Service Manager: Miscellaneous catalog cleanup

services/catalog/entry_cache.h

+// Copyright 2017 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.
+
+#ifndef SERVICES_CATALOG_ENTRY_CACHE_H_
+#define SERVICES_CATALOG_ENTRY_CACHE_H_
+
+#include <map>
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+
+namespace catalog {
+
+class Entry;
+
+// Indexed storage for all existing service catalog entries.
+class EntryCache {
+ public:
+  EntryCache();
+  ~EntryCache();
+
+  // All entries in the cache, including non-root entries.
+  const std::map<std::string, const Entry*>& entries() const {
+    return entries_;
+  }
+
+  // Adds a new root entry to the cache. If a root entry already exists
+  // corresponding to the new entry's name, the old root entry is removed first,
+  // along with its children.
+  //
+  // If a non-root entry already exists corresponding to the new entry's name,
+  // the new entry is ignored.
+  //
+  // Returns |true| if the entry was added and |false| otherwise.
+  //
+  // TODO(rockot): Duplicate entries should be treated as an error, but for now
+  // we tolerate them because of some remaining dependency on Package directory
+  // scanning, which in turn has some unpredictable behavior with respect to
+  // Entry registration.
+  bool AddRootEntry(std::unique_ptr<Entry> entry);
+
+  // Queries the cache for an entry corresponding to |name|. Returns null if
+  // such an entry is not found.
+  const Entry* GetEntry(const std::string& name);
+
+ private:
+  // Adds and entry and its children to |entries_|. Returns |true| if the Entry
+  // was successfully added and |false| otherwise.
+  bool AddEntry(const Entry* entry);
+
+  // Removes an entry and its children from |entries_|.
+  void RemoveEntry(const Entry* entry);
+
+  // Map of top-level service entries. This transitively owns all existing
+  // Entry objects.
+  std::map<std::string, std::unique_ptr<Entry>> root_entries_;
+
+  // Map of service name to Entry. Each value points to an Entry owned either
+  // directly or indirectly by |entries_| above. This is essentially a flattened
+  // version of |entries_| with no ownership.
+  std::map<std::string, const Entry*> entries_;
+
+  DISALLOW_COPY_AND_ASSIGN(EntryCache);
+};
+
+}  // namespace catalog
+
+#endif  // SERVICES_CATALOG_ENTRY_CACHE_H_