The Tor Browser: xpcom/io/FileUtilsWin.cpp@97036ab72558

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

     1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

     2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */

     3 /* This Source Code Form is subject to the terms of the Mozilla Public

     4  * License, v. 2.0. If a copy of the MPL was not distributed with this

     5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     7 #include "FileUtilsWin.h"

     9 #include <windows.h>

    10 #include <psapi.h>

    12 #include "nsWindowsHelpers.h"

    14 namespace {

    16 // Scoped type used by HandleToFilename

    17 struct ScopedMappedViewTraits

    18 {

    19   typedef void* type;

    20   static void* empty() { return nullptr; }

    21   static void release(void* ptr) { UnmapViewOfFile(ptr); }

    22 };

    23 typedef mozilla::Scoped<ScopedMappedViewTraits> ScopedMappedView;

    25 } // anonymous namespace

    27 namespace mozilla {

    29 bool

    30 HandleToFilename(HANDLE aHandle, const LARGE_INTEGER& aOffset,

    31                  nsAString& aFilename)

    32 {

    33   aFilename.Truncate();

    34   // This implementation is nice because it uses fully documented APIs that

    35   // are available on all Windows versions that we support.

    36   nsAutoHandle fileMapping(CreateFileMapping(aHandle, nullptr, PAGE_READONLY,

    37                                              0, 1, nullptr));

    38   if (!fileMapping) {

    39     return false;

    40   }

    41   ScopedMappedView view(MapViewOfFile(fileMapping, FILE_MAP_READ,

    42                                       aOffset.HighPart, aOffset.LowPart, 1));

    43   if (!view) {

    44     return false;

    45   }

    46   nsAutoString mappedFilename;

    47   DWORD len = 0;

    48   SetLastError(ERROR_SUCCESS);

    49   do {

    50     mappedFilename.SetLength(mappedFilename.Length() + MAX_PATH);

    51     len = GetMappedFileNameW(GetCurrentProcess(), view,

    52                              wwc(mappedFilename.BeginWriting()),

    53                              mappedFilename.Length());

    54   } while (!len && GetLastError() == ERROR_INSUFFICIENT_BUFFER);

    55   if (!len) {

    56     return false;

    57   }

    58   mappedFilename.Truncate(len);

    59   return NtPathToDosPath(mappedFilename, aFilename);

    60 }

    62 } // namespace mozilla

The Tor Browser / file revision

xpcom/io/FileUtilsWin.cpp@97036ab72558

xpcom/io/FileUtilsWin.cpp