1 files changed, 76 insertions, 0 deletions
diff --git a/mozglue/misc/Debug.h b/mozglue/misc/Debug.h
new file mode 100644
index 0000000000..43380878b9
--- /dev/null
+++ b/mozglue/misc/Debug.h
@@ -0,0 +1,76 @@
+/* -*- 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