When using `getattr` you should return a stat object after the status code,
`readdir` expects an array of directory names, `open` an optional fd and
`utimens` an object with `mtime` and `atime` dates.
Most of the [FUSE api](http://fuse.sourceforge.net/doxygen/structfuse__operations.html) is supported. In general the callback for each op should be called with `cb(returnCode, [value])` where the return code is a number (`0` for OK and `< 0` for errors). See below for a list of POSIX error codes.
Both `read` and `write` passes the underlying fuse buffer without copying them to be as fast as possible.
#### `ops.init(cb)`
Called on filesystem init.
#### `ops.access(path, cb)`
Called before the filesystem accessed a file
#### `ops.statfs(path, cb)`
Called when the filesystem is being stat'ed. Accepts a fs stat object after the return code in the callback.
``` js
ops.statfs = function (path, cb) {
cb(0, {
bsize: 1000000,
frsize: 1000000,
blocks: 1000000,
bfree: 1000000,
bavail: 1000000,
files: 1000000,
ffree: 1000000,
favail: 1000000,
fsid: 1000000,
flag: 1000000,
namemax: 1000000
})
}
```
#### `ops.getattr(path, cb)`
Called when a path is being stat'ed. Accepts a stat object (similar to the one returned in `fs.stat(path, cb)`) after the return code in the callback.
``` js
ops.getattr = function (path, cb) {
cb(0, {
mtime: new Date(),
atime: new Date(),
ctime: new Date(),
size: 100,
mode: 16877,
uid: process.getuid(),
gid: process.getgid()
})
}
```
#### `ops.fgetattr(path, fd, cb)`
Same as above but is called when someone stats a file descriptor
#### `ops.flush(path, fd, cb)`
Called when a file descriptor is being flushed
#### `ops.fsync(path, fd, cb)`
Called when a file descriptor is being fsync'ed.
#### `ops.fsyncdir(path, fd, cb)`
Same as above but on a directory
#### `ops.readdir(path, cb)`
Called when a directory is being listed. Accepts an array of file/directory names after the return code in the callback
``` js
ops.readdir = function (path, cb) {
cb(0, ['file-1.txt', 'dir'])
}
```
#### `ops.truncate(path, size, cb)`
Called when a path is being truncated to a specific size
#### `ops.ftruncate(path, fd, size, cb)`
Same as above but on a file descriptor
#### `ops.readlink(path, cb)`
Called when a symlink is being resolved. Accepts a pathname (that the link should resolve to) after the return code in the callback
``` js
ops.readlink = function (path, cb) {
cb(null, 'file.txt') // make link point to file.txt
}
```
#### `ops.chown(path, uid, gid, cb)`
You can pass [mount options](http://blog.woralelandia.com/2012/07/16/fuse-mount-options/) (i.e. `direct_io` etc) as `ops.options = ['direct_io']`
Currently you have to write the result to the provided `buffer` at `offset`.
#### `ops.open(path, flags, cb)`
Called when a path is being opened. `flags` in a number containing the permissions being requested. Accepts a file descriptor after the return code in the callback.
``` js
var toFlag = function(flags) {
flags = flags & 3
if (flags === 0) return 'r'
if (flags === 1) return 'w'
return 'r+'
}
ops.open = function (path, flags, cb) {
var flag = toFlag(flags) // convert flags to a node style string
Called when contents of a file is being read. You should write the result of the read to the `buffer` and return the number of bytes written as the first argument in the callback.
If no bytes were written (read is complete) return 0 in the callback.
``` js
var data = new Buffer('hello world')
ops.read = function (path, fd, buffer, length, position, cb) {
if (position >= data.length) return cb(0) // done
var part = data.slice(position, position + length)
part.copy(buffer) // write the result of the read to the result buffer
cb(part.length) // return the number of bytes read
Called when a file is being written to. You can get the data being written in `buffer` and you should return the number of bytes written in the callback as the first argument.
``` js
ops.write = function (path, fd, buffer, length, position, cb) {
console.log('writing', buffer.slice(0, length))
cb(length) // we handled all the data
}
```
#### `ops.release(path, fd, cb)`
Called when a file descriptor is being released. Happens when a read/write is done etc.
#### `ops.releasedir(path, fd, cb)`
Same as above but for directories
#### `ops.create(path, mode, cb)`
Called when a new file is being opened.
#### `ops.utimens(path, atime, mtime, cb)`
Called when the atime/mtime of a file is being changed.
#### `ops.unlink(path, cb)`
Called when a file is being unlinked.
#### `ops.rename(src, dest, cb)`
Called when a file is being renamed.
#### `ops.link(src, dest, cb)`
Called when a new link is created.
#### `ops.symlink(src, dest, cb)`
Called when a new symlink is created
#### `ops.mkdir(path, cb)`
Called when a new directory is being created
#### `ops.rmdir(path, cb)`
Called when a directory is being removed
#### `ops.destroy(cb)`
Both `read` and `write` passes the underlying fuse buffer without copying them to be as fast as possible.
Mathias Buus
9 years ago