path: root/lib/Support/Windows/Path.inc

//===- llvm/Support/Win32/Path.cpp - Win32 Path Implementation ---*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file provides the Win32 specific implementation of the Path class.
//
//===----------------------------------------------------------------------===//

//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only generic Win32 code that
//===          is guaranteed to work on *all* Win32 variants.
//===----------------------------------------------------------------------===//

#include "Windows.h"
#include <malloc.h>
#include <cstdio>

// We need to undo a macro defined in Windows.h, otherwise we won't compile:
#undef CopyFile
#undef GetCurrentDirectory

// Windows happily accepts either forward or backward slashes, though any path
// returned by a Win32 API will have backward slashes.  As LLVM code basically
// assumes forward slashes are used, backward slashs are converted where they
// can be introduced into a path.
//
// Another invariant is that a path ends with a slash if and only if the path
// is a root directory.  Any other use of a trailing slash is stripped.  Unlike
// in Unix, Windows has a rather complicated notion of a root path and this
// invariant helps simply the code.

static void FlipBackSlashes(std::string& s) {
  for (size_t i = 0; i < s.size(); i++)
    if (s[i] == '\\')
      s[i] = '/';
}

namespace llvm {
namespace sys {

const char PathSeparator = ';';

StringRef Path::GetEXESuffix() {
  return "exe";
}

Path::Path(llvm::StringRef p)
  : path(p) {
  FlipBackSlashes(path);
}

Path::Path(const char *StrStart, unsigned StrLen)
  : path(StrStart, StrLen) {
  FlipBackSlashes(path);
}

Path&
Path::operator=(StringRef that) {
  path.assign(that.data(), that.size());
  FlipBackSlashes(path);
  return *this;
}

// push_back 0 on create, and pop_back on delete.
struct ScopedNullTerminator {
  std::string &str;
  ScopedNullTerminator(std::string &s) : str(s) { str.push_back(0); }
  ~ScopedNullTerminator() {
    // str.pop_back(); But wait, C++03 doesn't have this...
    assert(!str.empty() && str[str.size() - 1] == 0
      && "Null char not present!");
    str.resize(str.size() - 1);
  }
};

bool
Path::isValid() const {
  if (path.empty())
    return false;

  // If there is a colon, it must be the second character, preceded by a letter
  // and followed by something.
  size_t len = path.size();
  // This code assumes that path is null terminated, so make sure it is.
  ScopedNullTerminator snt(path);
  size_t pos = path.rfind(':',len);
  size_t rootslash = 0;
  if (pos != std::string::npos) {
    if (pos != 1 || !isalpha(path[0]) || len < 3)
      return false;
      rootslash = 2;
  }

  // Look for a UNC path, and if found adjust our notion of the root slash.
  if (len > 3 && path[0] == '/' && path[1] == '/') {
    rootslash = path.find('/', 2);
    if (rootslash == std::string::npos)
      rootslash = 0;
  }

  // Check for illegal characters.
  if (path.find_first_of("\\<>\"|\001\002\003\004\005\006\007\010\011\012"
                         "\013\014\015\016\017\020\021\022\023\024\025\026"
                         "\027\030\031\032\033\034\035\036\037")
      != std::string::npos)
    return false;

  // Remove trailing slash, unless it's a root slash.
  if (len > rootslash+1 && path[len-1] == '/')
    path.erase(--len);

  // Check each component for legality.
  for (pos = 0; pos < len; ++pos) {
    // A component may not end in a space.
    if (path[pos] == ' ') {
      if (path[pos+1] == '/' || path[pos+1] == '\0')
        return false;
    }

    // A component may not end in a period.
    if (path[pos] == '.') {
      if (path[pos+1] == '/' || path[pos+1] == '\0') {
        // Unless it is the pseudo-directory "."...
        if (pos == 0 || path[pos-1] == '/' || path[pos-1] == ':')
          return true;
        // or "..".
        if (pos > 0 && path[pos-1] == '.') {