// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

#include "platform/globals.h"
#if defined(HOST_OS_MACOS)

#include "platform/utils.h"

#include <errno.h>        // NOLINT
#include <sys/utsname.h>  // NOLINT

namespace dart {

char* Utils::StrNDup(const char* s, intptr_t n) {
// strndup has only been added to Mac OS X in 10.7. We are supplying
// our own copy here if needed.
#if !defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) ||                 \
    __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ <= 1060
  intptr_t len = strlen(s);
  if ((n < 0) || (len < 0)) {
    return NULL;
  }
  if (n < len) {
    len = n;
  }
  char* result = reinterpret_cast<char*>(malloc(len + 1));
  if (result == NULL) {
    return NULL;
  }
  result[len] = '\0';
  return reinterpret_cast<char*>(memmove(result, s, len));
#else   // !defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) || ...
  return strndup(s, n);
#endif  // !defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) || ...
}

intptr_t Utils::StrNLen(const char* s, intptr_t n) {
// strnlen has only been added to Mac OS X in 10.7. We are supplying
// our own copy here if needed.
#if !defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) ||                 \
    __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ <= 1060
  intptr_t len = 0;
  while ((len <= n) && (*s != '\0')) {
    s++;
    len++;
  }
  return len;
#else   // !defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) || ...
  return strnlen(s, n);
#endif  // !defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) || ...
}

int Utils::SNPrint(char* str, size_t size, const char* format, ...) {
  va_list args;
  va_start(args, format);
  int retval = VSNPrint(str, size, format, args);
  va_end(args);
  return retval;
}

int Utils::VSNPrint(char* str, size_t size, const char* format, va_list args) {
  int retval = vsnprintf(str, size, format, args);
  if (retval < 0) {
    FATAL1("Fatal error in Utils::VSNPrint with format '%s'", format);
  }
  return retval;
}

namespace internal {

// Returns the running system's Darwin major version. Don't call this, it's
// an implementation detail and its result is meant to be cached by
// MacOSXMinorVersion.
int32_t DarwinMajorVersionInternal() {
  // uname is implemented as a simple series of sysctl system calls to
  // obtain the relevant data from the kernel. The data is
  // compiled right into the kernel, so no threads or blocking or other
  // funny business is necessary.

  struct utsname uname_info;
  if (uname(&uname_info) != 0) {
    FATAL("Fatal error in DarwinMajorVersionInternal : invalid return uname");
    return 0;
  }

  if (strcmp(uname_info.sysname, "Darwin") != 0) {
    FATAL1(
        "Fatal error in DarwinMajorVersionInternal : unexpected uname"
        " sysname '%s'",
        uname_info.sysname);
    return 0;
  }

  int32_t darwin_major_version = 0;
  char* dot = strchr(uname_info.release, '.');
  if (dot) {
    errno = 0;
    char* end_ptr = NULL;
    darwin_major_version = strtol(uname_info.release, &end_ptr, 10);
    if (errno != 0 || (end_ptr == uname_info.release)) {
      dot = NULL;
    }
  }

  if (!dot) {
    FATAL1(
        "Fatal error in DarwinMajorVersionInternal :"
        " could not parse uname release '%s'",
        uname_info.release);
    return 0;
  }

  return darwin_major_version;
}

// Returns the running system's Mac OS X minor version. This is the |y| value
// in 10.y or 10.y.z. Don't call this, it's an implementation detail and the
// result is meant to be cached by MacOSXMinorVersion.
int32_t MacOSXMinorVersionInternal() {
  int darwin_major_version = DarwinMajorVersionInternal();

  // The Darwin major version is always 4 greater than the Mac OS X minor
  // version for Darwin versions beginning with 6, corresponding to Mac OS X
  // 10.2. Since this correspondence may change in the future, warn when
  // encountering a version higher than anything seen before. Older Darwin
  // versions, or versions that can't be determined, result in
  // immediate death.
  ASSERT(darwin_major_version >= 6);
  return (darwin_major_version - 4);
}

int32_t MacOSXMinorVersion() {
  static int mac_os_x_minor_version = MacOSXMinorVersionInternal();
  return mac_os_x_minor_version;
}

}  // namespace internal

}  // namespace dart

#endif  // defined(HOST_OS_MACOS)