1 files changed, 81 insertions, 0 deletions
diff --git a/modules/packages/hashed_buffer.go b/modules/packages/hashed_buffer.go
new file mode 100644
index 0000000..4ab45ed
--- /dev/null
+++ b/modules/packages/hashed_buffer.go
@@ -0,0 +1,81 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package packages
+
+import (
+	"io"
+
+	"code.gitea.io/gitea/modules/util/filebuffer"
+)
+
+// HashedSizeReader provide methods to read, sum hashes and a Size method
+type HashedSizeReader interface {
+	io.Reader
+	HashSummer
+	Size() int64
+}
+
+// HashedBuffer is buffer which calculates multiple checksums
+type HashedBuffer struct {
+	*filebuffer.FileBackedBuffer
+
+	hash *MultiHasher
+
+	combinedWriter io.Writer
+}
+
+const DefaultMemorySize = 32 * 1024 * 1024
+
+// NewHashedBuffer creates a hashed buffer with the default memory size
+func NewHashedBuffer() (*HashedBuffer, error) {
+	return NewHashedBufferWithSize(DefaultMemorySize)
+}
+
+// NewHashedBufferWithSize creates a hashed buffer with a specific memory size
+func NewHashedBufferWithSize(maxMemorySize int) (*HashedBuffer, error) {
+	b, err := filebuffer.New(maxMemorySize)
+	if err != nil {
+		return nil, err
+	}
+
+	hash := NewMultiHasher()
+
+	combinedWriter := io.MultiWriter(b, hash)
+
+	return &HashedBuffer{
+		b,
+		hash,
+		combinedWriter,
+	}, nil
+}
+
+// CreateHashedBufferFromReader creates a hashed buffer with the default memory size and copies the provided reader data into it.
+func CreateHashedBufferFromReader(r io.Reader) (*HashedBuffer, error) {
+	return CreateHashedBufferFromReaderWithSize(r, DefaultMemorySize)
+}
+
+// CreateHashedBufferFromReaderWithSize creates a hashed buffer and copies the provided reader data into it.
+func CreateHashedBufferFromReaderWithSize(r io.Reader, maxMemorySize int) (*HashedBuffer, error) {
+	b, err := NewHashedBufferWithSize(maxMemorySize)
+	if err != nil {
+		return nil, err
+	}
+
+	_, err = io.Copy(b, r)
+	if err != nil {
+		return nil, err
+	}
+
+	return b, nil
+}
+
+// Write implements io.Writer
+func (b *HashedBuffer) Write(p []byte) (int, error) {
+	return b.combinedWriter.Write(p)
+}
+
+// Sums gets the MD5, SHA1, SHA256 and SHA512 checksums of the data
+func (b *HashedBuffer) Sums() (hashMD5, hashSHA1, hashSHA256, hashSHA512 []byte) {
+	return b.hash.Sums()
+}