rustecal-types-string 0.1.5

String type support for rustecal TypedPublisher/TypedSubscriber
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//! # rustecal-types-string
//!
//! Provides support for sending and receiving `String` messages with rustecal.

use rustecal_core::types::DataTypeInfo;
use rustecal_pubsub::typed_publisher::PublisherMessage;
use rustecal_pubsub::typed_subscriber::SubscriberMessage;
use std::str;
use std::sync::Arc;

/// A wrapper for UTF-8 string messages used with typed eCAL pub/sub.
///
/// This type allows sending and receiving strings through the
/// `TypedPublisher` and `TypedSubscriber` APIs.
pub struct StringMessage {
    pub data: Arc<str>,
}

impl SubscriberMessage<'_> for StringMessage {
    /// Returns metadata describing this message type (`utf-8` encoded string).
    fn datatype() -> DataTypeInfo {
        DataTypeInfo {
            encoding: "utf-8".to_string(),
            type_name: "string".to_string(),
            descriptor: vec![],
        }
    }

    /// Attempts to decode a UTF-8 string from a byte buffer.
    fn from_bytes(bytes: &[u8], _data_type_info: &DataTypeInfo) -> Option<Self> {
        str::from_utf8(bytes).ok().map(|s| StringMessage {
            data: Arc::<str>::from(s),
        })
    }
}

impl PublisherMessage for StringMessage {
    /// Returns the same metadata as [`SubscriberMessage::datatype`].
    fn datatype() -> DataTypeInfo {
        <StringMessage as SubscriberMessage>::datatype()
    }

    /// Serializes the string into a byte buffer.
    fn to_bytes(&self) -> Arc<[u8]> {
        Arc::from(self.data.as_bytes())
    }
}