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services/url_response_disk_cache/url_response_disk_cache_db.h

+// Copyright 2015 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_URL_RESPONSE_DISK_CACHE_URL_RESPONSE_DISK_CACHE_DB_H_
+#define SERVICES_URL_RESPONSE_DISK_CACHE_URL_RESPONSE_DISK_CACHE_DB_H_
+
+#include "base/files/file_path.h"
+#include "base/memory/linked_ptr.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "services/url_response_disk_cache/url_response_disk_cache_entry.mojom.h"
+
+namespace leveldb {
+class Comparator;
+class DB;
+class Iterator;
+};
+
+namespace mojo {
+
+// Specialized database for the cache content.
+class URLResponseDiskCacheDB
+    : public base::RefCountedThreadSafe<URLResponseDiskCacheDB> {
+ public:
+  class Iterator {
+   public:
+    explicit Iterator(linked_ptr<leveldb::DB> db);
+    ~Iterator();
+
+    bool HasNext();
+    void GetNext(CacheKeyPtr* key, CacheEntryPtr* entry);
+
+   private:
+    linked_ptr<leveldb::DB> db_;
+    scoped_ptr<leveldb::Iterator> it_;
+  };
+
+  // Constructs the database. |db_path| is the path to the leveldb database. If
+  // the path exists, the database will be opened, otherwise it will be created.
+  explicit URLResponseDiskCacheDB(const base::FilePath& db_path);
+
+  // Set and get the version of the database.
+  uint64_t GetVersion();
+  void SetVersion(uint64_t version);
+
+  // Put an entry for the given |request_origin| and |url|. Older entry for the
+  // same |request_origin| and |url| will not be removed, but will be shadowed
+  // by the new one.
+  void PutNew(const std::string& request_origin,
+              const std::string& url,
+              CacheEntryPtr entry);
+
+  // Returns the newest entry for the given |request_origin| and |url|, or null
+  // if none exist.
+  CacheEntryPtr GetNewest(const std::string& request_origin,
+                          const std::string& url);
+
+  // Delete the entry for the given |key|.
+  void Delete(CacheKeyPtr key);
+
+  // Returns an iterator over all the entries in the database. For a given
+  // |request_origin| and |url|, entries will be sorted from newest to oldest.
+  // An iterator will not be invalidated nor any of its values will be modified
+  // by further changes to the database.
+  scoped_ptr<Iterator> GetIterator();
+
+ private:
+  friend class base::RefCountedThreadSafe<URLResponseDiskCacheDB>;
+  ~URLResponseDiskCacheDB();
+
+  scoped_ptr<leveldb::Comparator> comparator_;
+  linked_ptr<leveldb::DB> db_;
+};
+
+}  // namespace
+
+#endif  // SERVICES_URL_RESPONSE_DISK_CACHE_URL_RESPONSE_DISK_CACHE_DB_H_