Start implementing pub object model. Rudimentary package cache class, and a simple pub command to l…

utils/pub/io.dart

+// 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.
+
+/**
+ * Helper functionality to make working with IO easier.
+ */
+#library('pub_io');
+
+#import('dart:io');
+
+#import('../lib/file_system.dart', prefix: 'fs');
+
+/**
+ * Joins a number of path string parts into a single path. Handles
+ * platform-specific path separators. Parts can be [String], [Directory], or
+ * [File] objects.
+ */
+String join(part1, [part2, part3, part4]) {
+  final parts = _getPath(part1).split('/');
+
+  for (final part in [part2, part3, part4]) {
+    if (part == null) continue;
+
+    for (final piece in _getPath(part).split('/')) {
+      if (piece == '..' && parts.length > 0 &&

[nweiz, 2012/04/17 20:08:46]

Unless you have a good reason to try and clean up the paths, I'd just let the
underlying APIs sort out ".." and friends. It just adds needless complexity
here.

[Bob Nystrom, 2012/04/18 18:09:18]

This is mostly copied from file_system and I have run into cases where the
underlying API barfs if it gets a path that contains ../ for some reason. I
agree this is a little hairy, but I like that the hair is at least contained
here.

+          parts.last() != '.' && parts.last() != '..') {
+        parts.removeLast();
+      } else if (piece != '') {
+        if (parts.length > 0 && parts.last() == '.') {
+          parts.removeLast();
+        }
+        parts.add(piece);
+      }
+    }
+  }
+
+  return Strings.join(parts, new Platform().pathSeparator());
+}
+
+/**
+ * Gets the basename, the file name without any leading directory path, for
+ * [file], which can either be a [String], [File], or [Directory].
+ */
+String basename(file) {
+  return fs.basename(_getPath(file));
+}
+
+/**
+ * Reads the contents of the text file [file], which can either be a [String] or
+ * a [File].
+ */
+Future<String> readTextFile(file) {
+  file = new File(_getPath(file));
+  final completer = new Completer<String>();
+  file.onError = (error) => completer.completeException(error);
+  file.readAsText(Encoding.UTF_8, (text) {
+    completer.complete(text);

[nweiz, 2012/04/17 20:08:46]

I don't understand your heuristic for when you use "() =>" and when not to.

[Bob Nystrom, 2012/04/18 18:09:18]

It was apparently based on astrology. Made less crazy.

I think the original process was:
1. Try to use () =>
2. But if there's a nearby lambda (like onError and onFile next to each other)
that can't (because it contains a statement) make them all use () {}.
Somehow this got added:
3. Roll 2d6. If < 8, ignore rule 2.

+  });
+
+  return completer.future;
+}
+
+/**
+ * Creates [file] (which can either be a [String] or a [File]), and writes
+ * [contents] to it. Completes when the file is written and closed.
+ */
+Future<File> writeTextFile(file, String contents) {
+  file = new File(_getPath(file));
+  final completer = new Completer<File>();
+  file.onError = (error) => completer.completeException(error);
+  file.open(FileMode.WRITE, (opened) {
+    opened.onError = (error) => completer.completeException(error);
+    opened.onNoPendingWrites = () {
+      opened.close(() {
+        completer.complete(file);
+      });
+    };
+    opened.writeString(contents);
+  });
+
+  return completer.future;
+}
+
+/**
+ * Creates a directory [dir]. Returns a [Future] that completes when the
+ * directory is created.
+ */
+Future<Directory> createDir(dir) {
+  final completer = new Completer<Directory>();
+  dir = _getDirectory(dir);
+  dir.onError = (error) => completer.completeException(error);
+  dir.create(() {
+    completer.complete(dir);
+  });
+
+  return completer.future;
+}
+
+/**
+ * Creates a temp directory whose name will be based on [dir] with a unique
+ * suffix appended to it. Returns a [Future] that completes when the directory
+ * is created.
+ */
+Future<Directory> createTempDir(dir) {
+  final completer = new Completer<Directory>();
+  dir = _getDirectory(dir);
+  dir.onError = (error) => completer.completeException(error);
+  dir.createTemp(() {
+    completer.complete(dir);
+  });
+
+  return completer.future;
+}
+
+/**
+ * Asynchronously recursively deletes [dir], which can be a [String] or a
+ * [Directory]. Returns a [Future] that completes when the deletion is done.
+ */
+Future<Directory> deleteDir(dir) {
+  final completer = new Completer<Directory>();
+  dir = _getDirectory(dir);
+  dir.onError = (error) => completer.completeException(error);
+  dir.deleteRecursively(() {
+    completer.complete(dir);
+  });
+
+  return completer.future;
+}
+
+/**
+ * Asynchronously lists the contents of [dir], which can be a [String] directory
+ * path or a [Directory]. If [recursive] is `true`, lists subdirectory contents
+ * (defaults to `false`). If [includeSpecialFiles] is `true`, includes "hidden"
+ * files like `.DS_Store` (defaults to `false`).
+ */
+Future<List<String>> listDir(dir,
+    [bool recursive = false, bool includeSpecialFiles = false]) {
+  final completer = new Completer<List<String>>();
+  final contents = <String>[];
+
+  dir = _getDirectory(dir);
+
+  dir.onDone  = (done) {

[nweiz, 2012/04/17 20:08:46]

nit: extra space after "Done".

What are the semantics of the "done" parameter?

[Bob Nystrom, 2012/04/18 18:09:18]

Done.
I think onDone will always be called and it will be passed false if onError was
called beforehand? I'm not sure.

+    if (done) completer.complete(contents);
+  };
+
+  dir.onError = (error) {
+    completer.completeException(error);
+  };
+
+  dir.onDir = (file) {
+    contents.add(file);
+  };
+
+  dir.onFile = (file) {
+    if (!includeSpecialFiles) {
+      if (basename(file) == '.DS_Store') return;

[nweiz, 2012/04/17 20:08:46]

The documentation implies that this is going to filter out all hidden files, not
just a pre-defined blacklist.

[Bob Nystrom, 2012/04/18 18:09:18]

Clarified docs.

+    }
+
+    contents.add(file);
+  };
+
+  dir.list(recursive: recursive);
+
+  return completer.future;
+}
+
+/**
+ * Spawns and runs the process located at [executable], passing in [args].
+ * Returns a [Future] that will complete the results of the process after it
+ * has ended.
+ */
+Future<ProcessResult> runProcess(String executable, List<String> args) {
+  var exitCode;

[nweiz, 2012/04/17 20:08:46]

Explicitly type this because it's not being initialized here

[Bob Nystrom, 2012/04/18 18:09:18]

Done.

+  var error;

[nweiz, 2012/04/17 20:08:46]

Unused variable

[Bob Nystrom, 2012/04/18 18:09:18]

Done.

+
+  final process = new Process.start(executable, args);
+
+  final outStream = new StringInputStream(process.stdout);
+  final processStdout = <String>[];
+
+  final errStream = new StringInputStream(process.stderr);
+  final processStderr = <String>[];
+  bool processDone = false;

[nweiz, 2012/04/17 20:08:46]

var or final

[Bob Nystrom, 2012/04/18 18:09:18]

Unused.

+
+  final completer = new Completer<ProcessResult>();
+
+  checkComplete() {
+    // Wait until the process is done and its output streams are closed.
+    if (!outStream.closed) return;
+    if (!errStream.closed) return;
+    if (exitCode == null) return;
+
+    completer.complete(new ProcessResult(
+        processStdout, processStderr, exitCode));
+  }
+
+  outStream.onLine = () {
+    processStdout.add(outStream.readLine());
+  };
+
+  outStream.onClosed = checkComplete;
+  outStream.onError = (error) => completer.completeException(error);
+
+  errStream.onLine = () {
+    processStderr.add(errStream.readLine());
+  };
+
+  errStream.onClosed = checkComplete;
+  errStream.onError = (error) => completer.completeException(error);
+
+  process.onExit = (actualExitCode) {
+    exitCode = actualExitCode;
+    checkComplete();
+  };
+
+  process.onError = (error) => completer.completeException(error);
+
+  return completer.future;
+}
+
+/**
+ * Contains the results of invoking a [Process] and waiting for it to complete.
+ */
+class ProcessResult {
+  final List<String> stdout;
+  final List<String> stderr;
+  final int exitCode;
+
+  const ProcessResult(this.stdout, this.stderr, this.exitCode);
+}
+
+/**
+ * Gets the path string for [entry], which can either already be a path string,
+ * or be a [File] or [Directory]. Allows working generically with "file-like"
+ * objects.
+ */
+String _getPath(entry) {
+  if (entry is String) return entry;
+  if (entry is File) return entry.name;
+  if (entry is Directory) return entry.path;
+  throw 'Entry $entry is not a supported type.';
+}
+
+/**
+ * Gets a [Directory] for [entry], which can either already be one, or be a
+ * [String].
+ */
+Directory _getDirectory(entry) {
+  if (entry is Directory) return entry;
+  return new Directory(entry);
+}