Squashed 'gitstatus/' content from commit 6b9ba17

git-subtree-dir: gitstatus
git-subtree-split: 6b9ba179c6655286c4c399e7926d5098dd6bd706

src/logging.h

@@ -0,0 +1,124 @@
+// Copyright 2019 Roman Perepelitsa.
+//
+// This file is part of GitStatus.
+//
+// GitStatus is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// GitStatus is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with GitStatus. If not, see <https://www.gnu.org/licenses/>.
+
+#ifndef ROMKATV_GITSTATUS_LOGGING_H_
+#define ROMKATV_GITSTATUS_LOGGING_H_
+
+#include <cstdlib>
+#include <memory>
+#include <ostream>
+#include <sstream>
+
+#define LOG(severity) LOG_I(severity)
+
+#define LOG_I(severity)                                                                            \
+  (::gitstatus::severity < ::gitstatus::g_min_log_level)                                           \
+      ? static_cast<void>(0)                                                                       \
+      : ::gitstatus::internal_logging::Assignable() =                                              \
+            ::gitstatus::internal_logging::LogStream<::gitstatus::severity>(__FILE__, __LINE__,    \
+                                                                            ::gitstatus::severity) \
+                .ref()
+
+namespace gitstatus {
+
+enum LogLevel {
+  DEBUG,
+  INFO,
+  WARN,
+  ERROR,
+  FATAL,
+};
+
+const char* LogLevelStr(LogLevel lvl);
+bool ParseLogLevel(const char* s, LogLevel& lvl);
+
+extern LogLevel g_min_log_level;
+
+namespace internal_logging {
+
+struct Assignable {
+  template <class T>
+  void operator=(const T&) const {}
+};
+
+class LogStreamBase {
+ public:
+  LogStreamBase(const char* file, int line, LogLevel lvl);
+
+  LogStreamBase& ref() { return *this; }
+  std::ostream& strm() { return *strm_; }
+  int stashed_errno() const { return errno_; }
+
+ protected:
+  void Flush();
+
+ private:
+  int errno_;
+  const char* file_;
+  int line_;
+  const char* lvl_;
+  std::unique_ptr<std::ostringstream> strm_;
+};
+
+template <LogLevel>
+class LogStream : public LogStreamBase {
+ public:
+  using LogStreamBase::LogStreamBase;
+  ~LogStream() { this->Flush(); }
+};
+
+template <>
+class LogStream<FATAL> : public LogStreamBase {
+ public:
+  using LogStreamBase::LogStreamBase;
+  ~LogStream() __attribute__((noreturn)) {
+    this->Flush();
+    std::abort();
+  }
+};
+
+template <class T>
+LogStreamBase& operator<<(LogStreamBase& strm, const T& val) {
+  strm.strm() << val;
+  return strm;
+}
+
+inline LogStreamBase& operator<<(LogStreamBase& strm, std::ostream& (*manip)(std::ostream&)) {
+  strm.strm() << manip;
+  return strm;
+}
+
+struct Errno {
+  int err;
+};
+
+std::ostream& operator<<(std::ostream& strm, Errno e);
+
+struct StashedErrno {};
+
+inline LogStreamBase& operator<<(LogStreamBase& strm, StashedErrno) {
+  return strm << Errno{strm.stashed_errno()};
+}
+
+}  // namespace internal_logging
+
+inline internal_logging::Errno Errno(int err) { return {err}; }
+inline internal_logging::StashedErrno Errno() { return {}; }
+
+}  // namespace gitstatus
+
+#endif  // ROMKATV_GITSTATUS_LOGGING_H_