From c69dfd24db21be54ec5a17bb3e07c81f4e96861a Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Sat, 12 Jul 2014 02:02:18 +0200 Subject: trace: add infrastructure to augment trace output with additional info To be able to add a common prefix or suffix to all trace output (e.g. a timestamp or file:line of the caller), factor out common setup and cleanup tasks of the trace* functions. When adding a common prefix, it makes sense that the output of each trace call starts on a new line. Add '\n' in case the caller forgot. Note that this explicitly limits trace output to line-by-line, it is no longer possible to trace-print just part of a line. Until now, this was just an implicit assumption (trace-printing part of a line worked, but messed up the trace file if multiple threads or processes were involved). Thread-safety / inter-process-safety is also the reason why we need to do the prefixing and suffixing in memory rather than issuing multiple write() calls. Write_or_whine_pipe() / xwrite() is atomic unless the size exceeds MAX_IO_SIZE (8MB, see wrapper.c). In case of trace_strbuf, this costs an additional string copy (which should be irrelevant for performance in light of actual file IO). While we're at it, rename trace_strbuf's 'buf' argument, which suggests that the function is modifying the buffer. Trace_strbuf() currently is the only trace API that can print arbitrary binary data (without barfing on '%' or stopping at '\0'), so 'data' seems more appropriate. Signed-off-by: Karsten Blees Signed-off-by: Junio C Hamano --- trace.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'trace.h') diff --git a/trace.h b/trace.h index d85ac4c65..28c10892d 100644 --- a/trace.h +++ b/trace.h @@ -22,6 +22,6 @@ extern int trace_want(struct trace_key *key); extern void trace_disable(struct trace_key *key); __attribute__((format (printf, 2, 3))) extern void trace_printf_key(struct trace_key *key, const char *format, ...); -extern void trace_strbuf(struct trace_key *key, const struct strbuf *buf); +extern void trace_strbuf(struct trace_key *key, const struct strbuf *data); #endif /* TRACE_H */ -- cgit v1.2.1