/src/libwalletqt/TransactionHistory.cpp
+++ b/src/libwalletqt/TransactionHistory.cpp
@@ -32,10 +32,13 @@
 
 #include <QFile>
 #include <QDebug>
+#include <QReadLocker>
+#include <QWriteLocker>
 
 
 TransactionInfo *TransactionHistory::transaction(int index)
 {
+    QReadLocker locker(&m_tinfoLock);
 
     if (index < 0 || index >= m_tinfo.size()) {
         qCritical("%s: no transaction info for index %d", __FUNCTION__, index);
@@ -53,41 +56,48 @@ TransactionInfo *TransactionHistory::transaction(int index)
 
 QList<TransactionInfo *> TransactionHistory::getAll(quint32 accountIndex) const
 {
-    // XXX this invalidates previously saved history that might be used by model
-    emit refreshStarted();
-    qDeleteAll(m_tinfo);
-    m_tinfo.clear();
-
     QDateTime firstDateTime = QDateTime(QDate(2014, 4, 18)); // the genesis block
     QDateTime lastDateTime  = QDateTime::currentDateTime().addDays(1); // tomorrow (guard against jitter and timezones)
-    quint64 lastTxHeight = 0;
-    m_locked = false;
-    m_minutesToUnlock = 0;
-    TransactionHistory * parent = const_cast<TransactionHistory*>(this);
-    for (const auto i : m_pimpl->getAll()) {
-        TransactionInfo * ti = new TransactionInfo(i, parent);
-        if (ti->subaddrAccount() != accountIndex) {
-            delete ti;
-            continue;
-        }
-        m_tinfo.append(ti);
-        // looking for transactions timestamp scope
-        if (ti->timestamp() >= lastDateTime) {
-            lastDateTime = ti->timestamp();
-        }
-        if (ti->timestamp() <= firstDateTime) {
-            firstDateTime = ti->timestamp();
-        }
-        quint64 requiredConfirmations = (ti->blockHeight() < ti->unlockTime()) ? ti->unlockTime() - ti->blockHeight() : 10;
-        // store last tx height
-        if (ti->confirmations() < requiredConfirmations && ti->blockHeight() >= lastTxHeight) {
-            lastTxHeight = ti->blockHeight();
-            // TODO: Fetch block time and confirmations needed from wallet2?
-            m_minutesToUnlock = (requiredConfirmations - ti->confirmations()) * 2;
-            m_locked = true;
-        }
 
+    emit refreshStarted();
+
+    {
+        QWriteLocker locker(&m_tinfoLock);
+
+        // XXX this invalidates previously saved history that might be used by model
+        qDeleteAll(m_tinfo);
+        m_tinfo.clear();
+
+        quint64 lastTxHeight = 0;
+        m_locked = false;
+        m_minutesToUnlock = 0;
+        TransactionHistory * parent = const_cast<TransactionHistory*>(this);
+        for (const auto i : m_pimpl->getAll()) {
+            TransactionInfo * ti = new TransactionInfo(i, parent);
+            if (ti->subaddrAccount() != accountIndex) {
+                delete ti;
+                continue;
+            }
+            m_tinfo.append(ti);
+            // looking for transactions timestamp scope
+            if (ti->timestamp() >= lastDateTime) {
+                lastDateTime = ti->timestamp();
+            }
+            if (ti->timestamp() <= firstDateTime) {
+                firstDateTime = ti->timestamp();
+            }
+            quint64 requiredConfirmations = (ti->blockHeight() < ti->unlockTime()) ? ti->unlockTime() - ti->blockHeight() : 10;
+            // store last tx height
+            if (ti->confirmations() < requiredConfirmations && ti->blockHeight() >= lastTxHeight) {
+                lastTxHeight = ti->blockHeight();
+                // TODO: Fetch block time and confirmations needed from wallet2?
+                m_minutesToUnlock = (requiredConfirmations - ti->confirmations()) * 2;
+                m_locked = true;
+            }
+
+        }
     }
+
     emit refreshFinished();
 
     if (m_firstDateTime != firstDateTime) {
@@ -112,6 +122,8 @@ void TransactionHistory::refresh(quint32 accountIndex)
 
 quint64 TransactionHistory::count() const
 {
+    QReadLocker locker(&m_tinfoLock);
+
     return m_tinfo.count();
 }
 
diff --git a/src/libwalletqt/TransactionHistory.h b/src/libwalletqt/TransactionHistory.h
index ab494e1d..d28a0f6c 100644
--- a/src/libwalletqt/TransactionHistory.h
+++ b/src/libwalletqt/TransactionHistory.h
@@ -31,6 +31,7 @@
 
 #include <QObject>
 #include <QList>
+#include <QReadWriteLock>
 #include <QDateTime>
 
 namespace Monero {
@@ -76,6 +77,7 @@ private:
     friend class Wallet;
     Monero::TransactionHistory * m_pimpl;
     mutable QList<TransactionInfo*> m_tinfo;
+    mutable QReadWriteLock m_tinfoLock;
     mutable QDateTime   m_firstDateTime;
     mutable QDateTime   m_lastDateTime;
     mutable int m_minutesToUnlock;