[C++][Improvement] Redesign and unify the implementation of validation in C++ Writer/Builder

[lixueclaire]

Proposed changes

We need to develop a more comprehensive and consistent approach to validation across all of GraphAr's tools and libraries. As the first step, this change redesigned and unified the implementation of validation for Writer and Builder in the C++ library.

• clarify and define different validation levels in the utils
• hide the Validate interface to users and use validate_level as a parameter of the writing operations
• simplify and unify the implementation for validation in Writer and Builder
• add a Clear() method to high-level Builder, enabling to add data and then dump for multiple rounds
• add test to prove the interface changes
• update C++ API Reference to include the ValidateLevel type

Types of changes

What types of changes does your code introduce to GraphAr?
Put an x in the boxes that apply

• Bugfix (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)
• Documentation Update (if none of the other choices apply)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• I have read the CONTRIBUTING doc
• I have signed the CLA
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

Solve #183

[github-actions]

🎊 PR Preview 6ac637a has been successfully built and deployed to https://alibaba-graphar-build-pr-186.surge.sh

_{🤖 By surge-preview}

[acezen]

Thanks for the job, it's overall look good to me. there are some places I think we can revise:

• In your design, the default_validate is invalid to writer/builder's validate level, so we need to note this in comment to users and add a check if validate_level is default_validate or not in constructors.
• It seems that weak/strong's check is different for different operations. Beside the brief doc for ValidateLevel, how about add some docs to the operations that what will weak and strong check for the operation? I think that would help develop and user to understand the operation's behavior.
• There are some codes not follow the google c++ code style, please fix them.

[lixueclaire]

Thanks for the job, it's overall look good to me. there are some places I think we can revise:

• In your design, the default_validate is invalid to writer/builder's validate level, so we need to note this in comment to users and add a check if validate_level is default_validate or not in constructors.
• It seems that weak/strong's check is different for different operations. Beside the brief doc for ValidateLevel, how about add some docs to the operations that what will weak and strong check for the operation? I think that would help develop and user to understand the operation's behavior.
• There are some codes not follow the google c++ code style, please fix them.

Thanks for your suggestions. For the second comment, weak/strong check is consistent for different operations now, strong_validate will also check the schema, while weak_validate only validates index, count, adj_list type, property group and size.

[acezen]

The code seems to meet the clang-format config, no need to refine.

[lixueclaire]

I have checked the validate_level passed to constructors; added comments in src to explain the implementations for validations added docstrings for different validate levels for each Writer/Builder; and fixed the code style. @acezen, could you please have a look again?

[acezen]

LGTM