Initial release.

lib/source_map_stack_trace.dart

+// Copyright (c) 2015, 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 source_map_stack_trace;
+
+import 'package:path/path.dart' as p;
+import 'package:source_maps/source_maps.dart';
+import 'package:stack_trace/stack_trace.dart';
+
+/// Convert [stackTrace], a stack trace generated by dart2js-compiled
+/// JavaScript, to a native-looking stack trace using [sourceMap].
+///
+/// [minified] indicates whether or not the dart2js code was minified. If it
+/// hasn't, this tries to clean up the stack frame member names.
+///
+/// [packageRoot] is the URI (usually a `file:` URI) for the package root that
+/// was used by dart2js. It can be a [String] or a [Uri]. If it's passed, stack
+/// frames from packages will use `package:` URLs.
+///
+/// [sdkRoot] is the URI (usually a `file:` URI) for the SDK containing dart2js.
+/// It can be a [String] or a [Uri]. If it's passed, stack frames from the SDK
+/// will have `dart:` URLs.
+StackTrace mapStackTrace(Mapping sourceMap, StackTrace stackTrace,
+    {bool minified: false, packageRoot, sdkRoot}) {
+  if (stackTrace is Chain) {
+    return new Chain(stackTrace.traces.map((trace) {
+      return mapStackTrace(trace, sourceMap,
+          minified: minified, packageRoot: packageRoot, sdkRoot: sdkRoot);
+    }));
+  }
+
+  if (packageRoot != null && packageRoot is! String && packageRoot is! Uri) {
+    throw new ArgumentError(
+        'packageRoot must be a String or a Uri, was "$packageRoot".');
+  }
+
+  if (sdkRoot != null && sdkRoot is! String && sdkRoot is! Uri) {
+    throw new ArgumentError(
+        'sdkRoot must be a String or a Uri, was "$sdkRoot".');
+  }
+
+  packageRoot = packageRoot == null ? null : packageRoot.toString();
+  var sdkLib = sdkRoot == null ? null : "$sdkRoot/lib";
+
+  var trace = new Trace.from(stackTrace);
+  return new Trace(trace.frames.map((frame) {
+    // If there's no line information, there's no way to translate this frame.
+    // We could return it as-is, but these lines are usually not useful anyways.
+    if (frame.line == null) return null;
+
+    // If there's no column, try using the first column of the line.
+    var column = frame.column == null ? 0 : frame.column;
+    var span = sourceMap.spanFor(frame.line, column);
+
+    // If we can't find a source span, ignore the frame. It's probably something
+    // internal that the user doesn't care about.
+    if (span == null) return null;
+
+    var sourceUrl = span.sourceUrl.toString();
+    if (packageRoot != null && p.url.isWithin(packageRoot, sourceUrl)) {
+      sourceUrl = "package:" +
+          p.url.relative(sourceUrl, from: packageRoot);
+    } else if (sdkRoot != null && p.url.isWithin(sdkLib, sourceUrl)) {
+      sourceUrl = "dart:" + p.url.relative(sourceUrl, from: sdkLib);
+    }
+
+    return new Frame(
+        Uri.parse(sourceUrl),
+        span.start.line + 1,
+        span.start.column + 1,
+        // If the dart2js output is minified, there's no use trying to prettify
+        // its member names. Use the span's identifier if available, otherwise
+        // use the minified member name.
+        minified
+            ? (span.isIdentifier ? span.text : frame.member)
+            : _prettifyMember(frame.member));
+  }).where((frame) => frame != null));
+}
+
+/// Reformats a JS member name to make it look more Dart-like.
+String _prettifyMember(String member) {
+  return member
+      // Get rid of the noise that Firefox sometimes adds.
+      .replaceAll(new RegExp(r"/?<$"), "")
+      // Get rid of arity indicators.
+      .replaceAll(new RegExp(r"\$\d+$"), "")
+      // Convert closures to <fn>.
+      .replaceAllMapped(new RegExp(r"(_+)closure\d*\.call$"),
+          // The number of underscores before "closure" indicates how nested it
+          // is.
+          (match) => ".<fn>" * match[1].length)
+      // Get rid of explicitly-generated calls.
+      .replaceAll(new RegExp(r"\.call$"), "")
+      // Get rid of the top-level method prefix.
+      .replaceAll(new RegExp(r"^dart\."), "")
+      // Get rid of library namespaces.
+      .replaceAll(new RegExp(r"[a-zA-Z_0-9]+\$"), "")
+      // Get rid of the static method prefix. The class name also exists in the
+      // invocation, so we're not getting rid of any information.
+      .replaceAll(new RegExp(r"^[a-zA-Z_0-9]+.static."), "")
+      // Convert underscores after identifiers to dots. This runs the risk of
+      // incorrectly converting members that contain underscores, but those are
+      // contrary to the style guide anyway.
+      .replaceAllMapped(new RegExp(r"([a-zA-Z0-9]+)_"),
+          (match) => match[1] + ".");
+}