Fix pasting insets into math (bug #9302)

The problem was that the conversion to plain text (which is used as an
intermediate step) requires for some insets a valid buffer pointer, but
insets in the cut stack do not have one. Now we use the same temp buffer
business as for copying to the external clipboard.

src/CutAndPaste.cpp

@@ -480,8 +480,7 @@ PitPosPair eraseSelectionHelper(BufferParams const & params,
 }
 
 
-void putClipboard(ParagraphList const & paragraphs, 
+Buffer * copyToTempBuffer(ParagraphList const & paragraphs, DocumentClassConstPtr docclass)
-	DocumentClassConstPtr docclass, docstring const & plaintext)
 {
 	// This used to need to be static to avoid a memory leak. It no longer needs
 	// to be so, but the alternative is to construct a new one of these (with a
@@ -500,7 +499,7 @@ void putClipboard(ParagraphList const & paragraphs,
 	// Use a clone for the complicated stuff so that we do not need to clean
 	// up in order to avoid a crash.
 	Buffer * buffer = staticbuffer->cloneBufferOnly();
-	LASSERT(buffer, return);
+	LASSERT(buffer, return 0);
 
 	// This needs doing every time.
 	// Since setDocumentClass() causes deletion of the old document class
@@ -522,6 +521,17 @@ void putClipboard(ParagraphList const & paragraphs,
 	ErrorList el;
 	pasteSelectionHelper(dit, paragraphs, docclass, buffer, el);
 
+	return buffer;
+}
+
+
+void putClipboard(ParagraphList const & paragraphs, 
+	DocumentClassConstPtr docclass, docstring const & plaintext)
+{
+	Buffer * buffer = copyToTempBuffer(paragraphs, docclass);
+	if (!buffer) // already asserted in copyToTempBuffer()
+		return;
+
 	// We don't want to produce images that are not used. Therefore,
 	// output formulas as MathML. Even if this is not understood by all
 	// applications, the number that can parse it should go up in the future.
@@ -1051,11 +1061,16 @@ void clearCutStack()
 }
 
 
-docstring selection(size_t sel_index)
+docstring selection(size_t sel_index, DocumentClassConstPtr docclass)
 {
-	return sel_index < theCuts.size()
+	if (sel_index >= theCuts.size())
-		? theCuts[sel_index].first.back().asString(AS_STR_INSETS | AS_STR_NEWLINES)
+		return docstring();
-		: docstring();
+
+	boost::scoped_ptr<Buffer> buffer(copyToTempBuffer(theCuts[sel_index].first, docclass));
+	if (!buffer)
+		return docstring();
+
+	return buffer->paragraphs().back().asString(AS_STR_INSETS | AS_STR_NEWLINES);
 }
 
 

src/CutAndPaste.h

@@ -39,7 +39,7 @@ std::vector<docstring> availableSelections(Buffer const *);
 /// Get the number of available elements in the cut buffer.
 size_type numberOfSelections();
 /// Get the sel_index-th element of the cut buffer in plain text format.
-docstring selection(size_t sel_index);
+docstring selection(size_t sel_index, DocumentClassConstPtr docclass);
 
 /**
  * Replace using the font of the first selected character and select

src/mathed/InsetMathGrid.cpp

@@ -20,6 +20,7 @@
 #include "MetricsInfo.h"
 
 #include "Buffer.h"
+#include "BufferParams.h"
 #include "BufferView.h"
 #include "CutAndPaste.h"
 #include "FuncStatus.h"
@@ -1339,7 +1340,7 @@ void InsetMathGrid::doDispatch(Cursor & cur, FuncRequest & cmd)
 			idocstringstream is(cmd.argument());
 			int n = 0;
 			is >> n;
-			topaste = cap::selection(n);
+			topaste = cap::selection(n, buffer().params().documentClassPtr());
 		}
 		InsetMathGrid grid(buffer_, 1, 1);
 		if (!topaste.empty())

src/mathed/InsetMathNest.cpp

@@ -40,6 +40,7 @@
 
 #include "Bidi.h"
 #include "Buffer.h"
+#include "BufferParams.h"
 #include "BufferView.h"
 #include "CoordCache.h"
 #include "Cursor.h"
@@ -583,7 +584,7 @@ void InsetMathNest::doDispatch(Cursor & cur, FuncRequest & cmd)
 			size_t n = 0;
 			idocstringstream is(cmd.argument());
 			is >> n;
-			topaste = cap::selection(n);
+			topaste = cap::selection(n, buffer().params().documentClassPtr());
 		}
 		cur.niceInsert(topaste, parseflg, false);
 		cur.clearSelection(); // bug 393