tonysun83 commented on a change in pull request #740: Add Bookmark support for mango json queries URL: https://github.com/apache/couchdb/pull/740#discussion_r132597476
########## File path: src/mango/src/mango_json_bookmark.erl ########## @@ -0,0 +1,68 @@ +% Licensed under the Apache License, Version 2.0 (the "License"); you may not +% use this file except in compliance with the License. You may obtain a copy of +% the License at +% +% http://www.apache.org/licenses/LICENSE-2.0 +% +% Unless required by applicable law or agreed to in writing, software +% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +% License for the specific language governing permissions and limitations under +% the License. + + +-module(mango_json_bookmark). + +-export([ + update_args/2, + create/1 +]). + + +-include_lib("couch_mrview/include/couch_mrview.hrl"). +-include("mango_cursor.hrl"). +-include("mango.hrl"). + +update_args(EncodedBookmark, Args) -> + Bookmark = unpack(EncodedBookmark), + update_args2(Bookmark, Args). + + +update_args2(Bookmark, #mrargs{skip = Skip} = Args) when is_list(Bookmark) -> + case lists:keymember(startkey, 1, Bookmark) andalso lists:keymember(startkey_docid, 1, Bookmark) of + true -> + {startkey, Startkey} = lists:keyfind(startkey, 1, Bookmark), + {startkey_docid, StartkeyDocId} = lists:keyfind(startkey_docid, 1, Bookmark), + Args2 = Args#mrargs{ + start_key = Startkey, + start_key_docid = StartkeyDocId, + skip = 1 + Skip + }, + Args2; + false -> + Args + end; +update_args2(_Bookmark, Args) -> + Args. + + +create(#cursor{bookmark_docid = BookmarkDocId, bookmark_key = BookmarkKey}) when BookmarkKey =/= undefined -> + QueryArgs = [ + {startkey_docid, BookmarkDocId}, + {startkey, BookmarkKey} + ], + Bin = term_to_binary(QueryArgs, [compressed, {minor_version,1}]), + couch_util:encodeBase64Url(Bin); +create(#cursor{bookmark = Bookmark}) -> + Bookmark. + + +unpack(nil) -> + nil; +unpack(Packed) -> + try + binary_to_term(couch_util:decodeBase64Url(Packed)) Review comment: This part got me thinking a bit. What is a valid vs invalid bookmark? So when unpacked, a json bookmark is a start_key and end_key range, and a text bookmark is a node+shard range. So the composition is slightly different. So a text index bookmark should be considered invalid for a json index bookmark right? When I tried that particular scenario, the bookmark passed correctly ``` Here's a sample text bookmark: "g2wAAAACaAJkAA5zdGFydGtleV9kb2NpZG0AAAAkZTkwMDAwMWQtYmM0OC00OGE2LTliMWEtYWM5YTFmNWQxYTAzaAJkAAhzdGFydGtleWsAAStq"``` . If you did it the other way around...substitute a json index bookmark into a text index bookmark, it fails with invalid_bookmark. Wondering if we should be more consistent/strict and and verify both types of bookmarks? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
