fix bug 2758:

* src/Paragraph.cpp:
	- make sure removed bibitems (inside a par) are restored correctly
	  (in pos 0).
* src/Text.{cpp,h} (handleBibitems):
	- new member, used by erase and backspace.
* src/Text3.cpp (getStatus):
	- allow inserting of bibitems only in pos 0.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@18304 a592a061-630c-0410-9148-cb99ea01b6c8

src/Paragraph.cpp

@@ -2603,12 +2603,34 @@ bool Paragraph::checkBiblio(bool track_changes)
 		&& getChar(0) == Paragraph::META_INSET
 		&& insetlist.begin()->inset->lyxCode() == Inset::BIBITEM_CODE;
 
+	docstring oldkey;
+	docstring oldlabel;
+
+	// remove bibitems in pos != 0
+	// restore them later in pos 0 if necessary
+	// (e.g. if a user inserts contents _before_ the item)
+	InsetList::const_iterator it = insetlist.begin();
+	InsetList::const_iterator end = insetlist.end();
+	for (; it != end; ++it)
+		if (it->inset->lyxCode() == Inset::BIBITEM_CODE
+		    && it->pos > 0) {
+			InsetBibitem * olditem = static_cast<InsetBibitem *>(it->inset);
+			oldkey = olditem->getParam("key");
+			oldlabel = olditem->getParam("label");
+			eraseChar(it->pos, track_changes);
+	}
+
 	if (hasbibitem)
 		return false;
 
 	InsetBibitem * inset(new InsetBibitem(InsetCommandParams("bibitem")));
+	// restore values of previously deleted item in this par.
+	if (!oldkey.empty())
+		inset->setParam("key", oldkey);
+	if (!oldlabel.empty())
+		inset->setParam("label", oldlabel);
 	insertInset(0, static_cast<Inset *>(inset),
-		Change(track_changes ? Change::INSERTED : Change::UNCHANGED));
+		    Change(track_changes ? Change::INSERTED : Change::UNCHANGED));
 
 	return true;
 }

src/Text.cpp

@@ -1170,6 +1170,38 @@ void Text::changeCase(Cursor & cur, Text::TextCase action)
 }
 
 
+bool Text::handleBibitems(Cursor & cur)
+{
+	if (cur.paragraph().layout()->labeltype != LABEL_BIBLIO)
+		return false;
+	// if a bibitem is deleted, merge with previous paragraph
+	// if this is a bibliography item as well
+	if (cur.pos() == 0) {
+		BufferParams const & bufparams = cur.buffer().params();
+		Paragraph const & par = cur.paragraph();
+		Cursor prevcur = cur;
+		if (cur.pit() > 0) {
+			--prevcur.pit();
+			prevcur.pos() = prevcur.lastpos();
+		}
+		Paragraph const & prevpar = prevcur.paragraph();
+		if (cur.pit() > 0 && par.layout() == prevpar.layout()) {
+			recordUndo(cur, Undo::ATOMIC, prevcur.pit());
+			mergeParagraph(bufparams, cur.text()->paragraphs(),
+				       prevcur.pit());
+			updateLabels(cur.buffer());
+			setCursorIntern(cur, prevcur.pit(), prevcur.pos());
+			cur.updateFlags(Update::Force);
+		// if not, reset the paragraph to default
+		} else
+			cur.paragraph().layout(
+				bufparams.getTextClass().defaultLayout());
+		return true;
+	}
+	return false;
+}
+
+
 bool Text::erase(Cursor & cur)
 {
 	BOOST_ASSERT(this == cur.text());
@@ -1200,6 +1232,8 @@ bool Text::erase(Cursor & cur)
 		}
 	}
 
+	needsUpdate |= handleBibitems(cur);
+
 	if (needsUpdate) {
 		// Make sure the cursor is correct. Is this really needed?
 		// No, not really... at least not here!
@@ -1298,6 +1332,8 @@ bool Text::backspace(Cursor & cur)
 	if (cur.pos() == cur.lastpos())
 		setCurrentFont(cur);
 
+	needsUpdate |= handleBibitems(cur);
+
 	// A singlePar update is not enough in this case.
 //		cur.updateFlags(Update::Force);
 	setCursor(cur.top(), cur.pit(), cur.pos());

src/Text.h

@@ -387,6 +387,8 @@ private:
 	// At cursor position 0, try to merge the paragraph with the one before it.
 	// Ignore change tracking, i.e., physically remove the end-of-par character
 	bool backspacePos0(Cursor & cur);
+	/// handle the case where bibitems were deleted
+	bool handleBibitems(Cursor & cur);
 
 	///
 	void deleteWordForward(Cursor & cur);

src/Text3.cpp

@@ -1654,7 +1654,8 @@ bool Text::getStatus(Cursor & cur, FuncRequest const & cmd,
 		return true;
 
 	case LFUN_BIBITEM_INSERT:
-		enable = (cur.paragraph().layout()->labeltype == LABEL_BIBLIO);
+		enable = (cur.paragraph().layout()->labeltype == LABEL_BIBLIO
+			  && cur.pos() == 0);
 		break;
 
 	case LFUN_DIALOG_SHOW_NEW_INSET: