From 6789754d94568d804d7863031de9c2c0b3987c32 Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Wed, 17 Nov 2021 21:46:42 -0500
Subject: [PATCH] some more words about this one weird trick
---
src/_zkapauthorizer/_storage_server.py | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/src/_zkapauthorizer/_storage_server.py b/src/_zkapauthorizer/_storage_server.py
index 5352d0a..d0ec81e 100644
--- a/src/_zkapauthorizer/_storage_server.py
+++ b/src/_zkapauthorizer/_storage_server.py
@@ -783,6 +783,20 @@ def get_writev_price(storage_server, pass_value, storage_index, tw_vectors, now)
# written. If they have an unexpired lease then we can apply some
# or all of the remainder of the value of that lease towards this
# operation.
+ #
+ # For example, if there are 5 0.5 MB shares already present then 5
+ # ZKAPs (assuming a ZKAP value of 1 MB-month) have been spent to
+ # store them while only 2.5 MB of storage has been allocated.
+ # This means we could accept another 2.5 MB of data for storage at
+ # no cost to the client while still having been completely paid
+ # for the storage committed.
+ #
+ # This is sort of a weird trick to try to reduce the impact of
+ # ZKAP value lost to the rounding scheme in use. There's a good
+ # chance there are better solutions waiting to be discovered that
+ # would obsolete this logic. Note that whatever the logic here,
+ # it must agree with the client-side logic so that both server and
+ # client come to the same conclusion regarding price.
sharenums=None,
),
)
--
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