Clean up the control flow of blobPipelineCompressionStep

Don't use else after each step that returns early.

The function nows looks like a set of ~special cases,
with the general fallback of doing nothing.

Signed-off-by: Miloslav Trmač <[email protected]>

copy/compression.go

@@ -115,7 +115,8 @@ func (c *copier) blobPipelineCompressionStep(stream *sourceStream, canModifyBlob
  uploadedCompressorName: uploadedAlgorithm.Name(),
  closers: closers,
  }, nil
- } else if canModifyBlob && c.dest.DesiredLayerCompression() == types.Compress && detected.isCompressed &&
+ }
+ if canModifyBlob && c.dest.DesiredLayerCompression() == types.Compress && detected.isCompressed &&
  c.compressionFormat != nil && c.compressionFormat.Name() != detected.format.Name() {
  // When the blob is compressed, but the desired format is different, it first needs to be decompressed and finally
  // re-compressed using the desired format.
@@ -147,7 +148,8 @@ func (c *copier) blobPipelineCompressionStep(stream *sourceStream, canModifyBlob
  uploadedCompressorName: c.compressionFormat.Name(),
  closers: closers,
  }, nil
- } else if canModifyBlob && c.dest.DesiredLayerCompression() == types.Decompress && detected.isCompressed {
+ }
+ if canModifyBlob && c.dest.DesiredLayerCompression() == types.Decompress && detected.isCompressed {
  logrus.Debugf("Blob will be decompressed")
  s, err := detected.decompressor(stream.reader)
  if err != nil {
@@ -167,28 +169,27 @@ func (c *copier) blobPipelineCompressionStep(stream *sourceStream, canModifyBlob
  uploadedCompressorName: internalblobinfocache.Uncompressed,
  closers: closers,
  }, nil
+ }
+ // PreserveOriginal might also need to recompress the original blob if the desired compression format is different.
+ logrus.Debugf("Using original blob without modification")
+ // Remember if the original blob was compressed, and if so how, so that if
+ // LayerInfosForCopy() returned something that differs from what was in the
+ // source's manifest, and UpdatedImage() needs to call UpdateLayerInfos(),
+ // it will be able to correctly derive the MediaType for the copied blob.
+ var algorithm *compressiontypes.Algorithm
+ if detected.isCompressed {
+ algorithm = &detected.format
  } else {
- // PreserveOriginal might also need to recompress the original blob if the desired compression format is different.
- logrus.Debugf("Using original blob without modification")
- // Remember if the original blob was compressed, and if so how, so that if
- // LayerInfosForCopy() returned something that differs from what was in the
- // source's manifest, and UpdatedImage() needs to call UpdateLayerInfos(),
- // it will be able to correctly derive the MediaType for the copied blob.
- var algorithm *compressiontypes.Algorithm
- if detected.isCompressed {
- algorithm = &detected.format
- } else {
- algorithm = nil
- }
- succeeded = true
- return &bpCompressionStepData{
- operation: types.PreserveOriginal,
- uploadedAlgorithm: algorithm,
- srcCompressorName: detected.srcCompressorName,
- uploadedCompressorName: detected.srcCompressorName,
- closers: closers,
- }, nil
+ algorithm = nil
  }
+ succeeded = true
+ return &bpCompressionStepData{
+ operation: types.PreserveOriginal,
+ uploadedAlgorithm: algorithm,
+ srcCompressorName: detected.srcCompressorName,
+ uploadedCompressorName: detected.srcCompressorName,
+ closers: closers,
+ }, nil
 }
 
 // updateCompressionEdits sets *operation, *algorithm and updates *annotations, if necessary.