[Tarantool-patches] [PATCH luajit v2] memprof: add profile common section

[Maxim Kokryashkin]

A Lua API for sysprof needs to be introduced, but sysprof's C API is
quite similar with memprof's. Considering this, there are some
structures and functions that should be common among memprof's and
sysprof's implementations of Lua API to avoid duplication.

Part of tarantool/tarantool#781
---
GitHub branch: https://github.com/tarantool/luajit/tree/shishqa/gh-781-platform-and-lua-profiler

 src/lib_misc.c | 36 +++++++++++++++++++-----------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/src/lib_misc.c b/src/lib_misc.c
index 1dab08cc..22d29d78 100644
--- a/src/lib_misc.c
+++ b/src/lib_misc.c
@@ -8,8 +8,9 @@
 #define lib_misc_c
 #define LUA_LIB
 
-#include <stdio.h>
 #include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
 
 #include "lua.h"
 #include "lmisclib.h"
@@ -75,9 +76,7 @@ LJLIB_CF(misc_getmetrics)
 
 #include "lj_libdef.h"
 
-/* ----- misc.memprof module ---------------------------------------------- */
-
-#define LJLIB_MODULE_misc_memprof
+/* --------- profile common section --------------------------------------- */
 
 /*
 ** Yep, 8Mb. Tuned in order not to bother the platform with too often flushes.
@@ -85,9 +84,9 @@ LJLIB_CF(misc_getmetrics)
 #define STREAM_BUFFER_SIZE (8 * 1024 * 1024)
 
 /* Structure given as ctx to memprof writer and on_stop callback. */
-struct memprof_ctx {
-  /* Output file stream for data. */
-  FILE *stream;
+struct profile_ctx {
+  /* Output file descriptor for data. */
+  int fd;
   /* Profiled global_State for lj_mem_free at on_stop callback. */
   global_State *g;
   /* Buffer for data. */
@@ -96,13 +95,13 @@ struct memprof_ctx {
 
 /*
 ** Default buffer writer function.
-** Just call fwrite to the corresponding FILE.
+** Just call write to the corresponding descriptor.
 */
 static size_t buffer_writer_default(const void **buf_addr, size_t len,
 				    void *opt)
 {
-  struct memprof_ctx *ctx = opt;
-  FILE *stream = ctx->stream;
+  struct profile_ctx *ctx = opt;
+  const int fd = ctx->fd;
   const void * const buf_start = *buf_addr;
   const void *data = *buf_addr;
   size_t write_total = 0;
@@ -110,9 +109,9 @@ static size_t buffer_writer_default(const void **buf_addr, size_t len,
   lua_assert(len <= STREAM_BUFFER_SIZE);
 
   for (;;) {
-    const size_t written = fwrite(data, 1, len - write_total, stream);
+    const size_t written = write(fd, data, len - write_total);
 
-    if (LJ_UNLIKELY(written == 0)) {
+    if (LJ_UNLIKELY(written == -1)) {
       /* Re-tries write in case of EINTR. */
       if (errno != EINTR) {
 	/* Will be freed as whole chunk later. */
@@ -137,22 +136,25 @@ static size_t buffer_writer_default(const void **buf_addr, size_t len,
   return write_total;
 }
 
-/* Default on stop callback. Just close the corresponding stream. */
+/* Default on stop callback. Just close the corresponding descriptor. */
 static int on_stop_cb_default(void *opt, uint8_t *buf)
 {
-  struct memprof_ctx *ctx = opt;
-  FILE *stream = ctx->stream;
+  struct profile_ctx *ctx = opt;
+  const int fd = ctx->fd;
   UNUSED(buf);
   lj_mem_free(ctx->g, ctx, sizeof(*ctx));
-  return fclose(stream);
+  return close(fd);
 }
 
+/* ----- misc.memprof module ---------------------------------------------- */
+
+#define LJLIB_MODULE_misc_memprof
 /* local started, err, errno = misc.memprof.start(fname) */
 LJLIB_CF(misc_memprof_start)
 {
   struct lj_memprof_options opt = {0};
   const char *fname = strdata(lj_lib_checkstr(L, 1));
-  struct memprof_ctx *ctx;
+  struct profile_ctx *ctx;
   int memprof_status;
 
   /*
-- 
2.33.0