Clear/struct

[pawanrawal]

1. Clear out the struct given by user in Unmarshal. This is consistent with how json.Unmarshal behaves. This fixes error updating an edge value (delete/set) in same request #1216.
2. Also added helper functions to delete a Node and Edge from the client.

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This change is 

[ashwin95r]

Review status: 0 of 3 files reviewed at latest revision, 3 unresolved discussions.

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client/client.go, line 199 at r1 (raw file):

		e.nq.SubjectVar = n.String()
	} else {
		e.nq.Subject = n.String()

What if both Subject and SubjectVar are 0? what would we set for e.nq.Subject? We should make sure the node is valid before sending to server.

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client/unmarshal.go, line 216 at r1 (raw file):

	for i := 0; i < v.NumField(); i++ {
		f := v.Field(i)
		ft := t.Field(i)

Should we also check that this is accessible?

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client/unmarshal.go, line 222 at r1 (raw file):

		switch ft.Type.Kind() {
		case reflect.Slice:
			f.Set(reflect.MakeSlice(ft.Type, 0, 0))

Is there a way to just set it to [:0] instead of allocating again?
f.Slice(0, 0)
https://golang.org/pkg/reflect/#Value.Slice

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Comments from Reviewable

[janardhan1993]

Review status: 0 of 3 files reviewed at latest revision, 3 unresolved discussions.

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client/unmarshal.go, line 222 at r1 (raw file):

Previously, ashwin95r (Ashwin Ramesh) wrote…

Is there a way to just set it to [:0] instead of allocating again?
f.Slice(0, 0)
https://golang.org/pkg/reflect/#Value.Slice

https://github.com/golang/go/blob/master/src/encoding/json/decode.go#L578
Have a look at jon unmarshal, we need to handle other types like array

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Comments from Reviewable

[pawanrawal]

Review status: 0 of 9 files reviewed at latest revision, 3 unresolved discussions.

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client/client.go, line 199 at r1 (raw file):

Previously, ashwin95r (Ashwin Ramesh) wrote…

What if both Subject and SubjectVar are 0? what would we set for e.nq.Subject? We should make sure the node is valid before sending to server.

handling that in validate now.

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client/unmarshal.go, line 216 at r1 (raw file):

Previously, ashwin95r (Ashwin Ramesh) wrote…

Should we also check that this is accessible?

At this moment we are sure that v is of type struct and t is the type of struct so it should be ok to iterate over v.NumField and access t.Field(i)

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client/unmarshal.go, line 222 at r1 (raw file):

Previously, janardhan1993 (Janardhan Reddy) wrote…

https://github.com/golang/go/blob/master/src/encoding/json/decode.go#L578
Have a look at jon unmarshal, we need to handle other types like array

f.Slice doesn't work. JSON.Unmarshal also uses MakeSlice.
I don't think we need to support Array for now, I throw an error. They can just a slice. No one has asked for it too.

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Comments from Reviewable

[ashwin95r]

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Review status: 0 of 9 files reviewed at latest revision, 2 unresolved discussions.

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client/unmarshal.go, line 216 at r1 (raw file):

Previously, pawanrawal (Pawan Rawal) wrote…

At this moment we are sure that v is of type struct and t is the type of struct so it should be ok to iterate over v.NumField and access t.Field(i)

Why not just i < v.NumField() && i < t.NumField() ?

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Comments from Reviewable

[janardhan1993]

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Reviewed 9 of 9 files at r2.
Review status: all files reviewed at latest revision, 2 unresolved discussions.

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Comments from Reviewable

[pawanrawal]

Merged