Add checkstyle formatter

src/formatters/checkstyleFormatter.ts

@@ -0,0 +1,33 @@
+import {AbstractFormatter} from "../language/formatter/abstractFormatter";
+import {RuleFailure} from "../language/rule/rule";
+
+export class Formatter extends AbstractFormatter {
+    public format(failures: RuleFailure[]): string {
+        let output = '<?xml version="1.0" encoding="utf-8"?><checkstyle version="4.3">';
+
+        if (failures.length) {
+            output += `<file name="${this.escapeXml(failures[0].getFileName())}">`;
+            for (let failure of failures) {
+                output += `<error line="${failure.getStartPosition().getLineAndCharacter().line + 1}" `;
+                output += `column="${failure.getStartPosition().getLineAndCharacter().character + 1}" `;
+                output += `severity="warning" `;
+                output += `message="${this.escapeXml(failure.getFailure())}" `;
+                // checkstyle parser wants "source" to have structure like <anything>dot<category>dot<type>
+                output += `source="failure.tslint.${this.escapeXml(failure.getRuleName())}" />`;
+            }
+            output += "</file>";
+        }
+
+        output += "</checkstyle>";
+        return output;
+    }
+
+    private escapeXml(str: string): string {
+        return str
+            .replace(/&/g, "&amp;")
+            .replace(/</g, "&lt;")
+            .replace(/>/g, "&gt;")
+            .replace(/'/g, "&#39;")
+            .replace(/"/g, "&quot;");
+    }
+}

src/tsconfig.json

@@ -42,6 +42,7 @@
         "tslint-cli.ts",
         "tslint.ts",
         "utils.ts",
+        "formatters/checkstyleFormatter.ts",
         "formatters/index.ts",
         "formatters/jsonFormatter.ts",
         "formatters/msbuildFormatter.ts",

test/formatters/checkstyleFormatterTests.ts

@@ -0,0 +1,40 @@
+import * as ts from "typescript";
+import {IFormatter, RuleFailure, TestUtils} from "../lint";
+
+describe("Checkstyle Formatter", () => {
+    const TEST_FILE = "formatters/pmdFormatter.test.ts"; // reuse existing sample file
+    let sourceFile: ts.SourceFile;
+    let formatter: IFormatter;
+
+    before(() => {
+        const Formatter = TestUtils.getFormatter("checkstyle");
+        sourceFile = TestUtils.getSourceFile(TEST_FILE);
+        formatter = new Formatter();
+    });
+
+    it("formats failures", () => {
+        const maxPosition = sourceFile.getFullWidth();
+
+        const failures = [
+            new RuleFailure(sourceFile, 0, 1, "first failure", "first-name"),
+            new RuleFailure(sourceFile, 2, 3, "&<>'\" should be escaped", "escape"),
+            new RuleFailure(sourceFile, maxPosition - 1, maxPosition, "last failure", "last-name"),
+        ];
+        const expectedResult =
+            '<?xml version="1.0" encoding="utf-8"?><checkstyle version="4.3">' +
+            `<file name="${TEST_FILE}">` +
+            '<error line="1" column="1" severity="warning" message="first failure" source="failure.tslint.first-name" />' +
+            '<error line="1" column="3" severity="warning" message="&amp;&lt;&gt;&#39;&quot; should be escaped" ' +
+            'source="failure.tslint.escape" />' +
+            '<error line="6" column="3" severity="warning" message="last failure" source="failure.tslint.last-name" />' +
+            "</file>" +
+            "</checkstyle>";
+
+        assert.equal(formatter.format(failures), expectedResult);
+    });
+
+    it("handles no failures", () => {
+        const result = formatter.format([]);
+        assert.deepEqual(result, '<?xml version="1.0" encoding="utf-8"?><checkstyle version="4.3"></checkstyle>');
+    });
+});

test/tsconfig.json

@@ -36,6 +36,7 @@
         "../src/enableDisableRules.ts",
         "../src/formatterLoader.ts",
         "../src/formatters.ts",
+        "../src/formatters/checkstyleFormatter.ts",
         "../src/formatters/index.ts",
         "../src/formatters/jsonFormatter.ts",
         "../src/formatters/msbuildFormatter.ts",
@@ -132,6 +133,7 @@
         "ruleTestRunner.ts",
         "utils.ts",
         "utilsTests.ts",
+        "formatters/checkstyleFormatterTests.ts",
         "formatters/externalFormatterTest.ts",
         "formatters/jsonFormatterTests.ts",
         "formatters/msbuildFormatterTests.ts",