MINIFICPP-2798 Mock library for C extensions

[martinzink]

Separates the CPP wrapper into a abstract interface and the Cffi layer (that commincates via the stable API), and also introduces a Mock alternative implementation, with its easier to create new unit tests that only test the processors controllers services business logic without the need to depend on the libminifi library.

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[Copilot]

Pull request overview

This PR introduces a C++ mock library intended to support testing/verification of C extensions, and refactors the C++ extension wrapper layer to rely on abstract ProcessContext / ProcessSession interfaces with concrete CFFI-backed implementations.

Changes:

• Refactor extension wrapper APIs (ProcessContext, ProcessSession, Logger) to use abstract base classes and CFFI-backed concrete implementations (Cffi*).
• Add a new mocklib (mock process context/session/logger + stubbed C API symbols) for extension testing without a full agent runtime.
• Extend/adjust C API utility helpers (minifiStringView, conversions) and add new small common utilities (regex wrapper + attribute error category).

Reviewed changes

Copilot reviewed 24 out of 28 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
libminifi/test/integration/extension-verification-test/CApiExtension.cpp	Updates extension metadata string-view helper usage.
extensions/llamacpp/processors/RunLlamaCppInference.cpp	Adjusts property access to updated ProcessContext API.
extensions/llamacpp/processors/ExtensionInitializer.cpp	Updates extension metadata string-view helper usage.
extension-framework/cpp-extension-lib/src/core/ProcessSession.cpp	Implements CFFI-backed ProcessSession operations + new session APIs.
extension-framework/cpp-extension-lib/src/core/ProcessContext.cpp	Implements CFFI-backed ProcessContext operations + dynamic props/SSL data.
extension-framework/cpp-extension-lib/src/core/logging/Logger.cpp	Renames/implements CFFI-backed logger wrapper.
extension-framework/cpp-extension-lib/src/core/ControllerServiceContext.cpp	Updates controller service property lookup string-view helper usage.
extension-framework/cpp-extension-lib/mocklib/src/MockProcessSession.cpp	Adds mock session implementation for tests (flow file lifecycle, content, attributes).
extension-framework/cpp-extension-lib/mocklib/src/MockProcessContext.cpp	Adds mock context implementation for tests (properties, defaults).
extension-framework/cpp-extension-lib/mocklib/src/mock-minifi-c.cpp	Adds stubbed C API symbol definitions for mock/test linkage.
extension-framework/cpp-extension-lib/mocklib/include/MockUtils.h	Adds small helpers for building mock processor metadata/logger.
extension-framework/cpp-extension-lib/mocklib/include/MockStreams.h	Adds in-memory mock InputStream/OutputStream implementations.
extension-framework/cpp-extension-lib/mocklib/include/MockProcessSession.h	Declares mock session class and mock flow file data model.
extension-framework/cpp-extension-lib/mocklib/include/MockProcessContext.h	Declares mock process context class.
extension-framework/cpp-extension-lib/mocklib/include/MockLogger.h	Adds a test logger capturing log strings by level.
extension-framework/cpp-extension-lib/mocklib/CMakeLists.txt	Adds build target for the new mock library.
extension-framework/cpp-extension-lib/include/api/utils/Ssl.h	Introduces SSL data structs for the extension API surface.
extension-framework/cpp-extension-lib/include/api/utils/ProcessorConfigUtils.h	Updates property parsing helpers to use the new getProperty(PropertyReference, FlowFile*) API.
extension-framework/cpp-extension-lib/include/api/utils/minifi-c-utils.h	Introduces minifiStringView + adds conversions from MinifiStringView.
extension-framework/cpp-extension-lib/include/api/core/Resource.h	Updates registration helpers to use CFFI wrappers + adds variadic registration helpers.
extension-framework/cpp-extension-lib/include/api/core/ProcessSession.h	Refactors ProcessSession into abstract interface + adds CffiProcessSession.
extension-framework/cpp-extension-lib/include/api/core/ProcessContext.h	Refactors ProcessContext into abstract interface + adds CffiProcessContext and new APIs.
extension-framework/cpp-extension-lib/include/api/core/logging/Logger.h	Renames wrapper to CffiLogger.
extension-framework/cpp-extension-lib/CMakeLists.txt	Adds mocklib subdirectory to build.
core-framework/common/src/utils/RegexUtils.cpp	Adds regex implementation backing new RegexUtils header.
core-framework/common/src/utils/AttributeErrors.cpp	Adds attribute error category implementation.
core-framework/common/include/utils/RegexUtils.h	Adds regex wrapper interface and libstdc++ workaround.
core-framework/common/include/utils/AttributeErrors.h	Adds attribute error code/category declarations.

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[lordgamez]

Great stuff 👍 LGTM just some minor nitpicks.

[fgerlits]

This looks like a copy of extension-framework/include/utils/net/Ssl.h. Can we remove the old file, or do we need both?

[szaszm]

we could remove this constructor and leave the struct to be an aggregate

Suggested change

	SslServerOptions(SslData cert_data, ClientAuthOption client_auth_option)
	: cert_data(cert_data),
	client_auth_option(client_auth_option) {}

[szaszm]

I'm guessing relationships are the key, I would add an inline comment to indicate that. Optionally you could also replace it with a Relationship object, the same one as session transfer takes

Suggested change

	std::map<std::string, std::vector<std::unique_ptr<MinifiFlowFile>>> transferred_flow_files_;
	std::map<std::string /* relationship name */, std::vector<std::unique_ptr<MinifiFlowFile>>> transferred_flow_files_;