disk_interface.cc

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// Copyright 2011 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "disk_interface.h"

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>

#include "util.h"

namespace {

std::string DirName(const std::string& path) {
#ifdef WIN32
  const char kPathSeparator = '\\';
#else
  const char kPathSeparator = '/';
#endif

  std::string::size_type slash_pos = path.rfind(kPathSeparator);
  if (slash_pos == std::string::npos)
    return std::string();  // Nothing to do.
  while (slash_pos > 0 && path[slash_pos - 1] == kPathSeparator)
    --slash_pos;
  return path.substr(0, slash_pos);
}

}  // namespace

// DiskInterface ---------------------------------------------------------------

bool DiskInterface::MakeDirs(const std::string& path) {
  std::string dir = DirName(path);
  if (dir.empty())
    return true;  // Reached root; assume it's there.
  int mtime = Stat(dir);
  if (mtime < 0)
    return false;  // Error.
  if (mtime > 0)
    return true;  // Exists already; we're done.

  // Directory doesn't exist.  Try creating its parent first.
  bool success = MakeDirs(dir);
  if (!success)
    return false;
  return MakeDir(dir);
}

// RealDiskInterface -----------------------------------------------------------

int RealDiskInterface::Stat(const std::string& path) {
  struct stat st;
  if (stat(path.c_str(), &st) < 0) {
    if (errno == ENOENT) {
      return 0;
    } else {
      Error("stat(%s): %s", path.c_str(), strerror(errno));
      return -1;
    }
  }

  return st.st_mtime;
  return true;
}

bool RealDiskInterface::MakeDir(const std::string& path) {
  if (::MakeDir(path) < 0) {
    Error("mkdir(%s): %s", path.c_str(), strerror(errno));
    return false;
  }
  return true;
}

std::string RealDiskInterface::ReadFile(const std::string& path,
                                        std::string* err) {
  std::string contents;
  int ret = ::ReadFile(path, &contents, err);
  if (ret == -ENOENT) {
    // Swallow ENOENT.
    err->clear();
  }
  return contents;
}

int RealDiskInterface::RemoveFile(const std::string& path) {
  if (remove(path.c_str()) < 0) {
    switch (errno) {
      case ENOENT:
        return 1;
      default:
        Error("remove(%s): %s", path.c_str(), strerror(errno));
        return -1;
    }
  } else {
    return 0;
  }
}