/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

// Based on chromium's base/logging.cc, with a lot of simplifications.

#include "base/logging.h"

#include "base/immediate_crash.h"
#include "base/posix/safe_strerror.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "build/build_config.h"

#if BUILDFLAG(IS_WIN)
#include <windows.h>
#endif

#include <cstdio>

namespace logging {

static int g_min_log_level = 0;

// A log message handler that gets notified of every log message we process.
LogMessageHandlerFunction g_log_message_handler = nullptr;

void SetLogMessageHandler(LogMessageHandlerFunction handler) {
  g_log_message_handler = handler;
}

LogMessageHandlerFunction GetLogMessageHandler() {
  return g_log_message_handler;
}

bool ShouldCreateLogMessage(int severity) {
  return severity >= g_min_log_level;
}

#if BUILDFLAG(IS_WIN)
// This has already been defined in the header, but defining it again as DWORD
// ensures that the type used in the header is equivalent to DWORD. If not,
// the redefinition is a compile error.
typedef DWORD SystemErrorCode;
#endif

SystemErrorCode GetLastSystemErrorCode() {
#if BUILDFLAG(IS_WIN)
  return ::GetLastError();
#elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
  return errno;
#endif
}

// For LOGGING_ERROR and above, always print to stderr.
const int kAlwaysPrintErrorLevel = LOGGING_ERROR;

static bool ShouldLogToStderr(int severity) {
  return severity >= kAlwaysPrintErrorLevel;
}

const char* const log_severity_names[] = {"INFO", "WARNING", "ERROR", "FATAL"};
static_assert(LOGGING_NUM_SEVERITIES == std::size(log_severity_names),
              "Incorrect number of log_severity_names");

const char* log_severity_name(int severity) {
  if (severity >= 0 && severity < LOGGING_NUM_SEVERITIES) {
    return log_severity_names[severity];
  }
  return "UNKNOWN";
}

LogMessage::LogMessage(const char* file, int line, LogSeverity severity)
    : severity_(severity), file_(file), line_(line) {
  // Don't let actions from this method affect the system error after returning.
  base::ScopedClearLastError scoped_clear_last_error;

  // Most logging initializes `file` from __FILE__. This isn't true for
  // base::Location::Current() which already does the stripping (and is used
  // for some logging, especially CHECKs).
  // Note(moz): Upstream code mitigates this with a hack, but for our mozilla
  //            vendoring we don't, hence the long filenames shown in logs
  //            except for CHECKs.

  {
    stream_ << "[zucchini:";
    if (severity_ >= 0) {
      stream_ << log_severity_name(severity_);
    } else {
      stream_ << "VERBOSE" << -severity_;
    }
    stream_ << ":" << file << ":" << line << "] ";
  }
  message_start_ = stream_.str().length();
}

LogMessage::~LogMessage() {
  // Don't let actions from this method affect the system error after returning.
  base::ScopedClearLastError scoped_clear_last_error;

  // Note(moz): Contrary to upstream code, we do not add an extra newline
  //            before forwarding the message. This is the format expected by
  //            the updater's log function.
  std::string str(stream_.str());

  // Give any log message handler first dibs on the message.
  bool handled = g_log_message_handler &&
    g_log_message_handler(severity_, file_, line_, message_start_, str);
  if (!handled) {
    if (ShouldLogToStderr(severity_)) {
      fputs(str.c_str(), stderr);
      fputc('\n', stderr);
    }
    else {
      // Contrary to fputs(), puts() already writes a newline character
      puts(str.c_str());
    }
  }

  if (severity_ == LOGGING_FATAL) {
    base::ImmediateCrash();
  }
}

BASE_EXPORT std::string SystemErrorCodeToString(SystemErrorCode error_code) {
#if BUILDFLAG(IS_WIN)
  LPWSTR msgbuf = nullptr;
  DWORD len = ::FormatMessageW(
      FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
          FORMAT_MESSAGE_IGNORE_INSERTS,
      nullptr, error_code, 0, reinterpret_cast<LPWSTR>(&msgbuf), 0, nullptr);
  if (len) {
    std::u16string message = base::WideToUTF16(msgbuf);
    ::LocalFree(msgbuf);
    msgbuf = nullptr;
    // Messages returned by system end with line breaks.
    return base::UTF16ToUTF8(base::CollapseWhitespace(message, true)) +
           base::StringPrintf(" (0x%lX)", error_code);
  }
  return base::StringPrintf("Error (0x%lX) while retrieving error. (0x%lX)",
                            GetLastError(), error_code);
#elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
  return base::safe_strerror(error_code) +
         base::StringPrintf(" (%d)", error_code);
#endif  // BUILDFLAG(IS_WIN)
}

#if BUILDFLAG(IS_WIN)
Win32ErrorLogMessage::Win32ErrorLogMessage(const char* file,
                                           int line,
                                           LogSeverity severity,
                                           SystemErrorCode err)
    : LogMessage(file, line, severity), err_(err) {}

Win32ErrorLogMessage::~Win32ErrorLogMessage() {
  // Don't let actions from this method affect the system error after returning.
  base::ScopedClearLastError scoped_clear_last_error;

  stream() << ": " << SystemErrorCodeToString(err_);
}

#elif BUILDFLAG(IS_POSIX)
ErrnoLogMessage::ErrnoLogMessage(const char* file,
                                 int line,
                                 LogSeverity severity,
                                 SystemErrorCode err)
    : LogMessage(file, line, severity), err_(err) {}

ErrnoLogMessage::~ErrnoLogMessage() {
  // Don't let actions from this method affect the system error after returning.
  base::ScopedClearLastError scoped_clear_last_error;

  stream() << ": " << SystemErrorCodeToString(err_);
}

#endif  // BUILDFLAG(IS_WIN)

}  // namespace logging