Allow selecting any open database in unlock dialog

When showing the database unlock dialog from browser or auto-type and
there's more than one open database, replace the filename label with
a drop-down box of all available files. Switching the filename here will
change the active tab of the main window and unlock it.

This is the first part of an implementation for
keepassxreboot#2322

TODO/Limitations:
  * The drop-down list should show only locked databases rather than all
    open databases.
  * The drop-down should dynamically respond if the set of open database
    tabs is changed (e.g. if the user closes a database in the main
    window while the unlock dialog is open)
  * No handling for the case where the active database is unlocked but
    has no matching credentials, and there's other locked databases open
    ("Case 2" in the github issue)

src/gui/DatabaseOpenDialog.cpp

@@ -17,6 +17,7 @@
 
 #include "DatabaseOpenDialog.h"
 #include "DatabaseOpenWidget.h"
+#include "DatabaseTabWidget.h"
 #include "DatabaseWidget.h"
 #include "core/Database.h"
 
@@ -38,6 +39,28 @@ DatabaseOpenDialog::DatabaseOpenDialog(QWidget* parent)
     setMinimumWidth(700);
 }
 
+void DatabaseOpenDialog::setMultiFile(bool multiFile)
+{
+    if (multiFile) {
+        auto* tabWidget = qobject_cast<const DatabaseTabWidget*>(parentWidget());
+        if (!tabWidget) {
+            m_view->clearMultiFileList();
+            return;
+        }
+        QStringList fileList;
+        for (int i = 0, c = tabWidget->count(); i < c; ++i) {
+            auto* dbWidget = tabWidget->databaseWidgetFromIndex(i);
+            Q_ASSERT(dbWidget);
+            if (dbWidget) {
+                fileList << dbWidget->database()->filePath();
+            }
+        }
+        m_view->setMultiFileList(fileList);
+    } else {
+        m_view->clearMultiFileList();
+    }
+}
+
 void DatabaseOpenDialog::setFilePath(const QString& filePath)
 {
     m_view->load(filePath);
@@ -67,6 +90,25 @@ DatabaseOpenDialog::Intent DatabaseOpenDialog::intent() const
     return m_intent;
 }
 
+void DatabaseOpenDialog::changeFile(const QString& filePath)
+{
+    auto* tabWidget = qobject_cast<DatabaseTabWidget*>(parentWidget());
+    if (!tabWidget) {
+        return;
+    }
+
+    auto* dbWidget = tabWidget->databaseWidgetFromFilePath(filePath);
+    if (dbWidget) {
+        setTargetDatabaseWidget(dbWidget);
+        tabWidget->setCurrentIndex(tabWidget->indexOf(dbWidget));
+        setFilePath(filePath);
+    } else {
+        // no matching dbWidget for the filePath, it probably got closed while this dialog was open.
+        // cancel and let the user start over.
+        complete(false);
+    }
+}
+
 void DatabaseOpenDialog::clearForms()
 {
     m_view->clearForms();

src/gui/DatabaseOpenDialog.h

@@ -44,6 +44,7 @@ class DatabaseOpenDialog : public QDialog
     explicit DatabaseOpenDialog(QWidget* parent = nullptr);
     void setFilePath(const QString& filePath);
     void setTargetDatabaseWidget(DatabaseWidget* dbWidget);
+    void setMultiFile(bool multiFile);
     void setIntent(Intent intent);
     Intent intent() const;
     QSharedPointer<Database> database();
@@ -54,6 +55,7 @@ class DatabaseOpenDialog : public QDialog
 
 public slots:
     void complete(bool accepted);
+    void changeFile(const QString& filePath);
 
 private:
     QPointer<DatabaseOpenWidget> m_view;

src/gui/DatabaseOpenWidget.cpp

@@ -24,6 +24,7 @@
 #include "core/Resources.h"
 #include "crypto/Random.h"
 #include "format/KeePass2Reader.h"
+#include "gui/DatabaseOpenDialog.h"
 #include "gui/FileDialog.h"
 #include "gui/MainWindow.h"
 #include "gui/MessageBox.h"
@@ -138,14 +139,49 @@ void DatabaseOpenWidget::hideEvent(QHideEvent* event)
     }
 }
 
+/**
+ * Set a list of files in a drop-down to choose a different database.
+ * Must be called before load(), and should only be called by DatabaseOpenDialog
+ */
+void DatabaseOpenWidget::setMultiFileList(const QStringList& filenameList)
+{
+    m_multiFileList = filenameList;
+}
+
+void DatabaseOpenWidget::clearMultiFileList()
+{
+    m_multiFileList.clear();
+}
+
 void DatabaseOpenWidget::load(const QString& filename)
 {
     clearForms();
 
     m_filename = filename;
-    m_ui->fileNameLabel->setRawText(m_filename);
+
+    if (m_multiFileList.count() > 1) {
+        m_ui->fileNameLabel->setVisible(false);
+        m_ui->fileNameList->addItems(m_multiFileList);
+        m_ui->fileNameList->setCurrentText(filename);
+        m_ui->fileNameList->setVisible(true);
+
+        // changing the file in a dropdown needs to go back up the parent tree to change the current database tab.
+        // The handler of this signal will come back and call load() here again.
+        auto* parentDialog = qobject_cast<DatabaseOpenDialog*>(parentWidget());
+        if (parentDialog) {
+            // clang-format off
+            connect(m_ui->fileNameList, SIGNAL(textActivated(const QString&)),
+                    parentDialog, SLOT(changeFile(const QString&)));
+            // clang-format on
+        }
+    } else {
+        m_ui->fileNameLabel->setRawText(m_filename);
+        m_ui->fileNameLabel->setVisible(true);
+        m_ui->fileNameList->setVisible(false);
+    }
 
     m_ui->keyFileClearIcon->setVisible(false);
+    m_ui->editPassword->setFocus();
 
     if (config()->get(Config::RememberLastKeyFiles).toBool()) {
         auto lastKeyFiles = config()->get(Config::LastKeyFiles).toHash();
@@ -170,6 +206,8 @@ void DatabaseOpenWidget::load(const QString& filename)
 
 void DatabaseOpenWidget::clearForms()
 {
+    disconnect(m_ui->fileNameList, SIGNAL(textActivated(const QString&)), nullptr, nullptr);
+    m_ui->fileNameList->clear();
     m_ui->editPassword->setText("");
     m_ui->editPassword->setShowPassword(false);
     m_ui->keyFileLineEdit->clear();

src/gui/DatabaseOpenWidget.h

@@ -45,6 +45,8 @@ class DatabaseOpenWidget : public DialogyWidget
     void clearForms();
     void enterKey(const QString& pw, const QString& keyFile);
     QSharedPointer<Database> database();
+    void setMultiFileList(const QStringList& filenameList);
+    void clearMultiFileList();
 
 signals:
     void dialogFinished(bool accepted);
@@ -57,6 +59,7 @@ class DatabaseOpenWidget : public DialogyWidget
     const QScopedPointer<Ui::DatabaseOpenWidget> m_ui;
     QSharedPointer<Database> m_db;
     QString m_filename;
+    QStringList m_multiFileList;
     bool m_retryUnlockWithEmptyPassword = false;
 
 protected slots:

src/gui/DatabaseOpenWidget.ui

@@ -90,6 +90,13 @@
           </property>
          </widget>
         </item>
+        <item>
+         <widget class="QComboBox" name="fileNameList">
+          <property name="visible">
+           <bool>false</bool>
+          </property>
+         </widget>
+        </item>
         <item>
          <spacer name="verticalSpacer_3">
           <property name="orientation">

src/gui/DatabaseTabWidget.cpp

@@ -619,6 +619,18 @@ DatabaseWidget* DatabaseTabWidget::currentDatabaseWidget()
     return qobject_cast<DatabaseWidget*>(currentWidget());
 }
 
+DatabaseWidget* DatabaseTabWidget::databaseWidgetFromFilePath(const QString& filePath) const
+{
+    for (int i = 0, c = count(); i < c; ++i) {
+        auto* dbWidget = databaseWidgetFromIndex(i);
+        Q_ASSERT(dbWidget);
+        if (dbWidget && (dbWidget->database()->filePath() == filePath)) {
+            return dbWidget;
+        }
+    }
+    return nullptr;
+}
+
 /**
  * Attempt to lock all open databases
  *
@@ -666,6 +678,8 @@ void DatabaseTabWidget::unlockDatabaseInDialog(DatabaseWidget* dbWidget,
 {
     m_databaseOpenDialog->setTargetDatabaseWidget(dbWidget);
     m_databaseOpenDialog->setIntent(intent);
+    m_databaseOpenDialog->setMultiFile(intent == DatabaseOpenDialog::Intent::AutoType
+                                       || intent == DatabaseOpenDialog::Intent::Browser);
     m_databaseOpenDialog->setFilePath(filePath);
 
 #ifdef Q_OS_MACOS

src/gui/DatabaseTabWidget.h

@@ -41,6 +41,7 @@ class DatabaseTabWidget : public QTabWidget
     QString tabName(int index);
     DatabaseWidget* currentDatabaseWidget();
     DatabaseWidget* databaseWidgetFromIndex(int index) const;
+    DatabaseWidget* databaseWidgetFromFilePath(const QString& filePath) const;
 
     bool isReadOnly(int index = -1) const;
     bool canSave(int index = -1) const;