From 1c4510cc053005dd20ed3e63c8542847bb0155f9 Mon Sep 17 00:00:00 2001 From: Riley Bruins Date: Sun, 1 Sep 2024 16:54:30 -0700 Subject: [PATCH] feat(func): allow manual cache invalidation for _memoize This commit also adds some tests for the existing memoization functionality. --- runtime/lua/vim/func.lua | 14 +-- runtime/lua/vim/func/_memoize.lua | 56 +++++++--- runtime/lua/vim/treesitter/query.lua | 4 +- test/functional/func/memoize_spec.lua | 142 ++++++++++++++++++++++++++ 4 files changed, 191 insertions(+), 25 deletions(-) create mode 100644 test/functional/func/memoize_spec.lua diff --git a/runtime/lua/vim/func.lua b/runtime/lua/vim/func.lua index f71659ffb4..fc8fa62c71 100644 --- a/runtime/lua/vim/func.lua +++ b/runtime/lua/vim/func.lua @@ -3,9 +3,6 @@ local M = {} -- TODO(lewis6991): Private for now until: -- - There are other places in the codebase that could benefit from this -- (e.g. LSP), but might require other changes to accommodate. --- - Invalidation of the cache needs to be controllable. Using weak tables --- is an acceptable invalidation policy, but it shouldn't be the only --- one. -- - I don't think the story around `hash` is completely thought out. We -- may be able to have a good default hash by hashing each argument, -- so basically a better 'concat'. @@ -17,6 +14,10 @@ local M = {} --- Internally uses a |lua-weaktable| to cache the results of {fn} meaning the --- cache will be invalidated whenever Lua does garbage collection. --- +--- The cache can also be manually invalidated by calling `:clear()` on the returned object. +--- Calling this function with no arguments clears the entire cache; otherwise, the arguments will +--- be interpreted as function inputs, and only the cache entry at their hash will be cleared. +--- --- The memoized function returns shared references so be wary about --- mutating return values. --- @@ -32,11 +33,12 @@ local M = {} --- first n arguments passed to {fn}. --- --- @param fn F Function to memoize. ---- @param strong? boolean Do not use a weak table +--- @param weak? boolean Use a weak table (default `true`) --- @return F # Memoized version of {fn} --- @nodoc -function M._memoize(hash, fn, strong) - return require('vim.func._memoize')(hash, fn, strong) +function M._memoize(hash, fn, weak) + -- this is wrapped in a function to lazily require the module + return require('vim.func._memoize')(hash, fn, weak) end return M diff --git a/runtime/lua/vim/func/_memoize.lua b/runtime/lua/vim/func/_memoize.lua index 65210351bf..f5ae6e16ac 100644 --- a/runtime/lua/vim/func/_memoize.lua +++ b/runtime/lua/vim/func/_memoize.lua @@ -1,5 +1,7 @@ --- Module for private utility functions +--- @alias vim.func.MemoObj { _hash: (fun(...): any), _weak: boolean?, _cache: table } + --- @param argc integer? --- @return fun(...): any local function concat_hash(argc) @@ -33,31 +35,51 @@ local function resolve_hash(hash) return hash end +--- @param weak boolean? +--- @return table +local create_cache = function(weak) + return setmetatable({}, { + __mode = weak ~= false and 'kv', + }) +end + --- @generic F: function --- @param hash integer|string|fun(...): any --- @param fn F ---- @param strong? boolean +--- @param weak? boolean --- @return F -return function(hash, fn, strong) +return function(hash, fn, weak) vim.validate({ hash = { hash, { 'number', 'string', 'function' } }, fn = { fn, 'function' }, + weak = { weak, 'boolean', true }, }) - ---@type table> - local cache = {} - if not strong then - setmetatable(cache, { __mode = 'kv' }) - end + --- @type vim.func.MemoObj + local obj = { + _cache = create_cache(weak), + _hash = resolve_hash(hash), + _weak = weak, + --- @param self vim.func.MemoObj + clear = function(self, ...) + if select('#', ...) == 0 then + self._cache = create_cache(self._weak) + return + end + local key = self._hash(...) + self._cache[key] = nil + end, + } - hash = resolve_hash(hash) - - return function(...) - local key = hash(...) - if cache[key] == nil then - cache[key] = vim.F.pack_len(fn(...)) - end - - return vim.F.unpack_len(cache[key]) - end + return setmetatable(obj, { + --- @param self vim.func.MemoObj + __call = function(self, ...) + local key = self._hash(...) + local cache = self._cache + if cache[key] == nil then + cache[key] = vim.F.pack_len(fn(...)) + end + return vim.F.unpack_len(cache[key]) + end, + }) end diff --git a/runtime/lua/vim/treesitter/query.lua b/runtime/lua/vim/treesitter/query.lua index bd0574b8b7..53c7c90330 100644 --- a/runtime/lua/vim/treesitter/query.lua +++ b/runtime/lua/vim/treesitter/query.lua @@ -861,8 +861,8 @@ function Query:iter_captures(node, source, start, stop) local cursor = vim._create_ts_querycursor(node, self.query, start, stop, { match_limit = 256 }) - local apply_directives = memoize(match_id_hash, self.apply_directives, true) - local match_preds = memoize(match_id_hash, self.match_preds, true) + local apply_directives = memoize(match_id_hash, self.apply_directives, false) + local match_preds = memoize(match_id_hash, self.match_preds, false) local function iter(end_line) local capture, captured_node, match = cursor:next_capture() diff --git a/test/functional/func/memoize_spec.lua b/test/functional/func/memoize_spec.lua new file mode 100644 index 0000000000..ca518ab88d --- /dev/null +++ b/test/functional/func/memoize_spec.lua @@ -0,0 +1,142 @@ +local t = require('test.testutil') +local n = require('test.functional.testnvim')() +local clear = n.clear +local exec_lua = n.exec_lua +local eq = t.eq + +describe('vim.func._memoize', function() + before_each(clear) + + it('caches function results based on their parameters', function() + exec_lua([[ + _G.count = 0 + + local adder = vim.func._memoize('concat', function(arg1, arg2) + _G.count = _G.count + 1 + return arg1 + arg2 + end) + + collectgarbage('stop') + adder(3, -4) + adder(3, -4) + adder(3, -4) + adder(3, -4) + adder(3, -4) + collectgarbage('restart') + ]]) + + eq(1, exec_lua([[return _G.count]])) + end) + + it('caches function results using a weak table by default', function() + exec_lua([[ + _G.count = 0 + + local adder = vim.func._memoize('concat-2', function(arg1, arg2) + _G.count = _G.count + 1 + return arg1 + arg2 + end) + + adder(3, -4) + collectgarbage() + adder(3, -4) + collectgarbage() + adder(3, -4) + ]]) + + eq(3, exec_lua([[return _G.count]])) + end) + + it('can cache using a strong table', function() + exec_lua([[ + _G.count = 0 + + local adder = vim.func._memoize('concat-2', function(arg1, arg2) + _G.count = _G.count + 1 + return arg1 + arg2 + end, false) + + adder(3, -4) + collectgarbage() + adder(3, -4) + collectgarbage() + adder(3, -4) + ]]) + + eq(1, exec_lua([[return _G.count]])) + end) + + it('can clear a single cache entry', function() + exec_lua([[ + _G.count = 0 + + local adder = vim.func._memoize(function(arg1, arg2) + return tostring(arg1) .. '%%' .. tostring(arg2) + end, function(arg1, arg2) + _G.count = _G.count + 1 + return arg1 + arg2 + end) + + collectgarbage('stop') + adder(3, -4) + adder(3, -4) + adder(3, -4) + adder(3, -4) + adder(3, -4) + adder:clear(3, -4) + adder(3, -4) + collectgarbage('restart') + ]]) + + eq(2, exec_lua([[return _G.count]])) + end) + + it('can clear the entire cache', function() + exec_lua([[ + _G.count = 0 + + local adder = vim.func._memoize(function(arg1, arg2) + return tostring(arg1) .. '%%' .. tostring(arg2) + end, function(arg1, arg2) + _G.count = _G.count + 1 + return arg1 + arg2 + end) + + collectgarbage('stop') + adder(1, 2) + adder(3, -4) + adder(1, 2) + adder(3, -4) + adder(1, 2) + adder(3, -4) + adder:clear() + adder(1, 2) + adder(3, -4) + collectgarbage('restart') + ]]) + + eq(4, exec_lua([[return _G.count]])) + end) + + it('can cache functions that return nil', function() + exec_lua([[ + _G.count = 0 + + local adder = vim.func._memoize('concat', function(arg1, arg2) + _G.count = _G.count + 1 + return nil + end) + + collectgarbage('stop') + adder(1, 2) + adder(1, 2) + adder(1, 2) + adder(1, 2) + adder:clear() + adder(1, 2) + collectgarbage('restart') + ]]) + + eq(2, exec_lua([[return _G.count]])) + end) +end)