From 972ab453058ec7a9c9f0382cada67ba68283a930 Mon Sep 17 00:00:00 2001
From: baczus <baczusc60@gmail.com>
Date: Wed, 4 Sep 2019 20:57:43 +0200
Subject: [PATCH] Post-processing: Convert character encoding only when needed
 (#141)

---
 libqnapi/src/subtitlepostprocessor.cpp | 32 +++++++++++++++-----------
 libqnapi/src/subtitlepostprocessor.h   |  3 +--
 2 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/libqnapi/src/subtitlepostprocessor.cpp b/libqnapi/src/subtitlepostprocessor.cpp
index 0b27ccd..ced922c 100644
--- a/libqnapi/src/subtitlepostprocessor.cpp
+++ b/libqnapi/src/subtitlepostprocessor.cpp
@@ -26,6 +26,8 @@ SubtitlePostProcessor::SubtitlePostProcessor(
 
 void SubtitlePostProcessor::perform(const QString& movieFilePath,
                                     const QString& subtitleFilePath) const {
+  if (!QFileInfo(subtitleFilePath).exists()) return;
+
   if (ppConfig.removeLines()) {
     ppRemoveLinesContainingWords(subtitleFilePath, ppConfig.removeLinesWords());
   }
@@ -35,11 +37,9 @@ void SubtitlePostProcessor::perform(const QString& movieFilePath,
       ppReplaceDiacriticsWithASCII(subtitleFilePath);
       break;
     case ECM_CHANGE:
-      if (!ppConfig.encodingAutoDetectFrom() ||
-          !ppChangeSubtitlesEncoding(subtitleFilePath, ppConfig.encodingTo())) {
-        ppChangeSubtitlesEncoding(subtitleFilePath, ppConfig.encodingFrom(),
+        ppChangeSubtitlesEncoding(subtitleFilePath,
+                                  ppDetermineEncodingFrom(subtitleFilePath),
                                   ppConfig.encodingTo());
-      }
       break;
     case ECM_ORIGINAL:
       // Nie ruszaj pobranych napisów!
@@ -55,7 +55,6 @@ void SubtitlePostProcessor::perform(const QString& movieFilePath,
 
 bool SubtitlePostProcessor::ppReplaceDiacriticsWithASCII(
     const QString& subtitleFilePath) const {
-  if (!QFileInfo(subtitleFilePath).exists()) return false;
 
   QString from = encodingUtils.detectFileEncoding(subtitleFilePath);
 
@@ -84,6 +83,12 @@ bool SubtitlePostProcessor::ppReplaceDiacriticsWithASCII(
 bool SubtitlePostProcessor::ppChangeSubtitlesEncoding(
     const QString& subtitleFilePath, const QString& from,
     const QString& to) const {
+
+  if (QString::compare(from, ppConfig.encodingTo(), Qt::CaseInsensitive) == 0) {
+      // The same encoding, conversion isn't required.
+      return false;
+  }
+
   QFile f(subtitleFilePath);
   if (!f.open(QIODevice::ReadOnly)) return false;
 
@@ -109,20 +114,19 @@ bool SubtitlePostProcessor::ppChangeSubtitlesEncoding(
   return true;
 }
 
-bool SubtitlePostProcessor::ppChangeSubtitlesEncoding(
-    const QString& subtitleFilePath, const QString& to) const {
-  if (!QFileInfo(subtitleFilePath).exists()) return false;
-
-  QString from = encodingUtils.detectFileEncoding(subtitleFilePath);
-
-  if (from.isEmpty()) return false;
+QString SubtitlePostProcessor::ppDetermineEncodingFrom(const QString& subtitleFilePath) const {
+  if (ppConfig.encodingAutoDetectFrom()) {
+    QString autodetectedFrom = encodingUtils.detectFileEncoding(subtitleFilePath);
+    if (!autodetectedFrom.isEmpty()) {
+      return autodetectedFrom;
+    }
+  }
 
-  return ppChangeSubtitlesEncoding(from, to);
+  return ppConfig.encodingFrom();
 }
 
 bool SubtitlePostProcessor::ppRemoveLinesContainingWords(
     const QString& subtitleFilePath, QStringList wordList) const {
-  if (!QFileInfo(subtitleFilePath).exists()) return false;
 
   wordList = wordList.filter(QRegExp("^(.+)$"));
 
diff --git a/libqnapi/src/subtitlepostprocessor.h b/libqnapi/src/subtitlepostprocessor.h
index ef88dad..54857c3 100644
--- a/libqnapi/src/subtitlepostprocessor.h
+++ b/libqnapi/src/subtitlepostprocessor.h
@@ -35,8 +35,7 @@ class SubtitlePostProcessor {
   bool ppReplaceDiacriticsWithASCII(const QString& subtitleFilePath) const;
   bool ppChangeSubtitlesEncoding(const QString& subtitleFilePath,
                                  const QString& from, const QString& to) const;
-  bool ppChangeSubtitlesEncoding(const QString& subtitleFilePath,
-                                 const QString& to) const;
+  QString ppDetermineEncodingFrom(const QString& subtitleFilePath) const;
   bool ppRemoveLinesContainingWords(const QString& subtitleFilePath,
                                     QStringList wordList) const;