Files
mfer/mfer/constants.go
T
clawbot 4bf87d1ccf
check / check (push) Failing after 2s
AddFileWithHash rejects hashes that are not multihashes (closes #129)
AddFileWithHash took any non-empty bytes as a hash, so the builder could
write a manifest that mfer refuses to load. It now decodes the hash with
go-multihash and also requires a digest of at least 32 bytes, the SHA-256
length the reader's decoding-cost limit assumes: a valid but shorter
multihash, such as an empty identity hash or SHA-1, still makes a
manifest of one-character paths too costly to load. When mfer freshen
meets such a hash in an existing manifest, its error names the manifest
entry and says to regenerate the manifest with mfer generate. Test
fixtures whose stand-in hashes were not valid multihashes now use a
SHA-256 multihash.

Model: opus-5-5
2026-10-04 14:48:49 +02:00

45 lines
1.5 KiB
Go

package mfer
const (
// Version is the current mfer release version.
Version = "0.1.0"
// ReleaseDate is the date on which Version was released.
ReleaseDate = "2025-12-17"
// MaxDecompressedSize is the maximum allowed size of decompressed manifest
// data (256 MB). This prevents decompression bombs from consuming excessive
// memory.
MaxDecompressedSize int64 = 256 * 1024 * 1024
// zstdWindowSize is the zstd window zstd.SpeedBestCompression gives mfer's writer.
zstdWindowSize = 8 << 20
// uuidLength is the length in bytes of a binary UUID.
uuidLength = 16
// Numbers in mf.proto of MFFile.files and of the MFFilePath fields
// that decoding sets aside a fixed amount of memory for.
filesFieldNumber = 101
hashesFieldNumber = 3
mimeTypeFieldNumber = 301
mtimeFieldNumber = 302
ctimeFieldNumber = 303
// Bytes decoding sets aside for each file entry, hash, timestamp and
// MIME type, however short its encoding. checkDecodedSize refuses an
// inner message for which these add up to more than maxDecodedGrowth
// times its size.
decodedFileEntrySize = 160
decodedHashSize = 112
decodedTimestampSize = 64
decodedMIMETypeSize = 16
// Each file entry mfer writes holds a path of at least one byte, a
// multihash at least as long as SHA-256's 34 bytes (AddFileWithHash
// refuses shorter ones) and a modification time: at least 47 bytes,
// counted at 336. So its manifests add up to at most about 7.15 times
// their size, and this limit is about 12% above that.
maxDecodedGrowth = 8
)