| // Copyright 2017 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. |
| |
| #ifndef BASE_FILE_DESCRIPTOR_STORE_H_ |
| #define BASE_FILE_DESCRIPTOR_STORE_H_ |
| |
| #include <map> |
| #include <string> |
| |
| #include "base/files/memory_mapped_file.h" |
| #include "base/files/scoped_file.h" |
| |
| namespace base { |
| |
| // The file descriptor store is used to associate file descriptors with keys |
| // that must be unique. |
| // It is used to share file descriptors from a process to its child. |
| class BASE_EXPORT FileDescriptorStore { |
| public: |
| FileDescriptorStore(const FileDescriptorStore&) = delete; |
| FileDescriptorStore& operator=(const FileDescriptorStore&) = delete; |
| struct Descriptor { |
| Descriptor(const std::string& key, base::ScopedFD fd); |
| Descriptor(const std::string& key, |
| base::ScopedFD fd, |
| base::MemoryMappedFile::Region region); |
| Descriptor(Descriptor&& other); |
| ~Descriptor(); |
| |
| Descriptor& operator=(Descriptor&& other) = default; |
| |
| // Globally unique key. |
| std::string key; |
| // Actual FD. |
| base::ScopedFD fd; |
| // Optional region, defaults to kWholeFile. |
| base::MemoryMappedFile::Region region; |
| }; |
| using Mapping = std::map<std::string, Descriptor>; |
| |
| // Returns the singleton instance of FileDescriptorStore. |
| static FileDescriptorStore& GetInstance(); |
| |
| // Gets a descriptor given a key and also populates |region|. |
| // It is a fatal error if the key is not known. |
| base::ScopedFD TakeFD(const std::string& key, |
| base::MemoryMappedFile::Region* region); |
| |
| // Gets a descriptor given a key. Returns an empty ScopedFD on error. |
| base::ScopedFD MaybeTakeFD(const std::string& key, |
| base::MemoryMappedFile::Region* region); |
| |
| // Sets the descriptor for the given |key|. This sets the region associated |
| // with |key| to kWholeFile. |
| void Set(const std::string& key, base::ScopedFD fd); |
| |
| // Sets the descriptor and |region| for the given |key|. |
| void Set(const std::string& key, |
| base::ScopedFD fd, |
| base::MemoryMappedFile::Region region); |
| |
| private: |
| FileDescriptorStore(); |
| ~FileDescriptorStore(); |
| |
| Mapping descriptors_; |
| }; |
| |
| } // namespace base |
| |
| #endif // BASE_FILE_DESCRIPTOR_STORE_H_ |