Bitcoin-Qt: fix known addressbook bugs

- add qSort() for cachedAddressTable, as qLowerBound() and qUpperBound()
  require the list to be in ascending order (see
  http://harmattan-dev.nokia.com/docs/library/html/qt4/qtalgorithms.html#qLowerBound)
- add a new check in AddressTableModel::setData() to just return, when no
  changes were made to a label or an address (prevents entry duplication
  issue)
- remove "rec->label = value.toString();" from
  AddressTableModel::setData() as the label gets updated by
  AddressTablePriv::updateEntry() anyway (seems @sipa added this line via
  https://github.com/bitcoin/bitcoin/commit/1025440184ef100a22d07c7bb543ee45cf169d64#L6R225)
- add another new check in AddressTableModel::setData() to just return, if
  a duplicate address was found (prevents address overwrite)
- add a new check to EditAddressDialog::setModel() to prevent setting an
  invalid model
- re-work the switch-case statement in AddressTableModel::accept() to
  always break (as return get's called anyway) and order the list to match
  the enum definition
- make accept() in editaddressdialog.h a public slot, which it should be
- misc small coding style changes

4 files changed, 64 insertions, 33 deletions

diff --git a/src/qt/addresstablemodel.cpp b/src/qt/addresstablemodel.cpp
index e65d3915ec..03b09cdceb 100644
--- a/src/qt/addresstablemodel.cpp
+++ b/src/qt/addresstablemodel.cpp
@@ -69,6 +69,8 @@ public:
                                   QString::fromStdString(address.ToString())));
             }
         }
+        // qLowerBound() and qUpperBound() require our cachedAddressTable list to be sorted in asc order
+        qSort(cachedAddressTable.begin(), cachedAddressTable.end(), AddressTableEntryLessThan());
     }
 
     void updateEntry(const QString &address, const QString &label, bool isMine, int status)
@@ -208,7 +210,7 @@ QVariant AddressTableModel::data(const QModelIndex &index, int role) const
     return QVariant();
 }
 
-bool AddressTableModel::setData(const QModelIndex & index, const QVariant & value, int role)
+bool AddressTableModel::setData(const QModelIndex &index, const QVariant &value, int role)
 {
     if(!index.isValid())
         return false;
@@ -221,18 +223,36 @@ bool AddressTableModel::setData(const QModelIndex & index, const QVariant & valu
         switch(index.column())
         {
         case Label:
+            // Do nothing, if old label == new label
+            if(rec->label == value.toString())
+            {
+                editStatus = NO_CHANGES;
+                return false;
+            }
             wallet->SetAddressBookName(CBitcoinAddress(rec->address.toStdString()).Get(), value.toString().toStdString());
-            rec->label = value.toString();
             break;
         case Address:
+            // Do nothing, if old address == new address
+            if(CBitcoinAddress(rec->address.toStdString()) == CBitcoinAddress(value.toString().toStdString()))
+            {
+                editStatus = NO_CHANGES;
+                return false;
+            }
             // Refuse to set invalid address, set error status and return false
-            if(!walletModel->validateAddress(value.toString()))
+            else if(!walletModel->validateAddress(value.toString()))
             {
                 editStatus = INVALID_ADDRESS;
                 return false;
             }
+            // Check for duplicate addresses to prevent accidental deletion of addresses, if you try
+            // to paste an existing address over another address (with a different label)
+            else if(wallet->mapAddressBook.count(CBitcoinAddress(value.toString().toStdString()).Get()))
+            {
+                editStatus = DUPLICATE_ADDRESS;
+                return false;
+            }
             // Double-check that we're not overwriting a receiving address
-            if(rec->type == AddressTableEntry::Sending)
+            else if(rec->type == AddressTableEntry::Sending)
             {
                 {
                     LOCK(wallet->cs_wallet);
@@ -244,7 +264,6 @@ bool AddressTableModel::setData(const QModelIndex & index, const QVariant & valu
             }
             break;
         }
-
         return true;
     }
     return false;
@@ -262,7 +281,7 @@ QVariant AddressTableModel::headerData(int section, Qt::Orientation orientation,
     return QVariant();
 }
 
-Qt::ItemFlags AddressTableModel::flags(const QModelIndex & index) const
+Qt::ItemFlags AddressTableModel::flags(const QModelIndex &index) const
 {
     if(!index.isValid())
         return 0;
@@ -279,7 +298,7 @@ Qt::ItemFlags AddressTableModel::flags(const QModelIndex & index) const
     return retval;
 }
 
-QModelIndex AddressTableModel::index(int row, int column, const QModelIndex & parent) const
+QModelIndex AddressTableModel::index(int row, int column, const QModelIndex &parent) const
 {
     Q_UNUSED(parent);
     AddressTableEntry *data = priv->index(row);
@@ -345,6 +364,7 @@ QString AddressTableModel::addRow(const QString &type, const QString &label, con
     {
         return QString();
     }
+
     // Add entry
     {
         LOCK(wallet->cs_wallet);
@@ -353,7 +373,7 @@ QString AddressTableModel::addRow(const QString &type, const QString &label, con
     return QString::fromStdString(strAddress);
 }
 
-bool AddressTableModel::removeRows(int row, int count, const QModelIndex & parent)
+bool AddressTableModel::removeRows(int row, int count, const QModelIndex &parent)
 {
     Q_UNUSED(parent);
     AddressTableEntry *rec = priv->index(row);
diff --git a/src/qt/addresstablemodel.h b/src/qt/addresstablemodel.h
index 42974e3e1f..ae3e3b2f04 100644
--- a/src/qt/addresstablemodel.h
+++ b/src/qt/addresstablemodel.h
@@ -29,26 +29,27 @@ public:
 
     /** Return status of edit/insert operation */
     enum EditStatus {
-        OK,
-        INVALID_ADDRESS,   /**< Unparseable address */
-        DUPLICATE_ADDRESS,  /**< Address already in address book */
-        WALLET_UNLOCK_FAILURE, /**< Wallet could not be unlocked to create new receiving address */
-        KEY_GENERATION_FAILURE /**< Generating a new public key for a receiving address failed */
+        OK,                     /**< Everything ok */
+        NO_CHANGES,             /**< No changes were made during edit operation */
+        INVALID_ADDRESS,        /**< Unparseable address */
+        DUPLICATE_ADDRESS,      /**< Address already in address book */
+        WALLET_UNLOCK_FAILURE,  /**< Wallet could not be unlocked to create new receiving address */
+        KEY_GENERATION_FAILURE  /**< Generating a new public key for a receiving address failed */
     };
 
-    static const QString Send; /**< Specifies send address */
-    static const QString Receive; /**< Specifies receive address */
+    static const QString Send;      /**< Specifies send address */
+    static const QString Receive;   /**< Specifies receive address */
 
     /** @name Methods overridden from QAbstractTableModel
         @{*/
     int rowCount(const QModelIndex &parent) const;
     int columnCount(const QModelIndex &parent) const;
     QVariant data(const QModelIndex &index, int role) const;
-    bool setData(const QModelIndex & index, const QVariant & value, int role);
+    bool setData(const QModelIndex &index, const QVariant &value, int role);
     QVariant headerData(int section, Qt::Orientation orientation, int role) const;
-    QModelIndex index(int row, int column, const QModelIndex & parent) const;
-    bool removeRows(int row, int count, const QModelIndex & parent = QModelIndex());
-    Qt::ItemFlags flags(const QModelIndex & index) const;
+    QModelIndex index(int row, int column, const QModelIndex &parent) const;
+    bool removeRows(int row, int count, const QModelIndex &parent = QModelIndex());
+    Qt::ItemFlags flags(const QModelIndex &index) const;
     /*@}*/
 
     /* Add an address to the model.
diff --git a/src/qt/editaddressdialog.cpp b/src/qt/editaddressdialog.cpp
index 0d88aa47cb..5cfcb34b95 100644
--- a/src/qt/editaddressdialog.cpp
+++ b/src/qt/editaddressdialog.cpp
@@ -25,7 +25,7 @@ EditAddressDialog::EditAddressDialog(Mode mode, QWidget *parent) :
         break;
     case EditReceivingAddress:
         setWindowTitle(tr("Edit receiving address"));
-        ui->addressEdit->setDisabled(true);
+        ui->addressEdit->setEnabled(false);
         break;
     case EditSendingAddress:
         setWindowTitle(tr("Edit sending address"));
@@ -44,6 +44,9 @@ EditAddressDialog::~EditAddressDialog()
 void EditAddressDialog::setModel(AddressTableModel *model)
 {
     this->model = model;
+    if(!model)
+        return;
+
     mapper->setModel(model);
     mapper->addMapping(ui->labelEdit, AddressTableModel::Label);
     mapper->addMapping(ui->addressEdit, AddressTableModel::Address);
@@ -58,6 +61,7 @@ bool EditAddressDialog::saveCurrentRow()
 {
     if(!model)
         return false;
+
     switch(mode)
     {
     case NewReceivingAddress:
@@ -82,35 +86,39 @@ void EditAddressDialog::accept()
 {
     if(!model)
         return;
+
     if(!saveCurrentRow())
     {
         switch(model->getEditStatus())
         {
-        case AddressTableModel::DUPLICATE_ADDRESS:
-            QMessageBox::warning(this, windowTitle(),
-                tr("The entered address \"%1\" is already in the address book.").arg(ui->addressEdit->text()),
-                QMessageBox::Ok, QMessageBox::Ok);
+        case AddressTableModel::OK:
+            // Failed with unknown reason. Just reject.
+            break;
+        case AddressTableModel::NO_CHANGES:
+            // No changes were made during edit operation. Just reject.
             break;
         case AddressTableModel::INVALID_ADDRESS:
             QMessageBox::warning(this, windowTitle(),
                 tr("The entered address \"%1\" is not a valid Bitcoin address.").arg(ui->addressEdit->text()),
                 QMessageBox::Ok, QMessageBox::Ok);
-            return;
+            break;
+        case AddressTableModel::DUPLICATE_ADDRESS:
+            QMessageBox::warning(this, windowTitle(),
+                tr("The entered address \"%1\" is already in the address book.").arg(ui->addressEdit->text()),
+                QMessageBox::Ok, QMessageBox::Ok);
+            break;
         case AddressTableModel::WALLET_UNLOCK_FAILURE:
             QMessageBox::critical(this, windowTitle(),
                 tr("Could not unlock wallet."),
                 QMessageBox::Ok, QMessageBox::Ok);
-            return;
+            break;
         case AddressTableModel::KEY_GENERATION_FAILURE:
             QMessageBox::critical(this, windowTitle(),
                 tr("New key generation failed."),
                 QMessageBox::Ok, QMessageBox::Ok);
-            return;
-        case AddressTableModel::OK:
-            // Failed with unknown reason. Just reject.
             break;
-        }
 
+        }
         return;
     }
     QDialog::accept();
diff --git a/src/qt/editaddressdialog.h b/src/qt/editaddressdialog.h
index 7ec053f135..0e4183bd52 100644
--- a/src/qt/editaddressdialog.h
+++ b/src/qt/editaddressdialog.h
@@ -27,15 +27,17 @@ public:
     };
 
     explicit EditAddressDialog(Mode mode, QWidget *parent = 0);
-    ~EditAddressDialog();    
+    ~EditAddressDialog();
 
     void setModel(AddressTableModel *model);
     void loadRow(int row);
 
-    void accept();
-
     QString getAddress() const;
     void setAddress(const QString &address);
+
+public slots:
+    void accept();
+
 private:
     bool saveCurrentRow();