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use crate::opc_da::{
com_utils::RemoteArray,
errors::{OpcError, OpcResult},
typedefs::ItemHandle,
};
use windows::Win32::System::Variant::VARIANT;
/// Synchronous I/O functionality (OPC DA 1.0).
///
/// Provides methods for basic synchronous read/write operations
/// with direct server communication.
pub trait SyncIoTrait {
fn interface(&self) -> OpcResult<&crate::bindings::da::IOPCSyncIO>;
/// Reads values synchronously from items.
///
/// # Arguments
/// * `source` - Whether to read from cache or device
/// * `server_handles` - Array of server item handles
///
/// # Returns
/// Tuple containing:
/// - Array of item states (value, quality, timestamp)
/// - Array of per-item error codes
///
/// # Errors
/// Returns E_INVALIDARG if server_handles is empty
fn read(
&self,
source: crate::bindings::da::tagOPCDATASOURCE,
server_handles: &[ItemHandle],
) -> OpcResult<(
RemoteArray<crate::bindings::da::tagOPCITEMSTATE>,
RemoteArray<windows::core::HRESULT>,
)> {
if server_handles.is_empty() {
return Err(OpcError::InvalidState(
"server_handles cannot be empty".to_string(),
));
}
let len = server_handles.len().try_into()?;
let mut item_values = RemoteArray::new(len);
let mut errors = RemoteArray::new(len);
// SAFETY: Calling COM interface method Read with valid server handle and output array pointers.
unsafe {
self.interface()?.Read(
source,
len,
server_handles.as_ptr() as *const u32,
item_values.as_mut_ptr(),
errors.as_mut_ptr(),
)?;
}
Ok((item_values, errors))
}
/// Writes values synchronously to items.
///
/// # Arguments
/// * `server_handles` - Array of server item handles
/// * `values` - Array of values to write
///
/// # Returns
/// Array of per-item error codes
///
/// # Errors
/// Returns E_INVALIDARG if arrays are empty or have different lengths
fn write(
&self,
server_handles: &[ItemHandle],
values: &[VARIANT],
) -> OpcResult<RemoteArray<windows::core::HRESULT>> {
if server_handles.len() != values.len() {
return Err(OpcError::InvalidState(
"server_handles and values must have the same length".to_string(),
));
}
if server_handles.is_empty() {
return Err(OpcError::InvalidState(
"server_handles cannot be empty".to_string(),
));
}
let len = server_handles.len().try_into()?;
let mut errors = RemoteArray::new(len);
// SAFETY: Calling COM interface method Write with valid server handle and value array pointers.
unsafe {
self.interface()?.Write(
len,
server_handles.as_ptr() as *const u32,
values.as_ptr(),
errors.as_mut_ptr(),
)?;
}
Ok(errors)
}
}