internal static Java.IO.File GetTemporaryRootDirectory()
{
// If we specifically want the internal storage, no extra checks are needed, we have permission
if (TemporaryLocation == FileProviderLocation.Internal)
{
return(Platform.AppContext.CacheDir);
}
// If we explicitly want only external locations we need to do some permissions checking
var externalOnly = TemporaryLocation == FileProviderLocation.External;
// Check to see if we are >= API Level 19 (KitKat) since we don't need to declare the permission on these API levels to save to the external cache/storage
// If we're not on 19 or higher we do need to check for permissions, but if we aren't limiting to external only, don't throw an exception if the
// permission wasn't declared because we can always fall back to internal cache
var hasPermission = Platform.HasApiLevel(BuildVersionCodes.Kitkat);
if (!hasPermission)
{
hasPermission = Permissions.IsDeclaredInManifest(global::Android.Manifest.Permission.WriteExternalStorage);
if (!hasPermission && externalOnly)
{
throw new PermissionException("Cannot access external storage, the explicitly chosen FileProviderLocation.");
}
}
// make sure the external storage is available
var hasExternalMedia = Platform.AppContext.ExternalCacheDir != null && IsMediaMounted(Platform.AppContext.ExternalCacheDir);
// undo all the work if we have requested a fail (mainly for testing)
if (AlwaysFailExternalMediaAccess)
{
hasExternalMedia = false;
}
// fail if we need the external storage, but there is none
if (externalOnly && !hasExternalMedia)
{
throw new InvalidOperationException("Unable to access the external storage, the media is not mounted.");
}
// based on permssions, return the correct directory
// if permission were required, then it would have already thrown
return(hasPermission && hasExternalMedia
? Platform.AppContext.ExternalCacheDir
: Platform.AppContext.CacheDir);
}
static string CacheContentFile(AndroidUri uri)
{
if (!uri.Scheme.Equals(UriSchemeContent, StringComparison.OrdinalIgnoreCase))
{
return(null);
}
Debug.WriteLine($"Copying content URI to local cache: '{uri}'");
// open the source stream
using var srcStream = OpenContentStream(uri, out var extension);
if (srcStream == null)
{
return(null);
}
// resolve or generate a valid destination path
#pragma warning disable CS0618
var filename = GetColumnValue(uri, MediaStore.Files.FileColumns.DisplayName) ?? Guid.NewGuid().ToString("N");
#pragma warning restore CS0618
if (!Path.HasExtension(filename) && !string.IsNullOrEmpty(extension))
{
filename = Path.ChangeExtension(filename, extension);
}
// create a temporary file
var hasPermission = Permissions.IsDeclaredInManifest(global::Android.Manifest.Permission.WriteExternalStorage);
var root = hasPermission
? Platform.AppContext.ExternalCacheDir
: Platform.AppContext.CacheDir;
var tmpFile = GetEssentialsTemporaryFile(root, filename);
// copy to the destination
using var dstStream = File.Create(tmpFile.CanonicalPath);
srcStream.CopyTo(dstStream);
return(tmpFile.CanonicalPath);
}