1 files changed, 306 insertions, 0 deletions
diff --git a/java/com/google/gerrit/pgm/rules/PrologCompiler.java b/java/com/google/gerrit/pgm/rules/PrologCompiler.java
new file mode 100644
index 0000000000..2663f42f51
--- /dev/null
+++ b/java/com/google/gerrit/pgm/rules/PrologCompiler.java
@@ -0,0 +1,306 @@
+// Copyright (C) 2011 The Android Open Source Project
+//
+// 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.
+
+package com.google.gerrit.pgm.rules;
+
+import com.google.gerrit.common.Version;
+import com.google.gerrit.reviewdb.client.RefNames;
+import com.google.gerrit.server.config.GerritServerConfig;
+import com.google.gerrit.server.config.SitePaths;
+import com.google.gerrit.server.util.time.TimeUtil;
+import com.google.inject.Inject;
+import com.google.inject.assistedinject.Assisted;
+import com.googlecode.prolog_cafe.compiler.Compiler;
+import com.googlecode.prolog_cafe.exceptions.CompileException;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+import java.util.concurrent.Callable;
+import java.util.jar.Attributes;
+import java.util.jar.JarEntry;
+import java.util.jar.JarOutputStream;
+import java.util.jar.Manifest;
+import javax.tools.Diagnostic;
+import javax.tools.DiagnosticCollector;
+import javax.tools.JavaCompiler;
+import javax.tools.JavaFileObject;
+import javax.tools.StandardJavaFileManager;
+import javax.tools.ToolProvider;
+import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.lib.Config;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.Repository;
+
+/**
+ * Helper class for Rulec: does the actual prolog -> java src -> class -> jar work Finds rules.pl in
+ * refs/meta/config branch Creates rules-(sha1 of rules.pl).jar in (site-path)/cache/rules
+ */
+public class PrologCompiler implements Callable<PrologCompiler.Status> {
+  public interface Factory {
+    PrologCompiler create(Repository git);
+  }
+
+  public enum Status {
+    NO_RULES,
+    COMPILED
+  }
+
+  private final Path ruleDir;
+  private final Repository git;
+
+  @Inject
+  PrologCompiler(
+      @GerritServerConfig Config config, SitePaths site, @Assisted Repository gitRepository) {
+    Path cacheDir = site.resolve(config.getString("cache", null, "directory"));
+    ruleDir = cacheDir != null ? cacheDir.resolve("rules") : null;
+    git = gitRepository;
+  }
+
+  @Override
+  public Status call() throws IOException, CompileException {
+    ObjectId metaConfig = git.resolve(RefNames.REFS_CONFIG);
+    if (metaConfig == null) {
+      return Status.NO_RULES;
+    }
+
+    ObjectId rulesId = git.resolve(metaConfig.name() + ":rules.pl");
+    if (rulesId == null) {
+      return Status.NO_RULES;
+    }
+
+    if (ruleDir == null) {
+      throw new CompileException("Caching not enabled");
+    }
+    Files.createDirectories(ruleDir);
+
+    File tempDir = File.createTempFile("GerritCodeReview_", ".rulec");
+    if (!tempDir.delete() || !tempDir.mkdir()) {
+      throw new IOException("Cannot create " + tempDir);
+    }
+    try {
+      // Try to make the directory accessible only by this process.
+      // This may help to prevent leaking rule data to outsiders.
+      tempDir.setReadable(true, true);
+      tempDir.setWritable(true, true);
+      tempDir.setExecutable(true, true);
+
+      compileProlog(rulesId, tempDir);
+      compileJava(tempDir);
+
+      Path jarPath = ruleDir.resolve("rules-" + rulesId.getName() + ".jar");
+      List<String> classFiles = getRelativePaths(tempDir, ".class");
+      createJar(jarPath, classFiles, tempDir, metaConfig, rulesId);
+
+      return Status.COMPILED;
+    } finally {
+      deleteAllFiles(tempDir);
+    }
+  }
+
+  /** Creates a copy of rules.pl and compiles it into Java sources. */
+  private void compileProlog(ObjectId prolog, File tempDir) throws IOException, CompileException {
+    File tempRules = copyToTempFile(prolog, tempDir);
+    try {
+      Compiler comp = new Compiler();
+      comp.prologToJavaSource(tempRules.getPath(), tempDir.getPath());
+    } finally {
+      tempRules.delete();
+    }
+  }
+
+  private File copyToTempFile(ObjectId blobId, File tempDir)
+      throws IOException, FileNotFoundException, MissingObjectException {
+    // Any leak of tmp caused by this method failing will be cleaned
+    // up by our caller when tempDir is recursively deleted.
+    File tmp = File.createTempFile("rules", ".pl", tempDir);
+    try (OutputStream out = Files.newOutputStream(tmp.toPath())) {
+      git.open(blobId).copyTo(out);
+    }
+    return tmp;
+  }
+
+  /** Compile java src into java .class files */
+  private void compileJava(File tempDir) throws IOException, CompileException {
+    JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
+    if (compiler == null) {
+      throw new CompileException("JDK required (running inside of JRE)");
+    }
+
+    DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<>();
+    try (StandardJavaFileManager fileManager =
+        compiler.getStandardFileManager(diagnostics, null, null)) {
+      Iterable<? extends JavaFileObject> compilationUnits =
+          fileManager.getJavaFileObjectsFromFiles(getAllFiles(tempDir, ".java"));
+      ArrayList<String> options = new ArrayList<>();
+      String classpath = getMyClasspath();
+      if (classpath != null) {
+        options.add("-classpath");
+        options.add(classpath);
+      }
+      options.add("-d");
+      options.add(tempDir.getPath());
+      JavaCompiler.CompilationTask task =
+          compiler.getTask(null, fileManager, diagnostics, options, null, compilationUnits);
+      if (!task.call()) {
+        Locale myLocale = Locale.getDefault();
+        StringBuilder msg = new StringBuilder();
+        msg.append("Cannot compile to Java bytecode:");
+        for (Diagnostic<? extends JavaFileObject> err : diagnostics.getDiagnostics()) {
+          msg.append('\n');
+          msg.append(err.getKind());
+          msg.append(": ");
+          if (err.getSource() != null) {
+            msg.append(err.getSource().getName());
+          }
+          msg.append(':');
+          msg.append(err.getLineNumber());
+          msg.append(": ");
+          msg.append(err.getMessage(myLocale));
+        }
+        throw new CompileException(msg.toString());
+      }
+    }
+  }
+
+  private String getMyClasspath() {
+    StringBuilder cp = new StringBuilder();
+    appendClasspath(cp, getClass().getClassLoader());
+    return 0 < cp.length() ? cp.toString() : null;
+  }
+
+  private void appendClasspath(StringBuilder cp, ClassLoader classLoader) {
+    if (classLoader.getParent() != null) {
+      appendClasspath(cp, classLoader.getParent());
+    }
+    if (classLoader instanceof URLClassLoader) {
+      for (URL url : ((URLClassLoader) classLoader).getURLs()) {
+        if ("file".equals(url.getProtocol())) {
+          if (0 < cp.length()) {
+            cp.append(File.pathSeparatorChar);
+          }
+          cp.append(url.getPath());
+        }
+      }
+    }
+  }
+
+  /** Takes compiled prolog .class files, puts them into the jar file. */
+  private void createJar(
+      Path archiveFile, List<String> toBeJared, File tempDir, ObjectId metaConfig, ObjectId rulesId)
+      throws IOException {
+    long now = TimeUtil.nowMs();
+    Manifest mf = new Manifest();
+    mf.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");
+    mf.getMainAttributes().putValue("Built-by", "Gerrit Code Review " + Version.getVersion());
+    if (git.getDirectory() != null) {
+      mf.getMainAttributes().putValue("Source-Repository", git.getDirectory().getPath());
+    }
+    mf.getMainAttributes().putValue("Source-Commit", metaConfig.name());
+    mf.getMainAttributes().putValue("Source-Blob", rulesId.name());
+
+    Path tmpjar = Files.createTempFile(archiveFile.getParent(), ".rulec_", ".jar");
+    try (OutputStream stream = Files.newOutputStream(tmpjar);
+        JarOutputStream out = new JarOutputStream(stream, mf)) {
+      byte[] buffer = new byte[10240];
+      // TODO: fixify this loop
+      for (String path : toBeJared) {
+        JarEntry jarAdd = new JarEntry(path);
+        File f = new File(tempDir, path);
+        jarAdd.setTime(now);
+        out.putNextEntry(jarAdd);
+        if (f.isFile()) {
+          try (InputStream in = Files.newInputStream(f.toPath())) {
+            while (true) {
+              int nRead = in.read(buffer, 0, buffer.length);
+              if (nRead <= 0) {
+                break;
+              }
+              out.write(buffer, 0, nRead);
+            }
+          }
+        }
+        out.closeEntry();
+      }
+    }
+
+    try {
+      Files.move(tmpjar, archiveFile);
+    } catch (IOException e) {
+      throw new IOException("Cannot replace " + archiveFile, e);
+    }
+  }
+
+  private List<File> getAllFiles(File dir, String extension) throws IOException {
+    ArrayList<File> fileList = new ArrayList<>();
+    getAllFiles(dir, extension, fileList);
+    return fileList;
+  }
+
+  private void getAllFiles(File dir, String extension, List<File> fileList) throws IOException {
+    for (File f : listFiles(dir)) {
+      if (f.getName().endsWith(extension)) {
+        fileList.add(f);
+      }
+      if (f.isDirectory()) {
+        getAllFiles(f, extension, fileList);
+      }
+    }
+  }
+
+  private List<String> getRelativePaths(File dir, String extension) throws IOException {
+    ArrayList<String> pathList = new ArrayList<>();
+    getRelativePaths(dir, extension, "", pathList);
+    return pathList;
+  }
+
+  private static void getRelativePaths(
+      File dir, String extension, String path, List<String> pathList) throws IOException {
+    for (File f : listFiles(dir)) {
+      if (f.getName().endsWith(extension)) {
+        pathList.add(path + f.getName());
+      }
+      if (f.isDirectory()) {
+        getRelativePaths(f, extension, path + f.getName() + "/", pathList);
+      }
+    }
+  }
+
+  private static void deleteAllFiles(File dir) throws IOException {
+    for (File f : listFiles(dir)) {
+      if (f.isDirectory()) {
+        deleteAllFiles(f);
+      } else {
+        f.delete();
+      }
+    }
+    dir.delete();
+  }
+
+  private static File[] listFiles(File dir) throws IOException {
+    File[] files = dir.listFiles();
+    if (files == null) {
+      throw new IOException("Failed to list directory: " + dir);
+    }
+    return files;
+  }
+}