| 1 | # s3-bsync Copyright (c) 2022 Joshua Stockin |
| 2 | # <https://joshstock.in> |
| 3 | # <https://git.joshstock.in/s3-bsync> |
| 4 | # |
| 5 | # This software is licensed and distributed under the terms of the MIT License. |
| 6 | # See the MIT License in the LICENSE file of this project's root folder. |
| 7 | # |
| 8 | # This comment block and its contents, including this disclaimer, MUST be |
| 9 | # preserved in all copies or distributions of this software's source. |
| 10 |
|
| 11 | import os |
| 12 |
|
| 13 | import logging |
| 14 |
|
| 15 | import s3_bsync.classes |
| 16 |
|
| 17 | logger = logging.getLogger(__name__) |
| 18 |
|
| 19 | __all__ = ["syncfile"] |
| 20 |
|
| 21 |
|
| 22 | CONTROL_BYTES = { |
| 23 | ["SIGNATURE"]: b"\x9D\x9F\x53\x33", |
| 24 | ["BUCKET_BEGIN"]: b"\x90", |
| 25 | ["BUCKET_END"]: b"\x91", |
| 26 | ["DIRECTORY_BEGIN"]: b"\x92", |
| 27 | ["DIRECTORY_END"]: b"\x93", |
| 28 | ["OBJECT_BEGIN"]: b"\x94", |
| 29 | ["OBJECT_END"]: b"\x95", |
| 30 | ["ETAG_MD5"]: b"\x96", |
| 31 | ["ETAG_OTHER"]: b"\x97", |
| 32 | ["METADATA_BEGIN"]: b"\x9A", |
| 33 | ["METADATA_END"]: b"\x9B", |
| 34 | } |
| 35 |
|
| 36 | CURRENT_VERSION = 1 |
| 37 | ENDIANNESS = "little" |
| 38 |
|
| 39 |
|
| 40 | class CorruptSyncfileException(Exception): |
| 41 | """Exception passed by syncfile class when experiencing errors deserializing a supplied s3sync file.""" |
| 42 |
|
| 43 |
|
| 44 | class syncfile: |
| 45 | file_path = None |
| 46 | file = None |
| 47 | file_version = 0 |
| 48 | last_synced_time = 0 |
| 49 | tracked_buckets = {} |
| 50 |
|
| 51 | def __init__(self, state_file: str): |
| 52 | self.file_path = state_file |
| 53 | self.file = open(state_file, "wb+") |
| 54 | logger.debug(f"Opened s3sync state file at {state_file}") |
| 55 |
|
| 56 | def deserialize(): |
| 57 | f = self.file |
| 58 | logger.debug(f"Deserializing file {f}") |
| 59 | f.seek(0) |
| 60 |
|
| 61 | def get_string(): |
| 62 | return "".join(iter(lambda: f.read(1), "\x00")) |
| 63 |
|
| 64 | b = f.read(4) |
| 65 | if b is not CONTROL_BYTES["SIGNATURE"]: |
| 66 | raise CorruptSyncfileException( |
| 67 | "Inputted file signature bytes do not match expected s3state file signature (file corrupted or not an s3sync file format)" |
| 68 | ) |
| 69 |
|
| 70 | self.file_version = int(f.read(1)) |
| 71 | if self.file_version is 0 or self.file_version >= 1: |
| 72 | raise CorruptSyncfileException( |
| 73 | f"File version outside expected range (1..{CURRENT_VERSION}) (corrupt file)" |
| 74 | ) |
| 75 |
|
| 76 | b = f.read(1) |
| 77 | if b is not CONTROL_BYTES["METADATA_BEGIN"]: |
| 78 | raise CorruptSyncfileException( |
| 79 | "Expected metadata block begin byte not found (corrupt file)" |
| 80 | ) |
| 81 | if self.file_version <= 1: |
| 82 | self.last_synced_time = int.from_bytes(b.read(8), byteorder=ENDIANNESS) |
| 83 | logger.debug(f"Last synced time reported as {self.last_synced_time}") |
| 84 |
|
| 85 | b = f.read(1) |
| 86 | if b is not CONTROL_BYTES["METADATA_END"]: |
| 87 | raise CorruptSyncfileException( |
| 88 | "Expected metadata block end byte not found (corrupt file)" |
| 89 | ) |
| 90 |
|
| 91 | while b := f.read(1): |
| 92 | if b is not CONTROL_BYTES["BUCKET_BEGIN"]: |
| 93 | raise CorruptSyncfileException( |
| 94 | b"Unexpected control byte {b} detected (corrupt file)" |
| 95 | ) |
| 96 | bucket_name = get_string() |
| 97 | bucket = classes.bucket(bucket_name) |
| 98 |
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