From 15bf8fb8f9ba4d7b8d58afc30c4da91d8f80e462 Mon Sep 17 00:00:00 2001
From: Frank Seifferth <frankseifferth@posteo.net>
Date: Tue, 11 May 2021 20:07:10 +0200
Subject: Deactivate pre-save-hooks by default (including docs in readme)

---
 README.md  | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 edconf.lua | 13 +++++++++++++
 2 files changed, 72 insertions(+)

diff --git a/README.md b/README.md
index bc49140..5c1ecef 100644
--- a/README.md
+++ b/README.md
@@ -14,3 +14,62 @@ git clone https://github.com/vktec/vis-editorconfig "$HOME/.config/vis/editorcon
 ```
 
 Then add `require "editorconfig/edconf"` to your `visrc.lua`.
+
+## Functionality
+
+Not all editorconfig functionality is supported by vis and hence by this
+plugin. At this moment, there is full support for the following settings:
+
+- indent_style
+- indent_size
+- tab_width
+- insert_final_newline
+
+The following settings are implemented partially and / or support is
+turned off by default:
+
+- trim_trailing_whitespace: Turned off by default, can be enabled
+  via `:set edconfhooks on`.
+- end_of_line: Turned off by default, partial support can be enabled
+  via `:set edconfhooks on`. Only `crlf` and `lf` are supported, plain
+  `cr` is not. The implementation is also very basic. If end_of_line
+  is set to `crlf`, a return character will be inserted at the end of
+  each line that does not yet end with `crlf`. If end_of_line is set
+  to `lf`, return characters at the end of a line will be stripped.
+  While I would encourage every vis user to stick to `lf` terminated
+  files, this might be convenient if, for some reason, they do need
+  to compose `crlf` terminated files.
+- max_line_length: Turned off by default, partial support can be
+  enabled via `:set edconfhooks on`. There is no straightforward way
+  to automatically wrap content that might be written in arbitrary
+  programming (or non-programming) languages. For that reason,
+  vis-editorconfig doesn't even try. If max_line_length is enabled,
+  vis-editorconfig issues a warning, however, indicating which lines
+  are longer than the specified length. Note that you will miss this
+  warning if you write your file with `:wq`, so if you care about it,
+  write it with `:w<RETURN>:q`.
+
+The reason those last three settings are optional and turned off by
+default is their scalability. Each of those operations is implemented
+as a pre-save-hook with a complexity of O(n), where n is the filesize.
+Since vis is incredibly good at editing huge files efficiently, there
+seems to be a very real danger that those hooks could cause the editor
+to freeze just before a user's valuable changes are written to disk.
+
+You can turn support for those pre-save-hooks on or off at any time
+by running
+
+    :set edconfhooks on
+
+or
+
+    :set edconfhooks off
+
+If `edconfhooks` are enabled, they will be executed as configured in
+`.editorconfig`. If you want to take a less cautious approach and enable
+these hooks by default, simply add an additional line below the module
+import in `visrc.lua`:
+
+    require('editorconfig/edconf')
+    vis:command('set edconfhooks on')   -- supposing you did previously
+                                        -- require('vis')
diff --git a/edconf.lua b/edconf.lua
index 9b5a546..2ec800b 100644
--- a/edconf.lua
+++ b/edconf.lua
@@ -32,12 +32,17 @@ end
 
 -- Custom functionality
 function insert_final_newline(file, path)
+  -- Technically speaking, this is a pre-save-hook as well and could
+  -- therefore respect edconf_hooks_enabled. Since this function runs
+  -- blazingly fast and scales with a complexity of O(1), however,
+  -- there is no need to disable it.
   if file:content(file.size-1, file.size) ~= '\n' then
     file:insert(file.size, '\n')
   end
 end
 
 function trim_trailing_whitespace(file, path)
+  if not edconf_hooks_enabled then return end
   for i=1, #file.lines do
     if string.match(file.lines[i], '[ \t]$') then
       file.lines[i] = string.gsub(file.lines[i], '[ \t]*$', '')
@@ -46,6 +51,7 @@ function trim_trailing_whitespace(file, path)
 end
 
 function enforce_crlf_eol(file, path)
+  if not edconf_hooks_enabled then return end
   for i=1, #file.lines do
     if not string.match(file.lines[i], '\r$') then
       file.lines[i] = string.gsub(file.lines[i], '$', '\r')
@@ -54,6 +60,7 @@ function enforce_crlf_eol(file, path)
 end
 
 function enforce_lf_eol(file, path)
+  if not edconf_hooks_enabled then return end
   for i=1, #file.lines do
     if string.match(file.lines[i], '\r$') then
       file.lines[i] = string.gsub(file.lines[i], '\r$', '')
@@ -65,6 +72,7 @@ global_max_line_length = 80     -- This is ugly, but we do want to use
                                 -- single function that we can register
                                 -- or unregister as needed
 function max_line_length(file, path)
+  if not edconf_hooks_enabled then return end
   local overlong_lines = {}
   for i=1, #file.lines do
     if string.len(file.lines[i]) > global_max_line_length then
@@ -167,3 +175,8 @@ end)
 vis.events.subscribe(vis.events.FILE_SAVE_POST, function (file, path)
   ec_set_values(file.path)
 end)
+
+edconf_hooks_enabled = false
+vis:option_register("edconfhooks", "bool", function(value)
+  edconf_hooks_enabled = value
+end)
-- 
cgit