fix(modules): do not reattach if already attached

1 files changed, 48 insertions, 0 deletions

diff --git a/lua/nvim-treesitter/caching.lua b/lua/nvim-treesitter/caching.lua
new file mode 100644
index 00000000..bfda3962
--- /dev/null
+++ b/lua/nvim-treesitter/caching.lua
@@ -0,0 +1,48 @@
+local api = vim.api
+
+local M = {}
+
+--- Creates a cache table for buffers keyed by a type name.
+--- Cache entries attach to the buffer and cleanup entries
+--- as buffers are detached.
+function M.create_buffer_cache()
+  local cache = {}
+
+  local items = setmetatable({}, {
+    __index = function(tbl, key)
+      rawset(tbl, key, {})
+      return rawget(tbl, key)
+    end
+  })
+
+  function cache.set(type_name, bufnr, value)
+    if not cache.has(type_name, bufnr) then
+      -- Clean up the cache if the buffer is detached
+      -- to avoid memory leaks
+      api.nvim_buf_attach(bufnr, false, {
+        on_detach = function()
+          cache.remove(type_name, bufnr)
+          return true
+        end
+      })
+    end
+
+    items[type_name][bufnr] = value
+  end
+
+  function cache.get(type_name, bufnr)
+    return items[type_name][bufnr]
+  end
+
+  function cache.has(type_name, bufnr)
+    return cache.get(type_name, bufnr) ~= nil
+  end
+
+  function cache.remove(type_name, bufnr)
+    items[type_name][bufnr] = nil
+  end
+
+  return cache
+end
+
+return M