| // Copyright 2012 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // See net/disk_cache/disk_cache.h for the public interface of the cache. |
| |
| #ifndef NET_DISK_CACHE_BLOCKFILE_MAPPED_FILE_H_ |
| #define NET_DISK_CACHE_BLOCKFILE_MAPPED_FILE_H_ |
| |
| #include <stddef.h> |
| |
| #include "base/memory/raw_ptr.h" |
| #include "base/memory/raw_ptr_exclusion.h" |
| #include "build/build_config.h" |
| #include "net/base/net_export.h" |
| #include "net/disk_cache/blockfile/file.h" |
| #include "net/disk_cache/blockfile/file_block.h" |
| #include "net/net_buildflags.h" |
| |
| namespace base { |
| class FilePath; |
| } |
| |
| namespace disk_cache { |
| |
| // This class implements a memory mapped file used to access block-files. The |
| // idea is that the header and bitmap will be memory mapped all the time, and |
| // the actual data for the blocks will be access asynchronously (most of the |
| // time). |
| class NET_EXPORT_PRIVATE MappedFile : public File { |
| public: |
| MappedFile() : File(true) {} |
| |
| MappedFile(const MappedFile&) = delete; |
| MappedFile& operator=(const MappedFile&) = delete; |
| |
| // Performs object initialization. name is the file to use, and size is the |
| // amount of data to memory map from the file. If size is 0, the whole file |
| // will be mapped in memory. |
| void* Init(const base::FilePath& name, size_t size); |
| |
| void* buffer() const { |
| return buffer_; |
| } |
| |
| // Loads or stores a given block from the backing file (synchronously). |
| bool Load(const FileBlock* block); |
| bool Store(const FileBlock* block); |
| |
| // Flush the memory-mapped section to disk (synchronously). |
| void Flush(); |
| |
| // Heats up the file system cache and make sure the file is fully |
| // readable (synchronously). |
| bool Preload(); |
| |
| private: |
| ~MappedFile() override; |
| |
| bool init_ = false; |
| #if BUILDFLAG(IS_WIN) |
| HANDLE section_; |
| #endif |
| // This field is not a raw_ptr<> because it is using mmap, MapViewOfFile or |
| // base::AllocPages directly. |
| // TODO(bartekn): This one has a malloc() path, consider rewriting after all. |
| RAW_PTR_EXCLUSION void* buffer_; // Address of the memory mapped buffer. |
| size_t view_size_; // Size of the memory pointed by buffer_. |
| #if BUILDFLAG(POSIX_BYPASS_MMAP) |
| raw_ptr<void> |
| snapshot_; // Copy of the buffer taken when it was last flushed. |
| #endif |
| }; |
| |
| // Helper class for calling Flush() on exit from the current scope. |
| class ScopedFlush { |
| public: |
| explicit ScopedFlush(MappedFile* file) : file_(file) {} |
| ~ScopedFlush() { |
| file_->Flush(); |
| } |
| private: |
| raw_ptr<MappedFile> file_; |
| }; |
| |
| } // namespace disk_cache |
| |
| #endif // NET_DISK_CACHE_BLOCKFILE_MAPPED_FILE_H_ |