Clean up various ways we find paths in pub.

This makes it so that it's never necessary to pass in DART_SDK.

Review URL: https://codereview.chromium.org//14449004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@21914 260f80e4-7a28-3924-810f-c04153c831b5

lib/src/io.dart

@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 /// Helper functionality to make working with IO easier.
-library io;
+library pub.io;
 
 import 'dart:async';
 import 'dart:io';
@@ -253,22 +253,8 @@ void createPackageSymlink(String name, String target, String symlink,
 }
 
 /// Resolves [target] relative to the root directory of pub.
-String relativeToPub(String target) {
-  var scriptPath = new File(new Options().script).fullPathSync();
-
-  // Walk up until we hit the "internal(s)" directory. This lets us figure out
-  // where we are if this function is called from pub.dart, one of the tests, or
-  // from the SDK.
-  var internalDir = path.dirname(scriptPath);
-  while (path.basename(internalDir) != '_internal') {
-    if (path.basename(internalDir) == '') {
-      throw new Exception('Could not find path to pub.');
-    }
-    internalDir = path.dirname(internalDir);
-  }
-
-  return path.normalize(path.join(internalDir, 'pub', target));
-}
+String relativeToPub(String target) => path.normalize(path.join(
+    path.dirname(libraryPath('pub.io')), '..', '..', target));
 
 /// A line-by-line stream of standard input.
 final Stream<String> stdinLines = streamToLines(

lib/src/sdk.dart

@@ -28,8 +28,8 @@ String get rootDirectory {
     return dir;
   }
 
-  throw new Exception('DART_SDK environment variable not set, unable to find '
-      'the SDK.');
+  // Assume the Dart executable is always coming from the SDK.
+  return path.dirname(path.dirname(new Options().executable));
 }
 
 /// Gets the SDK's revision number formatted to be a semantic version.

lib/src/utils.dart

@@ -9,6 +9,7 @@ import 'dart:async';
 import 'dart:crypto';
 import 'dart:io';
 import 'dart:isolate';
+import 'dart:mirrors';
 import 'dart:uri';
 
 /// A pair of values.
@@ -360,6 +361,27 @@ Future awaitObject(object) {
   });
 }
 
+/// Returns the path to the library named [libraryName]. The library name must
+/// be globally unique, or the wrong library path may be returned.
+String libraryPath(String libraryName) =>
+  fileUriToPath(currentMirrorSystem().libraries[new Symbol(libraryName)].uri);
+
+/// Converts a `file:` [Uri] to a local path string.
+String fileUriToPath(Uri uri) {
+  if (uri.scheme != 'file') {
+    throw new ArgumentError("Uri $uri must have scheme 'file:'.");
+  }
+  if (Platform.operatingSystem != 'windows') return uri.path;
+  if (uri.path.startsWith("/")) {
+    // Drive-letter paths look like "file:///C:/path/to/file". The replaceFirst
+    // removes the extra initial slash.
+    return uri.path.replaceFirst("/", "").replaceAll("/", "\\");
+  } else {
+    // Network paths look like "file://hostname/path/to/file".
+    return "\\\\${uri.path.replaceAll("/", "\\")}";
+  }
+}
+
 /// An exception class for exceptions that are intended to be seen by the user.
 /// These exceptions won't have any debugging information printed when they're
 /// thrown.

test/real_version_test.dart

@@ -6,6 +6,8 @@ library pub_tests;
 
 import 'dart:io';
 
+import '../lib/src/sdk.dart' as sdk;
+
 import 'package:pathos/path.dart' as path;
 import 'package:scheduled_test/scheduled_process.dart';
 import 'package:scheduled_test/scheduled_test.dart';
@@ -28,9 +30,8 @@ main() {
   // the built SDK directory, and not the live pub code directly in the repo.
   integration('parse the real SDK "version" file', () {
     // Get the path to the pub binary in the SDK.
-    var dartPath = new Options().executable;
-    var pubPath = path.join(path.dirname(dartPath), "pub");
-    if (Platform.operatingSystem == "windows") pubPath = '$pubPath.bat';
+    var pubPath = path.join(sdk.rootDirectory, 'bin',
+        Platform.operatingSystem == "windows" ? "pub.bat" : "pub");
 
     var pub = new ScheduledProcess.start(pubPath, ['version']);
     expect(pub.nextLine(), completion(startsWith("Pub")));

test/test_pub.dart

@@ -272,12 +272,8 @@ void _integration(String description, void body(), [Function testFn]) {
 
 /// Get the path to the root "pub/test" directory containing the pub
 /// tests.
-String get testDirectory {
-  var dir = new Options().script;
-  while (path.basename(dir) != 'test') dir = path.dirname(dir);
-
-  return path.absolute(dir);
-}
+String get testDirectory =>
+  path.absolute(path.dirname(libraryPath('test_pub')));
 
 /// Schedules renaming (moving) the directory at [from] to [to], both of which
 /// are assumed to be relative to [sandboxDir].