1 files changed, 84 insertions, 0 deletions
diff --git a/dom/filesystem/FileSystemUtils.cpp b/dom/filesystem/FileSystemUtils.cpp
new file mode 100644
index 0000000000..5d4b391596
--- /dev/null
+++ b/dom/filesystem/FileSystemUtils.cpp
@@ -0,0 +1,84 @@
+/* -*- 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->EventTargetFor(TaskCategory::Other);
+  }
+
+  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