feat: hide an Android BIOS folder from the gallery

An install on Android leaves an empty .nomedia in the BIOS folder. MediaProvider hides a folder holding one and every folder below it (FileUtils.java:1587-1629, ModernMediaScanner.java:845-846, a183e2b9), and RetroArch writes none: the samples, overlays and videos of system/ showed in the gallery and music apps. --check and --dry-run write nothing.

install.ps1

@@ -16,7 +16,7 @@
     # and Invoke-WebRequest throws on a cut transfer before the hash is read:
     # the site's build rewrites this line there (scripts/sitebootstrap.py).
     $mismatchAdvice = "The download was most likely cut short: try again. Within minutes of an update of this project the two files can come from caches of different ages. Waiting five minutes settles that."
-    $defaultInstallSha256 = "bba0f7cd7677fb7f4d767504412843cf3809c03b91808c7c7772f17758893d50"
+    $defaultInstallSha256 = "192ecdd781447b69967d5d335911fb34887757ee1bf9b6c000ad68a62b17de4b"
     $maximumInstallerBytes = 2MB
     $installerExit = 0
     $installer = if ($PSScriptRoot) { Join-Path $PSScriptRoot "install.py" } else { $null }

install.py

@@ -3132,6 +3132,29 @@ def fold_case_twins(files: list[dict]) -> tuple[list[dict], list[str]]:
     return kept, folded
 
 
+# Android's media scanner marks a folder holding a .nomedia file hidden, and
+# every folder below it (MediaProvider a183e2b9, FileUtils.java:1587-1629
+# isDirectoryHidden, ModernMediaScanner.java:845-846 and 1017-1020). Without
+# one, the samples, overlays and videos of a BIOS folder in shared storage
+# showed in the phone's gallery and music apps. RetroArch writes none
+# (libretro-common/file/file_path_io.c:194 only skips one).
+NOMEDIA = ".nomedia"
+
+
+def hide_from_media_scanner(folder: Path) -> bool:
+    """Leave an empty .nomedia in folder, True when this call wrote it."""
+    marker = folder / NOMEDIA
+    if not _is_dir(folder) or _exists(marker):
+        return False
+    try:
+        marker.touch()
+    except OSError as exc:
+        print(f"  {NOMEDIA} not written in {shown_path(folder)}: {exc.strerror}",
+              file=sys.stderr)
+        return False
+    return True
+
+
 def installed_cores(dirs: list[Path]) -> list[str]:
     """The cores present in these directories, by the name the buildbot uses.
 
@@ -16343,6 +16366,10 @@ def _install(args: argparse.Namespace, real_stdout: TextIO) -> None:
                     failures.append((where, f"{NOT_KEPT} ({reason})"))
                     total_errors += 1
 
+        if os_type == "android" and not args.check and hide_from_media_scanner(bios_path):
+            print(f"  Added {NOMEDIA} to {shown_path(bios_path)}: the gallery and music "
+                  "apps leave its images, sounds and videos out")
+
         # Standalone copies
         if (
             manifest.get("standalone_copies")

install.sh

@@ -23,7 +23,7 @@ DEFAULT_INSTALL_URL="https://raw.githubusercontent.com/Abdess/retrobios/main/ins
 # curl or wget stop on a cut transfer before the hash is read: the site's
 # build rewrites this line there (scripts/sitebootstrap.py).
 MISMATCH_ADVICE="The download was most likely cut short: try again. Within minutes of an update of this project the two files can come from caches of different ages. Waiting five minutes settles that."
-DEFAULT_INSTALL_SHA256="bba0f7cd7677fb7f4d767504412843cf3809c03b91808c7c7772f17758893d50"
+DEFAULT_INSTALL_SHA256="192ecdd781447b69967d5d335911fb34887757ee1bf9b6c000ad68a62b17de4b"
 MAX_INSTALLER_BYTES=2097152
 
 cleanup() {

install/launchers/index.json

@@ -27,8 +27,8 @@
         {
           "dest": "roms/ports/retrobios/install.py",
           "repo_path": "install.py",
-          "size": 1125268,
-          "sha256": "bba0f7cd7677fb7f4d767504412843cf3809c03b91808c7c7772f17758893d50",
+          "size": 1126407,
+          "sha256": "192ecdd781447b69967d5d335911fb34887757ee1bf9b6c000ad68a62b17de4b",
           "executable": false
         },
         {
@@ -71,8 +71,8 @@
     "muos": {
       "archive": {
         "dest": "ARCHIVE/RetroBIOS.muxapp",
-        "size": 1178895,
-        "sha256": "814d80f123e59f5192631842d53a4808bf373599ced857f4622612ffbc25322b"
+        "size": 1180034,
+        "sha256": "14c4e4b762ec84fe30d2cf0baed58d1022c3423e05118b43dbccfbaff5e4d84a"
       },
       "members": [
         {
@@ -92,8 +92,8 @@
         {
           "name": "RetroBIOS/install.py",
           "repo_path": "install.py",
-          "size": 1125268,
-          "sha256": "bba0f7cd7677fb7f4d767504412843cf3809c03b91808c7c7772f17758893d50",
+          "size": 1126407,
+          "sha256": "192ecdd781447b69967d5d335911fb34887757ee1bf9b6c000ad68a62b17de4b",
           "executable": false
         },
         {
@@ -166,8 +166,8 @@
         {
           "dest": ".config/modules/retrobios/install.py",
           "repo_path": "install.py",
-          "size": 1125268,
-          "sha256": "bba0f7cd7677fb7f4d767504412843cf3809c03b91808c7c7772f17758893d50",
+          "size": 1126407,
+          "sha256": "192ecdd781447b69967d5d335911fb34887757ee1bf9b6c000ad68a62b17de4b",
           "executable": false
         },
         {

tests/test_install_filesystems.py

@@ -0,0 +1,64 @@
+"""What an install does for the device and file system it lands on."""
+
+from __future__ import annotations
+
+import tests  # noqa: F401  offline, scratch under tmp/, the suite's own cache
+
+import subprocess
+import sys
+import unittest
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(REPO_ROOT))
+sys.path.insert(0, str(REPO_ROOT / "tests"))
+
+from test_install_selection import FakeRepository  # noqa: E402
+
+
+class AndroidMediaScanner(unittest.TestCase):
+    """Without a .nomedia the BIOS folder's samples, overlays and videos
+    showed in the phone's gallery and music apps."""
+
+    def setUp(self):
+        self.repo = FakeRepository().__enter__()
+        self.addCleanup(self.repo.__exit__)
+
+    def _run(self, os_name: str, *options: str):
+        proc = subprocess.run(self.repo.command("--yes", "--no-input", *options),
+                              env={**self.repo.env(), "RETROBIOS_OS": os_name},
+                              capture_output=True, text=True, timeout=60,
+                              stdin=subprocess.DEVNULL)
+        return self.repo, proc
+
+    def test_an_android_install_writes_one(self):
+        repo, proc = self._run("android")
+        self.assertEqual(proc.returncode, 0, proc.stdout + proc.stderr)
+        marker = repo.dest / ".nomedia"
+        self.assertTrue(marker.is_file())
+        self.assertEqual(marker.stat().st_size, 0)
+        self.assertIn("Added .nomedia", proc.stdout)
+
+    def test_a_second_run_leaves_it_and_says_nothing(self):
+        self._run("android")
+        _, proc = self._run("android")
+        self.assertEqual(proc.returncode, 0, proc.stdout + proc.stderr)
+        self.assertNotIn("Added .nomedia", proc.stdout)
+        # The marker is not a file of the list: the check finds all in place.
+        _, check = self._run("android", "--check")
+        self.assertEqual(check.returncode, 0, check.stdout + check.stderr)
+
+    def test_a_check_and_a_dry_run_write_nothing(self):
+        for options in (("--check",), ("--dry-run",)):
+            with self.subTest(options=options):
+                self._run("android", *options)
+                self.assertFalse((self.repo.dest / ".nomedia").exists())
+
+    def test_other_systems_get_none(self):
+        repo, proc = self._run("linux")
+        self.assertEqual(proc.returncode, 0, proc.stdout + proc.stderr)
+        self.assertFalse((repo.dest / ".nomedia").exists())
+
+
+if __name__ == "__main__":
+    unittest.main()

wiki/faq.md

@@ -101,6 +101,11 @@ Fill it from a computer or point `--from-pack` at your ZIP: [Without a network](
 `--from` copies BIOS files from an old card or backup:
 [Copy from an old card](installer.md#copy-from-an-old-card).
 
+## BIOS pictures or sounds in my phone's gallery?
+
+An empty file named `.nomedia` in the BIOS folder hides them. The installer
+adds it on Android: [Android](installer.md#android).
+
 ## My setup is not in the list
 
 - Name your emulator's BIOS folder with `--dest`.

wiki/installer.md

@@ -1461,6 +1461,13 @@ elsewhere. A custom BIOS directory is still named directly:
 python install.py --platform retroarch --dest /storage/emulated/0/RetroArch/system
 ```
 
+An install on Android leaves an empty `.nomedia` in the BIOS folder. Android's
+media scanner hides a folder holding one, and every folder below it
+(MediaProvider, `FileUtils.java` `isDirectoryHidden`), so the samples,
+overlays and videos of the BIOS folder stay out of the gallery and music
+apps. RetroArch writes none. A run that finds one already there leaves it,
+and `--check` and `--dry-run` write nothing.
+
 ## On a handheld { #on-a-handheld-the-retrobios-port }
 
 RetroBIOS also runs on the handheld itself, in the