improvements for writable abstractions

src/cfdp/pdu/eof.rs

@@ -42,10 +42,6 @@ impl EofPdu {
         &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
     }
@@ -117,7 +113,7 @@ impl EofPdu {
 
 impl WritablePduPacket for EofPdu {
     fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, PduError> {
-        let expected_len = self.written_len();
+        let expected_len = self.len_written();
         if buf.len() < expected_len {
             return Err(ByteConversionError::ToSliceTooSmall {
                 found: buf.len(),
@@ -145,6 +141,10 @@ impl WritablePduPacket for EofPdu {
         }
         Ok(current_idx)
     }
+
+    fn len_written(&self) -> usize {
+        self.pdu_header.header_len() + self.calc_pdu_datafield_len()
+    }
 }
 
 #[cfg(test)]
@@ -159,7 +159,7 @@ mod tests {
         let pdu_conf = common_pdu_conf(CrcFlag::NoCrc, LargeFileFlag::Normal);
         let pdu_header = PduHeader::new_no_file_data(pdu_conf, 0);
         let eof_pdu = EofPdu::new_no_error(pdu_header, 0x01020304, 12);
-        assert_eq!(eof_pdu.written_len(), pdu_header.header_len() + 2 + 4 + 4);
+        assert_eq!(eof_pdu.len_written(), pdu_header.header_len() + 2 + 4 + 4);
         assert_eq!(eof_pdu.file_checksum(), 0x01020304);
         assert_eq!(eof_pdu.file_size(), 12);
         assert_eq!(eof_pdu.condition_code(), ConditionCode::NoError);
@@ -174,7 +174,7 @@ mod tests {
         let res = eof_pdu.write_to_bytes(&mut buf);
         assert!(res.is_ok());
         let written = res.unwrap();
-        assert_eq!(written, eof_pdu.written_len());
+        assert_eq!(written, eof_pdu.len_written());
         verify_raw_header(eof_pdu.pdu_header(), &buf);
         let mut current_idx = eof_pdu.pdu_header().header_len();
         buf[current_idx] = FileDirectiveType::EofPdu as u8;

src/cfdp/pdu/file_data.rs

@@ -149,9 +149,6 @@ impl<'seg_meta, 'file_data> FileDataPdu<'seg_meta, 'file_data> {
         }
         len
     }
-    pub fn written_len(&self) -> usize {
-        self.pdu_header.header_len() + self.calc_pdu_datafield_len()
-    }
 
     pub fn offset(&self) -> u64 {
         self.offset
@@ -197,10 +194,10 @@ impl<'seg_meta, 'file_data> FileDataPdu<'seg_meta, 'file_data> {
 
 impl WritablePduPacket for FileDataPdu<'_, '_> {
     fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, PduError> {
-        if buf.len() < self.written_len() {
+        if buf.len() < self.len_written() {
             return Err(ByteConversionError::ToSliceTooSmall {
                 found: buf.len(),
-                expected: self.written_len(),
+                expected: self.len_written(),
             }
             .into());
         }
@@ -224,6 +221,10 @@ impl WritablePduPacket for FileDataPdu<'_, '_> {
         }
         Ok(current_idx)
     }
+
+    fn len_written(&self) -> usize {
+        self.pdu_header.header_len() + self.calc_pdu_datafield_len()
+    }
 }
 
 #[cfg(test)]
@@ -247,7 +248,7 @@ mod tests {
         assert_eq!(fd_pdu.offset(), 10);
         assert!(fd_pdu.segment_metadata().is_none());
         assert_eq!(
-            fd_pdu.written_len(),
+            fd_pdu.len_written(),
             fd_pdu.pdu_header.header_len() + core::mem::size_of::<u32>() + 4
         );
     }
@@ -327,7 +328,7 @@ mod tests {
         assert!(fd_pdu.segment_metadata().is_some());
         assert_eq!(*fd_pdu.segment_metadata().unwrap(), segment_meta);
         assert_eq!(
-            fd_pdu.written_len(),
+            fd_pdu.len_written(),
             fd_pdu.pdu_header.header_len()
                 + 1
                 + seg_metadata.len()
@@ -367,7 +368,7 @@ mod tests {
         current_idx += 1;
         assert_eq!(buf[current_idx], 4);
         current_idx += 1;
-        assert_eq!(current_idx, fd_pdu.written_len());
+        assert_eq!(current_idx, fd_pdu.len_written());
     }
 
     #[test]

src/cfdp/pdu/finished.rs

@@ -102,10 +102,6 @@ impl<'fs_responses> FinishedPdu<'fs_responses> {
         &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
     }
@@ -220,7 +216,7 @@ impl<'fs_responses> FinishedPdu<'fs_responses> {
 
 impl WritablePduPacket for FinishedPdu<'_> {
     fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, PduError> {
-        let expected_len = self.written_len();
+        let expected_len = self.len_written();
         if buf.len() < expected_len {
             return Err(ByteConversionError::ToSliceTooSmall {
                 found: buf.len(),
@@ -248,6 +244,10 @@ impl WritablePduPacket for FinishedPdu<'_> {
         }
         Ok(current_idx)
     }
+
+    fn len_written(&self) -> usize {
+        self.pdu_header.header_len() + self.calc_pdu_datafield_len()
+    }
 }
 
 #[cfg(test)]
@@ -298,7 +298,7 @@ mod tests {
         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.len_written());
         assert_eq!(written, finished_pdu.pdu_header().header_len() + 2);
         assert_eq!(
             finished_pdu.pdu_header().pdu_conf.direction,

src/cfdp/pdu/metadata.rs

@@ -174,10 +174,6 @@ impl<'src_name, 'dest_name, 'opts> MetadataPdu<'src_name, 'dest_name, 'opts> {
         })
     }
 
-    pub fn written_len(&self) -> usize {
-        self.pdu_header.header_len() + self.calc_pdu_datafield_len()
-    }
-
     fn calc_pdu_datafield_len(&self) -> usize {
         // One directve type octet and one byte of the directive parameter field.
         let mut len = 2;
@@ -256,7 +252,7 @@ impl<'src_name, 'dest_name, 'opts> MetadataPdu<'src_name, 'dest_name, 'opts> {
 
 impl WritablePduPacket for MetadataPdu<'_, '_, '_> {
     fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, PduError> {
-        let expected_len = self.written_len();
+        let expected_len = self.len_written();
         if buf.len() < expected_len {
             return Err(ByteConversionError::ToSliceTooSmall {
                 found: buf.len(),
@@ -291,17 +287,21 @@ impl WritablePduPacket for MetadataPdu<'_, '_, '_> {
         }
         Ok(current_idx)
     }
+
+    fn len_written(&self) -> usize {
+        self.pdu_header.header_len() + self.calc_pdu_datafield_len()
+    }
 }
 
 #[cfg(test)]
 pub mod tests {
-    use super::*;
     use crate::cfdp::lv::Lv;
     use crate::cfdp::pdu::metadata::{
         build_metadata_opts_from_slice, build_metadata_opts_from_vec, MetadataGenericParams,
         MetadataPdu,
     };
     use crate::cfdp::pdu::tests::{common_pdu_conf, verify_raw_header};
+    use crate::cfdp::pdu::WritablePduPacket;
     use crate::cfdp::pdu::{FileDirectiveType, PduHeader};
     use crate::cfdp::tlv::{Tlv, TlvType};
     use crate::cfdp::{
@@ -340,7 +340,7 @@ pub mod tests {
         let (src_filename, dest_filename, metadata_pdu) =
             generic_metadata_pdu(CrcFlag::NoCrc, LargeFileFlag::Normal, None);
         assert_eq!(
-            metadata_pdu.written_len(),
+            metadata_pdu.len_written(),
             metadata_pdu.pdu_header().header_len()
                 + 1
                 + 1

src/cfdp/pdu/mod.rs

@@ -3,6 +3,8 @@ use crate::cfdp::*;
 use crate::util::{UnsignedByteField, UnsignedByteFieldU8, UnsignedEnum};
 use crate::ByteConversionError;
 use crate::CRC_CCITT_FALSE;
+#[cfg(feature = "alloc")]
+use alloc::vec::Vec;
 use core::fmt::{Display, Formatter};
 #[cfg(feature = "std")]
 use std::error::Error;
@@ -150,7 +152,17 @@ impl From<TlvLvError> for PduError {
 }
 
 pub trait WritablePduPacket {
+    fn len_written(&self) -> usize;
     fn write_to_bytes(&self, buf: &mut [u8]) -> Result<usize, PduError>;
+    #[cfg(feature = "alloc")]
+    fn to_vec(&self) -> Result<Vec<u8>, PduError> {
+        // This is the correct way to do this. See
+        // [this issue](https://github.com/rust-lang/rust-clippy/issues/4483) for caveats of more
+        // "efficient" implementations.
+        let mut vec = alloc::vec![0; self.len_written()];
+        self.write_to_bytes(&mut vec)?;
+        Ok(vec)
+    }
 }
 
 /// Common configuration fields for a PDU.