syntax = "proto3";

package packed;

// Header at start of file. This must be a fixed, known size. Fields cannot
// be zero.
message Header {
	// Magic number, used to quickly detect misconfigured systems or
	// corrupted files.
	fixed64 magic = 1;

	// Version of file.
	fixed64 version = 2;

	// DirectoryOffset is the byte offset from the start of the file at
	// which the Directory object may be found.
	fixed64 directory_offset = 3;

	// DirectoryLength is the byte length of the serialised Directory
	// object.
	fixed64 directory_length = 4;
}

// Directory of available files.
message Directory {
	// Files available within this pack. The key is the path of the URL to
	// serve, and the value describes the file associated with that path.
	map<string, File> files = 1;
}

// File that can be served.
message File {
	// ContentType of the file, copied directly into the "Content-Type" header.
	string content_type = 1;

	// Etag of the file (includes double quotes). Remembered by the browser
	// and used to preempt responses if it is unmodified between resource get
	// requests.
	string etag = 2;

	// Uncompressed version of the file.
	FileData uncompressed = 3;

	// Gzip compressed version of the file.
	FileData gzip = 4;

	// Brotli compressed version of the file.
	FileData brotli = 5;
}

// FileData records the position of the file data within the pack.
message FileData {
	// Offset is the start of the file, in bytes relative to the start of
	// the pack.
	fixed64 offset = 1;

	// Length is the 
	fixed64 length = 2;
}