refactor!: Assert condition before setting timers (#16)

This solves #12

See #16 for more details.

README.md

@@ -103,33 +103,65 @@ EOF
     defer_save = { "InsertLeave", "TextChanged" }, -- vim events that trigger a deferred save (saves after `debounce_delay`)
     cancel_defered_save = { "InsertEnter" }, -- vim events that cancel a pending deferred save
   },
-  -- function that determines whether to save the current buffer or not
+  -- function that takes the buffer handle and determines whether to save the current buffer or not
   -- return true: if buffer is ok to be saved
   -- return false: if it's not ok to be saved
-  condition = function(buf)
-    local fn = vim.fn
-    local utils = require("auto-save.utils.data")
-
-    if
-      fn.getbufvar(buf, "&modifiable") == 1 and
-      utils.not_in(fn.getbufvar(buf, "&filetype"), {}) then
-      return true -- met condition(s), can save
-    end
-    return false -- can't save
-  end,
+  -- if set to `nil` then no specific condition is applied
+  condition = nil,
   write_all_buffers = false, -- write all buffers when the current one meets `condition`
   debounce_delay = 1000, -- delay after which a pending save is executed
   callbacks = { -- functions to be executed at different intervals
     enabling = nil, -- ran when enabling auto-save
     disabling = nil, -- ran when disabling auto-save
-    before_asserting_save = nil, -- ran before checking `condition`
     before_saving = nil, -- ran before doing the actual save
     after_saving = nil -- ran after doing the actual save
   }
 }
 ```
 
-Additionally you may want to set up a key mapping to toggle auto-save:
+#### Condition
+The condition field of the configuration allows the user to exclude **auto-save** from saving specific buffers.
+
+Here is an example using a helper function from `auto-save.utils.data` that disables auto-save for specified file types:
+```lua
+{
+  condition = function(buf)
+    local fn = vim.fn
+    local utils = require("auto-save.utils.data")
+
+    -- don't save for `sql` file types
+    if utils.not_in(fn.getbufvar(buf, "&filetype"), {'sql'}) then
+      return true
+    end
+    return false
+  end
+}
+```
+
+You may also exclude `special-buffers` see (`:h buftype` and `:h special-buffers`):
+```lua
+{
+  condition = function(buf)
+    local fn = vim.fn
+
+    -- don't save for special-buffers
+    if fn.getbufvar(buf, "&buftype") ~= '' then
+      return false
+    end
+    return true
+  end
+}
+```
+
+Buffers that are `nomodifiable` are not saved by default.
+
+### 🪴 Usage
+
+Besides running auto-save at startup (if you have `enabled = true` in your config), you may as well:
+
+- `ASToggle`: toggle auto-save
+
+You may want to set up a key mapping for toggling:
 
 ```lua
 vim.api.nvim_set_keymap("n", "<leader>n", ":ASToggle<CR>", {})
@@ -148,11 +180,6 @@ or as part of the `lazy.nvim` plugin spec:
 
 ```
 
-### 🪴 Usage
-
-Besides running auto-save at startup (if you have `enabled = true` in your config), you may as well:
-
-- `ASToggle`: toggle auto-save
 
 ### 🤝 Contributing
 

lua/auto-save/config.lua

@@ -14,24 +14,16 @@ Config = {
       defer_save = { "InsertLeave", "TextChanged" }, -- vim events that trigger a deferred save (saves after `debounce_delay`)
       cancel_defered_save = { "InsertEnter" }, -- vim events that cancel a pending deferred save
     },
-    -- function that determines whether to save the current buffer or not
+    -- function that takes the buffer handle and determines whether to save the current buffer or not
     -- return true: if buffer is ok to be saved
     -- return false: if it's not ok to be saved
-    condition = function(buf)
-      local fn = vim.fn
-      local utils = require("auto-save.utils.data")
-
-      if fn.getbufvar(buf, "&modifiable") == 1 and utils.not_in(fn.getbufvar(buf, "&filetype"), {}) then
-        return true -- met condition(s), can save
-      end
-      return false -- can't save
-    end,
+    -- if set to `nil` then no specific condition is applied
+    condition = nil,
     write_all_buffers = false, -- write all buffers when the current one meets `condition`
     debounce_delay = 1000, -- delay after which a pending save is executed
     callbacks = { -- functions to be executed at different intervals
       enabling = nil, -- ran when enabling auto-save
       disabling = nil, -- ran when disabling auto-save
-      before_asserting_save = nil, -- ran before checking `condition`
       before_saving = nil, -- ran before doing the actual save
       after_saving = nil, -- ran after doing the actual save
     },

lua/auto-save/init.lua

@@ -52,13 +52,22 @@ local function echo_execution_message()
   end
 end
 
-local function save(buf)
-  callback("before_asserting_save")
-
-  if cnf.opts.condition(buf) == false then
-    return
+--- Determines if the given buffer is modifiable and if the condition from the config yields true for it
+--- @param buf number
+--- @return boolean
+local function should_be_saved(buf)
+  if fn.getbufvar(buf, "&modifiable") ~= 1 then
+    return false
   end
 
+  if cnf.opts.condition ~= nil then
+    return cnf.opts.condition(buf)
+  end
+
+  return true
+end
+
+local function save(buf)
   if not api.nvim_buf_get_option(buf, "modified") then
     return
   end
@@ -86,19 +95,13 @@ local function save(buf)
   end
 end
 
-function M.immediate_save(buf)
-    buf = buf or api.nvim_get_current_buf()
+local function immediate_save(buf)
   cancel_timer(buf)
   save(buf)
 end
 
-
 local save_func = nil
 local function defer_save(buf)
-  -- why is this needed? auto_save_abort is never set to true anyways?
-  -- TODO: remove?
-  g.auto_save_abort = false
-
   -- is it really needed to cache this function
   -- TODO: remove?
   if save_func == nil then
@@ -109,25 +112,31 @@ end
 
 function M.on()
   api.nvim_create_autocmd(cnf.opts.trigger_events.immediate_save, {
-    callback = function (opts)
-        M.immediate_save(opts.buf)
+    callback = function(opts)
+      if should_be_saved(opts.buf) then
+        immediate_save(opts.buf)
+      end
     end,
     group = "AutoSave",
-    desc = "Immediately save a buffer"
+    desc = "Immediately save a buffer",
   })
   api.nvim_create_autocmd(cnf.opts.trigger_events.defer_save, {
     callback = function(opts)
+      if should_be_saved(opts.buf) then
         defer_save(opts.buf)
+      end
     end,
     group = "AutoSave",
-    desc = "Save a buffer after the `debounce_delay`"
+    desc = "Save a buffer after the `debounce_delay`",
   })
   api.nvim_create_autocmd(cnf.opts.trigger_events.cancel_defered_save, {
-    callback = function (opts)
+    callback = function(opts)
+      if should_be_saved(opts.buf) then
         cancel_timer(opts.buf)
+      end
     end,
     group = "AutoSave",
-    desc = "Cancel a pending save timer for a buffer"
+    desc = "Cancel a pending save timer for a buffer",
   })
 
   api.nvim_create_autocmd({ "VimEnter", "ColorScheme", "UIEnter" }, {