Move FileDescriptorShuffle to base/posix. This file is very posix-specific.

base/file_descriptor_shuffle.cc

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "base/file_descriptor_shuffle.h"
-
-#include <unistd.h>
-#include <stddef.h>
-#include <ostream>
-
-#include "base/eintr_wrapper.h"
-#include "base/logging.h"
-
-namespace base {
-
-bool PerformInjectiveMultimapDestructive(
-    InjectiveMultimap* m, InjectionDelegate* delegate) {
-  static const size_t kMaxExtraFDs = 16;
-  int extra_fds[kMaxExtraFDs];
-  unsigned next_extra_fd = 0;
-
-  // DANGER: this function may not allocate.
-
-  for (InjectiveMultimap::iterator i = m->begin(); i != m->end(); ++i) {
-    int temp_fd = -1;
-
-    // We DCHECK the injectiveness of the mapping.
-    for (InjectiveMultimap::iterator j = i + 1; j != m->end(); ++j) {
-      DCHECK(i->dest != j->dest) << "Both fd " << i->source
-          << " and " << j->source << " map to " << i->dest;
-    }
-
-    const bool is_identity = i->source == i->dest;
-
-    for (InjectiveMultimap::iterator j = i + 1; j != m->end(); ++j) {
-      if (!is_identity && i->dest == j->source) {
-        if (temp_fd == -1) {
-          if (!delegate->Duplicate(&temp_fd, i->dest))
-            return false;
-          if (next_extra_fd < kMaxExtraFDs) {
-            extra_fds[next_extra_fd++] = temp_fd;
-          } else {
-            RAW_LOG(ERROR, "PerformInjectiveMultimapDestructive overflowed "
-                           "extra_fds. Leaking file descriptors!");
-          }
-        }
-
-        j->source = temp_fd;
-        j->close = false;
-      }
-
-      if (i->close && i->source == j->dest)
-        i->close = false;
-
-      if (i->close && i->source == j->source) {
-        i->close = false;
-        j->close = true;
-      }
-    }
-
-    if (!is_identity) {
-      if (!delegate->Move(i->source, i->dest))
-        return false;
-    }
-
-    if (!is_identity && i->close)
-      delegate->Close(i->source);
-  }
-
-  for (unsigned i = 0; i < next_extra_fd; i++)
-    delegate->Close(extra_fds[i]);
-
-  return true;
-}
-
-bool PerformInjectiveMultimap(const InjectiveMultimap& m_in,
-                              InjectionDelegate* delegate) {
-  InjectiveMultimap m(m_in);
-  return PerformInjectiveMultimapDestructive(&m, delegate);
-}
-
-bool FileDescriptorTableInjection::Duplicate(int* result, int fd) {
-  *result = HANDLE_EINTR(dup(fd));
-  return *result >= 0;
-}
-
-bool FileDescriptorTableInjection::Move(int src, int dest) {
-  return HANDLE_EINTR(dup2(src, dest)) != -1;
-}
-
-void FileDescriptorTableInjection::Close(int fd) {
-  int ret = HANDLE_EINTR(close(fd));
-  DPCHECK(ret == 0);
-}
-
-}  // namespace base