diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..3d41d01
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,4 @@
+target
+*.iml
+*.ipr
+.idea
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..11069ed
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,201 @@
+                              Apache License
+                        Version 2.0, January 2004
+                     http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+1. Definitions.
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+   "License" shall mean the terms and conditions for use, reproduction,
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diff --git a/README.md b/README.md
new file mode 100644
index 0000000..cb75eb5
--- /dev/null
+++ b/README.md
@@ -0,0 +1,45 @@
+# Gerrit OWNERS Plugin
+
+This plugin provides a Prolog predicate `add_owner_approval/3` that appends `label('Owner-Approval', need(_))` to a provided list.
+
+Owner approval is determined based on OWNERS files located in the same repository. They are resolved against the state present in the existing master branch.
+
+The OWNERS files are represented by the following YAML structure:
+
+```yaml
+inherited: true
+owners:
+- user-a@example.com
+- user-b@example.com
+```
+
+This translates to inheriting owner email address from any parent OWNER files and to allow `user-a@example.com` and `user-b@example.com` to approve the change.
+
+The plugin analyzes the latest patch set by looking at each patch and building an OWNERS hierarchy. It stops once it finds an OWNERS file that has “inherited” set to false (by default it’s true.)
+
+For example, imagine the following tree:
+
+```
+/OWNERS
+/example/src/main/OWNERS
+/example/src/main/java/com/example/foo/Foo.java
+/example/src/main/resources/config.properties
+/example/src/test/OWNERS
+/example/src/test/java/com/example/foo/FooTest.java
+```
+
+If you submit a patch set that changes `/example/src/main/java/com/example/foo/Foo.java` then the plugin will first open `/example/src/main/OWNERS` and if inherited is set to true combine it with the owners listed in `/OWNERS`.
+
+If for each patch there is a reviewer who gave a `Code-Review +2` then the plugin will not add any labels,
+otherwise it will add `label('Owner-Approval', need(_))`.
+
+Here’s a sample rules.pl that uses this predicate to enable the submit rule.
+
+```prolog
+submit_rule(S) :-
+  gerrit:default_submit(D),
+  D =.. [submit | Ds],
+  gerrit:get_commit_labels(L),
+  gerrit_owners:add_owner_approval(L, Ds, A),
+  S =.. [submit | A].
+```
diff --git a/pom.xml b/pom.xml
new file mode 100644
index 0000000..d93c53e
--- /dev/null
+++ b/pom.xml
@@ -0,0 +1,148 @@
+<!--
+Copyright (C) 2012 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.
+-->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>com.vmware</groupId>
+  <artifactId>gerrit-owners</artifactId>
+  <packaging>jar</packaging>
+  <version>1.0-SNAPSHOT</version>
+  <name>gerrit-owners</name>
+
+  <properties>
+    <Gerrit-ApiType>plugin</Gerrit-ApiType>
+    <Gerrit-ApiVersion>2.7-SNAPSHOT</Gerrit-ApiVersion>
+  </properties>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-jar-plugin</artifactId>
+        <version>2.4</version>
+      </plugin>
+
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>2.3.2</version>
+        <configuration>
+          <source>1.6</source>
+          <target>1.6</target>
+          <encoding>UTF-8</encoding>
+        </configuration>
+      </plugin>
+
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-shade-plugin</artifactId>
+        <configuration>
+          <createDependencyReducedPom>false</createDependencyReducedPom>
+          <promoteTransitiveDependencies>true</promoteTransitiveDependencies>
+          <artifactSet>
+            <excludes>
+              <exclude>com.gerritforge:*</exclude>
+              <exclude>com.google.gerrit:*</exclude>
+              <exclude>org.bouncycastle:*</exclude>
+              <exclude>org.slf4j:*</exclude>
+              <exclude>com.google.guava:*</exclude>
+              <exclude>org.eclipse.jgit:*</exclude>
+              <exclude>wsdl4j:wsdl4j:*</exclude>
+            </excludes>
+          </artifactSet>
+          <transformers>
+            <transformer
+                implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+              <manifestEntries>
+                <Implementation-Vendor>VMware, Inc.</Implementation-Vendor>
+                <Implementation-URL>http://github.com/vadims/gerrit-owners</Implementation-URL>
+                <Implementation-Title>${Gerrit-ApiType} ${project.artifactId}</Implementation-Title>
+                <Implementation-Version>${project.version}</Implementation-Version>
+                <Gerrit-ApiType>${Gerrit-ApiType}</Gerrit-ApiType>
+                <Gerrit-ApiVersion>${project.version}</Gerrit-ApiVersion>
+              </manifestEntries>
+            </transformer>
+          </transformers>
+        </configuration>
+        <executions>
+          <execution>
+            <phase>package</phase>
+            <goals>
+              <goal>shade</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+
+    </plugins>
+  </build>
+
+  <dependencies>
+    <dependency>
+      <groupId>com.google.gerrit</groupId>
+      <artifactId>gerrit-${Gerrit-ApiType}-api</artifactId>
+      <version>${Gerrit-ApiVersion}</version>
+      <scope>provided</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>com.googlecode.prolog-cafe</groupId>
+      <artifactId>PrologCafe</artifactId>
+      <version>1.3</version>
+      <scope>provided</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.gitective</groupId>
+      <artifactId>gitective-core</artifactId>
+      <version>0.9.9</version>
+    </dependency>
+
+    <dependency>
+      <groupId>com.fasterxml.jackson.core</groupId>
+      <artifactId>jackson-core</artifactId>
+      <version>2.2.0</version>
+    </dependency>
+
+    <dependency>
+      <groupId>com.fasterxml.jackson.core</groupId>
+      <artifactId>jackson-databind</artifactId>
+      <version>2.2.0</version>
+    </dependency>
+
+    <dependency>
+      <groupId>com.fasterxml.jackson.dataformat</groupId>
+      <artifactId>jackson-dataformat-yaml</artifactId>
+      <version>2.1.4</version>
+    </dependency>
+
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.8.1</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <repositories>
+    <repository>
+      <id>gerrit-api-repository</id>
+      <url>https://gerrit-api.commondatastorage.googleapis.com/snapshot/</url>
+    </repository>
+  </repositories>
+</project>
diff --git a/src/main/java/com/vmware/gerrit/owners/OwnerPredicateProvider.java b/src/main/java/com/vmware/gerrit/owners/OwnerPredicateProvider.java
new file mode 100644
index 0000000..1d9b722
--- /dev/null
+++ b/src/main/java/com/vmware/gerrit/owners/OwnerPredicateProvider.java
@@ -0,0 +1,17 @@
+/*
+ * Copyright (c) 2013 VMware, Inc. All Rights Reserved.
+ */
+package com.vmware.gerrit.owners;
+
+
+import com.google.common.collect.ImmutableSet;
+import com.google.gerrit.extensions.annotations.Listen;
+import com.google.gerrit.rules.PredicateProvider;
+
+@Listen
+public class OwnerPredicateProvider implements PredicateProvider {
+  @Override
+  public ImmutableSet<String> getPackages() {
+    return ImmutableSet.of("gerrit_owners");
+  }
+}
diff --git a/src/main/java/com/vmware/gerrit/owners/OwnersConfig.java b/src/main/java/com/vmware/gerrit/owners/OwnersConfig.java
new file mode 100644
index 0000000..29baa7c
--- /dev/null
+++ b/src/main/java/com/vmware/gerrit/owners/OwnersConfig.java
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2013 VMware, Inc. All Rights Reserved.
+ */
+package com.vmware.gerrit.owners;
+
+import java.util.Set;
+
+/**
+ * OWNERS file model.
+ * <p/>
+ * Used for de-serializing the OWNERS files.
+ */
+public class OwnersConfig {
+  /**
+   * Flag for marking that this OWNERS file inherits from the parent OWNERS.
+   */
+  private boolean inherited = true;
+
+  /**
+   * Set of OWNER email addresses.
+   */
+  private Set<String> owners;
+
+  public boolean isInherited() {
+    return inherited;
+  }
+
+  public void setInherited(boolean inherited) {
+    this.inherited = inherited;
+  }
+
+  public Set<String> getOwners() {
+    return owners;
+  }
+
+  public void setOwners(Set<String> owners) {
+    this.owners = owners;
+  }
+}
diff --git a/src/main/java/com/vmware/gerrit/owners/PathOwnersEntry.java b/src/main/java/com/vmware/gerrit/owners/PathOwnersEntry.java
new file mode 100644
index 0000000..236446b
--- /dev/null
+++ b/src/main/java/com/vmware/gerrit/owners/PathOwnersEntry.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2013 VMware, Inc. All Rights Reserved.
+ */
+package com.vmware.gerrit.owners;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Set;
+
+public class PathOwnersEntry {
+  private String ownersPath;
+  private Set<String> owners;
+
+  public PathOwnersEntry() {
+    owners = new HashSet<String>();
+  }
+
+  public String getOwnersPath() {
+    return ownersPath;
+  }
+
+  public void setOwnersPath(String ownersPath) {
+    this.ownersPath = ownersPath;
+  }
+
+  public Set<String> getOwners() {
+    return owners;
+  }
+
+  public void addOwners(Collection<String> owners) {
+    this.owners.addAll(owners);
+  }
+}
diff --git a/src/main/java/com/vmware/gerrit/owners/PathOwnersStoredValue.java b/src/main/java/com/vmware/gerrit/owners/PathOwnersStoredValue.java
new file mode 100644
index 0000000..56e986b
--- /dev/null
+++ b/src/main/java/com/vmware/gerrit/owners/PathOwnersStoredValue.java
@@ -0,0 +1,135 @@
+/*
+ * Copyright (c) 2013 VMware, Inc. All Rights Reserved.
+ */
+package com.vmware.gerrit.owners;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
+import com.google.common.collect.HashMultimap;
+import com.google.common.collect.SetMultimap;
+import com.google.gerrit.reviewdb.client.Patch;
+import com.google.gerrit.rules.StoredValue;
+import com.google.gerrit.rules.StoredValues;
+import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.patch.PatchList;
+import com.google.gerrit.server.patch.PatchListEntry;
+import com.googlecode.prolog_cafe.lang.Prolog;
+import org.eclipse.jgit.lib.Repository;
+import org.gitective.core.BlobUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Path Owners Stored Value.
+ * <p/>
+ * Cached by the Prolog Engine across rule evaluation. Provides a mapping of OWNERS file referenced by the commit to
+ * a set of emails contained in the OWNERS file.
+ */
+public class PathOwnersStoredValue extends StoredValue<SetMultimap<String, String>> {
+  private static final Logger log = LoggerFactory.getLogger(IdentifiedUser.class);
+
+  @Override
+  protected SetMultimap<String, String> createValue(Prolog engine) {
+    PatchList patchList = StoredValues.PATCH_LIST.get(engine);
+    List<PatchListEntry> patches = patchList.getPatches();
+    Set<String> paths = new HashSet<String>();
+    for (PatchListEntry patch : patches) {
+      // Ignore commit message
+      if (!patch.getNewName().equals("/COMMIT_MSG")) {
+        paths.add(patch.getNewName());
+
+        // If a file was moved then we need approvals for old and new path
+        if (patch.getChangeType() == Patch.ChangeType.RENAMED) {
+          paths.add(patch.getOldName());
+        }
+      }
+    }
+
+    Repository repository = StoredValues.REPOSITORY.get(engine);
+    return getOwners(repository, paths);
+  }
+
+  private SetMultimap<String, String> getOwners(Repository repository, Set<String> paths) {
+    SetMultimap<String, String> result = HashMultimap.create();
+    Map<String, PathOwnersEntry> entries = new HashMap<String, PathOwnersEntry>();
+
+    PathOwnersEntry rootEntry = new PathOwnersEntry();
+    OwnersConfig rootConfig = getOwners(repository, "OWNERS");
+    if (rootConfig != null) {
+      rootEntry.setOwnersPath("OWNERS");
+      rootEntry.addOwners(rootConfig.getOwners());
+    }
+
+    for (String path : paths) {
+      String[] parts = path.split("/");
+
+      PathOwnersEntry currentEntry = rootEntry;
+      StringBuilder builder = new StringBuilder();
+
+      // Iterate through the parent paths, not including the file name itself
+      for (int i = 0, partsLength = parts.length - 1; i < partsLength; i++) {
+        String part = parts[i];
+        builder.append(part).append("/");
+        String partial = builder.toString();
+
+        // Skip if we already parsed this path
+        if (!entries.containsKey(partial)) {
+          String ownersPath = partial + "OWNERS";
+          OwnersConfig config = getOwners(repository, ownersPath);
+          if (config != null) {
+            PathOwnersEntry entry = new PathOwnersEntry();
+            entry.setOwnersPath(ownersPath);
+            entry.addOwners(config.getOwners());
+
+            if (config.isInherited()) {
+              entry.addOwners(currentEntry.getOwners());
+            }
+
+            currentEntry = entry;
+          }
+
+          entries.put(partial, currentEntry);
+        } else {
+          currentEntry = entries.get(partial);
+        }
+      }
+
+      // Only add the path to the OWNERS file to reduce the number of entries in the result
+      if (currentEntry.getOwnersPath() != null) {
+        result.putAll(currentEntry.getOwnersPath(), currentEntry.getOwners());
+      }
+    }
+
+    return result;
+  }
+
+  /**
+   * Returns the parsed OwnersConfig file for the given path if it exists.
+   *
+   * @param repository git repo
+   * @param ownersPath path to OWNERS file in the git repo
+   * @return config or null if it doesn't exist
+   */
+  private OwnersConfig getOwners(Repository repository, String ownersPath) {
+    String owners = BlobUtils.getContent(repository, "master", ownersPath);
+
+    if (owners != null) {
+      ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
+      try {
+        return mapper.readValue(owners, OwnersConfig.class);
+      } catch (IOException e) {
+        log.warn("Invalid OWNERS file: {}", ownersPath, e);
+        return null;
+      }
+    }
+
+    return null;
+  }
+}
diff --git a/src/main/java/gerrit_owners/PRED_$init_0.java b/src/main/java/gerrit_owners/PRED_$init_0.java
new file mode 100644
index 0000000..221df95
--- /dev/null
+++ b/src/main/java/gerrit_owners/PRED_$init_0.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2013 VMware, Inc. All Rights Reserved.
+ */
+package gerrit_owners;
+
+import com.googlecode.prolog_cafe.lang.Operation;
+import com.googlecode.prolog_cafe.lang.Predicate;
+import com.googlecode.prolog_cafe.lang.Prolog;
+import com.googlecode.prolog_cafe.lang.PrologException;
+
+/**
+ * Prolog gerrit_owners predicate initialization.
+ */
+public class PRED_$init_0 extends Predicate.P1 {
+
+  public PRED_$init_0(Operation n) {
+    cont = n;
+  }
+
+  @Override
+  public Operation exec(Prolog engine) throws PrologException {
+    engine.setB0();
+    return cont;
+  }
+}
diff --git a/src/main/java/gerrit_owners/PRED_add_owner_approval_3.java b/src/main/java/gerrit_owners/PRED_add_owner_approval_3.java
new file mode 100644
index 0000000..40cc6aa
--- /dev/null
+++ b/src/main/java/gerrit_owners/PRED_add_owner_approval_3.java
@@ -0,0 +1,175 @@
+/*
+ * Copyright (c) 2013 VMware, Inc. All Rights Reserved.
+ */
+package gerrit_owners;
+
+import com.vmware.gerrit.owners.PathOwnersStoredValue;
+
+import com.google.common.collect.SetMultimap;
+import com.google.common.collect.Sets;
+import com.google.gerrit.reviewdb.client.Account;
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.rules.PrologEnvironment;
+import com.google.gerrit.rules.StoredValues;
+import com.google.gerrit.server.IdentifiedUser;
+import com.google.inject.util.Providers;
+import com.googlecode.prolog_cafe.lang.IntegerTerm;
+import com.googlecode.prolog_cafe.lang.ListTerm;
+import com.googlecode.prolog_cafe.lang.Operation;
+import com.googlecode.prolog_cafe.lang.Predicate;
+import com.googlecode.prolog_cafe.lang.Prolog;
+import com.googlecode.prolog_cafe.lang.PrologException;
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.SymbolTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+import com.googlecode.prolog_cafe.lang.VariableTerm;
+
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Predicate for add_owner_approval/3.
+ * <p/>
+ * Adds OWNERS file approval checks.
+ */
+public class PRED_add_owner_approval_3 extends Predicate.P3 {
+
+  private static final SymbolTerm CODE_REVIEW = SymbolTerm.intern("Code-Review");
+
+  private static final SymbolTerm OWNER_APPROVAL = SymbolTerm.intern("Owner-Approval");
+
+  // Cached path owners.
+  private static PathOwnersStoredValue PATH_OWNERS = new PathOwnersStoredValue();
+
+  public PRED_add_owner_approval_3(Term a1, Term a2, Term a3, Operation n) {
+    arg1 = a1;
+    arg2 = a2;
+    arg3 = a3;
+    cont = n;
+  }
+
+  @Override
+  public Operation exec(Prolog engine) throws PrologException {
+    engine.setB0();
+
+    SetMultimap<String, String> pathOwners = PATH_OWNERS.get(engine);
+
+    Term a1 = arg1.dereference();
+    Term a2 = arg2.dereference();
+    Term a3 = arg3.dereference();
+
+    if (!a3.isVariable()) {
+      return engine.fail();
+    }
+
+    Set<String> emails;
+    if (a1.isList()) {
+      emails = getReviewerEmails(engine, (ListTerm) a1);
+    } else {
+      emails = Collections.emptySet();
+    }
+
+    if (!isOwnerApproved(pathOwners, emails)) {
+      a2 = appendLabel(a2, "need", new VariableTerm(engine));
+    }
+
+    ((VariableTerm) a3).bind(a2, engine.trail);
+
+    return cont;
+  }
+
+  /**
+   * Append commit label.
+   *
+   * @param list     commit labels list
+   * @param status   ok, need, maybe, etc.
+   * @param userTerm commit label user
+   * @return resulting list
+   */
+  private ListTerm appendLabel(Term list, String status, Term userTerm) {
+    StructureTerm label = new StructureTerm("label", OWNER_APPROVAL, new StructureTerm(status, userTerm));
+    return new ListTerm(label, list);
+  }
+
+  /**
+   * Returns if the change has been approved by owners.
+   *
+   * @param pathOwners     map of paths to a set of owners for the path
+   * @param reviewerEmails set of reviewer emails who gave a CR +2
+   * @return true iff all the paths were approved
+   */
+  private boolean isOwnerApproved(SetMultimap<String, String> pathOwners, Set<String> reviewerEmails) {
+    for (String path : pathOwners.keySet()) {
+      Set<String> requiredReviewers = pathOwners.get(path);
+      Sets.SetView<String> intersection = Sets.intersection(requiredReviewers, reviewerEmails);
+      if (intersection.isEmpty()) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  /**
+   * Returns a set of all the reviewer emails that gave a CR +2.
+   *
+   * @param engine prolog engine
+   * @param list   commit labels list
+   * @return set of reviewer emails
+   */
+  private static Set<String> getReviewerEmails(Prolog engine, ListTerm list) {
+    StructureTerm codeReviewTerm = new StructureTerm("label", CODE_REVIEW, new IntegerTerm(2));
+    VariableTerm userIdTerm = new VariableTerm();
+    StructureTerm userTerm = new StructureTerm("user", userIdTerm);
+    StructureTerm commitLabelTerm = new StructureTerm("commit_label", codeReviewTerm, userTerm);
+
+    Set<String> result = new HashSet<String>();
+    while (true) {
+      StructureTerm term = (StructureTerm) list.car();
+      if (commitLabelTerm.unify(term, engine.trail)) {
+        int userId = ((IntegerTerm) userIdTerm.dereference()).intValue();
+        IdentifiedUser user = getUser(engine, userId);
+        result.addAll(user.getEmailAddresses());
+        userIdTerm.undo();
+      }
+
+      if (list.cdr().isList()) {
+        list = (ListTerm) list.cdr();
+      } else {
+        return result;
+      }
+    }
+  }
+
+  /**
+   * Get user from cache or ReviewDb by id.
+   *
+   * @param engine prolog engine
+   * @param id     user id
+   * @return user that matches the given id
+   */
+  private static IdentifiedUser getUser(Prolog engine, int id) {
+    Map<Account.Id, IdentifiedUser> cache = StoredValues.USERS.get(engine);
+    Account.Id accountId = new Account.Id(id);
+    IdentifiedUser user = cache.get(accountId);
+    if (user == null) {
+      ReviewDb db = StoredValues.REVIEW_DB.getOrNull(engine);
+      IdentifiedUser.GenericFactory userFactory = userFactory(engine);
+      IdentifiedUser who;
+      if (db != null) {
+        who = userFactory.create(Providers.of(db), accountId);
+      } else {
+        who = userFactory.create(accountId);
+      }
+      cache.put(accountId, who);
+      user = who;
+    }
+    return user;
+  }
+
+  private static IdentifiedUser.GenericFactory userFactory(Prolog engine) {
+    PrologEnvironment env = (PrologEnvironment) engine.control;
+    return env.getInjector().getInstance(IdentifiedUser.GenericFactory.class);
+  }
+}