gecko-dev/mozglue/misc/Debug.h

77 lines
2.8 KiB
C++

/* -*- 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 https://mozilla.org/MPL/2.0/. */
#ifndef mozilla_glue_Debug_h
#define mozilla_glue_Debug_h
#include "mozilla/Attributes.h" // For MOZ_FORMAT_PRINTF
#include "mozilla/Types.h" // For MFBT_API
#include <cstdarg>
#include <sstream>
/* This header file intends to supply debugging utilities for use in code
* that cannot use XPCOM debugging facilities like nsDebug.h.
* e.g. mozglue, browser/app
*
* NB: printf_stderr() is in the global namespace, so include this file with
* care; avoid including from header files.
*/
#ifdef __cplusplus
extern "C" {
#endif // __cplusplus
/**
* printf_stderr(...) is much like fprintf(stderr, ...), except that:
* - on Android and Firefox OS, *instead* of printing to stderr, it
* prints to logcat. (Newlines in the string lead to multiple lines
* of logcat, but each function call implicitly completes a line even
* if the string does not end with a newline.)
* - on Windows, if a debugger is present, it calls OutputDebugString
* in *addition* to writing to stderr
*/
MFBT_API void printf_stderr(const char* aFmt, ...) MOZ_FORMAT_PRINTF(1, 2);
/**
* Same as printf_stderr, but taking va_list instead of varargs
*/
MFBT_API void vprintf_stderr(const char* aFmt, va_list aArgs)
MOZ_FORMAT_PRINTF(1, 0);
/**
* fprintf_stderr is like fprintf, except that if its file argument
* is stderr, it invokes printf_stderr instead.
*
* This is useful for general debugging code that logs information to a
* file, but that you would like to be useful on Android and Firefox OS.
* If you use fprintf_stderr instead of fprintf in such debugging code,
* then callers can pass stderr to get logging that works on Android and
* Firefox OS (and also the other side-effects of using printf_stderr).
*
* Code that is structured this way needs to be careful not to split a
* line of output across multiple calls to fprintf_stderr, since doing
* so will cause it to appear in multiple lines in logcat output.
* (Producing multiple lines at once is fine.)
*/
MFBT_API void fprintf_stderr(FILE* aFile, const char* aFmt, ...)
MOZ_FORMAT_PRINTF(2, 3);
/*
* print_stderr and fprint_stderr are like printf_stderr and fprintf_stderr,
* except they deal with Android logcat line length limitations. They do this
* by printing individual lines out of the provided stringstream using separate
* calls to logcat.
*/
MFBT_API void print_stderr(std::stringstream& aStr);
MFBT_API void fprint_stderr(FILE* aFile, std::stringstream& aStr);
#ifdef __cplusplus
}
#endif // __cplusplus
#endif // mozilla_glue_Debug_h