Observe case insensitive file systems in QFileDialog::selectFile().

When stripping the root path from a file name that cannot be found
in the model, use case sensitive comparison depending on
file system.

Task-number: QTBUG-38162
Change-Id: I28e28973fca2da35a5768fdd00cc258b9669a15a
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>

src/widgets/dialogs/qfiledialog.cpp

@@ -71,6 +71,7 @@ extern bool qt_priv_ptr_valid;
 #endif
 #if defined(Q_OS_UNIX)
 #include <pwd.h>
+#include <unistd.h> // for pathconf() on OS X
 #elif defined(Q_OS_WIN)
 #  include <QtCore/qt_windows.h>
 #endif
@@ -1018,6 +1019,44 @@ QUrl QFileDialog::directoryUrl() const
         return QUrl::fromLocalFile(directory().absolutePath());
 }
 
+// FIXME Qt 5.4: Use upcoming QVolumeInfo class to determine this information?
+static inline bool isCaseSensitiveFileSystem(const QString &path)
+{
+    Q_UNUSED(path)
+#if defined(Q_OS_WIN)
+    // Return case insensitive unconditionally, even if someone has a case sensitive
+    // file system mounted, wrongly capitalized drive letters will cause mismatches.
+    return false;
+#elif defined(Q_OS_OSX)
+    return pathconf(QFile::encodeName(path).constData(), _PC_CASE_SENSITIVE);
+#else
+    return true;
+#endif
+}
+
+// Determine the file name to be set on the line edit from the path
+// passed to selectFile() in mode QFileDialog::AcceptSave.
+static inline QString fileFromPath(const QString &rootPath, QString path)
+{
+    if (!QFileInfo(path).isAbsolute())
+        return path;
+    if (path.startsWith(rootPath, isCaseSensitiveFileSystem(rootPath) ? Qt::CaseSensitive : Qt::CaseInsensitive))
+        path.remove(0, rootPath.size());
+
+    if (path.isEmpty())
+        return path;
+
+    if (path.at(0) == QDir::separator()
+#ifdef Q_OS_WIN
+            //On Windows both cases can happen
+            || path.at(0) == QLatin1Char('/')
+#endif
+            ) {
+            path.remove(0, 1);
+    }
+    return path;
+}
+
 /*!
     Selects the given \a filename in the file dialog.
 
@@ -1049,28 +1088,9 @@ void QFileDialog::selectFile(const QString &filename)
     }
 
     QModelIndex index = d->model->index(filename);
-    QString file;
-    if (!index.isValid()) {
-        // save as dialog where we want to input a default value
-        QString text = filename;
-        if (QFileInfo(filename).isAbsolute()) {
-            QString current = d->rootPath();
-            text.remove(current);
-            if (text.at(0) == QDir::separator()
-#ifdef Q_OS_WIN
-                //On Windows both cases can happen
-                || text.at(0) == QLatin1Char('/')
-#endif
-                )
-                text = text.remove(0,1);
-        }
-        file = text;
-    } else {
-        file = index.data().toString();
-    }
     d->qFileDialogUi->listView->selectionModel()->clear();
     if (!isVisible() || !d->lineEdit()->hasFocus())
-        d->lineEdit()->setText(file);
+        d->lineEdit()->setText(index.isValid() ? index.data().toString() : fileFromPath(d->rootPath(), filename));
 }
 
 /*!

tests/auto/widgets/dialogs/qfiledialog/tst_qfiledialog.cpp

@@ -43,6 +43,7 @@
 #include <QtTest/QtTest>
 
 #include <qcoreapplication.h>
+#include <qfile.h>
 #include <qdebug.h>
 #include <qsharedpointer.h>
 #include <qfiledialog.h>
@@ -72,6 +73,7 @@
 #include <QFileSystemModel>
 
 #if defined(Q_OS_UNIX)
+#include <unistd.h> // for pathconf() on OS X
 #ifdef QT_BUILD_INTERNAL
 QT_BEGIN_NAMESPACE
 extern Q_GUI_EXPORT QString qt_tildeExpansion(const QString &path, bool *expanded = 0);
@@ -79,6 +81,19 @@ QT_END_NAMESPACE
 #endif
 #endif
 
+static inline bool isCaseSensitiveFileSystem(const QString &path)
+{
+    Q_UNUSED(path)
+#if defined(Q_OS_MAC)
+    return pathconf(QFile::encodeName(path).constData(), _PC_CASE_SENSITIVE);
+#elif defined(Q_OS_WIN)
+    return false;
+#else
+    return true;
+#endif
+}
+
+
 class QNonNativeFileDialog : public QFileDialog
 {
     Q_OBJECT
@@ -130,6 +145,7 @@ private slots:
     void selectFile_data();
     void selectFile();
     void selectFiles();
+    void selectFileWrongCaseSaveAs();
     void selectFilter();
     void viewMode();
     void proxymodel();
@@ -882,6 +898,27 @@ void tst_QFiledialog::selectFile()
     fd.reset(); // Ensure the file dialog let's go of the temporary file for "temp".
 }
 
+void tst_QFiledialog::selectFileWrongCaseSaveAs()
+{
+    const QString home = QDir::homePath();
+    if (isCaseSensitiveFileSystem(home))
+        QSKIP("This test is intended for case-insensitive file systems only.");
+    // QTBUG-38162: when passing a wrongly capitalized path to selectFile()
+    // on a case-insensitive file system, the line edit should only
+    // contain the file name ("c:\PRogram files\foo.txt" -> "foo.txt").
+    const QString fileName = QStringLiteral("foo.txt");
+    const QString path = home + QLatin1Char('/') + fileName;
+    QString wrongCasePath = path;
+    for (int c = 0; c < wrongCasePath.size(); c += 2)
+        wrongCasePath[c] = wrongCasePath.at(c).isLower() ? wrongCasePath.at(c).toUpper() : wrongCasePath.at(c).toLower();
+    QNonNativeFileDialog fd(0, "QTBUG-38162", wrongCasePath);
+    fd.setAcceptMode(QFileDialog::AcceptSave);
+    fd.selectFile(wrongCasePath);
+    const QLineEdit *lineEdit = fd.findChild<QLineEdit*>("fileNameEdit");
+    QVERIFY(lineEdit);
+    QCOMPARE(lineEdit->text().compare(fileName, Qt::CaseInsensitive), 0);
+}
+
 void tst_QFiledialog::selectFiles()
 {
     QTemporaryDir tempDir;