cuelabs.dev/go/oci/ociregistry@v0.0.0-20240906074133-82eb438dd565/ociunify/reader.go (about)

     1  // Copyright 2023 CUE Labs AG
     2  //
     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  package ociunify
    16  
    17  import (
    18  	"context"
    19  	"fmt"
    20  
    21  	"cuelabs.dev/go/oci/ociregistry"
    22  )
    23  
    24  // Reader methods.
    25  
    26  func (u unifier) GetBlob(ctx context.Context, repo string, digest ociregistry.Digest) (ociregistry.BlobReader, error) {
    27  	return runReadBlobReader(ctx, u, func(ctx context.Context, r ociregistry.Interface, i int) t2[ociregistry.BlobReader] {
    28  		return mk2(r.GetBlob(ctx, repo, digest))
    29  	})
    30  }
    31  
    32  func (u unifier) GetBlobRange(ctx context.Context, repo string, digest ociregistry.Digest, o0, o1 int64) (ociregistry.BlobReader, error) {
    33  	return runReadBlobReader(ctx, u,
    34  		func(ctx context.Context, r ociregistry.Interface, i int) t2[ociregistry.BlobReader] {
    35  			return mk2(r.GetBlobRange(ctx, repo, digest, o0, o1))
    36  		},
    37  	)
    38  }
    39  
    40  func (u unifier) GetManifest(ctx context.Context, repo string, digest ociregistry.Digest) (ociregistry.BlobReader, error) {
    41  	return runReadBlobReader(ctx, u,
    42  		func(ctx context.Context, r ociregistry.Interface, i int) t2[ociregistry.BlobReader] {
    43  			return mk2(r.GetManifest(ctx, repo, digest))
    44  		},
    45  	)
    46  }
    47  
    48  type blobReader struct {
    49  	ociregistry.BlobReader
    50  	cancel func()
    51  }
    52  
    53  func (r blobReader) Close() error {
    54  	defer r.cancel()
    55  	return r.BlobReader.Close()
    56  }
    57  
    58  func (u unifier) GetTag(ctx context.Context, repo string, tagName string) (ociregistry.BlobReader, error) {
    59  	r0, r1 := both(u, func(r ociregistry.Interface, _ int) t2[ociregistry.BlobReader] {
    60  		return mk2(r.GetTag(ctx, repo, tagName))
    61  	})
    62  	switch {
    63  	case r0.err == nil && r1.err == nil:
    64  		if r0.x.Descriptor().Digest == r1.x.Descriptor().Digest {
    65  			r1.x.Close()
    66  			return r0.get()
    67  		}
    68  		r0.close()
    69  		r1.close()
    70  		return nil, fmt.Errorf("conflicting results for tag")
    71  	case r0.err != nil && r1.err != nil:
    72  		return r0.get()
    73  	case r0.err == nil:
    74  		return r0.get()
    75  	case r1.err == nil:
    76  		return r1.get()
    77  	}
    78  	panic("unreachable")
    79  }
    80  
    81  func (u unifier) ResolveBlob(ctx context.Context, repo string, digest ociregistry.Digest) (ociregistry.Descriptor, error) {
    82  	return runRead(ctx, u, func(ctx context.Context, r ociregistry.Interface, _ int) t2[ociregistry.Descriptor] {
    83  		return mk2(r.ResolveBlob(ctx, repo, digest))
    84  	}).get()
    85  }
    86  
    87  func (u unifier) ResolveManifest(ctx context.Context, repo string, digest ociregistry.Digest) (ociregistry.Descriptor, error) {
    88  	return runRead(ctx, u, func(ctx context.Context, r ociregistry.Interface, _ int) t2[ociregistry.Descriptor] {
    89  		return mk2(r.ResolveManifest(ctx, repo, digest))
    90  	}).get()
    91  }
    92  
    93  func (u unifier) ResolveTag(ctx context.Context, repo string, tagName string) (ociregistry.Descriptor, error) {
    94  	r0, r1 := both(u, func(r ociregistry.Interface, _ int) t2[ociregistry.Descriptor] {
    95  		return mk2(r.ResolveTag(ctx, repo, tagName))
    96  	})
    97  	switch {
    98  	case r0.err == nil && r1.err == nil:
    99  		if r0.x.Digest == r1.x.Digest {
   100  			return r0.get()
   101  		}
   102  		return ociregistry.Descriptor{}, fmt.Errorf("conflicting results for tag")
   103  	case r0.err != nil && r1.err != nil:
   104  		return r0.get()
   105  	case r0.err == nil:
   106  		return r0.get()
   107  	case r1.err == nil:
   108  		return r1.get()
   109  	}
   110  	panic("unreachable")
   111  }
   112  
   113  func runReadBlobReader(ctx context.Context, u unifier, f func(ctx context.Context, r ociregistry.Interface, i int) t2[ociregistry.BlobReader]) (ociregistry.BlobReader, error) {
   114  	rv, cancel := runReadWithCancel(ctx, u, f)
   115  	r, err := rv.get()
   116  	if err != nil {
   117  		cancel()
   118  		return nil, err
   119  	}
   120  	return blobReader{
   121  		BlobReader: r,
   122  		cancel:     cancel,
   123  	}, nil
   124  }