Merge commit '1531d6e543' as 'gitstatus'

gitstatus/src/logging.cc

@@ -0,0 +1,139 @@
+// 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/>.
+
+#include "logging.h"
+
+#include <pthread.h>
+#include <time.h>
+
+#include <cerrno>
+#include <cstdio>
+#include <cstring>
+#include <ctime>
+#include <mutex>
+#include <string>
+
+namespace gitstatus {
+
+namespace internal_logging {
+
+namespace {
+
+std::mutex g_log_mutex;
+
+constexpr char kHexLower[] = {'0', '1', '2', '3', '4', '5', '6', '7',
+                              '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
+
+void FormatThreadId(char (&out)[2 * sizeof(std::uintptr_t) + 1]) {
+  std::uintptr_t tid = (std::uintptr_t)pthread_self();
+  char* p = out + sizeof(out) - 1;
+  *p = 0;
+  do {
+    --p;
+    *p = kHexLower[tid & 0xF];
+    tid >>= 4;
+  } while (p != out);
+}
+
+void FormatCurrentTime(char (&out)[64]) {
+  std::time_t time = std::time(nullptr);
+  struct tm tm;
+  if (localtime_r(&time, &tm) != &tm || std::strftime(out, sizeof(out), "%F %T", &tm) == 0) {
+    std::strcpy(out, "undef");
+  }
+}
+
+}  // namespace
+
+LogStreamBase::LogStreamBase(const char* file, int line, LogLevel lvl)
+    : errno_(errno), file_(file), line_(line), lvl_(LogLevelStr(lvl)) {
+  strm_ = std::make_unique<std::ostringstream>();
+}
+
+void LogStreamBase::Flush() {
+  {
+    std::string msg = strm_->str();
+    char tid[2 * sizeof(std::uintptr_t) + 1];
+    FormatThreadId(tid);
+    char time[64];
+    FormatCurrentTime(time);
+
+    std::unique_lock<std::mutex> lock(g_log_mutex);
+    std::fprintf(stderr, "[%s %s %s %s:%d] %s\n", time, tid, lvl_, file_, line_, msg.c_str());
+  }
+  strm_.reset();
+  errno = errno_;
+}
+
+std::ostream& operator<<(std::ostream& strm, Errno e) {
+  // GNU C Library uses a buffer of 1024 characters for strerror(). Mimic to avoid truncations.
+  char buf[1024];
+  auto x = strerror_r(e.err, buf, sizeof(buf));
+  // There are two versions of strerror_r with different semantics. We can figure out which
+  // one we've got by looking at the result type.
+  if (std::is_same<decltype(x), int>::value) {
+    // XSI-compliant version.
+    strm << (x ? "unknown error" : buf);
+  } else if (std::is_same<decltype(x), char*>::value) {
+    // GNU-specific version.
+    strm << x;
+  } else {
+    // Something else entirely.
+    strm << "unknown error";
+  }
+  return strm;
+}
+
+}  // namespace internal_logging
+
+LogLevel g_min_log_level = INFO;
+
+const char* LogLevelStr(LogLevel lvl) {
+  switch (lvl) {
+    case DEBUG:
+      return "DEBUG";
+    case INFO:
+      return "INFO";
+    case WARN:
+      return "WARN";
+    case ERROR:
+      return "ERROR";
+    case FATAL:
+      return "FATAL";
+  }
+  return "UNKNOWN";
+}
+
+bool ParseLogLevel(const char* s, LogLevel& lvl) {
+  if (!s)
+    return false;
+  else if (!std::strcmp(s, "DEBUG"))
+    lvl = DEBUG;
+  else if (!std::strcmp(s, "INFO"))
+    lvl = INFO;
+  else if (!std::strcmp(s, "WARN"))
+    lvl = WARN;
+  else if (!std::strcmp(s, "ERROR"))
+    lvl = ERROR;
+  else if (!std::strcmp(s, "FATAL"))
+    lvl = FATAL;
+  else
+    return false;
+  return true;
+}
+
+}  // namespace gitstatus