Add a "pub global run" command.

sdk/lib/_internal/pub/lib/src/executable.dart

Index: sdk/lib/_internal/pub/lib/src/executable.dart
diff --git a/sdk/lib/_internal/pub/lib/src/executable.dart b/sdk/lib/_internal/pub/lib/src/executable.dart
new file mode 100644
index 0000000000000000000000000000000000000000..9180558a9815e6b6943d364602ec4db81707560c
--- /dev/null
+++ b/sdk/lib/_internal/pub/lib/src/executable.dart
@@ -0,0 +1,128 @@
+// Copyright (c) 2014, 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.
+
+library pub.executable;
+
+import 'dart:async';
+import 'dart:io';
+
+import 'package:barback/barback.dart';
+import 'package:path/path.dart' as p;
+import 'package:stack_trace/stack_trace.dart';
+
+import 'barback/asset_environment.dart';
+import 'barback/barback_server.dart';
+import 'entrypoint.dart';
+import 'exit_codes.dart' as exit_codes;
+import 'log.dart' as log;
+import 'utils.dart';
+
+/// Runs [executable] from [package] reachable from [entrypoint].
+///
+/// The [executable] is a reference to an "executable", a relative Dart file

[nweiz, 2014/07/02 00:12:02]

"The" here is confusing, since we generally don't use the definite article for
parameters in general and you already referred to [executable] without it in the
previous sentence. I know you don't like starting paragraphs with variable
names, but I don't think this is the right way to avoid that here.

[Bob Nystrom, 2014/07/02 18:00:52]

Reworded.

+/// path using native path separators without a trailing ".dart" extension.
+/// It is contained within [package], which should either be the entrypoint
+/// package, or an immediate dependency of it.

[nweiz, 2014/07/02 00:12:02]

Nix this comma.

[Bob Nystrom, 2014/07/02 18:00:53]

Done.

+///
+/// Arguments from [args] will be passed to the spawned Dart application.
+///
+/// Returns the exit code of the spawned app.
+Future<int> runExecutable(Entrypoint entrypoint, String package,
+    String executable, Iterable<String> args) {
+  // If the command has a path separator, then it's a path relative to the
+  // root of the package. Otherwise, it's implicitly understood to be in
+  // "bin".
+  var rootDir = "bin";
+  var parts = p.split(executable);
+  if (parts.length > 1) {
+    if (package != entrypoint.root.name) {
+      usageError("Can not run an executable in a subdirectory of a "

[nweiz, 2014/07/02 00:12:02]

"Can not" -> "Cannot"

[Bob Nystrom, 2014/07/02 18:00:52]

Done.

+          "dependency.");
+    }
+
+    rootDir = parts.first;
+  } else {
+    executable = p.join("bin", executable);
+  }
+
+  // Unless the user overrides the verbosity, we want to filter out the
+  // normal pub output shown while loading the environment.
+  if (log.verbosity == log.Verbosity.NORMAL) {
+    log.verbosity = log.Verbosity.WARNING;
+  }
+
+  var environment;
+  return AssetEnvironment.create(entrypoint, BarbackMode.RELEASE,
+      WatcherType.NONE, useDart2JS: false).then((_environment) {
+    environment = _environment;
+
+    // Show in-progress errors, but not results. Those get handled
+    // implicitly by getAllAssets().

[nweiz, 2014/07/02 00:12:02]

This comment doesn't apply here.

[Bob Nystrom, 2014/07/02 18:00:53]

Done.

+    environment.barback.errors.listen((error) {
+      log.error(log.red("Build error:\n$error"));
+    });
+
+    if (package == entrypoint.root.name) {
+      // Serve the entire root-most directory containing the entrypoint. That
+      // ensures that, for example, things like `import '../../utils.dart';`
+      // will work from within some deeply nested script.
+      return environment.serveDirectory(rootDir);
+    } else {

[nweiz, 2014/07/02 00:12:02]

Remove this; you can just short-circuit here.

[Bob Nystrom, 2014/07/02 18:00:52]

Done.

+      // Make sure the dependency exists.
+      var dep = entrypoint.root.immediateDependencies.firstWhere(
+              (dep) => dep.name == package, orElse: () => null);
+      if (dep == null) {
+        if (environment.graph.packages.containsKey(package)) {
+          dataError('Package "$package" is not an immediate dependency.\n'
+          'Cannot run executables in transitive dependencies.');
+        } else {
+          dataError('Could not find package "$package". Did you forget to '
+          'add a dependency?');
+        }
+      }
+
+      // For other packages, always use the "bin" directory.
+      return environment.servePackageBinDirectory(package);
+    }
+  }).then((server) {
+    // Try to make sure the entrypoint script exists (or is generated) before
+    // we spawn the process to run it.
+    var assetPath = "${p.url.joinAll(p.split(executable))}.dart";
+    var id = new AssetId(server.package, assetPath);
+    return environment.barback.getAssetById(id).then((_) {
+      var vmArgs = [];
+
+      // Run in checked mode.
+      // TODO(rnystrom): Make this configurable.
+      vmArgs.add("--checked");
+
+      // Get the URL of the executable, relative to the server's root directory.
+      var relativePath = p.url.relative(assetPath,
+      from: p.url.joinAll(p.split(server.rootDirectory)));

[nweiz, 2014/07/02 00:12:02]

Indent this line.

[Bob Nystrom, 2014/07/02 18:00:53]

Done.

+      vmArgs.add(server.url.resolve(relativePath).toString());
+      vmArgs.addAll(args);
+
+      return Process.start(Platform.executable, vmArgs).then((process) {
+        // Note: we're not using process.std___.pipe(std___) here because
+        // that prevents pub from also writing to the output streams.
+        process.stderr.listen(stderr.add);
+        process.stdout.listen(stdout.add);
+        stdin.listen(process.stdin.add);
+
+        return process.exitCode;
+      });
+    }).catchError((error, stackTrace) {
+      if (error is! AssetNotFoundException) throw error;
+
+      var message = "Could not find ${log.bold(executable + ".dart")}";
+      if (package != entrypoint.root.name) {
+        message += " in package ${log.bold(server.package)}";
+      }
+
+      log.error("$message.");
+      log.fine(new Chain.forTrace(stackTrace));
+      return exit_codes.NO_INPUT;
+    });
+  });
+}