// SPDX-FileCopyrightText: edef <edef@unfathomable.blue>
// SPDX-License-Identifier: OSL-3.0 OR MIT OR Apache-2.0

syntax = "proto3";

package tvix.castore.v1;

option go_package = "code.tvl.fyi/tvix/castore-go;castorev1";

// A Directory can contain Directory, File or Symlink nodes.
// Each of these nodes have a name attribute, which is the basename in that
// directory and node type specific attributes.
// The name attribute:
//  - MUST not contain slashes or null bytes
//  - MUST not be '.' or '..'
//  - MUST be unique across all three lists
// Elements in each list need to be lexicographically ordered by the name
// attribute.
message Directory {
  repeated DirectoryNode directories = 1;
  repeated FileNode files = 2;
  repeated SymlinkNode symlinks = 3;
}

// A DirectoryNode represents a directory in a Directory.
message DirectoryNode {
  // The (base)name of the directory
  bytes name = 1;
  // The blake3 hash of a Directory message, serialized in protobuf canonical form.
  bytes digest = 2;
  // Number of child elements in the Directory referred to by `digest`.
  // Calculated by summing up the numbers of `directories`, `files` and
  // `symlinks`, and for each directory, its size field. Used for inode number
  // calculation.
  // This field is precisely as verifiable as any other Merkle tree edge.
  // Resolve `digest`, and you can compute it incrementally. Resolve the entire
  // tree, and you can fully compute it from scratch.
  // A credulous implementation won't reject an excessive size, but this is
  // harmless: you'll have some ordinals without nodes. Undersizing is obvious
  // and easy to reject: you won't have an ordinal for some nodes.
  uint64 size = 3;
}

// A FileNode represents a regular or executable file in a Directory.
message FileNode {
  // The (base)name of the file
  bytes name = 1;
  // The blake3 digest of the file contents
  bytes digest = 2;
  // The file content size
  uint64 size = 3;
  // Whether the file is executable
  bool executable = 4;
}

// A SymlinkNode represents a symbolic link in a Directory.
message SymlinkNode {
  // The (base)name of the symlink
  bytes name = 1;
  // The target of the symlink.
  bytes target = 2;
}

// A Node is either a DirectoryNode, FileNode or SymlinkNode.
message Node {
  oneof node {
    DirectoryNode directory = 1;
    FileNode file = 2;
    SymlinkNode symlink = 3;
  }
}
