This is the custom stream for XHTML output. It isn't used yet, and

lots of things that will be replaced have been left, so as not to
prevent compilation.

The point of this is that we need a good way to manage the nesting of tags,
that is, to make sure tags are properly nested. So everything here is pretty
trivial, except for XHTMLStream << EndTag.



git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@32083 a592a061-630c-0410-9148-cb99ea01b6c8

src/output_xhtml.cpp

@@ -31,7 +31,6 @@
 #include "support/debug.h"
 #include "support/lstrings.h"
 
-#include <boost/next_prior.hpp>
 #include <vector>
 
 using namespace std;
@@ -75,6 +74,251 @@ docstring htmlize(docstring const & str) {
 	return d.str();
 }
 
+
+bool isFontTag(string const & s)
+{
+	return s == "em" || s == "strong"; // others?
+}
+
+
+////////////////////////////////////////////////////////////////
+///
+/// XHTMLStream
+///
+////////////////////////////////////////////////////////////////
+
+XHTMLStream::XHTMLStream(odocstream & os) 
+		:os_(os)
+{}
+
+
+void XHTMLStream::cr() 
+{
+	// tabs?
+	os_ << std::endl;
+}
+
+
+bool XHTMLStream::closeFontTags()
+{
+	// first, we close any open font tags we can close
+	StartTag curtag = tag_stack_.back();
+	while (isFontTag(curtag.tag_)) {
+		os_ << "</" << curtag.tag_ << ">";
+		tag_stack_.pop_back();
+		if (tag_stack_.empty())
+			// this probably shouldn't happen, since then the
+			// font tags weren't in any other tag. but that
+			// problem will likely be caught elsewhere.
+			return true;
+		curtag = tag_stack_.back();
+	}
+	// so we've hit a non-font tag. let's see if any of the
+	// remaining tags are font tags.
+	TagStack::const_iterator it = tag_stack_.begin();
+	TagStack::const_iterator en = tag_stack_.end();
+	bool noFontTags = true;
+	for (; it != en; ++it) {
+		if (isFontTag(it->tag_)) {
+			LYXERR0("Font tag `" << it->tag_ << "' still open in closeFontTags().");
+			noFontTags = false;
+		}
+	}
+	return noFontTags;
+}
+
+
+void XHTMLStream::clearTagDeque()
+{
+	while (!pending_tags_.empty()) {
+		StartTag const & tag = pending_tags_.front();
+		// tabs?
+		os_ << "<" << tag.tag_ << " " << tag.attr_ << ">";
+		tag_stack_.push_back(tag);
+		pending_tags_.pop_front();
+	}
+}
+
+XHTMLStream & XHTMLStream::operator<<(docstring const & d)
+{
+	// I'm tempted to make sure here that there are no tags in the input
+	clearTagDeque();
+	os_ << htmlize(d);
+	return *this;
+}
+
+
+/*
+XHTMLStream & XHTMLStream::operator<<(char_type c)
+{
+	clearTagDeque();
+	os_ << escapeChar(c);
+	return *this;
+}
+*/
+
+
+XHTMLStream & XHTMLStream::operator<<(StartTag const & tag) 
+{
+	pending_tags_.push_back(tag);
+	if (tag.keepempty_)
+		clearTagDeque();
+	return *this;
+}
+
+
+XHTMLStream & XHTMLStream::operator<<(CompTag const & tag) 
+{
+	clearTagDeque();
+	// tabs?
+	os_ << "<" << tag.tag_ << " " << tag.attr_ << " />";
+	return *this;
+}
+
+
+bool	XHTMLStream::isTagOpen(string const & stag)
+{
+	TagStack::const_iterator sit = tag_stack_.begin();
+	TagStack::const_iterator const sen = tag_stack_.end();
+	for (; sit != sen; ++sit)
+		// we could check for the
+		if (sit->tag_ == stag) 
+			return true;
+	return false;
+}
+
+
+// this is complicated, because we want to make sure that
+// everything is properly nested. the code ought to make 
+// sure of that, but we won't assert (yet) if we run into
+// a problem. we'll just output error messages and try our
+// best to make things work.
+XHTMLStream & XHTMLStream::operator<<(EndTag const & etag)
+{
+	// first make sure we're not closing an empty tag
+	if (!pending_tags_.empty()) {
+		StartTag const & stag = pending_tags_.back();
+		if (etag.tag_ == stag.tag_)  {
+			// we have <tag></tag>, so we discard it and remove it 
+			// from the pending_tags_.
+			pending_tags_.pop_back();
+			return *this;
+		}
+		// there is a pending tag that isn't the one we are trying
+		// to close. 
+		// is this tag itself pending?
+		// non-const iterators because we may call erase().
+		TagDeque::iterator dit = pending_tags_.begin();
+		TagDeque::iterator const den = pending_tags_.end();
+		for (; dit != den; ++dit) {
+			if (dit->tag_ == etag.tag_) {
+				// it was pending, so we just erase it
+				LYXERR0("Tried to close pending tag `" << etag.tag_ 
+				        << "' when other tags were pending. Tag discarded.");
+				pending_tags_.erase(dit);
+				return *this;
+			}
+		}
+		// so etag isn't itself pending. is it even open?
+		if (!isTagOpen(etag.tag_)) {
+			LYXERR0("Tried to close `" << etag.tag_ 
+			         << "' when tag was not open. Tag discarded.");
+			return *this;
+		}
+		// ok, so etag is open.
+		// our strategy will be as below: we will do what we need to 
+		// do to close this tag.
+		LYXERR0("Closing tag `" << etag.tag_ 
+		        << "' when other tags are pending. Discarded pending tags:");
+		for (dit = pending_tags_.begin(); dit != den; ++dit)
+			LYXERR0(dit->tag_);
+		// clear the pending tags...
+		pending_tags_.clear();
+		// ...and then just fall through.
+	}
+
+	// is the tag we are closing the last one we opened?
+	if (etag.tag_ == tag_stack_.back().tag_) {
+		// output it...
+		os_ << "</" << etag.tag_ << ">";
+		// ...and forget about it
+		tag_stack_.pop_back();
+		return *this;
+	} 
+	
+	// we are trying to close a tag other than the one last opened. 
+	// let's first see if this particular tag is still open somehow.
+	if (!isTagOpen(etag.tag_)) {
+		LYXERR0("Tried to close `" << etag.tag_ 
+		        << "' when tag was not open. Tag discarded.");
+		return *this;
+	}
+	
+	// so the tag was opened, but other tags have been opened since
+	// and not yet closed.
+	// if it's a font tag, though...
+	if (isFontTag(etag.tag_)) {
+		// it won't be a problem if the other tags open since this one
+		// are also font tags.
+		TagStack::const_reverse_iterator rit = tag_stack_.rbegin();
+		TagStack::const_reverse_iterator ren = tag_stack_.rend();
+		for (; rit != ren; ++rit) {
+			if (!isFontTag(rit->tag_)) {
+				// we'll just leave it and, presumably, have to close it later.
+				LYXERR0("Unable to close font tag `" << etag.tag_ 
+				        << "' due to open non-font tags.");
+				return *this;
+			}
+		}
+		
+		// so we have e.g.:
+		//    <em>this is <strong>bold
+		// and are being asked to closed em. we want:
+		//    <em>this is <strong>bold</strong></em><strong>
+		// first, we close the intervening tags...
+		StartTag curtag = tag_stack_.back();
+		// ...remembering them in a stack.
+		TagStack fontstack;
+		while (curtag.tag_ != etag.tag_) {
+			os_ << "</" << curtag.tag_ << ">";
+			fontstack.push_back(curtag);
+			tag_stack_.pop_back();
+			curtag = tag_stack_.back();
+		}
+		// now close our tag...
+		os_ << "</" << etag.tag_ << ">";
+		// ...and restore the other tags.
+		rit = fontstack.rbegin();
+		ren = fontstack.rend();
+		for (; rit != ren; ++rit)
+			pending_tags_.push_back(*rit);
+		return *this;
+	}
+	
+	// it wasn't a font tag.
+	// so other tags were opened before this one and not properly closed. 
+	// so we'll close them, too. that may cause other issues later, but it 
+	// at least guarantees proper nesting.
+	LYXERR0("Closing tag `" << etag.tag_ 
+	        << "' when other tags are open, namely:");
+	StartTag curtag = tag_stack_.back();
+	while (curtag.tag_ != etag.tag_) {
+		LYXERR0(curtag.tag_);
+		os_ << "</" << curtag.tag_ << ">";
+		tag_stack_.pop_back();
+		curtag = tag_stack_.back();
+	}
+	// curtag is now the one we actually want.
+	os_ << "</" << curtag.tag_ << ">";
+	tag_stack_.pop_back();
+	
+	return *this;
+}
+
+
+///////////////////////////////////////////////////////////////
+// OLD STUFF to be replaced
+
 // FIXME This needs to be protected somehow.
 static vector<string> taglist;
 
@@ -148,6 +392,9 @@ bool closeItemTag(odocstream & os, Layout const & lay)
 	return html::closeTag(os, lay.htmlitemtag());
 }
 
+// end of old stuff to be replaced
+///////////////////////////////////////////////////////////////
+
 ParagraphList::const_iterator searchParagraphHtml(
 	ParagraphList::const_iterator p,
 	ParagraphList::const_iterator const & pend)

src/output_xhtml.h

@@ -12,7 +12,10 @@
 #ifndef OUTPUT_XHTML_H
 #define OUTPUT_XHTML_H
 
-#include "support/strfwd.h"
+#include "support/docstream.h"
+
+#include <deque>
+#include <vector>
 
 namespace lyx {
 
@@ -27,15 +30,95 @@ void xhtmlParagraphs(Text const & text,
 		       OutputParams const & runparams);
 
 namespace html {
+struct StartTag {
 	///
-	docstring escapeChar(char_type c);
-	/// converts a string to a form safe for links, etc
-	docstring htmlize(docstring const & str);
-	/// \return true if tag was opened, false if not 
-	bool openTag(odocstream & os, std::string const & tag, 
-	             std::string const & attr);
-	/// \return true if tag was opened, false if not 
-	bool closeTag(odocstream & os, std::string const & tag);
+	StartTag(std::string const & tag, std::string const & attr, 
+		bool keepempty = false) 
+		: tag_(tag), attr_(attr), keepempty_(keepempty) {}
+	///
+	std::string tag_;
+	///
+	std::string attr_;
+	/// whether to keep things like "<tag></tag>" or discard them
+	/// you would want this for td, e.g, but maybe not for a div
+	bool keepempty_;
+};
+
+
+struct EndTag {
+	///
+	EndTag(std::string tag) : tag_(tag) {}
+	///
+	std::string tag_;
+};
+
+
+// Tags like <img />
+struct CompTag {
+	///
+	CompTag(std::string const & tag, std::string const & attr)
+		: tag_(tag), attr_(attr) {}
+	///
+	std::string tag_;
+	///
+	std::string attr_;
+};
+
+
+class XHTMLStream {
+public:
+	///
+	explicit XHTMLStream(odocstream & os);
+	///
+	void cr();
+	///
+	odocstream & os() { return os_; }
+	///
+	// int & tab() { return tab_; }
+	/// closes any font tags that are eligible to be closed,
+	/// i.e., last on the tag_stack_.
+	/// \return false if there are open font tags we could not close.
+	/// because they are "blocked" by open non-font tags on the stack.
+	bool closeFontTags();
+	///
+	XHTMLStream & operator<<(docstring const &);
+	///
+	//XHTMLStream & operator<<(char_type);
+	///
+	XHTMLStream & operator<<(StartTag const &);
+	///
+	XHTMLStream & operator<<(EndTag const &);
+	///
+	XHTMLStream & operator<<(CompTag const &);
+private:
+	///
+	void clearTagDeque();
+	///
+	bool isTagOpen(std::string const &);
+	///
+	odocstream & os_;
+	///
+	// int tab_;
+	///
+	typedef std::deque<StartTag> TagDeque;
+	///
+	typedef std::vector<StartTag> TagStack;
+	/// holds start tags until we know there is content in them.
+	TagDeque pending_tags_;
+	/// remembers the history, so we can make sure we nest properly.
+	TagStack tag_stack_;
+};
+
+
+///
+docstring escapeChar(char_type c);
+/// converts a string to a form safe for links, etc
+docstring htmlize(docstring const & str);
+/// \return true if tag was opened, false if not 
+bool openTag(odocstream & os, std::string const & tag, 
+						 std::string const & attr);
+/// \return true if tag was opened, false if not 
+bool closeTag(odocstream & os, std::string const & tag);
 }
 } // namespace lyx