Revert "Use native async/await support in pub."

sdk/lib/_internal/pub/bin/async_compile.dart

+// 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.
+
+import 'dart:io';
+
+import 'package:args/args.dart';
+import 'package:analyzer/src/services/formatter_impl.dart';
+import 'package:async_await/async_await.dart' as async_await;
+import 'package:stack_trace/stack_trace.dart';
+import 'package:path/path.dart' as p;
+
+/// The path to pub's root directory (sdk/lib/_internal/pub) in the Dart repo.
+///
+/// This assumes this script is itself being run from within the repo.
+final sourceDir = p.dirname(p.dirname(p.fromUri(Platform.script)));
+
+/// The [sourceDir] as a URL, for use in import strings.
+final sourceUrl = p.toUri(sourceDir).toString();
+
+/// The directory that compiler output should be written to.
+String generatedDir;
+
+/// `true` if any file failed to compile.
+bool hadFailure = false;
+
+bool verbose = false;
+
+/// Prefix for imports in pub that import dart2js libraries.
+final _compilerPattern = new RegExp(r"import '(\.\./)+compiler");
+
+/// Matches the Git commit hash of the compiler stored in the README.md file.
+///
+/// This is used both to find the current commit and replace it with the new
+/// one.
+final _commitPattern = new RegExp(r"[a-f0-9]{40}");
+
+/// The template for the README that's added to the generated source.
+///
+/// This is used to store the current commit of the async_await compiler.
+const _README = """
+Pub is currently dogfooding the new Dart async/await syntax. Since the Dart VM
+doesn't natively support it yet, we are using the [async-await][] compiler
+package.
+
+[async-await]: https://github.com/dart-lang/async_await
+
+We run that to compile pub-using-await from sdk/lib/_internal/pub down to
+vanilla Dart code which is what you see here. To interoperate more easily with
+the rest of the repositry, we check in that generated code.
+
+When bug #104 is fixed, we can remove this entirely.
+
+The code here was compiled using the async-await compiler at commit:
+
+    <<COMMIT>>
+
+(Note: this file is also parsed by a tool to update the above commit, so be
+careful not to reformat it.)
+""";
+
+/// This runs the async/await compiler on all of the pub source code.
+///
+/// It reads from the repo and writes the compiled output into the given build
+/// directory (using the same file names and relative layout). Does not
+/// compile files that haven't changed since the last time they were compiled.
+// TODO(rnystrom): Remove this when #104 is fixed.
+void main(List<String> arguments) {
+  var parser = new ArgParser(allowTrailingOptions: true);
+
+  parser.addFlag("verbose", callback: (value) => verbose = value);
+
+  var force = false;
+  parser.addFlag("force", callback: (value) => force = value);
+
+  var buildDir;
+  parser.addOption("snapshot-build-dir", callback: (value) => buildDir = value);
+
+  try {
+    var rest = parser.parse(arguments).rest;
+    if (rest.isEmpty) {
+      throw new FormatException('Missing generated directory.');
+    } else if (rest.length > 1) {
+      throw new FormatException(
+          'Unexpected arguments: ${rest.skip(1).join(" ")}.');
+    }
+
+    generatedDir = rest.first;
+  } on FormatException catch(ex) {
+    stderr.writeln(ex);
+    stderr.writeln();
+    stderr.writeln(
+        "Usage: dart async_compile.dart [--verbose] [--force] "
+        "[--snapshot-build-dir <dir>] <generated dir>");
+    exit(64);
+  }
+
+  // See what version (i.e. Git commit) of the async-await compiler we
+  // currently have. If this is different from the version that was used to
+  // compile the sources, recompile everything.
+  var currentCommit = _getCurrentCommit();
+
+  var readmePath = p.join(generatedDir, "README.md");
+  var lastCommit;
+  try {
+    var readme = new File(readmePath).readAsStringSync();
+    var match = _commitPattern.firstMatch(readme);
+    if (match == null) {
+      stderr.writeln("Could not find compiler commit hash in README.md.");
+      exit(1);
+    }
+
+    lastCommit = match[0];
+  } on IOException catch (error, stackTrace) {
+    if (verbose) {
+      stderr.writeln("Failed to load $readmePath: $error\n"
+          "${new Trace.from(stackTrace)}");
+    }
+  }
+
+  var numFiles = 0;
+  var numCompiled = 0;
+
+  // Compile any modified or missing files.
+  var sources = new Set();
+  for (var entry in new Directory(sourceDir).listSync(recursive: true)) {
+    if (p.extension(entry.path) != ".dart") continue;
+
+    numFiles++;
+    var relative = p.relative(entry.path, from: sourceDir);
+    sources.add(relative);
+
+    var sourceFile = entry as File;
+    var destPath = p.join(generatedDir, relative);
+    var destFile = new File(destPath);
+    if (force ||
+        currentCommit != lastCommit ||
+        !destFile.existsSync() ||
+        entry.lastModifiedSync().isAfter(destFile.lastModifiedSync())) {
+      _compile(sourceFile.path, sourceFile.readAsStringSync(), destPath);
+      numCompiled++;
+      if (verbose) print("Compiled $relative");
+    }
+  }
+
+  // Delete any previously compiled files whose source no longer exists.
+  for (var entry in new Directory(generatedDir).listSync(recursive: true)) {
+    if (p.extension(entry.path) != ".dart") continue;
+
+    var relative = p.relative(entry.path, from: generatedDir);
+
+    if (!sources.contains(relative)) {
+      _deleteFile(entry.path);
+      if (verbose) print("Deleted  $relative");
+    }
+  }
+
+  // Update the README.
+  if (currentCommit != lastCommit) {
+    _writeFile(readmePath, _README.replaceAll("<<COMMIT>>", currentCommit));
+    if (verbose) print("Updated README.md");
+  }
+
+  if (numCompiled > 0 && buildDir != null) _generateSnapshot(buildDir);
+
+  if (verbose) print("Compiled $numCompiled out of $numFiles files");
+
+  if (hadFailure) exit(1);
+}
+
+String _getCurrentCommit() {
+  var command = "git";
+  var args = ["rev-parse", "HEAD"];
+
+  // Spawning a process on Windows will not look for the executable in the
+  // system path so spawn git through a shell to find it.
+  if (Platform.operatingSystem == "windows") {
+    command = "cmd";
+    args = ["/c", "git"]..addAll(args);
+  }
+
+  var result = Process.runSync(command, args, workingDirectory:
+      p.join(sourceDir, "../../../../third_party/pkg/async_await"));
+  if (result.exitCode != 0) {
+    stderr.writeln("Could not get Git revision of async_await compiler.");
+    exit(1);
+  }
+
+  return result.stdout.trim();
+}
+
+void _compile(String sourcePath, String source, String destPath) {
+  var destDir = new Directory(p.dirname(destPath));
+  destDir.createSync(recursive: true);
+
+  source = _translateAsyncAwait(sourcePath, source);
+  if (source != null) source = _fixDart2jsImports(sourcePath, source, destPath);
+
+  if (source == null) {
+    // If the async compile fails, delete the file so that we don't try to
+    // run the stale previous output and so that we try to recompile it later.
+    _deleteFile(destPath);
+  } else {
+    _writeFile(destPath, source);
+  }
+}
+
+/// Runs the async/await compiler on [source].
+///
+/// Returns the translated Dart code or `null` if the compiler failed.
+String _translateAsyncAwait(String sourcePath, String source) {
+  if (p.isWithin(p.join(sourceDir, "asset"), sourcePath)) {
+    // Don't run the async compiler on the special "asset" source files. These
+    // have preprocessor comments that get discarded by the compiler.
+    return source;
+  }
+
+  try {
+    source = async_await.compile(source);
+
+    // Reformat the result since the compiler ditches all whitespace.
+    // TODO(rnystrom): Remove when this is fixed:
+    // https://github.com/dart-lang/async_await/issues/12
+    var result = new CodeFormatter().format(CodeKind.COMPILATION_UNIT, source);
+    return result.source;
+  } catch (ex) {
+    stderr.writeln("Async compile failed on $sourcePath:\n$ex");
+    hadFailure = true;
+    return null;
+  }
+}
+
+/// Fix relative imports to dart2js libraries.
+///
+/// Pub imports dart2js using relative imports that reach outside of pub's
+/// source tree. Since the build directory is in a different location, we need
+/// to fix those to be valid relative imports from the build directory.
+String _fixDart2jsImports(String sourcePath, String source, String destPath) {
+  var compilerDir = p.url.join(sourceUrl, "../compiler");
+  var relative = p.url.relative(compilerDir,
+      from: p.url.dirname(p.toUri(destPath).toString()));
+  return source.replaceAll(_compilerPattern, "import '$relative");
+}
+
+/// Regenerate the pub snapshot from the async/await-compiled output. We do
+/// this here since the tests need it and it's faster than doing a full SDK
+/// build.
+void _generateSnapshot(String buildDir) {
+  buildDir = p.normalize(buildDir);
+  new Directory(buildDir).createSync(recursive: true);
+
+  var entrypoint = p.join(generatedDir, 'bin/pub.dart');
+  var packageRoot = p.join(buildDir, 'packages');
+  var snapshot = p.join(buildDir, 'dart-sdk/bin/snapshots/pub.dart.snapshot');
+
+  var result = Process.runSync(Platform.executable, [
+    "--package-root=$packageRoot",
+    "--snapshot=$snapshot",
+    entrypoint
+  ]);
+
+  if (result.exitCode != 0) {
+    stderr.writeln("Failed to generate snapshot:");
+    if (result.stderr.trim().isNotEmpty) stderr.writeln(result.stderr);
+    if (result.stdout.trim().isNotEmpty) stderr.writeln(result.stdout);
+    exit(result.exitCode);
+  }
+
+  if (verbose) print("Created pub snapshot");
+}
+
+/// Deletes the file at [path], ignoring any IO errors that occur.
+///
+/// This swallows errors to accommodate multiple compilers running concurrently.
+/// Since they will produce the same output anyway, a failure of one is fine.
+void _deleteFile(String path) {
+  try {
+    new File(path).deleteSync();
+  } on IOException catch (ex) {
+    // Do nothing.
+  }
+}
+
+/// Writes [contents] to [path], ignoring any IO errors that occur.
+///
+/// This swallows errors to accommodate multiple compilers running concurrently.
+/// Since they will produce the same output anyway, a failure of one is fine.
+void _writeFile(String path, String contents) {
+  try {
+    new File(path).writeAsStringSync(contents);
+  } on IOException catch (ex) {
+    // Do nothing.
+  }
+}