[LyX/master] Fixup 3dc54d4a: fix string encoding issues with Qt4

[Jean-Marc Lasgouttes]

commit 938463b5d6bad29dfe71490a58d6724c4cd573f7
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Thu Jun 20 11:22:53 2019 +0200

    Fixup 3dc54d4a: fix string encoding issues with Qt4
    
    The culprit here is the constructor QString(QByteArray const &): in
    Qt4, it would interpret the byte array as latin1, and in Qt5 as utf8.
    
    Therefore it is safer to use explicitly QString::fromUtf8 instead of
    this constructor.
    
    Several places where additionally simplified, in order to avoid some
    extra conversions.
---
 src/frontends/qt4/GuiLyXFiles.cpp |    2 +-
 src/frontends/qt4/GuiWorkArea.cpp |    8 +++-----
 src/support/lstrings.cpp          |    9 ++++-----
 3 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/src/frontends/qt4/GuiLyXFiles.cpp 
b/src/frontends/qt4/GuiLyXFiles.cpp
index 98c4341..6a59e6e 100644
--- a/src/frontends/qt4/GuiLyXFiles.cpp
+++ b/src/frontends/qt4/GuiLyXFiles.cpp
@@ -43,7 +43,7 @@ namespace {
 QString const guiString(QString in)
 {
        // recode specially encoded chars in file names (URL encoding and 
underbar)
-       return 
QString(QByteArray::fromPercentEncoding(in.toUtf8())).replace('_', ' ');
+       return 
QString::fromUtf8(QByteArray::fromPercentEncoding(in.toUtf8())).replace('_', ' 
');
 }
 
 } // namespace anon
diff --git a/src/frontends/qt4/GuiWorkArea.cpp 
b/src/frontends/qt4/GuiWorkArea.cpp
index 001056d..7955731 100644
--- a/src/frontends/qt4/GuiWorkArea.cpp
+++ b/src/frontends/qt4/GuiWorkArea.cpp
@@ -1872,11 +1872,9 @@ public:
                : tab_(tab)
        {
                // Recode URL encoded chars via fromPercentEncoding()
-               filename_ = (filename.extension() == "lyx") ?
-                       QString(QByteArray::fromPercentEncoding(
-                                       
toqstr(filename.onlyFileNameWithoutExt()).toUtf8()))
-                       : QString(QByteArray::fromPercentEncoding(
-                                         
toqstr(filename.onlyFileName()).toUtf8()));
+               string const fn = (filename.extension() == "lyx")
+                       ? filename.onlyFileNameWithoutExt() : 
filename.onlyFileName();
+               filename_ = 
QString::fromUtf8(QByteArray::fromPercentEncoding(fn.c_str()));
                postfix_ = toqstr(filename.absoluteFilePath()).
                        split("/", QString::SkipEmptyParts);
                postfix_.pop_back();
diff --git a/src/support/lstrings.cpp b/src/support/lstrings.cpp
index 84757b3..68eabd9 100644
--- a/src/support/lstrings.cpp
+++ b/src/support/lstrings.cpp
@@ -1453,16 +1453,15 @@ std::string formatFPNumber(double x)
 
 docstring to_percent_encoding(docstring const & in, docstring const & ex)
 {
-       QByteArray input = toqstr(in).toUtf8();
-       QByteArray excludes = toqstr(ex).toUtf8();
-       return qstring_to_ucs4(QString(input.toPercentEncoding(excludes)));
+       QByteArray input = to_utf8(in).c_str();
+       QByteArray excludes = to_utf8(ex).c_str();
+       return from_utf8(string(input.toPercentEncoding(excludes).data()));
 }
 
 
 string from_percent_encoding(string const & in)
 {
-       QByteArray input = toqstr(in).toUtf8();
-       return fromqstr(QString(QByteArray::fromPercentEncoding(input)));
+       return QByteArray::fromPercentEncoding(in.c_str()).data();
 }