Improvements for log files (#22)

* Improvements for log files
 - Added exec name to log files
 - Added DXVK_LOG_PATH environment variable to specify the log folder
* Remove .exe from log name
* log: add log level none
* log: corrected type for string position

src/util/log/log.cpp

@@ -5,8 +5,22 @@
 namespace dxvk {
   
   Logger::Logger(const std::string& file_name)
-  : m_minLevel(getMinLogLevel()),
+  : m_minLevel(getMinLogLevel())
-    m_fileStream(file_name) { }
+  {
+    if (m_minLevel == LogLevel::None)
+        return;
+    
+    std::string path = env::getEnvVar(L"DXVK_LOG_PATH");
+    std::string file = path;
+    if (!file.empty() && *file.rbegin() != '/')
+      file += '/';
+    std::string name = env::getExeName();
+    auto extp = name.find_last_of('.');
+    if (extp != std::string::npos && name.substr(extp +1) == "exe")
+      name.erase(extp);
+    file += name + "_";
+    m_fileStream = std::ofstream(file + file_name);
+  }
   
   
   Logger::~Logger() { }
@@ -53,12 +67,13 @@ namespace dxvk {
   
   
   LogLevel Logger::getMinLogLevel() {
-    const std::array<std::pair<const char*, LogLevel>, 5> logLevels = {{
+    const std::array<std::pair<const char*, LogLevel>, 6> logLevels = {{
       { "trace", LogLevel::Trace },
       { "debug", LogLevel::Debug },
       { "info",  LogLevel::Info  },
       { "warn",  LogLevel::Warn  },
       { "error", LogLevel::Error },
+      { "none",  LogLevel::None  },
     }};
     
     const std::string logLevelStr = env::getEnvVar(L"DXVK_LOG_LEVEL");

src/util/log/log.h

@@ -13,6 +13,7 @@ namespace dxvk {
     Info  = 2,
     Warn  = 3,
     Error = 4,
+    None  = 5,
   };
   
   /**