4 files changed, 50 insertions, 16 deletions

diff --git a/src/libs/installer/directoryguard.cpp b/src/libs/installer/directoryguard.cpp
index 9c97130a4..014d213d7 100644
--- a/src/libs/installer/directoryguard.cpp
+++ b/src/libs/installer/directoryguard.cpp
@@ -28,6 +28,7 @@
 
 #include "directoryguard.h"
 
+#include "fileutils.h"
 #include "globals.h"
 #include "errors.h"
 
@@ -92,8 +93,7 @@ QStringList DirectoryGuard::tryCreate()
         toCreate = QDir(p);
     }
 
-    QDir dir(m_path);
-    m_created = dir.mkpath(m_path);
+    m_created = QInstaller::createDirectoryWithParents(m_path);
     if (!m_created) {
         throw Error(QCoreApplication::translate("DirectoryGuard",
             "Cannot create directory \"%1\".").arg(QDir::toNativeSeparators(m_path)));
diff --git a/src/libs/installer/extractarchiveoperation.cpp b/src/libs/installer/extractarchiveoperation.cpp
index 6b9ecb687..986b9d8c8 100644
--- a/src/libs/installer/extractarchiveoperation.cpp
+++ b/src/libs/installer/extractarchiveoperation.cpp
@@ -193,20 +193,7 @@ bool ExtractArchiveOperation::performOperation()
 
     QFileInfo targetDirectoryInfo(fileDirectory);
 
-    // We need to create the directory structure step-by-step to avoid a rare race condition
-    // on Windows. QDir::mkpath() doesn't check if the leading directories were created elsewhere
-    // (like from within another thread) after the initial check that the given path requires
-    // creating also parent directories.
-    //
-    // On Unix patforms this case is handled by QFileSystemEngine though.
-    QDir resourcesDir(resourcesPath);
-    if (!resourcesDir.exists())
-        resourcesDir.mkdir(resourcesPath);
-
-    QDir resourceFileDir(targetDirectoryInfo.absolutePath());
-    if (!resourceFileDir.exists())
-        resourceFileDir.mkdir(targetDirectoryInfo.absolutePath());
-
+    QInstaller::createDirectoryWithParents(targetDirectoryInfo.absolutePath());
     setDefaultFilePermissions(resourcesPath, DefaultFilePermissions::Executable);
     setDefaultFilePermissions(targetDirectoryInfo.absolutePath(), DefaultFilePermissions::Executable);
 
diff --git a/src/libs/installer/fileutils.cpp b/src/libs/installer/fileutils.cpp
index 5a89073fc..11ae397fd 100644
--- a/src/libs/installer/fileutils.cpp
+++ b/src/libs/installer/fileutils.cpp
@@ -449,6 +449,52 @@ void QInstaller::mkpath(const QString &path)
 /*!
     \internal
 
+    Creates directory \a path including all parent directories. Return \c true on
+    success, \c false otherwise.
+
+    On Windows \c QDir::mkpath() doesn't check if the leading directories were created
+    elsewhere (i.e. in another thread) after the initial check that the given path
+    requires creating also parent directories, and returns \c false.
+
+    On Unix platforms this case is handled different by QFileSystemEngine though,
+    which checks for \c EEXIST error code in case any of the recursive directories
+    could not be created.
+
+    Compared to \c QInstaller::mkpath() and \c QDir::mkpath() this function checks if
+    each parent directory to-be-created were created elsewhere.
+*/
+bool QInstaller::createDirectoryWithParents(const QString &path)
+{
+    if (path.isEmpty())
+        return false;
+
+    QFileInfo dirInfo(path);
+    if (dirInfo.exists() && dirInfo.isDir())
+        return true;
+
+    // bail out if we are at the root directory
+    if (dirInfo.isRoot())
+        return false;
+
+    QDir dir(path);
+    if (dir.mkdir(path))
+        return true;
+
+    // mkdir failed, try to create the parent directory
+    if (!createDirectoryWithParents(dirInfo.absolutePath()))
+        return false;
+
+    // now try again
+    if (dir.mkdir(path))
+        return true;
+
+    // directory may be have also been created elsewhere
+    return (dirInfo.exists() && dirInfo.isDir());
+}
+
+/*!
+    \internal
+
     Generates and returns a temporary file name. The name can start with
     a template \a templ.
 */
diff --git a/src/libs/installer/fileutils.h b/src/libs/installer/fileutils.h
index 8b79ce052..1114cd60c 100644
--- a/src/libs/installer/fileutils.h
+++ b/src/libs/installer/fileutils.h
@@ -89,6 +89,7 @@ private:
 
     void INSTALLER_EXPORT mkdir(const QString &path);
     void INSTALLER_EXPORT mkpath(const QString &path);
+    bool INSTALLER_EXPORT createDirectoryWithParents(const QString &path);
 #ifdef Q_OS_MACOS
     void INSTALLER_EXPORT mkalias(const QString &path, const QString &alias);
 #endif