Improve process launch handle sharing API.

content/browser/posix_file_descriptor_info_impl.cc

+// Copyright (c) 2012 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 "content/browser/posix_file_descriptor_info_impl.h"
+
+#include <utility>
+
+#include "base/memory/ptr_util.h"
+#include "base/stl_util.h"
+
+namespace content {
+
+// static
+std::unique_ptr<PosixFileDescriptorInfo> PosixFileDescriptorInfoImpl::Create() {
+  return std::unique_ptr<PosixFileDescriptorInfo>(
+      new PosixFileDescriptorInfoImpl());
+}
+
+PosixFileDescriptorInfoImpl::PosixFileDescriptorInfoImpl() {}
+
+PosixFileDescriptorInfoImpl::~PosixFileDescriptorInfoImpl() {}
+
+void PosixFileDescriptorInfoImpl::Share(int id, base::PlatformFile fd) {
+  ShareWithRegion(id, fd, base::MemoryMappedFile::Region::kWholeFile);
+}
+
+void PosixFileDescriptorInfoImpl::ShareWithRegion(
+    int id,
+    base::PlatformFile fd,
+    const base::MemoryMappedFile::Region& region) {
+  AddToMapping(id, fd, region);
+}
+
+void PosixFileDescriptorInfoImpl::Transfer(int id, base::ScopedFD fd) {
+  AddToMapping(id, fd.get(), base::MemoryMappedFile::Region::kWholeFile);
+  owned_descriptors_.push_back(std::move(fd));
+}
+
+base::PlatformFile PosixFileDescriptorInfoImpl::GetFDAt(size_t i) const {
+  return mapping_[i].first;
+}
+
+int PosixFileDescriptorInfoImpl::GetIDAt(size_t i) const {
+  return mapping_[i].second;
+}
+
+const base::MemoryMappedFile::Region& PosixFileDescriptorInfoImpl::GetRegionAt(
+    size_t i) const {
+  auto iter = ids_to_regions_.find(GetIDAt(i));
+  return (iter != ids_to_regions_.end())
+             ? iter->second
+             : base::MemoryMappedFile::Region::kWholeFile;
+}
+
+size_t PosixFileDescriptorInfoImpl::GetMappingSize() const {
+  return mapping_.size();
+}
+
+bool PosixFileDescriptorInfoImpl::HasID(int id) const {
+  for (unsigned i = 0; i < mapping_.size(); ++i) {
+    if (mapping_[i].second == id)
+      return true;
+  }
+
+  return false;
+}
+
+bool PosixFileDescriptorInfoImpl::OwnsFD(base::PlatformFile file) const {
+  return base::ContainsValue(owned_descriptors_, file);
+}
+
+base::ScopedFD PosixFileDescriptorInfoImpl::ReleaseFD(base::PlatformFile file) {
+  DCHECK(OwnsFD(file));
+
+  base::ScopedFD fd;
+  auto found =
+      std::find(owned_descriptors_.begin(), owned_descriptors_.end(), file);
+
+  std::swap(*found, fd);
+  owned_descriptors_.erase(found);
+
+  return fd;
+}
+
+void PosixFileDescriptorInfoImpl::AddToMapping(
+    int id,
+    base::PlatformFile fd,
+    const base::MemoryMappedFile::Region& region) {
+  DCHECK(!HasID(id));
+  mapping_.push_back(std::make_pair(fd, id));
+  if (region != base::MemoryMappedFile::Region::kWholeFile)
+    ids_to_regions_[id] = region;
+}
+
+const base::FileHandleMappingVector& PosixFileDescriptorInfoImpl::GetMapping()
+    const {
+  return mapping_;
+}
+
+base::FileHandleMappingVector
+PosixFileDescriptorInfoImpl::GetMappingWithIDAdjustment(int delta) const {
+  base::FileHandleMappingVector result(mapping_);
+
+  // Adding delta to each ID.
+  for (size_t i = 0; i < result.size(); ++i)
+    result[i].second += delta;
+  return result;
+}
+
+}  // namespace content