From 8d5cdbba07f7cae3c7bb8947933737795792fe09 Mon Sep 17 00:00:00 2001
From: David Barnett <dbarnett@google.com>
Date: Sat, 18 Mar 2023 17:07:33 -0600
Subject: [PATCH] Implement codefmt#formatterhelpers#FiletypeMatches.

---
 autoload/codefmt/autopep8.vim            |  2 +-
 autoload/codefmt/black.vim               |  2 +-
 autoload/codefmt/clangformat.vim         | 10 ++++----
 autoload/codefmt/cljstyle.vim            |  2 +-
 autoload/codefmt/dartfmt.vim             |  2 +-
 autoload/codefmt/fish_indent.vim         |  2 +-
 autoload/codefmt/formatterhelpers.vim    | 30 ++++++++++++++++++++++++
 autoload/codefmt/gn.vim                  |  2 +-
 autoload/codefmt/gofmt.vim               |  2 +-
 autoload/codefmt/googlejava.vim          |  2 +-
 autoload/codefmt/isort.vim               |  2 +-
 autoload/codefmt/jsbeautify.vim          |  2 +-
 autoload/codefmt/jsonnetfmt.vim          |  7 ++++--
 autoload/codefmt/ktfmt.vim               |  2 +-
 autoload/codefmt/luaformatterfiveone.vim |  2 +-
 autoload/codefmt/mixformat.vim           |  4 ++--
 autoload/codefmt/nixpkgs_fmt.vim         |  2 +-
 autoload/codefmt/ocamlformat.vim         |  2 +-
 autoload/codefmt/ormolu.vim              |  2 +-
 autoload/codefmt/prettier.vim            |  7 ++++--
 autoload/codefmt/rustfmt.vim             |  2 +-
 autoload/codefmt/shfmt.vim               |  2 +-
 autoload/codefmt/swiftformat.vim         |  2 +-
 autoload/codefmt/yapf.vim                |  2 +-
 autoload/codefmt/zprint.vim              |  2 +-
 doc/codefmt.txt                          | 15 ++++++++++++
 26 files changed, 81 insertions(+), 32 deletions(-)

diff --git a/autoload/codefmt/autopep8.vim b/autoload/codefmt/autopep8.vim
index 6b42b8c..f9ba8a5 100644
--- a/autoload/codefmt/autopep8.vim
+++ b/autoload/codefmt/autopep8.vim
@@ -38,7 +38,7 @@ function! codefmt#autopep8#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'python'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'python')
   endfunction
 
   ""
diff --git a/autoload/codefmt/black.vim b/autoload/codefmt/black.vim
index a8f0628..697554b 100644
--- a/autoload/codefmt/black.vim
+++ b/autoload/codefmt/black.vim
@@ -30,7 +30,7 @@ function! codefmt#black#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'python'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'python')
   endfunction
 
   ""
diff --git a/autoload/codefmt/clangformat.vim b/autoload/codefmt/clangformat.vim
index b5d2f8f..afa6fd2 100644
--- a/autoload/codefmt/clangformat.vim
+++ b/autoload/codefmt/clangformat.vim
@@ -115,16 +115,14 @@ function! codefmt#clangformat#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    if &filetype is# 'c' || &filetype is# 'cpp' ||
-        \ &filetype is# 'proto' || &filetype is# 'javascript' ||
-        \ &filetype is# 'objc' || &filetype is# 'objcpp' ||
-        \ &filetype is# 'typescript' || &filetype is# 'arduino' ||
-        \ &filetype is# 'cuda'
+    if codefmt#formatterhelpers#FiletypeMatches(
+        \ &filetype,
+        \ ['c', 'cpp', 'cuda', 'proto', 'javascript', 'objc', 'objcpp', 'typescript', 'arduino'])
       return 1
     endif
     " Version 3.6 adds support for java
     " http://llvm.org/releases/3.6.0/tools/clang/docs/ReleaseNotes.html
-    return &filetype is# 'java' && s:ClangFormatHasAtLeastVersion([3, 6])
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'java') && s:ClangFormatHasAtLeastVersion([3, 6])
   endfunction
 
   ""
diff --git a/autoload/codefmt/cljstyle.vim b/autoload/codefmt/cljstyle.vim
index bd97e90..0e9fca5 100644
--- a/autoload/codefmt/cljstyle.vim
+++ b/autoload/codefmt/cljstyle.vim
@@ -31,7 +31,7 @@ function! codefmt#cljstyle#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'clojure'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'clojure')
   endfunction
 
   ""
diff --git a/autoload/codefmt/dartfmt.vim b/autoload/codefmt/dartfmt.vim
index f2c0022..6bd98a1 100644
--- a/autoload/codefmt/dartfmt.vim
+++ b/autoload/codefmt/dartfmt.vim
@@ -30,7 +30,7 @@ function! codefmt#dartfmt#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'dart'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'dart')
   endfunction
 
   ""
diff --git a/autoload/codefmt/fish_indent.vim b/autoload/codefmt/fish_indent.vim
index 795b3b4..7b0c78d 100644
--- a/autoload/codefmt/fish_indent.vim
+++ b/autoload/codefmt/fish_indent.vim
@@ -27,7 +27,7 @@ function! codefmt#fish_indent#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'fish'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'fish')
   endfunction
 
   ""
diff --git a/autoload/codefmt/formatterhelpers.vim b/autoload/codefmt/formatterhelpers.vim
index eedfd2f..ebc5d1c 100644
--- a/autoload/codefmt/formatterhelpers.vim
+++ b/autoload/codefmt/formatterhelpers.vim
@@ -16,6 +16,35 @@
 let s:plugin = maktaba#plugin#Get('codefmt')
 
 
+" TODO(google/vim-maktaba#255): Use maktaba's when dropping support for 1.16.0.
+function! s:ValueAsList(Value_or_values) abort
+  return maktaba#value#IsList(a:Value_or_values) ?
+      \ a:Value_or_values : [a:Value_or_values]
+endfunction
+
+
+""
+" @public
+" Checks if the given {filetype} matches {expected} filetype(s).
+"
+" Usage examples: >
+"   if codefmt#formatterhelpers#FiletypeMatches(&filetype, 'c')
+" < >
+"   if codefmt#formatterhelpers#FiletypeMatches(&filetype, ['c', 'cpp'])
+" <
+" @throws WrongType
+function! codefmt#formatterhelpers#FiletypeMatches(filetype, expected) abort
+  call maktaba#ensure#TypeMatchesOneOf(a:expected, ['', ['']])
+  " TODO(#212): Support dot-separated filetype names.
+  let l:expected = s:ValueAsList(a:expected)
+  " TODO(google/vim-maktaba#256): Drop this check when redundant with above.
+  for l:expected_ft in l:expected
+    call maktaba#ensure#IsString(l:expected_ft)
+  endfor
+  return index(l:expected, a:filetype) >= 0
+endfunction
+
+
 ""
 " @public
 " Format lines in the current buffer via a formatter invoked by {cmd}, which
@@ -50,6 +79,7 @@ endfunction
 " code that calls it.
 "
 " @throws ShellError if the {cmd} system call fails
+" @throws WrongType
 function! codefmt#formatterhelpers#AttemptFakeRangeFormatting(
     \ startline, endline, cmd) abort
   call maktaba#ensure#IsNumber(a:startline)
diff --git a/autoload/codefmt/gn.vim b/autoload/codefmt/gn.vim
index 3cfd9db..7d3353d 100644
--- a/autoload/codefmt/gn.vim
+++ b/autoload/codefmt/gn.vim
@@ -31,7 +31,7 @@ function! codefmt#gn#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'gn'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'gn')
   endfunction
 
   ""
diff --git a/autoload/codefmt/gofmt.vim b/autoload/codefmt/gofmt.vim
index da4aad6..723e594 100644
--- a/autoload/codefmt/gofmt.vim
+++ b/autoload/codefmt/gofmt.vim
@@ -30,7 +30,7 @@ function! codefmt#gofmt#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'go'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'go')
   endfunction
 
   ""
diff --git a/autoload/codefmt/googlejava.vim b/autoload/codefmt/googlejava.vim
index 94fba8e..2981821 100644
--- a/autoload/codefmt/googlejava.vim
+++ b/autoload/codefmt/googlejava.vim
@@ -41,7 +41,7 @@ function! codefmt#googlejava#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'java'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'java')
   endfunction
 
   ""
diff --git a/autoload/codefmt/isort.vim b/autoload/codefmt/isort.vim
index 40bf2f0..2e8aa2a 100644
--- a/autoload/codefmt/isort.vim
+++ b/autoload/codefmt/isort.vim
@@ -30,7 +30,7 @@ function! codefmt#isort#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'python'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'python')
   endfunction
 
   ""
diff --git a/autoload/codefmt/jsbeautify.vim b/autoload/codefmt/jsbeautify.vim
index 7ea08c4..b90ef74 100644
--- a/autoload/codefmt/jsbeautify.vim
+++ b/autoload/codefmt/jsbeautify.vim
@@ -70,7 +70,7 @@ function! codefmt#jsbeautify#GetFormatter() abort
     " TODO: Support other compound filetypes like "javascript.*" and "css.*"?
     let l:filetype = substitute(a:filetype, '\m^html\..*', 'html', '')
     for [l:format_name, l:filetypes] in items(self._supported_formats)
-      if index(l:filetypes, l:filetype) >= 0
+      if codefmt#formatterhelpers#FiletypeMatches(l:filetype, l:filetypes)
         return l:format_name
       endif
     endfor
diff --git a/autoload/codefmt/jsonnetfmt.vim b/autoload/codefmt/jsonnetfmt.vim
index f3068b3..a56fe3b 100644
--- a/autoload/codefmt/jsonnetfmt.vim
+++ b/autoload/codefmt/jsonnetfmt.vim
@@ -1,6 +1,9 @@
 let s:plugin = maktaba#plugin#Get('codefmt')
 
-let s:SUPPORTED_FILETYPES = ['json', 'jsonnet']
+if !exists('s:SUPPORTED_FILETYPES')
+  let s:SUPPORTED_FILETYPES = ['json', 'jsonnet']
+  lockvar! s:SUPPORTED_FILETYPES
+endif
 
 
 ""
@@ -17,7 +20,7 @@ function! codefmt#jsonnetfmt#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return index(s:SUPPORTED_FILETYPES, &filetype) >= 0
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, s:SUPPORTED_FILETYPES)
   endfunction
 
   ""
diff --git a/autoload/codefmt/ktfmt.vim b/autoload/codefmt/ktfmt.vim
index 88681eb..c250e4f 100644
--- a/autoload/codefmt/ktfmt.vim
+++ b/autoload/codefmt/ktfmt.vim
@@ -71,7 +71,7 @@ function! codefmt#ktfmt#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'kotlin'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'kotlin')
   endfunction
 
   ""
diff --git a/autoload/codefmt/luaformatterfiveone.vim b/autoload/codefmt/luaformatterfiveone.vim
index 01a8530..732e661 100644
--- a/autoload/codefmt/luaformatterfiveone.vim
+++ b/autoload/codefmt/luaformatterfiveone.vim
@@ -31,7 +31,7 @@ function! codefmt#luaformatterfiveone#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'lua'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'lua')
   endfunction
 
   ""
diff --git a/autoload/codefmt/mixformat.vim b/autoload/codefmt/mixformat.vim
index a24a7ab..d1b6c4b 100644
--- a/autoload/codefmt/mixformat.vim
+++ b/autoload/codefmt/mixformat.vim
@@ -35,8 +35,8 @@ function! codefmt#mixformat#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'elixir' || &filetype is# 'eelixir'
-          \ || &filetype is# 'heex'
+    return codefmt#formatterhelpers#FiletypeMatches(
+        \ &filetype, ['elixir', 'eelixir', 'heex'])
   endfunction
 
   ""
diff --git a/autoload/codefmt/nixpkgs_fmt.vim b/autoload/codefmt/nixpkgs_fmt.vim
index 2046a6b..940a15b 100644
--- a/autoload/codefmt/nixpkgs_fmt.vim
+++ b/autoload/codefmt/nixpkgs_fmt.vim
@@ -31,7 +31,7 @@ function! codefmt#nixpkgs_fmt#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'nix'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'nix')
   endfunction
 
   ""
diff --git a/autoload/codefmt/ocamlformat.vim b/autoload/codefmt/ocamlformat.vim
index 156af9e..01663f7 100644
--- a/autoload/codefmt/ocamlformat.vim
+++ b/autoload/codefmt/ocamlformat.vim
@@ -30,7 +30,7 @@ function! codefmt#ocamlformat#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'ocaml'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'ocaml')
   endfunction
 
   ""
diff --git a/autoload/codefmt/ormolu.vim b/autoload/codefmt/ormolu.vim
index dcdb424..e9be408 100644
--- a/autoload/codefmt/ormolu.vim
+++ b/autoload/codefmt/ormolu.vim
@@ -30,7 +30,7 @@ function! codefmt#ormolu#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'haskell'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'haskell')
   endfunction
 
   ""
diff --git a/autoload/codefmt/prettier.vim b/autoload/codefmt/prettier.vim
index f310dc3..add1f63 100644
--- a/autoload/codefmt/prettier.vim
+++ b/autoload/codefmt/prettier.vim
@@ -16,8 +16,11 @@
 let s:plugin = maktaba#plugin#Get('codefmt')
 
 " See https://prettier.io for a list of supported file types.
-let s:supported_filetypes = ['javascript', 'markdown', 'html', 'css', 'yaml',
+if !exists('s:SUPPORTED_FILETYPES')
+  let s:SUPPORTED_FILETYPES = ['javascript', 'markdown', 'html', 'css', 'yaml',
       \ 'jsx', 'less', 'scss', 'mdx', 'vue']
+  lockvar! s:SUPPORTED_FILETYPES
+endif
 
 
 ""
@@ -56,7 +59,7 @@ function! codefmt#prettier#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return index(s:supported_filetypes, &filetype) >= 0
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, s:SUPPORTED_FILETYPES)
   endfunction
 
   ""
diff --git a/autoload/codefmt/rustfmt.vim b/autoload/codefmt/rustfmt.vim
index 2c0789f..0d7e38a 100644
--- a/autoload/codefmt/rustfmt.vim
+++ b/autoload/codefmt/rustfmt.vim
@@ -31,7 +31,7 @@ function! codefmt#rustfmt#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'rust'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'rust')
   endfunction
 
   ""
diff --git a/autoload/codefmt/shfmt.vim b/autoload/codefmt/shfmt.vim
index c016d35..114263d 100644
--- a/autoload/codefmt/shfmt.vim
+++ b/autoload/codefmt/shfmt.vim
@@ -36,7 +36,7 @@ function! codefmt#shfmt#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'sh'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'sh')
   endfunction
 
   ""
diff --git a/autoload/codefmt/swiftformat.vim b/autoload/codefmt/swiftformat.vim
index 3aa3502..744acc9 100644
--- a/autoload/codefmt/swiftformat.vim
+++ b/autoload/codefmt/swiftformat.vim
@@ -29,7 +29,7 @@ function! codefmt#swiftformat#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'swift'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'swift')
   endfunction
 
   ""
diff --git a/autoload/codefmt/yapf.vim b/autoload/codefmt/yapf.vim
index a415414..1225d00 100644
--- a/autoload/codefmt/yapf.vim
+++ b/autoload/codefmt/yapf.vim
@@ -30,7 +30,7 @@ function! codefmt#yapf#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'python'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'python')
   endfunction
 
   ""
diff --git a/autoload/codefmt/zprint.vim b/autoload/codefmt/zprint.vim
index caf734c..f20a500 100644
--- a/autoload/codefmt/zprint.vim
+++ b/autoload/codefmt/zprint.vim
@@ -44,7 +44,7 @@ function! codefmt#zprint#GetFormatter() abort
   endfunction
 
   function l:formatter.AppliesToBuffer() abort
-    return &filetype is# 'clojure'
+    return codefmt#formatterhelpers#FiletypeMatches(&filetype, 'clojure')
   endfunction
 
   ""
diff --git a/doc/codefmt.txt b/doc/codefmt.txt
index d34c2ee..ce523a5 100644
--- a/doc/codefmt.txt
+++ b/doc/codefmt.txt
@@ -357,6 +357,20 @@ codefmt#FormatMap({type})                                *codefmt#FormatMap()*
   Suitable for use as 'operatorfunc'; see |g@| for details. The type is
   ignored since formatting only works on complete lines.
 
+codefmt#formatterhelpers#FiletypeMatches({filetype}, {expected})
+                                  *codefmt#formatterhelpers#FiletypeMatches()*
+  Checks if the given {filetype} matches {expected} filetype(s).
+
+  Usage examples:
+>
+    if codefmt#formatterhelpers#FiletypeMatches(&filetype, 'c')
+<
+
+>
+    if codefmt#formatterhelpers#FiletypeMatches(&filetype, ['c', 'cpp'])
+<
+  Throws ERROR(WrongType)
+
 codefmt#formatterhelpers#Format({cmd})     *codefmt#formatterhelpers#Format()*
   Format lines in the current buffer via a formatter invoked by {cmd}, which
   is a system call represented by either a |maktaba.Syscall| or any argument
@@ -380,6 +394,7 @@ codefmt#formatterhelpers#AttemptFakeRangeFormatting({startline}, {endline},
   code that calls it.
 
   Throws ERROR(ShellError) if the {cmd} system call fails
+  Throws ERROR(WrongType)
 
 codefmt#formatterhelpers#ResolveFlagToArray({flag_name})
                                *codefmt#formatterhelpers#ResolveFlagToArray()*