Overview

This PR adds two new public entrypoints, ddwaf_context_multieval and ddwaf_subcontext_multieval, that evaluate multiple input batches in sequence within a single call and return one combined result. Functionally each entrypoint behaves like its _eval counterpart, except that data is an array of maps where every element is treated as a separate input batch and evaluated in order.

To support this, insertions to the object store now result in the batch being added to a queue, which then has to be explicitly applied before it's ready to be evaluated:

• insert_batch / insert_batches enqueue input (a single map, or an array of maps) without applying it.
• next_batch pops and applies the next queued batch, marking its targets as new.
• flush_input_queue drains any batches left unevaluated (e.g. after a timeout) on every exit path, applying them as "existing" targets targets so they carry over to subsequent calls and resets the new-target set for the next evaluation.

The evaluation engine now loops over batches, running pre-processors, filters, rules, and post-processors per batch, accumulating events/actions/attributes into the single result.

A new field has been added to the result object:

• evaluated: an unsigned integer reporting how many batches were fully evaluated. In the normal case this equals the number of non-empty batches; on timeout/error during batch i (0-based, counting non-empty batches) it equals I, i.e. the index of the batch where the problem occurred. Empty batches are skipped and don't count.

This field is present on the regular _eval results too (the result schema is shared), where it's simply 1 for a non-empty evaluated batch or 0 otherwise.

Files to review (src/)

• src/object_store.hpp / src/object_store.cpp: core change: the batch queue, insert_batch/insert_batches/insert_target/next_batch/flush_input_queue/enqueue_batch/apply_batch, and the insert_and_apply test helper. Worth the closest look for the queue lifetime and new-target semantics.
• src/evaluation_engine.cpp: the per-batch evaluation loop, flush_input_queue on exit, and the evaluated counter.
• src/evaluation_engine.hpp: insert_batch/insert_batches forwarding and the next_batch/insert_and_apply test internals.
• src/interface.cpp: the two new public functions plus the array-vs-map dispatch added to ddwaf_context_eval / ddwaf_subcontext_eval.
• src/context.hpp: context/subcontext forwarding for the new store methods and test internals.
• src/serializer.hpp / src/serializer.cpp: the evaluated field added to result_components and initialise_result_object.
• src/processor/base.hpp: processor output switched from insert to insert_target.