QueryAccounts: Support parameter 'start'

The 'start' query parameter can be supplied to skip a number of
accounts from the list.

Change-Id: I31497d0db3ac6049a645fe2d29984797bd6cfcae
Signed-off-by: Edwin Kempin <ekempin@google.com>

Documentation/rest-api-accounts.txt

@@ -49,6 +49,9 @@ returned.
   ]
 ----
 
+The `S` or `start` query parameter can be supplied to skip a number
+of accounts from the list.
+
 [[suggest-account]]
 To get account suggestions set the parameter `suggest` and provide the
 typed substring as query `q`. If a result limit `n` is not specified,

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/api/accounts/Accounts.java

@@ -140,6 +140,7 @@ public interface Accounts {
   abstract class QueryRequest {
     private String query;
     private int limit;
+    private int start;
 
     /**
      * Executes query and returns a list of accounts.
@@ -165,6 +166,15 @@ public interface Accounts {
       return this;
     }
 
+    /**
+     * Set number of accounts to skip.
+     * Optional; no accounts are skipped when not provided.
+     */
+    public QueryRequest withStart(int start) {
+      this.start = start;
+      return this;
+    }
+
     public String getQuery() {
       return query;
     }
@@ -172,6 +182,10 @@ public interface Accounts {
     public int getLimit() {
       return limit;
     }
+
+    public int getStart() {
+      return start;
+    }
   }
 
   /**

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

@@ -63,6 +63,7 @@ public class QueryAccounts implements RestReadView<TopLevelResource> {
   private boolean suggest;
   private int suggestLimit = 10;
   private String query;
+  private Integer start;
 
   @Option(name = "--suggest", metaVar = "SUGGEST", usage = "suggest users")
   public void setSuggest(boolean suggest) {
@@ -87,6 +88,12 @@ public class QueryAccounts implements RestReadView<TopLevelResource> {
     this.query = query;
   }
 
+  @Option(name = "--start", aliases = {"-S"}, metaVar = "CNT",
+      usage = "Number of accounts to skip")
+  public void setStart(int start) {
+    this.start = start;
+  }
+
   @Inject
   QueryAccounts(AccountControl.Factory accountControlFactory,
       AccountLoader.Factory accountLoaderFactory,
@@ -139,6 +146,9 @@ public class QueryAccounts implements RestReadView<TopLevelResource> {
       if (!suggest) {
         throw new MethodNotAllowedException();
       }
+      if (start != null) {
+        throw new MethodNotAllowedException("option start not allowed");
+      }
       matches = queryFromDb();
     }
 
@@ -151,6 +161,10 @@ public class QueryAccounts implements RestReadView<TopLevelResource> {
       throw new MethodNotAllowedException("query disabled");
     }
 
+    if (start != null) {
+      queryProcessor.setStart(start);
+    }
+
     Map<Account.Id, AccountInfo> matches = new LinkedHashMap<>();
     try {
       Predicate<AccountState> queryPred;

gerrit-server/src/main/java/com/google/gerrit/server/api/accounts/AccountsImpl.java

@@ -123,6 +123,7 @@ public class AccountsImpl implements Accounts {
       QueryAccounts myQueryAccounts = queryAccountsProvider.get();
       myQueryAccounts.setQuery(r.getQuery());
       myQueryAccounts.setLimit(r.getLimit());
+      myQueryAccounts.setStart(r.getStart());
       return myQueryAccounts.apply(TopLevelResource.INSTANCE);
     } catch (OrmException e) {
       throw new RestApiException("Cannot retrieve suggested accounts", e);

gerrit-server/src/main/java/com/google/gerrit/server/query/account/AccountQueryProcessor.java

@@ -57,6 +57,6 @@ public class AccountQueryProcessor extends QueryProcessor<AccountState> {
   protected Predicate<AccountState> enforceVisibility(
       Predicate<AccountState> pred) {
     return new AndSource<>(pred,
-        new AccountIsVisibleToPredicate(accountControlFactory.get()));
+        new AccountIsVisibleToPredicate(accountControlFactory.get()), start);
   }
 }

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

@@ -256,6 +256,17 @@ public abstract class AbstractQueryAccountsTest extends GerritServerTests {
     assertQuery(newQuery(domain).withLimit(2), user1, user2);
   }
 
+  @Test
+  public void withStart() throws Exception {
+    String domain = name("test.com");
+    AccountInfo user1 = newAccountWithEmail("user1", "user1@" + domain);
+    AccountInfo user2 = newAccountWithEmail("user2", "user2@" + domain);
+    AccountInfo user3 = newAccountWithEmail("user3", "user3@" + domain);
+
+    assertQuery(domain, user1, user2, user3);
+    assertQuery(newQuery(domain).withStart(1), user2, user3);
+  }
+
   protected AccountInfo newAccount(String username) throws Exception {
     return newAccountWithEmail(username, null);
   }