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git/trace.h
Jeff King 323598387d pkt-line: support tracing verbatim pack contents
When debugging the pack protocol, it is sometimes useful to
store the verbatim pack that we sent or received on the
wire. Looking at the on-disk result is often not helpful for
a few reasons:

  1. If the operation is a clone, we destroy the repo on
     failure, leaving nothing on disk.

  2. If the pack is small, we unpack it immediately, and the
     full pack never hits the disk.

  3. If we feed the pack to "index-pack --fix-thin", the
     resulting pack has the extra delta bases added to it.

We already have a GIT_TRACE_PACKET mechanism for tracing
packets. Let's extend it with GIT_TRACE_PACKFILE to dump the
verbatim packfile.

There are a few other positive fallouts that come from
rearranging this code:

 - We currently disable the packet trace after seeing the
   PACK header, even though we may get human-readable lines
   on other sidebands; now we include them in the trace.

 - We currently try to print "PACK ..." in the trace to
   indicate that the packfile has started. But because we
   disable packet tracing, we never printed this line. We
   will now do so.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-06-16 13:24:22 -07:00

115 lines
3.6 KiB
C

#ifndef TRACE_H
#define TRACE_H
#include "git-compat-util.h"
#include "strbuf.h"
struct trace_key {
const char * const key;
int fd;
unsigned int initialized : 1;
unsigned int need_close : 1;
};
#define TRACE_KEY_INIT(name) { "GIT_TRACE_" #name, 0, 0, 0 }
extern void trace_repo_setup(const char *prefix);
extern int trace_want(struct trace_key *key);
extern void trace_disable(struct trace_key *key);
extern uint64_t getnanotime(void);
extern void trace_command_performance(const char **argv);
extern void trace_verbatim(struct trace_key *key, const void *buf, unsigned len);
#ifndef HAVE_VARIADIC_MACROS
__attribute__((format (printf, 1, 2)))
extern void trace_printf(const char *format, ...);
__attribute__((format (printf, 2, 3)))
extern void trace_printf_key(struct trace_key *key, const char *format, ...);
__attribute__((format (printf, 2, 3)))
extern void trace_argv_printf(const char **argv, const char *format, ...);
extern void trace_strbuf(struct trace_key *key, const struct strbuf *data);
/* Prints elapsed time (in nanoseconds) if GIT_TRACE_PERFORMANCE is enabled. */
__attribute__((format (printf, 2, 3)))
extern void trace_performance(uint64_t nanos, const char *format, ...);
/* Prints elapsed time since 'start' if GIT_TRACE_PERFORMANCE is enabled. */
__attribute__((format (printf, 2, 3)))
extern void trace_performance_since(uint64_t start, const char *format, ...);
#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)
#define trace_performance(nanos, ...) \
trace_performance_fl(TRACE_CONTEXT, __LINE__, nanos, __VA_ARGS__)
#define trace_performance_since(start, ...) \
trace_performance_fl(TRACE_CONTEXT, __LINE__, getnanotime() - (start), \
__VA_ARGS__)
/* 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);
__attribute__((format (printf, 4, 5)))
extern void trace_performance_fl(const char *file, int line,
uint64_t nanos, const char *fmt, ...);
#endif /* HAVE_VARIADIC_MACROS */
#endif /* TRACE_H */