/* Test the __libc_readline_unlocked function.

   Copyright (C) 2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

/* Exercise __libc_readline_unlocked with various combinations of line

   lengths, stdio buffer sizes, and line read buffer sizes.  */

#include <errno.h>

#include <stdbool.h>

#include <stdio.h>

#include <string.h>

#include <support/check.h>

#include <support/support.h>

#include <support/temp_file.h>

#include <support/test-driver.h>

#include <support/xmemstream.h>

#include <support/xstdio.h>

#include <support/xunistd.h>

enum

  {

    maximum_line_length = 7,

    number_of_lines = 3,

  };

/* -1: Do not set buffer size.  0: unbuffered.  Otherwise, use this as

   the size of the buffer.  */

static int buffer_size;

/* These size of the buffer used for reading.  Must be at least 2.  */

static int read_size;

/* If a read files with ERANGE, increase the buffer size by this

   amount.  Must be positive.  */

static int read_size_increment;

/* If non-zero, do not reset the read size after an ERANGE error.  */

static int read_size_preserve;

/* If non-zero, no '\n' at the end of the file.  */

static int no_newline_at_eof;

/* Length of the line, or -1 if the line is not present.  */

static int line_lengths[number_of_lines];

/* The name of the test file.  */

static char *test_file_path;

/* The contents of the test file.  */

static char expected_contents[(maximum_line_length + 2) * number_of_lines + 1];

static size_t expected_length;

/* Returns a random byte which is not zero or the line terminator.  */

static char

random_char (void)

{

  static unsigned int rand_state = 1;

  while (true)

    {

      char result = rand_r (&rand_state) >> 16;

      if (result != 0 && result != '\n')

        return result;

    }

}

/* Create the test file.  */

static void

prepare (int argc, char **argv)

{

  int fd = create_temp_file ("tst-readline-", &test_file_path);

  TEST_VERIFY_EXIT (fd >= 0);

  xclose (fd);

}

/* Prepare the test file.  Return false if the test parameters are

   incongruent and the test should be skipped.  */

static bool

write_test_file (void)

{

  expected_length = 0;

  char *p = expected_contents;

  for (int lineno = 0; lineno < number_of_lines; ++lineno)

    for (int i = 0; i < line_lengths[lineno]; ++i)

      *p++ = random_char ();

  expected_length = p - &expected_contents[0];

  if (no_newline_at_eof)

    {

      if (expected_length == 0)

        return false;

      --expected_length;

      --p;

    }

  if (test_verbose > 0)

    {

      printf ("info: writing test file of %zu bytes:\n", expected_length);

      for (int i = 0; i < number_of_lines; ++i)

        printf (" line %d: %d\n", i, line_lengths[i]);

      if (no_newline_at_eof)

        puts ("  (no newline at EOF)");

    }

  TEST_VERIFY_EXIT (expected_length < sizeof (expected_contents));

  *p++ = '\0';

  support_write_file_string (test_file_path, expected_contents);

  return true;

}

/* Run a single test (a combination of a test file and read

   parameters).  */

static void

run_test (void)

{

  TEST_VERIFY_EXIT (read_size_increment > 0);

  if (test_verbose > 0)

    {

      printf ("info: running test: buffer_size=%d read_size=%d\n"

              "  read_size_increment=%d read_size_preserve=%d\n",

              buffer_size, read_size, read_size_increment, read_size_preserve);

    }

  struct xmemstream result;

  xopen_memstream (&result);

  FILE *fp = xfopen (test_file_path, "rce");

  char *fp_buffer = NULL;

  if (buffer_size == 0)

    TEST_VERIFY_EXIT (setvbuf (fp, NULL, _IONBF, 0) == 0);

  if (buffer_size > 0)

    {

      fp_buffer = xmalloc (buffer_size);

      TEST_VERIFY_EXIT (setvbuf (fp, fp_buffer, _IOFBF, buffer_size) == 0);

    }

  char *line_buffer = xmalloc (read_size);

  size_t line_buffer_size = read_size;

  while (true)

    {

      ssize_t ret = __libc_readline_unlocked

        (fp, line_buffer, line_buffer_size);

      if (ret < 0)

        {

          TEST_VERIFY (ret == -1);

          if (errno != ERANGE)

            FAIL_EXIT1 ("__libc_readline_unlocked: %m");

          line_buffer_size += read_size_increment;

          free (line_buffer);

          line_buffer = xmalloc (line_buffer_size);

          /* Try reading this line again.  */

        }

      else if (ret == 0)

        break;

      else

        {

          /* A line has been read.  Save it.  */

          TEST_VERIFY (ret == strlen (line_buffer));

          const char *pnl = strchr (line_buffer, '\n');

          /* If there is a \n, it must be at the end.  */

          TEST_VERIFY (pnl == NULL || pnl == line_buffer + ret - 1);

          fputs (line_buffer, result.out);

          /* Restore the original read size if required.  */

          if (line_buffer_size > read_size && !read_size_preserve)

            {

              line_buffer_size = read_size;

              free (line_buffer);

              line_buffer = xmalloc (line_buffer_size);

            }

        }

    }

  xfclose (fp);

  free (fp_buffer);

  free (line_buffer);

  xfclose_memstream (&result);

  TEST_VERIFY (result.length == expected_length);

  TEST_VERIFY (strcmp (result.buffer, expected_contents) == 0);

  if (test_verbose > 0)

    {

      printf ("info: expected (%zu): [[%s]]\n",

              expected_length, expected_contents);

      printf ("info:   actual (%zu): [[%s]]\n", result.length, result.buffer);

    }

  free (result.buffer);

}

/* Test one test file with multiple read parameters.  */

static void

test_one_file (void)

{

  for (buffer_size = -1; buffer_size <= maximum_line_length + 1; ++buffer_size)

    for (read_size = 2; read_size <= maximum_line_length + 2; ++read_size)

      for (read_size_increment = 1; read_size_increment <= 4;

           ++read_size_increment)

        for (read_size_preserve = 0; read_size_preserve < 2;

             ++read_size_preserve)

          run_test ();

}

static int

do_test (void)

{

  /* Set up the test file contents.  */

  for (line_lengths[0] = -1; line_lengths[0] <= maximum_line_length;

       ++line_lengths[0])

    for (line_lengths[1] = -1; line_lengths[1] <= maximum_line_length;

         ++line_lengths[1])

      for (line_lengths[2] = -1; line_lengths[2] <= maximum_line_length;

           ++line_lengths[2])

        for (no_newline_at_eof = 0; no_newline_at_eof < 2; ++no_newline_at_eof)

          {

            if (!write_test_file ())

              continue;

            test_one_file ();

          }

  free (test_file_path);

  return 0;

}

#define PREPARE prepare

#include <support/test-driver.c>