2.1 KiB
Filesystem Git Database
JSGit repositories need loadAs, saveAs, loadRaw, saveRaw, readRef, and
updateRef methods.
Depending on the backing storage, there are various ways to implement these
methods.
The implementation for in-memory storage is js-git/mixins/mem-db, and there
are variants for using Github or IndexDB for storage.
The js-git/mixins/fs-db implementation provides these methods as well, but
depends on a file system interface providing readFile, readChunk,
writeFile, and readDir.
These file system methods are implemented by the git-fs-db and
git-chrome-db packages.
For the purpose of this document, => implies that the function does not block
and accepts a Node.js-style callback.
The arrow points to the type of the result.
None of these methods need to return a continuable if the nodeback is missing.
The type binary stands for whatever binary representation is appropriate for
the underlying platform.
For browsers, binary is a Uint8Array.
For Node.js, binary is a Buffer.
readFile(path) => binary | undefined
Reads the entirety of the file at the given path and produces the binary.
If the file does not exist, readFile provides undefined instead.
readChunk(path, start, end) => binary | undefined
Reads a byte range of the file at the given path.
The byte range is a half open interval, including the byte at the initial index,
and excluding the byte at the terminal index, such that the end minus the start
is the length of the resulting binary data.
The end offset may be negative, in which case it should count back from the end
of the size of the file at the path, such that the size plus the negative end is
the positive end.
If the file does not exist, readChunk provides undefined instead.
writeFile(path, binary) => undefined
Writes the given bytes to the file at the given path. The method creates any directories leading up to the path if they do not already exist.
readDir(path) => array of names | undefined
Reads the names of the entries in the directory at the given path. The names are not fully qualified paths, just the name of the entry within the given directory.