/*

 * GIT - The information manager from hell

 *

 * Copyright (C) 2000-2002 Michael R. Elkins <me@mutt.org>

 * Copyright (C) 2002-2004 Oswald Buddenhagen <ossi@users.sf.net>

 * Copyright (C) 2004 Theodore Y. Ts'o <tytso@mit.edu>

 * Copyright (C) 2006 Mike McCormack

 * Copyright (C) 2006 Christian Couder

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; either version 2 of the License, or

 *  (at your option) any later version.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, see <https://www.gnu.org/licenses/>.

 */

#include "git-compat-util.h"

#include "abspath.h"

#include "environment.h"

#include "quote.h"

#include "setup.h"

#include "trace.h"

struct trace_key trace_default_key = { "GIT_TRACE", 0, 0, 0 };

struct trace_key trace_perf_key = TRACE_KEY_INIT(PERFORMANCE);

struct trace_key trace_setup_key = TRACE_KEY_INIT(SETUP);

/* Get a trace file descriptor from "key" env variable. */

static int get_trace_fd(struct trace_key *key, const char *override_envvar)

{

  const char *trace;

  /* don't open twice */

  if (key->initialized)

    return key->fd;

  trace = override_envvar ? override_envvar : getenv(key->key);

  if (!trace || !strcmp(trace, "") ||

      !strcmp(trace, "0") || !strcasecmp(trace, "false"))

    key->fd = 0;

  else if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))

    key->fd = STDERR_FILENO;

  else if (strlen(trace) == 1 && isdigit(*trace))

    key->fd = atoi(trace);

  else if (is_absolute_path(trace)) {

    int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);

    if (fd == -1) {

      warning("could not open '%s' for tracing: %s",

        trace, strerror(errno));

      trace_disable(key);

    } else {

      key->fd = fd;

      key->need_close = 1;

    }

  } else {

    warning("unknown trace value for '%s': %s\n"

      "         If you want to trace into a file, then please set %s\n"

      "         to an absolute pathname (starting with /)",

      key->key, trace, key->key);

    trace_disable(key);

  }

  key->initialized = 1;

  return key->fd;

}

void trace_override_envvar(struct trace_key *key, const char *value)

{

  trace_disable(key);

  key->initialized = 0;

  /*

   * Invoke get_trace_fd() to initialize key using the given value

   * instead of the value of the environment variable.

   */

  get_trace_fd(key, value);

}

void trace_disable(struct trace_key *key)

{

  if (key->need_close)

    close(key->fd);

  key->fd = 0;

  key->initialized = 1;

  key->need_close = 0;

}

static int prepare_trace_line(const char *file, int line,

            struct trace_key *key, struct strbuf *buf)

{

  static struct trace_key trace_bare = TRACE_KEY_INIT(BARE);

  struct timeval tv;

  struct tm tm;

  time_t secs;

  if (!trace_want(key))

    return 0;

  /* unit tests may want to disable additional trace output */

  if (trace_want(&trace_bare))

    return 1;

  /* print current timestamp */

  gettimeofday(&tv, NULL);

  secs = tv.tv_sec;

  localtime_r(&secs, &tm);

  strbuf_addf(buf, "%02d:%02d:%02d.%06ld %s:%d", tm.tm_hour, tm.tm_min,

        tm.tm_sec, (long) tv.tv_usec, file, line);

  /* align trace output (column 40 catches most files names in git) */

  while (buf->len < 40)

    strbuf_addch(buf, ' ');

  return 1;

}

static void trace_write(struct trace_key *key, const void *buf, unsigned len)

{

  if (write_in_full(get_trace_fd(key, NULL), buf, len) < 0) {

    warning("unable to write trace for %s: %s",

      key->key, strerror(errno));

    trace_disable(key);

  }

}

void trace_verbatim(struct trace_key *key, const void *buf, unsigned len)

{

  if (!trace_want(key))

    return;

  trace_write(key, buf, len);

}

static void print_trace_line(struct trace_key *key, struct strbuf *buf)

{

  strbuf_complete_line(buf);

  trace_write(key, buf->buf, buf->len);

}

static void trace_vprintf_fl(const char *file, int line, struct trace_key *key,

           const char *format, va_list ap)

{

  struct strbuf buf = STRBUF_INIT;

  if (!prepare_trace_line(file, line, key, &buf))

    return;

  strbuf_vaddf(&buf, format, ap);

  print_trace_line(key, &buf);

  strbuf_release(&buf);

}

static void trace_argv_vprintf_fl(const char *file, int line,

          const char **argv, const char *format,

          va_list ap)

{

  struct strbuf buf = STRBUF_INIT;

  if (!prepare_trace_line(file, line, &trace_default_key, &buf))

    return;

  strbuf_vaddf(&buf, format, ap);

  sq_quote_argv_pretty(&buf, argv);

  print_trace_line(&trace_default_key, &buf);

  strbuf_release(&buf);

}

void trace_strbuf_fl(const char *file, int line, struct trace_key *key,

         const struct strbuf *data)

{

  struct strbuf buf = STRBUF_INIT;

  if (!prepare_trace_line(file, line, key, &buf))

    return;

  strbuf_addbuf(&buf, data);

  print_trace_line(key, &buf);

  strbuf_release(&buf);

}

static uint64_t perf_start_times[10];

static int perf_indent;

uint64_t trace_performance_enter(void)

{

  uint64_t now;

  if (!trace_want(&trace_perf_key))

    return 0;

  now = getnanotime();

  perf_start_times[perf_indent] = now;

  if (perf_indent + 1 < ARRAY_SIZE(perf_start_times))

    perf_indent++;

  else

    BUG("Too deep indentation");

  return now;

}

static void trace_performance_vprintf_fl(const char *file, int line,

           uint64_t nanos, const char *format,

           va_list ap)

{

  static const char space[] = "          ";

  struct strbuf buf = STRBUF_INIT;

  if (!prepare_trace_line(file, line, &trace_perf_key, &buf))

    return;

  strbuf_addf(&buf, "performance: %.9f s", (double) nanos / 1000000000);

  if (format && *format) {

    if (perf_indent >= strlen(space))

      BUG("Too deep indentation");

    strbuf_addf(&buf, ":%.*s ", perf_indent, space);

    strbuf_vaddf(&buf, format, ap);

  }

  print_trace_line(&trace_perf_key, &buf);

  strbuf_release(&buf);

}

void trace_printf_key_fl(const char *file, int line, struct trace_key *key,

       const char *format, ...)

{

  va_list ap;

  va_start(ap, format);

  trace_vprintf_fl(file, line, key, format, ap);

  va_end(ap);

}

void trace_argv_printf_fl(const char *file, int line, const char **argv,

        const char *format, ...)

{

  va_list ap;

  va_start(ap, format);

  trace_argv_vprintf_fl(file, line, argv, format, ap);

  va_end(ap);

}

void trace_performance_fl(const char *file, int line, uint64_t nanos,

            const char *format, ...)

{

  va_list ap;

  va_start(ap, format);

  trace_performance_vprintf_fl(file, line, nanos, format, ap);

  va_end(ap);

}

void trace_performance_leave_fl(const char *file, int line,

        uint64_t nanos, const char *format, ...)

{

  va_list ap;

  uint64_t since;

  if (perf_indent)

    perf_indent--;

  if (!format) /* Allow callers to leave without tracing anything */

    return;

  since = perf_start_times[perf_indent];

  va_start(ap, format);

  trace_performance_vprintf_fl(file, line, nanos - since, format, ap);

  va_end(ap);

}

static const char *quote_crnl(const char *path)

{

  static struct strbuf new_path = STRBUF_INIT;

  if (!path)

    return NULL;

  strbuf_reset(&new_path);

  while (*path) {

    switch (*path) {

    case '\\': strbuf_addstr(&new_path, "\\\\"); break;

    case '\n': strbuf_addstr(&new_path, "\\n"); break;

    case '\r': strbuf_addstr(&new_path, "\\r"); break;

    default:

      strbuf_addch(&new_path, *path);

    }

    path++;

  }

  return new_path.buf;

}

void trace_repo_setup(void)

{

  const char *git_work_tree, *prefix = startup_info->prefix;

  char *cwd;

  if (!trace_want(&trace_setup_key))

    return;

  cwd = xgetcwd();

  if (!(git_work_tree = get_git_work_tree()))

    git_work_tree = "(null)";

  if (!startup_info->prefix)

    prefix = "(null)";

  trace_printf_key(&trace_setup_key, "setup: git_dir: %s\n", quote_crnl(get_git_dir()));

  trace_printf_key(&trace_setup_key, "setup: git_common_dir: %s\n", quote_crnl(get_git_common_dir()));

  trace_printf_key(&trace_setup_key, "setup: worktree: %s\n", quote_crnl(git_work_tree));

  trace_printf_key(&trace_setup_key, "setup: cwd: %s\n", quote_crnl(cwd));

  trace_printf_key(&trace_setup_key, "setup: prefix: %s\n", quote_crnl(prefix));

  free(cwd);

}

int trace_want(struct trace_key *key)

{

  return !!get_trace_fd(key, NULL);

}

#if defined(HAVE_CLOCK_GETTIME) && defined(HAVE_CLOCK_MONOTONIC)

static inline uint64_t highres_nanos(void)

{

  struct timespec ts;

  if (clock_gettime(CLOCK_MONOTONIC, &ts))

    return 0;

  return (uint64_t) ts.tv_sec * 1000000000 + ts.tv_nsec;

}

#elif defined (GIT_WINDOWS_NATIVE)

static inline uint64_t highres_nanos(void)

{

  static uint64_t high_ns, scaled_low_ns;

  static int scale;

  LARGE_INTEGER cnt;

  if (!scale) {

    if (!QueryPerformanceFrequency(&cnt))

      return 0;

    /* high_ns = number of ns per cnt.HighPart */

    high_ns = (1000000000LL << 32) / (uint64_t) cnt.QuadPart;

    /*

     * Number of ns per cnt.LowPart is 10^9 / frequency (or

     * high_ns >> 32). For maximum precision, we scale this factor

     * so that it just fits within 32 bit (i.e. won't overflow if

     * multiplied with cnt.LowPart).

     */

    scaled_low_ns = high_ns;

    scale = 32;

    while (scaled_low_ns >= 0x100000000LL) {

      scaled_low_ns >>= 1;

      scale--;

    }

  }

  /* if QPF worked on initialization, we expect QPC to work as well */

  QueryPerformanceCounter(&cnt);

  return (high_ns * cnt.HighPart) +

         ((scaled_low_ns * cnt.LowPart) >> scale);

}

#else

# define highres_nanos() 0

#endif

static inline uint64_t gettimeofday_nanos(void)

{

  struct timeval tv;

  gettimeofday(&tv, NULL);

  return (uint64_t) tv.tv_sec * 1000000000 + tv.tv_usec * 1000;

}

/*

 * Returns nanoseconds since the epoch (01/01/1970), for performance tracing

 * (i.e. favoring high precision over wall clock time accuracy).

 */

uint64_t getnanotime(void)

{

  static uint64_t offset;

  if (offset > 1) {

    /* initialization succeeded, return offset + high res time */

    return offset + highres_nanos();

  } else if (offset == 1) {

    /* initialization failed, fall back to gettimeofday */

    return gettimeofday_nanos();

  } else {

    /* initialize offset if high resolution timer works */

    uint64_t now = gettimeofday_nanos();

    uint64_t highres = highres_nanos();

    if (highres)

      offset = now - highres;

    else

      offset = 1;

    return now;

  }

}

static struct strbuf command_line = STRBUF_INIT;

static void print_command_performance_atexit(void)

{

  trace_performance_leave("git command:%s", command_line.buf);

}

void trace_command_performance(const char **argv)

{

  if (!trace_want(&trace_perf_key))

    return;

  if (!command_line.len)

    atexit(print_command_performance_atexit);

  strbuf_reset(&command_line);

  sq_quote_argv_pretty(&command_line, argv);

  trace_performance_enter();

}