From 76f49fad78db5ed768db163feef4e3b3c062228f Mon Sep 17 00:00:00 2001
From: Juergen Spitzmueller <spitz@lyx.org>
Date: Mon, 23 Oct 2017 08:20:58 +0200
Subject: [PATCH] Implement ParamInfo::HANDLING_LTRIM and use it to ltrim
 InsetBibitem output

See #9847.
---
 src/insets/InsetBibitem.cpp       |  3 ++-
 src/insets/InsetCommandParams.cpp | 27 ++++++++++++++++-----------
 src/insets/InsetCommandParams.h   |  7 ++++---
 3 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/src/insets/InsetBibitem.cpp b/src/insets/InsetBibitem.cpp
index d5ebaf7640..08e8c76665 100644
--- a/src/insets/InsetBibitem.cpp
+++ b/src/insets/InsetBibitem.cpp
@@ -112,7 +112,8 @@ ParamInfo const & InsetBibitem::findInfo(string const & /* cmdName */)
 		param_info_.add("label", ParamInfo::LATEX_OPTIONAL,
 				ParamInfo::HANDLING_LATEXIFY);
 		param_info_.add("key", ParamInfo::LATEX_REQUIRED,
-				ParamInfo::HANDLING_ESCAPE);
+				ParamInfo::ParamHandling(ParamInfo::HANDLING_ESCAPE
+							 | ParamInfo::HANDLING_LTRIM));
 		param_info_.add("literal", ParamInfo::LYX_INTERNAL);
 	}
 	return param_info_;
diff --git a/src/insets/InsetCommandParams.cpp b/src/insets/InsetCommandParams.cpp
index 9d34808d41..aa2458ce87 100644
--- a/src/insets/InsetCommandParams.cpp
+++ b/src/insets/InsetCommandParams.cpp
@@ -432,12 +432,21 @@ docstring InsetCommandParams::prepareCommand(OutputParams const & runparams,
 					     docstring const & command,
 					     ParamInfo::ParamHandling handling) const
 {
-	if (handling == ParamInfo::HANDLING_LATEXIFY)
+	docstring result;
+	bool ltrimmed = false;
+	// Trimming can be done on top of any of the other handlings
+	// We check this here since handling might be changed below.
+	if (handling & ParamInfo::HANDLING_LTRIM) {
+		// this is used if no other handling is done
+		result = command;
+		ltrimmed = true;
+	}
+	if (handling & ParamInfo::HANDLING_LATEXIFY)
 		if ((*this)["literal"] == "true")
 			handling = ParamInfo::HANDLING_NONE;
-	docstring result;
-	switch (handling) {
-	case ParamInfo::HANDLING_LATEXIFY: {
+
+	// LATEXIFY, ESCAPE and NONE are mutually exclusive
+	if (handling & ParamInfo::HANDLING_LATEXIFY) {
 		// First handle backslash
 		result = subst(command, from_ascii("\\"), from_ascii("\\textbackslash{}"));
 		// Then get LaTeX macros
@@ -476,17 +485,13 @@ docstring InsetCommandParams::prepareCommand(OutputParams const & runparams,
 							result.replace(pos, 1, backslash + chars_escape[k] + term);
 				}
 		}
-		break;
 	}
-	case ParamInfo::HANDLING_ESCAPE:
+	else if (handling & ParamInfo::HANDLING_ESCAPE)
 		result = escape(command);
-		break;
-	case ParamInfo::HANDLING_NONE:
+	else if (handling & ParamInfo::HANDLING_NONE)
 		result = command;
-		break;
-	} // switch
 
-	return result;
+	return ltrimmed ? ltrim(result) : result;
 }
 
 
diff --git a/src/insets/InsetCommandParams.h b/src/insets/InsetCommandParams.h
index 121fdac176..e82320583f 100644
--- a/src/insets/InsetCommandParams.h
+++ b/src/insets/InsetCommandParams.h
@@ -42,9 +42,10 @@ public:
 	};
 	/// Special handling on output
 	enum ParamHandling {
-		HANDLING_NONE,    /// no special handling
-		HANDLING_ESCAPE,  /// escape special characters
-		HANDLING_LATEXIFY /// transform special characters to LaTeX macros
+		HANDLING_NONE = 1,    /// no special handling
+		HANDLING_ESCAPE = 2,  /// escape special characters
+		HANDLING_LATEXIFY = 4, /// transform special characters to LaTeX macros
+		HANDLING_LTRIM = 8 /// trim blanks on the left
 	};
 	///
 	class ParamData {