Hide multi-master cache coherency issues on preferences

User preferences are held in memory in the accounts cache, but can be
stale in a multi-master configuration due to writes being handled on a
different server process.  Paper over the lack of cache coherency by
reading the preferences from the database anytime they are requested
through the RPC or REST APIs.

Change-Id: I2a14e1f50e908a1d5ea5628e5a05e392be2e0d42

gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/account/AccountServiceImpl.java

@@ -69,7 +69,12 @@ class AccountServiceImpl extends BaseServiceImplementation implements
   }
 
   public void myAccount(final AsyncCallback<Account> callback) {
-    callback.onSuccess(currentUser.get().getAccount());
+    run(callback, new Action<Account>() {
+      @Override
+      public Account run(ReviewDb db) throws OrmException {
+        return db.accounts().get(currentUser.get().getAccountId());
+      }
+    });
   }
 
   public void changePreferences(final AccountGeneralPreferences pref,

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

@@ -16,28 +16,39 @@ package com.google.gerrit.server.account;
 
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.extensions.restapi.RestReadView;
+import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.AccountDiffPreference;
 import com.google.gerrit.reviewdb.client.AccountDiffPreference.Whitespace;
+import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.CurrentUser;
+import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 
 public class GetDiffPreferences implements RestReadView<AccountResource> {
-
   private final Provider<CurrentUser> self;
+  private final Provider<ReviewDb> db;
 
   @Inject
-  GetDiffPreferences(Provider<CurrentUser> self) {
+  GetDiffPreferences(Provider<CurrentUser> self, Provider<ReviewDb> db) {
     this.self = self;
+    this.db = db;
   }
 
   @Override
-  public DiffPreferencesInfo apply(AccountResource rsrc) throws AuthException {
+  public DiffPreferencesInfo apply(AccountResource rsrc)
+      throws AuthException, OrmException {
     if (self.get() != rsrc.getUser()
         && !self.get().getCapabilities().canAdministrateServer()) {
       throw new AuthException("restricted to administrator");
     }
-    return DiffPreferencesInfo.parse(rsrc.getUser().getAccountDiffPreference());
+
+    Account.Id userId = rsrc.getUser().getAccountId();
+    AccountDiffPreference a = db.get().accountDiffPreferences().get(userId);
+    if (a == null) {
+      a = new AccountDiffPreference(userId);
+    }
+    return DiffPreferencesInfo.parse(a);
   }
 
   static class DiffPreferencesInfo {

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

@@ -15,7 +15,9 @@
 package com.google.gerrit.server.account;
 
 import com.google.gerrit.extensions.restapi.AuthException;
+import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestReadView;
+import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.AccountGeneralPreferences;
 import com.google.gerrit.reviewdb.client.AccountGeneralPreferences.ChangeScreen;
 import com.google.gerrit.reviewdb.client.AccountGeneralPreferences.CommentVisibilityStrategy;
@@ -24,26 +26,34 @@ import com.google.gerrit.reviewdb.client.AccountGeneralPreferences.DiffView;
 import com.google.gerrit.reviewdb.client.AccountGeneralPreferences.DownloadCommand;
 import com.google.gerrit.reviewdb.client.AccountGeneralPreferences.DownloadScheme;
 import com.google.gerrit.reviewdb.client.AccountGeneralPreferences.TimeFormat;
+import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.CurrentUser;
+import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 
 public class GetPreferences implements RestReadView<AccountResource> {
   private final Provider<CurrentUser> self;
+  private final Provider<ReviewDb> db;
 
   @Inject
-  GetPreferences(Provider<CurrentUser> self) {
+  GetPreferences(Provider<CurrentUser> self, Provider<ReviewDb> db) {
     this.self = self;
+    this.db = db;
   }
 
   @Override
-  public PreferenceInfo apply(AccountResource rsrc) throws AuthException {
+  public PreferenceInfo apply(AccountResource rsrc)
+      throws AuthException, ResourceNotFoundException, OrmException {
     if (self.get() != rsrc.getUser()
         && !self.get().getCapabilities().canAdministrateServer()) {
       throw new AuthException("restricted to administrator");
     }
-    return new PreferenceInfo(rsrc.getUser().getAccount()
+    Account a = db.get().accounts().get(rsrc.getUser().getAccountId());
-        .getGeneralPreferences());
+    if (a == null) {
+      throw new ResourceNotFoundException();
+    }
+    return new PreferenceInfo(a.getGeneralPreferences());
   }
 
   static class PreferenceInfo {