right before implementing a traversal over extension chunks (#293)

Author: Byron

git-index/src/extension.rs

@@ -0,0 +1,50 @@
+use crate::{util::read_u32, Version};
+
+const MIN_SIZE: usize = 4 /* signature */ + 4 /* size */;
+
+fn decode_header(data: &[u8]) -> ([u8; 4], u32, &[u8]) {
+    let (signature, data) = data.split_at(4);
+    let (size, data) = data.split_at(4);
+    (signature.try_into().unwrap(), read_u32(size), data)
+}
+
+mod end_of_index_entry {
+    use crate::{extension, extension::EndOfIndexEntry, file::header, util::read_u32};
+
+    impl EndOfIndexEntry {
+        pub fn from_bytes(data: &[u8], object_hash: git_hash::Kind) -> Option<Self> {
+            let hash_len = object_hash.len_in_bytes();
+            if data.len() < EndOfIndexEntry::SIZE_WITH_HEADER + hash_len {
+                return None;
+            }
+
+            let start_of_eoie = data.len() - EndOfIndexEntry::SIZE_WITH_HEADER - hash_len;
+            let data = &data[start_of_eoie..][..hash_len];
+
+            let (signature, ext_size, data) = extension::decode_header(data);
+            if &signature != EndOfIndexEntry::SIGNATURE || ext_size as usize != EndOfIndexEntry::SIZE {
+                return None;
+            }
+
+            let (offset, hash) = data.split_at(4);
+            let offset = read_u32(offset) as usize;
+            if offset < header::SIZE || offset > start_of_eoie {
+                return None;
+            }
+            todo!("eoie")
+        }
+    }
+}
+
+pub struct EndOfIndexEntry {
+    /// The offset the the beginning of all extensions, or the end of all entries.
+    offset_to_extensions: u32,
+    /// The SHA1 checksum over the signature and size of all extensions.
+    checksum: git_hash::ObjectId,
+}
+
+impl EndOfIndexEntry {
+    pub const SIGNATURE: &'static [u8] = b"EOIE";
+    pub const SIZE: usize = 4 /* offset to extensions */ + git_hash::Kind::Sha1.len_in_bytes();
+    pub const SIZE_WITH_HEADER: usize = crate::extension::MIN_SIZE + Self::SIZE;
+}

git-index/src/lib.rs

@@ -7,58 +7,7 @@ use filetime::FileTime;
 
 pub mod file;
 
-pub mod extension {
-    use crate::{util::read_u32, Version};
-
-    const MIN_SIZE: usize = 4 /* signature */ + 4 /* size */;
-
-    fn decode_header(data: &[u8]) -> ([u8; 4], u32, &[u8]) {
-        let (signature, data) = data.split_at(4);
-        let (size, data) = data.split_at(4);
-        (signature.try_into().unwrap(), read_u32(size), data)
-    }
-
-    mod end_of_index_entry {
-        use crate::{extension, extension::EndOfIndexEntry, file::header, util::read_u32};
-
-        impl EndOfIndexEntry {
-            pub fn from_bytes(data: &[u8], object_hash: git_hash::Kind) -> Option<Self> {
-                let hash_len = object_hash.len_in_bytes();
-                if data.len() < EndOfIndexEntry::SIZE_WITH_HEADER + hash_len {
-                    return None;
-                }
-
-                let start_of_eoie = data.len() - EndOfIndexEntry::SIZE_WITH_HEADER - hash_len;
-                let data = &data[start_of_eoie..][..hash_len];
-
-                let (signature, ext_size, data) = extension::decode_header(data);
-                if &signature != EndOfIndexEntry::SIGNATURE || ext_size as usize != EndOfIndexEntry::SIZE {
-                    return None;
-                }
-
-                let (offset, hash) = data.split_at(4);
-                let offset = read_u32(offset) as usize;
-                if offset < header::SIZE {
-                    return None;
-                }
-                todo!("eoie")
-            }
-        }
-    }
-
-    pub struct EndOfIndexEntry {
-        /// The offset the the beginning of all extensions, or the end of all entries.
-        offset_to_extensions: u32,
-        /// The SHA1 checksum over the signature and size of all extensions.
-        checksum: git_hash::ObjectId,
-    }
-
-    impl EndOfIndexEntry {
-        pub const SIGNATURE: &'static [u8] = b"EOIE";
-        pub const SIZE: usize = 4 /* offset to extensions */ + git_hash::Kind::Sha1.len_in_bytes();
-        pub const SIZE_WITH_HEADER: usize = crate::extension::MIN_SIZE + Self::SIZE;
-    }
-}
+pub mod extension;
 
 pub mod init {
     use filetime::FileTime;