1 files changed, 120 insertions, 0 deletions
diff --git a/java/com/google/gerrit/server/config/GerritServerConfigProvider.java b/java/com/google/gerrit/server/config/GerritServerConfigProvider.java
new file mode 100644
index 0000000000..8df21da1b3
--- /dev/null
+++ b/java/com/google/gerrit/server/config/GerritServerConfigProvider.java
@@ -0,0 +1,120 @@
+// Copyright (C) 2009 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.config;
+
+import static java.util.stream.Collectors.joining;
+
+import com.google.common.flogger.FluentLogger;
+import com.google.gerrit.common.Nullable;
+import com.google.gerrit.server.notedb.NotesMigration;
+import com.google.gerrit.server.securestore.SecureStore;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.ProvisionException;
+import com.google.inject.Singleton;
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import org.eclipse.jgit.errors.ConfigInvalidException;
+import org.eclipse.jgit.lib.Config;
+import org.eclipse.jgit.storage.file.FileBasedConfig;
+import org.eclipse.jgit.util.FS;
+
+/**
+ * Provides {@link Config} annotated with {@link GerritServerConfig}.
+ *
+ * <p>To react on config updates, the caller should implement @see GerritConfigListener.
+ *
+ * <p>The few callers that need a reloaded-on-demand config can inject a {@code
+ * GerritServerConfigProvider} and request the lastest config with fetchLatestConfig().
+ */
+@Singleton
+public class GerritServerConfigProvider implements Provider<Config> {
+  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
+  private final SitePaths site;
+  private final SecureStore secureStore;
+
+  private final Object lock = new Object();
+
+  private GerritConfig gerritConfig;
+
+  @Inject
+  GerritServerConfigProvider(SitePaths site, SecureStore secureStore) {
+    this.site = site;
+    this.secureStore = secureStore;
+    this.gerritConfig = loadConfig();
+  }
+
+  @Override
+  public Config get() {
+    synchronized (lock) {
+      return gerritConfig;
+    }
+  }
+
+  protected ConfigUpdatedEvent updateConfig() {
+    synchronized (lock) {
+      Config oldConfig = gerritConfig;
+      gerritConfig = loadConfig();
+      return new ConfigUpdatedEvent(oldConfig, gerritConfig);
+    }
+  }
+
+  public GerritConfig loadConfig() {
+    FileBasedConfig baseConfig = loadConfig(null, site.gerrit_config);
+    if (!baseConfig.getFile().exists()) {
+      logger.atInfo().log("No %s; assuming defaults", site.gerrit_config.toAbsolutePath());
+    }
+
+    FileBasedConfig noteDbConfigOverBaseConfig = loadConfig(baseConfig, site.notedb_config);
+    checkNoteDbConfig(noteDbConfigOverBaseConfig);
+
+    return new GerritConfig(noteDbConfigOverBaseConfig, baseConfig, secureStore);
+  }
+
+  private static FileBasedConfig loadConfig(@Nullable Config base, Path path) {
+    FileBasedConfig cfg = new FileBasedConfig(base, path.toFile(), FS.DETECTED);
+    try {
+      cfg.load();
+    } catch (IOException | ConfigInvalidException e) {
+      throw new ProvisionException(e.getMessage(), e);
+    }
+    return cfg;
+  }
+
+  private static void checkNoteDbConfig(FileBasedConfig noteDbConfig) {
+    List<String> bad = new ArrayList<>();
+    for (String section : noteDbConfig.getSections()) {
+      if (section.equals(NotesMigration.SECTION_NOTE_DB)) {
+        continue;
+      }
+      for (String subsection : noteDbConfig.getSubsections(section)) {
+        noteDbConfig
+            .getNames(section, subsection, false)
+            .forEach(n -> bad.add(section + "." + subsection + "." + n));
+      }
+      noteDbConfig.getNames(section, false).forEach(n -> bad.add(section + "." + n));
+    }
+    if (!bad.isEmpty()) {
+      throw new ProvisionException(
+          "Non-NoteDb config options not allowed in "
+              + noteDbConfig.getFile()
+              + ":\n"
+              + bad.stream().collect(joining("\n")));
+    }
+  }
+}