leveldb

binding = require '../../build/Release/leveldb.node' ### An iterator allows sequential and random access to the database. Usage: var leveldb = require('leveldb'); leveldb.open('/tmp/test.db', function(err, db) { db.iterator(function(err, it) { // iterator is initially invalid it.first(function(err) { // get a key it.get('foobar', function(err, val) { console.log(val); }); }); }); }); ### exports.Iterator = class Iterator toBuffer = (val) -> if Buffer.isBuffer val then val else new Buffer val toValue = (val, options) -> unless val null else unless options?.as_buffer val.toString 'utf8' else val _wrapSeek: (callback, validate) => @_lock() throw new Error 'Illegal state' if validate and not @_valid throw new Error 'Missing callback' unless callback (err, valid, key, val) => @_unlock() @_valid = valid @_key = key @_val = val callback err if callback _lock: -> throw new Error 'Concurrent operations not supported' if @_busy @_busy = true _unlock: -> throw new Error 'Not locked' unless @_busy @_busy = false _getKey: (options) -> toValue @_key, options _getVal: (options) -> toValue @_val, options ### Constructor. @param {Native} self The underlying iterator object. ### constructor: (@self) -> @_busy = @_valid = false @_key = @_val = null ### Apply a callback over a range. The iterator will be positioned at the given key or the first key if not given, then the callback will be applied on each record moving forward until the iterator is positioned at the limit key or at an invalid key. Stops on first error. @param {String|Buffer} [startKey] Optional start key (inclusive) from which to begin applying the callback. If not given, defaults to the first key. @param {String|Buffer} [limitKey] Optional limit key (inclusive) at which to end applying the callback. @param {Object} [options] Optional options. @param {Boolean} [options.as_buffer=false] If true, data will be returned as a `Buffer`. @param {Function} callback The callback to apply to the range. @param {Error} error The error value on error, null otherwise. @param {String|Buffer} key The key. @param {String|Buffer} value The value. @param {Function} finishedCallback An optional callback being called when the limit key has been reached ### forRange: -> args = Array.prototype.slice.call arguments #Optional finished callback if typeof(args[args.length - 1]) is 'function' and typeof(args[args.length - 2]) is 'function' finishedCallback = args.pop() # required callback callback = args.pop() throw new Error 'Missing callback' unless callback # optional options options = args[args.length - 1] if typeof options is 'object' and not Buffer.isBuffer options args.pop() else options = {} # optional keys [ startKey, limitKey ] = args # for comparing end key limit = limitKey.toString 'binary' if limitKey # loop function next = (err) => return callback err if err if @_valid callback null, @_getKey(options), @_getVal(options) if not limit or limit isnt @_key.toString 'binary' @next next else if finishedCallback finishedCallback() # start loop if startKey @seek startKey, next else @first next ### True if the iterator is positioned at a valid key. ### valid: -> @_valid ### Position the iterator at a key. @param {String} key The key at which to position the iterator. @param {Function} [callback] Optional callback. @param {Error} error The error value on error, null otherwise. ### seek: (key, callback) -> @self.seek toBuffer(key), @_wrapSeek callback ### Position the iterator at the first key. @param {Function} [callback] Optional callback. @param {Error} error The error value on error, null otherwise. ### first: (callback) -> @self.first @_wrapSeek callback ### Position the iterator at the last key. @param {Function} [callback] Optional callback. @param {Error} error The error value on error, null otherwise. ### last: (callback) -> @self.last @_wrapSeek callback ### Advance the iterator to the next key. @param {Function} [callback] Optional callback. @param {Error} error The error value on error, null otherwise. ### next: (callback) -> @self.next @_wrapSeek callback, true ### Advance the iterator to the previous key. @param {Function} [callback] Optional callback. @param {Error} error The error value on error, null otherwise. ### prev: (callback) -> @self.prev @_wrapSeek callback, true ### Get the key at the current iterator position. @param {Object} [options] Optional options. @param {Boolean} [options.as_buffer=false] If true, data will be returned as a `Buffer`. @param {Function} callback The callback function. @param {Error} error The error value on error, null otherwise. @param {String|Buffer} key The key if successful. ### key: (options, callback) -> # optional options if typeof options is 'function' callback = options options = null key = @_getKey options callback? null, key key ### Get the value at the current iterator position. @param {Object} [options] Optional options. @param {Boolean} [options.as_buffer=false] If true, data will be returned as a `Buffer`. @param {Function} callback The callback function. @param {Error} error The error value on error, null otherwise. @param {String|Buffer} value The value if successful. ### value: (options, callback) -> # optional options if typeof options is 'function' callback = options options = null val = @_getVal options callback? null, val val ### Get the key and value at the current iterator position. @param {Object} [options] Optional options. @param {Boolean} [options.as_buffer=false] If true, data will be returned as a `Buffer`. @param {Function} callback The callback function. @param {Error} error The error value on error, null otherwise. @param {String|Buffer} key The key if successful. @param {String|Buffer} value The value if successful. ### current: (options, callback) -> # optional options if typeof options is 'function' callback = options options = null key = @_getKey options val = @_getVal options callback? null, key, val [key, val]