Debug.h (2881B)
1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ 2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */ 3 /* This Source Code Form is subject to the terms of the Mozilla Public 4 * License, v. 2.0. If a copy of the MPL was not distributed with this 5 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */ 6 7 #ifndef mozilla_glue_Debug_h 8 #define mozilla_glue_Debug_h 9 10 #include "mozilla/Attributes.h" // For MOZ_FORMAT_PRINTF 11 #include "mozilla/Types.h" // For MFBT_API 12 13 #include <cstdarg> 14 #include <sstream> 15 16 /* This header file intends to supply debugging utilities for use in code 17 * that cannot use XPCOM debugging facilities like nsDebug.h. 18 * e.g. mozglue, browser/app 19 * 20 * NB: printf_stderr() is in the global namespace, so include this file with 21 * care; avoid including from header files. 22 */ 23 24 #ifdef __cplusplus 25 extern "C" { 26 #endif // __cplusplus 27 28 /** 29 * printf_stderr(...) is much like fprintf(stderr, ...), except that: 30 * - on Android and Firefox OS, *instead* of printing to stderr, it 31 * prints to logcat. (Newlines in the string lead to multiple lines 32 * of logcat, but each function call implicitly completes a line even 33 * if the string does not end with a newline.) 34 * - on Windows, if a debugger is present, it calls OutputDebugString 35 * in *addition* to writing to stderr 36 */ 37 MFBT_API void printf_stderr(const char* aFmt, ...) MOZ_FORMAT_PRINTF(1, 2); 38 39 /** 40 * Same as printf_stderr, but taking va_list instead of varargs 41 */ 42 MFBT_API void vprintf_stderr(const char* aFmt, va_list aArgs) 43 MOZ_FORMAT_PRINTF(1, 0); 44 45 /** 46 * fprintf_stderr is like fprintf, except that if its file argument 47 * is stderr, it invokes printf_stderr instead. 48 * 49 * This is useful for general debugging code that logs information to a 50 * file, but that you would like to be useful on Android and Firefox OS. 51 * If you use fprintf_stderr instead of fprintf in such debugging code, 52 * then callers can pass stderr to get logging that works on Android and 53 * Firefox OS (and also the other side-effects of using printf_stderr). 54 * 55 * Code that is structured this way needs to be careful not to split a 56 * line of output across multiple calls to fprintf_stderr, since doing 57 * so will cause it to appear in multiple lines in logcat output. 58 * (Producing multiple lines at once is fine.) 59 */ 60 MFBT_API void fprintf_stderr(FILE* aFile, const char* aFmt, ...) 61 MOZ_FORMAT_PRINTF(2, 3); 62 63 /* 64 * print_stderr and fprint_stderr are like printf_stderr and fprintf_stderr, 65 * except they deal with Android logcat line length limitations. They do this 66 * by printing individual lines out of the provided stringstream using separate 67 * calls to logcat. 68 */ 69 MFBT_API void print_stderr(std::stringstream& aStr); 70 MFBT_API void fprint_stderr(FILE* aFile, std::stringstream& aStr); 71 72 #ifdef __cplusplus 73 } 74 #endif // __cplusplus 75 76 #endif // mozilla_glue_Debug_h