Windows QPA/File dialog: Refactor code copying non-file shell items

Remove the canCopy() check which is not required and pass up the error
message. Remove special characters and use the base name of the display name
which can be an URL.

Task-number: QTBUG-71785
Change-Id: I22966cb8d1f5bca0bbca71cf3ebe66e4ede1a747
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>
Reviewed-by: Andre de la Rocha <andre.rocha@qt.io>

src/plugins/platforms/windows/qwindowsdialoghelpers.cpp

@@ -569,12 +569,10 @@ public:
 
     bool isFileSystem() const  { return (m_attributes & SFGAO_FILESYSTEM) != 0; }
     bool isDir() const         { return (m_attributes & SFGAO_FOLDER) != 0; }
-    // Copy using IFileOperation
-    bool canCopy() const       { return (m_attributes & SFGAO_CANCOPY) != 0; }
     // Supports IStream
     bool canStream() const     { return (m_attributes & SFGAO_STREAM) != 0; }
 
-    bool copyData(QIODevice *out);
+    bool copyData(QIODevice *out, QString *errorMessage);
 
     static IShellItems itemsFromItemArray(IShellItemArray *items);
 
@@ -666,14 +664,19 @@ QWindowsShellItem::IShellItems QWindowsShellItem::itemsFromItemArray(IShellItemA
     return result;
 }
 
-bool QWindowsShellItem::copyData(QIODevice *out)
+bool QWindowsShellItem::copyData(QIODevice *out, QString *errorMessage)
 {
-    if (!canCopy() || !canStream())
+    if (!canStream()) {
+        *errorMessage = QLatin1String("Item not streamable");
         return false;
+    }
     IStream *istream = nullptr;
     HRESULT hr = m_item->BindToHandler(nullptr, BHID_Stream, IID_PPV_ARGS(&istream));
-    if (FAILED(hr))
+    if (FAILED(hr)) {
+        *errorMessage = QLatin1String("BindToHandler() failed: ")
+                        + QLatin1String(QWindowsContext::comErrorString(hr));
         return false;
+    }
     enum : ULONG { bufSize = 102400 };
     char buffer[bufSize];
     ULONG bytesRead;
@@ -686,7 +689,12 @@ bool QWindowsShellItem::copyData(QIODevice *out)
             break;
     }
     istream->Release();
-    return hr == S_OK || hr == S_FALSE;
+    if (hr != S_OK && hr != S_FALSE) {
+        *errorMessage = QLatin1String("Read() failed: ")
+                        + QLatin1String(QWindowsContext::comErrorString(hr));
+        return false;
+    }
+    return true;
 }
 
 // Helper for "Libraries": collections of folders appearing from Windows 7
@@ -735,8 +743,6 @@ void QWindowsShellItem::format(QDebug &d) const
         d << " [dir]";
     if (canStream())
         d << " [stream]";
-    if (canCopy())
-        d << " [copyable]";
     d << ", normalDisplay=\"" << normalDisplay()
         << "\", desktopAbsoluteParsing=\"" << desktopAbsoluteParsing()
         << "\", urlString=\"" << urlString() << "\", fileSysPath=\"" << fileSysPath() << '"';
@@ -1395,21 +1401,50 @@ static void cleanupTemporaryItemCopies()
         QFile::remove(file);
 }
 
-static QString createTemporaryItemCopy(QWindowsShellItem &qItem)
-{
-    if (!qItem.canCopy() || !qItem.canStream())
-        return QString();
-    QString pattern = qItem.normalDisplay();
-    const int lastDot = pattern.lastIndexOf(QLatin1Char('.'));
-    const QString placeHolder = QStringLiteral("_XXXXXX");
-    if (lastDot >= 0)
-        pattern.insert(lastDot, placeHolder);
-    else
-        pattern.append(placeHolder);
+// Determine temporary file pattern from a shell item's display
+// name. This can be a URL.
 
-    QTemporaryFile targetFile(QDir::tempPath() + QLatin1Char('/') + pattern);
+static bool validFileNameCharacter(QChar c)
+{
+    return c.isLetterOrNumber() || c == QLatin1Char('_') || c == QLatin1Char('-');
+}
+
+QString tempFilePattern(QString name)
+{
+    const int lastSlash = qMax(name.lastIndexOf(QLatin1Char('/')),
+                               name.lastIndexOf(QLatin1Char('\\')));
+    if (lastSlash != -1)
+        name.remove(0, lastSlash + 1);
+
+    int lastDot = name.lastIndexOf(QLatin1Char('.'));
+    if (lastDot < 0)
+        lastDot = name.size();
+    name.insert(lastDot, QStringLiteral("_XXXXXX"));
+
+    for (int i = lastDot - 1; i >= 0; --i) {
+        if (!validFileNameCharacter(name.at(i)))
+            name[i] = QLatin1Char('_');
+    }
+
+    name.prepend(QDir::tempPath() + QLatin1Char('/'));
+    return name;
+}
+
+static QString createTemporaryItemCopy(QWindowsShellItem &qItem, QString *errorMessage)
+{
+    if (!qItem.canStream()) {
+        *errorMessage = QLatin1String("Item not streamable");
+        return QString();
+    }
+
+    QTemporaryFile targetFile(tempFilePattern(qItem.normalDisplay()));
     targetFile.setAutoRemove(false);
-    if (!targetFile.open() || !qItem.copyData(&targetFile))
+    if (!targetFile.open())  {
+        *errorMessage = QLatin1String("Cannot create temporary file: ")
+                        + targetFile.errorString();
+        return QString();
+    }
+    if (!qItem.copyData(&targetFile, errorMessage))
         return QString();
     const QString result = targetFile.fileName();
     if (temporaryItemCopies()->isEmpty())
@@ -1427,11 +1462,14 @@ QList<QUrl> QWindowsNativeOpenFileDialog::dialogResult() const
             QWindowsShellItem qItem(item);
             const QString path = qItem.path();
             if (path.isEmpty() && !qItem.isDir()) {
-                const QString temporaryCopy = createTemporaryItemCopy(qItem);
-                if (temporaryCopy.isEmpty())
-                    qWarning() << "Unable to create a local copy of" << qItem;
-                else
+                QString errorMessage;
+                const QString temporaryCopy = createTemporaryItemCopy(qItem, &errorMessage);
+                if (temporaryCopy.isEmpty()) {
+                    qWarning().noquote() << "Unable to create a local copy of" << qItem
+                        << ": " << errorMessage;
+                } else {
                     result.append(QUrl::fromLocalFile(temporaryCopy));
+                }
             } else {
                 result.append(qItem.url());
             }