9.6

49 files changed, 161 insertions, 113 deletions

diff --git a/zen/basic_math.h b/zen/basic_math.h
index 22f29ca7..1b6b7e97 100755
--- a/zen/basic_math.h
+++ b/zen/basic_math.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
@@ -288,9 +288,9 @@ double median(RandomAccessIterator first, RandomAccessIterator last) //note: inv
 {
     const size_t n = last - first;
     if (n == 0)
-	    return 0;
+        return 0;
 
-	std::nth_element(first, first + n / 2, last); //complexity: O(n)
+    std::nth_element(first, first + n / 2, last); //complexity: O(n)
     const double midVal = *(first + n / 2);
 
     if (n % 2 != 0)
@@ -306,7 +306,7 @@ double mad(RandomAccessIterator first, RandomAccessIterator last) //note: invali
     //http://en.wikipedia.org/wiki/Median_absolute_deviation
     const size_t n = last - first;
     if (n == 0)
-	    return 0;
+        return 0;
 
     const double m = median(first, last);
 
diff --git a/zen/build_info.h b/zen/build_info.h
index 8354f492..7b0aa9cf 100755
--- a/zen/build_info.h
+++ b/zen/build_info.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/crc.h b/zen/crc.h
index 67f0460e..6f6ca996 100755
--- a/zen/crc.h
+++ b/zen/crc.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/deprecate.h b/zen/deprecate.h
index c2a1ebfa..2a6bcb0d 100755
--- a/zen/deprecate.h
+++ b/zen/deprecate.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/dir_watcher.cpp b/zen/dir_watcher.cpp
index 4e759d55..17f2244d 100755
--- a/zen/dir_watcher.cpp
+++ b/zen/dir_watcher.cpp
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/dir_watcher.h b/zen/dir_watcher.h
index 5676555f..8045d184 100755
--- a/zen/dir_watcher.h
+++ b/zen/dir_watcher.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/error_log.h b/zen/error_log.h
index 0d62dd1f..1fcbdefb 100755
--- a/zen/error_log.h
+++ b/zen/error_log.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/file_access.cpp b/zen/file_access.cpp
index e7467325..1711e934 100755
--- a/zen/file_access.cpp
+++ b/zen/file_access.cpp
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
@@ -379,17 +379,17 @@ void setWriteTimeNative(const Zstring& itemPath, const struct ::timespec& modTim
         using open()/futimens() for regular files and utimensat(AT_SYMLINK_NOFOLLOW) for symlinks is consistent with "cp" and "touch"!
     */
     struct ::timespec newTimes[2] = {};
-    newTimes[0].tv_sec = ::time(nullptr); //access time; using UTIME_OMIT for tv_nsec would trigger even more bugs: http://www.freefilesync.org/forum/viewtopic.php?t=1701
+    newTimes[0].tv_sec = ::time(nullptr); //access time; using UTIME_OMIT for tv_nsec would trigger even more bugs: https://www.freefilesync.org/forum/viewtopic.php?t=1701
     newTimes[1] = modTime; //modification time
 
     if (procSl == ProcSymlink::FOLLOW)
     {
         //hell knows why files on gvfs-mounted Samba shares fail to open(O_WRONLY) returning EOPNOTSUPP:
-        //http://www.freefilesync.org/forum/viewtopic.php?t=2803 => utimensat() works (but not for gvfs SFTP)
+        //https://www.freefilesync.org/forum/viewtopic.php?t=2803 => utimensat() works (but not for gvfs SFTP)
         if (::utimensat(AT_FDCWD, itemPath.c_str(), newTimes, 0) == 0)
             return;
 
-        //in other cases utimensat() returns EINVAL for CIFS/NTFS drives, but open+futimens works: http://www.freefilesync.org/forum/viewtopic.php?t=387
+        //in other cases utimensat() returns EINVAL for CIFS/NTFS drives, but open+futimens works: https://www.freefilesync.org/forum/viewtopic.php?t=387
         const int fdFile = ::open(itemPath.c_str(), O_WRONLY | O_APPEND); //2017-07-04: O_WRONLY | O_APPEND seems to avoid EOPNOTSUPP on gvfs SFTP!
         if (fdFile == -1)
             THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot write modification time of %x."), L"%x", fmtPath(itemPath)), L"open");
@@ -649,7 +649,7 @@ FileCopyResult copyFileOsSpecific(const Zstring& sourceFile, //throw FileError,
         //this triggers bugs on samba shares where the modification time is set to current time instead.
         //Linux: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=340236
         //       http://comments.gmane.org/gmane.linux.file-systems.cifs/2854
-        //OS X:  http://www.freefilesync.org/forum/viewtopic.php?t=356
+        //OS X:  https://www.freefilesync.org/forum/viewtopic.php?t=356
         setWriteTimeNative(targetFile, sourceInfo.st_mtim, ProcSymlink::FOLLOW); //throw FileError
     }
     catch (const FileError& e)
diff --git a/zen/file_access.h b/zen/file_access.h
index 0a9b2d0c..743ad15d 100755
--- a/zen/file_access.h
+++ b/zen/file_access.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/file_error.h b/zen/file_error.h
index 18e790de..decc0f7e 100755
--- a/zen/file_error.h
+++ b/zen/file_error.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/file_id_def.h b/zen/file_id_def.h
index 8d429fbc..7772e3e3 100755
--- a/zen/file_id_def.h
+++ b/zen/file_id_def.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/file_io.cpp b/zen/file_io.cpp
index 68b41bcb..bb4848c6 100755
--- a/zen/file_io.cpp
+++ b/zen/file_io.cpp
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
@@ -115,6 +115,8 @@ size_t FileInput::tryRead(void* buffer, size_t bytesToRead) //throw FileError, E
         bytesRead = ::read(getHandle(), buffer, bytesToRead);
     }
     while (bytesRead < 0 && errno == EINTR); //Compare copy_reg() in copy.c: ftp://ftp.gnu.org/gnu/coreutils/coreutils-8.23.tar.xz
+    //EINTR is not checked on macOS' copyfile: https://opensource.apple.com/source/copyfile/copyfile-146/copyfile.c.auto.html
+    //read() on macOS: https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man2/read.2.html
 
     if (bytesRead < 0)
         THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot read file %x."), L"%x", fmtPath(getFilePath())), L"read");
@@ -129,23 +131,41 @@ size_t FileInput::tryRead(void* buffer, size_t bytesToRead) //throw FileError, E
 
 size_t FileInput::read(void* buffer, size_t bytesToRead) //throw FileError, ErrorFileLocked, X; return "bytesToRead" bytes unless end of stream!
 {
+    warn_static("implement PERF_AWESOME_BUFFER program wide for all buffers!?")
+
+    /*
+        FFS 8.9-9.5 perf issues on macOS: https://www.freefilesync.org/forum/viewtopic.php?t=4808
+            app-level buffering is essential to optimize random data sizes; e.g. "export file list":
+                => big perf improvement on Windows, Linux. No significant improvement on macOS in tests
+            impact on stream-based file copy:
+                => no drawback vs block-wise copy loop on Linux, HOWEVER: big perf issue on macOS!
+
+        Possible cause of macOS perf issue unclear:
+            - getting rid of std::vector::resize() and std::vector::erase() "fixed" the problem
+                => costly zero-initializing memory? problem with inlining? QOI issue of std:vector on clang/macOS?
+            - replacing std::copy() with memcpy() also *seems* to have improved speed "somewhat"
+    */
+
     const size_t blockSize = getBlockSize();
-    assert(memBuf_.size() <= blockSize);
+    assert(memBuf_.size() >= blockSize);
+    assert(bufPos_ <= bufPosEnd_ && bufPosEnd_ <= memBuf_.size());
+
     char*       it    = static_cast<char*>(buffer);
     char* const itEnd = it + bytesToRead;
     for (;;)
     {
-        const size_t junkSize = std::min(static_cast<size_t>(itEnd - it), memBuf_.size());
-        std::copy    (memBuf_.begin(), memBuf_.begin() + junkSize, it);
-        memBuf_.erase(memBuf_.begin(), memBuf_.begin() + junkSize);
-        it += junkSize;
+        const size_t junkSize = std::min(static_cast<size_t>(itEnd - it), bufPosEnd_ - bufPos_);
+        std::memcpy(it, &memBuf_[bufPos_], junkSize);
+        bufPos_ += junkSize;
+        it      += junkSize;
 
         if (it == itEnd)
             break;
+
         //--------------------------------------------------------------------
-        memBuf_.resize(blockSize);
         const size_t bytesRead = tryRead(&memBuf_[0], blockSize); //throw FileError, ErrorFileLocked; may return short, only 0 means EOF! => CONTRACT: bytesToRead > 0
-        memBuf_.resize(bytesRead);
+        bufPos_ = 0;
+        bufPosEnd_ = bytesRead;
 
         if (notifyUnbufferedIO_) notifyUnbufferedIO_(bytesRead); //throw X
 
@@ -213,6 +233,7 @@ size_t FileOutput::tryWrite(const void* buffer, size_t bytesToWrite) //throw Fil
         bytesWritten = ::write(getHandle(), buffer, bytesToWrite);
     }
     while (bytesWritten < 0 && errno == EINTR);
+    //write() on macOS: https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man2/write.2.html
 
     if (bytesWritten <= 0)
     {
@@ -232,20 +253,32 @@ size_t FileOutput::tryWrite(const void* buffer, size_t bytesToWrite) //throw Fil
 void FileOutput::write(const void* buffer, size_t bytesToWrite) //throw FileError, X
 {
     const size_t blockSize = getBlockSize();
-    assert(memBuf_.size() <= blockSize);
-    const char*       it   = static_cast<const char*>(buffer);
+    assert(memBuf_.size() >= blockSize);
+    assert(bufPos_ <= bufPosEnd_ && bufPosEnd_ <= memBuf_.size());
+
+    const char*       it    = static_cast<const char*>(buffer);
     const char* const itEnd = it + bytesToWrite;
     for (;;)
     {
-        const size_t junkSize = std::min(static_cast<size_t>(itEnd - it), blockSize - memBuf_.size());
-        memBuf_.insert(memBuf_.end(), it, it + junkSize);
-        it += junkSize;
+        if (memBuf_.size() - bufPos_ < blockSize) //support memBuf_.size() > blockSize to reduce memmove()s, but perf test shows: not really needed!
+            // || bufPos_ == bufPosEnd_) -> not needed while memBuf_.size() == blockSize
+        {
+            std::memmove(&memBuf_[0], &memBuf_[bufPos_], bufPosEnd_ - bufPos_);
+            bufPosEnd_ -= bufPos_;
+            bufPos_ = 0;
+        }
+
+        const size_t junkSize = std::min(static_cast<size_t>(itEnd - it), blockSize - (bufPosEnd_ - bufPos_));
+        std::memcpy(&memBuf_[bufPosEnd_], it, junkSize);
+        bufPosEnd_ += junkSize;
+        it         += junkSize;
 
         if (it == itEnd)
             return;
+
         //--------------------------------------------------------------------
-        const size_t bytesWritten = tryWrite(&memBuf_[0], blockSize); //throw FileError; may return short! CONTRACT: bytesToWrite > 0
-        memBuf_.erase(memBuf_.begin(), memBuf_.begin() + bytesWritten);
+        const size_t bytesWritten = tryWrite(&memBuf_[bufPos_], blockSize); //throw FileError; may return short! CONTRACT: bytesToWrite > 0
+        bufPos_ += bytesWritten;
         if (notifyUnbufferedIO_) notifyUnbufferedIO_(bytesWritten); //throw X!
     }
 }
@@ -253,11 +286,12 @@ void FileOutput::write(const void* buffer, size_t bytesToWrite) //throw FileErro
 
 void FileOutput::flushBuffers() //throw FileError, X
 {
-    assert(memBuf_.size() <= getBlockSize());
-    while (!memBuf_.empty())
+    assert(bufPosEnd_ - bufPos_ <= getBlockSize());
+    assert(bufPos_ <= bufPosEnd_ && bufPosEnd_ <= memBuf_.size());
+    while (bufPos_ != bufPosEnd_)
     {
-        const size_t bytesWritten = tryWrite(&memBuf_[0], memBuf_.size()); //throw FileError; may return short! CONTRACT: bytesToWrite > 0
-        memBuf_.erase(memBuf_.begin(), memBuf_.begin() + bytesWritten);
+        const size_t bytesWritten = tryWrite(&memBuf_[bufPos_], bufPosEnd_ - bufPos_); //throw FileError; may return short! CONTRACT: bytesToWrite > 0
+        bufPos_ += bytesWritten;
         if (notifyUnbufferedIO_) notifyUnbufferedIO_(bytesWritten); //throw X!
     }
 }
diff --git a/zen/file_io.h b/zen/file_io.h
index c2071500..369cdc01 100755
--- a/zen/file_io.h
+++ b/zen/file_io.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
@@ -64,8 +64,11 @@ public:
 private:
     size_t tryRead(void* buffer, size_t bytesToRead); //throw FileError, ErrorFileLocked; may return short, only 0 means EOF! =>  CONTRACT: bytesToRead > 0!
 
-    std::vector<char> memBuf_;
     const IOCallback notifyUnbufferedIO_; //throw X
+
+    std::vector<char> memBuf_ = std::vector<char>(getBlockSize());
+    size_t bufPos_   = 0;
+    size_t bufPosEnd_= 0;
 };
 
 
@@ -90,8 +93,11 @@ public:
 private:
     size_t tryWrite(const void* buffer, size_t bytesToWrite); //throw FileError; may return short! CONTRACT: bytesToWrite > 0
 
-    std::vector<char> memBuf_;
     IOCallback notifyUnbufferedIO_; //throw X
+
+    std::vector<char> memBuf_ = std::vector<char>(getBlockSize());
+    size_t bufPos_    = 0;
+    size_t bufPosEnd_ = 0;
 };
 
 //-----------------------------------------------------------------------------------------------
diff --git a/zen/file_traverser.cpp b/zen/file_traverser.cpp
index 916b6e8d..aa4c439e 100755
--- a/zen/file_traverser.cpp
+++ b/zen/file_traverser.cpp
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/file_traverser.h b/zen/file_traverser.h
index 1f7142de..19359148 100755
--- a/zen/file_traverser.h
+++ b/zen/file_traverser.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/fixed_list.h b/zen/fixed_list.h
index 27eb488c..535ffa31 100755
--- a/zen/fixed_list.h
+++ b/zen/fixed_list.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/format_unit.cpp b/zen/format_unit.cpp
index e62c9286..0f54a34b 100755
--- a/zen/format_unit.cpp
+++ b/zen/format_unit.cpp
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/format_unit.h b/zen/format_unit.h
index 3dcc6858..154ec542 100755
--- a/zen/format_unit.h
+++ b/zen/format_unit.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/globals.h b/zen/globals.h
index b85d5f77..32781f2a 100755
--- a/zen/globals.h
+++ b/zen/globals.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/guid.h b/zen/guid.h
index f47a141c..633547ad 100755
--- a/zen/guid.h
+++ b/zen/guid.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/i18n.h b/zen/i18n.h
index e6d97b7b..bb6dbac5 100755
--- a/zen/i18n.h
+++ b/zen/i18n.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/optional.h b/zen/optional.h
index 0efc34fe..a2a1a169 100755
--- a/zen/optional.h
+++ b/zen/optional.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/perf.h b/zen/perf.h
index bd21159c..72b57f52 100755
--- a/zen/perf.h
+++ b/zen/perf.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/process_priority.cpp b/zen/process_priority.cpp
index 5767e60c..e925f142 100755
--- a/zen/process_priority.cpp
+++ b/zen/process_priority.cpp
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/process_priority.h b/zen/process_priority.h
index ac96a8ae..bec8f9b5 100755
--- a/zen/process_priority.h
+++ b/zen/process_priority.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/recycler.cpp b/zen/recycler.cpp
index c84ef8f3..30b37cb2 100755
--- a/zen/recycler.cpp
+++ b/zen/recycler.cpp
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/recycler.h b/zen/recycler.h
index 54dd75ca..0e5ebbb1 100755
--- a/zen/recycler.h
+++ b/zen/recycler.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/scope_guard.h b/zen/scope_guard.h
index ccc6db0c..2048af9b 100755
--- a/zen/scope_guard.h
+++ b/zen/scope_guard.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/serialize.h b/zen/serialize.h
index 8f7e813c..381d102a 100755
--- a/zen/serialize.h
+++ b/zen/serialize.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/shell_execute.h b/zen/shell_execute.h
index 077f18e7..18e4854b 100755
--- a/zen/shell_execute.h
+++ b/zen/shell_execute.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
@@ -9,14 +9,14 @@
 
 #include "file_error.h"
 
-    #include "thread.h"
+    #include <unistd.h> //fork()
     #include <stdlib.h> //::system()
 
 
 namespace zen
 {
 //launch commandline and report errors via popup dialog
-//windows: COM needs to be initialized before calling this function!
+//Windows: COM needs to be initialized before calling this function!
 enum ExecutionType
 {
     EXEC_TYPE_SYNC,
@@ -38,24 +38,34 @@ void shellExecute(const Zstring& command, ExecutionType type) //throw FileError
 
     if (type == EXEC_TYPE_SYNC)
     {
-        //Posix::system - execute a shell command
+        //Posix ::system() - execute a shell command
         const int rv = ::system(command.c_str()); //do NOT use std::system as its documentation says nothing about "WEXITSTATUS(rv)", ect...
-        if (rv == -1 || WEXITSTATUS(rv) == 127) //http://linux.die.net/man/3/system    "In case /bin/sh could not be executed, the exit status will be that of a command that does exit(127)"
+        if (rv == -1 || WEXITSTATUS(rv) == 127)
             throw FileError(_("Incorrect command line:") + L"\n" + utfTo<std::wstring>(command));
+        //http://linux.die.net/man/3/system    "In case /bin/sh could not be executed, the exit status will be that of a command that does exit(127)"
+        //Bonus: For an incorrect command line /bin/sh also returns with 127!
     }
     else
-	{
-		runAsync([=] { int rv = ::system(command.c_str()); (void)rv; });
-
-		warn_static("finish:")
-
-
-
-
-
-
-
-	}
+    {
+        //follow implemenation of ::system() except for waitpid():
+        const pid_t pid = ::fork();
+        if (pid < 0) //pids are never negative, empiric proof: https://linux.die.net/man/2/wait
+            THROW_LAST_FILE_ERROR(_("Incorrect command line:") + L"\n" + utfTo<std::wstring>(command), L"fork");
+
+        if (pid == 0) //child process
+        {
+            const char* argv[] = { "sh", "-c", command.c_str(), nullptr };
+            /*int rv =*/::execv("/bin/sh", const_cast<char**>(argv));
+            //safe to cast away const: http://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html
+            //  "The statement about argv[] and envp[] being constants is included to make explicit to future
+            //   writers of language bindings that these objects are completely constant. Due to a limitation of
+            //   the ISO C standard, it is not possible to state that idea in standard C."
+
+            //"execv() only returns if an error has occurred. The return value is -1, and errno is set to indicate the error."
+            ::_exit(127); //[!] avoid flushing I/O buffers or doing other clean up from child process like with "exit(127)"!
+        }
+        //else //parent process
+    }
 }
 }
 }
diff --git a/zen/shutdown.cpp b/zen/shutdown.cpp
index b21ab8db..dd02814f 100755
--- a/zen/shutdown.cpp
+++ b/zen/shutdown.cpp
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
@@ -17,18 +17,16 @@ void zen::shutdownSystem() //throw FileError
 {
     //https://linux.die.net/man/2/reboot => needs admin rights!
 
-    //should work without admin rights:
+    //"systemctl" should work without admin rights:
     shellExecute("sleep 1; systemctl poweroff", EXEC_TYPE_ASYNC); //throw FileError
     //sleep 1: give FFS some time to properly shut down!
-    //Linux: main thread will wait on detached threads!
-    warn_static("get rid of shellExecute's thread implementation!")
 
 }
 
 
 void zen::suspendSystem() //throw FileError
 {
-    //should work without admin rights:
+    //"systemctl" should work without admin rights:
     shellExecute("systemctl suspend", EXEC_TYPE_ASYNC); //throw FileError
 
 }
@@ -38,25 +36,25 @@ Command line alternatives:
 
 #ifdef ZEN_WIN
 #ifdef ZEN_WIN_VISTA_AND_LATER
-	Shut down:	shutdown /s /t 60
-	Sleep:		rundll32.exe powrprof.dll,SetSuspendState Sleep
-	Log off:	shutdown /l
+    Shut down:  shutdown /s /t 60
+    Sleep:      rundll32.exe powrprof.dll,SetSuspendState Sleep
+    Log off:    shutdown /l
 #else //XP
-    Shut down:	shutdown -s -t 60
-    Standby:	rundll32.exe powrprof.dll,SetSuspendState	//this triggers standby OR hibernate, depending on whether hibernate setting is active! no suspend on XP?
-    Log off:	shutdown -l
+    Shut down:  shutdown -s -t 60
+    Standby:    rundll32.exe powrprof.dll,SetSuspendState   //this triggers standby OR hibernate, depending on whether hibernate setting is active! no suspend on XP?
+    Log off:    shutdown -l
 #endif
 
 #elif defined ZEN_LINUX
-    Shut down:	systemctl poweroff		//alternative requiring admin: sudo shutdown -h 1
-    Sleep:		systemctl suspend  		//alternative requiring admin: sudo pm-suspend
-    Log off:	gnome-session-quit --no-prompt
-		//alternative requiring admin: sudo killall Xorg
-		//alternative without admin: dbus-send --session --print-reply --dest=org.gnome.SessionManager /org/gnome/SessionManager org.gnome.SessionManager.Logout uint32:1
+    Shut down:  systemctl poweroff      //alternative requiring admin: sudo shutdown -h 1
+    Sleep:      systemctl suspend       //alternative requiring admin: sudo pm-suspend
+    Log off:    gnome-session-quit --no-prompt
+        //alternative requiring admin: sudo killall Xorg
+        //alternative without admin: dbus-send --session --print-reply --dest=org.gnome.SessionManager /org/gnome/SessionManager org.gnome.SessionManager.Logout uint32:1
 
 #elif defined ZEN_MAC
-    Shut down:	osascript -e 'tell application "System Events" to shut down'
-    Sleep:		osascript -e 'tell application "System Events" to sleep'
-    Log off:	osascript -e 'tell application "System Events" to log out'
+    Shut down:  osascript -e 'tell application "System Events" to shut down'
+    Sleep:      osascript -e 'tell application "System Events" to sleep'
+    Log off:    osascript -e 'tell application "System Events" to log out'
 #endif
 */
diff --git a/zen/shutdown.h b/zen/shutdown.h
index e64dee41..b9d47df6 100755
--- a/zen/shutdown.h
+++ b/zen/shutdown.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/stl_tools.h b/zen/stl_tools.h
index 2fcecd11..ba4a6c89 100755
--- a/zen/stl_tools.h
+++ b/zen/stl_tools.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/string_base.h b/zen/string_base.h
index cb7ced20..30699c38 100755
--- a/zen/string_base.h
+++ b/zen/string_base.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/string_tools.h b/zen/string_tools.h
index 0a24ab2a..5058f78d 100755
--- a/zen/string_tools.h
+++ b/zen/string_tools.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/string_traits.h b/zen/string_traits.h
index f17e5e0d..502250c2 100755
--- a/zen/string_traits.h
+++ b/zen/string_traits.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/symlink_target.h b/zen/symlink_target.h
index 6ff7f327..2393013e 100755
--- a/zen/symlink_target.h
+++ b/zen/symlink_target.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/sys_error.cpp b/zen/sys_error.cpp
index fd4c8f1e..2acaca1d 100755
--- a/zen/sys_error.cpp
+++ b/zen/sys_error.cpp
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/sys_error.h b/zen/sys_error.h
index f4361e69..31eb8209 100755
--- a/zen/sys_error.h
+++ b/zen/sys_error.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/thread.h b/zen/thread.h
index 85e64493..0bff5adc 100755
--- a/zen/thread.h
+++ b/zen/thread.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/time.h b/zen/time.h
index 2ac67399..67156b9a 100755
--- a/zen/time.h
+++ b/zen/time.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/type_tools.h b/zen/type_tools.h
index d0a62ea2..a705d9bd 100755
--- a/zen/type_tools.h
+++ b/zen/type_tools.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/type_traits.h b/zen/type_traits.h
index 917b3258..f0f96b43 100755
--- a/zen/type_traits.h
+++ b/zen/type_traits.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/utf.h b/zen/utf.h
index bc1e3270..820148c6 100755
--- a/zen/utf.h
+++ b/zen/utf.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/warn_static.h b/zen/warn_static.h
index c2232f74..5b9a4fee 100755
--- a/zen/warn_static.h
+++ b/zen/warn_static.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/xml_io.cpp b/zen/xml_io.cpp
index 8192d6e6..a618f27c 100755
--- a/zen/xml_io.cpp
+++ b/zen/xml_io.cpp
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/xml_io.h b/zen/xml_io.h
index 6c2fc720..8d3346c6 100755
--- a/zen/xml_io.h
+++ b/zen/xml_io.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
diff --git a/zen/zstring.cpp b/zen/zstring.cpp
index fb62424a..2aa3b3f2 100755
--- a/zen/zstring.cpp
+++ b/zen/zstring.cpp
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************
 
@@ -75,11 +75,11 @@ int cmpStringNaturalLinux(const char* lhs, size_t lhsLen, const char* rhs, size_
         - implement strict weak ordering!
         - don't follow broken "strnatcasecmp": https://github.com/php/php-src/blob/master/ext/standard/strnatcmp.c
                 1. incorrect non-ASCII CI-comparison
-				2. incorrect bounds checks
+                2. incorrect bounds checks
                 3. incorrect trimming of *all* whitespace
-				4. arbitrary handling of leading 0 only at string begin
+                4. arbitrary handling of leading 0 only at string begin
                 5. incorrect handling of whitespace following a number
-				6. code is a mess
+                6. code is a mess
     */
     for (;;)
     {
diff --git a/zen/zstring.h b/zen/zstring.h
index 33f48990..2a4a549e 100755
--- a/zen/zstring.h
+++ b/zen/zstring.h
@@ -1,6 +1,6 @@
 // *****************************************************************************
 // * This file is part of the FreeFileSync project. It is distributed under    *
-// * GNU General Public License: http://www.gnu.org/licenses/gpl-3.0           *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
 // * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
 // *****************************************************************************