Data Structures

struct Chunk {
    // 32-byte BLAKE3 hash of the raw content
    hash: [u8; 32],

    // Uncompressed size in bytes
    size: u32,

    // Compression algorithm used (if any)
    compression: Option<Compression>,

    // The actual data (when loaded)
    data: Vec<u8>,
}

enum Compression {
    None,
    Zstd { level: u8 },
    Lz4,
}

// Storage format on disk:
// .dits/objects/chunks/a1/b2c3d4e5f6...
//                      ^^
//                      First 2 hex chars of hash

struct Asset {
    // Hash of the entire file content (for verification)
    content_hash: [u8; 32],

    // Hash of this asset manifest
    hash: [u8; 32],

    // Total file size in bytes
    size: u64,

    // MIME type
    mime_type: String,

    // Ordered list of chunks
    chunks: Vec<ChunkRef>,

    // Optional media metadata
    media: Option<MediaMetadata>,
}

struct ChunkRef {
    // Hash of the chunk
    hash: [u8; 32],

    // Offset in the original file
    offset: u64,

    // Size of this chunk
    size: u32,
}

struct MediaMetadata {
    // For video files
    duration_ms: Option<u64>,
    width: Option<u32>,
    height: Option<u32>,
    frame_rate: Option<f32>,
    codec: Option<String>,
    keyframe_positions: Vec<u64>,
}

struct Tree {
    // Hash of the tree (computed from sorted entries)
    hash: [u8; 32],

    // Map of paths to entries
    entries: BTreeMap<PathBuf, TreeEntry>,
}

struct TreeEntry {
    // Hash of the asset
    asset_hash: [u8; 32],

    // File mode (permissions)
    mode: FileMode,

    // File size (for quick listing)
    size: u64,
}

enum FileMode {
    Regular,     // 0o100644
    Executable,  // 0o100755
    Symlink,     // 0o120000
}

// Serialization (sorted by path for consistent hashing):
footage/scene1.mov  100644  abc123...
footage/scene2.mov  100644  def456...
project.prproj      100644  ghi789...

struct Commit {
    // Hash of this commit
    hash: [u8; 32],

    // Hash of the tree (directory snapshot)
    tree: [u8; 32],

    // Parent commit hashes (usually 1, 2 for merges)
    parents: Vec<[u8; 32]>,

    // Author information
    author: Signature,

    // Committer information (may differ from author)
    committer: Signature,

    // Commit message
    message: String,

    // Additional headers (for extensions)
    headers: HashMap<String, String>,
}

struct Signature {
    name: String,
    email: String,
    timestamp: DateTime<Utc>,
    timezone_offset: i32,  // minutes from UTC
}

// Serialization format:
tree def45678...
parent 9f8e7d6c...
author Jane Editor <jane@example.com> 1705340400 -0800
committer Jane Editor <jane@example.com> 1705340400 -0800

Add color grading to scene 1

// Reference types:

// Branch - mutable pointer to a commit
// .dits/refs/heads/main → a1b2c3d4...

// Tag - immutable pointer to a commit
// .dits/refs/tags/v1.0 → 9f8e7d6c...

// Remote tracking branch
// .dits/refs/remotes/origin/main → a1b2c3d4...

// HEAD - current position (symbolic or direct)
// .dits/HEAD → ref: refs/heads/main
// or
// .dits/HEAD → a1b2c3d4...  (detached)

struct Index {
    // Version for format compatibility
    version: u32,

    // Indexed entries
    entries: Vec<IndexEntry>,

    // Extensions (cache, resolve-undo, etc.)
    extensions: Vec<Extension>,
}

struct IndexEntry {
    // Path relative to repository root
    path: PathBuf,

    // Asset hash (staged content)
    asset_hash: [u8; 32],

    // File statistics (for change detection)
    stat: FileStat,

    // Flags
    flags: IndexFlags,
}

struct FileStat {
    ctime: SystemTime,
    mtime: SystemTime,
    dev: u64,
    ino: u64,
    mode: u32,
    uid: u32,
    gid: u32,
    size: u64,
}

struct PackFile {
    // Pack header
    magic: [u8; 4],    // "PACK"
    version: u32,
    object_count: u32,

    // Packed objects (compressed, potentially deltified)
    objects: Vec<PackedObject>,

    // Pack checksum
    checksum: [u8; 32],
}

struct PackIndex {
    // Maps object hash to offset in pack file
    // Enables O(log n) lookups
    entries: BTreeMap<[u8; 32], PackOffset>,

    // Pack file hash this index corresponds to
    pack_hash: [u8; 32],
}

// Storage:
// .dits/objects/packs/pack-a1b2c3d4.pack
// .dits/objects/packs/pack-a1b2c3d4.idx