perf: split caching in state, cache and module

lua/lazy/core/cache.lua

@@ -0,0 +1,109 @@
+-- Simple string cache with fast saving and loading from file
+local M = {}
+
+local cache_path = vim.fn.stdpath("state") .. "/lazy/plugins.state"
+---@type string
+local cache_hash = nil
+local dirty = false
+
+---@type table<string,boolean>
+local used = {}
+
+---@type table<string,string>
+local cache = {}
+
+function M.get(key)
+  if cache[key] then
+    used[key] = true
+    return cache[key]
+  end
+end
+
+function M.set(key, value)
+  cache[key] = value
+  used[key] = true
+  dirty = true
+end
+
+function M.del(key)
+  cache[key] = nil
+  dirty = true
+end
+
+function M.dirty()
+  dirty = true
+end
+
+function M.use(pattern)
+  for key, _ in pairs(cache) do
+    if key:find(pattern) then
+      used[key] = true
+    end
+  end
+end
+
+function M.hash(file)
+  local stat = vim.loop.fs_stat(file)
+  return stat and (stat.mtime.sec .. stat.mtime.nsec .. stat.size)
+end
+
+function M.setup()
+  M.load()
+  vim.api.nvim_create_autocmd("User", {
+    pattern = "LazyDone",
+    once = true,
+    callback = function()
+      vim.api.nvim_create_autocmd("VimLeavePre", {
+        callback = function()
+          if dirty then
+            local hash = M.hash(cache_path)
+            -- abort when the file was changed in the meantime
+            if hash == nil or cache_hash == hash then
+              M.save()
+            end
+          end
+        end,
+      })
+    end,
+  })
+end
+
+function M.save()
+  require("lazy.core.state").save()
+  require("lazy.core.module").save()
+
+  vim.fn.mkdir(vim.fn.fnamemodify(cache_path, ":p:h"), "p")
+  local f = assert(io.open(cache_path, "wb"))
+  for key, value in pairs(cache) do
+    if used[key] then
+      f:write(key, "\0", tostring(#value), "\0", value)
+    end
+  end
+  f:close()
+end
+
+function M.load()
+  cache = {}
+  local f = io.open(cache_path, "rb")
+  if f then
+    cache_hash = M.hash(cache_path)
+    ---@type string
+    local data = f:read("*a")
+    f:close()
+
+    local from = 1
+    local to = data:find("\0", from, true)
+    while to do
+      local key = data:sub(from, to - 1)
+      from = to + 1
+      to = data:find("\0", from, true)
+      local len = tonumber(data:sub(from, to - 1))
+      from = to + 1
+      cache[key] = data:sub(from, from + len - 1)
+      from = from + len
+      to = data:find("\0", from, true)
+    end
+  end
+end
+
+return M