cpp

// libc.cc: Replacement for pyext/libc.c

#include "cpp/libc.h"

#include <errno.h>

#include <fnmatch.h>

#include <glob.h>

#include <locale.h>

#include <regex.h>

#include <sys/ioctl.h>

#include <unistd.h>  // gethostname()

#include <wchar.h>

namespace libc {

Str* gethostname() {

  Str* result = OverAllocatedStr(HOST_NAME_MAX);

  int status = ::gethostname(result->data_, HOST_NAME_MAX);

  if (status != 0) {

    throw Alloc<OSError>(errno);

  }

  // Important: set the length of the string!

  result->MaybeShrink(strlen(result->data_));

  return result;

}

Str* realpath(Str* path) {

  Str* result = OverAllocatedStr(PATH_MAX);

  char* p = ::realpath(path->data_, result->data_);

  if (p == nullptr) {

    throw Alloc<OSError>(errno);

  }

  result->MaybeShrink(strlen(result->data_));

  return result;

}

int fnmatch(Str* pat, Str* str) {

  int flags = FNM_EXTMATCH;

  int result = ::fnmatch(pat->data_, str->data_, flags);

  switch (result) {

  case 0:

    return 1;

  case FNM_NOMATCH:

    return 0;

  default:

    // Other error

    return -1;

  }

}

List<Str*>* glob(Str* pat) {

  glob_t results;

  // Hm, it's weird that the first one can't be called with GLOB_APPEND.  You

  // get a segfault.

  int flags = 0;

  // int flags = GLOB_APPEND;

  // flags |= GLOB_NOMAGIC;

  int ret = glob(pat->data_, flags, NULL, &results);

  const char* err_str = NULL;

  switch (ret) {

  case 0:  // no error

    break;

  case GLOB_ABORTED:

    err_str = "read error";

    break;

  case GLOB_NOMATCH:

    // No error, because not matching isn't necessarily a problem.

    // NOTE: This can be turned on to log overaggressive calls to glob().

    // err_str = "nothing matched";

    break;

  case GLOB_NOSPACE:

    err_str = "no dynamic memory";

    break;

  default:

    err_str = "unknown problem";

    break;

  }

  if (err_str) {

    throw Alloc<RuntimeError>(StrFromC(err_str));

  }

  // http://stackoverflow.com/questions/3512414/does-this-pylist-appendlist-py-buildvalue-leak

  size_t n = results.gl_pathc;

  auto matches = NewList<Str*>();

  // Print array of results

  size_t i;

  for (i = 0; i < n; i++) {

    const char* m = results.gl_pathv[i];

    matches->append(StrFromC(m));

  }

  globfree(&results);

  return matches;

}

// Raises RuntimeError if the pattern is invalid.  TODO: Use a different

// exception?

List<Str*>* regex_match(Str* pattern, Str* str) {

  List<Str*>* results = NewList<Str*>();

  regex_t pat;

  if (regcomp(&pat, pattern->data_, REG_EXTENDED) != 0) {

    // TODO: check error code, as in func_regex_parse()

    throw Alloc<RuntimeError>(StrFromC("Invalid regex syntax (regex_match)"));

  }

  int outlen = pat.re_nsub + 1;  // number of captures

  const char* s0 = str->data_;

  regmatch_t* pmatch =

      static_cast<regmatch_t*>(malloc(sizeof(regmatch_t) * outlen));

  int match = regexec(&pat, s0, outlen, pmatch, 0) == 0;

  if (match) {

    int i;

    for (i = 0; i < outlen; i++) {

      int len = pmatch[i].rm_eo - pmatch[i].rm_so;

      Str* m = StrFromC(s0 + pmatch[i].rm_so, len);

      results->append(m);

    }

  }

  free(pmatch);

  regfree(&pat);

  if (!match) {

    return nullptr;

  }

  return results;

}

// For ${//}, the number of groups is always 1, so we want 2 match position

// results -- the whole regex (which we ignore), and then first group.

//

// For [[ =~ ]], do we need to count how many matches the user gave?

const int NMATCH = 2;

// Odd: This a Tuple2* not Tuple2 because it's Optional[Tuple2]!

Tuple2<int, int>* regex_first_group_match(Str* pattern, Str* str, int pos) {

  regex_t pat;

  regmatch_t m[NMATCH];

  // Could have been checked by regex_parse for [[ =~ ]], but not for glob

  // patterns like ${foo/x*/y}.

  if (regcomp(&pat, pattern->data_, REG_EXTENDED) != 0) {

    throw Alloc<RuntimeError>(

        StrFromC("Invalid regex syntax (func_regex_first_group_match)"));

  }

  // Match at offset 'pos'

  int result = regexec(&pat, str->data_ + pos, NMATCH, m, 0 /*flags*/);

  regfree(&pat);

  if (result != 0) {

    return nullptr;

  }

  // Assume there is a match

  regoff_t start = m[1].rm_so;

  regoff_t end = m[1].rm_eo;

  Tuple2<int, int>* tup = Alloc<Tuple2<int, int>>(pos + start, pos + end);

  return tup;

}

// TODO: SHARE with pyext

int wcswidth(Str* s) {

  // Behavior of mbstowcs() depends on LC_CTYPE

  // Calculate length first

  int num_wide_chars = mbstowcs(NULL, s->data_, 0);

  if (num_wide_chars == -1) {

    throw Alloc<UnicodeError>(StrFromC("mbstowcs() 1"));

  }

  // Allocate buffer

  int buf_size = (num_wide_chars + 1) * sizeof(wchar_t);

  wchar_t* wide_chars = static_cast<wchar_t*>(malloc(buf_size));

  assert(wide_chars != nullptr);

  // Convert to wide chars

  num_wide_chars = mbstowcs(wide_chars, s->data_, num_wide_chars);

  if (num_wide_chars == -1) {

    throw Alloc<UnicodeError>(StrFromC("mbstowcs() 2"));

  }

  // Find number of columns

  int width = ::wcswidth(wide_chars, num_wide_chars);

  if (width == -1) {

    // unprintable chars

    throw Alloc<UnicodeError>(StrFromC("wcswidth()"));

  }

  free(wide_chars);

  return width;

}

int get_terminal_width() {

  struct winsize w;

  if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &w) == -1) {

    throw Alloc<IOError>(errno);

  }

  return w.ws_col;

}

}  // namespace libc