tools/coverage.dart - sdk.git - 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.

 // This test forks a second vm process that runs a dart script as
 // a debug target, single stepping through the entire program, and
 // recording each breakpoint. At the end, a coverage map of the source
 // is printed.
 //
 // Usage: dart coverage.dart [--wire] [--verbose] target_script.dart
 //
 //   --wire      see json messages sent between the processes.
 //   --verbose   see the stdout and stderr output of the debug
 //               target process.

 import "dart:convert";
 import "dart:io";


 // Whether or not to print debug target process on the console.
 var showDebuggeeOutput = false;

 // Whether or not to print the debugger wire messages on the console.
 var verboseWire = false;

 var debugger = null;

 class Program {
   static int numBps = 0;

   // Maps source code url to source.
   static var sources = new Map<String, Source>();

   // Takes a JSON Debugger response and increments the count for
   // the source position.
   static void recordBp(Map<String,dynamic> msg) {
     // Progress indicator.
     if (++numBps % 1000 == 0) print(numBps);
     var location = msg["params"]["location"];
     if (location == null) return;
     String url = location["url"];
     assert(url != null);
     int libId = location["libraryId"];
     assert(libId != null);
     int tokenPos = location["tokenOffset"];;
     Source s = sources[url];
     if (s == null) {
       debugger.getLineNumberTable(url, libId);
       s = new Source(url);
       sources[url] = s;
     }
     s.recordBp(tokenPos);
   }

   // Prints the annotated source code.
   static void printCoverage() {
     print("Coverage info collected from $numBps breakpoints:");
     for(Source s in sources.values) s.printCoverage();
   }
 }


 class Source {
   final String url;

   // Maps token position to breakpoint count.
   final tokenCounts = new Map<int,int>();

   // Maps token position to line number.
   final tokenPosToLine = new Map<int,int>();

   Source(this.url);

   void recordBp(int tokenPos) {
     var count = tokenCounts[tokenPos];
     tokenCounts[tokenPos] = count == null ? 1 : count + 1;
   }

   void SetLineInfo(List lineInfoTable) {
     // Each line is encoded as an array with first element being the line
     // number, followed by pairs of (tokenPosition, columnNumber).
     lineInfoTable.forEach((List<int> line) {
       int lineNumber = line[0];
       for (int t = 1; t < line.length; t += 2) {
         assert(tokenPosToLine[line[t]] == null);
         tokenPosToLine[line[t]] = lineNumber;
       }
     });
   }

   // Print out the annotated source code. For each line that has seen
   // a breakpoint, print out the maximum breakpoint count for all
   // tokens in the line.
   void printCoverage() {
     var lineCounts = new Map<int,int>();  // BP counts for each line.
     print(url);
     tokenCounts.forEach((tp, bpCount) {
       int lineNumber = tokenPosToLine[tp];
       var lineCount = lineCounts[lineNumber];
       // Remember maximum breakpoint count of all tokens in this line.
       if (lineCount == null || lineCount < bpCount) {
         lineCounts[lineNumber] = bpCount;
       }
     });

     String srcPath = Uri.parse(url).toFilePath();
     List lines = new File(srcPath).readAsLinesSync();
     for (int line = 1; line <= lines.length; line++) {
       String prefix = "      ";
       if (lineCounts.containsKey(line)) {
         prefix = lineCounts[line].toString();
         StringBuffer b = new StringBuffer();
         for (int i = prefix.length; i < 6; i++) b.write(" ");
         b.write(prefix);
         prefix = b.toString();
       }
       print("${prefix}|${lines[line-1]}");
     }
   }
 }


 class StepCmd {
   Map msg;
   StepCmd(int isolateId) {
     msg = {"id": 0, "command": "stepInto", "params": {"isolateId": isolateId}};
   }
   void handleResponse(Map response) {}
 }


 class GetLineTableCmd {
   Map msg;
   GetLineTableCmd(int isolateId, int libraryId, String url) {
     msg = { "id": 0,
             "command":  "getLineNumberTable",
             "params": { "isolateId" : isolateId,
                         "libraryId": libraryId,
                         "url": url } };
   }

   void handleResponse(Map response) {
     var url = msg["params"]["url"];
     Source s = Program.sources[url];
     assert(s != null);
     s.SetLineInfo(response["result"]["lines"]);
   }
 }


 class GetLibrariesCmd {
   Map msg;
   GetLibrariesCmd(int isolateId) {
     msg = { "id": 0,
             "command":  "getLibraries",
             "params": { "isolateId" : isolateId } };
   }

   void handleResponse(Map response) {
     List libs = response["result"]["libraries"];
     for (var lib in libs) {
       String url = lib["url"];
       int libraryId = lib["id"];
       bool enable = !url.startsWith("dart:") && !url.startsWith("package:");
       if (enable) {
         print("Enable stepping for '$url'");
         debugger.enableDebugging(libraryId, true);
       }
     }
   }
 }


 class SetLibraryPropertiesCmd {
   Map msg;
   SetLibraryPropertiesCmd(int isolateId, int libraryId, bool enableDebugging) {
     // Note that in the debugger protocol, boolean values true and false
     // must be sent as string literals.
     msg = { "id": 0,
             "command":  "setLibraryProperties",
             "params": { "isolateId" : isolateId,
                         "libraryId": libraryId,
                         "debuggingEnabled": "$enableDebugging" } };
   }

   void handleResponse(Map response) {
     // Nothing to do.
   }
 }


 class Debugger {
   // Debug target process properties.
   Process targetProcess;
   Socket socket;
   bool cleanupDone = false;
   JsonBuffer responses = new JsonBuffer();
   List<String> errors = new List();

   // Data collected from debug target.
   Map currentMessage = null;  // Currently handled message sent by target.
   var outstandingCommand = null;
   var queuedCommands = new List();
   String scriptUrl = null;
   bool shutdownEventSeen = false;
   int isolateId = 0;
   int libraryId = null;

   int nextMessageId = 0;
   bool isPaused = false;
   bool pendingAck = false;

   Debugger(this.targetProcess) {
     var stdoutStringStream = targetProcess.stdout
         .transform(UTF8.decoder)
         .transform(new LineSplitter());
     stdoutStringStream.listen((line) {
       if (showDebuggeeOutput) {
         print("TARG: $line");
       }
       if (line.startsWith("Debugger listening")) {
         RegExp portExpr = new RegExp(r"\d+");
         var port = portExpr.stringMatch(line);
         var pid = targetProcess.pid;
         print("Coverage target process (pid $pid) found "
               "listening on port $port.");
         openConnection(int.parse(port));
       }
     });

     var stderrStringStream = targetProcess.stderr
         .transform(UTF8.decoder)
         .transform(new LineSplitter());
     stderrStringStream.listen((line) {
       if (showDebuggeeOutput) {
         print("TARG: $line");
       }
     });
   }

   // Handle debugger events, updating the debugger state.
   void handleEvent(Map<String,dynamic> msg) {
     if (msg["event"] == "isolate") {
       if (msg["params"]["reason"] == "created") {
         isolateId = msg["params"]["id"];
         assert(isolateId != null);
         print("Debuggee isolate id $isolateId created.");
       } else if (msg["params"]["reason"] == "shutdown") {
         print("Debuggee isolate id ${msg["params"]["id"]} shut down.");
         shutdownEventSeen = true;
       }
     } else if (msg["event"] == "breakpointResolved") {
       var bpId = msg["params"]["breakpointId"];
       assert(bpId != null);
       var isolateId = msg["params"]["isolateId"];
       assert(isolateId != null);
       var location = msg["params"]["location"];
       assert(location != null);
       print("Isolate $isolateId: breakpoint $bpId resolved"
             " at location $location");
       // We may want to maintain a table of breakpoints in the future.
     } else if (msg["event"] == "paused") {
       isPaused = true;
       if (libraryId == null) {
         libraryId = msg["params"]["location"]["libraryId"];
         assert(libraryId != null);
         // This is the first paused event we got. Get all libraries from
         // the debugger so we can turn on debugging events for them.
         getLibraries();
       }
       if (msg["params"]["reason"] == "breakpoint") {
         Program.recordBp(msg);
       }
     } else {
       error("Error: unknown debugger event received");
     }
   }

   // Handle one JSON message object.
   void handleMessage(Map<String,dynamic> receivedMsg) {
     currentMessage = receivedMsg;
     if (receivedMsg["event"] != null) {
       handleEvent(receivedMsg);
       if (errorsDetected) {
         error("Error while handling event message");
         error("Event received from coverage target: $receivedMsg");
       }
     } else if (receivedMsg["id"] != null) {
       // This is a response to the last command we sent.
       int id = receivedMsg["id"];
       assert(outstandingCommand != null);
       assert(outstandingCommand.msg["id"] == id);
       outstandingCommand.handleResponse(receivedMsg);
       outstandingCommand = null;
     } else {
       error("Unexpected message from target");
     }
   }

   // Handle data received over the wire from the coverage target
   // process. Split input from JSON wire format into individual
   // message objects (maps).
   void handleMessages() {
     var msg = responses.getNextMessage();
     while (msg != null) {
       if (verboseWire) print("RECV: $msg");
       if (responses.haveGarbage()) {
         error("Error: leftover text after message: '${responses.buffer}'");
         error("Previous message may be malformed, was: '$msg'");
         cleanup();
         return;
       }
       var msgObj = JSON.decode(msg);
       handleMessage(msgObj);
       if (errorsDetected) {
         error("Error while handling message from coverage target");
         error("Message received from coverage target: $msg");
         cleanup();
         return;
       }
       if (shutdownEventSeen) {
         if (outstandingCommand != null) {
           error("Error: outstanding command when shutdown received");
         }
         cleanup();
         return;
       }
       if (isPaused && (outstandingCommand == null)) {
         var cmd = queuedCommands.length > 0 ? queuedCommands.removeAt(0) : null;
         if (cmd == null) {
           cmd = new StepCmd(isolateId);
           isPaused = false;
         }
         sendMessage(cmd.msg);
         outstandingCommand = cmd;
       }
       msg = responses.getNextMessage();
     }
   }

   // Send a debugger command to the target VM.
   void sendMessage(Map<String,dynamic> msg) {
     assert(msg["id"] != null);
     msg["id"] = nextMessageId++;
     String jsonMsg = JSON.encode(msg);
     if (verboseWire) print("SEND: $jsonMsg");
     socket.write(jsonMsg);
   }

   void getLineNumberTable(String url, int libId) {
     queuedCommands.add(new GetLineTableCmd(isolateId, libId, url));
   }

   void getLibraries() {
     queuedCommands.add(new GetLibrariesCmd(isolateId));
   }

   void enableDebugging(libraryId, enable) {
     queuedCommands.add(new SetLibraryPropertiesCmd(isolateId, libraryId, enable));
   }

   bool get errorsDetected => errors.length > 0;

   // Record error message.
   void error(String s) {
     errors.add(s);
   }

   void openConnection(int portNumber) {
     Socket.connect("127.0.0.1", portNumber).then((s) {
       socket = s;
       socket.setOption(SocketOption.TCP_NODELAY, true);
       var stringStream = socket.transform(UTF8.decoder);
       stringStream.listen(
           (str) {
             try {
               responses.append(str);
               handleMessages();
             } catch(e, trace) {
               print("Unexpected exception:\n$e\n$trace");
               cleanup();
             }
           },
           onDone: () {
             print("Connection closed by coverage target");
             cleanup();
           },
           onError: (e) {
             print("Error '$e' detected in input stream from coverage target");
             cleanup();
           });
       },
       onError: (e, trace) {
         String msg = "Error while connecting to coverage target: $e";
         if (trace != null) msg += "\nStackTrace: $trace";
         error(msg);
         cleanup();
      });
   }

   void cleanup() {
     if (cleanupDone) return;
     if (socket != null) {
       socket.close().catchError((error) {
         // Print this directly in addition to adding it to the
         // error message queue, in case the error message queue
         // gets printed before this error handler is called.
         print("Error occurred while closing socket: $error");
         error("Error while closing socket: $error");
       });
     }
     var targetPid = targetProcess.pid;
     print("Sending kill signal to process $targetPid.");
     targetProcess.kill();
     // If the process was already dead exitCode is already
     // available and we call exit() in the next event loop cycle.
     // Otherwise this will wait for the process to exit.

     targetProcess.exitCode.then((exitCode) {
       print("Process $targetPid terminated with exit code $exitCode.");
       if (errorsDetected) {
         print("\n===== Errors detected: =====");
         for (int i = 0; i < errors.length; i++) print(errors[i]);
         print("============================\n");
       }
       Program.printCoverage();
       exit(errors.length);
     });
     cleanupDone = true;
   }
 }


 // Class to buffer wire protocol data from coverage target and
 // break it down to individual json messages.
 class JsonBuffer {
   String buffer = null;

   append(String s) {
     if (buffer == null || buffer.length == 0) {
       buffer = s;
     } else {
       buffer = buffer + s;
     }
   }

   String getNextMessage() {
     if (buffer == null) return null;
     int msgLen = objectLength();
     if (msgLen == 0) return null;
     String msg = null;
     if (msgLen == buffer.length) {
       msg = buffer;
       buffer = null;
     } else {
       assert(msgLen < buffer.length);
       msg = buffer.substring(0, msgLen);
       buffer = buffer.substring(msgLen);
     }
     return msg;
   }

   bool haveGarbage() {
     if (buffer == null || buffer.length == 0) return false;
     var i = 0, char = " ";
     while (i < buffer.length) {
       char = buffer[i];
       if (char != " " && char != "\n" && char != "\r" && char != "\t") break;
       i++;
     }
     if (i >= buffer.length) {
       return false;
     } else {
       return char != "{";
     }
   }

   // Returns the character length of the next json message in the
   // buffer, or 0 if there is only a partial message in the buffer.
   // The object value must start with '{' and continues to the
   // matching '}'. No attempt is made to otherwise validate the contents
   // as JSON. If it is invalid, a later JSON.decode() will fail.
   int objectLength() {
     int skipWhitespace(int index) {
       while (index < buffer.length) {
         String char = buffer[index];
         if (char != " " && char != "\n" && char != "\r" && char != "\t") break;
         index++;
       }
       return index;
     }
     int skipString(int index) {
       assert(buffer[index - 1] == '"');
       while (index < buffer.length) {
         String char = buffer[index];
         if (char == '"') return index + 1;
         if (char == r'\') index++;
         if (index == buffer.length) return index;
         index++;
       }
       return index;
     }
     int index = 0;
     index = skipWhitespace(index);
     // Bail out if the first non-whitespace character isn't '{'.
     if (index == buffer.length || buffer[index] != '{') return 0;
     int nesting = 0;
     while (index < buffer.length) {
       String char = buffer[index++];
       if (char == '{') {
         nesting++;
       } else if (char == '}') {
         nesting--;
         if (nesting == 0) return index;
       } else if (char == '"') {
         // Strings can contain braces. Skip their content.
         index = skipString(index);
       }
     }
     return 0;
   }
 }


 void main(List<String> arguments) {
   var targetOpts = [ "--debug:0" ];
   for (String str in arguments) {
     switch (str) {
       case "--verbose":
         showDebuggeeOutput = true;
         break;
       case "--wire":
         verboseWire = true;
         break;
       default:
         targetOpts.add(str);
         break;
     }
   }

   Process.start(Platform.executable, targetOpts).then((Process process) {
     process.stdin.close();
     debugger = new Debugger(process);
   });
 }
	// 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.

	// This test forks a second vm process that runs a dart script as
	// a debug target, single stepping through the entire program, and
	// recording each breakpoint. At the end, a coverage map of the source
	// is printed.
	//
	// Usage: dart coverage.dart [--wire] [--verbose] target_script.dart
	//
	// --wire see json messages sent between the processes.
	// --verbose see the stdout and stderr output of the debug
	// target process.

	import "dart:convert";
	import "dart:io";


	// Whether or not to print debug target process on the console.
	var showDebuggeeOutput = false;

	// Whether or not to print the debugger wire messages on the console.
	var verboseWire = false;

	var debugger = null;

	class Program {
	static int numBps = 0;

	// Maps source code url to source.
	static var sources = new Map<String, Source>();

	// Takes a JSON Debugger response and increments the count for
	// the source position.
	static void recordBp(Map<String,dynamic> msg) {
	// Progress indicator.
	if (++numBps % 1000 == 0) print(numBps);
	var location = msg["params"]["location"];
	if (location == null) return;
	String url = location["url"];
	assert(url != null);
	int libId = location["libraryId"];
	assert(libId != null);
	int tokenPos = location["tokenOffset"];;
	Source s = sources[url];
	if (s == null) {
	debugger.getLineNumberTable(url, libId);
	s = new Source(url);
	sources[url] = s;
	}
	s.recordBp(tokenPos);
	}

	// Prints the annotated source code.
	static void printCoverage() {
	print("Coverage info collected from $numBps breakpoints:");
	for(Source s in sources.values) s.printCoverage();
	}
	}


	class Source {
	final String url;

	// Maps token position to breakpoint count.
	final tokenCounts = new Map<int,int>();

	// Maps token position to line number.
	final tokenPosToLine = new Map<int,int>();

	Source(this.url);

	void recordBp(int tokenPos) {
	var count = tokenCounts[tokenPos];
	tokenCounts[tokenPos] = count == null ? 1 : count + 1;
	}

	void SetLineInfo(List lineInfoTable) {
	// Each line is encoded as an array with first element being the line
	// number, followed by pairs of (tokenPosition, columnNumber).
	lineInfoTable.forEach((List<int> line) {
	int lineNumber = line[0];
	for (int t = 1; t < line.length; t += 2) {
	assert(tokenPosToLine[line[t]] == null);
	tokenPosToLine[line[t]] = lineNumber;
	}
	});
	}

	// Print out the annotated source code. For each line that has seen
	// a breakpoint, print out the maximum breakpoint count for all
	// tokens in the line.
	void printCoverage() {
	var lineCounts = new Map<int,int>(); // BP counts for each line.
	print(url);
	tokenCounts.forEach((tp, bpCount) {
	int lineNumber = tokenPosToLine[tp];
	var lineCount = lineCounts[lineNumber];
	// Remember maximum breakpoint count of all tokens in this line.
	if (lineCount == null \|\| lineCount < bpCount) {
	lineCounts[lineNumber] = bpCount;
	}
	});

	String srcPath = Uri.parse(url).toFilePath();
	List lines = new File(srcPath).readAsLinesSync();
	for (int line = 1; line <= lines.length; line++) {
	String prefix = " ";
	if (lineCounts.containsKey(line)) {
	prefix = lineCounts[line].toString();
	StringBuffer b = new StringBuffer();
	for (int i = prefix.length; i < 6; i++) b.write(" ");
	b.write(prefix);
	prefix = b.toString();
	}
	print("${prefix}\|${lines[line-1]}");
	}
	}
	}


	class StepCmd {
	Map msg;
	StepCmd(int isolateId) {
	msg = {"id": 0, "command": "stepInto", "params": {"isolateId": isolateId}};
	}
	void handleResponse(Map response) {}
	}


	class GetLineTableCmd {
	Map msg;
	GetLineTableCmd(int isolateId, int libraryId, String url) {
	msg = { "id": 0,
	"command": "getLineNumberTable",
	"params": { "isolateId" : isolateId,
	"libraryId": libraryId,
	"url": url } };
	}

	void handleResponse(Map response) {
	var url = msg["params"]["url"];
	Source s = Program.sources[url];
	assert(s != null);
	s.SetLineInfo(response["result"]["lines"]);
	}
	}


	class GetLibrariesCmd {
	Map msg;
	GetLibrariesCmd(int isolateId) {
	msg = { "id": 0,
	"command": "getLibraries",
	"params": { "isolateId" : isolateId } };
	}

	void handleResponse(Map response) {
	List libs = response["result"]["libraries"];
	for (var lib in libs) {
	String url = lib["url"];
	int libraryId = lib["id"];
	bool enable = !url.startsWith("dart:") && !url.startsWith("package:");
	if (enable) {
	print("Enable stepping for '$url'");
	debugger.enableDebugging(libraryId, true);
	}
	}
	}
	}


	class SetLibraryPropertiesCmd {
	Map msg;
	SetLibraryPropertiesCmd(int isolateId, int libraryId, bool enableDebugging) {
	// Note that in the debugger protocol, boolean values true and false
	// must be sent as string literals.
	msg = { "id": 0,
	"command": "setLibraryProperties",
	"params": { "isolateId" : isolateId,
	"libraryId": libraryId,
	"debuggingEnabled": "$enableDebugging" } };
	}

	void handleResponse(Map response) {
	// Nothing to do.
	}
	}


	class Debugger {
	// Debug target process properties.
	Process targetProcess;
	Socket socket;
	bool cleanupDone = false;
	JsonBuffer responses = new JsonBuffer();
	List<String> errors = new List();

	// Data collected from debug target.
	Map currentMessage = null; // Currently handled message sent by target.
	var outstandingCommand = null;
	var queuedCommands = new List();
	String scriptUrl = null;
	bool shutdownEventSeen = false;
	int isolateId = 0;
	int libraryId = null;

	int nextMessageId = 0;
	bool isPaused = false;
	bool pendingAck = false;

	Debugger(this.targetProcess) {
	var stdoutStringStream = targetProcess.stdout
	.transform(UTF8.decoder)
	.transform(new LineSplitter());
	stdoutStringStream.listen((line) {
	if (showDebuggeeOutput) {
	print("TARG: $line");
	}
	if (line.startsWith("Debugger listening")) {
	RegExp portExpr = new RegExp(r"\d+");
	var port = portExpr.stringMatch(line);
	var pid = targetProcess.pid;
	print("Coverage target process (pid $pid) found "
	"listening on port $port.");
	openConnection(int.parse(port));
	}
	});

	var stderrStringStream = targetProcess.stderr
	.transform(UTF8.decoder)
	.transform(new LineSplitter());
	stderrStringStream.listen((line) {
	if (showDebuggeeOutput) {
	print("TARG: $line");
	}
	});
	}

	// Handle debugger events, updating the debugger state.
	void handleEvent(Map<String,dynamic> msg) {
	if (msg["event"] == "isolate") {
	if (msg["params"]["reason"] == "created") {
	isolateId = msg["params"]["id"];
	assert(isolateId != null);
	print("Debuggee isolate id $isolateId created.");
	} else if (msg["params"]["reason"] == "shutdown") {
	print("Debuggee isolate id ${msg["params"]["id"]} shut down.");
	shutdownEventSeen = true;
	}
	} else if (msg["event"] == "breakpointResolved") {
	var bpId = msg["params"]["breakpointId"];
	assert(bpId != null);
	var isolateId = msg["params"]["isolateId"];
	assert(isolateId != null);
	var location = msg["params"]["location"];
	assert(location != null);
	print("Isolate $isolateId: breakpoint $bpId resolved"
	" at location $location");
	// We may want to maintain a table of breakpoints in the future.
	} else if (msg["event"] == "paused") {
	isPaused = true;
	if (libraryId == null) {
	libraryId = msg["params"]["location"]["libraryId"];
	assert(libraryId != null);
	// This is the first paused event we got. Get all libraries from
	// the debugger so we can turn on debugging events for them.
	getLibraries();
	}
	if (msg["params"]["reason"] == "breakpoint") {
	Program.recordBp(msg);
	}
	} else {
	error("Error: unknown debugger event received");
	}
	}

	// Handle one JSON message object.
	void handleMessage(Map<String,dynamic> receivedMsg) {
	currentMessage = receivedMsg;
	if (receivedMsg["event"] != null) {
	handleEvent(receivedMsg);
	if (errorsDetected) {
	error("Error while handling event message");
	error("Event received from coverage target: $receivedMsg");
	}
	} else if (receivedMsg["id"] != null) {
	// This is a response to the last command we sent.
	int id = receivedMsg["id"];
	assert(outstandingCommand != null);
	assert(outstandingCommand.msg["id"] == id);
	outstandingCommand.handleResponse(receivedMsg);
	outstandingCommand = null;
	} else {
	error("Unexpected message from target");
	}
	}

	// Handle data received over the wire from the coverage target
	// process. Split input from JSON wire format into individual
	// message objects (maps).
	void handleMessages() {
	var msg = responses.getNextMessage();
	while (msg != null) {
	if (verboseWire) print("RECV: $msg");
	if (responses.haveGarbage()) {
	error("Error: leftover text after message: '${responses.buffer}'");
	error("Previous message may be malformed, was: '$msg'");
	cleanup();
	return;
	}
	var msgObj = JSON.decode(msg);
	handleMessage(msgObj);
	if (errorsDetected) {
	error("Error while handling message from coverage target");
	error("Message received from coverage target: $msg");
	cleanup();
	return;
	}
	if (shutdownEventSeen) {
	if (outstandingCommand != null) {
	error("Error: outstanding command when shutdown received");
	}
	cleanup();
	return;
	}
	if (isPaused && (outstandingCommand == null)) {
	var cmd = queuedCommands.length > 0 ? queuedCommands.removeAt(0) : null;
	if (cmd == null) {
	cmd = new StepCmd(isolateId);
	isPaused = false;
	}
	sendMessage(cmd.msg);
	outstandingCommand = cmd;
	}
	msg = responses.getNextMessage();
	}
	}

	// Send a debugger command to the target VM.
	void sendMessage(Map<String,dynamic> msg) {
	assert(msg["id"] != null);
	msg["id"] = nextMessageId++;
	String jsonMsg = JSON.encode(msg);
	if (verboseWire) print("SEND: $jsonMsg");
	socket.write(jsonMsg);
	}

	void getLineNumberTable(String url, int libId) {
	queuedCommands.add(new GetLineTableCmd(isolateId, libId, url));
	}

	void getLibraries() {
	queuedCommands.add(new GetLibrariesCmd(isolateId));
	}

	void enableDebugging(libraryId, enable) {
	queuedCommands.add(new SetLibraryPropertiesCmd(isolateId, libraryId, enable));
	}

	bool get errorsDetected => errors.length > 0;

	// Record error message.
	void error(String s) {
	errors.add(s);
	}

	void openConnection(int portNumber) {
	Socket.connect("127.0.0.1", portNumber).then((s) {
	socket = s;
	socket.setOption(SocketOption.TCP_NODELAY, true);
	var stringStream = socket.transform(UTF8.decoder);
	stringStream.listen(
	(str) {
	try {
	responses.append(str);
	handleMessages();
	} catch(e, trace) {
	print("Unexpected exception:\n$e\n$trace");
	cleanup();
	}
	},
	onDone: () {
	print("Connection closed by coverage target");
	cleanup();
	},
	onError: (e) {
	print("Error '$e' detected in input stream from coverage target");
	cleanup();
	});
	},
	onError: (e, trace) {
	String msg = "Error while connecting to coverage target: $e";
	if (trace != null) msg += "\nStackTrace: $trace";
	error(msg);
	cleanup();
	});
	}

	void cleanup() {
	if (cleanupDone) return;
	if (socket != null) {
	socket.close().catchError((error) {
	// Print this directly in addition to adding it to the
	// error message queue, in case the error message queue
	// gets printed before this error handler is called.
	print("Error occurred while closing socket: $error");
	error("Error while closing socket: $error");
	});
	}
	var targetPid = targetProcess.pid;
	print("Sending kill signal to process $targetPid.");
	targetProcess.kill();
	// If the process was already dead exitCode is already
	// available and we call exit() in the next event loop cycle.
	// Otherwise this will wait for the process to exit.

	targetProcess.exitCode.then((exitCode) {
	print("Process $targetPid terminated with exit code $exitCode.");
	if (errorsDetected) {
	print("\n===== Errors detected: =====");
	for (int i = 0; i < errors.length; i++) print(errors[i]);
	print("============================\n");
	}
	Program.printCoverage();
	exit(errors.length);
	});
	cleanupDone = true;
	}
	}


	// Class to buffer wire protocol data from coverage target and
	// break it down to individual json messages.
	class JsonBuffer {
	String buffer = null;

	append(String s) {
	if (buffer == null \|\| buffer.length == 0) {
	buffer = s;
	} else {
	buffer = buffer + s;
	}
	}

	String getNextMessage() {
	if (buffer == null) return null;
	int msgLen = objectLength();
	if (msgLen == 0) return null;
	String msg = null;
	if (msgLen == buffer.length) {
	msg = buffer;
	buffer = null;
	} else {
	assert(msgLen < buffer.length);
	msg = buffer.substring(0, msgLen);
	buffer = buffer.substring(msgLen);
	}
	return msg;
	}

	bool haveGarbage() {
	if (buffer == null \|\| buffer.length == 0) return false;
	var i = 0, char = " ";
	while (i < buffer.length) {
	char = buffer[i];
	if (char != " " && char != "\n" && char != "\r" && char != "\t") break;
	i++;
	}
	if (i >= buffer.length) {
	return false;
	} else {
	return char != "{";
	}
	}

	// Returns the character length of the next json message in the
	// buffer, or 0 if there is only a partial message in the buffer.
	// The object value must start with '{' and continues to the
	// matching '}'. No attempt is made to otherwise validate the contents
	// as JSON. If it is invalid, a later JSON.decode() will fail.
	int objectLength() {
	int skipWhitespace(int index) {
	while (index < buffer.length) {
	String char = buffer[index];
	if (char != " " && char != "\n" && char != "\r" && char != "\t") break;
	index++;
	}
	return index;
	}
	int skipString(int index) {
	assert(buffer[index - 1] == '"');
	while (index < buffer.length) {
	String char = buffer[index];
	if (char == '"') return index + 1;
	if (char == r'\') index++;
	if (index == buffer.length) return index;
	index++;
	}
	return index;
	}
	int index = 0;
	index = skipWhitespace(index);
	// Bail out if the first non-whitespace character isn't '{'.
	if (index == buffer.length \|\| buffer[index] != '{') return 0;
	int nesting = 0;
	while (index < buffer.length) {
	String char = buffer[index++];
	if (char == '{') {
	nesting++;
	} else if (char == '}') {
	nesting--;
	if (nesting == 0) return index;
	} else if (char == '"') {
	// Strings can contain braces. Skip their content.
	index = skipString(index);
	}
	}
	return 0;
	}
	}


	void main(List<String> arguments) {
	var targetOpts = [ "--debug:0" ];
	for (String str in arguments) {
	switch (str) {
	case "--verbose":
	showDebuggeeOutput = true;
	break;
	case "--wire":
	verboseWire = true;
	break;
	default:
	targetOpts.add(str);
	break;
	}
	}

	Process.start(Platform.executable, targetOpts).then((Process process) {
	process.stdin.close();
	debugger = new Debugger(process);
	});
	}