Add ReadOnlyLoaded iterator for the DomainStorageMap

[janezpodhostnik]

Description

needed for: onflow/flow-go#8424

---

• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• Code follows the standards mentioned here
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[github-actions]

Benchstat comparison

• Base branch: onflow:master
• Base commit: fed5d1a

Results

	old.txt	new.txt
	time/op		delta
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ContractFunctionInvocation-4	402µs ± 0%	399µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
Emit-4	4.68ms ± 0%	4.60ms ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ExportType/composite_type-4	273ns ± 0%	280ns ± 0%	~	(p=1.000 n=1+1)
ExportType/simple_type-4	78.0ns ± 0%	77.8ns ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ImperativeFib-4	22.9µs ± 0%	23.1µs ± 0%	~	(p=1.000 n=1+1)
InterpretRecursionFib-4	2.28ms ± 0%	2.28ms ± 0%	~	(p=1.000 n=1+1)
NewInterpreter/new_interpreter-4	837ns ± 0%	842ns ± 0%	~	(p=1.000 n=1+1)
NewInterpreter/new_sub-interpreter-4	317ns ± 0%	317ns ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
RuntimeFungibleTokenTransferInterpreter-4	635µs ± 0%	630µs ± 0%	~	(p=1.000 n=1+1)
RuntimeFungibleTokenTransferVM-4	725µs ± 0%	729µs ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceDictionaryValues-4	2.64ms ± 0%	2.73ms ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceTracking-4	11.0ms ± 0%	11.6ms ± 0%	~	(p=1.000 n=1+1)
RuntimeScriptNoop-4	14.5µs ± 0%	14.8µs ± 0%	~	(p=1.000 n=1+1)
RuntimeVMInvokeContractImperativeFib-4	40.3µs ± 0%	40.8µs ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ValueIsSubtypeOfSemaType-4	62.9ns ± 0%	66.2ns ± 0%	~	(p=1.000 n=1+1)
	alloc/op		delta
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ContractFunctionInvocation-4	152kB ± 0%	152kB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
Emit-4	1.50MB ± 0%	1.50MB ± 0%	~	(p=1.000 n=1+1)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ExportType/composite_type-4	120B ± 0%	120B ± 0%	~	(all equal)
ExportType/simple_type-4	0.00B	0.00B	~	(all equal)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ImperativeFib-4	8.30kB ± 0%	8.30kB ± 0%	~	(all equal)
InterpretRecursionFib-4	1.19MB ± 0%	1.19MB ± 0%	~	(p=1.000 n=1+1)
NewInterpreter/new_interpreter-4	976B ± 0%	976B ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-4	232B ± 0%	232B ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
RuntimeFungibleTokenTransferInterpreter-4	171kB ± 0%	170kB ± 0%	~	(p=1.000 n=1+1)
RuntimeFungibleTokenTransferVM-4	193kB ± 0%	193kB ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceDictionaryValues-4	1.76MB ± 0%	1.77MB ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceTracking-4	8.59MB ± 0%	8.58MB ± 0%	~	(p=1.000 n=1+1)
RuntimeScriptNoop-4	8.06kB ± 0%	8.07kB ± 0%	~	(p=1.000 n=1+1)
RuntimeVMInvokeContractImperativeFib-4	13.3kB ± 0%	13.3kB ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ValueIsSubtypeOfSemaType-4	32.0B ± 0%	32.0B ± 0%	~	(all equal)
	allocs/op		delta
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ContractFunctionInvocation-4	2.47k ± 0%	2.47k ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
Emit-4	40.0k ± 0%	40.0k ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
ExportType/composite_type-4	3.00 ± 0%	3.00 ± 0%	~	(all equal)
ExportType/simple_type-4	0.00	0.00	~	(all equal)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ImperativeFib-4	176 ± 0%	176 ± 0%	~	(all equal)
InterpretRecursionFib-4	17.7k ± 0%	17.7k ± 0%	~	(all equal)
NewInterpreter/new_interpreter-4	15.0 ± 0%	15.0 ± 0%	~	(all equal)
NewInterpreter/new_sub-interpreter-4	4.00 ± 0%	4.00 ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/runtime goos:linux goarch:amd64
RuntimeFungibleTokenTransferInterpreter-4	3.27k ± 0%	3.27k ± 0%	~	(all equal)
RuntimeFungibleTokenTransferVM-4	3.73k ± 0%	3.73k ± 0%	~	(all equal)
RuntimeResourceDictionaryValues-4	36.7k ± 0%	36.8k ± 0%	~	(p=1.000 n=1+1)
RuntimeResourceTracking-4	144k ± 0%	144k ± 0%	~	(p=1.000 n=1+1)
RuntimeScriptNoop-4	114 ± 0%	114 ± 0%	~	(all equal)
RuntimeVMInvokeContractImperativeFib-4	424 ± 0%	424 ± 0%	~	(all equal)
pkg:github.com/onflow/cadence/interpreter goos:linux goarch:amd64
ValueIsSubtypeOfSemaType-4	1.00 ± 0%	1.00 ± 0%	~	(all equal)

[turbolent]

Great, thanks!

[fxamacker]

Yeah, I will move this to atree later after we confirm there is no additional changes to this needed by flow-go.

I opened this PR in Atree:

• Implement Iterator interfaces for LoadedValueIterator atree#635

Also opened a PR here to remove the wrapper and use the implementation in Atree:

• Replace mapLoadedValueIterator wrapper by using Atree implementation #4449