More places where DocumentClassPtr should not be copied

Spotted by COverity scan.

src/CutAndPaste.cpp

@@ -126,7 +126,7 @@ static bool isFullyDeleted(ParagraphList const & pars)
 
 PasteReturnValue
 pasteSelectionHelper(DocIterator const & cur, ParagraphList const & parlist,
-                     DocumentClassConstPtr oldDocClass, cap::BranchAction branchAction,
+                     DocumentClassConstPtr const & oldDocClass, cap::BranchAction branchAction,
                      ErrorList & errorlist)
 {
 	Buffer const & buffer = *cur.buffer();
@@ -229,7 +229,7 @@ pasteSelectionHelper(DocIterator const & cur, ParagraphList const & parlist,
 	}
 
 	// set the paragraphs to plain layout if necessary
-	DocumentClassConstPtr newDocClass = buffer.params().documentClassPtr();
+	DocumentClassConstPtr const & newDocClass = buffer.params().documentClassPtr();
 	Layout const & plainLayout = newDocClass->plainLayout();
 	Layout const & defaultLayout = newDocClass->defaultLayout();
 	if (cur.inset().usePlainLayout()) {
@@ -699,7 +699,7 @@ void putClipboard(ParagraphList const & paragraphs,
 
 void copySelectionHelper(Buffer const & buf, Text const & text,
 	pit_type startpit, pit_type endpit,
-	int start, int end, DocumentClassConstPtr dc, CutStack & cutstack)
+	int start, int end, DocumentClassConstPtr const & dc, CutStack & cutstack)
 {
 	ParagraphList const & pars = text.paragraphs();
 
@@ -1245,7 +1245,7 @@ docstring selection(size_t sel_index, DocInfoPair docinfo, bool for_math)
 
 
 void pasteParagraphList(Cursor & cur, ParagraphList const & parlist,
-			DocumentClassConstPtr docclass, AuthorList const & authors,
+			DocumentClassConstPtr const & docclass, AuthorList const & authors,
 			ErrorList & errorList,
 			cap::BranchAction branchAction)
 {

src/CutAndPaste.h

@@ -128,7 +128,7 @@ enum BranchAction {
 /// Paste the paragraph list \p parlist at the position given by \p cur.
 /// Does not handle undo. Does only work in text, not mathed.
 void pasteParagraphList(Cursor & cur, ParagraphList const & parlist,
-			DocumentClassConstPtr textclass, AuthorList const & authors,
+			DocumentClassConstPtr const & textclass, AuthorList const & authors,
 			ErrorList & errorList,
 			BranchAction branchAction = BRANCH_ASK);
 

src/frontends/qt/GuiApplication.cpp

@@ -744,7 +744,7 @@ class SocketNotifier : public QSocketNotifier
 {
 public:
 	/// connect a connection notification from the LyXServerSocket
-	SocketNotifier(QObject * parent, int fd, Application::SocketCallback func)
+	SocketNotifier(QObject * parent, int fd, Application::SocketCallback const & func)
 		: QSocketNotifier(fd, QSocketNotifier::Read, parent), func_(func)
 	{}
 

src/support/ForkedCalls.cpp

@@ -290,7 +290,7 @@ int ForkedCall::startScript(Starttype wait, string const & what)
 }
 
 
-int ForkedCall::startScript(string const & what, sigPtr signal)
+int ForkedCall::startScript(string const & what, sigPtr const & signal)
 {
 	command_ = commandPrep(trim(what));
 	signal_  = signal;

src/support/ForkedCalls.h

@@ -177,7 +177,7 @@ public:
 	int startScript(Starttype, std::string const & what);
 
 	///
-	int startScript(std::string const & what, sigPtr ptr);
+	int startScript(std::string const & what, sigPtr const & ptr);
 
 private:
 	///