FileSystemUtils.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
 * You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/dom/FileSystemUtils.h"
#include "nsCharSeparatedTokenizer.h"
#include "nsIEventTarget.h"
#include "nsThreadUtils.h"

namespace mozilla::dom {

/* static */
bool FileSystemUtils::IsDescendantPath(const nsAString& aPath,
                                       const nsAString& aDescendantPath) {
  // Check the sub-directory path to see if it has the parent path as prefix.
  if (!aDescendantPath.Equals(aPath) &&
      !StringBeginsWith(aDescendantPath, aPath)) {
    return false;
  }

  return true;
}

/* static */
bool FileSystemUtils::IsValidRelativeDOMPath(const nsAString& aPath,
                                             nsTArray<nsString>& aParts) {
  // We don't allow empty relative path to access the root.
  if (aPath.IsEmpty()) {
    return false;
  }

  // Leading and trailing "/" are not allowed.
  if (aPath.First() == FILESYSTEM_DOM_PATH_SEPARATOR_CHAR ||
      aPath.Last() == FILESYSTEM_DOM_PATH_SEPARATOR_CHAR) {
    return false;
  }

  constexpr auto kCurrentDir = u"."_ns;
  constexpr auto kParentDir = u".."_ns;

  // Split path and check each path component.
  for (const nsAString& pathComponent :
       nsCharSeparatedTokenizerTemplate<NS_TokenizerIgnoreNothing>{
           aPath, FILESYSTEM_DOM_PATH_SEPARATOR_CHAR}
           .ToRange()) {
    // The path containing empty components, such as "foo//bar", is invalid.
    // We don't allow paths, such as "../foo", "foo/./bar" and "foo/../bar",
    // to walk up the directory.
    if (pathComponent.IsEmpty() || pathComponent.Equals(kCurrentDir) ||
        pathComponent.Equals(kParentDir)) {
      return false;
    }

    aParts.AppendElement(pathComponent);
  }

  return true;
}

/* static */
nsresult FileSystemUtils::DispatchRunnable(
    nsIGlobalObject* aGlobal, already_AddRefed<nsIRunnable>&& aRunnable) {
  nsCOMPtr<nsIRunnable> runnable = aRunnable;

  nsCOMPtr<nsIEventTarget> target;
  if (!aGlobal) {
    target = GetMainThreadSerialEventTarget();
  } else {
    target = aGlobal->SerialEventTarget();
  }

  MOZ_ASSERT(target);

  nsresult rv = target->Dispatch(runnable.forget(), NS_DISPATCH_NORMAL);
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return rv;
  }

  return NS_OK;
}

}  // namespace mozilla::dom