[LyX/master] XML: use the new mechanisms for CR detection with errors.

[Thibaut Cuvelier]

commit bfc67c59b44415f2dea7ad068a8ac86e2b19f488
Author: Thibaut Cuvelier <tcuvelier at lyx.org>
Date:   Sat Aug 29 02:43:30 2020 +0200

    XML: use the new mechanisms for CR detection with errors.
    
    This helps tracking down line problems even in the presence of errors.
---
 src/xml.cpp |   12 ++++++++----
 src/xml.h   |    8 ++++++--
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/xml.cpp b/src/xml.cpp
index b4004af..2f49667 100644
--- a/src/xml.cpp
+++ b/src/xml.cpp
@@ -167,17 +167,21 @@ bool FontTag::operator==(StartTag const & tag) const
 } // namespace xml
 
 
-void XMLStream::writeError(std::string const &s) const
+void XMLStream::writeError(std::string const &s)
 {
 	LYXERR0(s);
-	os_ << from_utf8("<!-- Output Error: " + s + " -->\n");
+	*this << ESCAPE_NONE << from_utf8("<!-- Output Error: " + s + " -->");
+	*this << xml::CR();
 }
 
 
-void XMLStream::writeError(docstring const &s) const
+void XMLStream::writeError(docstring const &s)
 {
 	LYXERR0(s);
-	os_ << from_utf8("<!-- Output Error: ") << s << from_utf8(" -->\n");
+	*this << ESCAPE_NONE << from_utf8("<!-- Output Error: ");
+	*this << s;
+	*this << ESCAPE_NONE << from_utf8(" -->");
+	*this << xml::CR();
 }
 
 
diff --git a/src/xml.h b/src/xml.h
index 9a7cf17..45c62ab 100644
--- a/src/xml.h
+++ b/src/xml.h
@@ -103,9 +103,13 @@ public:
 	/// that simplifies the logic using this code.
 	bool isLastTagCR() const { return is_last_tag_cr_; };
 	///
-	void writeError(std::string const &) const;
+	void writeError(std::string const &);
 	///
-	void writeError(docstring const &) const;
+	void writeError(docstring const &);
+	///
+	typedef std::shared_ptr<xml::StartTag> TagPtr;
+	/// Returns the last element on the tag stack. XMLStream keeps ownership of the item.
+	TagPtr getLastStackTag();
 private:
 	///
 	void clearTagDeque();