mapped_file.h 2.5 KB

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  1. // Copyright 2017 The Chromium Authors. All rights reserved.
  2. // Use of this source code is governed by a BSD-style license that can be
  3. // found in the LICENSE file.
  4. #ifndef COMPONENTS_ZUCCHINI_MAPPED_FILE_H_
  5. #define COMPONENTS_ZUCCHINI_MAPPED_FILE_H_
  6. #include <stddef.h>
  7. #include <stdint.h>
  8. #include <string>
  9. #include "base/files/file.h"
  10. #include "base/files/file_path.h"
  11. #include "base/files/memory_mapped_file.h"
  12. #include "components/zucchini/buffer_view.h"
  13. namespace zucchini {
  14. // A file reader wrapper.
  15. class MappedFileReader {
  16. public:
  17. // Maps |file| to memory for reading. Also validates |file|. Errors are
  18. // available via HasError() and error().
  19. explicit MappedFileReader(base::File file);
  20. MappedFileReader(const MappedFileReader&) = delete;
  21. const MappedFileReader& operator=(const MappedFileReader&) = delete;
  22. const uint8_t* data() const { return buffer_.data(); }
  23. size_t length() const { return buffer_.length(); }
  24. zucchini::ConstBufferView region() const { return {data(), length()}; }
  25. bool HasError() { return !error_.empty() || !buffer_.IsValid(); }
  26. const std::string& error() { return error_; }
  27. private:
  28. std::string error_;
  29. base::MemoryMappedFile buffer_;
  30. };
  31. // A file writer wrapper. The target file is deleted on destruction unless
  32. // Keep() is called.
  33. class MappedFileWriter {
  34. public:
  35. // Maps |file| to memory for writing. |file_path| is needed for auto delete on
  36. // UNIX systems, but can be empty if auto delete is not needed. Errors are
  37. // available via HasError() and error().
  38. MappedFileWriter(const base::FilePath& file_path,
  39. base::File file,
  40. size_t length);
  41. MappedFileWriter(const MappedFileWriter&) = delete;
  42. const MappedFileWriter& operator=(const MappedFileWriter&) = delete;
  43. ~MappedFileWriter();
  44. uint8_t* data() { return buffer_.data(); }
  45. size_t length() const { return buffer_.length(); }
  46. zucchini::MutableBufferView region() { return {data(), length()}; }
  47. bool HasError() { return !error_.empty() || !buffer_.IsValid(); }
  48. const std::string& error() { return error_; }
  49. // Indicates that the file should not be deleted on destruction. Returns true
  50. // iff the operation succeeds.
  51. bool Keep();
  52. private:
  53. enum OnCloseDeleteBehavior {
  54. kKeep,
  55. kAutoDeleteOnClose,
  56. kManualDeleteOnClose
  57. };
  58. std::string error_;
  59. base::FilePath file_path_;
  60. base::File file_handle_;
  61. base::MemoryMappedFile buffer_;
  62. OnCloseDeleteBehavior delete_behavior_;
  63. };
  64. } // namespace zucchini
  65. #endif // COMPONENTS_ZUCCHINI_MAPPED_FILE_H_