The Tor Browser / file comparison
comparison: mobile/android/base/sync/repositories/StoreTracker.java
mobile/android/base/sync/repositories/StoreTracker.java
- branch
- TOR_BUG_3246
- changeset 4
- fc2d59ddac77
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| -1:000000000000 | 0:c14b8de04bb9 |
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| 1 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 2 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 4 | |
| 5 package org.mozilla.gecko.sync.repositories; | |
| 6 | |
| 7 import java.util.Iterator; | |
| 8 | |
| 9 /** | |
| 10 * Our hacky version of transactional semantics. The goal is to prevent | |
| 11 * the following situation: | |
| 12 * | |
| 13 * * AAA is not modified locally. | |
| 14 * * A modified AAA is downloaded during the storing phase. Its local | |
| 15 * timestamp is advanced. | |
| 16 * * The direction of syncing changes, and AAA is now uploaded to the server. | |
| 17 * | |
| 18 * The following situation should still be supported: | |
| 19 * | |
| 20 * * AAA is not modified locally. | |
| 21 * * A modified AAA is downloaded and merged with the local AAA. | |
| 22 * * The merged AAA is uploaded to the server. | |
| 23 * | |
| 24 * As should: | |
| 25 * | |
| 26 * * AAA is modified locally. | |
| 27 * * A modified AAA is downloaded, and discarded or merged. | |
| 28 * * The current version of AAA is uploaded to the server. | |
| 29 * | |
| 30 * We achieve this by tracking GUIDs during the storing phase. If we | |
| 31 * apply a record such that the local copy is substantially the same | |
| 32 * as the record we just downloaded, we add it to a list of records | |
| 33 * to avoid uploading. The definition of "substantially the same" | |
| 34 * depends on the particular repository. The only consideration is "do we | |
| 35 * want to upload this record in this sync?". | |
| 36 * | |
| 37 * Note that items are removed from this list when a fetch that | |
| 38 * considers them for upload completes successfully. The entire list | |
| 39 * is discarded when the session is completed. | |
| 40 * | |
| 41 * This interface exposes methods to: | |
| 42 * | |
| 43 * * During a store, recording that a record has been stored, and should | |
| 44 * thus not be returned in subsequent fetches; | |
| 45 * * During a fetch, checking whether a record should be returned. | |
| 46 * | |
| 47 * In the future this might also grow self-persistence. | |
| 48 * | |
| 49 * See also RepositorySession.trackRecord. | |
| 50 * | |
| 51 * @author rnewman | |
| 52 * | |
| 53 */ | |
| 54 public interface StoreTracker { | |
| 55 | |
| 56 /** | |
| 57 * @param guid | |
| 58 * The GUID of the item to track. | |
| 59 * @return | |
| 60 * Whether the GUID was a newly tracked value. | |
| 61 */ | |
| 62 public boolean trackRecordForExclusion(String guid); | |
| 63 | |
| 64 /** | |
| 65 * @param guid | |
| 66 * The GUID of the item to check. | |
| 67 * @return | |
| 68 * true if the item is already tracked. | |
| 69 */ | |
| 70 public boolean isTrackedForExclusion(String guid); | |
| 71 | |
| 72 /** | |
| 73 * | |
| 74 * @param guid | |
| 75 * @return true if the specified GUID was removed from the tracked set. | |
| 76 */ | |
| 77 public boolean untrackStoredForExclusion(String guid); | |
| 78 | |
| 79 public RecordFilter getFilter(); | |
| 80 | |
| 81 public Iterator<String> recordsTrackedForExclusion(); | |
| 82 } |
