11 files changed, 1251 insertions, 0 deletions

diff --git a/netwerk/protocol/file/FileChannelChild.cpp b/netwerk/protocol/file/FileChannelChild.cpp
new file mode 100644
index 0000000000..fa9cc00584
--- /dev/null
+++ b/netwerk/protocol/file/FileChannelChild.cpp
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 sw=2 sts=2 et 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 "FileChannelChild.h"
+
+#include "mozilla/Unused.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/net/NeckoChild.h"
+
+namespace mozilla {
+namespace net {
+
+NS_IMPL_ISUPPORTS_INHERITED(FileChannelChild, nsFileChannel, nsIChildChannel)
+
+FileChannelChild::FileChannelChild(nsIURI* uri) : nsFileChannel(uri) {}
+
+NS_IMETHODIMP
+FileChannelChild::ConnectParent(uint32_t id) {
+  mozilla::dom::ContentChild* cc =
+      static_cast<mozilla::dom::ContentChild*>(gNeckoChild->Manager());
+  if (cc->IsShuttingDown()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!gNeckoChild->SendPFileChannelConstructor(this, id)) {
+    return NS_ERROR_FAILURE;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+FileChannelChild::CompleteRedirectSetup(nsIStreamListener* listener) {
+  nsresult rv;
+
+  rv = AsyncOpen(listener);
+
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  if (CanSend()) {
+    Unused << Send__delete__(this);
+  }
+
+  return NS_OK;
+}
+
+}  // namespace net
+}  // namespace mozilla
diff --git a/netwerk/protocol/file/FileChannelChild.h b/netwerk/protocol/file/FileChannelChild.h
new file mode 100644
index 0000000000..e6d67b7d1c
--- /dev/null
+++ b/netwerk/protocol/file/FileChannelChild.h
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 sw=2 sts=2 et 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__net__FileChannelChild_h
+#define mozilla__net__FileChannelChild_h
+
+#include "nsFileChannel.h"
+#include "nsIChildChannel.h"
+#include "nsISupportsImpl.h"
+
+#include "mozilla/net/PFileChannelChild.h"
+
+namespace mozilla {
+namespace net {
+
+class FileChannelChild : public nsFileChannel,
+                         public nsIChildChannel,
+                         public PFileChannelChild {
+ public:
+  explicit FileChannelChild(nsIURI* uri);
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSICHILDCHANNEL
+
+ private:
+  ~FileChannelChild() = default;
+};
+
+}  // namespace net
+}  // namespace mozilla
+
+#endif /* mozilla__net__FileChannelChild_h */
diff --git a/netwerk/protocol/file/FileChannelParent.cpp b/netwerk/protocol/file/FileChannelParent.cpp
new file mode 100644
index 0000000000..e54fb11260
--- /dev/null
+++ b/netwerk/protocol/file/FileChannelParent.cpp
@@ -0,0 +1,105 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 sw=2 sts=2 et 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 "FileChannelParent.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/net/NeckoParent.h"
+#include "nsNetUtil.h"
+#include "nsIChannel.h"
+
+#ifdef FUZZING_SNAPSHOT
+#  define MOZ_ALWAYS_SUCCEEDS_FUZZING(...) (void)__VA_ARGS__
+#else
+#  define MOZ_ALWAYS_SUCCEEDS_FUZZING(...) MOZ_ALWAYS_SUCCEEDS(__VA_ARGS__)
+#endif
+
+namespace mozilla {
+namespace net {
+
+NS_IMPL_ISUPPORTS(FileChannelParent, nsIParentChannel, nsIStreamListener)
+
+bool FileChannelParent::Init(const uint64_t& aChannelId) {
+  nsCOMPtr<nsIChannel> channel;
+
+  MOZ_ALWAYS_SUCCEEDS_FUZZING(
+      NS_LinkRedirectChannels(aChannelId, this, getter_AddRefs(channel)));
+
+  return true;
+}
+
+NS_IMETHODIMP
+FileChannelParent::SetParentListener(ParentChannelListener* aListener) {
+  // Nothing to do.
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+FileChannelParent::NotifyClassificationFlags(uint32_t aClassificationFlags,
+                                             bool aIsThirdParty) {
+  // Nothing to do.
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+FileChannelParent::SetClassifierMatchedInfo(const nsACString& aList,
+                                            const nsACString& aProvider,
+                                            const nsACString& aFullHash) {
+  // nothing to do
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+FileChannelParent::SetClassifierMatchedTrackingInfo(
+    const nsACString& aLists, const nsACString& aFullHashes) {
+  // nothing to do
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+FileChannelParent::Delete() {
+  // Nothing to do.
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+FileChannelParent::GetRemoteType(nsACString& aRemoteType) {
+  if (!CanSend()) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  dom::PContentParent* pcp = Manager()->Manager();
+  aRemoteType = static_cast<dom::ContentParent*>(pcp)->GetRemoteType();
+  return NS_OK;
+}
+
+void FileChannelParent::ActorDestroy(ActorDestroyReason why) {}
+
+NS_IMETHODIMP
+FileChannelParent::OnStartRequest(nsIRequest* aRequest) {
+  // We don't have a way to prevent nsBaseChannel from calling AsyncOpen on
+  // the created nsDataChannel. We don't have anywhere to send the data in the
+  // parent, so abort the binding.
+  return NS_BINDING_ABORTED;
+}
+
+NS_IMETHODIMP
+FileChannelParent::OnStopRequest(nsIRequest* aRequest, nsresult aStatusCode) {
+  // See above.
+  MOZ_ASSERT(NS_FAILED(aStatusCode));
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+FileChannelParent::OnDataAvailable(nsIRequest* aRequest,
+                                   nsIInputStream* aInputStream,
+                                   uint64_t aOffset, uint32_t aCount) {
+  // See above.
+  MOZ_CRASH("Should never be called");
+}
+
+}  // namespace net
+}  // namespace mozilla
diff --git a/netwerk/protocol/file/FileChannelParent.h b/netwerk/protocol/file/FileChannelParent.h
new file mode 100644
index 0000000000..f2a10d8f87
--- /dev/null
+++ b/netwerk/protocol/file/FileChannelParent.h
@@ -0,0 +1,39 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=4 sw=2 sts=2 et 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__net__FileChannelParent_h
+#define mozilla__net__FileChannelParent_h
+
+#include "nsIParentChannel.h"
+#include "nsISupportsImpl.h"
+
+#include "mozilla/net/PFileChannelParent.h"
+
+namespace mozilla {
+namespace net {
+
+// In order to support HTTP redirects to file:, we need to implement the HTTP
+// redirection API, which requires a class that implements nsIParentChannel
+// and which calls NS_LinkRedirectChannels.
+class FileChannelParent : public nsIParentChannel, public PFileChannelParent {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIPARENTCHANNEL
+  NS_DECL_NSIREQUESTOBSERVER
+  NS_DECL_NSISTREAMLISTENER
+
+  [[nodiscard]] bool Init(const uint64_t& aChannelId);
+
+ private:
+  ~FileChannelParent() = default;
+
+  virtual void ActorDestroy(ActorDestroyReason why) override;
+};
+
+}  // namespace net
+}  // namespace mozilla
+
+#endif /* mozilla__net__FileChannelParent_h */
diff --git a/netwerk/protocol/file/moz.build b/netwerk/protocol/file/moz.build
new file mode 100644
index 0000000000..821e20e1c5
--- /dev/null
+++ b/netwerk/protocol/file/moz.build
@@ -0,0 +1,40 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "Networking: File")
+
+EXPORTS.mozilla.net += [
+    "FileChannelChild.h",
+    "FileChannelParent.h",
+    "nsFileProtocolHandler.h",
+]
+
+EXPORTS += [
+    "nsFileChannel.h",
+]
+
+XPIDL_SOURCES += [
+    "nsIFileChannel.idl",
+    "nsIFileProtocolHandler.idl",
+]
+
+XPIDL_MODULE = "necko_file"
+
+UNIFIED_SOURCES += [
+    "FileChannelChild.cpp",
+    "FileChannelParent.cpp",
+    "nsFileChannel.cpp",
+    "nsFileProtocolHandler.cpp",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
+
+LOCAL_INCLUDES += [
+    "/netwerk/base",
+]
diff --git a/netwerk/protocol/file/nsFileChannel.cpp b/netwerk/protocol/file/nsFileChannel.cpp
new file mode 100644
index 0000000000..6dc5f6780b
--- /dev/null
+++ b/netwerk/protocol/file/nsFileChannel.cpp
@@ -0,0 +1,514 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cin: */
+/* 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 "nsIOService.h"
+#include "nsFileChannel.h"
+#include "nsBaseContentStream.h"
+#include "nsDirectoryIndexStream.h"
+#include "nsThreadUtils.h"
+#include "nsTransportUtils.h"
+#include "nsStreamUtils.h"
+#include "nsMimeTypes.h"
+#include "nsNetUtil.h"
+#include "nsNetCID.h"
+#include "nsIOutputStream.h"
+#include "nsIFileStreams.h"
+#include "nsFileProtocolHandler.h"
+#include "nsProxyRelease.h"
+#include "nsIContentPolicy.h"
+#include "nsContentUtils.h"
+
+#include "nsIFileURL.h"
+#include "nsIURIMutator.h"
+#include "nsIFile.h"
+#include "nsIMIMEService.h"
+#include "prio.h"
+#include <algorithm>
+
+#include "mozilla/TaskQueue.h"
+#include "mozilla/Unused.h"
+
+using namespace mozilla;
+using namespace mozilla::net;
+
+//-----------------------------------------------------------------------------
+
+class nsFileCopyEvent : public Runnable {
+ public:
+  nsFileCopyEvent(nsIOutputStream* dest, nsIInputStream* source, int64_t len)
+      : mozilla::Runnable("nsFileCopyEvent"),
+        mDest(dest),
+        mSource(source),
+        mLen(len),
+        mStatus(NS_OK),
+        mInterruptStatus(NS_OK) {}
+
+  // Read the current status of the file copy operation.
+  nsresult Status() { return mStatus; }
+
+  // Call this method to perform the file copy synchronously.
+  void DoCopy();
+
+  // Call this method to perform the file copy on a background thread.  The
+  // callback is dispatched when the file copy completes.
+  nsresult Dispatch(nsIRunnable* callback, nsITransportEventSink* sink,
+                    nsIEventTarget* target);
+
+  // Call this method to interrupt a file copy operation that is occuring on
+  // a background thread.  The status parameter passed to this function must
+  // be a failure code and is set as the status of this file copy operation.
+  void Interrupt(nsresult status) {
+    NS_ASSERTION(NS_FAILED(status), "must be a failure code");
+    mInterruptStatus = status;
+  }
+
+  NS_IMETHOD Run() override {
+    DoCopy();
+    return NS_OK;
+  }
+
+ private:
+  nsCOMPtr<nsIEventTarget> mCallbackTarget;
+  nsCOMPtr<nsIRunnable> mCallback;
+  nsCOMPtr<nsITransportEventSink> mSink;
+  nsCOMPtr<nsIOutputStream> mDest;
+  nsCOMPtr<nsIInputStream> mSource;
+  int64_t mLen;
+  nsresult mStatus;           // modified on i/o thread only
+  nsresult mInterruptStatus;  // modified on main thread only
+};
+
+void nsFileCopyEvent::DoCopy() {
+  // We'll copy in chunks this large by default.  This size affects how
+  // frequently we'll check for interrupts.
+  const int32_t chunk =
+      nsIOService::gDefaultSegmentSize * nsIOService::gDefaultSegmentCount;
+
+  nsresult rv = NS_OK;
+
+  int64_t len = mLen, progress = 0;
+  while (len) {
+    // If we've been interrupted, then stop copying.
+    rv = mInterruptStatus;
+    if (NS_FAILED(rv)) break;
+
+    int32_t num = std::min((int32_t)len, chunk);
+
+    uint32_t result;
+    rv = mSource->ReadSegments(NS_CopySegmentToStream, mDest, num, &result);
+    if (NS_FAILED(rv)) break;
+    if (result != (uint32_t)num) {
+      // stopped prematurely (out of disk space)
+      rv = NS_ERROR_FILE_NO_DEVICE_SPACE;
+      break;
+    }
+
+    // Dispatch progress notification
+    if (mSink) {
+      progress += num;
+      mSink->OnTransportStatus(nullptr, NS_NET_STATUS_WRITING, progress, mLen);
+    }
+
+    len -= num;
+  }
+
+  if (NS_FAILED(rv)) mStatus = rv;
+
+  // Close the output stream before notifying our callback so that others may
+  // freely "play" with the file.
+  mDest->Close();
+
+  // Notify completion
+  if (mCallback) {
+    mCallbackTarget->Dispatch(mCallback, NS_DISPATCH_NORMAL);
+
+    // Release the callback on the target thread to avoid destroying stuff on
+    // the wrong thread.
+    NS_ProxyRelease("nsFileCopyEvent::mCallback", mCallbackTarget,
+                    mCallback.forget());
+  }
+}
+
+nsresult nsFileCopyEvent::Dispatch(nsIRunnable* callback,
+                                   nsITransportEventSink* sink,
+                                   nsIEventTarget* target) {
+  // Use the supplied event target for all asynchronous operations.
+
+  mCallback = callback;
+  mCallbackTarget = target;
+
+  // Build a coalescing proxy for progress events
+  nsresult rv =
+      net_NewTransportEventSinkProxy(getter_AddRefs(mSink), sink, target);
+
+  if (NS_FAILED(rv)) return rv;
+
+  // Dispatch ourselves to I/O thread pool...
+  nsCOMPtr<nsIEventTarget> pool =
+      do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID, &rv);
+  if (NS_FAILED(rv)) return rv;
+
+  return pool->Dispatch(this, NS_DISPATCH_NORMAL);
+}
+
+//-----------------------------------------------------------------------------
+
+// This is a dummy input stream that when read, performs the file copy.  The
+// copy happens on a background thread via mCopyEvent.
+
+class nsFileUploadContentStream : public nsBaseContentStream {
+ public:
+  NS_INLINE_DECL_REFCOUNTING_INHERITED(nsFileUploadContentStream,
+                                       nsBaseContentStream)
+
+  nsFileUploadContentStream(bool nonBlocking, nsIOutputStream* dest,
+                            nsIInputStream* source, int64_t len,
+                            nsITransportEventSink* sink)
+      : nsBaseContentStream(nonBlocking),
+        mCopyEvent(new nsFileCopyEvent(dest, source, len)),
+        mSink(sink) {}
+
+  bool IsInitialized() { return mCopyEvent != nullptr; }
+
+  NS_IMETHOD ReadSegments(nsWriteSegmentFun fun, void* closure, uint32_t count,
+                          uint32_t* result) override;
+  NS_IMETHOD AsyncWait(nsIInputStreamCallback* callback, uint32_t flags,
+                       uint32_t count, nsIEventTarget* target) override;
+
+ private:
+  virtual ~nsFileUploadContentStream() = default;
+
+  void OnCopyComplete();
+
+  RefPtr<nsFileCopyEvent> mCopyEvent;
+  nsCOMPtr<nsITransportEventSink> mSink;
+};
+
+NS_IMETHODIMP
+nsFileUploadContentStream::ReadSegments(nsWriteSegmentFun fun, void* closure,
+                                        uint32_t count, uint32_t* result) {
+  *result = 0;  // nothing is ever actually read from this stream
+
+  if (IsClosed()) return NS_OK;
+
+  if (IsNonBlocking()) {
+    // Inform the caller that they will have to wait for the copy operation to
+    // complete asynchronously.  We'll kick of the copy operation once they
+    // call AsyncWait.
+    return NS_BASE_STREAM_WOULD_BLOCK;
+  }
+
+  // Perform copy synchronously, and then close out the stream.
+  mCopyEvent->DoCopy();
+  nsresult status = mCopyEvent->Status();
+  CloseWithStatus(NS_FAILED(status) ? status : NS_BASE_STREAM_CLOSED);
+  return status;
+}
+
+NS_IMETHODIMP
+nsFileUploadContentStream::AsyncWait(nsIInputStreamCallback* callback,
+                                     uint32_t flags, uint32_t count,
+                                     nsIEventTarget* target) {
+  nsresult rv = nsBaseContentStream::AsyncWait(callback, flags, count, target);
+  if (NS_FAILED(rv) || IsClosed()) return rv;
+
+  if (IsNonBlocking()) {
+    nsCOMPtr<nsIRunnable> callback =
+        NewRunnableMethod("nsFileUploadContentStream::OnCopyComplete", this,
+                          &nsFileUploadContentStream::OnCopyComplete);
+    mCopyEvent->Dispatch(callback, mSink, target);
+  }
+
+  return NS_OK;
+}
+
+void nsFileUploadContentStream::OnCopyComplete() {
+  // This method is being called to indicate that we are done copying.
+  nsresult status = mCopyEvent->Status();
+
+  CloseWithStatus(NS_FAILED(status) ? status : NS_BASE_STREAM_CLOSED);
+}
+
+//-----------------------------------------------------------------------------
+
+nsFileChannel::nsFileChannel(nsIURI* uri) : mUploadLength(0), mFileURI(uri) {}
+
+nsresult nsFileChannel::Init() {
+  NS_ENSURE_STATE(mLoadInfo);
+
+  // If we have a link file, we should resolve its target right away.
+  // This is to protect against a same origin attack where the same link file
+  // can point to different resources right after the first resource is loaded.
+  nsCOMPtr<nsIFile> file;
+  nsCOMPtr<nsIURI> targetURI;
+#ifdef XP_WIN
+  nsAutoString fileTarget;
+#else
+  nsAutoCString fileTarget;
+#endif
+  nsCOMPtr<nsIFile> resolvedFile;
+  bool symLink;
+  nsCOMPtr<nsIFileURL> fileURL = do_QueryInterface(mFileURI);
+  if (fileURL && NS_SUCCEEDED(fileURL->GetFile(getter_AddRefs(file))) &&
+      NS_SUCCEEDED(file->IsSymlink(&symLink)) && symLink &&
+#ifdef XP_WIN
+      NS_SUCCEEDED(file->GetTarget(fileTarget)) &&
+      NS_SUCCEEDED(
+          NS_NewLocalFile(fileTarget, true, getter_AddRefs(resolvedFile))) &&
+#else
+      NS_SUCCEEDED(file->GetNativeTarget(fileTarget)) &&
+      NS_SUCCEEDED(NS_NewNativeLocalFile(fileTarget, true,
+                                         getter_AddRefs(resolvedFile))) &&
+#endif
+      NS_SUCCEEDED(
+          NS_NewFileURI(getter_AddRefs(targetURI), resolvedFile, nullptr))) {
+    // Make an effort to match up the query strings.
+    nsCOMPtr<nsIURL> origURL = do_QueryInterface(mFileURI);
+    nsCOMPtr<nsIURL> targetURL = do_QueryInterface(targetURI);
+    nsAutoCString queryString;
+    if (origURL && targetURL && NS_SUCCEEDED(origURL->GetQuery(queryString))) {
+      Unused
+          << NS_MutateURI(targetURI).SetQuery(queryString).Finalize(targetURI);
+    }
+
+    SetURI(targetURI);
+    SetOriginalURI(mFileURI);
+    mLoadInfo->SetResultPrincipalURI(targetURI);
+  } else {
+    SetURI(mFileURI);
+  }
+
+  return NS_OK;
+}
+
+nsresult nsFileChannel::MakeFileInputStream(nsIFile* file,
+                                            nsCOMPtr<nsIInputStream>& stream,
+                                            nsCString& contentType,
+                                            bool async) {
+  // we accept that this might result in a disk hit to stat the file
+  bool isDir;
+  nsresult rv = file->IsDirectory(&isDir);
+  if (NS_FAILED(rv)) {
+    if (rv == NS_ERROR_FILE_NOT_FOUND) {
+      CheckForBrokenChromeURL(mLoadInfo, OriginalURI());
+    }
+
+    if (async && (NS_ERROR_FILE_NOT_FOUND == rv)) {
+      // We don't return "Not Found" errors here. Since we could not find
+      // the file, it's not a directory anyway.
+      isDir = false;
+    } else {
+      return rv;
+    }
+  }
+
+  if (isDir) {
+    rv = nsDirectoryIndexStream::Create(file, getter_AddRefs(stream));
+    if (NS_SUCCEEDED(rv) && !HasContentTypeHint()) {
+      contentType.AssignLiteral(APPLICATION_HTTP_INDEX_FORMAT);
+    }
+  } else {
+    rv = NS_NewLocalFileInputStream(getter_AddRefs(stream), file, -1, -1,
+                                    async ? nsIFileInputStream::DEFER_OPEN : 0);
+    if (NS_SUCCEEDED(rv) && !HasContentTypeHint()) {
+      // Use file extension to infer content type
+      nsCOMPtr<nsIMIMEService> mime = do_GetService("@mozilla.org/mime;1", &rv);
+      if (NS_SUCCEEDED(rv)) {
+        mime->GetTypeFromFile(file, contentType);
+      }
+    }
+  }
+  return rv;
+}
+
+nsresult nsFileChannel::OpenContentStream(bool async, nsIInputStream** result,
+                                          nsIChannel** channel) {
+  // NOTE: the resulting file is a clone, so it is safe to pass it to the
+  //       file input stream which will be read on a background thread.
+  nsCOMPtr<nsIFile> file;
+  nsresult rv = GetFile(getter_AddRefs(file));
+  if (NS_FAILED(rv)) return rv;
+
+  nsCOMPtr<nsIFileProtocolHandler> fileHandler;
+  rv = NS_GetFileProtocolHandler(getter_AddRefs(fileHandler));
+  if (NS_FAILED(rv)) return rv;
+
+  nsCOMPtr<nsIURI> newURI;
+  if (NS_SUCCEEDED(fileHandler->ReadURLFile(file, getter_AddRefs(newURI))) ||
+      NS_SUCCEEDED(fileHandler->ReadShellLink(file, getter_AddRefs(newURI)))) {
+    nsCOMPtr<nsIChannel> newChannel;
+    rv = NS_NewChannel(getter_AddRefs(newChannel), newURI,
+                       nsContentUtils::GetSystemPrincipal(),
+                       nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
+                       nsIContentPolicy::TYPE_OTHER);
+
+    if (NS_FAILED(rv)) return rv;
+
+    *result = nullptr;
+    newChannel.forget(channel);
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIInputStream> stream;
+
+  if (mUploadStream) {
+    // Pass back a nsFileUploadContentStream instance that knows how to perform
+    // the file copy when "read" (the resulting stream in this case does not
+    // actually return any data).
+
+    nsCOMPtr<nsIOutputStream> fileStream;
+    rv = NS_NewLocalFileOutputStream(getter_AddRefs(fileStream), file,
+                                     PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE,
+                                     PR_IRUSR | PR_IWUSR);
+    if (NS_FAILED(rv)) return rv;
+
+    RefPtr<nsFileUploadContentStream> uploadStream =
+        new nsFileUploadContentStream(async, fileStream, mUploadStream,
+                                      mUploadLength, this);
+    if (!uploadStream || !uploadStream->IsInitialized()) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+    stream = std::move(uploadStream);
+
+    mContentLength = 0;
+
+    // Since there isn't any content to speak of we just set the content-type
+    // to something other than "unknown" to avoid triggering the content-type
+    // sniffer code in nsBaseChannel.
+    // However, don't override explicitly set types.
+    if (!HasContentTypeHint()) {
+      SetContentType(nsLiteralCString(APPLICATION_OCTET_STREAM));
+    }
+  } else {
+    nsAutoCString contentType;
+    rv = MakeFileInputStream(file, stream, contentType, async);
+    if (NS_FAILED(rv)) return rv;
+
+    EnableSynthesizedProgressEvents(true);
+
+    // fixup content length and type
+
+    // when we are called from asyncOpen, the content length fixup will be
+    // performed on a background thread and block the listener invocation via
+    // ListenerBlockingPromise method
+    if (!async && mContentLength < 0) {
+      rv = FixupContentLength(false);
+      if (NS_FAILED(rv)) {
+        return rv;
+      }
+    }
+
+    if (!contentType.IsEmpty()) {
+      SetContentType(contentType);
+    }
+  }
+
+  *result = nullptr;
+  stream.swap(*result);
+  return NS_OK;
+}
+
+nsresult nsFileChannel::ListenerBlockingPromise(BlockingPromise** aPromise) {
+  NS_ENSURE_ARG(aPromise);
+  *aPromise = nullptr;
+
+  if (mContentLength >= 0) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIEventTarget> sts(
+      do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID));
+  if (!sts) {
+    return FixupContentLength(true);
+  }
+
+  RefPtr<TaskQueue> taskQueue = TaskQueue::Create(sts.forget(), "FileChannel");
+  RefPtr<nsFileChannel> self = this;
+  RefPtr<BlockingPromise> promise =
+      mozilla::InvokeAsync(taskQueue, __func__, [self{std::move(self)}]() {
+        nsresult rv = self->FixupContentLength(true);
+        if (NS_FAILED(rv)) {
+          return BlockingPromise::CreateAndReject(rv, __func__);
+        }
+        return BlockingPromise::CreateAndResolve(NS_OK, __func__);
+      });
+
+  promise.forget(aPromise);
+  return NS_OK;
+}
+
+nsresult nsFileChannel::FixupContentLength(bool async) {
+  MOZ_ASSERT(mContentLength < 0);
+
+  nsCOMPtr<nsIFile> file;
+  nsresult rv = GetFile(getter_AddRefs(file));
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  int64_t size;
+  rv = file->GetFileSize(&size);
+  if (NS_FAILED(rv)) {
+    if (async && NS_ERROR_FILE_NOT_FOUND == rv) {
+      size = 0;
+    } else {
+      return rv;
+    }
+  }
+  mContentLength = size;
+
+  return NS_OK;
+}
+
+//-----------------------------------------------------------------------------
+// nsFileChannel::nsISupports
+
+NS_IMPL_ISUPPORTS_INHERITED(nsFileChannel, nsBaseChannel, nsIUploadChannel,
+                            nsIFileChannel)
+
+//-----------------------------------------------------------------------------
+// nsFileChannel::nsIFileChannel
+
+NS_IMETHODIMP
+nsFileChannel::GetFile(nsIFile** file) {
+  nsCOMPtr<nsIFileURL> fileURL = do_QueryInterface(URI());
+  NS_ENSURE_STATE(fileURL);
+
+  // This returns a cloned nsIFile
+  return fileURL->GetFile(file);
+}
+
+//-----------------------------------------------------------------------------
+// nsFileChannel::nsIUploadChannel
+
+NS_IMETHODIMP
+nsFileChannel::SetUploadStream(nsIInputStream* stream,
+                               const nsACString& contentType,
+                               int64_t contentLength) {
+  NS_ENSURE_TRUE(!Pending(), NS_ERROR_IN_PROGRESS);
+
+  if ((mUploadStream = stream)) {
+    mUploadLength = contentLength;
+    if (mUploadLength < 0) {
+      // Make sure we know how much data we are uploading.
+      uint64_t avail;
+      nsresult rv = mUploadStream->Available(&avail);
+      if (NS_FAILED(rv)) return rv;
+      // if this doesn't fit in the javascript MAX_SAFE_INTEGER
+      // pretend we don't know the size
+      mUploadLength = InScriptableRange(avail) ? avail : -1;
+    }
+  } else {
+    mUploadLength = -1;
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileChannel::GetUploadStream(nsIInputStream** result) {
+  *result = do_AddRef(mUploadStream).take();
+  return NS_OK;
+}
diff --git a/netwerk/protocol/file/nsFileChannel.h b/netwerk/protocol/file/nsFileChannel.h
new file mode 100644
index 0000000000..dcf0646f03
--- /dev/null
+++ b/netwerk/protocol/file/nsFileChannel.h
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cin: */
+/* 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 nsFileChannel_h__
+#define nsFileChannel_h__
+
+#include "nsBaseChannel.h"
+#include "nsIFileChannel.h"
+#include "nsIUploadChannel.h"
+
+class nsFileChannel : public nsBaseChannel,
+                      public nsIFileChannel,
+                      public nsIUploadChannel {
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIFILECHANNEL
+  NS_DECL_NSIUPLOADCHANNEL
+
+  explicit nsFileChannel(nsIURI* uri);
+
+  nsresult Init();
+
+ protected:
+  ~nsFileChannel() = default;
+
+  // Called to construct a blocking file input stream for the given file.  This
+  // method also returns a best guess at the content-type for the data stream.
+  // NOTE: If the channel has a type hint set, contentType will be left
+  // untouched. The caller should not use it in that case.
+  [[nodiscard]] nsresult MakeFileInputStream(nsIFile* file,
+                                             nsCOMPtr<nsIInputStream>& stream,
+                                             nsCString& contentType,
+                                             bool async);
+
+  [[nodiscard]] virtual nsresult OpenContentStream(
+      bool async, nsIInputStream** result, nsIChannel** channel) override;
+
+  // Implementing the pump blocking promise to fixup content length on a
+  // background thread prior to calling on mListener
+  virtual nsresult ListenerBlockingPromise(BlockingPromise** promise) override;
+
+ private:
+  nsresult FixupContentLength(bool async);
+
+  nsCOMPtr<nsIInputStream> mUploadStream;
+  int64_t mUploadLength;
+  nsCOMPtr<nsIURI> mFileURI;
+};
+
+#endif  // !nsFileChannel_h__
diff --git a/netwerk/protocol/file/nsFileProtocolHandler.cpp b/netwerk/protocol/file/nsFileProtocolHandler.cpp
new file mode 100644
index 0000000000..99e2f2bcc2
--- /dev/null
+++ b/netwerk/protocol/file/nsFileProtocolHandler.cpp
@@ -0,0 +1,266 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+// vim:ts=4 sw=2 sts=2 et cin:
+/* 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 "nsIFile.h"
+#include "nsFileProtocolHandler.h"
+#include "nsFileChannel.h"
+#include "nsStandardURL.h"
+#include "nsURLHelper.h"
+#include "nsIURIMutator.h"
+
+#include "nsNetUtil.h"
+
+#include "FileChannelChild.h"
+
+#include "mozilla/ResultExtensions.h"
+#include "mozilla/net/NeckoCommon.h"
+
+// URL file handling, copied and modified from
+// xpfe/components/bookmarks/src/nsBookmarksService.cpp
+#ifdef XP_WIN
+#  include <shlobj.h>
+#  include <intshcut.h>
+#  include "nsIFileURL.h"
+#  ifdef CompareString
+#    undef CompareString
+#  endif
+#endif
+
+// URL file handling for freedesktop.org
+#ifdef XP_UNIX
+#  include "nsINIParser.h"
+#  define DESKTOP_ENTRY_SECTION "Desktop Entry"
+#endif
+
+//-----------------------------------------------------------------------------
+
+nsresult nsFileProtocolHandler::Init() { return NS_OK; }
+
+NS_IMPL_ISUPPORTS(nsFileProtocolHandler, nsIFileProtocolHandler,
+                  nsIProtocolHandler, nsISupportsWeakReference)
+
+//-----------------------------------------------------------------------------
+// nsIProtocolHandler methods:
+
+#if defined(XP_WIN)
+NS_IMETHODIMP
+nsFileProtocolHandler::ReadURLFile(nsIFile* aFile, nsIURI** aURI) {
+  nsAutoString path;
+  nsresult rv = aFile->GetPath(path);
+  if (NS_FAILED(rv)) return rv;
+
+  if (path.Length() < 4) return NS_ERROR_NOT_AVAILABLE;
+  if (!StringTail(path, 4).LowerCaseEqualsLiteral(".url"))
+    return NS_ERROR_NOT_AVAILABLE;
+
+  HRESULT result;
+
+  rv = NS_ERROR_NOT_AVAILABLE;
+
+  IUniformResourceLocatorW* urlLink = nullptr;
+  result =
+      ::CoCreateInstance(CLSID_InternetShortcut, nullptr, CLSCTX_INPROC_SERVER,
+                         IID_IUniformResourceLocatorW, (void**)&urlLink);
+  if (SUCCEEDED(result) && urlLink) {
+    IPersistFile* urlFile = nullptr;
+    result = urlLink->QueryInterface(IID_IPersistFile, (void**)&urlFile);
+    if (SUCCEEDED(result) && urlFile) {
+      result = urlFile->Load(path.get(), STGM_READ);
+      if (SUCCEEDED(result)) {
+        LPWSTR lpTemp = nullptr;
+
+        // The URL this method will give us back seems to be already
+        // escaped. Hence, do not do escaping of our own.
+        result = urlLink->GetURL(&lpTemp);
+        if (SUCCEEDED(result) && lpTemp) {
+          rv = NS_NewURI(aURI, nsDependentString(lpTemp));
+          // free the string that GetURL alloc'd
+          CoTaskMemFree(lpTemp);
+        }
+      }
+      urlFile->Release();
+    }
+    urlLink->Release();
+  }
+  return rv;
+}
+
+#elif defined(XP_UNIX)
+NS_IMETHODIMP
+nsFileProtocolHandler::ReadURLFile(nsIFile* aFile, nsIURI** aURI) {
+  // We only support desktop files that end in ".desktop" like the spec says:
+  // http://standards.freedesktop.org/desktop-entry-spec/latest/ar01s02.html
+  nsAutoCString leafName;
+  nsresult rv = aFile->GetNativeLeafName(leafName);
+  if (NS_FAILED(rv) || !StringEndsWith(leafName, ".desktop"_ns)) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  bool isFile = false;
+  rv = aFile->IsFile(&isFile);
+  if (NS_FAILED(rv) || !isFile) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  nsINIParser parser;
+  rv = parser.Init(aFile);
+  if (NS_FAILED(rv)) return rv;
+
+  nsAutoCString type;
+  parser.GetString(DESKTOP_ENTRY_SECTION, "Type", type);
+  if (!type.EqualsLiteral("Link")) return NS_ERROR_NOT_AVAILABLE;
+
+  nsAutoCString url;
+  rv = parser.GetString(DESKTOP_ENTRY_SECTION, "URL", url);
+  if (NS_FAILED(rv) || url.IsEmpty()) return NS_ERROR_NOT_AVAILABLE;
+
+  return NS_NewURI(aURI, url);
+}
+
+#else   // other platforms
+NS_IMETHODIMP
+nsFileProtocolHandler::ReadURLFile(nsIFile* aFile, nsIURI** aURI) {
+  return NS_ERROR_NOT_AVAILABLE;
+}
+#endif  // ReadURLFile()
+
+NS_IMETHODIMP
+nsFileProtocolHandler::ReadShellLink(nsIFile* aFile, nsIURI** aURI) {
+#if defined(XP_WIN)
+  nsAutoString path;
+  MOZ_TRY(aFile->GetPath(path));
+
+  if (path.Length() < 4 ||
+      !StringTail(path, 4).LowerCaseEqualsLiteral(".lnk")) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+  RefPtr<IPersistFile> persistFile;
+  RefPtr<IShellLinkW> shellLink;
+  WCHAR lpTemp[MAX_PATH];
+  // Get a pointer to the IPersistFile interface.
+  if (FAILED(CoCreateInstance(CLSID_ShellLink, nullptr, CLSCTX_INPROC_SERVER,
+                              IID_IShellLinkW, getter_AddRefs(shellLink))) ||
+      FAILED(shellLink->QueryInterface(IID_IPersistFile,
+                                       getter_AddRefs(persistFile))) ||
+      FAILED(persistFile->Load(path.get(), STGM_READ)) ||
+      FAILED(shellLink->Resolve(nullptr, SLR_NO_UI)) ||
+      FAILED(shellLink->GetPath(lpTemp, MAX_PATH, nullptr, SLGP_UNCPRIORITY))) {
+    return NS_ERROR_FAILURE;
+  }
+  nsCOMPtr<nsIFile> linkedFile;
+  MOZ_TRY(NS_NewLocalFile(nsDependentString(lpTemp), false,
+                          getter_AddRefs(linkedFile)));
+  return NS_NewFileURI(aURI, linkedFile);
+#else
+  return NS_ERROR_NOT_AVAILABLE;
+#endif
+}
+
+NS_IMETHODIMP
+nsFileProtocolHandler::GetScheme(nsACString& result) {
+  result.AssignLiteral("file");
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileProtocolHandler::NewChannel(nsIURI* uri, nsILoadInfo* aLoadInfo,
+                                  nsIChannel** result) {
+  nsresult rv;
+
+  RefPtr<nsFileChannel> chan;
+  if (mozilla::net::IsNeckoChild()) {
+    chan = new mozilla::net::FileChannelChild(uri);
+  } else {
+    chan = new nsFileChannel(uri);
+  }
+
+  // set the loadInfo on the new channel ; must do this
+  // before calling Init() on it, since it needs the load
+  // info be already set.
+  rv = chan->SetLoadInfo(aLoadInfo);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  rv = chan->Init();
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  chan.forget(result);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileProtocolHandler::AllowPort(int32_t port, const char* scheme,
+                                 bool* result) {
+  // don't override anything.
+  *result = false;
+  return NS_OK;
+}
+
+//-----------------------------------------------------------------------------
+// nsIFileProtocolHandler methods:
+
+NS_IMETHODIMP
+nsFileProtocolHandler::NewFileURI(nsIFile* aFile, nsIURI** aResult) {
+  NS_ENSURE_ARG_POINTER(aFile);
+
+  RefPtr<nsIFile> file(aFile);
+  // NOTE: the origin charset is assigned the value of the platform
+  // charset by the SetFile method.
+  return NS_MutateURI(new mozilla::net::nsStandardURL::Mutator())
+      .Apply(&nsIFileURLMutator::SetFile, file)
+      .Finalize(aResult);
+}
+
+NS_IMETHODIMP
+nsFileProtocolHandler::NewFileURIMutator(nsIFile* aFile,
+                                         nsIURIMutator** aResult) {
+  NS_ENSURE_ARG_POINTER(aFile);
+  nsresult rv;
+
+  nsCOMPtr<nsIURIMutator> mutator = new mozilla::net::nsStandardURL::Mutator();
+  nsCOMPtr<nsIFileURLMutator> fileMutator = do_QueryInterface(mutator, &rv);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  // NOTE: the origin charset is assigned the value of the platform
+  // charset by the SetFile method.
+  rv = fileMutator->SetFile(aFile);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  mutator.forget(aResult);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsFileProtocolHandler::GetURLSpecFromFile(nsIFile* file, nsACString& result) {
+  NS_ENSURE_ARG_POINTER(file);
+  return net_GetURLSpecFromFile(file, result);
+}
+
+NS_IMETHODIMP
+nsFileProtocolHandler::GetURLSpecFromActualFile(nsIFile* file,
+                                                nsACString& result) {
+  NS_ENSURE_ARG_POINTER(file);
+  return net_GetURLSpecFromActualFile(file, result);
+}
+
+NS_IMETHODIMP
+nsFileProtocolHandler::GetURLSpecFromDir(nsIFile* file, nsACString& result) {
+  NS_ENSURE_ARG_POINTER(file);
+  return net_GetURLSpecFromDir(file, result);
+}
+
+NS_IMETHODIMP
+nsFileProtocolHandler::GetFileFromURLSpec(const nsACString& spec,
+                                          nsIFile** result) {
+  return net_GetFileFromURLSpec(spec, result);
+}
diff --git a/netwerk/protocol/file/nsFileProtocolHandler.h b/netwerk/protocol/file/nsFileProtocolHandler.h
new file mode 100644
index 0000000000..ff2b30634a
--- /dev/null
+++ b/netwerk/protocol/file/nsFileProtocolHandler.h
@@ -0,0 +1,28 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 nsFileProtocolHandler_h__
+#define nsFileProtocolHandler_h__
+
+#include "nsIFileProtocolHandler.h"
+#include "nsWeakReference.h"
+
+class nsIURIMutator;
+
+class nsFileProtocolHandler : public nsIFileProtocolHandler,
+                              public nsSupportsWeakReference {
+  virtual ~nsFileProtocolHandler() = default;
+
+ public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIPROTOCOLHANDLER
+  NS_DECL_NSIFILEPROTOCOLHANDLER
+
+  nsFileProtocolHandler() = default;
+
+  [[nodiscard]] nsresult Init();
+};
+
+#endif  // !nsFileProtocolHandler_h__
diff --git a/netwerk/protocol/file/nsIFileChannel.idl b/netwerk/protocol/file/nsIFileChannel.idl
new file mode 100644
index 0000000000..e5fcdecb4c
--- /dev/null
+++ b/netwerk/protocol/file/nsIFileChannel.idl
@@ -0,0 +1,17 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "nsISupports.idl"
+
+interface nsIFile;
+
+/**
+ * nsIFileChannel
+ */
+[scriptable, uuid(06169120-136d-45a5-b535-498f1f755ab7)]
+interface nsIFileChannel : nsISupports
+{
+    readonly attribute nsIFile file;
+};
diff --git a/netwerk/protocol/file/nsIFileProtocolHandler.idl b/netwerk/protocol/file/nsIFileProtocolHandler.idl
new file mode 100644
index 0000000000..d470dcee2a
--- /dev/null
+++ b/netwerk/protocol/file/nsIFileProtocolHandler.idl
@@ -0,0 +1,102 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 "nsIProtocolHandler.idl"
+
+interface nsIFile;
+interface nsIURIMutator;
+
+[scriptable, uuid(1fb25bd5-4354-4dcd-8d97-621b7b3ed2e4)]
+interface nsIFileProtocolHandler : nsIProtocolHandler
+{
+    /**
+     * This method constructs a new file URI
+     *
+     * @param aFile nsIFile
+     * @return reference to a new nsIURI object
+     */
+    nsIURI newFileURI(in nsIFile aFile);
+
+    /**
+     * This method constructs a new file URI, and returns a URI mutator
+     * that has not yet been finalized, allowing the URI to be changed without
+     * being cloned.
+     *
+     * @param aFile nsIFile
+     * @return reference to a new nsIURIMutator object
+     */
+    nsIURIMutator newFileURIMutator(in nsIFile file);
+
+    /**
+     * DEPRECATED, AVOID IF AT ALL POSSIBLE.
+     *
+     * Calling this will cause IO on the calling thread, to determine
+     * if the file is a directory or file, and based on that behaves as
+     * if you called getURLSpecFromDir or getURLSpecFromActualFile,
+     * respectively. This IO may take multiple seconds (e.g. for network
+     * paths, slow external drives that need to be woken up, etc.).
+     *
+     * Usually, the caller should *know* that the `file` argument is
+     * either a directory (in which case it should call getURLSpecFromDir)
+     * or a non-directory file (in which case it should call
+     * getURLSpecFromActualFile), and not need to call this method.
+     */
+    [noscript] AUTF8String getURLSpecFromFile(in nsIFile file);
+
+    /**
+     * Converts a non-directory nsIFile to the corresponding URL string.
+     * NOTE: under some platforms this is a lossy conversion (e.g., Mac
+     * Carbon build). If the nsIFile is a local file, then the result
+     * will be a file:// URL string.
+     *
+     * The resulting string may contain URL-escaped characters.
+     *
+     * Should only be called on files which are not directories. If
+     * called on directories, the resulting URL may lack a trailing slash
+     * and cause relative URLs in such a document to misbehave.
+     */
+    AUTF8String getURLSpecFromActualFile(in nsIFile file);
+
+    /**
+     * Converts a directory nsIFile to the corresponding URL string.
+     * NOTE: under some platforms this is a lossy conversion (e.g., Mac
+     * Carbon build). If the nsIFile is a local file, then the result
+     * will be a file:// URL string.
+     *
+     * The resulting string may contain URL-escaped characters.
+     *
+     * Should only be called on files which are directories (will enforce
+     * the URL ends with a slash).
+     */
+    AUTF8String getURLSpecFromDir(in nsIFile file);
+
+    /**
+     * Converts the URL string into the corresponding nsIFile if possible.
+     * A local file will be created if the URL string begins with file://.
+     */
+    nsIFile getFileFromURLSpec(in AUTF8String url);
+
+    /**
+     * Takes a local file and tries to interpret it as an internet shortcut
+     * (e.g. .url files on windows).
+     * @param file The local file to read
+     * @return The URI the file refers to
+     *
+     * @throw NS_ERROR_NOT_AVAILABLE if the OS does not support such files.
+     * @throw NS_ERROR_NOT_AVAILABLE if this file is not an internet shortcut.
+     */
+    nsIURI readURLFile(in nsIFile file);
+
+    /**
+     * Takes a local file and tries to interpret it as a shell link file
+     * (.lnk files on Windows)
+     * @param file The local file to read
+     * @return The URI the file refers to
+     *
+     * @throw NS_ERROR_NOT_AVAILABLE if the OS does not support such files.
+     * @throw NS_ERROR_NOT_AVAILABLE if this file is not a shell link.
+     */
+    nsIURI readShellLink(in nsIFile file);
+};