Parse Account.Ids out of ref names

Change-Id: I8391ff4cf9c99947f9c50e881df7a30c5a1304aa

gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/Account.java

@@ -14,6 +14,8 @@
 
 package com.google.gerrit.reviewdb.client;
 
+import static com.google.gerrit.reviewdb.client.RefNames.REFS_USER;
+
 import com.google.gwtorm.client.Column;
 import com.google.gwtorm.client.IntKey;
 
@@ -105,6 +107,16 @@ public final class Account {
       return r;
     }
 
+    public static Id fromRef(String name) {
+      if (name == null) {
+        return null;
+      }
+      if (name.startsWith(REFS_USER)) {
+        return fromRefPart(name.substring(REFS_USER.length()));
+      }
+      return null;
+    }
+
     /**
      * Parse an Account.Id out of a part of a ref-name.
      *

gerrit-reviewdb/src/test/java/com/google/gerrit/reviewdb/client/AccountTest.java

@@ -20,6 +20,26 @@ import static org.junit.Assert.assertNull;
 import org.junit.Test;
 
 public class AccountTest {
+  @Test
+  public void parseRefName() {
+    assertRef(1, "refs/users/01/1");
+    assertRef(1, "refs/users/01/1-drafts");
+    assertRef(1, "refs/users/01/1-drafts/2");
+
+    assertNotRef(null);
+    assertNotRef("");
+
+    // Invalid characters.
+    assertNotRef("refs/users/01a/1");
+    assertNotRef("refs/users/01/a1");
+
+    // Mismatched shard.
+    assertNotRef("refs/users/01/23");
+
+    // Shard too short.
+    assertNotRef("refs/users/1/1");
+  }
+
   @Test
   public void parseRefNameParts() {
     assertRefPart(1, "01/1");
@@ -43,6 +63,14 @@ public class AccountTest {
     assertNotRefPart("1/1");
   }
 
+  private static void assertRef(int accountId, String refName) {
+    assertEquals(new Account.Id(accountId), Account.Id.fromRef(refName));
+  }
+
+  private static void assertNotRef(String refName) {
+    assertNull(Account.Id.fromRef(refName));
+  }
+
   private static void assertRefPart(int accountId, String refName) {
     assertEquals(new Account.Id(accountId), Account.Id.fromRefPart(refName));
   }