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forgejo/modules/git/object_format.go
Lunny Xiao 4eb2a29910
Improve ObjectFormat interface (#28496)
The 4 functions are duplicated, especially as interface methods. I think
we just need to keep `MustID` the only one and remove other 3.

```
MustID(b []byte) ObjectID
MustIDFromString(s string) ObjectID
NewID(b []byte) (ObjectID, error)
NewIDFromString(s string) (ObjectID, error)
```

Introduced the new interfrace method `ComputeHash` which will replace
the interface `HasherInterface`. Now we don't need to keep two
interfaces.

Reintroduced `git.NewIDFromString` and `git.MustIDFromString`. The new
function will detect the hash length to decide which objectformat of it.
If it's 40, then it's SHA1. If it's 64, then it's SHA256. This will be
right if the commitID is a full one. So the parameter should be always a
full commit id.

@AdamMajer Please review.
2023-12-19 07:20:47 +00:00

93 lines
2.4 KiB
Go

// Copyright 2023 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package git
import (
"crypto/sha1"
"regexp"
"strconv"
)
// sha1Pattern can be used to determine if a string is an valid sha
var sha1Pattern = regexp.MustCompile(`^[0-9a-f]{4,40}$`)
type ObjectFormat interface {
// Name returns the name of the object format
Name() string
// EmptyObjectID creates a new empty ObjectID from an object format hash name
EmptyObjectID() ObjectID
// EmptyTree is the hash of an empty tree
EmptyTree() ObjectID
// FullLength is the length of the hash's hex string
FullLength() int
// IsValid returns true if the input is a valid hash
IsValid(input string) bool
// MustID creates a new ObjectID from a byte slice
MustID(b []byte) ObjectID
// ComputeHash compute the hash for a given ObjectType and content
ComputeHash(t ObjectType, content []byte) ObjectID
}
type Sha1ObjectFormatImpl struct{}
var (
emptyObjectID = &Sha1Hash{}
emptyTree = &Sha1Hash{
0x4b, 0x82, 0x5d, 0xc6, 0x42, 0xcb, 0x6e, 0xb9, 0xa0, 0x60,
0xe5, 0x4b, 0xf8, 0xd6, 0x92, 0x88, 0xfb, 0xee, 0x49, 0x04,
}
)
func (Sha1ObjectFormatImpl) Name() string { return "sha1" }
func (Sha1ObjectFormatImpl) EmptyObjectID() ObjectID {
return emptyObjectID
}
func (Sha1ObjectFormatImpl) EmptyTree() ObjectID {
return emptyTree
}
func (Sha1ObjectFormatImpl) FullLength() int { return 40 }
func (Sha1ObjectFormatImpl) IsValid(input string) bool {
return sha1Pattern.MatchString(input)
}
func (Sha1ObjectFormatImpl) MustID(b []byte) ObjectID {
var id Sha1Hash
copy(id[0:20], b)
return &id
}
// ComputeHash compute the hash for a given ObjectType and content
func (h Sha1ObjectFormatImpl) ComputeHash(t ObjectType, content []byte) ObjectID {
hasher := sha1.New()
_, _ = hasher.Write(t.Bytes())
_, _ = hasher.Write([]byte(" "))
_, _ = hasher.Write([]byte(strconv.FormatInt(int64(len(content)), 10)))
_, _ = hasher.Write([]byte{0})
// HashSum generates a SHA1 for the provided hash
var sha1 Sha1Hash
copy(sha1[:], hasher.Sum(nil))
return &sha1
}
var Sha1ObjectFormat ObjectFormat = Sha1ObjectFormatImpl{}
var SupportedObjectFormats = []ObjectFormat{
Sha1ObjectFormat,
// TODO: add sha256
}
func ObjectFormatFromName(name string) ObjectFormat {
for _, objectFormat := range SupportedObjectFormats {
if name == objectFormat.Name() {
return objectFormat
}
}
return nil
}
func IsValidObjectFormat(name string) bool {
return ObjectFormatFromName(name) != nil
}