36 lines
945 B
Python
36 lines
945 B
Python
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import hashlib
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from io import UnsupportedOperation
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HASH_READ_SIZE = 2**18 # 256k - matches `hashlib.file_digest`
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def hash_filelike(filelike):
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"""
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Compute the hash of a file-like object, without loading it all into memory.
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"""
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file_pos = 0
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if hasattr(filelike, "tell"):
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file_pos = filelike.tell()
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try:
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# Reset file handler to the start of the file so we hash it all
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filelike.seek(0)
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except (AttributeError, UnsupportedOperation):
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pass
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if hasattr(hashlib, "file_digest"):
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hasher = hashlib.file_digest(filelike, hashlib.sha1)
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else:
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hasher = hashlib.sha1()
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while True:
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data = filelike.read(HASH_READ_SIZE)
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if not data:
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break
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hasher.update(data)
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if hasattr(filelike, "seek"):
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# Reset the file handler to where it was before
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filelike.seek(file_pos)
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return hasher.hexdigest()
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