Action semantics and related improvements

[Anilm3]

• Parse action definitions in order to understand the semantics of each action, which means the WAF can now natively understand the difference between blocking actions (i.e. block, redirect) and other actions.
• Provide action definitions in ddwaf_result in map format, ensuring that only one blocking action (redirect > block) is provided. When two equivalent blocking actions are found, the first one takes precedence.
• Support stack_trace action and generate pseudo-uuidv4 during result serialisation.
• Add native support for monitor and extract_schema actions.
• Allow unknown actions for compatibility reasons.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 88.94231% with 23 lines in your changes are missing coverage. Please review.

Project coverage is 83.21%. Comparing base (24a89cb) to head (8ec7b52).

Files	Patch %	Lines
src/parser/actions_parser.cpp	85.00%	0 Missing and 6 partials ⚠️
src/event.cpp	93.33%	0 Missing and 5 partials ⚠️
src/parameter.cpp	64.28%	2 Missing and 3 partials ⚠️
src/action_mapper.cpp	91.17%	1 Missing and 2 partials ⚠️
src/ruleset_builder.cpp	78.57%	3 Missing ⚠️
src/parser/common.hpp	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #277      +/-   ##
==========================================
+ Coverage   83.09%   83.21%   +0.11%     
==========================================
  Files         115      119       +4     
  Lines        4566     4735     +169     
  Branches     2143     2253     +110     
==========================================
+ Hits         3794     3940     +146     
- Misses        300      304       +4     
- Partials      472      491      +19     

Flag	Coverage Δ
waf_test	83.21% <88.94%> (+0.11%)	⬆️

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[pr-commenter]

Benchmarks

Benchmark execution time: 2024-03-27 16:15:54

Comparing candidate commit d5a33d8 in PR branch anilm3/actions with baseline commit 24a89cb in branch master.

Found 3 performance improvements and 1 performance regressions! Performance is the same for 15 metrics, 0 unstable metrics.

scenario:regex_match_matcher.case_insensitive_flag.random

• 🟩 execution_time [-606.258µs; -604.775µs] or [-12.353%; -12.323%]

scenario:regex_match_matcher.case_insensitive_option.random

• 🟩 execution_time [-597.074µs; -595.476µs] or [-12.187%; -12.154%]

scenario:regex_match_matcher.lowercase_transformer.random

• 🟩 execution_time [-575.331µs; -574.451µs] or [-9.097%; -9.083%]

scenario:regex_match_matcher.random

• 🟥 execution_time [+63.963µs; +65.045µs] or [+3.305%; +3.361%]

[cataphract]

a bit of an aside, but I think it would be better at some point having a better (i.e, more efficient and expressive) for building ddwaf objects. Maybe something like this: https://github.com/DataDog/dd-trace-cpp/blob/60eed64ebbf89e85276d31f99f222d880ef88ae4/src/datadog/remote_config.cpp#L133-L152

[Anilm3]

Indeed, this is sorely needed, thanks for the tip.