Support both new and old style package layouts.

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('io');
 
 #import('dart:io');
@@ skipping 262 matching lines @@
     args = ['/c', 'mklink', '/j', to, from];
   }
 
   return runProcess(command, args).transform((result) {
     // TODO(rnystrom): Check exit code and output?
     return new File(to);
   });
 }
 
 /**
+ * Creates a new symlink that creates an alias from the package [from] to [to],
+ * both of which can be a [String], [File], or [Directory]. Returns a [Future]
+ * which completes to the symlink file (i.e. [to]).
+ *
+ * Unlike [createSymlink], this has heuristics to detect if [from] is using
+ * the old or new style of package layout. If it's using the new style, then
+ * it will create a symlink to the "lib" directory contained inside that
+ * package directory. Otherwise, it just symlinks to the package directory
+ * itself.
+ */
+// TODO(rnystrom): Remove this when old style packages are no longer supported.
+// See: http://code.google.com/p/dart/issues/detail?id=4964.
+Future<File> createPackageSymlink(String name, from, to,

[nweiz, 2012/09/11 21:07:47]

Can't you infer the name from "from"?

[Bob Nystrom, 2012/09/11 21:39:01]

I could, but every callsite knew the name so I figured it was simplest just to
pass it in.

+    [bool isSelfLink = false]) {
+  // If from contains any Dart files at the top level (aside from build.dart)
+  // we assume that means it's an old style package.
+  return listDir(from).chain((contents) {
+    var isOldStyle = contents.some(
+        (file) => file.endsWith('.dart') && basename(file) != 'build.dart');
+
+    if (isOldStyle) {
+      if (isSelfLink) {
+        printError('Warning: Package "$name" is using a deprecated layout.');
+        printError('See http://www.dartlang.org/docs/pub-package-manager/'
+            'package-layout.html for details.');
+
+        // Do not create self-links on old style packages.
+        return new Future.immediate(to);
+      } else {
+        return createSymlink(from, to);
+      }
+    }
+
+    // It's a new style package, so symlink to the 'lib' directory. But only
+    // if the package actually *has* one. Otherwise, we won't create a
+    // symlink at all.
+    from = join(from, 'lib');
+    return dirExists(from).chain((exists) {
+      if (exists) {
+        return createSymlink(from, to);
+      } else {
+        printError('Warning: Package "$name" does not have a "lib" directory.');
+        return new Future.immediate(to);
+      }
+    });
+  });
+}
+
+/**
  * Given [entry] which may be a [String], [File], or [Directory] relative to
  * the current working directory, returns its full canonicalized path.
  */
 // TODO(rnystrom): Should this be async?
 String getFullPath(entry) => new File(_getPath(entry)).fullPathSync();
 
 // TODO(nweiz): make this configurable
 /**
  * The amount of time in milliseconds to allow HTTP requests before assuming
  * they've failed.
@@ skipping 281 matching lines @@
   return new Directory(entry);
 }
 
 /**
  * Gets a [Uri] for [uri], which can either already be one, or be a [String].
  */
 Uri _getUri(uri) {
   if (uri is Uri) return uri;
   return new Uri.fromString(uri);
 }