fix audio desync for realsies, stderr to log.txt

src/log.cpp

@@ -1,16 +1,26 @@
 #include "log.hpp"
 
+#include <array>
 #include <print>
 
+#include "path_.hpp"
 #include "sdl.hpp"
 #include "time_.hpp"
 
+#if _WIN32
+  #include <fcntl.h>
+  #include <io.h>
+#else
+  #include <unistd.h>
+#endif
+
 using namespace anm2ed::util;
 
 namespace anm2ed
 {
   void Logger::write_raw(const std::string& message)
   {
+    std::lock_guard lock(mutex);
     std::println("{}", message);
     if (file.is_open()) file << message << '\n' << std::flush;
   }
@@ -26,7 +36,105 @@ namespace anm2ed
   void Logger::error(const std::string& message) { write(ERROR, message); }
   void Logger::fatal(const std::string& message) { write(FATAL, message); }
   void Logger::command(const std::string& message) { write(COMMAND, message); }
-  void Logger::open(const std::filesystem::path& path) { file.open(path, std::ios::out | std::ios::app); }
+
+  void Logger::stderr_pump()
+  {
+    std::string pending{};
+    std::array<char, 512> buffer{};
+    while (isStderrRedirecting)
+    {
+      int readBytes{};
+#if _WIN32
+      readBytes = _read(stderrPipeReadFd, buffer.data(), (unsigned int)buffer.size());
+#else
+      readBytes = (int)read(stderrPipeReadFd, buffer.data(), buffer.size());
+#endif
+      if (readBytes <= 0) break;
+
+      pending.append(buffer.data(), (std::size_t)readBytes);
+
+      std::size_t lineEnd{};
+      while ((lineEnd = pending.find('\n')) != std::string::npos)
+      {
+        auto line = pending.substr(0, lineEnd);
+        if (!line.empty() && line.back() == '\r') line.pop_back();
+        if (!line.empty()) write_raw(line);
+        pending.erase(0, lineEnd + 1);
+      }
+    }
+
+    if (!pending.empty()) write_raw(pending);
+  }
+
+  void Logger::stderr_redirect_start()
+  {
+    if (isStderrRedirecting) return;
+
+    int pipeFds[2]{-1, -1};
+#if _WIN32
+    if (_pipe(pipeFds, 4096, _O_BINARY) != 0) return;
+    stderrOriginalFd = _dup(_fileno(stderr));
+    if (stderrOriginalFd < 0 || _dup2(pipeFds[1], _fileno(stderr)) != 0)
+    {
+      _close(pipeFds[0]);
+      _close(pipeFds[1]);
+      return;
+    }
+    _close(pipeFds[1]);
+#else
+    if (pipe(pipeFds) != 0) return;
+    stderrOriginalFd = dup(fileno(stderr));
+    if (stderrOriginalFd < 0 || dup2(pipeFds[1], fileno(stderr)) < 0)
+    {
+      close(pipeFds[0]);
+      close(pipeFds[1]);
+      return;
+    }
+    close(pipeFds[1]);
+#endif
+
+    std::setvbuf(stderr, nullptr, _IONBF, 0);
+
+    stderrPipeReadFd = pipeFds[0];
+    isStderrRedirecting = true;
+    stderrThread = std::thread([this]() { stderr_pump(); });
+  }
+
+  void Logger::stderr_redirect_stop()
+  {
+    if (!isStderrRedirecting) return;
+    isStderrRedirecting = false;
+
+    if (stderrOriginalFd >= 0)
+    {
+#if _WIN32
+      _dup2(stderrOriginalFd, _fileno(stderr));
+      _close(stderrOriginalFd);
+#else
+      dup2(stderrOriginalFd, fileno(stderr));
+      close(stderrOriginalFd);
+#endif
+      stderrOriginalFd = -1;
+    }
+
+    if (stderrPipeReadFd >= 0)
+    {
+#if _WIN32
+      _close(stderrPipeReadFd);
+#else
+      close(stderrPipeReadFd);
+#endif
+      stderrPipeReadFd = -1;
+    }
+
+    if (stderrThread.joinable()) stderrThread.join();
+  }
+
+  void Logger::open(const std::filesystem::path& path)
+  {
+    file.open(path, std::ios::out | std::ios::app);
+    stderr_redirect_start();
+  }
 
   std::filesystem::path Logger::path() { return sdl::preferences_directory_get() / "log.txt"; }
 
@@ -39,6 +147,7 @@ namespace anm2ed
   Logger::~Logger()
   {
     info("Exiting Anm2Ed");
+    stderr_redirect_stop();
     if (file.is_open()) file.close();
   }
 }