github.com/dtroyer-salad/og2/v2@v2.0.0-20240412154159-c47231610877/internal/ioutil/io.go (about) 1 /* 2 Copyright The ORAS Authors. 3 Licensed under the Apache License, Version 2.0 (the "License"); 4 you may not use this file except in compliance with the License. 5 You may obtain a copy of the License at 6 7 http://www.apache.org/licenses/LICENSE-2.0 8 9 Unless required by applicable law or agreed to in writing, software 10 distributed under the License is distributed on an "AS IS" BASIS, 11 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 See the License for the specific language governing permissions and 13 limitations under the License. 14 */ 15 16 package ioutil 17 18 import ( 19 "errors" 20 "fmt" 21 "io" 22 "reflect" 23 "strconv" 24 25 ocispec "github.com/opencontainers/image-spec/specs-go/v1" 26 "oras.land/oras-go/v2/content" 27 "oras.land/oras-go/v2/internal/spec" 28 ) 29 30 // CloserFunc is the basic Close method defined in io.Closer. 31 type CloserFunc func() error 32 33 // Close performs close operation by the CloserFunc. 34 func (fn CloserFunc) Close() error { 35 return fn() 36 } 37 38 // CopyBuffer copies from src to dst through the provided buffer 39 // until either EOF is reached on src, or an error occurs. 40 // The copied content is verified against the size and the digest. 41 func CopyBuffer(dst io.Writer, src io.Reader, buf []byte, desc ocispec.Descriptor) error { 42 // verify while copying 43 ingestSize, _ := strconv.ParseInt(desc.Annotations[spec.AnnotationResumeOffset], 10, 64) 44 vr := content.NewVerifyReader(src, desc) 45 if n, err := io.CopyBuffer(dst, vr, buf); err != nil { 46 if errors.Is(err, io.ErrUnexpectedEOF) { 47 // Check if amount read == partial size 48 if n != (desc.Size - ingestSize) { 49 // sumthin's up 50 return fmt.Errorf("copy failed: %w", err) 51 } 52 } 53 } 54 return vr.Verify() 55 } 56 57 // Types returned by `io.NopCloser()`. 58 var ( 59 nopCloserType = reflect.TypeOf(io.NopCloser(nil)) 60 nopCloserWriterToType = reflect.TypeOf(io.NopCloser(struct { 61 io.Reader 62 io.WriterTo 63 }{})) 64 ) 65 66 // UnwrapNopCloser unwraps the reader wrapped by `io.NopCloser()`. 67 // Similar implementation can be found in the built-in package `net/http`. 68 // Reference: https://github.com/golang/go/blob/go1.22.1/src/net/http/transfer.go#L1090-L1105 69 func UnwrapNopCloser(r io.Reader) io.Reader { 70 switch reflect.TypeOf(r) { 71 case nopCloserType, nopCloserWriterToType: 72 return reflect.ValueOf(r).Field(0).Interface().(io.Reader) 73 default: 74 return r 75 } 76 }