Set '_more_accounts' on last account of query result

If the number of accounts matching the query exceeds the limit the
last account has a '_more_accounts: true' JSON field set.

Change-Id: Icc8c34c37c72f7df00bb06c67602bea36a4ae09f
Signed-off-by: Edwin Kempin <ekempin@google.com>

Documentation/rest-api-accounts.txt

@@ -23,7 +23,7 @@ returned.
 
 .Request
 ----
-  GET /accounts/?q=name:John+email:example.com HTTP/1.0
+  GET /accounts/?q=name:John+email:example.com&n=2 HTTP/1.0
 ----
 
 .Response
@@ -44,11 +44,16 @@ returned.
       "_account_id": 1001439,
       "name": "John Smith",
       "email": "john.smith@example.com",
-      "username": "jsmith"
+      "username": "jsmith",
+      "_more_accounts": true
     }
   ]
 ----
 
+If the number of accounts matching the query exceeds either the
+internal limit or a supplied `n` query parameter, the last account
+object has a `_more_accounts: true` JSON field set.
+
 The `S` or `start` query parameter can be supplied to skip a number
 of accounts from the list.
 
@@ -1938,20 +1943,23 @@ registered.
 The `AccountInfo` entity contains information about an account.
 
 [options="header",cols="1,^1,5"]
-|===========================
-|Field Name    ||Description
-|`_account_id` ||The numeric ID of the account.
-|`name`        |optional|The full name of the user. +
+|=============================
+|Field Name      ||Description
+|`_account_id`   ||The numeric ID of the account.
+|`name`          |optional|The full name of the user. +
 Only set if link:rest-api-changes.html#detailed-accounts[detailed
 account information] is requested.
-|`email`       |optional|
+|`email`         |optional|
 The email address the user prefers to be contacted through. +
 Only set if link:rest-api-changes.html#detailed-accounts[detailed
 account information] is requested.
-|`username`    |optional|The username of the user. +
+|`username`      |optional|The username of the user. +
 Only set if link:rest-api-changes.html#detailed-accounts[detailed
 account information] is requested.
-|===========================
+|`_more_accounts`|optional, not set if `false`|
+Whether the query would deliver more results if not limited. +
+Only set on the last account that is returned.
+|=============================
 
 [[account-input]]
 === AccountInput

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/common/AccountInfo.java

@@ -22,6 +22,7 @@ public class AccountInfo {
   public String email;
   public String username;
   public List<AvatarInfo> avatars;
+  public Boolean _moreAccounts;
 
   public AccountInfo(Integer id) {
     this._accountId = id;

gerrit-server/src/main/java/com/google/gerrit/server/account/QueryAccounts.java

@@ -15,7 +15,7 @@
 package com.google.gerrit.server.account;
 
 import com.google.common.base.Strings;
-import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.ImmutableList;
 import com.google.gerrit.extensions.common.AccountInfo;
 import com.google.gerrit.extensions.restapi.BadRequestException;
 import com.google.gerrit.extensions.restapi.MethodNotAllowedException;
@@ -39,7 +39,6 @@ import com.google.inject.Inject;
 import org.eclipse.jgit.lib.Config;
 import org.kohsuke.args4j.Option;
 
-import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.LinkedHashMap;
@@ -139,23 +138,20 @@ public class QueryAccounts implements RestReadView<TopLevelResource> {
     }
 
     AccountIndex searchIndex = indexes.getSearchIndex();
-    Collection<AccountInfo> matches;
     if (searchIndex != null) {
-      matches = queryFromIndex();
-    } else {
-      if (!suggest) {
-        throw new MethodNotAllowedException();
-      }
-      if (start != null) {
-        throw new MethodNotAllowedException("option start not allowed");
-      }
-      matches = queryFromDb();
+      return queryFromIndex();
     }
 
-    return AccountInfoComparator.ORDER_NULLS_LAST.sortedCopy(matches);
+    if (!suggest) {
+      throw new MethodNotAllowedException();
+    }
+    if (start != null) {
+      throw new MethodNotAllowedException("option start not allowed");
+    }
+    return queryFromDb();
   }
 
-  public Collection<AccountInfo> queryFromIndex()
+  public List<AccountInfo> queryFromIndex()
       throws BadRequestException, MethodNotAllowedException, OrmException {
     if (queryProcessor.isDisabled()) {
       throw new MethodNotAllowedException("query disabled");
@@ -179,18 +175,24 @@ public class QueryAccounts implements RestReadView<TopLevelResource> {
         Account.Id id = accountState.getAccount().getId();
         matches.put(id, accountLoader.get(id));
       }
+
+      accountLoader.fill();
+
+      List<AccountInfo> sorted =
+          AccountInfoComparator.ORDER_NULLS_LAST.sortedCopy(matches.values());
+      if (!sorted.isEmpty() && result.more()) {
+        sorted.get(sorted.size() - 1)._moreAccounts = true;
+      }
+      return sorted;
     } catch (QueryParseException e) {
       if (suggest) {
-        return ImmutableSet.of();
+        return ImmutableList.of();
       }
       throw new BadRequestException(e.getMessage());
     }
-
-    accountLoader.fill();
-    return matches.values();
   }
 
-  public Collection<AccountInfo> queryFromDb() throws OrmException {
+  public List<AccountInfo> queryFromDb() throws OrmException {
     String a = query;
     String b = a + MAX_SUFFIX;
 
@@ -223,7 +225,7 @@ public class QueryAccounts implements RestReadView<TopLevelResource> {
       }
     }
 
-    return matches.values();
+    return AccountInfoComparator.ORDER_NULLS_LAST.sortedCopy(matches.values());
   }
 
   private boolean addSuggestion(Map<Account.Id, AccountInfo> map, Account a) {

gerrit-server/src/test/java/com/google/gerrit/server/query/account/AbstractQueryAccountsTest.java

@@ -252,8 +252,11 @@ public abstract class AbstractQueryAccountsTest extends GerritServerTests {
     AccountInfo user2 = newAccountWithEmail("user2", "user2@" + domain);
     AccountInfo user3 = newAccountWithEmail("user3", "user3@" + domain);
 
-    assertQuery(domain, user1, user2, user3);
-    assertQuery(newQuery(domain).withLimit(2), user1, user2);
+    List<AccountInfo> result = assertQuery(domain, user1, user2, user3);
+    assertThat(result.get(result.size() - 1)._moreAccounts).isNull();
+
+    result = assertQuery(newQuery(domain).withLimit(2), user1, user2);
+    assertThat(result.get(result.size() - 1)._moreAccounts).isTrue();
   }
 
   @Test