path: root/lib/Support/PathV2.cpp

//===-- PathV2.cpp - Implement OS Path Concept ------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements the operating system PathV2 API.
//
//===----------------------------------------------------------------------===//

#include "llvm/Support/PathV2.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FileSystem.h"
#include <cctype>
#include <cstdio>
#include <cstring>

namespace {
  using llvm::StringRef;
  using llvm::sys::path::is_separator;

#ifdef LLVM_ON_WIN32
  const char *separators = "\\/";
  const char  prefered_separator = '\\';
#else
  const char  separators = '/';
  const char  prefered_separator = '/';
#endif

  StringRef find_first_component(StringRef path) {
    // Look for this first component in the following order.
    // * empty (in this case we return an empty string)
    // * either C: or {//,\\}net.
    // * {/,\}
    // * {.,..}
    // * {file,directory}name

    if (path.empty())
      return path;

#ifdef LLVM_ON_WIN32
    // C:
    if (path.size() >= 2 && std::isalpha(path[0]) && path[1] == ':')
      return path.substr(0, 2);
#endif

    // //net
    if ((path.size() > 2) &&
        is_separator(path[0]) &&
        path[0] == path[1] &&
        !is_separator(path[2])) {
      // Find the next directory separator.
      size_t end = path.find_first_of(separators, 2);
      return path.substr(0, end);
    }

    // {/,\}
    if (is_separator(path[0]))
      return path.substr(0, 1);

    if (path.startswith(".."))
      return path.substr(0, 2);

    if (path[0] == '.')
      return path.substr(0, 1);

    // * {file,directory}name
    size_t end = path.find_first_of(separators, 2);
    return path.substr(0, end);
  }

  size_t filename_pos(StringRef str) {
    if (str.size() == 2 &&
        is_separator(str[0]) &&
        str[0] == str[1])
      return 0;

    if (str.size() > 0 && is_separator(str[str.size() - 1]))
      return str.size() - 1;

    size_t pos = str.find_last_of(separators, str.size() - 1);

#ifdef LLVM_ON_WIN32
    if (pos == StringRef::npos)
      pos = str.find_last_of(':', str.size() - 2);
#endif

    if (pos == StringRef::npos ||
        (pos == 1 && is_separator(str[0])))
      return 0;

    return pos + 1;
  }

  size_t root_dir_start(StringRef str) {
    // case "c:/"
#ifdef LLVM_ON_WIN32
    if (str.size() > 2 &&
        str[1] == ':' &&
        is_separator(str[2]))
      return 2;
#endif

    // case "//"
    if (str.size() == 2 &&
        is_separator(str[0]) &&
        str[0] == str[1])
      return StringRef::npos;

    // case "//net"
    if (str.size() > 3 &&
        is_separator(str[0]) &&
        str[0] == str[1] &&
        !is_separator(str[2])) {
      return str.find_first_of(separators, 2);
    }

    // case "/"
    if (str.size() > 0 && is_separator(str[0]))
      return 0;

    return StringRef::npos;
  }

  size_t parent_path_end(StringRef path) {
    size_t end_pos = filename_pos(path);

    bool filename_was_sep = path.size() > 0 && is_separator(path[end_pos]);

    // Skip separators except for root dir.
    size_t root_dir_pos = root_dir_start(path.substr(0, end_pos));

    while(end_pos > 0 &&
          (end_pos - 1) != root_dir_pos &&
          is_separator(path[end_pos - 1]))
      --end_pos;

    if (end_pos == 1 && root_dir_pos == 0 &&<