oracleobjectstorage: Use ChunkWriter Interfaces

[msays2000]

What is the purpose of this change?

Use the new ChunkWriter interfaces for multi part uploads introduced in #7154

Was the change discussed in an issue or in the forum before?

Yes, in #7154 and in #7056

Checklist

• I have read the contribution guidelines.
• I have added tests for all changes in this PR if appropriate.
• I have added documentation for the changes if appropriate.
• All commit messages are in house style.
• I'm done, this Pull Request is ready for review :-)

[msays2000]

@ncw I have used the new chunk writer interfaces as you have requested via #7154.
please review.

[ncw]

Just a couple of quick comments inline.

Can you rebase on the multithread2 branch please?

I had to change the ChunkWriter interface - it needed a ctx parameter on WriteChunk otherwise we can't cancel pending uploads properly.

I fixed the bug in multithread too but in a different way so you won't need the fs/operations/multithread.go fix.

Once you've rebased I'll give it a more thorough review.

Thank you.

[msays2000]

@ncw rebased with multithread2 branch. please review.

[ncw]

This looks very nice :-)

I put 2 minor points inline.

Do the integration tests all pass still?

Thank you :-)

[msays2000]

@ncw many tests are failing with hash type not supported .

// Hash returns the requested hash of the contents
func (i *StaticObjectInfo) Hash(ctx context.Context, h hash.Type) (string, error) {
	if len(i.hashes) == 0 {
		return "", hash.ErrUnsupported // this is the failure that is being returned. 
	}
	if hash, ok := i.hashes[h]; ok {
		return hash, nil
	}
	return "", hash.ErrUnsupported
}

=== RUN   TestRcat/withChecksum=true,ignoreChecksum=true
    run.go:180: Remote "oos:bucket rclone-test-jiyujuj8hujeqov0qiwixav0", Local "Local file system at /var/folders/c2/fxthjc2x34q0ztcr8h557h900000gn/T/rclone3100234066", Modify Window "1ms"
    operations_test.go:1740: 
        	Error Trace:	/Users/mkghosh/Code/rs/rclone/fs/operations/operations_test.go:1740
        	            				/Users/mkghosh/Code/rs/rclone/fs/operations/operations_test.go:1751
        	Error:      	Received unexpected error:
        	            	multipart upload failed to initialise: failed to prepare upload: hash type not supported
        	Test:       	TestRcat/withChecksum=true,ignoreChecksum=true

[msays2000]

found the problem fixed it, I had to return ui, nil rather than ui, err in prepare multipart upload

[ncw]

Let me know when you want me to take another look :-)

[msays2000]

@ncw please review again. all tests have passed. I have ignored a test case of uploading a stream of 0 length (i guess we are unable to determine its size prior to reading the stream) that results in multipart upload which doesn't accept empty list of parts to commit. A fix will be to fall back to PutObject for such empty stream later. Ok for now as I have seen it fail in TestS3 compatible way as well. Some other s3 providers have it in exception too.

[ncw]

Thank you this looks great now.

Don't worry about the 0 byte putstream this will never happen in practice as rclone buffers streams less than --streaming-upload-cutoff in memory and uploads then normally.

I'll merge this onto the multithread2 branch now and I'll merge that branch to master very soon.

Thank you :-)

[ncw]

I've merged this to master now - thank you :-)