" Vim support file to detect file types in scripts
"
" Maintainer: The Vim Project <https://github.com/vim/vim>
" Last Change: 2023 Aug 27
" Former Maintainer: Bram Moolenaar <Bram@vim.org>
" This file is called by an autocommand for every file that has just been
" loaded into a buffer. It checks if the type of file can be recognized by
" the file contents. The autocommand is in $VIMRUNTIME/filetype.vim.
" Bail out when a FileType autocommand has already set the filetype.
if did_filetype()
finish
endif
" Load the user defined scripts file first
" Only do this when the FileType autocommand has not been triggered yet
if exists("myscriptsfile") && filereadable(expand(myscriptsfile))
execute "source " . myscriptsfile
if did_filetype()
finish
endif
endif
" The main code is in a compiled function for speed.
call dist#script#DetectFiletype()
export def DetectFiletype()
var line1 = getline(1)
if line1[0] == '#' && line1[1] == '!'
# File that starts with "#!".
DetectFromHashBang(line1)
else
# File does not start with "#!".
DetectFromText(line1)
endif
enddef
シェバングで決まればそれで
それでも決まらなければバッファの内容から判定する
という感じ。
autoload/dist/script.vim
の DetectFromText
DetectFromText の方も見ていく。
def DetectFromText(line1: string)
var line2 = getline(2)
var line3 = getline(3)
var line4 = getline(4)
var line5 = getline(5)
...(snip)
先頭 5
行目までを読み込み、この後にファイルタイプ判定処理が続いている。
例えば diff の判定処理は以下。
# Diff file:
# - "diff" in first line (context diff)
# - "Only in " in first line
# - "--- " in first line and "+++ " in second line (unified diff).
# - "*** " in first line and "--- " in second line (context diff).
# - "# It was generated by makepatch " in the second line (makepatch diff).
# - "Index: <filename>" in the first line (CVS file)
# - "=== ", line of "=", "---", "+++ " (SVK diff)
# - "=== ", "--- ", "+++ " (bzr diff, common case)
# - "=== (removed|added|renamed|modified)" (bzr diff, alternative)
# - "# HG changeset patch" in first line (Mercurial export format)
elseif line1 =~ '^\(diff\>\|Only in \|\d\+\(,\d\+\)\=[cda]\d\+\>\|# It was generated by makepatch \|Index:\s\+\f\+\r\=$\|===== \f\+ \d\+\.\d\+ vs edited\|==== //\f\+#\d\+\|# HG changeset patch\)'
|| (line1 =~ '^--- ' && line2 =~ '^+++ ')
|| (line1 =~ '^\* looking for ' && line2 =~ '^\* comparing to ')
|| (line1 =~ '^\*\*\* ' && line2 =~ '^--- ')
|| (line1 =~ '^=== ' && ((line2 =~ '^=\{66\}' && line3 =~ '^--- ' && line4 =~ '^+++') || (line2 =~ '^--- ' && line3 =~ '^+++ ')))
|| (line1 =~ '^=== \(removed\|added\|renamed\|modified\)')
setl ft=diff
Vim のソースを grep したところ、 runtime/filetype.vim
から、 autocmd の BufNewFile,BufRead
で呼び出されているようだ。
" Check for "*" after loading myfiletypefile, so that scripts.vim is only used
" when there are no matching file name extensions.
" Don't do this for compressed files.
augroup filetypedetect
au BufNewFile,BufRead *
\ if !did_filetype() && expand("<amatch>") !~ g:ft_ignore_pat
\ | runtime! scripts.vim | endif
au StdinReadPost * if !did_filetype() | runtime! scripts.vim | endif
