Issue checkstyle#37: inject, invoke maven command, read file and clea…

…n up

config/findbugs-exclude.xml

@@ -9,7 +9,10 @@
     <Match>
         <!-- This is a false positive. It is no problem to do that cast. In fact the cast is
             in JGit library. There is no reason to raise this warning. -->
-        <Class name="com.github.checkstyle.regression.git.DiffParser"/>
+        <Or>
+            <Class name="com.github.checkstyle.regression.git.DiffParser"/>
+            <Class name="com.github.checkstyle.regression.extract.CheckstyleInjector"/>
+        </Or>
         <Or>
             <Bug pattern="BC_UNCONFIRMED_CAST"/>
             <Bug pattern="BC_UNCONFIRMED_CAST_OF_RETURN_VALUE"/>

config/import-control.xml

@@ -5,6 +5,8 @@
 
 <import-control pkg="com.github.checkstyle.regression">
     <allow pkg="java.io"/>
+    <allow pkg="java.nio"/>
+    <allow pkg="org.apache.commons.io"/>
     <allow pkg="java.util"/>
     <allow pkg="com.github.checkstyle.regression.data"/>
     <allow pkg="org.immutables.value"/>
@@ -13,7 +15,6 @@
         <allow pkg="javax.xml"/>
         <allow pkg="org.w3c.dom"/>
         <allow pkg="org.xml"/>
-        <allow pkg="java.nio"/>
     </subpackage>
 
     <subpackage name="data">
@@ -25,6 +26,8 @@
         <allow pkg="com.google.gson"/>
         <allow class="com.sun.tools.javac.util.ServiceLoader"/>
         <allow class="java.lang.reflect.Type"/>
+        <!-- we need to run Git checkout command. -->
+        <allow pkg="org.eclipse.jgit"/>
     </subpackage>
 
     <subpackage name="git">

pom.xml

@@ -288,7 +288,17 @@
                                     <regex>
                                         <pattern>com.github.checkstyle.regression.configuration.ConfigGenerator</pattern>
                                         <branchRate>80</branchRate>
-                                        <lineRate>91</lineRate>
+                                        <lineRate>92</lineRate>
+                                    </regex>
+                                    <regex>
+                                        <pattern>com.github.checkstyle.regression.extract.ExtractInfoProcessor</pattern>
+                                        <branchRate>100</branchRate>
+                                        <lineRate>66</lineRate>
+                                    </regex>
+                                    <regex>
+                                        <pattern>com.github.checkstyle.regression.extract.CheckstyleInjector</pattern>
+                                        <branchRate>0</branchRate>
+                                        <lineRate>0</lineRate>
                                     </regex>
                                     <regex>
                                         <pattern>com.github.checkstyle.regression.module.ModuleUtils</pattern>

src/main/java/com/github/checkstyle/regression/extract/CheckstyleInjector.java

@@ -0,0 +1,140 @@
+////////////////////////////////////////////////////////////////////////////////
+// checkstyle: Checks Java source code for adherence to a set of rules.
+// Copyright (C) 2001-2017 the original author or authors.
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+////////////////////////////////////////////////////////////////////////////////
+
+package com.github.checkstyle.regression.extract;
+
+import java.io.Closeable;
+import java.io.File;
+import java.io.IOException;
+
+import org.apache.commons.io.FileUtils;
+import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.api.errors.GitAPIException;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
+
+/**
+ * Injects files to checkstyle repository, which would be invoked by maven command
+ * to generate module extract info.
+ * @author LuoLiangchen
+ */
+final class CheckstyleInjector implements Closeable {
+    /** The path to checkstyle repository. */
+    private final String repoPath;
+
+    /** The name of PR branch. */
+    private final String branch;
+
+    /** The checkstyle repository. */
+    private final Repository repository;
+
+    /**
+     * Creates a new instance of CheckstyleInjector.
+     * @param repoPath the path to checkstyle repository
+     * @param branch   the name of PR branch
+     */
+    CheckstyleInjector(String repoPath, String branch) {
+        this.repoPath = repoPath;
+        this.branch = branch;
+
+        final File gitDir = new File(repoPath, ".git");
+        final Repository repo;
+        try {
+            repo = new FileRepositoryBuilder().setGitDir(gitDir)
+                    .readEnvironment().findGitDir().build();
+        }
+        catch (IOException ex) {
+            throw new IllegalStateException(ex);
+        }
+        repository = repo;
+    }
+
+    /**
+     * Generates the module extract info file.
+     * @return the module extract info file
+     * @throws IOException     failure of generation
+     * @throws GitAPIException JGit library exception
+     */
+    public File generateExtractInfoFile() throws IOException, GitAPIException {
+        checkoutToPrBranch();
+        copyInjectFilesToCheckstyleRepo();
+        invokeMavenCommand();
+        return null;
+    }
+
+    /**
+     * Clears the injected files and the generated info file in checkstyle repository.
+     * @throws GitAPIException JGit library exception
+     */
+    public void clearInjections() throws GitAPIException {
+        final Git git = new Git(repository);
+
+        try {
+            git.checkout().addPath(".").call();
+        }
+        finally {
+            git.close();
+        }
+    }
+
+    /** Closes the repository resource. */
+    @Override
+    public void close() {
+        repository.close();
+    }
+
+    /**
+     * Invokes Maven command to generate the extract info file in checkstyle repository.
+     */
+    private static void invokeMavenCommand() {
+        // invoke maven command to generate the extract info file
+    }
+
+    /**
+     * Copies the injection files to checkstyle repository.
+     * @throws IOException failure of copying
+     */
+    private void copyInjectFilesToCheckstyleRepo() throws IOException {
+        final File srcDir =
+                new File("src/main/resources/com/github/checkstyle/regression/extract/");
+        final File destDir = new File(repoPath, "src/test/java/com/puppycrawl/tools/checkstyle/");
+        final String[] injections = {"ExtractInfoGeneratorTest.java", "Json.java"};
+        for (String injection : injections) {
+            final File srcFile = new File(srcDir, injection);
+            final File destFile = new File(destDir, injection);
+            FileUtils.copyFile(srcFile, destFile);
+        }
+    }
+
+    /**
+     * Checkouts to the PR branch in the given repository.
+     * @throws GitAPIException JGit library exception
+     */
+    private void checkoutToPrBranch()
+            throws GitAPIException {
+        final Git git = new Git(repository);
+
+        try {
+            git.checkout().setName(branch).call();
+        }
+        finally {
+            git.close();
+        }
+    }
+}

src/main/java/com/github/checkstyle/regression/extract/ExtractInfoProcessor.java

@@ -19,13 +19,19 @@
 
 package com.github.checkstyle.regression.extract;
 
+import java.io.File;
+import java.io.FileInputStream;
 import java.io.IOException;
+import java.io.InputStreamReader;
 import java.io.Reader;
 import java.lang.reflect.Type;
+import java.nio.charset.Charset;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
 
+import org.eclipse.jgit.api.errors.GitAPIException;
+
 import com.github.checkstyle.regression.data.ModuleExtractInfo;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
@@ -57,13 +63,40 @@ private ExtractInfoProcessor() {
         GSON = gsonBuilder.create();
     }
 
+    /**
+     * Gets the module extract info map from the given branch of checkstyle repository.
+     * @param repoPath the path of checkstyle repository
+     * @param branch   the given branch on which to generate the extract info
+     * @return the full qualified name to module extract info map
+     * @throws IOException     failure when creating or reading the info file
+     * @throws GitAPIException failure when running Git command
+     */
+    public static Map<String, ModuleExtractInfo> getModuleExtractInfos(
+            String repoPath, String branch) throws IOException, GitAPIException {
+        final Map<String, ModuleExtractInfo> returnValue;
+        final CheckstyleInjector injector = new CheckstyleInjector(repoPath, branch);
+
+        try {
+            final File file = injector.generateExtractInfoFile();
+            final Reader reader = new InputStreamReader(
+                    new FileInputStream(file), Charset.forName("UTF-8"));
+            returnValue = getModuleExtractInfosFromReader(reader);
+        }
+        finally {
+            injector.clearInjections();
+            injector.close();
+        }
+
+        return returnValue;
+    }
+
     /**
      * Gets the module extract info map from the given reader. Map key is the
      * fully qualified module name.
      * @param reader the given reader
      * @return the full qualified name to module extract info map
      */
-    public static Map<String, ModuleExtractInfo> getModuleExtractInfosFromReader(
+    private static Map<String, ModuleExtractInfo> getModuleExtractInfosFromReader(
             Reader reader) {
         final List<ModuleExtractInfo> modules;
 

src/test/java/com/github/checkstyle/regression/extract/ExtractInfoProcessorTest.java

@@ -28,9 +28,13 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.io.Reader;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
 import java.nio.charset.Charset;
 import java.util.Map;
 
+import org.junit.Before;
 import org.junit.Test;
 
 import com.github.checkstyle.regression.data.ImmutableModuleExtractInfo;
@@ -39,18 +43,26 @@
 public class ExtractInfoProcessorTest {
     private static final String BASE_PACKAGE = "com.puppycrawl.tools.checkstyle";
 
+    private Method getModuleExtractInfosFromReaderMethod;
+
+    @Before
+    public void setUp() throws Exception {
+        getModuleExtractInfosFromReaderMethod = ExtractInfoProcessor.class
+                .getDeclaredMethod("getModuleExtractInfosFromReader", Reader.class);
+        getModuleExtractInfosFromReaderMethod.setAccessible(true);
+    }
+
     @Test
     public void testIsProperUtilsClass() throws Exception {
         assertUtilsClassHasPrivateConstructor(ExtractInfoProcessor.class);
     }
 
     @Test
-    public void testGetModuleExtractInfosFromReader() {
+    public void testGetModuleExtractInfosFromReader() throws Exception {
         final InputStream is = ExtractInfoProcessor.class.getClassLoader()
                 .getResourceAsStream("checkstyle_modules.json");
         final InputStreamReader reader = new InputStreamReader(is, Charset.forName("UTF-8"));
-        final Map<String, ModuleExtractInfo> map =
-                ExtractInfoProcessor.getModuleExtractInfosFromReader(reader);
+        final Map<String, ModuleExtractInfo> map = getModuleExtractInfosFromReader(reader);
 
         final String module1 = "NewlineAtEndOfFileCheck";
         final ModuleExtractInfo extractInfo1 = ImmutableModuleExtractInfo.builder()
@@ -79,14 +91,21 @@ public void testGetNameToModuleInfoFromInputStreamWithException() throws Excepti
         doThrow(IOException.class).when(is).close();
 
         try {
-            ExtractInfoProcessor.getModuleExtractInfosFromReader(reader);
+            getModuleExtractInfosFromReader(reader);
             fail("Exception is expected");
         }
-        catch (IllegalStateException ex) {
+        catch (InvocationTargetException ex) {
             assertEquals(
                     "Exception message is wrong",
                     "Failed when loaing hardcoded checkstyle module information",
-                    ex.getMessage());
+                    ex.getTargetException().getMessage());
         }
     }
+
+    @SuppressWarnings("unchecked")
+    private Map<String, ModuleExtractInfo> getModuleExtractInfosFromReader(Reader reader)
+            throws Exception {
+        return (Map<String, ModuleExtractInfo>) getModuleExtractInfosFromReaderMethod
+                .invoke(ExtractInfoProcessor.class, reader);
+    }
 }

src/test/java/com/github/checkstyle/regression/module/ModuleInfoCollectorTest.java

@@ -24,6 +24,8 @@
 
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.io.Reader;
+import java.lang.reflect.Method;
 import java.nio.charset.Charset;
 import java.util.Arrays;
 import java.util.LinkedList;
@@ -51,13 +53,17 @@ public class ModuleInfoCollectorTest {
     private static final String JAVA_TEST_SOURCE_PREFIX =
             "src/test/java/com/puppycrawl/tools/checkstyle/";
 
+    @SuppressWarnings("unchecked")
     @Before
-    public void setUp() {
+    public void setUp() throws Exception {
         final InputStream is = ExtractInfoProcessor.class.getClassLoader()
                 .getResourceAsStream("checkstyle_modules.json");
         final InputStreamReader reader = new InputStreamReader(is, Charset.forName("UTF-8"));
+        final Method method = ExtractInfoProcessor.class
+                .getDeclaredMethod("getModuleExtractInfosFromReader", Reader.class);
+        method.setAccessible(true);
         final Map<String, ModuleExtractInfo> map =
-                ExtractInfoProcessor.getModuleExtractInfosFromReader(reader);
+                (Map<String, ModuleExtractInfo>) method.invoke(ExtractInfoProcessor.class, reader);
         ModuleUtils.setNameToModuleExtractInfo(map);
     }
 

src/test/java/com/github/checkstyle/regression/module/ModuleUtilsTest.java

@@ -26,6 +26,8 @@
 
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.io.Reader;
+import java.lang.reflect.Method;
 import java.nio.charset.Charset;
 import java.util.Map;
 
@@ -44,13 +46,17 @@ public class ModuleUtilsTest {
     private static final String JAVA_MAIN_SOURCE_PREFIX =
             "src/main/java/com/puppycrawl/tools/checkstyle/";
 
+    @SuppressWarnings("unchecked")
     @Before
-    public void setUp() {
+    public void setUp() throws Exception {
         final InputStream is = ExtractInfoProcessor.class.getClassLoader()
                 .getResourceAsStream("checkstyle_modules.json");
         final InputStreamReader reader = new InputStreamReader(is, Charset.forName("UTF-8"));
+        final Method method = ExtractInfoProcessor.class
+                .getDeclaredMethod("getModuleExtractInfosFromReader", Reader.class);
+        method.setAccessible(true);
         final Map<String, ModuleExtractInfo> map =
-                ExtractInfoProcessor.getModuleExtractInfosFromReader(reader);
+                (Map<String, ModuleExtractInfo>) method.invoke(ExtractInfoProcessor.class, reader);
         ModuleUtils.setNameToModuleExtractInfo(map);
     }