11_aa_custom_stream_callbacks/
11_aa_custom_stream_callbacks.rs

1use compression::{
2    ArchiveStream, ByteStream, CustomArchiveStreamCallbacks, CustomByteStreamCallbacks, FieldKey,
3    Header,
4};
5use std::cell::RefCell;
6use std::collections::VecDeque;
7use std::rc::Rc;
8
9#[derive(Default)]
10struct MemoryByteState {
11    data: Vec<u8>,
12    position: usize,
13}
14
15#[derive(Clone)]
16struct SharedByteCallbacks {
17    inner: Rc<RefCell<MemoryByteState>>,
18}
19
20impl CustomByteStreamCallbacks for SharedByteCallbacks {
21    fn write(&mut self, buffer: &[u8]) -> compression::Result<usize> {
22        let mut state = self.inner.borrow_mut();
23        let start = state.position;
24        let end = start + buffer.len();
25        if end > state.data.len() {
26            state.data.resize(end, 0);
27        }
28        state.data[start..end].copy_from_slice(buffer);
29        state.position = end;
30        Ok(buffer.len())
31    }
32
33    fn read(&mut self, buffer: &mut [u8]) -> compression::Result<usize> {
34        let mut state = self.inner.borrow_mut();
35        let available = state.data.len().saturating_sub(state.position);
36        let count = available.min(buffer.len());
37        buffer[..count].copy_from_slice(&state.data[state.position..state.position + count]);
38        state.position += count;
39        Ok(count)
40    }
41
42    fn seek(&mut self, offset: i64, whence: i32) -> compression::Result<i64> {
43        let mut state = self.inner.borrow_mut();
44        let base = match whence {
45            0 => 0_i64,
46            1 => i64::try_from(state.position).unwrap_or(i64::MAX),
47            2 => i64::try_from(state.data.len()).unwrap_or(i64::MAX),
48            _ => return Ok(-1),
49        };
50        let next = base + offset;
51        state.position = usize::try_from(next).unwrap_or(0);
52        Ok(next)
53    }
54}
55
56#[derive(Default)]
57struct MemoryArchiveState {
58    headers: VecDeque<Vec<u8>>,
59    blobs: VecDeque<(FieldKey, Vec<u8>)>,
60}
61
62#[derive(Clone)]
63struct SharedArchiveCallbacks {
64    inner: Rc<RefCell<MemoryArchiveState>>,
65}
66
67impl CustomArchiveStreamCallbacks for SharedArchiveCallbacks {
68    fn write_header(&mut self, header: &Header) -> compression::Result<()> {
69        self.inner
70            .borrow_mut()
71            .headers
72            .push_back(header.encoded_data()?);
73        Ok(())
74    }
75
76    fn write_blob(&mut self, key: FieldKey, buffer: &[u8]) -> compression::Result<()> {
77        self.inner
78            .borrow_mut()
79            .blobs
80            .push_back((key, buffer.to_vec()));
81        Ok(())
82    }
83
84    fn read_header(&mut self) -> compression::Result<Option<Header>> {
85        let Some(header) = self.inner.borrow_mut().headers.pop_front() else {
86            return Ok(None);
87        };
88        Ok(Some(Header::from_encoded_data(&header)?))
89    }
90
91    fn read_blob(&mut self, key: FieldKey, buffer: &mut [u8]) -> compression::Result<()> {
92        let (expected_key, bytes) = self.inner.borrow_mut().blobs.pop_front().expect("blob");
93        assert_eq!(expected_key, key);
94        buffer.copy_from_slice(&bytes);
95        Ok(())
96    }
97}
98
99fn main() -> Result<(), Box<dyn std::error::Error>> {
100    let byte_state = Rc::new(RefCell::new(MemoryByteState::default()));
101    let mut stream = ByteStream::custom(SharedByteCallbacks { inner: byte_state })?;
102    stream.write_all(b"hello custom stream")?;
103    stream.seek(0, 0)?;
104    let mut buffer = vec![0_u8; 19];
105    stream.read(&mut buffer)?;
106    assert_eq!(&buffer, b"hello custom stream");
107
108    let archive_state = Rc::new(RefCell::new(MemoryArchiveState::default()));
109    let mut writer = ArchiveStream::custom(SharedArchiveCallbacks {
110        inner: archive_state.clone(),
111    })?;
112    let mut header = Header::new()?;
113    header.append_field_uint(FieldKey::TYP, u64::from(b'F'))?;
114    header.append_field_string(FieldKey::PAT, "custom.txt")?;
115    header.append_field_uint(FieldKey::SIZ, buffer.len() as u64)?;
116    header.append_field_blob(FieldKey::DAT, buffer.len() as u64)?;
117    writer.write_header(&header)?;
118    writer.write_blob(FieldKey::DAT, &buffer)?;
119
120    let mut reader = ArchiveStream::custom(SharedArchiveCallbacks {
121        inner: archive_state,
122    })?;
123    let decoded_header = reader.read_header()?.expect("header");
124    assert_eq!(decoded_header.path()?.as_deref(), Some("custom.txt"));
125    let mut decoded = vec![0_u8; buffer.len()];
126    reader.read_blob(FieldKey::DAT, &mut decoded)?;
127    assert_eq!(decoded, buffer);
128
129    println!("✅ Custom AppleArchive byte/archive stream callbacks OK");
130    Ok(())
131}
11_aa_custom_stream_callbacks/11_aa_custom_stream_callbacks.rs

11_aa_custom_stream_callbacks/
11_aa_custom_stream_callbacks.rs
