[Improve]: use IReadOnlyStoreView instead.

[nan01ab]

Description

Using IReadOnlyStoreView instead of DataCache to make the semantics clearer in some read-only cases.

Fixes # (issue)

Type of change

• Optimization (the change is only an optimization)
• Style (the change is only a code style for better maintenance or standard purpose)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[Jim8y]

I think the name is still misleading,,, and confusing, storeview,,, snapshot,,,, datacache,,,,

[Jim8y]

I think the name is still misleading,,, and confusing, storeview,,, snapshot,,,, datacache,,,,

@shargon maybe you can have a pr to standardize the class/param names

[nan01ab]

I think the name is still misleading,,, and confusing, storeview,,, snapshot,,,, datacache,,,,

The name “StoreView” already exists, and no new things have been added.
If you have a better name, you can submit a pr

[cschuchardt88]

Just note that, Datacache should be removed. It is faster to get the data from leveldb database than with Datacache.

[nan01ab]

I think the name is still misleading,,, and confusing, storeview,,, snapshot,,,, datacache,,,,

@shargon maybe you can have a pr to standardize the class/param names

I think it's better to separate read-only APIs as an interface(for example, there are already IStore, IReadOnlyStore.).
And the interface name, do you have a better one? @Jim8y

[shargon]

Require testing to ensure that both types are detected by the native contract calls

[nan01ab]

I think the name is still misleading,,, and confusing, storeview,,, snapshot,,,, datacache,,,,

@Jim8y
Why add this interface?

1. Separating read-only APIs as an independent interface is a good practice (for example, there are already IStore and IReadOnlyStore.);

2. Most cases of using DataCache are read-only access, and the read-only interface makes these cases clearer;

3. On-chain data can only be modified by transaction execution.
   DataCache is also used by the p2p network and other modules, and these modules should access it in a read-only way.

4. The current caching mechanism is not working very well. The DataCache is often created and accessed only once and a key isn't accessed multiple times.