একাধিক ফাইল পাঠানো
Files can be sent between Binder clients/servers using the ParcelFileDescriptor
type:
birthday_service/aidl/com/example/birthdayservice/IBirthdayService.aidl:
interface IBirthdayService {
/** The same thing, but loads info from a file. */
String wishFromFile(in ParcelFileDescriptor infoFile);
}
birthday_service/src/client.rs:
fn main() {
binder::ProcessState::start_thread_pool();
let service = connect().expect("Failed to connect to BirthdayService");
// Open a file and put the birthday info in it.
let mut file = File::create("/data/local/tmp/birthday.info").unwrap();
writeln!(file, "{name}")?;
writeln!(file, "{years}")?;
// Create a `ParcelFileDescriptor` from the file and send it.
let file = ParcelFileDescriptor::new(file);
service.wishFromFile(&file)?;
}
birthday_service/src/lib.rs:
impl IBirthdayService for BirthdayService {
fn wishFromFile(
&self,
info_file: &ParcelFileDescriptor,
) -> binder::Result<String> {
// Convert the file descriptor to a `File`. `ParcelFileDescriptor` wraps
// an `OwnedFd`, which can be cloned and then used to create a `File`
// object.
let mut info_file = info_file
.as_ref()
.try_clone()
.map(File::from)
.expect("Invalid file handle");
let mut contents = String::new();
info_file.read_to_string(&mut contents).unwrap();
let mut lines = contents.lines();
let name = lines.next().unwrap();
let years: i32 = lines.next().unwrap().parse().unwrap();
Ok(format!("Happy Birthday {name}, congratulations with the {years} years!"))
}
}
ParcelFileDescriptor
wraps anOwnedFd
, and so can be created from aFile
(or any other type that wraps anOwnedFd
), and can be used to create a newFile
handle on the other side.- Other types of file descriptors can be wrapped and sent, e.g. TCP, UDP, and UNIX sockets.