[lestarch-autobot]

Related Issue(s)	#5249 — rebase/continuation of #5955 (original work by @bevinduckett, carried as co-author)
Has Unit Tests (y/n)	y (existing Os/test/ut suites exercise every service through the default delegate aliases; no new behaviour was added)
Documentation Included (y/n)	y (Os/docs/sdd.md, docs/how-to/integrate/implement-osal.md, default/config/OsSelection.hpp comments)
Generative AI was used in this contribution (y/n)	AI

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Change Description

Continuation of #5955 (@bevinduckett's branch, all of her commits preserved; devel merged in by the autobot and review follow-ups added on top — same merge-based flow the original branch used). It extends the compile-time alias mechanism introduced for Os::RawTime (#5617) and Os::Mutex/Os::ConditionVariable (#5936) to the remaining simple OSAL services: File, FileSystem, Directory, Console, CountingSemaphore, Cpu and Memory.

For each service, formulaically:

• Os/<Service>.hpp becomes a thin aggregator: includes Os/<Service>Interface.hpp, then #include OS_<SERVICE>_HEADER.
• The former wrapper class moves to Os/Delegate<Service>.{hpp,cpp} (link-time delegate, unchanged behaviour) and remains the default via using <Service> = Delegate<Service>;.
• Common non-virtual helpers (open(...) overloads, read(Fw::StringBase&), static singleton wrappers, etc.) move onto <Service>Interface so a direct alias inherits them.
• All aliases and OS_*_HEADER macros live in the consolidated default/config/OsSelection.hpp (Os: consolidate selection config headers into config/OsSelection.hpp #6049); the per-service config/OsDelegate<Service>.hpp headers from the original PR were dropped during the rebase.

Compatibility: a project config/OsSelection.hpp written before this PR (e.g. fprime-vorago's, which selects only RawTime/Mutex/ConditionVariable) defines neither the new aliases nor the OS_*_HEADER macros; each new aggregator falls back to the link-time delegate in that case instead of #error-ing, so existing overrides keep building. FW_FILE_HANDLE_MAX_SIZE is bumped 16 → 24 because FileInterface::m_mode pushes pointer-handle implementations (fprime-zephyr) past the old budget.

Rebase adaptations beyond the original PR: upstream's FileSystem::copyFile truncation fix (#6083) is carried into FileSystemInterface.cpp; the missing Os/ConsoleInterface.cpp referenced by Os/CMakeLists.txt was added; FW_DIRECTORY_HANDLE_MAX_SIZE is bumped 16 → 32 with a sizing comment (the open-state flag moved onto DirectoryInterface, originally part of #5955).

Migration note for projects that override PlatformCfg.fpp: FW_DIRECTORY_HANDLE_MAX_SIZE must be ≥ 24 (default now 32) and FW_FILE_HANDLE_MAX_SIZE ≥ 24 for pointer-handle File implementations (default now 24); the open state formerly held by the Os::File/Os::Directory wrappers now lives on the interface classes and is counted inside the handle budget. Companion pr-6318 branches on fprime-vorago-reference and fprime-zephyr-reference carry that bump for CI.

Rationale

Projects targeting bare-metal / small-RAM platforms (see #5249) can alias Os::File etc. directly to their implementation and avoid the delegate indirection and handle storage, while every existing build keeps the link-time delegate behaviour by default.

Testing/Review Recommendations

• CI is green with companion branches pr-6318 on fprime-community/fprime-vorago-reference and fprime-community/fprime-zephyr-reference (handle-size bumps; the Vorago one also pins Os/Baremetal/File: copy the FileInterface base in the copy constructor and operator= fprime-community/fprime-baremetal#60, a one-line FileInterface(other) copy-constructor fix). Merge those alongside this PR.

• fprime-util build, fprime-util build --ut + ctest (133/133 pass), TestDeploymentsProject/Ref build and Ref/test/int pytest suite against the GDS all pass on the rebased head; FileManager/PrmDb file operations exercised manually through the GDS.

• The change is large but repetitive; reviewing one service end-to-end (e.g. Os/File.hpp → Os/FileInterface.hpp → Os/DelegateFile.hpp/.cpp → OsSelection.hpp) and then diffing the pattern across the others is the quickest route.

• Behavioural note for reviewers: the virtual 3-argument open(path, mode, overwrite) is now both a public overload and the implementation hook; it applies no length bound (documented on FileInterface.hpp). The length/Fw::ConstStringBase overloads validate as before.

• An iterative local multi-agent review (security, correctness, supply-chain, design, operational-consequences, F´ C++ design, stale-documentation, architecture, test-quality, maintainability lenses) was run across three iterations; all must-fix findings were resolved. Residual acknowledged items are listed under Future Work.

Future Work

• A reusable CRC helper so a direct Os::File alias need not re-implement calculateCrc/incrementalCrc/finalizeCrc.
• static_assert(std::is_base_of<...>) in the aggregator headers to enforce the "MUST derive from the interface" rule at compile time.
• A separately-named virtual implementation hook for File::open so the public 3-argument overload could regain a path bound.
• No in-tree platform yet ships an alias-ready Console backend; in-tree tests cover only the default delegate aliases.

Contributor Checklist

• I have the rights to contribute this change set under the Apache-2.0 license.
• I agree to be bound by the contributor guidelines.

AI Usage (see policy)

AI (Devin, operated by @LeStarch) merged devel into #5955's branch, resolved the conflicts, adapted the PR to the consolidated config/OsSelection.hpp, fixed the build, ran the unit/integration/manual tests, and ran a local-only multi-agent review loop whose findings were triaged and fixed with minimal, repeated edits only. Original design and implementation by @bevinduckett.

• This contribution follows the F´ AI development skills (entered through AGENTS.md).

IAMAI

[github-actions]

Coverage report — base devel

Overall (line): 85.81% → 85.81% (+0.00)
Regression threshold: 0.50% (line).

Regressions

(none over threshold)

Modules changed

Module	Line	Δ	Function	Δ	Branch	Δ
Fw/DataStructures	97.51	-0.45	97.14	+0.00	81.93	-0.73
Os/Generic	90.18	-0.10	89.13	+0.00	75.10	-0.19
Os	20.14	+0.27	22.95	+0.37	17.49	+0.03
Os/Posix	71.08	+0.44	87.50	+0.00	51.11	+0.44
Svc/DpCatalog	89.44	+1.50	98.00	+0.13	82.44	+1.92
Svc/FprimeDeframer	100.00	+1.85	100.00	+0.00	100.00	+4.08

New modules

Module	Line	Function	Branch
Fw/Prm	0.00	0.00	0.00

Modules without UTs

CFDP/Checksum/GTest, Drv/LinuxGpioDriver, Drv/LinuxI2cDriver, Drv/LinuxSpiDriver, Drv/Ports/DataTypes, Drv/PosixUartDriver, FppTestProject/FppTest/topology/async, FppTestProject/FppTest/topology/components/Comp, FppTestProject/FppTest/topology/components/Framework, FppTestProject/FppTest/topology/components/Receiver, FppTestProject/FppTest/topology/components/Sender, FppTestProject/FppTest/topology/guarded, FppTestProject/FppTest/topology/sync, FppTestProject/FppTest/topology/top_ports, FppTestProject/FppTest/topology/types, Fw/Com, Fw/Comp, Fw/FilePacket/GTest, Fw/Fpy, Fw/Obj, Fw/Port, Fw/Sm, Fw/Test, Fw/Types/GTest, Os/Models, Svc/Ccsds/Types, Svc/Ccsds/Utils, Svc/FatalHandler, Svc/Subtopologies/CdhCore, Svc/Subtopologies/ComCcsds, Svc/Subtopologies/ComCcsdsSdls, Svc/Subtopologies/ComFprime, Svc/Subtopologies/ComLoggerTee, Svc/Subtopologies/DataProducts, Svc/Subtopologies/DpCompression, Svc/Subtopologies/FileHandling, Svc/Subtopologies/FileHandlingCfdp, Svc/Subtopologies/FileHandlingCfdp/FileHandlingCfdpConfig, TestDeploymentsProject/Ref/DpDemo, TestDeploymentsProject/Ref/PingReceiver, TestDeploymentsProject/Ref/RecvBuffApp, TestDeploymentsProject/Ref/SendBuffApp, TestDeploymentsProject/Ref/Top, TestDeploymentsProject/Ref/TypeDemo, cmake/test/data/TestConfigDeployment, cmake/test/data/TestDeployment/TestBuildAutocoder, cmake/test/data/TestDeployment/TestDuplicateDirective, cmake/test/data/TestDeployment/TestHeaderAutocoder, cmake/test/data/TestDeployment/TestLinkDepends, cmake/test/data/TestDeployment/TestRelative, cmake/test/data/test-fprime-library/TestLibrary/TestComponent, cmake/test/data/test-fprime-library2/TestLibrary2/TestComponent