1 files changed, 33 insertions, 22 deletions

diff --git a/src/corelib/kernel/qtranslator.cpp b/src/corelib/kernel/qtranslator.cpp
index 794a4aaa0c..dad471c1b0 100644
--- a/src/corelib/kernel/qtranslator.cpp
+++ b/src/corelib/kernel/qtranslator.cpp
@@ -613,6 +613,13 @@ bool QTranslatorPrivate::do_load(const QString &realname, const QString &directo
     return false;
 }
 
+Q_NEVER_INLINE
+static bool is_readable_file(const QString &name)
+{
+    const QFileInfo fi(name);
+    return fi.isReadable() && fi.isFile();
+}
+
 static QString find_translation(const QLocale & locale,
                                 const QString & filename,
                                 const QString & prefix,
@@ -625,9 +632,11 @@ static QString find_translation(const QLocale & locale,
         if (!path.isEmpty() && !path.endsWith(QLatin1Char('/')))
             path += QLatin1Char('/');
     }
+    const QString suffixOrDotQM = suffix.isNull() ? QStringLiteral(".qm") : suffix;
 
-    QFileInfo fi;
     QString realname;
+    realname += path + filename + prefix; // using += in the hope for some reserve capacity
+    const int realNameBaseSize = realname.size();
     QStringList fuzzyLocales;
 
     // see http://www.unicode.org/reports/tr35/#LanguageMatching for inspiration
@@ -646,16 +655,15 @@ static QString find_translation(const QLocale & locale,
     foreach (QString localeName, languages) {
         localeName.replace(QLatin1Char('-'), QLatin1Char('_'));
 
-        realname = path + filename + prefix + localeName + (suffix.isNull() ? QLatin1String(".qm") : suffix);
-        fi.setFile(realname);
-        if (fi.isReadable() && fi.isFile())
+        realname += localeName + suffixOrDotQM;
+        if (is_readable_file(realname))
             return realname;
 
-        realname = path + filename + prefix + localeName;
-        fi.setFile(realname);
-        if (fi.isReadable() && fi.isFile())
+        realname.truncate(realNameBaseSize + localeName.size());
+        if (is_readable_file(realname))
             return realname;
 
+        realname.truncate(realNameBaseSize);
         fuzzyLocales.append(localeName);
     }
 
@@ -668,33 +676,36 @@ static QString find_translation(const QLocale & locale,
                 break;
             localeName.truncate(rightmost);
 
-            realname = path + filename + prefix + localeName + (suffix.isNull() ? QLatin1String(".qm") : suffix);
-            fi.setFile(realname);
-            if (fi.isReadable() && fi.isFile())
+            realname += localeName + suffixOrDotQM;
+            if (is_readable_file(realname))
                 return realname;
 
-            realname = path + filename + prefix + localeName;
-            fi.setFile(realname);
-            if (fi.isReadable() && fi.isFile())
+            realname.truncate(realNameBaseSize + localeName.size());
+            if (is_readable_file(realname))
                 return realname;
+
+            realname.truncate(realNameBaseSize);
         }
     }
 
+    const int realNameBaseSizeFallbacks = path.size() + filename.size();
+
+    // realname == path + filename + prefix;
     if (!suffix.isNull()) {
-        realname = path + filename + suffix;
-        fi.setFile(realname);
-        if (fi.isReadable() && fi.isFile())
+        realname.replace(realNameBaseSizeFallbacks, prefix.size(), suffix);
+        // realname == path + filename;
+        if (is_readable_file(realname))
             return realname;
+        realname.replace(realNameBaseSizeFallbacks, suffix.size(), prefix);
     }
 
-    realname = path + filename + prefix;
-    fi.setFile(realname);
-    if (fi.isReadable() && fi.isFile())
+    // realname == path + filename + prefix;
+    if (is_readable_file(realname))
         return realname;
 
-    realname = path + filename;
-    fi.setFile(realname);
-    if (fi.isReadable() && fi.isFile())
+    realname.truncate(realNameBaseSizeFallbacks);
+    // realname == path + filename;
+    if (is_readable_file(realname))
         return realname;
 
     return QString();