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authorKarsten Blees <karsten.blees@gmail.com>2014-07-12 02:05:03 +0200
committerJunio C Hamano <gitster@pobox.com>2014-07-13 21:25:20 -0700
commite05bed960d3bf3bcfd0f27ab882df3da93e118ed (patch)
treed9ce58a75230ab10a0e2caff5cb0d7787a3a5f1b /trace.h
parent66f66c596fa2b4e7d4c00575a5731d33ab28d4ed (diff)
downloadgit-e05bed960d3bf3bcfd0f27ab882df3da93e118ed.tar.gz
trace: add 'file:line' to all trace output
This is useful to see where trace output came from. Add 'const char *file, int line' parameters to the printing functions and rename them to *_fl. Add trace_printf* and trace_strbuf macros resolving to the *_fl functions and let the preprocessor fill in __FILE__ and __LINE__. As the trace_printf* functions take a variable number of arguments, this requires variadic macros (i.e. '#define foo(...) foo_impl(__VA_ARGS__)'. Though part of C99, it is unclear whether older compilers support this. Thus keep the old functions and only enable variadic macros for GNUC and MSVC 2005+ (_MSC_VER 1400). This has the nice side effect that the old C-style declarations serve as documentation how the macros are to be used. Print 'file:line ' as prefix to each trace line. Align the remaining trace output at column 40 to accommodate 18 char file names + 4 digit line number (currently there are 30 *.c files of length 18 and just 11 of 19). Trace output from longer source files (e.g. builtin/receive-pack.c) will not be aligned. Signed-off-by: Karsten Blees <blees@dcon.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'trace.h')
-rw-r--r--trace.h62
1 files changed, 62 insertions, 0 deletions
diff --git a/trace.h b/trace.h
index b4800e7461..7a5ba2e61c 100644
--- a/trace.h
+++ b/trace.h
@@ -17,6 +17,8 @@ extern void trace_repo_setup(const char *prefix);
extern int trace_want(struct trace_key *key);
extern void trace_disable(struct trace_key *key);
+#ifndef HAVE_VARIADIC_MACROS
+
__attribute__((format (printf, 1, 2)))
extern void trace_printf(const char *format, ...);
@@ -28,4 +30,64 @@ extern void trace_argv_printf(const char **argv, const char *format, ...);
extern void trace_strbuf(struct trace_key *key, const struct strbuf *data);
+#else
+
+/*
+ * Macros to add file:line - see above for C-style declarations of how these
+ * should be used.
+ */
+
+/*
+ * TRACE_CONTEXT may be set to __FUNCTION__ if the compiler supports it. The
+ * default is __FILE__, as it is consistent with assert(), and static function
+ * names are not necessarily unique.
+ *
+ * __FILE__ ":" __FUNCTION__ doesn't work with GNUC, as __FILE__ is supplied
+ * by the preprocessor as a string literal, and __FUNCTION__ is filled in by
+ * the compiler as a string constant.
+ */
+#ifndef TRACE_CONTEXT
+# define TRACE_CONTEXT __FILE__
+#endif
+
+/*
+ * Note: with C99 variadic macros, __VA_ARGS__ must include the last fixed
+ * parameter ('format' in this case). Otherwise, a call without variable
+ * arguments will have a surplus ','. E.g.:
+ *
+ * #define foo(format, ...) bar(format, __VA_ARGS__)
+ * foo("test");
+ *
+ * will expand to
+ *
+ * bar("test",);
+ *
+ * which is invalid (note the ',)'). With GNUC, '##__VA_ARGS__' drops the
+ * comma, but this is non-standard.
+ */
+
+#define trace_printf(...) \
+ trace_printf_key_fl(TRACE_CONTEXT, __LINE__, NULL, __VA_ARGS__)
+
+#define trace_printf_key(key, ...) \
+ trace_printf_key_fl(TRACE_CONTEXT, __LINE__, key, __VA_ARGS__)
+
+#define trace_argv_printf(argv, ...) \
+ trace_argv_printf_fl(TRACE_CONTEXT, __LINE__, argv, __VA_ARGS__)
+
+#define trace_strbuf(key, data) \
+ trace_strbuf_fl(TRACE_CONTEXT, __LINE__, key, data)
+
+/* backend functions, use non-*fl macros instead */
+__attribute__((format (printf, 4, 5)))
+extern void trace_printf_key_fl(const char *file, int line, struct trace_key *key,
+ const char *format, ...);
+__attribute__((format (printf, 4, 5)))
+extern void trace_argv_printf_fl(const char *file, int line, const char **argv,
+ const char *format, ...);
+extern void trace_strbuf_fl(const char *file, int line, struct trace_key *key,
+ const struct strbuf *data);
+
+#endif /* HAVE_VARIADIC_MACROS */
+
#endif /* TRACE_H */