Properly fix #6369

Avoid that \newcommand[x] definitions of math macros are pushed multiple
times to the preview loader.

Redefinitions (via \renewcommand[x]) are properly handled.

lib/scripts/lyxpreview2bitmap.py

@@ -160,25 +160,18 @@ def extract_metrics_info(dvipng_stdout):
 
 def fix_latex_file(latex_file):
     documentclass_re = re.compile("(\\\\documentclass\[)(1[012]pt,?)(.+)")
-    newcommandx_re = re.compile("^(\\\\newcommandx)(.+)")
 
     tmp = mkstemp()
 
     changed = 0
     for line in open(latex_file, 'r').readlines():
         match = documentclass_re.match(line)
-        if match != None:
-            changed = 1
-            tmp.write("%s%s\n" % (match.group(1), match.group(3)))
-            continue
-
-        match = newcommandx_re.match(line)
         if match == None:
             tmp.write(line)
             continue
 
         changed = 1
-        tmp.write("\\providecommandx%s\n" % match.group(2))
+        tmp.write("%s%s\n" % (match.group(1), match.group(3)))
 
     if changed:
         copyfileobj(tmp, open(latex_file,"wb"), 1)

src/graphics/PreviewLoader.cpp

@@ -205,6 +205,10 @@ public:
 	void add(string const & latex_snippet);
 	///
 	void remove(string const & latex_snippet);
+	/// Record math macro definitions added to the loader
+	void addMacroDef(docstring const & latex_snippet);
+	/// Has a math macro definition already been added to the loader?
+	bool hasMacroDef(docstring const & latex_snippet) const;
 	/// \p wait whether to wait for the process to complete or, instead,
 	/// to do it in the background.
 	void startLoading(bool wait = false);
@@ -242,6 +246,9 @@ private:
 	 */
 	InProgressProcesses in_progress_;
 
+	///
+	set<docstring> macrodefs_;
+
 	///
 	PreviewLoader & parent_;
 	///
@@ -296,6 +303,18 @@ void PreviewLoader::remove(string const & latex_snippet) const
 }
 
 
+void PreviewLoader::addMacroDef(docstring const & latex_snippet) const
+{
+	pimpl_->addMacroDef(latex_snippet);
+}
+
+
+bool PreviewLoader::hasMacroDef(docstring const & latex_snippet) const
+{
+	return pimpl_->hasMacroDef(latex_snippet);
+}
+
+
 void PreviewLoader::startLoading(bool wait) const
 {
 	pimpl_->startLoading(wait);
@@ -532,6 +551,18 @@ void PreviewLoader::Impl::remove(string const & latex_snippet)
 }
 
 
+void PreviewLoader::Impl::addMacroDef(docstring const & latex_snippet)
+{
+	macrodefs_.insert(latex_snippet);
+}
+
+
+bool PreviewLoader::Impl::hasMacroDef(docstring const & latex_snippet) const
+{
+	return macrodefs_.find(latex_snippet) != macrodefs_.end();
+}
+
+
 void PreviewLoader::Impl::startLoading(bool wait)
 {
 	if (pending_.empty() || !pconverter_)

src/graphics/PreviewLoader.h

@@ -19,6 +19,7 @@
 #define PREVIEWLOADER_H
 
 #include <boost/signal.hpp>
+#include "support/docstring.h"
 
 #include "ColorCode.h"
 
@@ -65,6 +66,11 @@ public:
 	/// Remove this snippet of LaTeX from the PreviewLoader.
 	void remove(std::string const & latex_snippet) const;
 
+	/// Record math macro definitions added to the loader
+	void addMacroDef(docstring const & latex_snippet) const;
+	/// Has a math macro definition already been added to the loader?
+	bool hasMacroDef(docstring const & latex_snippet) const;
+
 	/** We have accumulated several latex snippets with status "InQueue".
 	 *  Initiate their transformation into bitmap images.
 	 */

src/insets/RenderPreview.cpp

@@ -257,6 +257,24 @@ void RenderPreview::removePreview(Buffer const & buffer)
 }
 
 
+void RenderPreview::addMacroDef(docstring const & latex_snippet,
+                               Buffer const & buffer)
+{
+	graphics::PreviewLoader * loader = buffer.loader();
+	LASSERT(loader, return);
+	loader->addMacroDef(latex_snippet);
+}
+
+
+bool RenderPreview::hasMacroDef(docstring const & latex_snippet,
+                               Buffer const & buffer)
+{
+	graphics::PreviewLoader * loader = buffer.loader();
+	LASSERT(loader, return false);
+	return loader->hasMacroDef(latex_snippet);
+}
+
+
 void RenderPreview::imageReady(graphics::PreviewImage const & pimage)
 {
 	// Check the current snippet is the same as that previewed.

src/insets/RenderPreview.h

@@ -74,6 +74,11 @@ public:
 			graphics::PreviewLoader & ploader,
 			bool ignore_lyxrc = false);
 
+	/// Record math macro definitions added to the preview loader
+	void addMacroDef(docstring const & latex_snippet, Buffer const & buffer);
+	/// Has a math macro definition already been added to the preview loader?
+	bool hasMacroDef(docstring const & latex_snippet, Buffer const & buffer);
+
 	/// Begin the loading process.
 	/// \param forexport : whether this is intended for export. if so,
 	/// then we ignore LyXRC and wait for the image to be generated.

src/mathed/InsetMathHull.cpp

@@ -637,12 +637,22 @@ void InsetMathHull::preparePreview(DocIterator const & pos,
 	buffer->listMacroNames(macros);
 	MacroNameSet::iterator it = macros.begin();
 	MacroNameSet::iterator end = macros.end();
-	odocstringstream macro_preamble;
+	docstring macro_preamble;
 	for (; it != end; ++it) {
 		MacroData const * data = buffer->getMacro(*it, pos, true);
 		if (data) {
-			data->write(macro_preamble, true);
+			odocstringstream mac_preamble;
-			macro_preamble << endl;
+			data->write(mac_preamble, false);
+			docstring const mps = mac_preamble.str();
+			bool const is_new_def = prefixIs(mps, from_ascii("\\newcomm"));
+			// assure that \newcommand definitions of macros are only added once
+			if (!is_new_def || !preview_->hasMacroDef(mps, *buffer)) {
+				if (is_new_def)
+					preview_->addMacroDef(mps, *buffer);
+				if (!macro_preamble.empty())
+					macro_preamble += '\n';
+				macro_preamble += mps;
+			}
 		}
 	}
 
@@ -667,8 +677,7 @@ void InsetMathHull::preparePreview(DocIterator const & pos,
 				          '{' + convert<docstring>(num) + '}';
 		}
 	}
-	docstring const snippet = macro_preamble.str() +
+	docstring const snippet = macro_preamble + setcnt + latexString(*this);
-	    setcnt + latexString(*this);
 	LYXERR(Debug::MACROS, "Preview snippet: " << snippet);
 	preview_->addPreview(snippet, *buffer, forexport);
 }