lib/src/trace.dart - stack_trace - Git at Google

 // Copyright (c) 2013, 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:math' as math;

 import 'chain.dart';
 import 'frame.dart';
 import 'lazy_trace.dart';
 import 'unparsed_frame.dart';
 import 'utils.dart';
 import 'vm_trace.dart';

 final _terseRegExp = new RegExp(r"(-patch)?([/\\].*)?$");

 /// A RegExp to match V8's stack traces.
 ///
 /// V8's traces start with a line that's either just "Error" or else is a
 /// description of the exception that occurred. That description can be multiple
 /// lines, so we just look for any line other than the first that begins with
 /// three or four spaces and "at".
 final _v8Trace = new RegExp(r"\n    ?at ");

 /// A RegExp to match indidual lines of V8's stack traces.
 ///
 /// This is intended to filter out the leading exception details of the trace
 /// though it is possible for the message to match this as well.
 final _v8TraceLine = new RegExp(r"    ?at ");

 /// A RegExp to match Firefox and Safari's stack traces.
 ///
 /// Firefox and Safari have very similar stack trace formats, so we use the same
 /// logic for parsing them.
 ///
 /// Firefox's trace frames start with the name of the function in which the
 /// error occurred, possibly including its parameters inside `()`. For example,
 /// `.VW.call$0("arg")@http://pub.dartlang.org/stuff.dart.js:560`.
 ///
 /// Safari traces occasionally don't include the initial method name followed by
 /// "@", and they always have both the line and column number (or just a
 /// trailing colon if no column number is available). They can also contain
 /// empty lines or lines consisting only of `[native code]`.
 final _firefoxSafariTrace = new RegExp(
     r"^"
     r"(" // Member description. Not present in some Safari frames.
       r"([.0-9A-Za-z_$/<]|\(.*\))*" // Member name and arguments.
       r"@"
     r")?"
     r"[^\s]*" // Frame URL.
     r":\d*" // Line or column number. Some older frames only have a line number.
     r"$", multiLine: true);

 /// A RegExp to match this package's stack traces.
 final _friendlyTrace = new RegExp(r"^[^\s<][^\s]*( \d+(:\d+)?)?[ \t]+[^\s]+$",
     multiLine: true);

 /// A stack trace, comprised of a list of stack frames.
 class Trace implements StackTrace {
   /// The stack frames that comprise this stack trace.
   final List<Frame> frames;

   /// Returns a human-readable representation of [stackTrace]. If [terse] is
   /// set, this folds together multiple stack frames from the Dart core
   /// libraries, so that only the core library method directly called from user
   /// code is visible (see [Trace.terse]).
   static String format(StackTrace stackTrace, {bool terse: true}) {
     var trace = new Trace.from(stackTrace);
     if (terse) trace = trace.terse;
     return trace.toString();
   }

   /// Returns the current stack trace.
   ///
   /// By default, the first frame of this trace will be the line where
   /// [Trace.current] is called. If [level] is passed, the trace will start that
   /// many frames up instead.
   factory Trace.current([int level=0]) {
     if (level < 0) {
       throw new ArgumentError("Argument [level] must be greater than or equal "
           "to 0.");
     }

     var trace = new Trace.from(StackTrace.current);
     return new LazyTrace(() {
       // JS includes a frame for the call to StackTrace.current, but the VM
       // doesn't, so we skip an extra frame in a JS context.
       return new Trace(trace.frames.skip(level + (inJS ? 2 : 1)));
     });
   }

   /// Returns a new stack trace containing the same data as [trace].
   ///
   /// If [trace] is a native [StackTrace], its data will be parsed out; if it's
   /// a [Trace], it will be returned as-is.
   factory Trace.from(StackTrace trace) {
     // Normally explicitly validating null arguments is bad Dart style, but here
     // the natural failure will only occur when the LazyTrace is materialized,
     // and we want to provide an error that's more local to the actual problem.
     if (trace == null) {
       throw new ArgumentError("Cannot create a Trace from null.");
     }

     if (trace is Trace) return trace;
     if (trace is Chain) return trace.toTrace();
     return new LazyTrace(() => new Trace.parse(trace.toString()));
   }

   /// Parses a string representation of a stack trace.
   ///
   /// [trace] should be formatted in the same way as a Dart VM or browser stack
   /// trace. If it's formatted as a stack chain, this will return the equivalent
   /// of [Chain.toTrace].
   factory Trace.parse(String trace) {
     try {
       if (trace.isEmpty) return new Trace(<Frame>[]);
       if (trace.contains(_v8Trace)) return new Trace.parseV8(trace);
       if (trace.contains("\tat ")) return new Trace.parseJSCore(trace);
       if (trace.contains(_firefoxSafariTrace)) {
         return new Trace.parseFirefox(trace);
       }
       if (trace.contains(chainGap)) return new Chain.parse(trace).toTrace();
       if (trace.contains(_friendlyTrace)) {
         return new Trace.parseFriendly(trace);
       }

       // Default to parsing the stack trace as a VM trace. This is also hit on
       // IE and Safari, where the stack trace is just an empty string (issue
       // 11257).
       return new Trace.parseVM(trace);
     } on FormatException catch (error) {
       throw new FormatException('${error.message}\nStack trace:\n$trace');
     }
   }

   /// Parses a string representation of a Dart VM stack trace.
   Trace.parseVM(String trace)
       : this(_parseVM(trace));

   static List<Frame> _parseVM(String trace) {
     // Ignore [vmChainGap]. This matches the behavior of
     // `Chain.parse().toTrace()`.
     var lines = trace.trim().replaceAll(vmChainGap, '').split("\n");
     var frames = lines.take(lines.length - 1)
         .map((line) => new Frame.parseVM(line))
         .toList();

     // TODO(nweiz): Remove this when issue 23614 is fixed.
     if (!lines.last.endsWith(".da")) {
       frames.add(new Frame.parseVM(lines.last));
     }

     return frames;
   }

   /// Parses a string representation of a Chrome/V8 stack trace.
   Trace.parseV8(String trace)
       : this(trace.split("\n").skip(1)
           // It's possible that an Exception's description contains a line that
           // looks like a V8 trace line, which will screw this up.
           // Unfortunately, that's impossible to detect.
           .skipWhile((line) => !line.startsWith(_v8TraceLine))
           .map((line) => new Frame.parseV8(line)));

   /// Parses a string representation of a JavaScriptCore stack trace.
   Trace.parseJSCore(String trace)
       : this(trace.split("\n")
             .where((line) => line != "\tat ")
             .map((line) => new Frame.parseV8(line)));

   /// Parses a string representation of an Internet Explorer stack trace.
   ///
   /// IE10+ traces look just like V8 traces. Prior to IE10, stack traces can't
   /// be retrieved.
   Trace.parseIE(String trace)
       : this.parseV8(trace);

   /// Parses a string representation of a Firefox stack trace.
   Trace.parseFirefox(String trace)
       : this(trace.trim().split("\n")
           .where((line) => line.isNotEmpty && line != '[native code]')
           .map((line) => new Frame.parseFirefox(line)));

   /// Parses a string representation of a Safari stack trace.
   Trace.parseSafari(String trace)
       : this.parseFirefox(trace);

   /// Parses a string representation of a Safari 6.1+ stack trace.
   @Deprecated("Use Trace.parseSafari instead.")
   Trace.parseSafari6_1(String trace)
       : this.parseSafari(trace);

   /// Parses a string representation of a Safari 6.0 stack trace.
   @Deprecated("Use Trace.parseSafari instead.")
   Trace.parseSafari6_0(String trace)
       : this(trace.trim().split("\n")
           .where((line) => line != '[native code]')
           .map((line) => new Frame.parseFirefox(line)));

   /// Parses this package's string representation of a stack trace.
   ///
   /// This also parses string representations of [Chain]s. They parse to the
   /// same trace that [Chain.toTrace] would return.
   Trace.parseFriendly(String trace)
       : this(trace.isEmpty
             ? []
             : trace.trim().split("\n")
                 // Filter out asynchronous gaps from [Chain]s.
                 .where((line) => !line.startsWith('====='))
                 .map((line) => new Frame.parseFriendly(line)));

   /// Returns a new [Trace] comprised of [frames].
   Trace(Iterable<Frame> frames)
       : frames = new List<Frame>.unmodifiable(frames);

   /// Returns a VM-style [StackTrace] object.
   ///
   /// The return value's [toString] method will always return a string
   /// representation in the Dart VM's stack trace format, regardless of what
   /// platform is being used.
   StackTrace get vmTrace => new VMTrace(frames);

   /// Returns a terser version of [this].
   ///
   /// This is accomplished by folding together multiple stack frames from the
   /// core library or from this package, as in [foldFrames]. Remaining core
   /// library frames have their libraries, "-patch" suffixes, and line numbers
   /// removed. If the outermost frame of the stack trace is a core library
   /// frame, it's removed entirely.
   ///
   /// This won't do anything with a raw JavaScript trace, since there's no way
   /// to determine which frames come from which Dart libraries. However, the
   /// [`source_map_stack_trace`][source_map_stack_trace] package can be used to
   /// convert JavaScript traces into Dart-style traces.
   ///
   /// [source_map_stack_trace]: https://pub.dartlang.org/packages/source_map_stack_trace
   ///
   /// For custom folding, see [foldFrames].
   Trace get terse => foldFrames((_) => false, terse: true);

   /// Returns a new [Trace] based on [this] where multiple stack frames matching
   /// [predicate] are folded together.
   ///
   /// This means that whenever there are multiple frames in a row that match
   /// [predicate], only the last one is kept. This is useful for limiting the
   /// amount of library code that appears in a stack trace by only showing user
   /// code and code that's called by user code.
   ///
   /// If [terse] is true, this will also fold together frames from the core
   /// library or from this package, simplify core library frames, and
   /// potentially remove the outermost frame as in [Trace.terse].
   Trace foldFrames(bool predicate(Frame frame), {bool terse: false}) {
     if (terse) {
       var oldPredicate = predicate;
       predicate = (frame) {
         if (oldPredicate(frame)) return true;

         if (frame.isCore) return true;
         if (frame.package == 'stack_trace') return true;

         // Ignore async stack frames without any line or column information.
         // These come from the VM's async/await implementation and represent
         // internal frames. They only ever show up in stack chains and are
         // always surrounded by other traces that are actually useful, so we can
         // just get rid of them.
         // TODO(nweiz): Get rid of this logic some time after issue 22009 is
         // fixed.
         if (!frame.member.contains('<async>')) return false;
         return frame.line == null;
       };
     }

     var newFrames = <Frame>[];
     for (var frame in frames.reversed) {
       if (frame is UnparsedFrame || !predicate(frame)) {
         newFrames.add(frame);
       } else if (newFrames.isEmpty || !predicate(newFrames.last)) {
         newFrames.add(new Frame(
             frame.uri, frame.line, frame.column, frame.member));
       }
     }

     if (terse) {
       newFrames = newFrames.map((frame) {
         if (frame is UnparsedFrame || !predicate(frame)) return frame;
         var library = frame.library.replaceAll(_terseRegExp, '');
         return new Frame(Uri.parse(library), null, null, frame.member);
       }).toList();
       if (newFrames.length > 1 && newFrames.first.isCore) newFrames.removeAt(0);
     }

     return new Trace(newFrames.reversed);
   }

   /// Returns a human-readable string representation of [this].
   String toString() {
     // Figure out the longest path so we know how much to pad.
     var longest = frames.map((frame) => frame.location.length)
         .fold(0, math.max);

     // Print out the stack trace nicely formatted.
     return frames.map((frame) {
       if (frame is UnparsedFrame) return "$frame\n";
       return '${frame.location.padRight(longest)}  ${frame.member}\n';
     }).join();
   }
 }
	// Copyright (c) 2013, 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:math' as math;

	import 'chain.dart';
	import 'frame.dart';
	import 'lazy_trace.dart';
	import 'unparsed_frame.dart';
	import 'utils.dart';
	import 'vm_trace.dart';

	final _terseRegExp = new RegExp(r"(-patch)?([/\\].*)?$");

	/// A RegExp to match V8's stack traces.
	///
	/// V8's traces start with a line that's either just "Error" or else is a
	/// description of the exception that occurred. That description can be multiple
	/// lines, so we just look for any line other than the first that begins with
	/// three or four spaces and "at".
	final _v8Trace = new RegExp(r"\n ?at ");

	/// A RegExp to match indidual lines of V8's stack traces.
	///
	/// This is intended to filter out the leading exception details of the trace
	/// though it is possible for the message to match this as well.
	final _v8TraceLine = new RegExp(r" ?at ");

	/// A RegExp to match Firefox and Safari's stack traces.
	///
	/// Firefox and Safari have very similar stack trace formats, so we use the same
	/// logic for parsing them.
	///
	/// Firefox's trace frames start with the name of the function in which the
	/// error occurred, possibly including its parameters inside `()`. For example,
	/// `.VW.call$0("arg")@http://pub.dartlang.org/stuff.dart.js:560`.
	///
	/// Safari traces occasionally don't include the initial method name followed by
	/// "@", and they always have both the line and column number (or just a
	/// trailing colon if no column number is available). They can also contain
	/// empty lines or lines consisting only of `[native code]`.
	final _firefoxSafariTrace = new RegExp(
	r"^"
	r"(" // Member description. Not present in some Safari frames.
	r"([.0-9A-Za-z_$/<]\|\(.\))" // Member name and arguments.
	r"@"
	r")?"
	r"[^\s]*" // Frame URL.
	r":\d*" // Line or column number. Some older frames only have a line number.
	r"$", multiLine: true);

	/// A RegExp to match this package's stack traces.
	final _friendlyTrace = new RegExp(r"^[^\s<][^\s]*( \d+(:\d+)?)?[ \t]+[^\s]+$",
	multiLine: true);

	/// A stack trace, comprised of a list of stack frames.
	class Trace implements StackTrace {
	/// The stack frames that comprise this stack trace.
	final List<Frame> frames;

	/// Returns a human-readable representation of [stackTrace]. If [terse] is
	/// set, this folds together multiple stack frames from the Dart core
	/// libraries, so that only the core library method directly called from user
	/// code is visible (see [Trace.terse]).
	static String format(StackTrace stackTrace, {bool terse: true}) {
	var trace = new Trace.from(stackTrace);
	if (terse) trace = trace.terse;
	return trace.toString();
	}

	/// Returns the current stack trace.
	///
	/// By default, the first frame of this trace will be the line where
	/// [Trace.current] is called. If [level] is passed, the trace will start that
	/// many frames up instead.
	factory Trace.current([int level=0]) {
	if (level < 0) {
	throw new ArgumentError("Argument [level] must be greater than or equal "
	"to 0.");
	}

	var trace = new Trace.from(StackTrace.current);
	return new LazyTrace(() {
	// JS includes a frame for the call to StackTrace.current, but the VM
	// doesn't, so we skip an extra frame in a JS context.
	return new Trace(trace.frames.skip(level + (inJS ? 2 : 1)));
	});
	}

	/// Returns a new stack trace containing the same data as [trace].
	///
	/// If [trace] is a native [StackTrace], its data will be parsed out; if it's
	/// a [Trace], it will be returned as-is.
	factory Trace.from(StackTrace trace) {
	// Normally explicitly validating null arguments is bad Dart style, but here
	// the natural failure will only occur when the LazyTrace is materialized,
	// and we want to provide an error that's more local to the actual problem.
	if (trace == null) {
	throw new ArgumentError("Cannot create a Trace from null.");
	}

	if (trace is Trace) return trace;
	if (trace is Chain) return trace.toTrace();
	return new LazyTrace(() => new Trace.parse(trace.toString()));
	}

	/// Parses a string representation of a stack trace.
	///
	/// [trace] should be formatted in the same way as a Dart VM or browser stack
	/// trace. If it's formatted as a stack chain, this will return the equivalent
	/// of [Chain.toTrace].
	factory Trace.parse(String trace) {
	try {
	if (trace.isEmpty) return new Trace(<Frame>[]);
	if (trace.contains(_v8Trace)) return new Trace.parseV8(trace);
	if (trace.contains("\tat ")) return new Trace.parseJSCore(trace);
	if (trace.contains(_firefoxSafariTrace)) {
	return new Trace.parseFirefox(trace);
	}
	if (trace.contains(chainGap)) return new Chain.parse(trace).toTrace();
	if (trace.contains(_friendlyTrace)) {
	return new Trace.parseFriendly(trace);
	}

	// Default to parsing the stack trace as a VM trace. This is also hit on
	// IE and Safari, where the stack trace is just an empty string (issue
	// 11257).
	return new Trace.parseVM(trace);
	} on FormatException catch (error) {
	throw new FormatException('${error.message}\nStack trace:\n$trace');
	}
	}

	/// Parses a string representation of a Dart VM stack trace.
	Trace.parseVM(String trace)
	: this(_parseVM(trace));

	static List<Frame> _parseVM(String trace) {
	// Ignore [vmChainGap]. This matches the behavior of
	// `Chain.parse().toTrace()`.
	var lines = trace.trim().replaceAll(vmChainGap, '').split("\n");
	var frames = lines.take(lines.length - 1)
	.map((line) => new Frame.parseVM(line))
	.toList();

	// TODO(nweiz): Remove this when issue 23614 is fixed.
	if (!lines.last.endsWith(".da")) {
	frames.add(new Frame.parseVM(lines.last));
	}

	return frames;
	}

	/// Parses a string representation of a Chrome/V8 stack trace.
	Trace.parseV8(String trace)
	: this(trace.split("\n").skip(1)
	// It's possible that an Exception's description contains a line that
	// looks like a V8 trace line, which will screw this up.
	// Unfortunately, that's impossible to detect.
	.skipWhile((line) => !line.startsWith(_v8TraceLine))
	.map((line) => new Frame.parseV8(line)));

	/// Parses a string representation of a JavaScriptCore stack trace.
	Trace.parseJSCore(String trace)
	: this(trace.split("\n")
	.where((line) => line != "\tat ")
	.map((line) => new Frame.parseV8(line)));

	/// Parses a string representation of an Internet Explorer stack trace.
	///
	/// IE10+ traces look just like V8 traces. Prior to IE10, stack traces can't
	/// be retrieved.
	Trace.parseIE(String trace)
	: this.parseV8(trace);

	/// Parses a string representation of a Firefox stack trace.
	Trace.parseFirefox(String trace)
	: this(trace.trim().split("\n")
	.where((line) => line.isNotEmpty && line != '[native code]')
	.map((line) => new Frame.parseFirefox(line)));

	/// Parses a string representation of a Safari stack trace.
	Trace.parseSafari(String trace)
	: this.parseFirefox(trace);

	/// Parses a string representation of a Safari 6.1+ stack trace.
	@Deprecated("Use Trace.parseSafari instead.")
	Trace.parseSafari6_1(String trace)
	: this.parseSafari(trace);

	/// Parses a string representation of a Safari 6.0 stack trace.
	@Deprecated("Use Trace.parseSafari instead.")
	Trace.parseSafari6_0(String trace)
	: this(trace.trim().split("\n")
	.where((line) => line != '[native code]')
	.map((line) => new Frame.parseFirefox(line)));

	/// Parses this package's string representation of a stack trace.
	///
	/// This also parses string representations of [Chain]s. They parse to the
	/// same trace that [Chain.toTrace] would return.
	Trace.parseFriendly(String trace)
	: this(trace.isEmpty
	? []
	: trace.trim().split("\n")
	// Filter out asynchronous gaps from [Chain]s.
	.where((line) => !line.startsWith('====='))
	.map((line) => new Frame.parseFriendly(line)));

	/// Returns a new [Trace] comprised of [frames].
	Trace(Iterable<Frame> frames)
	: frames = new List<Frame>.unmodifiable(frames);

	/// Returns a VM-style [StackTrace] object.
	///
	/// The return value's [toString] method will always return a string
	/// representation in the Dart VM's stack trace format, regardless of what
	/// platform is being used.
	StackTrace get vmTrace => new VMTrace(frames);

	/// Returns a terser version of [this].
	///
	/// This is accomplished by folding together multiple stack frames from the
	/// core library or from this package, as in [foldFrames]. Remaining core
	/// library frames have their libraries, "-patch" suffixes, and line numbers
	/// removed. If the outermost frame of the stack trace is a core library
	/// frame, it's removed entirely.
	///
	/// This won't do anything with a raw JavaScript trace, since there's no way
	/// to determine which frames come from which Dart libraries. However, the
	/// [`source_map_stack_trace`][source_map_stack_trace] package can be used to
	/// convert JavaScript traces into Dart-style traces.
	///
	/// [source_map_stack_trace]: https://pub.dartlang.org/packages/source_map_stack_trace
	///
	/// For custom folding, see [foldFrames].
	Trace get terse => foldFrames((_) => false, terse: true);

	/// Returns a new [Trace] based on [this] where multiple stack frames matching
	/// [predicate] are folded together.
	///
	/// This means that whenever there are multiple frames in a row that match
	/// [predicate], only the last one is kept. This is useful for limiting the
	/// amount of library code that appears in a stack trace by only showing user
	/// code and code that's called by user code.
	///
	/// If [terse] is true, this will also fold together frames from the core
	/// library or from this package, simplify core library frames, and
	/// potentially remove the outermost frame as in [Trace.terse].
	Trace foldFrames(bool predicate(Frame frame), {bool terse: false}) {
	if (terse) {
	var oldPredicate = predicate;
	predicate = (frame) {
	if (oldPredicate(frame)) return true;

	if (frame.isCore) return true;
	if (frame.package == 'stack_trace') return true;

	// Ignore async stack frames without any line or column information.
	// These come from the VM's async/await implementation and represent
	// internal frames. They only ever show up in stack chains and are
	// always surrounded by other traces that are actually useful, so we can
	// just get rid of them.
	// TODO(nweiz): Get rid of this logic some time after issue 22009 is
	// fixed.
	if (!frame.member.contains('<async>')) return false;
	return frame.line == null;
	};
	}

	var newFrames = <Frame>[];
	for (var frame in frames.reversed) {
	if (frame is UnparsedFrame \|\| !predicate(frame)) {
	newFrames.add(frame);
	} else if (newFrames.isEmpty \|\| !predicate(newFrames.last)) {
	newFrames.add(new Frame(
	frame.uri, frame.line, frame.column, frame.member));
	}
	}

	if (terse) {
	newFrames = newFrames.map((frame) {
	if (frame is UnparsedFrame \|\| !predicate(frame)) return frame;
	var library = frame.library.replaceAll(_terseRegExp, '');
	return new Frame(Uri.parse(library), null, null, frame.member);
	}).toList();
	if (newFrames.length > 1 && newFrames.first.isCore) newFrames.removeAt(0);
	}

	return new Trace(newFrames.reversed);
	}

	/// Returns a human-readable string representation of [this].
	String toString() {
	// Figure out the longest path so we know how much to pad.
	var longest = frames.map((frame) => frame.location.length)
	.fold(0, math.max);

	// Print out the stack trace nicely formatted.
	return frames.map((frame) {
	if (frame is UnparsedFrame) return "$frame\n";
	return '${frame.location.padRight(longest)} ${frame.member}\n';
	}).join();
	}
	}