ENH: Make DICOM database relocatable

Libs/Core/ctkCorePythonQtDecorators.h

@@ -26,6 +26,7 @@
 
 // CTK includes
 #include <ctkBooleanMapper.h>
+#include <ctkUtils.h>
 #include <ctkErrorLogContext.h>
 #include <ctkWorkflowStep.h>
 #include <ctkWorkflowTransitions.h>
@@ -234,10 +235,32 @@ public Q_SLOTS:
 
 };
 
+//-----------------------------------------------------------------------------
+class PythonQtWrapper_CTKCore : public QObject
+{
+  Q_OBJECT
+
+public Q_SLOTS:
+  QString static_ctkCoreUtils_absolutePathFromInternal(const QString& internalPath, const QString& basePath)
+    {
+    return ctk::absolutePathFromInternal(internalPath, basePath);
+    }
+
+  QString static_ctkCoreUtils_internalPathFromAbsolute(const QString& absolutePath, const QString& basePath)
+    {
+    return ctk::internalPathFromAbsolute(absolutePath, basePath);
+    }
+};
+
 //-----------------------------------------------------------------------------
 void initCTKCorePythonQtDecorators()
 {
   PythonQt::self()->addDecorators(new ctkCorePythonQtDecorators);
+
+  // PythonQt doesn't support wrapping a static function and adding it to the top-level
+  // ctk module. This exposes static functions from ctkCoreUtils as ctk.ctkCoreUtils.absolutePathFromInternal(), etc.
+  // Note that PythonQtWrapper_CTKCore installs itself as ctk.ctk but using that same module here would replace PythonQtWrapper_CTKCore.
+  PythonQt::self()->registerCPPClass("ctkCoreUtils", "", "CTKCore", PythonQtCreateObject<PythonQtWrapper_CTKCore>);
 }
 
 #endif

Libs/Core/ctkUtils.cpp

@@ -413,3 +413,53 @@ qint64 ctk::msecsTo(const QDateTime& t1, const QDateTime& t2)
   return static_cast<qint64>(utcT1.daysTo(utcT2)) * static_cast<qint64>(1000*3600*24)
       + static_cast<qint64>(utcT1.time().msecsTo(utcT2.time()));
 }
+
+//------------------------------------------------------------------------------
+QString ctk::absolutePathFromInternal(const QString& internalPath, const QString& basePath)
+{
+  if (internalPath.isEmpty())
+  {
+    return internalPath;
+  }
+  if (QFileInfo(internalPath).isRelative())
+  {
+    QDir baseDirectory(basePath);
+    return QDir::cleanPath(baseDirectory.filePath(internalPath));
+  }
+  else
+  {
+    return internalPath;
+  }
+}
+
+//------------------------------------------------------------------------------
+QString ctk::internalPathFromAbsolute(const QString& absolutePath, const QString& basePath)
+{
+  if (absolutePath.isEmpty())
+  {
+    return absolutePath;
+  }
+  // Make it a relative path if it is within the base folder
+  if (QFileInfo(absolutePath).isRelative())
+  {
+    // already relative path, return it as is
+    return absolutePath;
+  }
+  QString baseFolderClean = QDir::cleanPath(QDir::fromNativeSeparators(basePath));
+  QString absolutePathClean = QDir::cleanPath(QDir::fromNativeSeparators(absolutePath));
+#ifdef Q_OS_WIN32
+  Qt::CaseSensitivity sensitivity = Qt::CaseInsensitive;
+#else
+  Qt::CaseSensitivity sensitivity = Qt::CaseSensitive;
+#endif
+  if (absolutePathClean.startsWith(baseFolderClean, sensitivity))
+  {
+    // file is in the base folder, make it a relative path
+    // (remove size+1 to remove the leading forward slash)
+    return absolutePathClean.remove(0, baseFolderClean.size() + 1);
+  }
+  else
+  {
+    return absolutePath;
+  }
+}

Libs/Core/ctkUtils.h

@@ -168,6 +168,17 @@ QString CTK_CORE_EXPORT qtHandleToString(Qt::HANDLE handle);
 /// bumping the minimum required Qt version for CTK.
 qint64 CTK_CORE_EXPORT msecsTo(const QDateTime& t1, const QDateTime& t2);
 
+/// Get absolute path from an "internal" path. If internal path is already an absolute path
+/// then that is returned unchanged. If internal path is relative path then basePath is used
+/// as a basis (prepended to internalPath).
+QString CTK_CORE_EXPORT absolutePathFromInternal(const QString& internalPath, const QString& basePath);
+
+/// Get "internal" path from an absolute path. internalPath will be a relative path if
+/// absolutePath is within the basePath, otherwise interalPath will be the same as absolutePath.
+/// This is useful for paths/directories relative to a base folder, to make the data or application relocatable.
+/// Absolute path can be retrieved from an internal path using absolutePathFromInternal function.
+QString CTK_CORE_EXPORT internalPathFromAbsolute(const QString& absolutePath, const QString& basePath);
+
 }
 
 #endif