Preference provider implementation backed by JSON files in a directory.

chrome/browser/config_dir_policy_provider.cc

+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/config_dir_policy_provider.h"
+
+#include <set>
+
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/scoped_ptr.h"
+#include "base/values.h"
+#include "chrome/common/json_value_serializer.h"
+
+ConfigDirPolicyProvider::ConfigDirPolicyProvider(const FilePath& config_dir)
+    : config_dir_(config_dir) {
+}
+
+bool ConfigDirPolicyProvider::Provide(ConfigurationPolicyStore* store) {
+  scoped_ptr<DictionaryValue> policy(ReadPolicies());
+  DecodePolicyValueTree(policy.get(), store);
+  return true;
+}
+
+DictionaryValue* ConfigDirPolicyProvider::ReadPolicies() {
+  // Enumerate the files and sort them lexicographically.
+  std::set<FilePath> files;
+  file_util::FileEnumerator file_enumerator(config_dir_, false,
+                                            file_util::FileEnumerator::FILES);
+  for (FilePath config_file_path = file_enumerator.Next();
+       !config_file_path.empty(); config_file_path = file_enumerator.Next())
+    files.insert(config_file_path);
+
+  // Start with an empty dictionary and merge the files' contents.
+  DictionaryValue* policy = new DictionaryValue;
+  for (std::set<FilePath>::iterator config_file_iter = files.begin();
+       config_file_iter != files.end(); ++config_file_iter) {
+    JSONFileValueSerializer deserializer(*config_file_iter);
+    int error_code = 0;
+    std::string error_msg;
+    scoped_ptr<Value> value(deserializer.Deserialize(&error_code, &error_msg));
+    if (!value.get()) {
+      LOG(WARNING) << "Failed to read configuration file "
+                   << config_file_iter->value() << ": " << error_msg;
+      continue;
+    }
+    if (!value->IsType(Value::TYPE_DICTIONARY)) {
+      LOG(WARNING) << "Expected JSON dictionary in configuration file "
+                   << config_file_iter->value();
+      continue;
+    }
+    policy->MergeDictionary(static_cast<DictionaryValue*>(value.get()));
+  }
+
+  return policy;
+}