GUI cold signing

main.cpp

@@ -40,6 +40,7 @@
 #include "Wallet.h"
 #include "QRCodeImageProvider.h"
 #include "PendingTransaction.h"
+#include "UnsignedTransaction.h"
 #include "TranslationManager.h"
 #include "TransactionInfo.h"
 #include "TransactionHistory.h"
@@ -72,6 +73,9 @@ int main(int argc, char *argv[])
     qmlRegisterUncreatableType<PendingTransaction>("moneroComponents.PendingTransaction", 1, 0, "PendingTransaction",
                                                    "PendingTransaction can't be instantiated directly");
 
+    qmlRegisterUncreatableType<UnsignedTransaction>("moneroComponents.UnsignedTransaction", 1, 0, "UnsignedTransaction",
+                                                   "UnsignedTransaction can't be instantiated directly");
+
     qmlRegisterUncreatableType<WalletManager>("moneroComponents.WalletManager", 1, 0, "WalletManager",
                                                    "WalletManager can't be instantiated directly");
 

main.qml

@@ -228,6 +228,8 @@ ApplicationWindow {
         currentWallet = wallet
         updateSyncing(false)
 
+        viewOnly = currentWallet.viewOnly;
+
         // connect handlers
         currentWallet.refreshed.connect(onWalletRefresh)
         currentWallet.updated.connect(onWalletUpdate)
@@ -293,7 +295,6 @@ ApplicationWindow {
 
         // wallet opened successfully, subscribing for wallet updates
         connectWallet(wallet)
-
     }
 
 
@@ -474,7 +475,7 @@ ApplicationWindow {
 
 
     // called on "transfer"
-    function handlePayment(address, paymentId, amount, mixinCount, priority, description) {
+    function handlePayment(address, paymentId, amount, mixinCount, priority, description, createFile) {
         console.log("Creating transaction: ")
         console.log("\taddress: ", address,
                     ", payment_id: ", paymentId,
@@ -522,6 +523,24 @@ ApplicationWindow {
             currentWallet.createTransactionAsync(address, paymentId, amountxmr, mixinCount, priority);
     }
 
+    //Choose where to save transaction
+    FileDialog {
+        id: saveTxDialog
+        title: "Please choose a location"
+        folder: "file://" +moneroAccountsDir
+        selectExisting: false;
+
+        onAccepted: {
+            handleTransactionConfirmed()
+        }
+        onRejected: {
+            // do nothing
+
+        }
+
+    }
+
+
     function handleSweepUnmixable() {
         console.log("Creating transaction: ")
 
@@ -562,7 +581,7 @@ ApplicationWindow {
     }
 
     // called after user confirms transaction
-    function handleTransactionConfirmed() {
+    function handleTransactionConfirmed(fileName) {
         // grab transaction.txid before commit, since it clears it.
         // we actually need to copy it, because QML will incredibly
         // call the function multiple times when the variable is used
@@ -573,6 +592,20 @@ ApplicationWindow {
         for (var i = 0; i < txid_org.length; ++i)
           txid[i] = txid_org[i]
 
+        // View only wallet - we save the tx
+        if(viewOnly && saveTxDialog.fileUrl){
+            // No file specified - abort
+            if(!saveTxDialog.fileUrl) {
+                currentWallet.disposeTransaction(transaction)
+                return;
+            }
+
+            var path = walletManager.urlToLocalPath(saveTxDialog.fileUrl)
+
+            // Store to file
+            transaction.setFilename(path);
+        }
+
         if (!transaction.commit()) {
             console.log("Error committing transaction: " + transaction.errorString);
             informationPopup.title = qsTr("Error") + translationManager.emptyString
@@ -585,7 +618,7 @@ ApplicationWindow {
                     txid_text += ", "
                 txid_text += txid[i]
             }
-            informationPopup.text  = qsTr("Money sent successfully: %1 transaction(s) ").arg(txid.length) + txid_text + translationManager.emptyString
+            informationPopup.text  = (viewOnly)? qsTr("Transaction saved to file: %1").arg(path) : qsTr("Money sent successfully: %1 transaction(s) ").arg(txid.length) + txid_text + translationManager.emptyString
             informationPopup.icon  = StandardIcon.Information
             if (transactionDescription.length > 0) {
                 for (var i = 0; i < txid.length; ++i)
@@ -771,10 +804,31 @@ ApplicationWindow {
         id: transactionConfirmationPopup
         onAccepted: {
             close();
-            handleTransactionConfirmed()
+
+            // Save transaction to file if view only wallet
+            if(viewOnly) {
+                saveTxDialog.open();
+                return;
+            } else
+                handleTransactionConfirmed()
+        }        
+    }
+
+    StandardDialog {
+        id: confirmationDialog
+        property var onAcceptedCallback
+        property var onRejectedCallback
+        onAccepted:  {
+            if (onAcceptedCallback)
+                onAcceptedCallback()
+        }
+        onRejected: {
+            if (onRejectedCallback)
+                onRejectedCallback();
         }
     }
 
+
     //Open Wallet from file
     FileDialog {
         id: fileDialog

monero-wallet-gui.pro

@@ -9,7 +9,7 @@ CONFIG += c++11
 # cleaning "auto-generated" bitmonero directory on "make distclean"
 QMAKE_DISTCLEAN += -r $$WALLET_ROOT
 
-INCLUDEPATH += $$WALLET_ROOT/include \
+INCLUDEPATH +=  $$WALLET_ROOT/include \
                 $$PWD/src/libwalletqt \
                 $$PWD/src/QR-Code-generator \
                 $$PWD/src \
@@ -36,7 +36,8 @@ HEADERS += \
     src/daemon/DaemonManager.h \
     src/model/AddressBookModel.h \
     src/libwalletqt/AddressBook.h \
-    src/zxcvbn-c/zxcvbn.h
+    src/zxcvbn-c/zxcvbn.h \
+    src/libwalletqt/UnsignedTransaction.h
 
 
 SOURCES += main.cpp \
@@ -59,7 +60,8 @@ SOURCES += main.cpp \
     src/daemon/DaemonManager.cpp \
     src/model/AddressBookModel.cpp \
     src/libwalletqt/AddressBook.cpp \
-    src/zxcvbn-c/zxcvbn.c
+    src/zxcvbn-c/zxcvbn.c \
+    src/libwalletqt/UnsignedTransaction.cpp
 
 lupdate_only {
 SOURCES = *.qml \
@@ -289,7 +291,8 @@ OTHER_FILES += \
     $$TRANSLATIONS
 
 DISTFILES += \
-    notes.txt
+    notes.txt \
+    monero/src/wallet/CMakeLists.txt
 
 
 # windows application icon

pages/Transfer.qml

@@ -92,7 +92,10 @@ Rectangle {
 
     Item {
       id: pageRoot
-      anchors.fill: parent
+      anchors.top: parent.top
+      anchors.left: parent.left
+      anchors.right: parent.right
+      height:550
     Label {
         id: amountLabel
         anchors.left: parent.left
@@ -381,7 +384,7 @@ Rectangle {
         shadowPressedColor: "#B32D00"
         releasedColor: "#FF6C3C"
         pressedColor: "#FF4304"
-        enabled : pageRoot.checkInformation(amountLine.text, addressLine.text, paymentIdLine.text, appWindow.persistentSettings.testnet)
+        enabled : !appWindow.viewOnly && pageRoot.checkInformation(amountLine.text, addressLine.text, paymentIdLine.text, appWindow.persistentSettings.testnet)
         onClicked: {
             console.log("Transfer: paymentClicked")
             var priority = priorityModel.get(priorityDropdown.currentIndex).priority
@@ -395,25 +398,7 @@ Rectangle {
         }
     }
 
-    StandardButton {
+    } // pageRoot
-        id: sweepUnmixableButton
-        anchors.right: parent.right
-        anchors.top: descriptionLine.bottom
-        anchors.rightMargin: 17
-        anchors.topMargin: 17
-        width: 60*2
-        text: qsTr("SWEEP UNMIXABLE") + translationManager.emptyString
-        shadowReleasedColor: "#FF4304"
-        shadowPressedColor: "#B32D00"
-        releasedColor: "#FF6C3C"
-        pressedColor: "#FF4304"
-        enabled : true
-        onClicked: {
-            console.log("Transfer: sweepUnmixableClicked")
-            root.sweepUnmixableClicked()
-
-        }
-    }
 
     Rectangle {
         id:desaturate
@@ -422,7 +407,192 @@ Rectangle {
         opacity: 0.1
         visible: (pageRoot.enabled)? 0 : 1;
     }
-    } // Rectangle
+
+    ColumnLayout {
+        anchors.top: pageRoot.bottom
+        anchors.left: parent.left
+        anchors.right: parent.right
+        anchors.margins: 17
+        spacing:10
+        enabled: !viewOnly || pageRoot.enabled
+
+        RowLayout {
+            Label {
+                id: manageWalletLabel
+                Layout.fillWidth: true
+                color: "#4A4949"
+                text: qsTr("Advanced") + translationManager.emptyString
+                fontSize: 16
+                Layout.topMargin: 20
+            }
+        }
+
+        Rectangle {
+            Layout.fillWidth: true
+            height: 1
+            color: "#DEDEDE"
+        }
+
+        RowLayout {
+            StandardButton {
+                id: sweepUnmixableButton
+                text: qsTr("SWEEP UNMIXABLE") + translationManager.emptyString
+                shadowReleasedColor: "#FF4304"
+                shadowPressedColor: "#B32D00"
+                releasedColor: "#FF6C3C"
+                pressedColor: "#FF4304"
+                enabled : pageRoot.enabled
+                onClicked: {
+                    console.log("Transfer: sweepUnmixableClicked")
+                    root.sweepUnmixableClicked()
+                }
+            }
+
+            StandardButton {
+                id: saveTxButton
+                text: qsTr("create tx file") + translationManager.emptyString
+                shadowReleasedColor: "#FF4304"
+                shadowPressedColor: "#B32D00"
+                releasedColor: "#FF6C3C"
+                pressedColor: "#FF4304"
+                visible: appWindow.viewOnly
+                enabled: pageRoot.checkInformation(amountLine.text, addressLine.text, paymentIdLine.text, appWindow.persistentSettings.testnet)
+                onClicked: {
+                    console.log("Transfer: saveTx Clicked")
+                    var priority = priorityModel.get(priorityDropdown.currentIndex).priority
+                    console.log("priority: " + priority)
+                    console.log("amount: " + amountLine.text)
+                    addressLine.text = addressLine.text.trim()
+                    paymentIdLine.text = paymentIdLine.text.trim()
+                    root.paymentClicked(addressLine.text, paymentIdLine.text, amountLine.text, scaleValueToMixinCount(privacyLevelItem.fillLevel),
+                                   priority, descriptionLine.text)
+
+                }
+            }
+
+            StandardButton {
+                id: signTxButton
+                text: qsTr("sign tx file") + translationManager.emptyString
+                shadowReleasedColor: "#FF4304"
+                shadowPressedColor: "#B32D00"
+                releasedColor: "#FF6C3C"
+                pressedColor: "#FF4304"
+                visible: !appWindow.viewOnly
+                onClicked: {
+                    console.log("Transfer: sign tx clicked")
+                    signTxDialog.open();
+                }
+            }
+
+            StandardButton {
+                id: submitTxButton
+                text: qsTr("submit tx file") + translationManager.emptyString
+                shadowReleasedColor: "#FF4304"
+                shadowPressedColor: "#B32D00"
+                releasedColor: "#FF6C3C"
+                pressedColor: "#FF4304"
+                visible: appWindow.viewOnly
+                enabled: pageRoot.enabled
+                onClicked: {
+                    console.log("Transfer: submit tx clicked")
+                    submitTxDialog.open();
+                }
+            }
+        }
+
+
+    }
+
+
+
+    //SignTxDialog
+    FileDialog {
+        id: signTxDialog
+        title: "Please choose a file"
+        folder: "file://" +moneroAccountsDir
+        nameFilters: [ "Unsigned transfers (*)"]
+
+        onAccepted: {
+            var path = walletManager.urlToLocalPath(fileUrl);
+            // Load the unsigned tx from file
+            var transaction = currentWallet.loadTxFile(path);
+
+            if (transaction.status !== PendingTransaction.Status_Ok) {
+                console.error("Can't load unsigned transaction: ", transaction.errorString);
+                informationPopup.title = qsTr("Error") + translationManager.emptyString;
+                informationPopup.text  = qsTr("Can't load unsigned transaction: ") + transaction.errorString
+                informationPopup.icon  = StandardIcon.Critical
+                informationPopup.onCloseCallback = null
+                informationPopup.open();
+                // deleting transaction object, we don't want memleaks
+                transaction.destroy();
+            } else {
+                    confirmationDialog.text =  qsTr("\nNumber of transactions: ") + transaction.txCount
+                for (var i = 0; i < transaction.txCount; ++i) {
+                    confirmationDialog.text += qsTr("\nTransaction #%1").arg(i+1)
+                    +qsTr("\nRecipient: ") + transaction.recipientAddress[i]
+                    + (transaction.paymentId[i] == "" ? "" : qsTr("\n\payment ID: ") + transaction.paymentId[i])
+                    + qsTr("\nAmount: ") + walletManager.displayAmount(transaction.amount(i))
+                    + qsTr("\nFee: ") + walletManager.displayAmount(transaction.fee(i))
+                    + qsTr("\nMixin: ") + transaction.mixin(i)
+
+                    // TODO: add descriptions to unsigned_tx_set?
+    //              + (transactionDescription === "" ? "" : (qsTr("\n\nDescription: ") + transactionDescription))
+                    + translationManager.emptyString
+                    if (i > 0) {
+                        confirmationDialog.text += "\n\n"
+                    }
+
+                }
+
+                console.log(transaction.confirmationMessage);
+
+                // Show confirmation dialog
+                confirmationDialog.title = qsTr("Confirmation") + translationManager.emptyString
+                confirmationDialog.icon = StandardIcon.Question
+                confirmationDialog.onAcceptedCallback = function() {
+                    transaction.sign(path+"_signed");
+                    transaction.destroy();
+                };
+                confirmationDialog.onRejectedCallback = transaction.destroy;
+
+                confirmationDialog.open()
+            }
+
+        }
+        onRejected: {
+            // File dialog closed
+            console.log("Canceled")
+        }
+    }
+
+    //SignTxDialog
+    FileDialog {
+        id: submitTxDialog
+        title: "Please choose a file"
+        folder: "file://" +moneroAccountsDir
+        nameFilters: [ "signed transfers (*)"]
+
+        onAccepted: {
+            if(!currentWallet.submitTxFile(walletManager.urlToLocalPath(fileUrl))){
+                informationPopup.title = qsTr("Error") + translationManager.emptyString;
+                informationPopup.text  = qsTr("Can't submit transaction: ") + currentWallet.errorString
+                informationPopup.icon  = StandardIcon.Critical
+                informationPopup.onCloseCallback = null
+                informationPopup.open();
+            } else {
+                informationPopup.title = qsTr("Information") + translationManager.emptyString
+                informationPopup.text  = qsTr("Money sent successfully") + translationManager.emptyString
+                informationPopup.icon  = StandardIcon.Information
+                informationPopup.onCloseCallback = null
+                informationPopup.open();
+            }
+        }
+        onRejected: {
+            console.log("Canceled")
+        }
+
+    }
 
     Rectangle {
         x: root.width/2 - width/2
@@ -465,9 +635,10 @@ Rectangle {
         }
 
         if (currentWallet.viewOnly) {
-            statusText.text = qsTr("Wallet is view only.")
+           // statusText.text = qsTr("Wallet is view only.")
-            return;
+           //return;
         }
+        pageRoot.enabled = false;
 
         switch (currentWallet.connected) {
         case Wallet.ConnectionStatus_Disconnected:

src/libwalletqt/PendingTransaction.cpp

@@ -13,7 +13,10 @@ QString PendingTransaction::errorString() const
 
 bool PendingTransaction::commit()
 {
-    return m_pimpl->commit();
+    // Save transaction to file if fileName is set.
+    if(!m_fileName.isEmpty())
+        return m_pimpl->commit(m_fileName.toStdString());
+    return m_pimpl->commit(m_fileName.toStdString());
 }
 
 quint64 PendingTransaction::amount() const
@@ -47,6 +50,11 @@ quint64 PendingTransaction::txCount() const
     return m_pimpl->txCount();
 }
 
+void PendingTransaction::setFilename(const QString &fileName)
+{
+    m_fileName = fileName;
+}
+
 PendingTransaction::PendingTransaction(Monero::PendingTransaction *pt, QObject *parent)
     : QObject(parent), m_pimpl(pt)
 {

src/libwalletqt/PendingTransaction.h

@@ -44,6 +44,7 @@ public:
     quint64 fee() const;
     QStringList txid() const;
     quint64 txCount() const;
+    Q_INVOKABLE void setFilename(const QString &fileName);
 
 private:
     explicit PendingTransaction(Monero::PendingTransaction * pt, QObject *parent = 0);
@@ -51,6 +52,7 @@ private:
 private:
     friend class Wallet;
     Monero::PendingTransaction * m_pimpl;
+    QString m_fileName;
 };
 
 #endif // PENDINGTRANSACTION_H

src/libwalletqt/UnsignedTransaction.cpp

@@ -0,0 +1,89 @@
+#include "UnsignedTransaction.h"
+#include <QVector>
+#include <QDebug>
+
+UnsignedTransaction::Status UnsignedTransaction::status() const
+{
+    return static_cast<Status>(m_pimpl->status());
+}
+
+QString UnsignedTransaction::errorString() const
+{
+    return QString::fromStdString(m_pimpl->errorString());
+}
+
+quint64 UnsignedTransaction::amount(int index) const
+{
+    std::vector<uint64_t> arr = m_pimpl->amount();
+    if(index > arr.size() - 1)
+        return 0;
+    return arr[index];
+}
+
+quint64 UnsignedTransaction::fee(int index) const
+{
+    std::vector<uint64_t> arr = m_pimpl->fee();
+    if(index > arr.size() - 1)
+        return 0;
+    return arr[index];
+}
+
+quint64 UnsignedTransaction::mixin(int index) const
+{
+    std::vector<uint64_t> arr = m_pimpl->mixin();
+    if(index > arr.size() - 1)
+        return 0;
+    return arr[index];
+}
+
+quint64 UnsignedTransaction::txCount() const
+{
+    return m_pimpl->txCount();
+}
+
+quint64 UnsignedTransaction::minMixinCount() const
+{
+    return m_pimpl->minMixinCount();
+}
+
+QString UnsignedTransaction::confirmationMessage() const
+{
+    return QString::fromStdString(m_pimpl->confirmationMessage());
+}
+
+QStringList UnsignedTransaction::paymentId() const
+{
+    QList<QString> list;
+    for (const auto &t: m_pimpl->paymentId())
+        list.append(QString::fromStdString(t));
+    return list;
+}
+
+QStringList UnsignedTransaction::recipientAddress() const
+{
+    QList<QString> list;
+    for (const auto &t: m_pimpl->recipientAddress())
+        list.append(QString::fromStdString(t));
+    return list;
+}
+
+bool UnsignedTransaction::sign(const QString &fileName) const
+{
+    return m_pimpl->sign(fileName.toStdString());
+}
+
+void UnsignedTransaction::setFilename(const QString &fileName)
+{
+    m_fileName = fileName;
+}
+
+UnsignedTransaction::UnsignedTransaction(Monero::UnsignedTransaction *pt, QObject *parent)
+    : QObject(parent), m_pimpl(pt)
+{
+
+}
+
+UnsignedTransaction::~UnsignedTransaction()
+{
+    delete m_pimpl;
+}

src/libwalletqt/UnsignedTransaction.h

@@ -0,0 +1,58 @@
+#ifndef UNSIGNEDTRANSACTION_H
+#define UNSIGNEDTRANSACTION_H
+
+#include <QObject>
+
+#include <wallet/wallet2_api.h>
+
+class UnsignedTransaction : public QObject
+{
+    Q_OBJECT
+    Q_PROPERTY(Status status READ status)
+    Q_PROPERTY(QString errorString READ errorString)
+  //  Q_PROPERTY(QList<qulonglong> amount READ amount)
+  //  Q_PROPERTY(QList<qulonglong> fee READ fee)
+    Q_PROPERTY(quint64 txCount READ txCount)
+    Q_PROPERTY(QString confirmationMessage READ confirmationMessage)
+    Q_PROPERTY(QStringList recipientAddress READ recipientAddress)
+    Q_PROPERTY(QStringList paymentId READ paymentId)
+    Q_PROPERTY(quint64 minMixinCount READ minMixinCount)
+
+public:
+    enum Status {
+        Status_Ok       = Monero::UnsignedTransaction::Status_Ok,
+        Status_Error    = Monero::UnsignedTransaction::Status_Error,
+        Status_Critical    = Monero::UnsignedTransaction::Status_Critical
+    };
+    Q_ENUM(Status)
+
+    enum Priority {
+        Priority_Low    = Monero::UnsignedTransaction::Priority_Low,
+        Priority_Medium = Monero::UnsignedTransaction::Priority_Medium,
+        Priority_High   = Monero::UnsignedTransaction::Priority_High
+    };
+    Q_ENUM(Priority)
+
+    Status status() const;
+    QString errorString() const;
+    Q_INVOKABLE quint64 amount(int index) const;
+    Q_INVOKABLE quint64 fee(int index) const;
+    Q_INVOKABLE quint64 mixin(int index) const;
+    QStringList recipientAddress() const;
+    QStringList paymentId() const;
+    quint64 txCount() const;
+    QString confirmationMessage() const;
+    quint64 minMixinCount() const;
+    Q_INVOKABLE bool sign(const QString &fileName) const;
+    Q_INVOKABLE void setFilename(const QString &fileName);
+
+private:
+    explicit UnsignedTransaction(Monero::UnsignedTransaction * pt, QObject *parent = 0);
+    ~UnsignedTransaction();
+private:
+    friend class Wallet;
+    Monero::UnsignedTransaction * m_pimpl;
+    QString m_fileName;
+};
+
+#endif // UNSIGNEDTRANSACTION_H

src/libwalletqt/Wallet.cpp

@@ -1,5 +1,6 @@
 #include "Wallet.h"
 #include "PendingTransaction.h"
+#include "UnsignedTransaction.h"
 #include "TransactionHistory.h"
 #include "AddressBook.h"
 #include "model/TransactionHistoryModel.h"
@@ -211,7 +212,6 @@ quint64 Wallet::daemonBlockChainHeight() const
 
 quint64 Wallet::daemonBlockChainTargetHeight() const
 {
-
     if (m_daemonBlockChainTargetHeight == 0
             || m_daemonBlockChainTargetHeightTime.elapsed() / 1000 > m_daemonBlockChainTargetHeightTtl) {
         m_daemonBlockChainTargetHeight = m_walletImpl->daemonBlockChainTargetHeight();
@@ -323,12 +323,31 @@ void Wallet::createSweepUnmixableTransactionAsync()
     });
 }
 
+UnsignedTransaction * Wallet::loadTxFile(const QString &fileName)
+{
+    qDebug() << "Trying to sign " << fileName;
+    Monero::UnsignedTransaction * ptImpl = m_walletImpl->loadUnsignedTx(fileName.toStdString());
+    UnsignedTransaction * result = new UnsignedTransaction(ptImpl, this);
+    return result;
+}
+
+bool Wallet::submitTxFile(const QString &fileName) const
+{
+    qDebug() << "Trying to submit " << fileName;
+    return m_walletImpl->submitTransaction(fileName.toStdString());
+}
+
 void Wallet::disposeTransaction(PendingTransaction *t)
 {
     m_walletImpl->disposeTransaction(t->m_pimpl);
     delete t;
 }
 
+void Wallet::disposeTransaction(UnsignedTransaction *t)
+{
+    delete t;
+}
+
 TransactionHistory *Wallet::history() const
 {
     return m_history;

src/libwalletqt/Wallet.h

@@ -6,6 +6,7 @@
 
 #include "wallet/wallet2_api.h" // we need to have an access to the Monero::Wallet::Status enum here;
 #include "PendingTransaction.h" // we need to have an access to the PendingTransaction::Priority enum here;
+#include "UnsignedTransaction.h"
 
 namespace Monero {
     class Wallet; // forward declaration
@@ -162,9 +163,19 @@ public:
     //! creates async sweep unmixable transaction
     Q_INVOKABLE void createSweepUnmixableTransactionAsync();
 
+    //! Sign a transfer from file
+    Q_INVOKABLE UnsignedTransaction * loadTxFile(const QString &fileName);
+
+    //! Submit a transfer from file
+    Q_INVOKABLE bool submitTxFile(const QString &fileName) const;
+
+
     //! deletes transaction and frees memory
     Q_INVOKABLE void disposeTransaction(PendingTransaction * t);
 
+    //! deletes unsigned transaction and frees memory
+    Q_INVOKABLE void disposeTransaction(UnsignedTransaction * t);
+
     //! returns transaction history
     TransactionHistory * history() const;