Add visual feedback for wrong paths in FileSystemPathEdit

src/gui/fspathedit.cpp

@@ -80,6 +80,7 @@ class FileSystemPathEdit::FileSystemPathEditPrivate
     Mode m_mode;
     QString m_lastSignaledPath;
     QString m_dialogCaption;
+    Private::FileSystemPathValidator *m_validator;
 };
 
 FileSystemPathEdit::FileSystemPathEditPrivate::FileSystemPathEditPrivate(
@@ -89,6 +90,7 @@ FileSystemPathEdit::FileSystemPathEditPrivate::FileSystemPathEditPrivate(
     , m_browseAction {new QAction(q)}
     , m_browseBtn {new QToolButton(q)}
     , m_mode {FileSystemPathEdit::Mode::FileOpen}
+    , m_validator {new Private::FileSystemPathValidator(q)}
 {
     m_browseAction->setIconText(browseButtonBriefText.tr());
     m_browseAction->setText(browseButtonFullText.tr());
@@ -97,6 +99,8 @@ FileSystemPathEdit::FileSystemPathEditPrivate::FileSystemPathEditPrivate(
     m_browseBtn->setDefaultAction(m_browseAction);
     m_fileNameFilter = tr("Any file") + QLatin1String(" (*)");
     m_editor->setBrowseAction(m_browseAction);
+    m_validator->setStrictMode(false);
+    m_editor->setValidator(m_validator);
     modeChanged();
 }
 
@@ -163,6 +167,11 @@ void FileSystemPathEdit::FileSystemPathEditPrivate::modeChanged()
     }
     m_browseAction->setIcon(QApplication::style()->standardIcon(pixmap));
     m_editor->completeDirectoriesOnly(showDirsOnly);
+
+    m_validator->setExistingOnly(m_mode != FileSystemPathEdit::Mode::FileSave);
+    m_validator->setDirectoriesOnly((m_mode == FileSystemPathEdit::Mode::DirectoryOpen) || (m_mode == FileSystemPathEdit::Mode::DirectorySave));
+    m_validator->setCheckReadPermission((m_mode == FileSystemPathEdit::Mode::FileOpen) || (m_mode == FileSystemPathEdit::Mode::DirectoryOpen));
+    m_validator->setCheckWritePermission((m_mode == FileSystemPathEdit::Mode::FileSave) || (m_mode == FileSystemPathEdit::Mode::DirectorySave));
 }
 
 FileSystemPathEdit::FileSystemPathEdit(Private::FileEditorWithCompletion *editor, QWidget *parent)

src/gui/fspathedit_p.cpp

@@ -29,13 +29,178 @@
 #include "fspathedit_p.h"
 
 #include <QCompleter>
+#include <QDir>
 #include <QFileInfo>
+#include <QStringList>
+#include <QStyle>
+
+// -------------------- FileSystemPathValidator ----------------------------------------
+Private::FileSystemPathValidator::FileSystemPathValidator(QObject *parent)
+    : QValidator(parent)
+    , m_strictMode(false)
+    , m_existingOnly(false)
+    , m_directoriesOnly(false)
+    , m_checkReadPermission(false)
+    , m_checkWritePermission(false)
+{
+}
+
+bool Private::FileSystemPathValidator::strictMode() const
+{
+    return m_strictMode;
+}
+
+void Private::FileSystemPathValidator::setStrictMode(bool v)
+{
+    m_strictMode = v;
+}
+
+bool Private::FileSystemPathValidator::existingOnly() const
+{
+    return m_existingOnly;
+}
+
+void Private::FileSystemPathValidator::setExistingOnly(bool v)
+{
+    m_existingOnly = v;
+}
+
+bool Private::FileSystemPathValidator::directoriesOnly() const
+{
+    return m_directoriesOnly;
+}
+
+void Private::FileSystemPathValidator::setDirectoriesOnly(bool v)
+{
+    m_directoriesOnly = v;
+}
+
+bool Private::FileSystemPathValidator::checkReadPermission() const
+{
+    return m_checkReadPermission;
+}
+
+void Private::FileSystemPathValidator::setCheckReadPermission(bool v)
+{
+    m_checkReadPermission = v;
+}
+
+bool Private::FileSystemPathValidator::checkWritePermission() const
+{
+    return m_checkWritePermission;
+}
+
+void Private::FileSystemPathValidator::setCheckWritePermission(bool v)
+{
+    m_checkWritePermission = v;
+}
+
+QValidator::State Private::FileSystemPathValidator::validate(QString &input, int &pos) const
+{
+    if (input.isEmpty())
+        return m_strictMode ? QValidator::Invalid : QValidator::Intermediate;
+
+    // we test path components from beginning to the one with cursor location in strict mode
+    // and the one with cursor and beyond in non-strict mode
+    QVector<QStringRef> components = input.splitRef(QDir::separator(), QString::KeepEmptyParts);
+    // find index of the component that contains pos
+    int componentWithCursorIndex = 0;
+    int pathLength = 0;
+
+    // components.size() - 1 because when path ends with QDir::separator(), we will not see the last
+    // character in the components array, yet everything past the one before the last delimiter
+    // belongs to the last component
+    for (; (componentWithCursorIndex < components.size() - 1) && (pathLength < pos); ++componentWithCursorIndex) {
+        pathLength = components[componentWithCursorIndex].position() + components[componentWithCursorIndex].size();
+    }
+
+    Q_ASSERT(componentWithCursorIndex < components.size());
+
+    m_lastValidationState = QValidator::Acceptable;
+    if (componentWithCursorIndex > 0)
+        m_lastValidationState = validate(input, components, m_strictMode, 0, componentWithCursorIndex - 1);
+    if ((m_lastValidationState == QValidator::Acceptable) && (componentWithCursorIndex < components.size()))
+        m_lastValidationState = validate(input, components, false, componentWithCursorIndex, components.size() - 1);
+    return m_lastValidationState;
+}
+
+QValidator::State Private::FileSystemPathValidator::validate(const QString &path, const QVector<QStringRef> &pathComponents, bool strict,
+                                                             int firstComponentToTest, int lastComponentToTest) const
+{
+    Q_ASSERT(firstComponentToTest >= 0);
+    Q_ASSERT(lastComponentToTest >= firstComponentToTest);
+    Q_ASSERT(lastComponentToTest < pathComponents.size());
+
+    m_lastTestResult = TestResult::DoesNotExist;
+    if (pathComponents.empty())
+        return strict ? QValidator::Invalid : QValidator::Intermediate;
+
+    for (int i = firstComponentToTest; i < lastComponentToTest; ++i) {
+        if (pathComponents[i].isEmpty()) continue;
+
+        QStringRef componentPath(&path, 0, pathComponents[i].position() + pathComponents[i].size());
+        m_lastTestResult = testPath(componentPath, false);
+        if (m_lastTestResult != TestResult::OK) {
+            m_lastTestedPath = componentPath.toString();
+            return strict ? QValidator::Invalid : QValidator::Intermediate;
+        }
+    }
+
+    const bool finalPath = (lastComponentToTest == (pathComponents.size() - 1));
+    QStringRef componentPath(&path, 0, pathComponents[lastComponentToTest].position()
+                                + pathComponents[lastComponentToTest].size());
+    m_lastTestResult = testPath(componentPath, finalPath);
+    if (m_lastTestResult != TestResult::OK) {
+        m_lastTestedPath = componentPath.toString();
+        return strict ? QValidator::Invalid : QValidator::Intermediate;
+    }
+    return QValidator::Acceptable;
+}
+
+Private::FileSystemPathValidator::TestResult
+Private::FileSystemPathValidator::testPath(const QStringRef &path, bool pathIsComplete) const
+{
+    QFileInfo fi(path.toString());
+    if (m_existingOnly && !fi.exists())
+        return TestResult::DoesNotExist;
+
+    if ((!pathIsComplete || m_directoriesOnly) && !fi.isDir())
+        return TestResult::NotADir;
+
+    if (pathIsComplete) {
+        if (!m_directoriesOnly && fi.isDir())
+            return TestResult::NotAFile;
+
+        if (m_checkWritePermission && (fi.exists() && !fi.isWritable()))
+            return TestResult::CantWrite;
+        if (m_checkReadPermission && !fi.isReadable())
+            return TestResult::CantRead;
+    }
+
+    return TestResult::OK;
+}
+
+Private::FileSystemPathValidator::TestResult Private::FileSystemPathValidator::lastTestResult() const
+{
+    return m_lastTestResult;
+}
+
+QValidator::State Private::FileSystemPathValidator::lastValidationState() const
+{
+    return m_lastValidationState;
+}
+
+QString Private::FileSystemPathValidator::lastTestedPath() const
+{
+    return m_lastTestedPath;
+}
 
 Private::FileLineEdit::FileLineEdit(QWidget *parent)
     : QLineEdit {parent}
     , m_completerModel {new QFileSystemModel(this)}
     , m_completer {new QCompleter(this)}
     , m_browseAction {nullptr}
+    , m_warningAction {nullptr}
 {
     m_completerModel->setRootPath("");
     m_completerModel->setIconProvider(&m_iconProvider);
@@ -68,6 +233,11 @@ void Private::FileLineEdit::setBrowseAction(QAction *action)
     m_browseAction = action;
 }
 
+void Private::FileLineEdit::setValidator(QValidator *validator)
+{
+    QLineEdit::setValidator(validator);
+}
+
 QWidget *Private::FileLineEdit::widget()
 {
     return this;
@@ -80,6 +250,33 @@ void Private::FileLineEdit::keyPressEvent(QKeyEvent *e)
         m_completerModel->setRootPath(QFileInfo(text()).absoluteDir().absolutePath());
         showCompletionPopup();
     }
+
+    const FileSystemPathValidator *validator =
+        qobject_cast<const FileSystemPathValidator *>(this->validator());
+    if (validator) {
+        FileSystemPathValidator::TestResult lastTestResult = validator->lastTestResult();
+        QValidator::State lastState = validator->lastValidationState();
+        if (lastTestResult == FileSystemPathValidator::TestResult::OK) {
+            if (m_warningAction) {
+                delete m_warningAction;
+                m_warningAction = nullptr;
+            }
+        }
+        else {
+            if (!m_warningAction) {
+                m_warningAction = new QAction(this);
+                addAction(m_warningAction, QLineEdit::TrailingPosition);
+            }
+        }
+
+        if (m_warningAction) {
+            if (lastState == QValidator::Invalid)
+                m_warningAction->setIcon(style()->standardIcon(QStyle::SP_MessageBoxCritical));
+            else if (lastState == QValidator::Intermediate)
+                m_warningAction->setIcon(style()->standardIcon(QStyle::SP_MessageBoxWarning));
+            m_warningAction->setToolTip(warningText(lastTestResult).arg(validator->lastTestedPath()));
+        }
+    }
 }
 
 void Private::FileLineEdit::contextMenuEvent(QContextMenuEvent *event)
@@ -100,6 +297,25 @@ void Private::FileLineEdit::showCompletionPopup()
     m_completer->complete();
 }
 
+QString Private::FileLineEdit::warningText(FileSystemPathValidator::TestResult r)
+{
+    using TestResult = FileSystemPathValidator::TestResult;
+    switch (r) {
+    case TestResult::DoesNotExist:
+        return tr("'%1' does not exist");
+    case TestResult::NotADir:
+        return tr("'%1' does not point to a directory");
+    case TestResult::NotAFile:
+        return tr("'%1' does not point to a file");
+    case TestResult::CantRead:
+        return tr("Does not have read permission in '%1'");
+    case TestResult::CantWrite:
+        return tr("Does not have write permission in '%1'");
+    default:
+        return QString();
+    }
+}
+
 Private::FileComboEdit::FileComboEdit(QWidget *parent)
     : QComboBox {parent}
 {
@@ -117,6 +333,11 @@ void Private::FileComboEdit::setBrowseAction(QAction *action)
     static_cast<FileLineEdit *>(lineEdit())->setBrowseAction(action);
 }
 
+void Private::FileComboEdit::setValidator(QValidator *validator)
+{
+    lineEdit()->setValidator(validator);
+}
+
 void Private::FileComboEdit::setFilenameFilters(const QStringList &filters)
 {
     static_cast<FileLineEdit *>(lineEdit())->setFilenameFilters(filters);

src/gui/fspathedit_p.h

@@ -39,9 +39,69 @@
 #include <QKeyEvent>
 #include <QLineEdit>
 #include <QMenu>
+#include <QStringRef>
+#include <QValidator>
+#include <QVector>
+
+class QStringList;
 
 namespace Private
 {
+    class FileSystemPathValidator: public QValidator
+    {
+        Q_OBJECT
+
+    public:
+        FileSystemPathValidator(QObject *parent = nullptr);
+
+        bool strictMode() const;
+        void setStrictMode(bool v);
+
+        bool existingOnly() const;
+        void setExistingOnly(bool v);
+
+        bool directoriesOnly() const;
+        void setDirectoriesOnly(bool v);
+
+        bool checkReadPermission() const;
+        void setCheckReadPermission(bool v);
+
+        bool checkWritePermission() const;
+        void setCheckWritePermission(bool v);
+
+        QValidator::State validate(QString &input, int &pos) const override;
+
+        enum class TestResult
+        {
+            OK,
+            DoesNotExist,
+            NotADir,
+            NotAFile,
+            CantRead,
+            CantWrite
+        };
+
+        TestResult lastTestResult() const;
+        QValidator::State lastValidationState() const;
+        QString lastTestedPath() const;
+
+    private:
+        QValidator::State validate(const QString &path, const QVector<QStringRef> &pathComponents, bool strict,
+                                   int firstComponentToTest, int lastComponentToTest) const;
+
+        TestResult testPath(const QStringRef &path, bool pathIsComplete) const;
+
+        bool m_strictMode;
+        bool m_existingOnly;
+        bool m_directoriesOnly;
+        bool m_checkReadPermission;
+        bool m_checkWritePermission;
+
+        mutable TestResult m_lastTestResult;
+        mutable QValidator::State m_lastValidationState;
+        mutable QString m_lastTestedPath;
+    };
+
     class FileEditorWithCompletion
     {
     public:
@@ -49,6 +109,7 @@ namespace Private
         virtual void completeDirectoriesOnly(bool completeDirsOnly) = 0;
         virtual void setFilenameFilters(const QStringList &filters) = 0;
         virtual void setBrowseAction(QAction *action) = 0;
+        virtual void setValidator(QValidator *validator) = 0;
         virtual QWidget *widget() = 0;
     };
 
@@ -64,6 +125,7 @@ namespace Private
         void completeDirectoriesOnly(bool completeDirsOnly) override;
         void setFilenameFilters(const QStringList &filters) override;
         void setBrowseAction(QAction *action) override;
+        void setValidator(QValidator *validator) override;
         QWidget *widget() override;
 
     protected:
@@ -74,13 +136,15 @@ namespace Private
         void showCompletionPopup();
 
     private:
+        static QString warningText(FileSystemPathValidator::TestResult r);
+
         QFileSystemModel *m_completerModel;
         QCompleter *m_completer;
         QAction *m_browseAction;
         QFileIconProvider m_iconProvider;
+        QAction *m_warningAction;
     };
 
-
     class FileComboEdit: public QComboBox, public FileEditorWithCompletion
     {
         Q_OBJECT
@@ -91,6 +155,7 @@ namespace Private
         void completeDirectoriesOnly(bool completeDirsOnly) override;
         void setFilenameFilters(const QStringList &filters) override;
         void setBrowseAction(QAction *action) override;
+        void setValidator(QValidator *validator) override;
         QWidget *widget() override;
 
     protected: