Avoid removing target/classes dir during IC in Maven

#KT-21581 fixed

libraries/tools/kotlin-maven-plugin-test/src/test/java/org.jetbrains.kotlin.maven/IncrementalCompilationIT.java

@@ -9,7 +9,8 @@ public class IncrementalCompilationIT extends MavenITBase {
         MavenProject project = new MavenProject("kotlinSimple");
         project.exec("package")
                .succeeded()
-               .compiledKotlin("src/A.kt", "src/useA.kt", "src/Dummy.kt");
+               .fileExists("target/classes/test.properties")
+               .compiledKotlin("src/main/kotlin/A.kt", "src/main/kotlin/useA.kt", "src/main/kotlin/Dummy.kt");
     }
 
     @Test
@@ -27,7 +28,7 @@ public class IncrementalCompilationIT extends MavenITBase {
         MavenProject project = new MavenProject("kotlinSimple");
         project.exec("package");
 
-        File aKt = project.file("src/A.kt");
+        File aKt = project.file("src/main/kotlin/A.kt");
         String original = "class A";
         String replacement = "private class A";
         MavenTestUtils.replaceFirstInFile(aKt, original, replacement);
@@ -39,7 +40,7 @@ public class IncrementalCompilationIT extends MavenITBase {
         MavenTestUtils.replaceFirstInFile(aKt, replacement, original);
         project.exec("package")
                .succeeded()
-               .compiledKotlin("src/A.kt", "src/useA.kt");
+               .compiledKotlin("src/main/kotlin/A.kt", "src/main/kotlin/useA.kt");
 
     }
 
@@ -48,12 +49,12 @@ public class IncrementalCompilationIT extends MavenITBase {
         MavenProject project = new MavenProject("kotlinSimple");
         project.exec("package");
 
-        File aKt = project.file("src/A.kt");
+        File aKt = project.file("src/main/kotlin/A.kt");
         MavenTestUtils.replaceFirstInFile(aKt, "fun foo", "internal fun foo");
 
         project.exec("package")
                .succeeded()
-               .compiledKotlin("src/A.kt", "src/useA.kt");
+               .compiledKotlin("src/main/kotlin/A.kt", "src/main/kotlin/useA.kt");
 
         // todo rebuild and compare output
     }

libraries/tools/kotlin-maven-plugin-test/src/test/java/org.jetbrains.kotlin.maven/MavenExecutionResult.java

@@ -110,4 +110,14 @@ class MavenExecutionResult {
             }
         });
     }
+
+    MavenExecutionResult fileExists(@NotNull final String path) throws Exception {
+        return check(new Action<MavenExecutionResult>() {
+            @Override
+            public void run(MavenExecutionResult execResult) {
+                File file = new File(workingDir, path);
+                Assert.assertTrue(file + " does not exist", file.exists());
+            }
+        });
+    }
 }

libraries/tools/kotlin-maven-plugin-test/src/test/resources/kotlinSimple/pom.xml

@@ -21,6 +21,8 @@
     </dependencies>
 
     <build>
+        <sourceDirectory>${project.basedir}/src/main/kotlin</sourceDirectory>
+
         <pluginManagement>
             <plugins>
                 <plugin>
@@ -40,7 +42,6 @@
             </plugins>
         </pluginManagement>
 
-        <sourceDirectory>${project.basedir}/src</sourceDirectory>
         <plugins>
             <plugin>
                 <artifactId>kotlin-maven-plugin</artifactId>

libraries/tools/kotlin-maven-plugin-test/src/test/resources/kotlinSimple/src/main/resources/test.properties

@@ -0,0 +1 @@
+example.property=101

libraries/tools/kotlin-maven-plugin/src/main/java/org/jetbrains/kotlin/maven/K2JVMCompileMojo.java

@@ -16,7 +16,9 @@
 
 package org.jetbrains.kotlin.maven;
 
+import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.PsiJavaModule;
+import kotlin.collections.MapsKt;
 import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugin.MojoFailureException;
 import org.apache.maven.plugins.annotations.LifecyclePhase;
@@ -32,15 +34,15 @@ import org.jetbrains.kotlin.cli.common.arguments.K2JVMCompilerArguments;
 import org.jetbrains.kotlin.cli.common.messages.MessageCollector;
 import org.jetbrains.kotlin.cli.jvm.K2JVMCompiler;
 import org.jetbrains.kotlin.incremental.IncrementalJvmCompilerRunnerKt;
+import org.jetbrains.kotlin.maven.incremental.FileCopier;
 import org.jetbrains.kotlin.maven.incremental.MavenICReporter;
 import org.jetbrains.kotlin.maven.kapt.AnnotationProcessingManager;
 
-import java.io.File;
-import java.io.IOException;
+import java.io.*;
 import java.net.URL;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
+import java.nio.file.*;
+import java.util.*;
+import java.util.stream.Collectors;
 
 import static com.intellij.openapi.util.text.StringUtil.join;
 import static org.jetbrains.kotlin.maven.Util.filterClassPath;
@@ -241,19 +243,43 @@ public class K2JVMCompileMojo extends KotlinCompileMojoBase<K2JVMCompilerArgumen
         File cachesDir = getCachesDir();
         //noinspection ResultOfMethodCallIgnored
         cachesDir.mkdirs();
-
+        String destination = arguments.getDestination();
+        assert destination != null : "output is not specified!";
+        File classesDir = new File(destination);
+        File kotlinClassesDir = new File(cachesDir, "classes");
+        File snapshotsFile = new File(cachesDir, "snapshots.bin");
+        String classpath = arguments.getClasspath();
         MavenICReporter icReporter = MavenICReporter.get(getLog());
 
         try {
+            arguments.setDestination(kotlinClassesDir.getAbsolutePath());
+            if (classpath != null) {
+                List<String> filteredClasspath = new ArrayList<>();
+                for (String path : classpath.split(File.pathSeparator)) {
+                    if (!classesDir.equals(new File(path))) {
+                        filteredClasspath.add(path);
+                    }
+                }
+                arguments.setClasspath(StringUtil.join(filteredClasspath, File.pathSeparator));
+            }
+
             IncrementalJvmCompilerRunnerKt.makeIncrementally(cachesDir, sourceRoots, arguments, messageCollector, icReporter);
 
             int compiledKtFilesCount = icReporter.getCompiledKotlinFiles().size();
             getLog().info("Compiled " + icReporter.getCompiledKotlinFiles().size() + " Kotlin files using incremental compiler");
+
+            if (!messageCollector.hasErrors()) {
+                (new FileCopier(getLog())).syncDirs(kotlinClassesDir, classesDir, snapshotsFile);
+            }
         }
         catch (Throwable t) {
             t.printStackTrace();
             return ExitCode.INTERNAL_ERROR;
         }
+        finally {
+            arguments.setDestination(destination);
+            arguments.setClasspath(classpath);
+        }
 
         if (messageCollector.hasErrors()) {
             return ExitCode.COMPILATION_ERROR;

libraries/tools/kotlin-maven-plugin/src/main/java/org/jetbrains/kotlin/maven/incremental/FileCopier.java

@@ -0,0 +1,147 @@
+/*
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license 
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.maven.incremental;
+
+import org.apache.maven.plugin.logging.Log;
+import org.jetbrains.annotations.NotNull;
+
+import java.io.*;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+public class FileCopier {
+    private final static int VERSION = 0;
+
+    private final Log log;
+
+    public FileCopier(Log log) {
+        this.log = log;
+    }
+
+    public void syncDirs(@NotNull File from, @NotNull File to, @NotNull File snapshotsStorageFile) {
+        try {
+            syncDirsImpl(from, to, snapshotsStorageFile);
+        } catch (IOException e) {
+            log.warn("Could not copy Kotlin files from " + from + " to " + to, e);
+        }
+    }
+
+    private void syncDirsImpl(
+            @NotNull File sourceBaseFile,
+            @NotNull File targetBaseFile,
+            @NotNull File snapshotsStorageFile
+    ) throws IOException {
+        // snapshots are stored as relative paths (to source or target base)
+        Map<String, FileSnapshot> previousSnapshots = readFileSnapshots(snapshotsStorageFile);
+
+        Path sourceBase = Paths.get(sourceBaseFile.getPath()).normalize();
+        Path targetBase = Paths.get(targetBaseFile.getPath()).normalize();
+        Map<String, FileSnapshot> newSnapshots = new HashMap<>();
+        for (Path path : Files.walk(sourceBase).collect(Collectors.toList())) {
+            if (!Files.isRegularFile(path)) continue;
+
+            String relativePath = sourceBase.relativize(path).toString();
+
+            File file = path.toFile();
+            FileSnapshot snapshot = new FileSnapshot(file.lastModified(), file.length());
+
+            // remove current files from previousSnapshots map so only removed files would remain in previousSnapshots
+            FileSnapshot prevSnapshot = previousSnapshots.remove(relativePath);
+            if (!snapshot.equals(prevSnapshot)) {
+                Path target = targetBase.resolve(relativePath);
+                if (!Files.isDirectory(target)) {
+                    Files.deleteIfExists(target);
+                    Files.createDirectories(target.getParent());
+                    Files.copy(path, target);
+                }
+
+                log.debug("Copied " + path + " to " + target);
+            }
+            newSnapshots.put(relativePath, snapshot);
+        }
+
+        for (String removedPath : previousSnapshots.keySet()) {
+            Path target = targetBase.resolve(removedPath);
+            log.debug("Deleted " + target + " as it is no longer present in " + sourceBase);
+            if (Files.isRegularFile(target)) {
+                Files.delete(target);
+            }
+        }
+
+        writeFileSnapshots(newSnapshots, snapshotsStorageFile);
+    }
+
+    private void writeFileSnapshots(@NotNull Map<String, FileSnapshot> snapshots, @NotNull File outputFile) {
+        try (ObjectOutputStream output = new ObjectOutputStream(new BufferedOutputStream(new FileOutputStream(outputFile)))) {
+            output.writeInt(VERSION);
+            output.writeInt(snapshots.size());
+            for (Map.Entry<String, FileSnapshot> entry : snapshots.entrySet()) {
+                String path = entry.getKey();
+                output.writeUTF(path);
+                FileSnapshot snapshot = entry.getValue();
+                output.writeLong(snapshot.lastModified);
+                output.writeLong(snapshot.size);
+            }
+        } catch (Exception e) {
+            log.debug("Couldn't write copied files list to " + outputFile, e);
+        }
+    }
+
+    @NotNull
+    private Map<String, FileSnapshot> readFileSnapshots(@NotNull File inputFile) {
+        Map<String, FileSnapshot> snapshots = new HashMap<>();
+        if (!inputFile.isFile()) return snapshots;
+
+        try (ObjectInputStream input  = new ObjectInputStream(new BufferedInputStream(new FileInputStream(inputFile)))) {
+            int version = input.readInt();
+            if (version != VERSION) return snapshots;
+
+            int size = input.readInt();
+            for (int i = 0; i < size; i++) {
+                String path = input.readUTF();
+                long lastModified = input.readLong();
+                long fileSize = input.readLong();
+                snapshots.put(path, new FileSnapshot(lastModified, fileSize));
+            }
+        } catch (Exception e) {
+            log.debug("Couldn't read copied files list from " + inputFile, e);
+        }
+
+        return snapshots;
+    }
+
+    private static class FileSnapshot {
+        final long lastModified;
+        final long size;
+
+        private FileSnapshot(long lastModified, long size) {
+            this.lastModified = lastModified;
+            this.size = size;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+
+            FileSnapshot that = (FileSnapshot) o;
+
+            if (lastModified != that.lastModified) return false;
+            return size == that.size;
+        }
+
+        @Override
+        public int hashCode() {
+            int result = (int) (lastModified ^ (lastModified >>> 32));
+            result = 31 * result + (int) (size ^ (size >>> 32));
+            return result;
+        }
+    }
+}