workaround for Qt bug in contentsChange signal params, see https://bu…

…greports.qt.io/browse/QTBUG-49062

MSVC.md

@@ -16,7 +16,7 @@ or download in ZIP and extract to **D:\TBuild\**, rename **tdesktop-master** to
 
 ####OpenSSL
 
-Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **\\Program Files (x86)\\Microsoft Visual Studio 14.0\\Common7\\Tools\\Shortcuts\\** folder), go to **D:\\TBuild\\Libraries** and run
+Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **Start Menu > Programs > Visual Studio 2015** menu folder), go to **D:\\TBuild\\Libraries** and run
 
     git clone https://github.com/openssl/openssl.git
     cd openssl
@@ -89,7 +89,7 @@ or download in ZIP and extract to **D:\TBuild\Libraries\**, rename **libexif-0.6
 
 ####OpenAL Soft, slightly patched
 
-Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **\\Program Files (x86)\\Microsoft Visual Studio 14.0\\Common7\\Tools\\Shortcuts\\** folder), go to **D:\\TBuild\\Libraries** and run
+Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **Start Menu > Programs > Visual Studio 2015** menu folder), go to **D:\\TBuild\\Libraries** and run
 
     git clone git://repo.or.cz/openal-soft.git
     git checkout 90349b38
@@ -98,7 +98,7 @@ Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **\\Program Fi
 #####Building library
 
 * Install [CMake](http://www.cmake.org/)
-* Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **\\Program Files (x86)\\Microsoft Visual Studio 14.0\\Common7\\Tools\\Shortcuts\\** folder), go to **D:\TBuild\Libraries\openal-soft\build\** and run
+* Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **Start Menu > Programs > Visual Studio 2015** menu folder), go to **D:\TBuild\Libraries\openal-soft\build\** and run
 
     cmake -G "Visual Studio 14 2015" -D LIBTYPE:STRING=STATIC -D FORCE_STATIC_VCRT:STRING=ON ..
 
@@ -120,7 +120,7 @@ to have **D:\TBuild\Libraries\opus\win32**
 
 ####FFmpeg
 
-Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **\\Program Files (x86)\\Microsoft Visual Studio 14.0\\Common7\\Tools\\Shortcuts\\** folder) and run
+Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **Start Menu > Programs > Visual Studio 2015** menu folder) and run
 
     git clone https://github.com/FFmpeg/FFmpeg.git ffmpeg
     cd ffmpeg
@@ -132,7 +132,7 @@ http://msys2.github.io/ > Download [msys2-x86_64-20150512.exe](http://sourceforg
 
 Download [yasm for Win64](http://www.tortall.net/projects/yasm/releases/yasm-1.3.0-win64.exe) from http://yasm.tortall.net/Download.html, rename **yasm-1.3.0-win64.exe** to **yasm.exe** and place it to your Visual C++ **bin** directory, like **\\Program Files (x86)\\Microsoft Visual Studio 14\\VC\\bin\\**
 
-Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **\\Program Files (x86)\\Microsoft Visual Studio 14.0\\Common7\\Tools\\Shortcuts\\** folder), go to **D:\\msys64\\** and launch **msys2_shell.bat**, there run
+Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **Start Menu > Programs > Visual Studio 2015** menu folder), go to **D:\\msys64\\** and launch **msys2_shell.bat**, there run
 
     PATH="/c/Program Files (x86)/Microsoft Visual Studio 14.0/VC/BIN:$PATH"
 
@@ -153,7 +153,7 @@ Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **\\Program Fi
 ####Qt 5.5.1, slightly patched
 
 * Install Python 3.3.2 from https://www.python.org/download/releases/3.3.2 > [**Windows x86 MSI Installer (3.3.2)**](https://www.python.org/ftp/python/3.3.2/python-3.3.2.msi)
-* Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **\\Program Files (x86)\\Microsoft Visual Studio 14.0\\Common7\\Tools\\Shortcuts\\** folder)
+* Open **VS2015 x86 Native Tools Command Prompt.bat** (should be in **Start Menu > Programs > Visual Studio 2015** menu folder)
 
 There go to Libraries directory
 

Telegram/SourceFiles/gui/flatinput.cpp

@@ -970,9 +970,17 @@ void InputArea::onDocumentContentsChange(int position, int charsRemoved, int cha
 	QString oldtext(_oldtext);
 	QTextCursor(_inner.document()->docHandle(), 0).joinPreviousEditBlock();
 
-	QTextCursor c(_inner.document()->docHandle(), 0);
-	c.movePosition(QTextCursor::End);
-	int pos = c.position();
+	if (!position) { // Qt bug workaround https://bugreports.qt.io/browse/QTBUG-49062
+		QTextCursor c(_inner.document()->docHandle(), 0);
+		c.movePosition(QTextCursor::End);
+		if (position + charsAdded > c.position()) {
+			int32 toSubstract = position + charsAdded - c.position();
+			if (charsRemoved >= toSubstract) {
+				charsAdded -= toSubstract;
+				charsRemoved -= toSubstract;
+			}
+		}
+	}
 
 	_correcting = true;
 	if (_maxLength >= 0) {
@@ -1645,9 +1653,17 @@ void InputField::onDocumentContentsChange(int position, int charsRemoved, int ch
 	QString oldtext(_oldtext);
 	QTextCursor(_inner.document()->docHandle(), 0).joinPreviousEditBlock();
 
-	QTextCursor c(_inner.document()->docHandle(), 0);
-	c.movePosition(QTextCursor::End);
-	int pos = c.position();
+	if (!position) { // Qt bug workaround https://bugreports.qt.io/browse/QTBUG-49062
+		QTextCursor c(_inner.document()->docHandle(), 0);
+		c.movePosition(QTextCursor::End);
+		if (position + charsAdded > c.position()) {
+			int32 toSubstract = position + charsAdded - c.position();
+			if (charsRemoved >= toSubstract) {
+				charsAdded -= toSubstract;
+				charsRemoved -= toSubstract;
+			}
+		}
+	}
 
 	_correcting = true;
 	if (_maxLength >= 0) {