refactor

* put error into more specific spot and export it

Author: Byron

gix-pack/src/cache/delta/traverse/mod.rs

@@ -42,7 +42,7 @@ pub enum Error {
     #[error("Failed to spawn thread when switching to work-stealing mode")]
     SpawnThread(#[from] std::io::Error),
     #[error(transparent)]
-    Delta(#[from] crate::data::delta::Error),
+    Delta(#[from] crate::data::delta::apply::Error),
 }
 
 /// Additional context passed to the `inspect_object(…)` function of the [`Tree::traverse()`] method.

gix-pack/src/data/delta.rs

@@ -1,18 +1,21 @@
-/// Returned by [`Tree::traverse()`]
-#[derive(thiserror::Error, Debug)]
-#[allow(missing_docs)]
-pub enum Error {
-    #[error("Encountered unsupported command code: 0")]
-    UnsupportedCommandCode,
-    #[error("Delta copy from base: byte slices must match")]
-    DeltaCopyBaseSliceMismatch,
-    #[error("Delta copy data: byte slices must match")]
-    DeltaCopyDataSliceMismatch,
+///
+pub mod apply {
+    /// Returned when failing to apply deltas.
+    #[derive(thiserror::Error, Debug)]
+    #[allow(missing_docs)]
+    pub enum Error {
+        #[error("Encountered unsupported command code: 0")]
+        UnsupportedCommandCode,
+        #[error("Delta copy from base: byte slices must match")]
+        DeltaCopyBaseSliceMismatch,
+        #[error("Delta copy data: byte slices must match")]
+        DeltaCopyDataSliceMismatch,
+    }
 }
 
 /// Given the decompressed pack delta `d`, decode a size in bytes (either the base object size or the result object size)
 /// Equivalent to [this canonical git function](https://github.com/git/git/blob/311531c9de557d25ac087c1637818bd2aad6eb3a/delta.h#L89)
-pub fn decode_header_size(d: &[u8]) -> (u64, usize) {
+pub(crate) fn decode_header_size(d: &[u8]) -> (u64, usize) {
     let mut i = 0;
     let mut size = 0u64;
     let mut consumed = 0;
@@ -27,7 +30,7 @@ pub fn decode_header_size(d: &[u8]) -> (u64, usize) {
     (size, consumed)
 }
 
-pub fn apply(base: &[u8], mut target: &mut [u8], data: &[u8]) -> Result<(), Error> {
+pub(crate) fn apply(base: &[u8], mut target: &mut [u8], data: &[u8]) -> Result<(), apply::Error> {
     let mut i = 0;
     while let Some(cmd) = data.get(i) {
         i += 1;
@@ -67,12 +70,12 @@ pub fn apply(base: &[u8], mut target: &mut [u8], data: &[u8]) -> Result<(), Erro
                 }
                 let ofs = ofs as usize;
                 std::io::Write::write(&mut target, &base[ofs..ofs + size as usize])
-                    .map_err(|_e| Error::DeltaCopyBaseSliceMismatch)?;
+                    .map_err(|_e| apply::Error::DeltaCopyBaseSliceMismatch)?;
             }
-            0 => return Err(Error::UnsupportedCommandCode),
+            0 => return Err(apply::Error::UnsupportedCommandCode),
             size => {
                 std::io::Write::write(&mut target, &data[i..i + *size as usize])
-                    .map_err(|_e| Error::DeltaCopyDataSliceMismatch)?;
+                    .map_err(|_e| apply::Error::DeltaCopyDataSliceMismatch)?;
                 i += *size as usize;
             }
         }

gix-pack/src/data/file/decode/mod.rs

@@ -20,7 +20,7 @@ pub enum Error {
     #[error("Entry too large to fit in memory")]
     OutOfMemory,
     #[error(transparent)]
-    Delta(#[from] crate::data::delta::Error),
+    Delta(#[from] crate::data::delta::apply::Error),
 }
 
 impl From<TryReserveError> for Error {

gix-pack/src/data/mod.rs

@@ -128,4 +128,5 @@ impl File {
     }
 }
 
-pub(crate) mod delta;
+///
+pub mod delta;