Mob.Bt: Bluetooth Classic peripheral (HFP/SPP/HID) - #9
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Adds a Bluetooth Classic API for Android. iOS returns :unsupported
(Classic profiles need MFi). Companion to mob_new#3 (Kotlin / manifest
/ JNI templates).
## Elixir surface
- lib/mob/bt.ex — Mob.Bt (discovery, pairing, disconnect)
- lib/mob/bt/hfp.ex — HFP profile (connect, SCO audio, vendor AT)
- lib/mob/bt/spp.ex — SPP profile (RFCOMM client)
- lib/mob/bt/hid.ex — HID profile (raw input reports)
Vendor AT subscribe takes a caller-specified `:company_ids` keyword so
apps can target specific BT SIG company codes per call (Hytera 313,
Apple 76, Qualcomm 10, Plantronics 1117, etc.). Empty list = no events.
## NIF surface
16 NIFs in android/jni/mob_nif.zig:
- bt_list_paired/0, bt_start_discovery/0, bt_cancel_discovery/0
- bt_pair/1, bt_unpair/1, bt_disconnect/1
- bt_hfp_connect/1, bt_hfp_subscribe_vendor_at/2,
bt_hfp_send_vendor_at/3, bt_hfp_start_sco/1, bt_hfp_stop_sco/1,
bt_hfp_send_audio/2 (DIRTY_IO)
- bt_spp_connect/1, bt_spp_write/2 (DIRTY_IO)
- bt_hid_connect/1, bt_hid_subscribe_raw/1
33 mob_deliver_bt_* exports the JNI thunks (in mob_new#3's generated
beam_jni.c) invoke when Kotlin emits BT events. Each builds a 4-tuple
`{:bt | :bt_hfp | :bt_spp | :bt_hid, tag, session_or_nil, payload}`
and posts it to the originating pid.
BridgeMethods gains 16 jmethodID slots; nif_load caches them via
cacheOptional. The bt_* NIFs short-circuit with
`{:bt, :error, nil, %{reason: :unsupported}}` when the matching
methodID is null, so apps from an older mob_new template still boot.
BT atom cache (~30 atoms + map keys) is initialised once at nif_load.
The paired-list streaming accumulator is a 16-slot fixed-size table
protected by its own mutex, holding up to 128 entries per concurrent
caller so multiple processes can list paired devices simultaneously.
## Verified
- mix test: 760 passed, 0 failed
- zig ast-check android/jni/mob_nif.zig exits 0GenericJam added a commit
that referenced
this pull request
May 16, 2026
…eripheral Adds a Bluetooth Classic API for Android covering HFP (audio + vendor AT commands), SPP (RFCOMM byte streams), and HID (input reports). iOS returns :unsupported (Classic profiles need MFi). Companion to mob_new#4 (BT codegen templates). Either order works at build time; runtime short-circuits to :unsupported when the matching MobBridge methodID isn't present. Includes follow-on review fixes: drops a Jason.encode! call that would have failed at runtime (Jason is dev-only), dedupes the encode_device helper across modules, and adds 14 unit tests covering the JSON encoder surface.
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Adds a Bluetooth Classic API for Android. iOS returns
:unsupported(Classic profiles need MFi).Companion to GenericJam/mob_new#4 (BT codegen templates). Either order works at build time — runtime short-circuits to
:unsupportedwhen the matching MobBridge methodID isn't present — but the user-visible feature only works end-to-end with both in place.See the commit message for full details (Elixir surface, NIF inventory, atom cache, paired-list streaming accumulator, JNI signatures).
cc @GenericJam