feat: read libretro MAME's -rompath from ES-DE

ES-DE starts the libretro MAME core with a command line as its content
in 22 commands across 21 systems ("apple2e -rompath \"%GAMEDIRRAW%;
%ROMPATH%/apple2\" -flop1 ...", resources/systems/linux/es_systems.xml
at RetroDECK's 15e1b236 and EmuDeck's ES-DE v3.5.0), run through the
shell by popen (es-core/src/utils/PlatformUtil.cpp:231, 257).

At 5f5a0774 the core reads content that is no file as a command line
(retro_init.cpp:966-1008). Set_Path_Option passes its own -rompath
<content dir>;<system>/mame/bios;<system>/mame/roms (580-597), then
every word of the command line follows, -rompath included, only -rp
being dropped when mame_paths_enable is off (902-940, 914-919). MAME
keeps the later value of an option given twice at one priority
(src/lib/util/options.cpp:260-276, clifront.cpp:243). Those commands
read their sets in the folders they name, and mame/bios stays read by
every command that passes none.

The ES-DE parser records these commands in searched_by with their core,
the mame profile declares libretro_pools (-rompath and -rp stand for
mame/bios), and a set there also goes to each folder a command names
for a machine that reads it.

Manifests: EmuDeck gains 16 files below roms/ (apple2, apple2gs,
astrocde, crvision, gamate, gamecom, gmaster, intellivision, odyssey2,
scv, supracan, vectrex, videopac, vsmile). RetroDECK does not change:
its standalone MAME commands already put the same sets at the same
paths. No file leaves.

emulators/mame.yml

@@ -172,6 +172,14 @@ standalone_pools:
   pluginspath: "plugins"
   "-pluginspath": "plugins"
 
+libretro_pools:
+  "-rompath":
+    folder: "mame/bios"
+    source_ref: "src/osd/libretro/libretro-internal/retro_init.cpp:580-597, 804-809, 902-940, src/lib/util/options.cpp:260-276"
+  "-rp":
+    folder: "mame/bios"
+    source_ref: "src/osd/libretro/libretro-internal/retro_init.cpp:580-597, 804-809, 914-919"
+
 data_root:
   windows:
     path: "<working directory>"
@@ -195,7 +203,12 @@ notes: |
   samples, crosshair). ROM search: content_dir + system_dir/mame/bios +
   system_dir/mame/roms, never system_dir itself
   (src/osd/libretro/libretro-internal/retro_init.cpp:580-597), so the libretro
-  build reads its sets in mame/bios. Cheats via per-game XML files.
+  build reads its sets in mame/bios. Content that is no file is read as a
+  command line (retro_init.cpp:966-1008): a -rompath there is passed to
+  MAME after the core's own, and the later value wins
+  (src/lib/util/options.cpp:260-276), so the sets are read in the folders
+  it names. A -rp is dropped and appended to the core's list (580-597,
+  914-919). Cheats via per-game XML files.
   The standalone build splits every search path on semicolons and tries
   each directory in turn until the file opens (src/emu/fileio.cpp:53-58,
   330-392). rompath defaults to roms, samplepath to samples, hashpath to

platforms/romfolders/emudeck-windows.yml

@@ -222,6 +222,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:128"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - apple2
+    machines:
+    - apple2e
+    source_ref: "esde resources/systems/windows/es_systems.xml:135"
   - emulator: mame
     reads:
     - apple2
@@ -237,6 +244,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:142"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - apple2gs
+    machines:
+    - apple2gs
+    source_ref: "esde resources/systems/windows/es_systems.xml:146,147"
   - emulator: mame
     reads:
     - apple2gs
@@ -279,6 +293,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:191"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - arcadia
+    machines:
+    - arcadia
+    source_ref: "esde resources/systems/windows/es_systems.xml:196"
   - emulator: mame
     reads:
     - arcadia
@@ -348,6 +369,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:225"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - astrocde
+    machines:
+    - astrocde
+    source_ref: "esde resources/systems/windows/es_systems.xml:229"
   - emulator: mame
     reads:
     - astrocde
@@ -391,6 +419,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:262"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - atari7800
+    machines:
+    - a7800
+    source_ref: "esde resources/systems/windows/es_systems.xml:267"
   - emulator: mame
     reads:
     - atari7800
@@ -624,6 +659,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:411"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - channelf
+    machines:
+    - channelf
+    source_ref: "esde resources/systems/windows/es_systems.xml:416"
   - emulator: mame
     reads:
     - channelf
@@ -748,6 +790,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:553"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - crvision
+    machines:
+    - crvision
+    source_ref: "esde resources/systems/windows/es_systems.xml:558"
   - emulator: mame
     reads:
     - crvision
@@ -988,6 +1037,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:769"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - fmtowns
+    machines:
+    - fmtownshr
+    source_ref: "esde resources/systems/windows/es_systems.xml:773"
   - emulator: mame
     reads:
     - fmtowns
@@ -1009,6 +1065,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:790"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - gamate
+    machines:
+    - gamate
+    source_ref: "esde resources/systems/windows/es_systems.xml:794"
   - emulator: mame
     reads:
     - gamate
@@ -1038,6 +1101,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:812"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - gamecom
+    machines:
+    - gamecom
+    source_ref: "esde resources/systems/windows/es_systems.xml:816"
   - emulator: mame
     reads:
     - gamecom
@@ -1169,6 +1239,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:954"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - gmaster
+    machines:
+    - gmaster
+    source_ref: "esde resources/systems/windows/es_systems.xml:958"
   - emulator: mame
     reads:
     - gmaster
@@ -1210,6 +1287,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:975"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - intellivision
+    machines:
+    - intv
+    source_ref: "esde resources/systems/windows/es_systems.xml:980"
   - emulator: mame
     reads:
     - intellivision
@@ -1479,6 +1563,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:1227"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - megaduck
+    machines:
+    - megaduck
+    source_ref: "esde resources/systems/windows/es_systems.xml:1232"
   - emulator: mame
     reads:
     - megaduck
@@ -1834,6 +1925,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:1548"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - odyssey2
+    machines:
+    - odyssey2
+    source_ref: "esde resources/systems/windows/es_systems.xml:1553"
   - emulator: mame
     reads:
     - odyssey2
@@ -2136,6 +2234,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:1798"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - pv1000
+    machines:
+    - pv1000
+    source_ref: "esde resources/systems/windows/es_systems.xml:1802"
   - emulator: mame
     reads:
     - pv1000
@@ -2223,6 +2328,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:1898"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - scv
+    machines:
+    - scv
+    source_ref: "esde resources/systems/windows/es_systems.xml:1902"
   - emulator: mame
     reads:
     - scv
@@ -2479,6 +2591,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:2138"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - supervision
+    machines:
+    - svision
+    source_ref: "esde resources/systems/windows/es_systems.xml:2143"
   - emulator: mame
     reads:
     - supervision
@@ -2494,6 +2613,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:2149"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - supracan
+    machines:
+    - supracan
+    source_ref: "esde resources/systems/windows/es_systems.xml:2153"
   - emulator: mame
     reads:
     - supracan
@@ -2659,6 +2785,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:2296"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - vectrex
+    machines:
+    - vectrex
+    source_ref: "esde resources/systems/windows/es_systems.xml:2301"
   - emulator: mame
     reads:
     - vectrex
@@ -2714,6 +2847,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:2317"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - videopac
+    machines:
+    - videopac
+    source_ref: "esde resources/systems/windows/es_systems.xml:2322"
   - emulator: mame
     reads:
     - videopac
@@ -2754,6 +2894,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/windows/es_systems.xml:2357"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - vsmile
+    machines:
+    - vsmile
+    source_ref: "esde resources/systems/windows/es_systems.xml:2361"
   - emulator: mame
     reads:
     - vsmile

platforms/romfolders/emudeck.yml

@@ -221,6 +221,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:131"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - apple2
+    machines:
+    - apple2e
+    source_ref: "esde resources/systems/linux/es_systems.xml:138"
   - emulator: mame
     reads:
     - apple2
@@ -236,6 +243,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:145"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - apple2gs
+    machines:
+    - apple2gs
+    source_ref: "esde resources/systems/linux/es_systems.xml:149,150"
   - emulator: mame
     reads:
     - apple2gs
@@ -278,6 +292,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:193"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - arcadia
+    machines:
+    - arcadia
+    source_ref: "esde resources/systems/linux/es_systems.xml:198"
   - emulator: mame
     reads:
     - arcadia
@@ -347,6 +368,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:226"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - astrocde
+    machines:
+    - astrocde
+    source_ref: "esde resources/systems/linux/es_systems.xml:230"
   - emulator: mame
     reads:
     - astrocde
@@ -390,6 +418,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:263"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - atari7800
+    machines:
+    - a7800
+    source_ref: "esde resources/systems/linux/es_systems.xml:268"
   - emulator: mame
     reads:
     - atari7800
@@ -619,6 +654,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:412"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - channelf
+    machines:
+    - channelf
+    source_ref: "esde resources/systems/linux/es_systems.xml:417"
   - emulator: mame
     reads:
     - channelf
@@ -743,6 +785,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:552"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - crvision
+    machines:
+    - crvision
+    source_ref: "esde resources/systems/linux/es_systems.xml:557"
   - emulator: mame
     reads:
     - crvision
@@ -984,6 +1033,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:776"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - fmtowns
+    machines:
+    - fmtownshr
+    source_ref: "esde resources/systems/linux/es_systems.xml:780"
   - emulator: mame
     reads:
     - fmtowns
@@ -1003,6 +1059,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:796"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - gamate
+    machines:
+    - gamate
+    source_ref: "esde resources/systems/linux/es_systems.xml:800"
   - emulator: mame
     reads:
     - gamate
@@ -1032,6 +1095,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:818"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - gamecom
+    machines:
+    - gamecom
+    source_ref: "esde resources/systems/linux/es_systems.xml:822"
   - emulator: mame
     reads:
     - gamecom
@@ -1163,6 +1233,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:962"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - gmaster
+    machines:
+    - gmaster
+    source_ref: "esde resources/systems/linux/es_systems.xml:966"
   - emulator: mame
     reads:
     - gmaster
@@ -1204,6 +1281,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:983"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - intellivision
+    machines:
+    - intv
+    source_ref: "esde resources/systems/linux/es_systems.xml:988"
   - emulator: mame
     reads:
     - intellivision
@@ -1475,6 +1559,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:1233"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - megaduck
+    machines:
+    - megaduck
+    source_ref: "esde resources/systems/linux/es_systems.xml:1238"
   - emulator: mame
     reads:
     - megaduck
@@ -1823,6 +1914,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:1558"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - odyssey2
+    machines:
+    - odyssey2
+    source_ref: "esde resources/systems/linux/es_systems.xml:1563"
   - emulator: mame
     reads:
     - odyssey2
@@ -2122,6 +2220,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:1814"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - pv1000
+    machines:
+    - pv1000
+    source_ref: "esde resources/systems/linux/es_systems.xml:1818"
   - emulator: mame
     reads:
     - pv1000
@@ -2209,6 +2314,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:1910"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - scv
+    machines:
+    - scv
+    source_ref: "esde resources/systems/linux/es_systems.xml:1914"
   - emulator: mame
     reads:
     - scv
@@ -2464,6 +2576,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:2150"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - supervision
+    machines:
+    - svision
+    source_ref: "esde resources/systems/linux/es_systems.xml:2155"
   - emulator: mame
     reads:
     - supervision
@@ -2479,6 +2598,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:2161"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - supracan
+    machines:
+    - supracan
+    source_ref: "esde resources/systems/linux/es_systems.xml:2165"
   - emulator: mame
     reads:
     - supracan
@@ -2646,6 +2772,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:2311"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - vectrex
+    machines:
+    - vectrex
+    source_ref: "esde resources/systems/linux/es_systems.xml:2316"
   - emulator: mame
     reads:
     - vectrex
@@ -2701,6 +2834,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:2332"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - videopac
+    machines:
+    - videopac
+    source_ref: "esde resources/systems/linux/es_systems.xml:2337"
   - emulator: mame
     reads:
     - videopac
@@ -2741,6 +2881,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:2372"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - vsmile
+    machines:
+    - vsmile
+    source_ref: "esde resources/systems/linux/es_systems.xml:2376"
   - emulator: mame
     reads:
     - vsmile

platforms/romfolders/retrodeck.yml

@@ -195,6 +195,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:139"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - apple2
+    machines:
+    - apple2e
+    source_ref: "esde resources/systems/linux/es_systems.xml:146"
   - emulator: mame
     reads:
     - apple2
@@ -210,6 +217,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:153"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - apple2gs
+    machines:
+    - apple2gs
+    source_ref: "esde resources/systems/linux/es_systems.xml:157"
   - emulator: mame
     reads:
     - apple2gs
@@ -247,6 +261,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:198"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - arcadia
+    machines:
+    - arcadia
+    source_ref: "esde resources/systems/linux/es_systems.xml:203"
   - emulator: mame
     reads:
     - arcadia
@@ -316,6 +337,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:231"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - astrocde
+    machines:
+    - astrocde
+    source_ref: "esde resources/systems/linux/es_systems.xml:235"
   - emulator: mame
     reads:
     - astrocde
@@ -358,6 +386,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:268"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - atari7800
+    machines:
+    - a7800
+    source_ref: "esde resources/systems/linux/es_systems.xml:273"
   - emulator: mame
     reads:
     - atari7800
@@ -570,6 +605,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:420"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - channelf
+    machines:
+    - channelf
+    source_ref: "esde resources/systems/linux/es_systems.xml:425"
   - emulator: mame
     reads:
     - channelf
@@ -694,6 +736,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:557"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - crvision
+    machines:
+    - crvision
+    source_ref: "esde resources/systems/linux/es_systems.xml:562"
   - emulator: mame
     reads:
     - crvision
@@ -921,6 +970,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:785"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - fmtowns
+    machines:
+    - fmtownshr
+    source_ref: "esde resources/systems/linux/es_systems.xml:789"
   - emulator: mame
     reads:
     - fmtowns
@@ -936,6 +992,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:807"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - gamate
+    machines:
+    - gamate
+    source_ref: "esde resources/systems/linux/es_systems.xml:811"
   - emulator: mame
     reads:
     - gamate
@@ -965,6 +1028,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:829"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - gamecom
+    machines:
+    - gamecom
+    source_ref: "esde resources/systems/linux/es_systems.xml:833"
   - emulator: mame
     reads:
     - gamecom
@@ -1096,6 +1166,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:972"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - gmaster
+    machines:
+    - gmaster
+    source_ref: "esde resources/systems/linux/es_systems.xml:976"
   - emulator: mame
     reads:
     - gmaster
@@ -1137,6 +1214,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:993"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - intellivision
+    machines:
+    - intv
+    source_ref: "esde resources/systems/linux/es_systems.xml:998"
   - emulator: mame
     reads:
     - intellivision
@@ -1381,6 +1465,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:1247"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - megaduck
+    machines:
+    - megaduck
+    source_ref: "esde resources/systems/linux/es_systems.xml:1252"
   - emulator: mame
     reads:
     - megaduck
@@ -1718,6 +1809,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:1576"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - odyssey2
+    machines:
+    - odyssey2
+    source_ref: "esde resources/systems/linux/es_systems.xml:1581"
   - emulator: mame
     reads:
     - odyssey2
@@ -2028,6 +2126,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:1854"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - pv1000
+    machines:
+    - pv1000
+    source_ref: "esde resources/systems/linux/es_systems.xml:1858"
   - emulator: mame
     reads:
     - pv1000
@@ -2104,6 +2209,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:1951"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - scv
+    machines:
+    - scv
+    source_ref: "esde resources/systems/linux/es_systems.xml:1955"
   - emulator: mame
     reads:
     - scv
@@ -2352,6 +2464,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:2193"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - supervision
+    machines:
+    - svision
+    source_ref: "esde resources/systems/linux/es_systems.xml:2198"
   - emulator: mame
     reads:
     - supervision
@@ -2367,6 +2486,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:2204"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - supracan
+    machines:
+    - supracan
+    source_ref: "esde resources/systems/linux/es_systems.xml:2208"
   - emulator: mame
     reads:
     - supracan
@@ -2509,6 +2635,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:2357"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - vectrex
+    machines:
+    - vectrex
+    source_ref: "esde resources/systems/linux/es_systems.xml:2362"
   - emulator: mame
     reads:
     - vectrex
@@ -2564,6 +2697,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:2378"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - videopac
+    machines:
+    - videopac
+    source_ref: "esde resources/systems/linux/es_systems.xml:2383"
   - emulator: mame
     reads:
     - videopac
@@ -2597,6 +2737,13 @@ folders:
   emulator: retroarch
   source_ref: "esde resources/systems/linux/es_systems.xml:2420"
   searched_by:
+  - emulator: retroarch
+    core: mame
+    reads:
+    - vsmile
+    machines:
+    - vsmile
+    source_ref: "esde resources/systems/linux/es_systems.xml:2424"
   - emulator: mame
     reads:
     - vsmile

schemas/emulator.schema.json

@@ -1112,6 +1112,24 @@
       },
       "description": "Settings the standalone build reads as a list of directories it searches one after the other, each mapped to the subfolder of the layout (relative to standalone_directories, empty for the whole of it) its directories stand for: openMSX's filepool entries are searched like share/systemroms, XRoar's rompath entries hold the ROMs themselves. A file in any entry is read, so several platform records naming entries give the first one a pack can fill."
     },
+    "libretro_pools": {
+      "type": "object",
+      "additionalProperties": {
+        "oneOf": [
+          {"type": "string"},
+          {
+            "type": "object",
+            "additionalProperties": false,
+            "required": ["folder", "source_ref"],
+            "properties": {
+              "folder": {"type": "string"},
+              "source_ref": {"type": "string", "minLength": 1, "description": "Where the build reads the option from its content"}
+            }
+          }
+        ]
+      },
+      "description": "Options of the command line a libretro build is handed as its content that set a list of directories it searches, each mapped to the folder below the system directory whose files those directories stand for: libretro MAME hands MAME <system>/mame/bios unless the content's own -rompath replaces it."
+    },
     "prose_written_at": {
       "type": "string",
       "pattern": "^[0-9a-f]{40}$",

schemas/romfolders.schema.json

@@ -123,13 +123,14 @@
           "arcade": { "type": "boolean" },
           "searched_by": {
             "type": "array",
-            "description": "The standalone emulators whose commands for this folder pass a ROM search path, and the folders below the roms root it names.",
+            "description": "The emulators, or the libretro core with its runner, whose commands for this folder pass a ROM search path, and the folders below the roms root it names.",
             "items": {
               "type": "object",
               "additionalProperties": false,
               "required": ["emulator", "reads", "source_ref"],
               "properties": {
                 "emulator": { "type": "string", "minLength": 1 },
+                "core": { "type": "string", "minLength": 1, "description": "The libretro core RetroArch starts, handed the search path in its content command line." },
                 "reads": { "type": "array", "minItems": 1, "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
                 "machines": { "type": "array", "description": "The machines the commands start, as the emulator names them.", "items": { "type": "string", "minLength": 1 }, "uniqueItems": true },
                 "any_machine": { "type": "boolean", "description": "A command starts the game itself as the machine (ES-DE's %BASENAME%)." },

scripts/common.py

@@ -2872,9 +2872,10 @@ CONTENT_SCOPE_TAG = "contentscope:"
 # [core name, roms folder, (tree, path)]: a libretro core the platform
 # launches for the games of that folder, which it reads beside.
 CONTENT_FOLDER_PREFIX = "contentdir:"
-# [emulator, (tree, path), system, machines, any machine, source_ref]: a
+# [emulator or core, (tree, path), system, machines, any machine,
-# standalone emulator handed a roms folder as its ROM search path on the
+# source_ref, build]: a standalone emulator, or a libretro core in the
-# command line of a system's launch.
+# command line it is handed as content, given a roms folder as its ROM
+# search path by a system's launch command.
 ROM_SEARCH_PREFIX = "romsearch:"
 # The frontend writes the BIOS it hands a core beside the content: the
 # folder it gives the BIOS is the content's.
@@ -3413,7 +3414,7 @@ def _core_key(name: str) -> str:
 
 def content_folder_tags(config: dict) -> set[str]:
     """The roms folders a platform launches each libretro core for, and the
-    ROM search paths its commands hand standalone emulators, as tags.
+    ROM search paths its commands hand emulators and cores, as tags.
 
     A core reading its BIOS sets beside the game (MAME 2003's osd_get_path
     gives FILETYPE_ROM the content directory) reads them in the folder of
@@ -3466,9 +3467,10 @@ def content_folder_tags(config: dict) -> set[str]:
             for read in search.get("reads") or []:
                 if read in folders:
                     tags.add(ROM_SEARCH_PREFIX + json.dumps([
-                        str(search["emulator"]), place(read), str(row["folder"]),
+                        str(search.get("core") or search["emulator"]), place(read),
-                        sorted(search.get("machines") or []), bool(search.get("any_machine")),
+                        str(row["folder"]), sorted(search.get("machines") or []),
-                        str(search.get("source_ref", "")),
+                        bool(search.get("any_machine")), str(search.get("source_ref", "")),
+                        "libretro" if search.get("core") else "standalone",
                     ]))
     return tags
 
@@ -3550,10 +3552,11 @@ def content_layout(
 
     A libretro entry read beside the content (``load_from: content_dir``)
     goes to the folder of each system the platform launches the core for,
-    and is named as read outside the BIOS folder where it knows none. A
+    and is named as read outside the BIOS folder where it knows none. An
-    standalone entry no launcher record places, under the root of the
+    entry in the folder a passed ROM search path stands for (the root of a
-    layout a passed ROM search path stands for, goes to each folder a
+    standalone layout no launcher record places it in, a ``libretro_pools``
-    command passes for a machine that reads it. Outside a platform (no
+    folder) goes to each folder a command passes for a machine that reads
+    it, a libretro one staying where it is too. Outside a platform (no
     CONTENT_SCOPE_TAG) the view is left as it is.
     """
     tags = [t for t in standalone_cores if t.startswith(CONTENT_TAG_PREFIXES)]
@@ -3571,6 +3574,29 @@ def content_layout(
     files = view.get("files") or []
     out: list = []
     changed = False
+    searches = [
+        json.loads(t[len(ROM_SEARCH_PREFIX):])
+        for t in tags if t.startswith(ROM_SEARCH_PREFIX)
+    ]
+    build = "standalone" if standalone else "libretro"
+    searches = [s for s in searches if _core_key(s[0]) in names and s[6] == build]
+
+    def search_reads(name: str) -> list[tuple[str, str]]:
+        stem = name.rsplit(".", 1)[0]
+        return sorted({
+            tuple(where) for _emu, where, system, machines, any_machine, _ref, _build in searches
+            if where and stem in rom_search_sets(emu_name, system, machines, any_machine)
+        })
+
+    def roms_entry(entry: dict, tree: str, folder: str, rel: str) -> dict:
+        # Below the roms root inside the install tree (EmuELEC's
+        # /storage/roms): a plain dest the platform prefix skips, as a
+        # standalone entry placed there (_placed_entry).
+        where: dict[str, object] = (
+            {"unprefixed": True} if tree == "install" else {"root": ROMS_ROOT}
+        )
+        return {**entry, **where, "path": f"{folder}/{rel}", "layout_path": rel}
+
     if not standalone:
         folders = sorted({
             tuple(where) for core, _folder, where in (
@@ -3578,11 +3604,25 @@ def content_layout(
                 for t in tags if t.startswith(CONTENT_FOLDER_PREFIX)
             ) if core in names and where
         })
+        # The folders a passed -rompath replaces the build's own search
+        # path with stand for these: libretro MAME hands MAME
+        # <system>/mame/bios unless the content's command line names
+        # another (retro_init.cpp Set_Path_Option, execute_game_cmd).
+        from launchers import pool_folders  # noqa: PLC0415
+
+        pools = set(pool_folders({"standalone_pools": view.get("libretro_pools")}).values())
         for f in files:
-            if (not isinstance(f, dict) or _content_load(f) != "content_dir"
+            if not isinstance(f, dict):
-                    or f.get("category") == "game_data"):
+                out.append(f)
+                continue
+            if _content_load(f) != "content_dir" or f.get("category") == "game_data":
                 # Game data read beside the content is the game's own.
                 out.append(f)
+                parent, _, rel = str(f.get("path") or "").rpartition("/")
+                if searches and parent in pools and rel:
+                    reads = search_reads(rel)
+                    changed |= bool(reads)
+                    out.extend(roms_entry(f, tree, folder, rel) for tree, folder in reads)
                 continue
             changed = True
             plain = _without_libretro_load(f)
@@ -3590,20 +3630,8 @@ def content_layout(
                 out.append({**plain, "unplaced": OUTSIDE_BIOS_FOLDER})
                 continue
             rel = str(f.get("path") or f.get("name") or "")
-            for tree, folder in folders:
+            out.extend(roms_entry(plain, tree, folder, rel) for tree, folder in folders)
-                # Below the roms root inside the install tree (EmuELEC's
-                # /storage/roms): a plain dest the platform prefix skips, as
-                # a standalone entry placed there (_placed_entry).
-                where: dict[str, object] = (
-                    {"unprefixed": True} if tree == "install" else {"root": ROMS_ROOT}
-                )
-                out.append({**plain, **where, "path": f"{folder}/{rel}", "layout_path": rel})
         return {**view, "files": out} if changed else view
-    searches = [
-        json.loads(t[len(ROM_SEARCH_PREFIX):])
-        for t in tags if t.startswith(ROM_SEARCH_PREFIX)
-    ]
-    searches = [s for s in searches if _core_key(s[0]) in names]
     pools = {str(v).strip("/") for v in (view.get("standalone_pools") or {}).values()}
     if not searches or "" not in pools:
         return view
@@ -3612,11 +3640,7 @@ def content_layout(
         if not layout or "/" in layout or f.get("unplaced") != OUTSIDE_BIOS_FOLDER:
             out.append(f)
             continue
-        stem = layout.rsplit(".", 1)[0]
+        reads = search_reads(layout)
-        reads = sorted({
-            tuple(where) for _emu, where, system, machines, any_machine, _ref in searches
-            if where and stem in rom_search_sets(emu_name, system, machines, any_machine)
-        })
         if not reads:
             out.append(f)
             continue

scripts/scraper/romfolders/es.py

@@ -526,21 +526,55 @@ def _alternative_emulators(text: str, function: str) -> dict[str, tuple[str, int
 _ROMPATH_OPTIONS = ("-rompath", "-rp")
 
 
+def _core_words(command: str) -> tuple[str, list[str]] | None:
+    """The core and the words of the content RetroArch hands it.
+
+    ES-DE starts the libretro MAME core with a quoted command line as its
+    content (`-L .../mame_libretro.so "apple2e -rompath \\"...\\" ..."`): popen
+    runs it through the shell (es-core/src/utils/PlatformUtil.cpp:231, 257),
+    and the core splits the content on spaces and quotes when it is no file
+    (retro_init.cpp parse_cmdline, mmain2).
+    """
+    core = _RA_CORE.search(command)
+    if core is None:
+        return None
+    try:
+        args = shlex.split(command)
+        at = args.index("-L")
+        content = shlex.split(args[at + 2]) if at + 2 < len(args) else []
+    except ValueError:
+        return None
+    return core.group(1), content
+
+
 def _searched_by(commands: list[tuple[str, str, int | None]], key: str, path: str) -> list[dict]:
-    """The ROM folders each standalone emulator's commands pass it, by emulator.
+    """The ROM folders each emulator's commands pass it, by emulator and core.
 
     ES-DE starts standalone MAME with `-rompath %GAMEDIR%\\;%ROMPATH%/<system>`
     and a machine, or %BASENAME% where the game is the machine. The command
-    line outranks mame.ini. %GAMEDIR% is the game's own folder, no folder a
+    line outranks mame.ini. The libretro MAME core gets the same option in
-    pack fills.
+    the command line it is handed as content, after the machine. %GAMEDIR%
+    is the game's own folder, no folder a pack fills.
     """
-    found: dict[str, dict] = {}
+    found: dict[tuple[str, str], dict] = {}
     for _label, command, line in commands:
-        emulator = _EMULATOR.search(command)
+        libretro = _core_words(command)
-        if emulator is None or _RA_CORE.search(command):
+        if libretro is not None:
-            continue
+            core, words = libretro
-        words = command.replace("\\;", ";").split()
+            if words[:1] == [core]:
-        at = next((i for i, w in enumerate(words) if w in _ROMPATH_OPTIONS), None)
+                # A first word naming the core is dropped (mmain2).
+                words = words[1:]
+            name = "retroarch"
+            at = next((i for i, w in enumerate(words) if w in _ROMPATH_OPTIONS), None)
+            machine = words[0] if words and at else ""
+        else:
+            emulator = _EMULATOR.search(command)
+            if emulator is None:
+                continue
+            core, name = "", emulator.group(1).lower()
+            words = command.replace("\\;", ";").split()
+            at = next((i for i, w in enumerate(words) if w in _ROMPATH_OPTIONS), None)
+            machine = words[at + 2] if at is not None and at + 2 < len(words) else ""
         if at is None or at + 1 >= len(words):
             continue
         reads = [
@@ -549,11 +583,10 @@ def _searched_by(commands: list[tuple[str, str, int | None]], key: str, path: st
         ]
         if not reads:
             continue
-        name = emulator.group(1).lower()
+        record = found.setdefault((name, core), {"emulator": name, "core": core, "reads": [],
-        record = found.setdefault(name, {"emulator": name, "reads": [], "machines": [],
+                                                 "machines": [], "any_machine": False,
-                                         "any_machine": False, "lines": []})
+                                                 "lines": []})
         record["reads"] += [r for r in reads if r not in record["reads"]]
-        machine = words[at + 2] if at + 2 < len(words) else ""
         if not machine or machine.startswith("%"):
             record["any_machine"] = True
         elif machine not in record["machines"]:
@@ -561,7 +594,10 @@ def _searched_by(commands: list[tuple[str, str, int | None]], key: str, path: st
         record["lines"].append(line)
     rows = []
     for record in found.values():
-        row = {"emulator": record["emulator"], "reads": record["reads"]}
+        row = {"emulator": record["emulator"]}
+        if record["core"]:
+            row["core"] = record["core"]
+        row["reads"] = record["reads"]
         if record["machines"]:
             row["machines"] = record["machines"]
         if record["any_machine"]:

tests/test_launcher_placement.py

@@ -1148,6 +1148,32 @@ class MameOnRetroDeckRomPaths(unittest.TestCase):
         self.assertEqual(places["stvbios.zip"] - {"arcade", "mame", "consolearcade"}, {"stv"})
 
 
+class LibretroMameOnEsdeRomPaths(unittest.TestCase):
+    """ES-DE hands the libretro MAME core a command line as its content,
+    with -rompath "%GAMEDIRRAW%;%ROMPATH%/<system>" after the machine. The
+    core passes it to MAME after its own <system>/mame/bios, and the later
+    value wins (retro_init.cpp:580-597, 902-940, options.cpp:260-276)."""
+
+    def test_the_rom_folders_file_records_the_core(self) -> None:
+        with (REPO_ROOT / "platforms" / "romfolders" / "retrodeck.yml").open() as f:
+            rows = yaml.safe_load(f)["folders"]
+        found = {r["folder"]: s for r in rows for s in r.get("searched_by") or []
+                 if s.get("core") == "mame"}
+        self.assertEqual(len(found), 21)
+        self.assertEqual(found["apple2"]["machines"], ["apple2e"])
+        self.assertEqual(found["atari7800"]["reads"], ["atari7800"])
+        self.assertEqual(found["atari7800"]["emulator"], "retroarch")
+
+    def test_sets_also_land_in_the_folder_the_command_names(self) -> None:
+        # RetroDECK's roms/ sits beside bios/ in the install tree.
+        for platform, read in (("retrodeck", ("", "roms/gamate/gamate.zip")),
+                               ("emudeck", ("roms", "gamate/gamate.zip"))):
+            view = libretro_view("mame", platform)
+            places = {(e.get("root") or "", e["path"]) for e in view["files"]
+                      if e["name"] == "gamate.zip"}
+            self.assertEqual(places, {("", "mame/bios/gamate.zip"), read}, platform)
+
+
 class MacBootDisksOnKnulli(unittest.TestCase):
     def test_the_hard_records_bind(self) -> None:
         # mameGenerator.py and libretroMAMEConfig.py pass the boot disk as

tests/test_romfolders_es.py

@@ -207,12 +207,19 @@ class EsdeFormat(unittest.TestCase):
         self.assertNotIn("any_machine", tano)
         self.assertEqual(tano["source_ref"], "os es_systems.xml:20")
 
-    def test_the_game_itself_as_machine_and_libretro_left_out(self) -> None:
+    def test_the_game_itself_as_machine(self) -> None:
-        (arcade,) = self.rows["arcade"]["searched_by"]
+        libretro, standalone = self.rows["arcade"]["searched_by"]
-        self.assertEqual(arcade["emulator"], "mame")
+        self.assertEqual(standalone["emulator"], "mame")
-        self.assertTrue(arcade["any_machine"])
+        self.assertNotIn("core", standalone)
-        self.assertNotIn("machines", arcade)
+        self.assertTrue(standalone["any_machine"])
+        self.assertNotIn("machines", standalone)
         self.assertNotIn("searched_by", self.rows["psx"])
+        # The libretro core reads the -rompath of the command line it is
+        # handed as content (retro_init.cpp execute_game_cmd).
+        self.assertEqual((libretro["emulator"], libretro["core"]), ("retroarch", "mame"))
+        self.assertEqual(libretro["reads"], ["arcade"])
+        self.assertTrue(libretro["any_machine"])
+        self.assertEqual(libretro["source_ref"], "os es_systems.xml:27")
 
     def test_first_command_without_alternative(self) -> None:
         rows = by_folder(scrape("esde", "esde", {"systems": {"source": "os", "path": "es_systems.xml"}}))