Index: sync/protocol/unique_position.proto |
diff --git a/sync/protocol/unique_position.proto b/sync/protocol/unique_position.proto |
deleted file mode 100644 |
index 4864f27ae0e400596944f06ac0ac2ca12d1d1957..0000000000000000000000000000000000000000 |
--- a/sync/protocol/unique_position.proto |
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-// Copyright (c) 2012 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. |
-// |
-// Protobuf representation of the UniquePosition class. |
- |
-// Update proto_value_conversions{.h,.cc,_unittest.cc} if you change |
-// any fields in this file. |
- |
-syntax = "proto2"; |
- |
-option optimize_for = LITE_RUNTIME; |
-option retain_unknown_fields = true; |
- |
-package sync_pb; |
- |
-// A UniquePosition is a string of bytes. |
-// |
-// Unique positions are unique per-item, since they are guaranteed to end with a |
-// fixed-length suffix that is unique per-item. The position string may not end |
-// with a '\0' byte. |
-// |
-// Prior to the suffix is a series of arbitrary bytes of arbitrary length. |
-// Items under the same parent are positioned relative to each other by a |
-// lexicographic comparison of their UniquePosition values. |
-message UniquePosition { |
- // History: |
- // |
- // Unique positions were first introduced in M28. This change was rolled out |
- // in such a way that it would try to maintain backwards compatibilty with |
- // clients that understood only the old int64-based positions. |
- // |
- // At first, clients supported only the 'value' field. This version never |
- // made it to stable. We later added support for the 'compressed_value' |
- // field, and clients would populate either one or the other. |
- // |
- // In M30, we added the custom_compressed_v1 representation. This |
- // representation was better than the previous implementations in almost every |
- // way. However, we could not use it right away, since older clients would |
- // not understand it. We decided to write both the old-style ('value' or |
- // 'custom_compressed') representation and the 'custom_compressed_v1' |
- // repersentations to every protobuf during the transition period. Protobufs |
- // written during this transition period would be readable by clients who |
- // understand at least one of the two formats. |
- // |
- // In M33, we dropped support for writing the backwards-compatibility fields. |
- // Protobufs written by this version or later are not be intelligible by |
- // clients with version M29 or older. Those clients will end up making use of |
- // the old int64 position fallback mechanism. |
- |
- // The uncompressed string of bytes representing the position. |
- // |
- // Deprecated. See history note above. |
- optional bytes value = 1; |
- |
- // The client may choose to write a compressed position to this field instead |
- // of populating the 'value' above. If it chooses to use compression, the |
- // 'value' field above must be empty. The position value will be compressed |
- // with gzip and stored in the compressed_value field. The position's |
- // uncompressed length must be specified and written to the |
- // uncompressed_length field. |
- // |
- // Deprecated. See history note above. |
- optional bytes compressed_value = 2; |
- optional uint64 uncompressed_length = 3; |
- |
- // This encoding uses compression scheme designed especially for unique |
- // positions. It has the property that X < Y precisely when Compressed(X) < |
- // Compressed(Y), which is very useful when the most common operation is to |
- // compare these positions against each other. Their values may remain |
- // compressed in memory. |
- // |
- // The compression scheme is implemented and documented in |
- // sync/internal_api/base/unique_position.cc. |
- // |
- // As of M30, this is the preferred encoding. Newer clients may continue to |
- // populate the 'value' and 'compressed_value' fields to ensure backwards |
- // compatibility, but they will always try to read from this field first. |
- optional bytes custom_compressed_v1 = 4; |
-} |