1 files changed, 263 insertions, 0 deletions
diff --git a/java/com/google/gerrit/server/rules/PrologEnvironment.java b/java/com/google/gerrit/server/rules/PrologEnvironment.java
new file mode 100644
index 0000000000..568fa4eefc
--- /dev/null
+++ b/java/com/google/gerrit/server/rules/PrologEnvironment.java
@@ -0,0 +1,263 @@
+// 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.server.rules;
+
+import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.server.AnonymousUser;
+import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.PatchSetUtil;
+import com.google.gerrit.server.account.Emails;
+import com.google.gerrit.server.config.GerritServerConfig;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.patch.PatchListCache;
+import com.google.gerrit.server.patch.PatchSetInfoFactory;
+import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.project.ProjectCache;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.Singleton;
+import com.google.inject.assistedinject.Assisted;
+import com.googlecode.prolog_cafe.lang.BufferingPrologControl;
+import com.googlecode.prolog_cafe.lang.Predicate;
+import com.googlecode.prolog_cafe.lang.PredicateEncoder;
+import com.googlecode.prolog_cafe.lang.Prolog;
+import com.googlecode.prolog_cafe.lang.PrologMachineCopy;
+import java.util.EnumSet;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import org.eclipse.jgit.lib.Config;
+
+/**
+ * Per-thread Prolog interpreter.
+ *
+ * <p>This class is not thread safe.
+ *
+ * <p>A single copy of the Prolog interpreter, for the current thread.
+ */
+public class PrologEnvironment extends BufferingPrologControl {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  public interface Factory {
+    /**
+     * Construct a new Prolog interpreter.
+     *
+     * @param src the machine to template the new environment from.
+     * @return the new interpreter.
+     */
+    PrologEnvironment create(PrologMachineCopy src);
+  }
+
+  private final Args args;
+  private final Map<StoredValue<Object>, Object> storedValues;
+  private List<Runnable> cleanup;
+
+  @Inject
+  PrologEnvironment(Args a, @Assisted PrologMachineCopy src) {
+    super(src);
+    setEnabled(EnumSet.allOf(Prolog.Feature.class), false);
+    args = a;
+    storedValues = new HashMap<>();
+    cleanup = new LinkedList<>();
+  }
+
+  public Args getArgs() {
+    return args;
+  }
+
+  @Override
+  public void setPredicate(Predicate goal) {
+    super.setPredicate(goal);
+    int reductionLimit = args.reductionLimit(goal);
+    logger.atFine().log("setting reductionLimit %d", reductionLimit);
+    setReductionLimit(reductionLimit);
+  }
+
+  /**
+   * Lookup a stored value in the interpreter's hash manager.
+   *
+   * @param <T> type of stored Java object.
+   * @param sv unique key.
+   * @return the value; null if not stored.
+   */
+  @SuppressWarnings("unchecked")
+  public <T> T get(StoredValue<T> sv) {
+    return (T) storedValues.get(sv);
+  }
+
+  /**
+   * Set a stored value on the interpreter's hash manager.
+   *
+   * @param <T> type of stored Java object.
+   * @param sv unique key.
+   * @param obj the value to store under {@code sv}.
+   */
+  @SuppressWarnings("unchecked")
+  public <T> void set(StoredValue<T> sv, T obj) {
+    storedValues.put((StoredValue<Object>) sv, obj);
+  }
+
+  /**
+   * Copy the stored values from another interpreter to this one. Also gets the cleanup from the
+   * child interpreter
+   */
+  public void copyStoredValues(PrologEnvironment child) {
+    storedValues.putAll(child.storedValues);
+    setCleanup(child.cleanup);
+  }
+
+  /**
+   * Assign the environment a cleanup list (in order to use a centralized list) If this
+   * enivronment's list is non-empty, append its cleanup tasks to the assigning list.
+   */
+  public void setCleanup(List<Runnable> newCleanupList) {
+    newCleanupList.addAll(cleanup);
+    cleanup = newCleanupList;
+  }
+
+  /**
+   * Adds cleanup task to run when close() is called
+   *
+   * @param task is run when close() is called
+   */
+  public void addToCleanup(Runnable task) {
+    cleanup.add(task);
+  }
+
+  /** Release resources stored in interpreter's hash manager. */
+  public void close() {
+    for (Iterator<Runnable> i = cleanup.iterator(); i.hasNext(); ) {
+      try {
+        i.next().run();
+      } catch (Throwable err) {
+        logger.atSevere().withCause(err).log("Failed to execute cleanup for PrologEnvironment");
+      }
+      i.remove();
+    }
+  }
+
+  @Singleton
+  public static class Args {
+    private static final Class<Predicate> CONSULT_STREAM_2;
+
+    static {
+      try {
+        @SuppressWarnings("unchecked")
+        Class<Predicate> c =
+            (Class<Predicate>)
+                Class.forName(
+                    PredicateEncoder.encode(Prolog.BUILTIN, "consult_stream", 2),
+                    false,
+                    RulesCache.class.getClassLoader());
+        CONSULT_STREAM_2 = c;
+      } catch (ClassNotFoundException e) {
+        throw new LinkageError("cannot find predicate consult_stream", e);
+      }
+    }
+
+    private final ProjectCache projectCache;
+    private final PermissionBackend permissionBackend;
+    private final GitRepositoryManager repositoryManager;
+    private final PatchListCache patchListCache;
+    private final PatchSetInfoFactory patchSetInfoFactory;
+    private final IdentifiedUser.GenericFactory userFactory;
+    private final Provider<AnonymousUser> anonymousUser;
+    private final int reductionLimit;
+    private final int compileLimit;
+    private final PatchSetUtil patchsetUtil;
+    private Emails emails;
+
+    @Inject
+    Args(
+        ProjectCache projectCache,
+        PermissionBackend permissionBackend,
+        GitRepositoryManager repositoryManager,
+        PatchListCache patchListCache,
+        PatchSetInfoFactory patchSetInfoFactory,
+        IdentifiedUser.GenericFactory userFactory,
+        Provider<AnonymousUser> anonymousUser,
+        @GerritServerConfig Config config,
+        PatchSetUtil patchsetUtil,
+        Emails emails) {
+      this.projectCache = projectCache;
+      this.permissionBackend = permissionBackend;
+      this.repositoryManager = repositoryManager;
+      this.patchListCache = patchListCache;
+      this.patchSetInfoFactory = patchSetInfoFactory;
+      this.userFactory = userFactory;
+      this.anonymousUser = anonymousUser;
+      this.patchsetUtil = patchsetUtil;
+      this.emails = emails;
+
+      int limit = config.getInt("rules", null, "reductionLimit", 100000);
+      reductionLimit = limit <= 0 ? Integer.MAX_VALUE : limit;
+
+      limit =
+          config.getInt(
+              "rules",
+              null,
+              "compileReductionLimit",
+              (int) Math.min(10L * limit, Integer.MAX_VALUE));
+      compileLimit = limit <= 0 ? Integer.MAX_VALUE : limit;
+
+      logger.atInfo().log("reductionLimit: %d, compileLimit: %d", reductionLimit, compileLimit);
+    }
+
+    private int reductionLimit(Predicate goal) {
+      if (goal.getClass() == CONSULT_STREAM_2) {
+        return compileLimit;
+      }
+      return reductionLimit;
+    }
+
+    public ProjectCache getProjectCache() {
+      return projectCache;
+    }
+
+    public PermissionBackend getPermissionBackend() {
+      return permissionBackend;
+    }
+
+    public GitRepositoryManager getGitRepositoryManager() {
+      return repositoryManager;
+    }
+
+    public PatchListCache getPatchListCache() {
+      return patchListCache;
+    }
+
+    public PatchSetInfoFactory getPatchSetInfoFactory() {
+      return patchSetInfoFactory;
+    }
+
+    public IdentifiedUser.GenericFactory getUserFactory() {
+      return userFactory;
+    }
+
+    public AnonymousUser getAnonymousUser() {
+      return anonymousUser.get();
+    }
+
+    public PatchSetUtil getPatchsetUtil() {
+      return patchsetUtil;
+    }
+
+    public Emails getEmails() {
+      return emails;
+    }
+  }
+}