-
-
Notifications
You must be signed in to change notification settings - Fork 7.5k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Replace the MD5 hashing of images with xxHash
Note that we only use this for change detection. The previous implementation invoked `MD5FromReaderFast` that created a MD5 has from 8 64 bytes chunks in the file, which is obviously very fast. The new implementation creates the hash from the entire file and ... seems to be even more effective: ``` name old time/op new time/op delta HashImage-10 9.45µs ±21% 10.89µs ± 1% ~ (p=0.343 n=4+4) name old alloc/op new alloc/op delta HashImage-10 144B ± 0% 8B ± 0% -94.44% (p=0.029 n=4+4) name old allocs/op new allocs/op delta HashImage-10 4.00 ± 0% 1.00 ± 0% -75.00% (p=0.029 n=4+4) ```
- Loading branch information
Showing
7 changed files
with
180 additions
and
29 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,86 @@ | ||
| // Copyright 2024 The Hugo Authors. All rights reserved. | ||
| // | ||
| // Licensed under the Apache License, Version 2.0 (the "License"); | ||
| // you may not use this file except in compliance with the License. | ||
| // You may obtain a copy of the License at | ||
| // http://www.apache.org/licenses/LICENSE-2.0 | ||
| // | ||
| // Unless required by applicable law or agreed to in writing, software | ||
| // distributed under the License is distributed on an "AS IS" BASIS, | ||
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| // See the License for the specific language governing permissions and | ||
| // limitations under the License. | ||
|
|
||
| // Package hashing provides common hashing utilities. | ||
| package hashing | ||
|
|
||
| import ( | ||
| "encoding/hex" | ||
| "io" | ||
| "sync" | ||
|
|
||
| "github.com/cespare/xxhash/v2" | ||
| ) | ||
|
|
||
| // XXHashFromReader calculates the xxHash for the given reader. | ||
| func XXHashFromReader(r io.ReadSeeker) (uint64, int64, error) { | ||
| h := getXxHashReadFrom() | ||
| defer putXxHashReadFrom(h) | ||
|
|
||
| size, err := io.Copy(h, r) | ||
| if err != nil { | ||
| return 0, 0, err | ||
| } | ||
| return h.Sum64(), size, nil | ||
| } | ||
|
|
||
| // XXHashFromString calculates the xxHash for the given string. | ||
| func XXHashFromString(s string) (uint64, error) { | ||
| h := xxhash.New() | ||
| h.WriteString(s) | ||
| return h.Sum64(), nil | ||
| } | ||
|
|
||
| // XxHashFromStringHexEncoded calculates the xxHash for the given string | ||
| // and returns the hash as a hex encoded string. | ||
| func XxHashFromStringHexEncoded(f string) string { | ||
| h := xxhash.New() | ||
| h.WriteString(f) | ||
| hash := h.Sum(nil) | ||
| return hex.EncodeToString(hash) | ||
| } | ||
|
|
||
| type xxhashReadFrom struct { | ||
| buff []byte | ||
| *xxhash.Digest | ||
| } | ||
|
|
||
| func (x *xxhashReadFrom) ReadFrom(r io.Reader) (int64, error) { | ||
| for { | ||
| n, err := r.Read(x.buff) | ||
| if n > 0 { | ||
| x.Digest.Write(x.buff[:n]) | ||
| } | ||
| if err != nil { | ||
| if err == io.EOF { | ||
| err = nil | ||
| } | ||
| return int64(n), err | ||
| } | ||
| } | ||
| } | ||
|
|
||
| var xXhashReadFromPool = sync.Pool{ | ||
| New: func() any { | ||
| return &xxhashReadFrom{Digest: xxhash.New(), buff: make([]byte, 48*1024)} | ||
| }, | ||
| } | ||
|
|
||
| func getXxHashReadFrom() *xxhashReadFrom { | ||
| return xXhashReadFromPool.Get().(*xxhashReadFrom) | ||
| } | ||
|
|
||
| func putXxHashReadFrom(h *xxhashReadFrom) { | ||
| h.Reset() | ||
| xXhashReadFromPool.Put(h) | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,79 @@ | ||
| // Copyright 2024 The Hugo Authors. All rights reserved. | ||
| // | ||
| // Licensed under the Apache License, Version 2.0 (the "License"); | ||
| // you may not use this file except in compliance with the License. | ||
| // You may obtain a copy of the License at | ||
| // http://www.apache.org/licenses/LICENSE-2.0 | ||
| // | ||
| // Unless required by applicable law or agreed to in writing, software | ||
| // distributed under the License is distributed on an "AS IS" BASIS, | ||
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| // See the License for the specific language governing permissions and | ||
| // limitations under the License. | ||
|
|
||
| package hashing | ||
|
|
||
| import ( | ||
| "strings" | ||
| "testing" | ||
|
|
||
| "github.com/cespare/xxhash/v2" | ||
| qt "github.com/frankban/quicktest" | ||
| ) | ||
|
|
||
| func TestXxHashFromReader(t *testing.T) { | ||
| c := qt.New(t) | ||
| s := "Hello World" | ||
| r := strings.NewReader(s) | ||
| got, size, err := XXHashFromReader(r) | ||
| c.Assert(err, qt.IsNil) | ||
| c.Assert(size, qt.Equals, int64(len(s))) | ||
| c.Assert(got, qt.Equals, uint64(7148569436472236994)) | ||
| } | ||
|
|
||
| func TestXxHashFromString(t *testing.T) { | ||
| c := qt.New(t) | ||
| s := "Hello World" | ||
| got, err := XXHashFromString(s) | ||
| c.Assert(err, qt.IsNil) | ||
| c.Assert(got, qt.Equals, uint64(7148569436472236994)) | ||
| } | ||
|
|
||
| func TestXxHashFromStringHexEncoded(t *testing.T) { | ||
| c := qt.New(t) | ||
| s := "The quick brown fox jumps over the lazy dog" | ||
| got := XxHashFromStringHexEncoded(s) | ||
| // Facit: https://asecuritysite.com/encryption/xxhash?val=The%20quick%20brown%20fox%20jumps%20over%20the%20lazy%20dog | ||
| c.Assert(got, qt.Equals, "0b242d361fda71bc") | ||
| } | ||
|
|
||
| func BenchmarkXXHashFromReader(b *testing.B) { | ||
| r := strings.NewReader("Hello World") | ||
| b.ResetTimer() | ||
| for i := 0; i < b.N; i++ { | ||
| XXHashFromReader(r) | ||
| r.Seek(0, 0) | ||
| } | ||
| } | ||
|
|
||
| func BenchmarkXXHashFromString(b *testing.B) { | ||
| s := "Hello World" | ||
| b.ResetTimer() | ||
| for i := 0; i < b.N; i++ { | ||
| XXHashFromString(s) | ||
| } | ||
| } | ||
|
|
||
| func BenchmarkXXHashFromStringHexEncoded(b *testing.B) { | ||
| s := "The quick brown fox jumps over the lazy dog" | ||
| b.ResetTimer() | ||
| for i := 0; i < b.N; i++ { | ||
| XxHashFromStringHexEncoded(s) | ||
| } | ||
| } | ||
|
|
||
| func xxHashFromString(f string) uint64 { | ||
| h := xxhash.New() | ||
| h.WriteString(f) | ||
| return h.Sum64() | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters