[couchdb] 01/01: Pluggable persist_fun

[rn...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

rnewson pushed a commit to branch prototype/fdb-layer-ebtree-persist-fun
in repository https://gitbox.apache.org/repos/asf/couchdb.git

commit ee213c9c995c2be9d103e32c0e2f9d01477a446e
Author: Robert Newson <rn...@apache.org>
AuthorDate: Thu Aug 6 20:04:58 2020 +0100

    Pluggable persist_fun
---
 src/ebtree/src/ebtree.erl | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/ebtree/src/ebtree.erl b/src/ebtree/src/ebtree.erl
index c31f503..bacb42e 100644
--- a/src/ebtree/src/ebtree.erl
+++ b/src/ebtree/src/ebtree.erl
@@ -46,7 +46,8 @@
     max,
     collate_fun,
     reduce_fun,
-    encode_fun
+    encode_fun,
+    persist_fun
 }).
 
 -define(META, 0).
@@ -83,12 +84,14 @@ open(Db, Prefix, Order, Options) when is_binary(Prefix), is_integer(Order), Orde
     ReduceFun = proplists:get_value(reduce_fun, Options, fun reduce_noop/2),
     CollateFun = proplists:get_value(collate_fun, Options, fun collate_raw/2),
     EncodeFun = proplists:get_value(encode_fun, Options, fun encode_erlang/3),
+    PersistFun = proplists:get_value(persist_fun, Options, fun simple_persist/3),
 
     Tree = #tree{
         prefix = Prefix,
         reduce_fun = ReduceFun,
         collate_fun = CollateFun,
-        encode_fun = EncodeFun
+        encode_fun = EncodeFun,
+        persist_fun = PersistFun
     },
 
     erlfdb:transactional(Db, fun(Tx) ->
@@ -772,8 +775,8 @@ meta_key(Prefix, MetaKey) when is_binary(Prefix) ->
 
 get_node(Tx, #tree{} = Tree, Id) ->
     Key = node_key(Tree#tree.prefix, Id),
-    Future = erlfdb:get(Tx, Key),
-    Value = erlfdb:wait(Future),
+    #tree{persist_fun = PersistFun} = Tree,
+    Value = PersistFun(Tx, get, Key),
     decode_node(Tree, Id, Key, Value).
 
 
@@ -785,7 +788,8 @@ clear_nodes(Tx, #tree{} = Tree, Nodes) ->
 
 clear_node(Tx, #tree{} = Tree, #node{} = Node) ->
      Key = node_key(Tree#tree.prefix, Node#node.id),
-     erlfdb:clear(Tx, Key).
+     #tree{persist_fun = PersistFun} = Tree,
+     PersistFun(Tx, clear, Key).
 
 
 set_nodes(Tx, #tree{} = Tree, Nodes) ->
@@ -805,7 +809,8 @@ set_node(Tx, #tree{} = Tree, #node{} = Node) ->
     validate_node(Tree, Node),
     Key = node_key(Tree#tree.prefix, Node#node.id),
     Value = encode_node(Tree, Key, Node),
-    erlfdb:set(Tx, Key, Value).
+    #tree{persist_fun = PersistFun} = Tree,
+    PersistFun(Tx, set, [Key, Value]).
 
 
 node_key(Prefix, Id) when is_binary(Prefix), is_integer(Id) ->
@@ -1006,6 +1011,18 @@ encode_erlang(encode, _Key, Value) ->
 encode_erlang(decode, _Key, Value) ->
     binary_to_term(Value, [safe]).
 
+%% persist function
+
+simple_persist(Tx, set, [Key, Value]) ->
+    erlfdb:set(Tx, Key, Value);
+
+simple_persist(Tx, get, Key) ->
+    erlfdb:wait(erlfdb:get(Tx, Key));
+
+simple_persist(Tx, clear, Key) ->
+    erlfdb:clear(Tx, Key).
+
+
 %% private functions
 
 init_order(#tree{} = Tree, Order)