implementing TreeItem and parsing for extentdata

- implementing extentdata as an enum of either Inline + data bytes or not
inline (preallocated and whatever)
- accessor for name component in ItemWithName<T>

btrfs/src/structs.rs

@@ -229,8 +229,29 @@ macro_rules! impl_parse_try_from_ctx {
     };
 }
 
-impl_parse_try_from_ctx!(Chunk, Header, Key, RootItem, INodeItem, INodeRef, DirItem);
-impl_try_from_ctx!(Key, Chunk, Header, Superblock, RootItem, INodeItem, INodeRef, DirItem);
+impl_parse_try_from_ctx!(
+    Chunk,
+    Header,
+    Key,
+    RootItem,
+    INodeItem,
+    INodeRef,
+    DirItem,
+    ExtentData1,
+    ExtentData2
+);
+impl_try_from_ctx!(
+    Key,
+    Chunk,
+    Header,
+    Superblock,
+    RootItem,
+    INodeItem,
+    INodeRef,
+    DirItem,
+    ExtentData1,
+    ExtentData2
+);
 
 const MAX_LABEL_SIZE: usize = 0x100;
 const SYS_CHUNK_ARRAY_SIZE: usize = 0x800;
@@ -294,31 +315,71 @@ pub struct ChunkItemStripe {
     dev_uuid: Uuid,
 }
 
-#[repr(C, packed(1))]
-#[derive(Debug, Clone, Copy, Pod, Zeroable)]
-pub struct ExtentData {
-    generation: u64,
-    decoded_size: u64,
-    compression: u8,
-    encryption: u8,
-    encoding: u16,
-    ty: u8,
-    data: [u8; 1],
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub enum ExtentDataType {
+    Inline,
+    Regular,
+    PreAlloc,
+}
+
+#[derive(Debug, Clone)]
+pub enum ExtentData {
+    Inline { header: ExtentData1, data: Vec<u8> },
+    Other(ExtentData2),
+}
+
+impl Parseable for ExtentData {
+    fn parse(bytes: &[u8]) -> Result<Self> {
+        let header = ExtentData1::parse(bytes)?;
+
+        let extent = match header.ty() {
+            ExtentDataType::Inline => {
+                let data = bytes[size_of::<ExtentData1>()..].to_vec();
+                Self::Inline { header, data }
+            }
+            _ => Self::Other(ExtentData2::parse(bytes)?),
+        };
+
+        Ok(extent)
+    }
 }
 
 #[repr(C, packed(1))]
-#[derive(Debug, Clone, Copy, Pod, Zeroable)]
+#[derive(Debug, Clone, Copy, FromBytes, AsBytes)]
+pub struct ExtentData1 {
+    generation: U64<LE>,
+    decoded_size: U64<LE>,
+    compression: u8,
+    encryption: u8,
+    encoding: U16<LE>,
+    ty: u8,
+}
+
+impl ExtentData1 {
+    pub fn ty(&self) -> ExtentDataType {
+        match self.ty {
+            0 => ExtentDataType::Inline,
+            1 => ExtentDataType::Regular,
+            2 => ExtentDataType::PreAlloc,
+            _ => panic!("extentdatatype of invalid"),
+        }
+    }
+}
+
+#[repr(C, packed(1))]
+#[derive(Debug, Clone, Copy, FromBytes, AsBytes)]
 pub struct ExtentData2 {
-    address: u64,
-    size: u64,
-    offset: u64,
-    num_bytes: u64,
+    header: ExtentData1,
+    address: U64<LE>,
+    size: U64<LE>,
+    offset: U64<LE>,
+    num_bytes: U64<LE>,
 }
 
 #[repr(C, packed(1))]
 #[derive(Debug, Clone, Copy, FromBytes, AsBytes)]
 pub struct INodeRef {
-    index: U64<LE>,
+    pub index: U64<LE>,
     name_len: U16<LE>,
 }
 
@@ -878,6 +939,11 @@ where
     pub fn item(&self) -> &I {
         &self.inner
     }
+
+    pub fn name(&self) -> &Vec<u8> {
+        &self.name
+    }
+
     pub fn name_as_str(&self) -> core::result::Result<&str, core::str::Utf8Error> {
         core::str::from_utf8(&self.name)
     }
@@ -907,8 +973,10 @@ pub struct InodeRef {
 }
 
 #[repr(C, packed)]
-#[derive(Debug, Clone, PartialEq, Eq, Copy, FromBytes, AsBytes)]
+#[derive(Derivative, Clone, PartialEq, Eq, Copy, FromBytes, AsBytes)]
+#[derivative(Debug)]
 pub struct Header {
+    #[derivative(Debug = "ignore")]
     pub csum: [u8; 32],
     pub fsid: Uuid,
     /// Which block this node is supposed to live in
@@ -946,6 +1014,7 @@ use alloc::vec::Vec;
 pub enum TreeItem {
     Chunk(Chunk),
     Root(RootItem),
+    ExtentData(ExtentData),
     DirItem(Vec<DirItemEntry>),
     DirIndex(DirItemEntry),
     INodeItem(INodeItem),
@@ -989,6 +1058,12 @@ impl From<INodeRefEntry> for TreeItem {
     }
 }
 
+impl From<ExtentData> for TreeItem {
+    fn from(value: ExtentData) -> Self {
+        Self::ExtentData(value)
+    }
+}
+
 impl TreeItem {
     pub fn parse(item: &Item, bytes: &[u8]) -> Result<Self> {
         Ok(match item.key.ty() {
@@ -998,20 +1073,13 @@ impl TreeItem {
             ObjectType::DirIndex => DirItemEntry::parse(bytes)?.into(),
             ObjectType::INodeItem => INodeItem::parse(bytes)?.into(),
             ObjectType::INodeRef => INodeRefEntry::parse(bytes)?.into(),
+            ObjectType::ExtentData => ExtentData::parse(bytes)?.into(),
             _ => TreeItem::Unimplemented,
         })
     }
 
-    pub fn as_dir_item(&self) -> Option<&Vec<DirItemEntry>> {
-        if let Self::DirItem(v) = self {
-            Some(v)
-        } else {
-            None
-        }
-    }
-
-    pub fn as_dir_index(&self) -> Option<&DirItemEntry> {
-        if let Self::DirIndex(v) = self {
+    pub fn as_extent_data(&self) -> Option<&ExtentData> {
+        if let Self::ExtentData(v) = self {
             Some(v)
         } else {
             None
@@ -1035,6 +1103,38 @@ impl TreeItem {
             None
         }
     }
+
+    pub fn as_dir_item(&self) -> Option<&Vec<DirItemEntry>> {
+        if let Self::DirItem(v) = self {
+            Some(v)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_dir_index(&self) -> Option<&DirItemEntry> {
+        if let Self::DirIndex(v) = self {
+            Some(v)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_inode_ref(&self) -> Option<&INodeRefEntry> {
+        if let Self::INodeRef(v) = self {
+            Some(v)
+        } else {
+            None
+        }
+    }
+
+    pub fn as_inode_item(&self) -> Option<&INodeItem> {
+        if let Self::INodeItem(v) = self {
+            Some(v)
+        } else {
+            None
+        }
+    }
 }
 
 #[derive(Debug, Clone)]