feat(filters): Add a stacktrace filter.

Still pretty basic, and needs tests. Addresses #1.

Makefile

@@ -1,6 +1,6 @@
 ci: test
 
-test: lint
+test: node_modules lint
 	npm $@
 
 lint:

example/stacktrace/.eslintrc.json

@@ -0,0 +1,3 @@
+{
+  "extends": "semistandard"
+}

example/stacktrace/LICENSE

@@ -0,0 +1,13 @@
+
+Copyright 2016 Red Hat, Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.

example/stacktrace/index.js

@@ -0,0 +1,24 @@
+require('clarify');
+
+const LightBright = require('../../');
+LightBright.addFilter(LightBright.builtins.stacktrace);
+LightBright.enable();
+
+function somethingAsync () {
+  setTimeout(
+    () => {
+      throw new Error('I broke');
+    }, 10);
+}
+
+function callsSomethingAsync () {
+  somethingAsync();
+}
+
+callsSomethingAsync();
+
+process.on('uncaughtException', (e) => {
+  process._rawDebug('UncaughtException');
+  process._rawDebug(e);
+});
+

example/stacktrace/package.json

@@ -0,0 +1,30 @@
+{
+  "name": "stacktrace",
+  "version": "0.0.1",
+  "main": false,
+  "author": "Red Hat, Inc.",
+  "license": "Apache-2.0",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/bucharest-gold/lightbright.git"
+  },
+  "files": [
+    "package.json",
+    "LICENSE",
+    "index.js"
+  ],
+  "bugs": {
+    "url": "https://github.com/bucharest-gold/lightbright/issues"
+  },
+  "homepage": "https://github.com/bucharest-gold/lightbright/examples/stacktrace",
+  "description": "Example app showing usage of the LightBright.builtins.stacktrace filter",
+  "keywords": [
+    "trace",
+    "stack",
+    "stacktrace",
+    "async"
+  ],
+  "dependencies": {
+    "clarify": "~2.0.0"
+  }
+}

index.js

@@ -2,7 +2,8 @@
 
 const LightBright = require('./lib/trace_hooks');
 LightBright.builtins = {
-  timing: require('./lib/filters/timing')
+  timing: require('./lib/filters/timing'),
+  stacktrace: require('./lib/filters/stack-trace')
 };
 
 module.exports = exports = LightBright;

lib/filters/format.js

@@ -0,0 +1,59 @@
+// Copyright 2012 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+function FormatErrorString (error) {
+  try {
+    return Error.prototype.toString.call(error);
+  } catch (e) {
+    try {
+      return "<error: " + e + ">";
+    } catch (ee) {
+      return "<error>";
+    }
+  }
+}
+
+module.exports = function FormatStackTrace (error, frames) {
+  var lines = [];
+  lines.push(FormatErrorString(error));
+  for (var i = 0; i < frames.length; i++) {
+    var frame = frames[i];
+    var line;
+    try {
+      line = frame.toString();
+    } catch (e) {
+      try {
+        line = "<error: " + e + ">";
+      } catch (ee) {
+        // Any code that reaches this point is seriously nasty!
+        line = "<error>";
+      }
+    }
+    lines.push("    at " + line);
+  }
+  return lines.join("\n");
+};

lib/filters/stack-trace.js

@@ -0,0 +1,42 @@
+const chain = require('stack-chain');
+const stackFormatter = require('./format.js');
+const records = new WeakMap();
+let currentStack = null;
+
+Error.prepareStackTrace = function prepareStackTrace (err, stack) {
+  if (currentStack) stack.push.apply(stack, currentStack);
+  err.rawStack = stack;
+  return stackFormatter(err, stack);
+};
+
+function getCallSites (skip) {
+  const limit = Error.stackTraceLimit;
+
+  Error.stackTraceLimit = limit + skip;
+  const stack = chain.callSite({
+    extend: false,
+    filter: true,
+    slice: skip
+  });
+  Error.stackTraceLimit = limit;
+  return stack;
+}
+
+function tracer (record) {
+  switch (record.step) {
+    case 'init': {
+      records.set(record.handle, getCallSites(6));
+      break;
+    }
+    case 'pre': {
+      currentStack = records.get(record.handle);
+      break;
+    }
+    case 'post': {
+      currentStack = null;
+      break;
+    }
+  }
+}
+
+module.exports = exports = tracer;

package.json

@@ -37,5 +37,8 @@
     "type": "git",
     "url": "https://github.com/bucharest-gold/lightbright.git"
   },
-  "bugs": "https://github.com/bucharest-gold/lightbright/issues"
+  "bugs": "https://github.com/bucharest-gold/lightbright/issues",
+  "dependencies": {
+    "stack-chain": "~1.3.7"
+  }
 }