| // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| /// Generic utility functions. Stuff that should possibly be in core. |
| library utils; |
| |
| import 'dart:crypto'; |
| import 'dart:isolate'; |
| import 'dart:uri'; |
| |
| /// A pair of values. |
| class Pair<E, F> { |
| E first; |
| F last; |
| |
| Pair(this.first, this.last); |
| |
| String toString() => '($first, $last)'; |
| |
| bool operator==(other) { |
| if (other is! Pair) return false; |
| return other.first == first && other.last == last; |
| } |
| |
| int get hashCode => first.hashCode ^ last.hashCode; |
| } |
| |
| // TODO(rnystrom): Move into String? |
| /// Pads [source] to [length] by adding spaces at the end. |
| String padRight(String source, int length) { |
| final result = new StringBuffer(); |
| result.add(source); |
| |
| while (result.length < length) { |
| result.add(' '); |
| } |
| |
| return result.toString(); |
| } |
| |
| /// Runs [fn] after [future] completes, whether it completes successfully or |
| /// not. Essentially an asynchronous `finally` block. |
| always(Future future, fn()) { |
| var completer = new Completer(); |
| future.then((_) => fn()); |
| future.handleException((_) { |
| fn(); |
| return false; |
| }); |
| } |
| |
| /// Flattens nested collections into a single list containing only non-list |
| /// elements. |
| List flatten(Collection nested) { |
| var result = []; |
| helper(list) { |
| for (var element in list) { |
| if (element is List) { |
| helper(element); |
| } else { |
| result.add(element); |
| } |
| } |
| } |
| helper(nested); |
| return result; |
| } |
| |
| /// Asserts that [iter] contains only one element, and returns it. |
| only(Iterable iter) { |
| var iterator = iter.iterator(); |
| assert(iterator.hasNext); |
| var obj = iterator.next(); |
| assert(!iterator.hasNext); |
| return obj; |
| } |
| |
| /// Returns a set containing all elements in [minuend] that are not in |
| /// [subtrahend]. |
| Set setMinus(Collection minuend, Collection subtrahend) { |
| var minuendSet = new Set.from(minuend); |
| minuendSet.removeAll(subtrahend); |
| return minuendSet; |
| } |
| |
| /// Replace each instance of [matcher] in [source] with the return value of |
| /// [fn]. |
| String replace(String source, Pattern matcher, String fn(Match)) { |
| var buffer = new StringBuffer(); |
| var start = 0; |
| for (var match in matcher.allMatches(source)) { |
| buffer.add(source.substring(start, match.start)); |
| start = match.end; |
| buffer.add(fn(match)); |
| } |
| buffer.add(source.substring(start)); |
| return buffer.toString(); |
| } |
| |
| /// Returns whether or not [str] ends with [matcher]. |
| bool endsWithPattern(String str, Pattern matcher) { |
| for (var match in matcher.allMatches(str)) { |
| if (match.end == str.length) return true; |
| } |
| return false; |
| } |
| |
| /// Returns the hex-encoded sha1 hash of [source]. |
| String sha1(String source) => |
| CryptoUtils.bytesToHex(new SHA1().update(source.charCodes).digest()); |
| |
| /// Returns a [Future] that completes in [milliseconds]. |
| Future sleep(int milliseconds) { |
| var completer = new Completer(); |
| new Timer(milliseconds, completer.complete); |
| return completer.future; |
| } |
| |
| /// Configures [future] so that its result (success or exception) is passed on |
| /// to [completer]. |
| void chainToCompleter(Future future, Completer completer) { |
| future.handleException((e) { |
| completer.completeException(e, future.stackTrace); |
| return true; |
| }); |
| future.then(completer.complete); |
| } |
| |
| // TODO(nweiz): unify the following functions with the utility functions in |
| // pkg/http. |
| |
| /// Like [String.split], but only splits on the first occurrence of the pattern. |
| /// This will always return an array of two elements or fewer. |
| List<String> split1(String toSplit, String pattern) { |
| if (toSplit.isEmpty) return <String>[]; |
| |
| var index = toSplit.indexOf(pattern); |
| if (index == -1) return [toSplit]; |
| return [toSplit.substring(0, index), |
| toSplit.substring(index + pattern.length)]; |
| } |
| |
| /// Adds additional query parameters to [url], overwriting the original |
| /// parameters if a name conflict occurs. |
| Uri addQueryParameters(Uri url, Map<String, String> parameters) { |
| var queryMap = queryToMap(url.query); |
| mapAddAll(queryMap, parameters); |
| return url.resolve("?${mapToQuery(queryMap)}"); |
| } |
| |
| /// Convert a URL query string (or `application/x-www-form-urlencoded` body) |
| /// into a [Map] from parameter names to values. |
| Map<String, String> queryToMap(String queryList) { |
| var map = <String>{}; |
| for (var pair in queryList.split("&")) { |
| var split = split1(pair, "="); |
| if (split.isEmpty) continue; |
| var key = urlDecode(split[0]); |
| var value = split.length > 1 ? urlDecode(split[1]) : ""; |
| map[key] = value; |
| } |
| return map; |
| } |
| |
| /// Convert a [Map] from parameter names to values to a URL query string. |
| String mapToQuery(Map<String, String> map) { |
| var pairs = <List<String>>[]; |
| map.forEach((key, value) { |
| key = encodeUriComponent(key); |
| value = (value == null || value.isEmpty) ? null : encodeUriComponent(value); |
| pairs.add([key, value]); |
| }); |
| return Strings.join(pairs.map((pair) { |
| if (pair[1] == null) return pair[0]; |
| return "${pair[0]}=${pair[1]}"; |
| }), "&"); |
| } |
| |
| /// Add all key/value pairs from [source] to [destination], overwriting any |
| /// pre-existing values. |
| void mapAddAll(Map destination, Map source) => |
| source.forEach((key, value) => destination[key] = value); |
| |
| /// Decodes a URL-encoded string. Unlike [decodeUriComponent], this includes |
| /// replacing `+` with ` `. |
| String urlDecode(String encoded) => |
| decodeUriComponent(encoded.replaceAll("+", " ")); |