Add base persistence interfaces for Prefetching Offline Pages.

components/offline_pages/core/prefetch/prefetch_item.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 COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_ITEM_H_
+#define COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_ITEM_H_
+
+#include <string>
+
+#include "base/time/time.h"
+#include "components/offline_pages/core/prefetch/prefetch_types.h"
+#include "url/gurl.h"
+
+namespace offline_pages {
+
+// Data object representing an item progressing through the prefetching process
+// from the moment a URL is requested by a client until its processing is done,
+// successfully or not.
+// Instances of this class are in-memory representations of items in (or to be
+// inserted into) the persistent prefetching data store.
+struct PrefetchItem {
+  PrefetchItem();
+  explicit PrefetchItem(const PrefetchItem& other);
+
+  ~PrefetchItem();
+
+  bool operator==(const PrefetchItem& other) const;
+  bool operator!=(const PrefetchItem& other) const;
+
+  // Primary key/ID for this prefetch item (See |base::GenerateGUID()|). This
+  // value will be reused when communicating with other systems accepting GUID
+  // identifiers for operations linked to this item.
+  std::string guid;
+
+  // Externally provided namespace and id values so that this item can be
+  // uniquely identified by the client requesting it. It is the client's
+  // responsibility to make sure the id is unique within the context of its
+  // assigned namespace.
+  std::string client_name_space;
+  std::string client_id;
+
+  // Current prefetching progress state.
+  PrefetchItemState state = PrefetchItemState::NEW_REQUEST;
+
+  // The URL of the page the client requested to be prefetched.
+  GURL url;
+
+  // The final URL whose page was actually included in a successfully created
+  // archive after redirects, if it was different than the |url|. It will be
+  // left empty if they are the same.
+  GURL final_archived_url;
+
+  // Number of times an attempt was made to generate an archive for this item.
+  int request_archive_attempt_count = 0;
+
+  // Name used to identify the archiving operation being executed by the
+  // prefetching service for processing this item's URL. It is used as the
+  // |operation_name| reported by an incoming GCM message and in the
+  // |GetOperationRequest.name| field of the respective GetOperation RPC.
+  std::string operation_name;
+
+  // The name specific to this item's archive that can be used to build the URL
+  // to allow the downloading of that archive. Will only be set when and if an
+  // archive was successfully created for this item. It will be kept empty
+  // otherwise.
+  std::string archive_body_name;
+
+  // The final size of the generated archive that contains this item's page
+  // snapshot. The archive might also include other articles in a bundle so the
+  // length is not necessarily directly related to this item's page contents.
+  // Will only be set when and if an archive was successfully created for this
+  // item. It holds a negative value otherwise.
+  int64_t archive_body_length = -1;
+
+  // Time when this item was inserted into the store with the URL to be
+  // prefetched.
+  base::Time creation_time;
+
+  // Time used for the expiration of the item depending on the applicable policy
+  // for its current state. It is initially set with the same value as
+  // |creation_time|. Its value is "refreshed" to the current time on some state
+  // transitions considered significant for the prefetching process.
+  base::Time freshness_time;
+
+  // The reason why the item was set to the FINISHED state. Should be
+  // disregarded until reaching that state.
+  PrefetchItemErrorCode error_code = PrefetchItemErrorCode::SUCCESS;
+};
+
+}  // namespace offline_pages
+
+#endif  // COMPONENTS_OFFLINE_PAGES_CORE_PREFETCH_PREFETCH_ITEM_H_