first basic Finished PDU impl

src/cfdp/pdu/finished.rs

@@ -1,6 +1,9 @@
-use crate::cfdp::pdu::PduHeader;
-use crate::cfdp::tlv::EntityIdTlv;
-use crate::cfdp::ConditionCode;
+use crate::cfdp::pdu::{
+    generic_length_checks_pdu_deserialization, FileDirectiveType, PduError, PduHeader,
+};
+use crate::cfdp::tlv::{EntityIdTlv, Tlv, TlvType, TlvTypeField};
+use crate::cfdp::{ConditionCode, PduType, TlvLvError};
+use crate::{ByteConversionError, SizeMissmatch};
 use num_enum::{IntoPrimitive, TryFromPrimitive};
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
@@ -34,26 +37,294 @@ pub struct FinishedPdu<'fs_responses> {
     fault_location: Option<EntityIdTlv>,
 }
 
-impl FinishedPdu<'_> {
+impl<'fs_responses> FinishedPdu<'fs_responses> {
     /// Default finished PDU: No error (no fault location field) and no filestore responses.
     pub fn new_default(
         pdu_header: PduHeader,
         delivery_code: DeliveryCode,
         file_status: FileStatus,
     ) -> Self {
-        Self {
+        Self::new_generic(
             pdu_header,
-            condition_code: ConditionCode::NoError,
+            ConditionCode::NoError,
             delivery_code,
             file_status,
-            fs_responses: None,
-            fault_location: None,
+            None,
+            None,
+        )
+    }
+
+    pub fn new_with_error(
+        pdu_header: PduHeader,
+        condition_code: ConditionCode,
+        delivery_code: DeliveryCode,
+        file_status: FileStatus,
+        fault_location: EntityIdTlv,
+    ) -> Self {
+        Self::new_generic(
+            pdu_header,
+            condition_code,
+            delivery_code,
+            file_status,
+            None,
+            Some(fault_location),
+        )
+    }
+
+    pub fn new_generic(
+        mut pdu_header: PduHeader,
+        condition_code: ConditionCode,
+        delivery_code: DeliveryCode,
+        file_status: FileStatus,
+        fs_responses: Option<&'fs_responses [u8]>,
+        fault_location: Option<EntityIdTlv>,
+    ) -> Self {
+        pdu_header.pdu_type = PduType::FileDirective;
+        let mut finished_pdu = Self {
+            pdu_header,
+            condition_code,
+            delivery_code,
+            file_status,
+            fs_responses,
+            fault_location,
+        };
+        finished_pdu.pdu_header.pdu_datafield_len = finished_pdu.calc_pdu_datafield_len() as u16;
+        finished_pdu
+    }
+    pub fn pdu_header(&self) -> &PduHeader {
+        &self.pdu_header
+    }
+
+    pub fn written_len(&self) -> usize {
+        self.pdu_header.header_len() + self.calc_pdu_datafield_len()
+    }
+
+    pub fn condition_code(&self) -> ConditionCode {
+        self.condition_code
+    }
+
+    pub fn delivery_code(&self) -> DeliveryCode {
+        self.delivery_code
+    }
+
+    pub fn file_status(&self) -> FileStatus {
+        self.file_status
+    }
+
+    pub fn filestore_responses(&self) -> Option<&'fs_responses [u8]> {
+        self.fs_responses
+    }
+
+    pub fn fault_location(&self) -> Option<EntityIdTlv> {
+        self.fault_location
+    }
+
+    fn calc_pdu_datafield_len(&self) -> usize {
+        let mut base_len = 2;
+        if let Some(fs_responses) = self.fs_responses {
+            base_len += fs_responses.len();
         }
+        if let Some(fault_location) = self.fault_location {
+            base_len += fault_location.len_full();
+        }
+        base_len
+    }
+
+    pub fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, PduError> {
+        let expected_len = self.written_len();
+        if buf.len() < expected_len {
+            return Err(ByteConversionError::ToSliceTooSmall(SizeMissmatch {
+                found: buf.len(),
+                expected: expected_len,
+            })
+            .into());
+        }
+
+        let mut current_idx = self.pdu_header.write_to_bytes(buf)?;
+        buf[current_idx] = FileDirectiveType::FinishedPdu as u8;
+        current_idx += 1;
+        buf[current_idx] = ((self.condition_code as u8) << 4)
+            | ((self.delivery_code as u8) << 2)
+            | self.file_status as u8;
+        current_idx += 1;
+        if let Some(fs_responses) = self.fs_responses {
+            buf[current_idx..current_idx + fs_responses.len()].copy_from_slice(fs_responses);
+            current_idx += fs_responses.len();
+        }
+        if let Some(fault_location) = self.fault_location {
+            current_idx += fault_location.write_to_be_bytes(&mut buf[current_idx..])?;
+        }
+        Ok(current_idx)
+    }
+
+    /// Generates [Self] from a raw bytestream.
+    pub fn from_bytes(buf: &'fs_responses [u8]) -> Result<Self, PduError> {
+        let (pdu_header, mut current_idx) = PduHeader::from_bytes(buf)?;
+        let full_len_without_crc = pdu_header.verify_length_and_checksum(buf)?;
+        let min_expected_len = current_idx + 2;
+        generic_length_checks_pdu_deserialization(buf, min_expected_len, full_len_without_crc)?;
+        let directive_type = FileDirectiveType::try_from(buf[current_idx]).map_err(|_| {
+            PduError::InvalidDirectiveType((buf[current_idx], FileDirectiveType::FinishedPdu))
+        })?;
+        if directive_type != FileDirectiveType::FinishedPdu {
+            return Err(PduError::WrongDirectiveType((
+                directive_type,
+                FileDirectiveType::FinishedPdu,
+            )));
+        }
+        current_idx += 1;
+        let condition_code = ConditionCode::try_from((buf[current_idx] >> 4) & 0b1111)
+            .map_err(|_| PduError::InvalidConditionCode((buf[current_idx] >> 4) & 0b1111))?;
+        // Unwrap is okay here for both of the following operations which can not fail.
+        let delivery_code = DeliveryCode::try_from((buf[current_idx] >> 2) & 0b1).unwrap();
+        let file_status = FileStatus::try_from(buf[current_idx] & 0b11).unwrap();
+        current_idx += 1;
+        let (fs_responses, fault_location) =
+            Self::parse_tlv_fields(current_idx, full_len_without_crc, buf)?;
+        Ok(Self {
+            pdu_header,
+            condition_code,
+            delivery_code,
+            file_status,
+            fs_responses,
+            fault_location,
+        })
+    }
+
+    fn parse_tlv_fields(
+        mut current_idx: usize,
+        full_len_without_crc: usize,
+        buf: &'fs_responses [u8],
+    ) -> Result<(Option<&'fs_responses [u8]>, Option<EntityIdTlv>), PduError> {
+        let mut fs_responses = None;
+        let mut fault_location = None;
+        let start_of_fs_responses = current_idx;
+        // There are leftover filestore response(s) and/or a fault location field.
+        while current_idx < full_len_without_crc {
+            let next_tlv = Tlv::from_bytes(&buf[current_idx..])?;
+            match next_tlv.tlv_type_field() {
+                TlvTypeField::Standard(tlv_type) => {
+                    if tlv_type == TlvType::FilestoreResponse {
+                        current_idx += next_tlv.len_full();
+                        if current_idx == full_len_without_crc {
+                            fs_responses = Some(&buf[start_of_fs_responses..current_idx]);
+                        }
+                    } else if tlv_type == TlvType::EntityId {
+                        // At least one FS response is included.
+                        if current_idx > full_len_without_crc {
+                            fs_responses = Some(&buf[start_of_fs_responses..current_idx]);
+                        }
+                        fault_location = Some(EntityIdTlv::from_bytes(&buf[current_idx..])?);
+                        current_idx += fault_location.as_ref().unwrap().len_full();
+                        // This is considered a configuration error: The entity ID has to be the
+                        // last TLV, everything else would break the whole handling of the packet
+                        // TLVs.
+                        if current_idx != full_len_without_crc {
+                            return Err(PduError::FormatError);
+                        }
+                    } else {
+                        return Err(TlvLvError::InvalidTlvTypeField((tlv_type as u8, None)).into());
+                    }
+                }
+                TlvTypeField::Custom(raw) => {
+                    return Err(TlvLvError::InvalidTlvTypeField((raw, None)).into());
+                }
+            }
+        }
+        Ok((fs_responses, fault_location))
     }
 }
 
 #[cfg(test)]
 mod tests {
+    use crate::cfdp::pdu::finished::{DeliveryCode, FileStatus, FinishedPdu};
+    use crate::cfdp::pdu::tests::{common_pdu_conf, verify_raw_header};
+    use crate::cfdp::pdu::{FileDirectiveType, PduHeader};
+    use crate::cfdp::{ConditionCode, CrcFlag, LargeFileFlag};
+
+    fn generic_finished_pdu(
+        crc_flag: CrcFlag,
+        fss: LargeFileFlag,
+        delivery_code: DeliveryCode,
+        file_status: FileStatus,
+    ) -> FinishedPdu<'static> {
+        let pdu_header = PduHeader::new_no_file_data(common_pdu_conf(crc_flag, fss), 0);
+        FinishedPdu::new_default(pdu_header, delivery_code, file_status)
+    }
+
     #[test]
-    fn test_basic() {}
+    fn test_basic() {
+        let finished_pdu = generic_finished_pdu(
+            CrcFlag::NoCrc,
+            LargeFileFlag::Normal,
+            DeliveryCode::Complete,
+            FileStatus::Retained,
+        );
+        assert_eq!(finished_pdu.condition_code(), ConditionCode::NoError);
+        assert_eq!(finished_pdu.delivery_code(), DeliveryCode::Complete);
+        assert_eq!(finished_pdu.file_status(), FileStatus::Retained);
+        assert_eq!(finished_pdu.filestore_responses(), None);
+        assert_eq!(finished_pdu.fault_location(), None);
+        assert_eq!(finished_pdu.pdu_header().pdu_datafield_len, 2);
+    }
+
+    fn generic_serialization_test_no_error(delivery_code: DeliveryCode, file_status: FileStatus) {
+        let finished_pdu = generic_finished_pdu(
+            CrcFlag::NoCrc,
+            LargeFileFlag::Normal,
+            delivery_code,
+            file_status,
+        );
+        let mut buf: [u8; 64] = [0; 64];
+        let written = finished_pdu.write_to_bytes(&mut buf);
+        assert!(written.is_ok());
+        let written = written.unwrap();
+        assert_eq!(written, finished_pdu.written_len());
+        assert_eq!(written, finished_pdu.pdu_header().header_len() + 2);
+        verify_raw_header(finished_pdu.pdu_header(), &buf);
+        let mut current_idx = finished_pdu.pdu_header().header_len();
+        assert_eq!(buf[current_idx], FileDirectiveType::FinishedPdu as u8);
+        current_idx += 1;
+        assert_eq!(
+            (buf[current_idx] >> 4) & 0b1111,
+            ConditionCode::NoError as u8
+        );
+        assert_eq!((buf[current_idx] >> 2) & 0b1, delivery_code as u8);
+        assert_eq!(buf[current_idx] & 0b11, file_status as u8);
+        assert_eq!(current_idx + 1, written);
+    }
+
+    #[test]
+    fn test_serialization_simple() {
+        generic_serialization_test_no_error(DeliveryCode::Complete, FileStatus::Retained);
+    }
+
+    #[test]
+    fn test_serialization_simple_2() {
+        generic_serialization_test_no_error(
+            DeliveryCode::Incomplete,
+            FileStatus::DiscardDeliberately,
+        );
+    }
+
+    #[test]
+    fn test_serialization_simple_3() {
+        generic_serialization_test_no_error(DeliveryCode::Incomplete, FileStatus::Unreported);
+    }
+
+    #[test]
+    fn test_deserialization_simple() {
+        let finished_pdu = generic_finished_pdu(
+            CrcFlag::NoCrc,
+            LargeFileFlag::Normal,
+            DeliveryCode::Complete,
+            FileStatus::Retained,
+        );
+        let mut buf: [u8; 64] = [0; 64];
+        finished_pdu.write_to_bytes(&mut buf).unwrap();
+        let read_back = FinishedPdu::from_bytes(&buf);
+        assert!(read_back.is_ok());
+        let read_back = read_back.unwrap();
+        assert_eq!(finished_pdu, read_back);
+    }
 }