1 files changed, 201 insertions, 0 deletions
diff --git a/dom/system/PathUtils.h b/dom/system/PathUtils.h
new file mode 100644
index 0000000000..05059d0d44
--- /dev/null
+++ b/dom/system/PathUtils.h
@@ -0,0 +1,201 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_PathUtils__
+#define mozilla_dom_PathUtils__
+
+#include "mozilla/DataMutex.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/MozPromise.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/Result.h"
+#include "mozilla/dom/Promise.h"
+#include "nsString.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+class ErrorResult;
+
+namespace dom {
+
+class PathUtils final {
+ public:
+  static void Filename(const GlobalObject&, const nsAString& aPath,
+                       nsString& aResult, ErrorResult& aErr);
+
+  static void Parent(const GlobalObject&, const nsAString& aPath,
+                     nsString& aResult, ErrorResult& aErr);
+
+  static void Join(const GlobalObject&, const Sequence<nsString>& aComponents,
+                   nsString& aResult, ErrorResult& aErr);
+
+  static void JoinRelative(const GlobalObject&, const nsAString& aBasePath,
+                           const nsAString& aRelativePath, nsString& aResult,
+                           ErrorResult& aErr);
+
+  static void CreateUniquePath(const GlobalObject&, const nsAString& aPath,
+                               nsString& aResult, ErrorResult& aErr);
+
+  static void Normalize(const GlobalObject&, const nsAString& aPath,
+                        nsString& aResult, ErrorResult& aErr);
+
+  static void Split(const GlobalObject&, const nsAString& aPath,
+                    nsTArray<nsString>& aResult, ErrorResult& aErr);
+
+  static void ToFileURI(const GlobalObject&, const nsAString& aPath,
+                        nsCString& aResult, ErrorResult& aErr);
+
+  static already_AddRefed<Promise> GetProfileDir(const GlobalObject& aGlobal,
+                                                 ErrorResult& aErr);
+
+  static already_AddRefed<Promise> GetLocalProfileDir(
+      const GlobalObject& aGlobal, ErrorResult& aErr);
+
+  static already_AddRefed<Promise> GetTempDir(const GlobalObject& aGlobal,
+                                              ErrorResult& aErr);
+
+ private:
+  class DirectoryCache;
+  friend class DirectoryCache;
+
+  static StaticDataMutex<Maybe<DirectoryCache>> sDirCache;
+};
+
+/**
+ * A cache of commonly used directories
+ */
+class PathUtils::DirectoryCache final {
+ public:
+  /**
+   * A directory that can be requested via |GetDirectory|.
+   */
+  enum class Directory {
+    /**
+     * The user's profile directory.
+     */
+    Profile,
+    /**
+     * The user's local profile directory.
+     */
+    LocalProfile,
+    /**
+     * The temporary directory for the process.
+     */
+    Temp,
+  };
+
+  DirectoryCache();
+  DirectoryCache(const DirectoryCache&) = delete;
+  DirectoryCache(DirectoryCache&&) = delete;
+  DirectoryCache& operator=(const DirectoryCache&) = delete;
+  DirectoryCache& operator=(DirectoryCache&&) = delete;
+
+  /**
+   * Ensure the cache is instantiated and schedule its destructor to run at
+   * shutdown.
+   *
+   * If the cache is already instantiated, this is a no-op.
+   *
+   * @param aCache The cache to ensure is instantiated.
+   */
+  static DirectoryCache& Ensure(Maybe<DirectoryCache>& aCache);
+
+  /**
+   * Request the path of a specific directory.
+   *
+   * If the directory has not been requested before, this may require a trip to
+   * the main thread to retrieve its path.
+   *
+   * @param aGlobalObject The JavaScript global.
+   * @param aErr The error result.
+   * @param aRequestedDir The directory for which the path is to be retrieved.
+   *
+   * @return A promise that resolves to the path of the requested directory.
+   */
+  already_AddRefed<Promise> GetDirectory(const GlobalObject& aGlobalObject,
+                                         ErrorResult& aErr,
+                                         const Directory aRequestedDir);
+
+ private:
+  using PopulateDirectoriesPromise = MozPromise<Ok, nsresult, false>;
+
+  /**
+   * Populate the directory cache entry for the requested directory.
+   *
+   * @param aRequestedDir The directory cache entry that was requested via
+   *                      |GetDirectory|.
+   *
+   * @return If the requested directory has not been populated, this returns a
+   *         promise that resolves when the population is complete.
+   *
+   *         If the requested directory has already been populated, it returns
+   *         nullptr instead.
+   */
+  already_AddRefed<PopulateDirectoriesPromise> PopulateDirectories(
+      const Directory aRequestedDir);
+
+  /**
+   * Initialize the requested directory cache entry.
+   *
+   * If |Directory::Temp| is requested, all cache entries will be populated.
+   * Otherwise, only the profile and local profile cache entries will be
+   * populated. The profile and local profile cache entries have no additional
+   * overhead for populating them, but the temp directory requires creating a
+   * directory on the main thread if it has not already happened.
+   *
+   * Must be called on the main thread.
+   *
+   * @param aRequestedDir The requested directory.
+   *
+   * @return The result of initializing directories.
+   */
+  nsresult PopulateDirectoriesImpl(const Directory aRequestedDir);
+
+  /**
+   * Resolve the internal PopulateDirectoriesPromise corresponding to
+   * |aRequestedDir| with the given result.
+   *
+   * This will allow all pending queries for the requested directory to resolve
+   * or be rejected.
+   *
+   * @param aRv The return value from PopulateDirectoriesImpl.
+   * @param aRequestedDir The requested directory cache entry. This is used to
+   *                      determine which internal MozPromiseHolder we are
+   * resolving.
+   */
+  void ResolvePopulateDirectoriesPromise(nsresult aRv,
+                                         const Directory aRequestedDir);
+
+  /**
+   * Resolve the given JS promise with the path of the requested directory
+   *
+   * Can only be called once the cache entry for the requested directory is
+   * populated.
+   *
+   * @param aPromise The JS promise to resolve.
+   * @param aRequestedDir The requested directory cache entry.
+   */
+  void ResolveWithDirectory(Promise* aPromise, const Directory aRequestedDir);
+
+  /**
+   * A promise that is resolved when |mProfileDir| and |mLocalProfileDir| are
+   * populated.
+   */
+  MozPromiseHolder<PopulateDirectoriesPromise> mProfileDirsPromise;
+  nsString mProfileDir;
+  nsString mLocalProfileDir;
+
+  /**
+   * A promise that is resolved when *all* cache entries are populated.
+   */
+  MozPromiseHolder<PopulateDirectoriesPromise> mAllDirsPromise;
+  nsString mTempDir;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif