vbatts/registry
1
0
Fork 0
Code Issues Pull requests Releases Wiki Activity

Simplify digest.FromBytes calling convention

Browse source 
The current implementation of digest.FromBytes returns an error. This
error can never be non-nil, but its presence in the function signature
means each call site needs error handling code for an error that is
always nil.

I verified that none of the hash.Hash implementations in the standard
library can return an error on Write. Nor can any of the hash.Hash
implementations vendored in distribution.

This commit changes digest.FromBytes not to return an error. If Write
returns an error, it will panic, but as discussed above, this should
never happen.

This commit also avoids using a bytes.Reader to feed data into the hash
function in FromBytes. This makes the hypothetical case that would panic
a bit more explicit, and should also be more performant.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
This commit is contained in:
Aaron Lehmann 2015-12-14 14:30:51 -08:00
parent 23e4099973
commit 31047c8113
15 changed files with 31 additions and 78 deletions
Download patch file Download diff file Expand all files Collapse all files

16
digest/digest.go
View file

@ -1,7 +1,6 @@
package digest
import (
"bytes"
"fmt"
"hash"
"io"
@ -99,8 +98,19 @@ func FromTarArchive(rd io.Reader) (Digest, error) {
}
// FromBytes digests the input and returns a Digest.
func FromBytes(p []byte) (Digest, error) {
return FromReader(bytes.NewReader(p))
func FromBytes(p []byte) Digest {
digester := Canonical.New()
if _, err := digester.Hash().Write(p); err != nil {
// Writes to a Hash should never fail. None of the existing
// hash implementations in the stdlib or hashes vendored
// here can return errors from Write. Having a panic in this
// condition instead of having FromBytes return an error value
// avoids unnecessary error handling paths in all callers.
panic("write to hash function returned error: " + err.Error())
}
return digester.Digest()
}
// Validate checks that the contents of d is a valid digest, returning an