1 files changed, 209 insertions, 0 deletions
diff --git a/testing/modules/CoverageUtils.jsm b/testing/modules/CoverageUtils.jsm
new file mode 100644
index 000000000..0e36a767f
--- /dev/null
+++ b/testing/modules/CoverageUtils.jsm
@@ -0,0 +1,209 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = [
+  "CoverageCollector",
+]
+
+const Cc = Components.classes;
+const Ci = Components.interfaces;
+const Cu = Components.utils;
+
+const {TextEncoder, OS} = Cu.import("resource://gre/modules/osfile.jsm", {});
+const {addDebuggerToGlobal} = Cu.import("resource://gre/modules/jsdebugger.jsm",
+                                        {});
+addDebuggerToGlobal(this);
+
+/**
+ * Records coverage for each test by way of the js debugger.
+ */
+this.CoverageCollector = function (prefix) {
+  this._prefix = prefix;
+  this._dbg = new Debugger();
+  this._dbg.collectCoverageInfo = true;
+  this._dbg.addAllGlobalsAsDebuggees();
+  this._scripts = this._dbg.findScripts();
+
+  this._dbg.onNewScript = (script) => {
+    this._scripts.push(script);
+  };
+
+  // Source -> coverage data;
+  this._allCoverage = {};
+  this._encoder = new TextEncoder();
+  this._testIndex = 0;
+}
+
+CoverageCollector.prototype._getLinesCovered = function () {
+  let coveredLines = {};
+  let currentCoverage = {};
+  this._scripts.forEach(s => {
+    let scriptName = s.url;
+    let cov = s.getOffsetsCoverage();
+    if (!cov) {
+      return;
+    }
+
+    cov.forEach(covered => {
+      let {lineNumber, columnNumber, offset, count} = covered;
+      if (!count) {
+        return;
+      }
+
+      if (!currentCoverage[scriptName]) {
+        currentCoverage[scriptName] = {};
+      }
+      if (!this._allCoverage[scriptName]) {
+        this._allCoverage[scriptName] = {};
+      }
+
+      let key = [lineNumber, columnNumber, offset].join('#');
+      if (!currentCoverage[scriptName][key]) {
+        currentCoverage[scriptName][key] = count;
+      } else {
+        currentCoverage[scriptName][key] += count;
+      }
+    });
+
+  });
+
+  // Covered lines are determined by comparing every offset mentioned as of the
+  // the completion of a test to the last time we measured coverage. If an
+  // offset in a line is novel as of this test, or a count has increased for
+  // any offset on a particular line, that line must have been covered.
+  for (let scriptName in currentCoverage) {
+    for (let key in currentCoverage[scriptName]) {
+      if (!this._allCoverage[scriptName] ||
+          !this._allCoverage[scriptName][key] ||
+          (this._allCoverage[scriptName][key] <
+           currentCoverage[scriptName][key])) {
+        let [lineNumber, colNumber, offset] = key.split('#');
+        if (!coveredLines[scriptName]) {
+          coveredLines[scriptName] = new Set();
+        }
+        coveredLines[scriptName].add(parseInt(lineNumber, 10));
+        this._allCoverage[scriptName][key] = currentCoverage[scriptName][key];
+      }
+    }
+  }
+
+  return coveredLines;
+}
+
+CoverageCollector.prototype._getUncoveredLines = function() {
+  let uncoveredLines = {};
+  this._scripts.forEach(s => {
+    let scriptName = s.url;
+    let scriptOffsets = s.getAllOffsets();
+
+    if (!uncoveredLines[scriptName]){
+      uncoveredLines[scriptName] = new Set();
+    }
+
+    // Get all lines in the script
+    scriptOffsets.forEach( function(element, index) {
+      if (!element){
+        return;
+      }
+      uncoveredLines[scriptName].add(index);
+    });
+  });
+
+  // For all covered lines, delete their entry
+  for (let scriptName in this._allCoverage){
+    for (let key in this._allCoverage[scriptName]){
+      let [lineNumber, columnNumber, offset] = key.split('#');
+      uncoveredLines[scriptName].delete(parseInt(lineNumber, 10));
+    }
+  }
+
+  return uncoveredLines;
+}
+
+CoverageCollector.prototype._getMethodNames = function() {
+  let methodNames = {};
+  this._scripts.forEach(s => {
+    let method = s.displayName;
+    // If the method name is undefined, we return early
+    if (!method){
+      return;
+    }
+
+    let scriptName = s.url;
+    let tempMethodCov = [];
+    let scriptOffsets = s.getAllOffsets();
+
+    if (!methodNames[scriptName]){
+      methodNames[scriptName] = {};
+    }
+
+    /**
+    * Get all lines contained within the method and
+    * push a record of the form:
+    * <method name> : <lines covered>
+    */
+    scriptOffsets.forEach(function (element, index){
+      if (!element){
+        return;
+      }
+      tempMethodCov.push(index);
+    });
+    methodNames[scriptName][method] = tempMethodCov;
+  });
+
+  return methodNames;
+}
+
+/**
+ * Records lines covered since the last time coverage was recorded,
+ * associating them with the given test name. The result is written
+ * to a json file in a specified directory.
+ */
+CoverageCollector.prototype.recordTestCoverage = function (testName) {
+  dump("Collecting coverage for: " + testName + "\n");
+  let rawLines = this._getLinesCovered(testName);
+  let methods = this._getMethodNames();
+  let uncoveredLines = this._getUncoveredLines();
+  let result = [];
+  let versionControlBlock = {version: 1.0};
+  result.push(versionControlBlock);
+
+  for (let scriptName in rawLines) {
+    let rec = {
+      testUrl: testName,
+      sourceFile: scriptName,
+      methods: {},
+      covered: [],
+      uncovered: []
+    };
+
+    for (let methodName in methods[scriptName]){
+      rec.methods[methodName] = methods[scriptName][methodName];
+    }
+
+    for (let line of rawLines[scriptName]) {
+      rec.covered.push(line);
+    }
+
+    for (let line of uncoveredLines[scriptName]){
+      rec.uncovered.push(line);
+    }
+
+    result.push(rec);
+  }
+  let arr = this._encoder.encode(JSON.stringify(result, null, 2));
+  let path = this._prefix + '/' + 'jscov_' + Date.now() + '.json';
+  dump("Writing coverage to: " + path + "\n");
+  return OS.File.writeAtomic(path, arr, {tmpPath: path + '.tmp'});
+}
+
+/**
+ * Tear down the debugger after all tests are complete.
+ */
+CoverageCollector.prototype.finalize = function () {
+  this._dbg.removeAllDebuggees();
+  this._dbg.enabled = false;
+}