Merge branch '11.0' into 'master'11.0

add upstream 11.0

See merge request opensource-tracking/FreeFileSync!24

21 files changed, 126 insertions, 147 deletions

diff --git a/zen/base64.h b/zen/base64.h
index 623f8f7f..b39a6a52 100644
--- a/zen/base64.h
+++ b/zen/base64.h
@@ -114,7 +114,7 @@ OutputIterator decodeBase64(InputIterator first, InputIterator last, OutputItera
                 return INDEX_END;
 
             const unsigned char ch = static_cast<unsigned char>(*first++);
-            if (ch < 128) //we're in lower ASCII table half
+            if (ch < arraySize(DECODING_MIME)) //we're in lower ASCII table half
             {
                 const int index = DECODING_MIME[ch];
                 if (0 <= index && index <= static_cast<int>(INDEX_PAD)) //skip all unknown characters (including carriage return, line-break, tab)
diff --git a/zen/error_log.h b/zen/error_log.h
index ab23e33a..8604f127 100644
--- a/zen/error_log.h
+++ b/zen/error_log.h
@@ -19,16 +19,15 @@ namespace zen
 {
 enum MessageType
 {
-    MSG_TYPE_INFO        = 0x1,
-    MSG_TYPE_WARNING     = 0x2,
-    MSG_TYPE_ERROR       = 0x4,
-    MSG_TYPE_FATAL_ERROR = 0x8,
+    MSG_TYPE_INFO    = 0x1,
+    MSG_TYPE_WARNING = 0x2,
+    MSG_TYPE_ERROR   = 0x4,
 };
 
 struct LogEntry
 {
     time_t      time = 0;
-    MessageType type = MSG_TYPE_FATAL_ERROR;
+    MessageType type = MSG_TYPE_ERROR;
     Zstringc message; //conserve memory (=> avoid std::string SSO overhead!)
 };
 
@@ -45,7 +44,6 @@ public:
         int info    = 0;
         int warning = 0;
         int error   = 0;
-        int fatal   = 0;
     };
     Stats getStats() const;
 
@@ -91,11 +89,8 @@ ErrorLog::Stats ErrorLog::getStats() const
             case MSG_TYPE_ERROR:
                 ++count.error;
                 break;
-            case MSG_TYPE_FATAL_ERROR:
-                ++count.fatal;
-                break;
         }
-    assert(static_cast<int>(entries_.size()) == count.info + count.warning + count.error + count.fatal);
+    assert(static_cast<int>(entries_.size()) == count.info + count.warning + count.error);
     return count;
 }
 
@@ -111,8 +106,6 @@ std::wstring getMessageTypeLabel(MessageType type)
             return _("Warning");
         case MSG_TYPE_ERROR:
             return _("Error");
-        case MSG_TYPE_FATAL_ERROR:
-            return _("Serious Error");
     }
     assert(false);
     return std::wstring();
diff --git a/zen/file_access.cpp b/zen/file_access.cpp
index 8f021843..10713ce5 100644
--- a/zen/file_access.cpp
+++ b/zen/file_access.cpp
@@ -176,7 +176,7 @@ int64_t zen::getFreeDiskSpace(const Zstring& path) //throw FileError, returns <
     struct ::statfs info = {};
     if (::statfs(path.c_str(), &info) != 0)
         THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot determine free disk space for %x."), L"%x", fmtPath(path)), "statfs");
-        
+
     return static_cast<int64_t>(info.f_bsize) * info.f_bavail;
 }
 
@@ -205,11 +205,12 @@ Zstring zen::getTempFolderPath() //throw FileError
 {
     if (const char* buf = ::getenv("TMPDIR")) //no extended error reporting
         return buf;
-
+    //TMPDIR not set on CentOS 7, WTF!
     return P_tmpdir; //usually resolves to "/tmp"
 }
 
 
+
 void zen::removeFilePlain(const Zstring& filePath) //throw FileError
 {
     const char* functionName = "unlink";
@@ -300,11 +301,11 @@ namespace
 
 /* Usage overview: (avoid circular pattern!)
 
-  moveAndRenameItem()  -->  moveAndRenameFileSub()
-      |                              /|\
-     \|/                              |
-             Fix8Dot3NameClash()
-*/
+  moveAndRenameItem() --> moveAndRenameFileSub()
+      |                            /|\
+     \|/                            |
+             Fix8Dot3NameClash()                */
+
 //wrapper for file system rename function:
 void moveAndRenameFileSub(const Zstring& pathFrom, const Zstring& pathTo, bool replaceExisting) //throw FileError, ErrorMoveUnsupported, ErrorTargetExisting
 {
@@ -521,10 +522,12 @@ void zen::createDirectory(const Zstring& dirPath) //throw FileError, ErrorTarget
     if (std::all_of(dirName.begin(), dirName.end(), [](Zchar c) { return c == Zstr('.'); }))
     /**/throw FileError(getErrorMsg(), replaceCpy<std::wstring>(L"Invalid folder name %x.", L"%x", fmtPath(dirName)));
 
+    #if 0 //not appreciated: https://freefilesync.org/forum/viewtopic.php?t=7509
     //not critical, but will visually confuse user sooner or later:
     if (startsWith(dirName, Zstr(' ')) ||
         endsWith  (dirName, Zstr(' ')))
         throw FileError(getErrorMsg(), replaceCpy<std::wstring>(L"Folder name %x starts/ends with space character.", L"%x", fmtPath(dirName)));
+    #endif
 
     const mode_t mode = S_IRWXU | S_IRWXG | S_IRWXO; //0777, default for newly created directories
 
@@ -542,16 +545,16 @@ void zen::createDirectory(const Zstring& dirPath) //throw FileError, ErrorTarget
 }
 
 
-void zen::createDirectoryIfMissingRecursion(const Zstring& dirPath) //throw FileError
+bool zen::createDirectoryIfMissingRecursion(const Zstring& dirPath) //throw FileError
 {
     const std::optional<Zstring> parentPath = getParentFolderPath(dirPath);
     if (!parentPath) //device root
-        return;
+        return false;
 
     try //generally we expect that path already exists (see: ffs_paths.cpp) => check first
     {
         if (getItemType(dirPath) != ItemType::file) //throw FileError
-            return;
+            return false;
     }
     catch (FileError&) {} //not yet existing or access error? let's find out...
 
@@ -560,13 +563,14 @@ void zen::createDirectoryIfMissingRecursion(const Zstring& dirPath) //throw File
     try
     {
         createDirectory(dirPath); //throw FileError, ErrorTargetExisting
+        return true;
     }
     catch (FileError&)
     {
         try
         {
             if (getItemType(dirPath) != ItemType::file) //throw FileError
-                return; //already existing => possible, if createDirectoryIfMissingRecursion() is run in parallel
+                return true; //already existing => possible, if createDirectoryIfMissingRecursion() is run in parallel
         }
         catch (FileError&) {} //not yet existing or access error
 
@@ -580,12 +584,19 @@ void zen::tryCopyDirectoryAttributes(const Zstring& sourcePath, const Zstring& t
 }
 
 
-void zen::copySymlink(const Zstring& sourcePath, const Zstring& targetPath, bool copyFilePermissions) //throw FileError
+void zen::copySymlink(const Zstring& sourcePath, const Zstring& targetPath) //throw FileError
 {
-    const Zstring linkPath = getSymlinkTargetRaw(sourcePath); //throw FileError; accept broken symlinks
+    const SymlinkRawContent linkContent = getSymlinkRawContent(sourcePath); //throw FileError; accept broken symlinks
 
-    if (::symlink(linkPath.c_str(), targetPath.c_str()) != 0)
-        THROW_LAST_FILE_ERROR(replaceCpy(replaceCpy(_("Cannot copy symbolic link %x to %y."), L"%x", L'\n' + fmtPath(sourcePath)), L"%y", L'\n' + fmtPath(targetPath)), "symlink");
+    try //harmonize with NativeFileSystem::equalSymlinkContentForSameAfsType()
+    {
+        if (::symlink(linkContent.targetPath.c_str(), targetPath.c_str()) != 0)
+            THROW_LAST_SYS_ERROR("symlink");
+    }
+    catch (const SysError& e)
+    {
+        throw FileError(replaceCpy(replaceCpy(_("Cannot copy symbolic link %x to %y."), L"%x", L'\n' + fmtPath(sourcePath)), L"%y", L'\n' + fmtPath(targetPath)), e.toString());
+    }
 
     //allow only consistent objects to be created -> don't place before ::symlink(); targetPath may already exist!
     ZEN_ON_SCOPE_FAIL(try { removeSymlinkPlain(targetPath); /*throw FileError*/ }
@@ -597,17 +608,11 @@ void zen::copySymlink(const Zstring& sourcePath, const Zstring& targetPath, bool
         THROW_LAST_FILE_ERROR(replaceCpy(_("Cannot read file attributes of %x."), L"%x", fmtPath(sourcePath)), "lstat");
 
     setWriteTimeNative(targetPath, sourceInfo.st_mtim, ProcSymlink::DIRECT); //throw FileError
-
-    if (copyFilePermissions)
-        copyItemPermissions(sourcePath, targetPath, ProcSymlink::DIRECT); //throw FileError
 }
 
 
-namespace
-{
-FileCopyResult copyFileOsSpecific(const Zstring& sourceFile, //throw FileError, ErrorTargetExisting
-                                  const Zstring& targetFile,
-                                  const IOCallback& notifyUnbufferedIO)
+FileCopyResult zen::copyNewFile(const Zstring& sourceFile, const Zstring& targetFile, //throw FileError, ErrorTargetExisting, (ErrorFileLocked), X
+                                const IOCallback& notifyUnbufferedIO /*throw X*/)
 {
     int64_t totalUnbufferedIO = 0;
 
@@ -678,33 +683,4 @@ FileCopyResult copyFileOsSpecific(const Zstring& sourceFile, //throw FileError,
     return result;
 }
 
-/*                  ------------------
-                    |File Copy Layers|
-                    ------------------
-                       copyNewFile
-                            |
-                   copyFileOsSpecific (solve 8.3 issue on Windows)
-                            |
-                  copyFileWindowsSelectRoutine
-                  /                           \
-copyFileWindowsDefault(::CopyFileEx)  copyFileWindowsStream(::BackupRead/::BackupWrite)
-*/
-}
-
-
-FileCopyResult zen::copyNewFile(const Zstring& sourceFile, const Zstring& targetFile, bool copyFilePermissions, //throw FileError, ErrorTargetExisting, ErrorFileLocked, X
-                                const IOCallback& notifyUnbufferedIO /*throw X*/)
-{
-    const FileCopyResult result = copyFileOsSpecific(sourceFile, targetFile, notifyUnbufferedIO); //throw FileError, ErrorTargetExisting, ErrorFileLocked, X
-
-    //at this point we know we created a new file, so it's fine to delete it for cleanup!
-    ZEN_ON_SCOPE_FAIL(try { removeFilePlain(targetFile); }
-    catch (FileError&) {});
-
-    if (copyFilePermissions)
-        copyItemPermissions(sourceFile, targetFile, ProcSymlink::FOLLOW); //throw FileError
-
-    return result;
-}
-
 
diff --git a/zen/file_access.h b/zen/file_access.h
index 66c41fbd..a3fa56d7 100644
--- a/zen/file_access.h
+++ b/zen/file_access.h
@@ -52,7 +52,7 @@ enum class ProcSymlink
 };
 void setFileTime(const Zstring& filePath, time_t modTime, ProcSymlink procSl); //throw FileError
 
-//symlink handling: always follow:
+//symlink handling: follow
 int64_t getFreeDiskSpace(const Zstring& path); //throw FileError, returns < 0 if not available
 VolumeId getVolumeId(const Zstring& itemPath); //throw FileError
 uint64_t getFileSize(const Zstring& filePath); //throw FileError
@@ -73,16 +73,16 @@ void copyItemPermissions(const Zstring& sourcePath, const Zstring& targetPath, P
 
 void createDirectory(const Zstring& dirPath); //throw FileError, ErrorTargetExisting
 
-//- no error if already existing
-//- create recursively if parent directory is not existing
-void createDirectoryIfMissingRecursion(const Zstring& dirPath); //throw FileError
+//creates directories recursively if not existing
+//returns false if folder already exists
+bool createDirectoryIfMissingRecursion(const Zstring& dirPath); //throw FileError
 
-//symlink handling: follow link!
+//symlink handling: follow
 //expects existing source/target directories
-//reports note-worthy errors only
+//reports "note-worthy" errors only
 void tryCopyDirectoryAttributes(const Zstring& sourcePath, const Zstring& targetPath); //throw FileError
 
-void copySymlink(const Zstring& sourcePath, const Zstring& targetPath, bool copyFilePermissions); //throw FileError
+void copySymlink(const Zstring& sourcePath, const Zstring& targetPath); //throw FileError
 
 struct FileCopyResult
 {
@@ -93,7 +93,7 @@ struct FileCopyResult
     std::optional<FileError> errorModTime; //failure to set modification time
 };
 
-FileCopyResult copyNewFile(const Zstring& sourceFile, const Zstring& targetFile, bool copyFilePermissions, //throw FileError, ErrorTargetExisting, ErrorFileLocked, X
+FileCopyResult copyNewFile(const Zstring& sourceFile, const Zstring& targetFile, //throw FileError, ErrorTargetExisting, ErrorFileLocked, X
                            //accummulated delta != file size! consider ADS, sparse, compressed files
                            const IOCallback& notifyUnbufferedIO /*throw X*/);
 
diff --git a/zen/file_io.cpp b/zen/file_io.cpp
index 942f367f..80a83724 100644
--- a/zen/file_io.cpp
+++ b/zen/file_io.cpp
@@ -46,23 +46,21 @@ namespace
 {
 FileBase::FileHandle openHandleForRead(const Zstring& filePath) //throw FileError, ErrorFileLocked
 {
-    //- "filePath" could be a named pipe which *blocks* forever for open()!
-    //- open() with O_NONBLOCK avoids the block, but opens successfully
-    //- create sample pipe: "sudo mkfifo named_pipe"
+    //caveat: check for file types that block during open(): character device, block device, named pipe
     struct ::stat fileInfo = {};
     if (::stat(filePath.c_str(), &fileInfo) == 0) //follows symlinks
     {
         if (!S_ISREG(fileInfo.st_mode) &&
-            !S_ISLNK(fileInfo.st_mode) &&
-            !S_ISDIR(fileInfo.st_mode))
+            !S_ISDIR(fileInfo.st_mode) && //open() will fail with "EISDIR: Is a directory" => nice
+            !S_ISLNK(fileInfo.st_mode)) //?? shouldn't be possible after successful stat()
         {
             const std::wstring typeName = [m = fileInfo.st_mode]
             {
                 std::wstring name =
-                S_ISCHR (m) ? L"character device" :
-                S_ISBLK (m) ? L"block device" :
+                S_ISCHR (m) ? L"character device" : //e.g. /dev/null
+                S_ISBLK (m) ? L"block device" :     //e.g. /dev/sda1
                 S_ISFIFO(m) ? L"FIFO, named pipe" :
-                S_ISSOCK(m) ? L"socket" : L"";
+                S_ISSOCK(m) ? L"socket" : L""; //doesn't block but open() error is unclear: "ENXIO: No such device or address"
                 if (!name.empty())
                     name += L", ";
                 return name + printNumber<std::wstring>(L"0%06o", m & S_IFMT);
diff --git a/zen/http.cpp b/zen/http.cpp
index 848b2cb3..57d61221 100644
--- a/zen/http.cpp
+++ b/zen/http.cpp
@@ -492,7 +492,7 @@ bool zen::isValidEmail(const std::string& email)
             if (comp.empty() || !std::all_of(comp.begin(), comp.end(), [](char c)
         {
             const char printable[] = "!#$%&'*+-/=?^_`{|}~";
-                return isAsciiAlpha(c) || isDigit(c) || makeUnsigned(c) >= 128 ||
+                return isAsciiAlpha(c) || isDigit(c) || !isAsciiChar(c) ||
                        std::find(std::begin(printable), std::end(printable), c) != std::end(printable);
             }))
     return false;
@@ -507,7 +507,7 @@ bool zen::isValidEmail(const std::string& email)
 
         for (const std::string& comp : split(domain, '.', SplitType::ALLOW_EMPTY))
             if (comp.empty() || comp.size() > 63 ||
-            !std::all_of(comp.begin(), comp.end(), [](char c) { return isAsciiAlpha(c) ||isDigit(c) || makeUnsigned(c) >= 128 || c ==  '-'; }))
+            !std::all_of(comp.begin(), comp.end(), [](char c) { return isAsciiAlpha(c) ||isDigit(c) || !isAsciiChar(c) || c ==  '-'; }))
         return false;
     }
 
diff --git a/zen/legacy_compiler.cpp b/zen/legacy_compiler.cpp
index 3e3b7ba7..416993ed 100644
--- a/zen/legacy_compiler.cpp
+++ b/zen/legacy_compiler.cpp
@@ -5,12 +5,6 @@
 // *****************************************************************************
 
 #include "legacy_compiler.h"
-#include <charconv>
-//1. including this one in string_tools.h blows up VC++:
-//  "An internal error has occurred in the compiler. (compiler file 'd:\agent\_work\1\s\src\vctools\Compiler\Utc\src\p2\p2symtab.c', line 2618)"
-//2. using inside PCH: "fatal error C1076: compiler limit: internal heap limit reached"
-
-
 #if __cpp_lib_to_chars
     #error get rid of workarounds
 #endif
diff --git a/zen/legacy_compiler.h b/zen/legacy_compiler.h
index 13cdd8d0..16e22d03 100644
--- a/zen/legacy_compiler.h
+++ b/zen/legacy_compiler.h
@@ -12,8 +12,9 @@
 
 
 
-//https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations
+//https://en.cppreference.com/w/cpp/feature_test
 //https://en.cppreference.com/w/User:D41D8CD98F/feature_testing_macros
+//https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations
 //https://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html
 namespace std
 {
diff --git a/zen/open_ssl.cpp b/zen/open_ssl.cpp
index f436875b..f2b48fd9 100644
--- a/zen/open_ssl.cpp
+++ b/zen/open_ssl.cpp
@@ -628,7 +628,7 @@ private:
 zen::TlsContext::TlsContext(int socket, const Zstring& server, const Zstring* caCertFilePath) :
     pimpl_(std::make_unique<Impl>(socket, utfTo<std::string>(server), caCertFilePath)) {} //throw SysError
 zen::TlsContext::~TlsContext() {}
-size_t zen::TlsContext::tryRead (      void* buffer, size_t bytesToRead ) { return pimpl_->tryRead(buffer,  bytesToRead); } //throw SysError
+size_t zen::TlsContext::tryRead (      void* buffer, size_t bytesToRead ) { return pimpl_->tryRead (buffer,  bytesToRead); } //throw SysError
 size_t zen::TlsContext::tryWrite(const void* buffer, size_t bytesToWrite) { return pimpl_->tryWrite(buffer, bytesToWrite); } //throw SysError
 
 
diff --git a/zen/perf.h b/zen/perf.h
index 33005e9f..2598ea76 100644
--- a/zen/perf.h
+++ b/zen/perf.h
@@ -21,9 +21,9 @@
 
 /* Example: Aggregated function call time:
 
-    static zen::PerfTimer timer;
-    timer.resume();
-    ZEN_ON_SCOPE_EXIT(timer.pause());
+    static zen::PerfTimer perfTest(true); //startPaused
+    perfTest.resume();
+    ZEN_ON_SCOPE_EXIT(perfTest.pause());
 */
 
 namespace zen
@@ -41,6 +41,8 @@ namespace zen
 class StopWatch
 {
 public:
+    explicit StopWatch(bool startPaused = false) : paused_(startPaused) {}
+
     bool isPaused() const { return paused_; }
 
     void pause()
@@ -77,7 +79,7 @@ public:
     }
 
 private:
-    bool paused_ = false;
+    bool paused_;
     std::chrono::steady_clock::time_point startTime_ = std::chrono::steady_clock::now();
     std::chrono::nanoseconds elapsedUntilPause_{}; //std::chrono::duration is uninitialized by default! WTF! When will this stupidity end???
 };
@@ -86,10 +88,13 @@ private:
 class PerfTimer
 {
 public:
-    [[deprecated]] PerfTimer() {}
+    [[deprecated]] explicit PerfTimer(bool startPaused = false) : watch_(startPaused) {}
 
     ~PerfTimer() { if (!resultShown_) showResult(); }
 
+    void pause () { watch_.pause(); }
+    void resume() { watch_.resume(); }
+
     void showResult()
     {
         const bool wasRunning = !watch_.isPaused();
diff --git a/zen/recycler.cpp b/zen/recycler.cpp
index 28b2d6c1..9c463546 100644
--- a/zen/recycler.cpp
+++ b/zen/recycler.cpp
@@ -23,7 +23,7 @@ bool zen::recycleOrDeleteIfExists(const Zstring& itemPath) //throw FileError
     ZEN_ON_SCOPE_EXIT(g_object_unref(file);)
 
     GError* error = nullptr;
-    ZEN_ON_SCOPE_EXIT(if (error) ::g_error_free(error););
+    ZEN_ON_SCOPE_EXIT(if (error) ::g_error_free(error));
 
     if (!::g_file_trash(file, nullptr, &error))
     {
@@ -52,10 +52,9 @@ bool zen::recycleOrDeleteIfExists(const Zstring& itemPath) //throw FileError
 }
 
 
-/*
-We really need access to a similar function to check whether a directory supports trashing and emit a warning if it does not!
+/* We really need access to a similar function to check whether a directory supports trashing and emit a warning if it does not!
 
-The following function looks perfect, alas it is restricted to local files and to the implementation of GIO only:
+   The following function looks perfect, alas it is restricted to local files and to the implementation of GIO only:
 
     gboolean _g_local_file_has_trash_dir(const char* dirpath, dev_t dir_dev);
     See: http://www.netmite.com/android/mydroid/2.0/external/bluetooth/glib/gio/glocalfileinfo.h
@@ -67,5 +66,4 @@ The following function looks perfect, alas it is restricted to local files and t
                                            writable && parent_info->has_trash_dir);
 
     => We're NOT interested in whether the specified folder can be trashed, but whether it supports thrashing its child elements! (Only support, not actual write access!)
-    This renders G_FILE_ATTRIBUTE_ACCESS_CAN_TRASH useless for this purpose.
-*/
+    This renders G_FILE_ATTRIBUTE_ACCESS_CAN_TRASH useless for this purpose.               */
diff --git a/zen/scope_guard.h b/zen/scope_guard.h
index 846d5663..e97d3f0a 100644
--- a/zen/scope_guard.h
+++ b/zen/scope_guard.h
@@ -60,7 +60,8 @@ template <typename F> inline
 void runScopeGuardDestructor(F& fun, bool failed, std::integral_constant<ScopeGuardRunMode, ScopeGuardRunMode::onFail>) noexcept
 {
     if (failed)
-        try { fun(); } catch (...) { assert(false); }
+        try { fun(); }
+        catch (...) { assert(false); }
 }
 
 
@@ -71,9 +72,10 @@ public:
     explicit ScopeGuard(const F&  fun) : fun_(fun) {}
     explicit ScopeGuard(      F&& fun) : fun_(std::move(fun)) {}
 
-    ScopeGuard(ScopeGuard&& other) : fun_(std::move(other.fun_)),
-        exeptionCount_(other.exeptionCount_),
-        dismissed_(other.dismissed_) { other.dismissed_ = true; }
+    ScopeGuard(ScopeGuard&& tmp) :
+        fun_(std::move(tmp.fun_)),
+        exeptionCount_(tmp.exeptionCount_),
+        dismissed_(tmp.dismissed_) { tmp.dismissed_ = true; }
 
     ~ScopeGuard() noexcept(runMode == ScopeGuardRunMode::onFail)
     {
diff --git a/zen/serialize.h b/zen/serialize.h
index a34f91a7..6c57e4ee 100644
--- a/zen/serialize.h
+++ b/zen/serialize.h
@@ -11,21 +11,20 @@
 #include <cstdint>
 #include <stdexcept>
 #include "string_base.h"
+#include "sys_error.h"
 //keep header clean from specific stream implementations! (e.g.file_io.h)! used by abstract.h!
 
 
 namespace zen
 {
-//high-performance unformatted serialization (avoiding wxMemoryOutputStream/wxMemoryInputStream inefficiencies)
+/* high-performance unformatted serialization (avoiding wxMemoryOutputStream/wxMemoryInputStream inefficiencies)
 
-/*
 --------------------------
 |Binary Container Concept|
 --------------------------
 binary container for data storage: must support "basic" std::vector interface (e.g. std::vector<std::byte>, std::string, Zbase<char>)
-*/
 
-/*
+
 -------------------------------
 |Buffered Input Stream Concept|
 -------------------------------
@@ -49,8 +48,7 @@ struct BufferedOutputStream
 Optional: support stream-copying
 --------------------------------
     const IOCallback& notifyUnbufferedIO
-};
-*/
+};                                                                           */
 using IOCallback = std::function<void(int64_t bytesDelta)>; //throw X
 
 
@@ -65,8 +63,12 @@ template <class N, class BufferedOutputStream> void writeNumber   (BufferedOutpu
 template <class C, class BufferedOutputStream> void writeContainer(BufferedOutputStream& stream, const C& str);                   //noexcept
 template <         class BufferedOutputStream> void writeArray    (BufferedOutputStream& stream, const void* buffer, size_t len); //
 //----------------------------------------------------------------------
-class UnexpectedEndOfStreamError {};
-template <class N, class BufferedInputStream> N    readNumber   (BufferedInputStream& stream); //throw UnexpectedEndOfStreamError (corrupted data)
+struct SysErrorUnexpectedEos : public SysError
+{
+    SysErrorUnexpectedEos() : SysError(_("File content is corrupted.") + L" (unexpected end of stream)") {}
+};
+
+template <class N, class BufferedInputStream> N    readNumber   (BufferedInputStream& stream); //throw SysErrorUnexpectedEos (corrupted data)
 template <class C, class BufferedInputStream> C    readContainer(BufferedInputStream& stream); //
 template <         class BufferedInputStream> void readArray    (BufferedInputStream& stream, void* buffer, size_t len); //
 
@@ -220,40 +222,40 @@ void writeContainer(BufferedOutputStream& stream, const C& cont) //don't even co
 
 
 template <class BufferedInputStream> inline
-void readArray(BufferedInputStream& stream, void* buffer, size_t len) //throw UnexpectedEndOfStreamError
+void readArray(BufferedInputStream& stream, void* buffer, size_t len) //throw SysErrorUnexpectedEos
 {
     const size_t bytesRead = stream.read(buffer, len);
     assert(bytesRead <= len); //buffer overflow otherwise not always detected!
     if (bytesRead < len)
-        throw UnexpectedEndOfStreamError();
+        throw SysErrorUnexpectedEos();
 }
 
 
 template <class N, class BufferedInputStream> inline
-N readNumber(BufferedInputStream& stream) //throw UnexpectedEndOfStreamError
+N readNumber(BufferedInputStream& stream) //throw SysErrorUnexpectedEos
 {
     static_assert(IsArithmetic<N>::value || std::is_same_v<N, bool> || std::is_enum_v<N>);
     N num{};
-    readArray(stream, &num, sizeof(N)); //throw UnexpectedEndOfStreamError
+    readArray(stream, &num, sizeof(N)); //throw SysErrorUnexpectedEos
     return num;
 }
 
 
 template <class C, class BufferedInputStream> inline
-C readContainer(BufferedInputStream& stream) //throw UnexpectedEndOfStreamError
+C readContainer(BufferedInputStream& stream) //throw SysErrorUnexpectedEos
 {
     C cont;
-    auto strLength = readNumber<uint32_t>(stream); //throw UnexpectedEndOfStreamError
+    auto strLength = readNumber<uint32_t>(stream); //throw SysErrorUnexpectedEos
     if (strLength > 0)
     {
         try
         {
-            cont.resize(strLength); //throw std::length_error
+            cont.resize(strLength); //throw std::length_error, std::bad_alloc
         }
-        catch (std::length_error&) { throw UnexpectedEndOfStreamError(); } //most likely this is due to data corruption!
-        catch (   std::bad_alloc&) { throw UnexpectedEndOfStreamError(); } //
+        catch (std::length_error&) { throw SysErrorUnexpectedEos(); } //most likely this is due to data corruption!
+        catch (   std::bad_alloc&) { throw SysErrorUnexpectedEos(); } //
 
-        readArray(stream, &cont[0], sizeof(typename C::value_type) * strLength); //throw UnexpectedEndOfStreamError
+        readArray(stream, &cont[0], sizeof(typename C::value_type) * strLength); //throw SysErrorUnexpectedEos
     }
     return cont;
 }
diff --git a/zen/shell_execute.cpp b/zen/shell_execute.cpp
index c8779bb8..90ccfdf3 100644
--- a/zen/shell_execute.cpp
+++ b/zen/shell_execute.cpp
@@ -82,6 +82,7 @@ std::pair<int /*exit code*/, std::wstring> zen::consoleExecute(const Zstring& cm
 
     const int EC_CHILD_LAUNCH_FAILED = 120; //avoid 127: used by the system, e.g. failure to execute due to missing .so file
 
+    //use O_TMPFILE? sounds nice, but support is probably crap: https://github.com/libvips/libvips/issues/1151
     const int fdTempFile = ::open(tempFilePath.c_str(), O_CREAT | O_EXCL | O_RDWR | O_CLOEXEC,
                                   S_IRUSR | S_IWUSR); //0600
     if (fdTempFile == -1)
diff --git a/zen/stl_tools.h b/zen/stl_tools.h
index 5fd29b6b..7d071413 100644
--- a/zen/stl_tools.h
+++ b/zen/stl_tools.h
@@ -270,7 +270,7 @@ Num hashArray(ByteIterator first, ByteIterator last)
     static_assert(IsInteger<ValType>::value || std::is_same_v<ValType, char> || std::is_same_v<ValType, wchar_t>);
 
     FNV1aHash<Num> hash;
-    std::for_each(first, last, [&hash](ValType v) { hash.add(static_cast<Num>(v)); });
+    std::for_each(first, last, [&hash](ValType v) { hash.add(v); });
     return hash.get();
 }
 
diff --git a/zen/string_tools.h b/zen/string_tools.h
index eaf1a700..cfdb27bd 100644
--- a/zen/string_tools.h
+++ b/zen/string_tools.h
@@ -26,6 +26,7 @@ template <class Char> bool isWhiteSpace(Char c);
 template <class Char> bool isLineBreak (Char c);
 template <class Char> bool isDigit     (Char c); //not exactly the same as "std::isdigit" -> we consider '0'-'9' only!
 template <class Char> bool isHexDigit  (Char c);
+template <class Char> bool isAsciiChar (Char c);
 template <class Char> bool isAsciiAlpha(Char c);
 template <class S   > bool isAsciiString(const S& str);
 template <class Char> Char asciiToLower(Char c);
@@ -143,6 +144,13 @@ bool isHexDigit(Char c)
 
 
 template <class Char> inline
+bool isAsciiChar(Char c)
+{
+    return makeUnsigned(c) < 128;
+}
+
+
+template <class Char> inline
 bool isAsciiAlpha(Char c)
 {
     static_assert(std::is_same_v<Char, char> || std::is_same_v<Char, wchar_t>);
@@ -155,7 +163,7 @@ template <class S> inline
 bool isAsciiString(const S& str)
 {
     const auto* const first = strBegin(str);
-    return std::all_of(first, first + strLength(str), [](auto c) { return makeUnsigned(c) < 128; });
+    return std::all_of(first, first + strLength(str), [](auto c) { return isAsciiChar(c); });
 }
 
 
@@ -255,7 +263,7 @@ int compareString(const S& lhs, const T& rhs)
     const size_t lhsLen = strLength(lhs);
     const size_t rhsLen = strLength(rhs);
 
-    //length check *after* strcmpWithNulls(): we do care about natural ordering: e.g. for "compareString(makeUpperCopy(lhs), makeUpperCopy(rhs))"
+    //length check *after* strcmpWithNulls(): we do care about natural ordering: e.g. for "compareString(getUpperCase(lhs), getUpperCase(rhs))"
     if (const int rv = impl::strcmpWithNulls(strBegin(lhs), strBegin(rhs), std::min(lhsLen, rhsLen));
         rv != 0)
         return rv;
diff --git a/zen/string_traits.h b/zen/string_traits.h
index 69d76b44..76d601b3 100644
--- a/zen/string_traits.h
+++ b/zen/string_traits.h
@@ -99,11 +99,7 @@ ZEN_INIT_DETECT_MEMBER(length) //
 template <class S>
 class StringTraits
 {
-#if __cpp_lib_remove_cvref
     using CleanType       = std::remove_cvref_t<S>;
-#else
-    using CleanType       = std::remove_cv_t<std::remove_reference_t<S>>;
-#endif
     using NonArrayType    = std::remove_extent_t <CleanType>;
     using NonPtrType      = std::remove_pointer_t<NonArrayType>;
     using UndecoratedType = std::remove_cv_t     <NonPtrType>; //handle "const char* const"
diff --git a/zen/symlink_target.h b/zen/symlink_target.h
index 077fd4b3..59003284 100644
--- a/zen/symlink_target.h
+++ b/zen/symlink_target.h
@@ -17,8 +17,13 @@
 namespace zen
 {
 
-Zstring getSymlinkResolvedPath(const Zstring& linkPath); //throw FileError; Win: requires Vista or later!
-Zstring getSymlinkTargetRaw   (const Zstring& linkPath); //throw FileError
+struct SymlinkRawContent
+{
+    Zstring targetPath;
+};
+SymlinkRawContent getSymlinkRawContent(const Zstring& linkPath); //throw FileError
+
+Zstring getSymlinkResolvedPath(const Zstring& linkPath); //throw FileError
 }
 
 
@@ -34,7 +39,7 @@ Zstring getSymlinkTargetRaw   (const Zstring& linkPath); //throw FileError
 namespace
 {
 //retrieve raw target data of symlink or junction
-Zstring getSymlinkRawTargetString_impl(const Zstring& linkPath) //throw FileError
+zen::SymlinkRawContent getSymlinkRawContent_impl(const Zstring& linkPath) //throw FileError
 {
     using namespace zen;
     const size_t BUFFER_SIZE = 10000;
@@ -46,7 +51,7 @@ Zstring getSymlinkRawTargetString_impl(const Zstring& linkPath) //throw FileErro
     if (bytesWritten >= static_cast<ssize_t>(BUFFER_SIZE)) //detect truncation, not an error for readlink!
         throw FileError(replaceCpy(_("Cannot resolve symbolic link %x."), L"%x", fmtPath(linkPath)), formatSystemError("readlink", L"", L"Buffer truncated."));
 
-    return Zstring(&buffer[0], bytesWritten); //readlink does not append 0-termination!
+    return {Zstring(&buffer[0], bytesWritten)}; //readlink does not append 0-termination!
 }
 
 
@@ -65,7 +70,8 @@ Zstring getResolvedSymlinkPath_impl(const Zstring& linkPath) //throw FileError
 namespace zen
 {
 inline
-Zstring getSymlinkTargetRaw(const Zstring& linkPath) { return getSymlinkRawTargetString_impl(linkPath); }
+SymlinkRawContent getSymlinkRawContent(const Zstring& linkPath) { return getSymlinkRawContent_impl(linkPath); }
+
 
 inline
 Zstring getSymlinkResolvedPath(const Zstring& linkPath) { return getResolvedSymlinkPath_impl(linkPath); }
diff --git a/zen/system.cpp b/zen/system.cpp
index f39fae84..23e2c343 100644
--- a/zen/system.cpp
+++ b/zen/system.cpp
@@ -56,7 +56,7 @@ ComputerModel zen::getComputerModel() //throw FileError
                 const std::string stream = loadBinContainer<std::string>(filePath, nullptr /*notifyUnbufferedIO*/); //throw FileError
                 return utfTo<std::wstring>(trimCpy(stream));
             }
-            catch (const FileError& e) { throw SysError(e.toString()); } //errors should be further enriched by context info => SysError
+            catch (const FileError& e) { throw SysError(replaceCpy(e.toString(), L"\n\n", L'\n')); } //errors should be further enriched by context info => SysError
         };
         cm.model  = tryGetInfo("/sys/devices/virtual/dmi/id/product_name"); //throw SysError
         cm.vendor = tryGetInfo("/sys/devices/virtual/dmi/id/sys_vendor");   //
@@ -103,7 +103,7 @@ std::wstring zen::getOsDescription() //throw FileError
         {
             releaseInfo = loadBinContainer<std::string>("/etc/os-release", nullptr /*notifyUnbufferedIO*/); //throw FileError
         }
-        catch (const FileError& e) { throw SysError(e.toString()); } //further enrich with context info => SysError
+        catch (const FileError& e) { throw SysError(replaceCpy(e.toString(), L"\n\n", L'\n')); } //errors should be further enriched by context info => SysError
 
         std::string osName;
         std::string osVersion;
diff --git a/zen/zstring.cpp b/zen/zstring.cpp
index 690f004b..b78bc118 100644
--- a/zen/zstring.cpp
+++ b/zen/zstring.cpp
@@ -14,7 +14,7 @@
 using namespace zen;
 
 
-Zstring makeUpperCopy(const Zstring& str)
+Zstring getUpperCase(const Zstring& str)
 {
     //fast pre-check:
     if (isAsciiString(str)) //perf: in the range of 3.5ns
@@ -81,7 +81,7 @@ Zstring replaceCpyAsciiNoCase(const Zstring& str, const Zstring& oldTerm, const
 
     for (size_t pos = 0;;)
     {
-        const size_t posFound = std::search(str.begin() + pos, str.end(), //can't use makeUpperCopy(): input/output sizes may differ!
+        const size_t posFound = std::search(str.begin() + pos, str.end(), //can't use getUpperCase(): input/output sizes may differ!
                                             oldTerm.begin(), oldTerm.end(),
         [](Zchar charL, Zchar charR) { return asciiToUpper(charL) == asciiToUpper(charR); }) - str.begin();
 
@@ -100,8 +100,7 @@ Zstring replaceCpyAsciiNoCase(const Zstring& str, const Zstring& oldTerm, const
 }
 
 
-/*
-https://docs.microsoft.com/de-de/windows/desktop/Intl/handling-sorting-in-your-applications
+/* https://docs.microsoft.com/de-de/windows/desktop/Intl/handling-sorting-in-your-applications
 
 Perf test: compare strings 10 mio times; 64 bit build
 -----------------------------------------------------
@@ -120,8 +119,8 @@ OS X (UTF8 char)
  856 ns | CFStringCreateWithCString       + CFStringCompare(kCFCompareCaseInsensitive)
 1110 ns | CFStringCreateWithCStringNoCopy + CFStringCompare(kCFCompareCaseInsensitive)
 ________________________
-time per call | function
-*/
+time per call | function                                                   */
+
 int compareNativePath(const Zstring& lhs, const Zstring& rhs)
 {
     assert(lhs.find(Zchar('\0')) == Zstring::npos); //don't expect embedded nulls!
diff --git a/zen/zstring.h b/zen/zstring.h
index e262603e..adfd671b 100644
--- a/zen/zstring.h
+++ b/zen/zstring.h
@@ -28,7 +28,7 @@ using Zstringc = zen::Zbase<char>;
 // - different UTF-8 encoding length of upper-case chars
 // - different number of upper case chars (e.g. "ߢ => "SS" on macOS)
 // - output is Unicode-normalized
-Zstring makeUpperCopy(const Zstring& str);
+Zstring getUpperCase(const Zstring& str);
 
 //Windows, Linux: precomposed
 //macOS: decomposed
@@ -43,11 +43,11 @@ Zstring replaceCpyAsciiNoCase(const Zstring& str, const Zstring& oldTerm, const
 
 //------------------------------------------------------------------------------------------
 
-inline bool equalNoCase(const Zstring& lhs, const Zstring& rhs) { return makeUpperCopy(lhs) == makeUpperCopy(rhs); }
+inline bool equalNoCase(const Zstring& lhs, const Zstring& rhs) { return getUpperCase(lhs) == getUpperCase(rhs); }
 
 struct ZstringNoCase //use as STL container key: avoid needless upper-case conversions during std::map<>::find()
 {
-    ZstringNoCase(const Zstring& str) : upperCase(makeUpperCopy(str)) {}
+    ZstringNoCase(const Zstring& str) : upperCase(getUpperCase(str)) {}
     Zstring upperCase;
 
     std::strong_ordering operator<=>(const ZstringNoCase& other) const = default;