Support searching changes that touch directories by regular expressions

Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: I8865dbf9b6dd7bd3b83f2227206f00c8690ddefb

Documentation/user-search.txt

@@ -317,6 +317,10 @@ E.g. a change that touches a file in the directory 'a/b/c' matches for 'a/b/c',
 +
 Slash ('/') is used path separator. Leading and trailing slashes are allowed
 but are not mandatory.
++
+If 'DIR' starts with `^` it matches directories and directory segments by
+regular expression. The link:http://www.brics.dk/automaton/[dk.brics.automaton
+library] is used for evaluation of such patterns.
 
 [[footer]]
 footer:'FOOTER'::

java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java

@@ -781,6 +781,10 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
   @Operator
   public Predicate<ChangeData> directory(String directory) throws QueryParseException {
     if (args.getSchema().hasField(ChangeField.DIRECTORY)) {
+      if (directory.startsWith("^")) {
+        return new RegexDirectoryPredicate(directory);
+      }
+
       return new DirectoryPredicate(directory);
     }
     throw new QueryParseException("'directory' operator is not supported by change index version");

java/com/google/gerrit/server/query/change/RegexDirectoryPredicate.java

@@ -0,0 +1,48 @@
+// Copyright (C) 2019 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.query.change;
+
+import com.google.gerrit.server.index.change.ChangeField;
+import com.google.gwtorm.server.OrmException;
+import dk.brics.automaton.RegExp;
+import dk.brics.automaton.RunAutomaton;
+
+public class RegexDirectoryPredicate extends ChangeRegexPredicate {
+  protected final RunAutomaton pattern;
+
+  public RegexDirectoryPredicate(String re) {
+    super(ChangeField.DIRECTORY, re);
+
+    if (re.startsWith("^")) {
+      re = re.substring(1);
+    }
+
+    if (re.endsWith("$") && !re.endsWith("\\$")) {
+      re = re.substring(0, re.length() - 1);
+    }
+
+    this.pattern = new RunAutomaton(new RegExp(re).toAutomaton());
+  }
+
+  @Override
+  public boolean match(ChangeData cd) throws OrmException {
+    return ChangeField.getDirectories(cd).stream().anyMatch(pattern::run);
+  }
+
+  @Override
+  public int getCost() {
+    return 1;
+  }
+}

javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java

@@ -1581,6 +1581,11 @@ public abstract class AbstractQueryChangesTest extends GerritServerTests {
     assertQuery("directory:/b/c", change5);
     assertQuery("directory:/b/c/", change5);
     assertQuery("directory:b/c/", change5);
+
+    // match by regexp
+    assertQuery("directory:^.*va.*", change2);
+    assertQuery("directory:^documentation/.*/slides", change3);
+    assertQuery("directory:^train.*", change3);
   }
 
   @Test