Function merge_join_docs_binary

nodedb/src/data/executor/handlers/join/mod.rs:24–46

Merge a left and optional right document into a single msgpack map, prefixing each key with its source collection name. Returns raw msgpack bytes — no JSON decode, no serde_json::Value. Uses binary scan to iterate source map entries and writes directly to the output buffer.

(
    left_bytes: &[u8],
    right_bytes: Option<&[u8]>,
    left_collection: &str,
    right_collection: &str,
)

/// Uses binary scan to iterate source map entries and writes directly
/// to the output buffer.
pub fn merge_join_docs_binary(
    left_bytes: &[u8],
    right_bytes: Option<&[u8]>,
    left_collection: &str,
    right_collection: &str,
) -> Vec<u8> {
    let left_count = count_map_entries(left_bytes);
    let right_count = right_bytes.map_or(0, count_map_entries);
    let total = left_count + right_count;

    // Estimate capacity: original data + prefixed keys overhead.
    let cap = left_bytes.len()
        + right_bytes.map_or(0, |b| b.len())
        + total * (left_collection.len().max(right_collection.len()) + 8);
    let mut buf = Vec::with_capacity(cap);

    write_map_header(&mut buf, total);
    write_prefixed_entries(&mut buf, left_bytes, left_collection);
    if let Some(rb) = right_bytes {
        write_prefixed_entries(&mut buf, rb, right_collection);
    }
    buf
}

/// Count entries in a msgpack map.
fn count_map_entries(bytes: &[u8]) -> usize {