I broke up with neovim....vim is my best friend now

dot_vim/plugged/vim-lsp/autoload/lsp/ui/vim/folding.vim

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+let s:folding_ranges = {}
+let s:textprop_name = 'vim-lsp-folding-linenr'
+
+function! s:find_servers() abort
+    return filter(lsp#get_allowed_servers(), 'lsp#capabilities#has_folding_range_provider(v:val)')
+endfunction
+
+function! lsp#ui#vim#folding#fold(sync) abort
+    let l:servers = s:find_servers()
+
+    if len(l:servers) == 0
+        call lsp#utils#error('Folding not supported for ' . &filetype)
+        return
+    endif
+
+    let l:server = l:servers[0]
+    call lsp#ui#vim#folding#send_request(l:server, bufnr('%'), a:sync)
+endfunction
+
+function! s:set_textprops(buf) abort
+    " Use zero-width text properties to act as a sort of "mark" in the buffer.
+    " This is used to remember the line numbers at the time the request was
+    " sent. We will let Vim handle updating the line numbers when the user
+    " inserts or deletes text.
+
+    " Skip if the buffer doesn't exist. This might happen when a buffer is
+    " opened and quickly deleted.
+    if !bufloaded(a:buf) | return | endif
+
+    " Create text property, if not already defined
+    silent! call prop_type_add(s:textprop_name, {'bufnr': a:buf, 'priority': lsp#internal#textprop#priority('folding')})
+
+    let l:line_count = s:get_line_count_buf(a:buf)
+
+    " First, clear all markers from the previous run
+    call prop_remove({'type': s:textprop_name, 'bufnr': a:buf}, 1, l:line_count)
+
+    " Add markers to each line
+    let l:i = 1
+    while l:i <= l:line_count
+        call prop_add(l:i, 1, {'bufnr': a:buf, 'type': s:textprop_name, 'id': l:i})
+        let l:i += 1
+    endwhile
+endfunction
+
+function! s:get_line_count_buf(buf) abort
+    if !has('patch-8.1.1967')
+        return line('$')
+    endif
+    let l:winids = win_findbuf(a:buf)
+    return empty(l:winids) ? line('$') : line('$', l:winids[0])
+endfunction
+
+function! lsp#ui#vim#folding#send_request(server_name, buf, sync) abort
+    if !lsp#capabilities#has_folding_range_provider(a:server_name)
+        return
+    endif
+
+    if !g:lsp_fold_enabled
+        call lsp#log('Skip sending fold request: folding was disabled explicitly')
+        return
+    endif
+
+    if has('textprop')
+        call s:set_textprops(a:buf)
+    endif
+
+    call lsp#send_request(a:server_name, {
+                \ 'method': 'textDocument/foldingRange',
+                \ 'params': {
+                \   'textDocument': lsp#get_text_document_identifier(a:buf)
+                \ },
+                \ 'on_notification': function('s:handle_fold_request', [a:server_name]),
+                \ 'sync': a:sync,
+                \ 'bufnr': a:buf
+                \ })
+endfunction
+
+function! s:foldexpr(server, buf, linenr) abort
+    let l:foldlevel = 0
+    let l:prefix = ''
+
+    for l:folding_range in s:folding_ranges[a:server][a:buf]
+        if type(l:folding_range) == type({}) &&
+         \ has_key(l:folding_range, 'startLine') &&
+         \ has_key(l:folding_range, 'endLine')
+            let l:start = l:folding_range['startLine'] + 1
+            let l:end = l:folding_range['endLine'] + 1
+
+            if (l:start <= a:linenr) && (a:linenr <= l:end)
+                let l:foldlevel += 1
+            endif
+
+            if l:start == a:linenr
+                let l:prefix = '>'
+            elseif l:end == a:linenr
+                let l:prefix = '<'
+            endif
+        endif
+    endfor
+
+    " Only return marker if a fold starts/ends at this line.
+    " Otherwise, return '='.
+    return (l:prefix ==# '') ? '=' : (l:prefix . l:foldlevel)
+endfunction
+
+" Searches for text property of the correct type on the given line.
+" Returns the original linenr on success, or -1 if no textprop of the correct
+" type is associated with this line.
+function! s:get_textprop_line(linenr) abort
+    let l:props = filter(prop_list(a:linenr), {idx, prop -> prop['type'] ==# s:textprop_name})
+
+    if empty(l:props)
+        return -1
+    else
+        return l:props[0]['id']
+    endif
+endfunction
+
+function! lsp#ui#vim#folding#foldexpr() abort
+    let l:servers = s:find_servers()
+
+    if len(l:servers) == 0
+        return
+    endif
+
+    let l:server = l:servers[0]
+
+    if has('textprop')
+        " Does the current line have a textprop with original line info?
+        let l:textprop_line = s:get_textprop_line(v:lnum)
+
+        if l:textprop_line == -1
+            " No information for current line available, so use indent for
+            " previous line.
+            return '='
+        else
+            " Info available, use foldexpr as it would be with original line
+            " number
+            return s:foldexpr(l:server, bufnr('%'), l:textprop_line)
+        endif
+    else
+        return s:foldexpr(l:server, bufnr('%'), v:lnum)
+    endif
+endfunction
+
+function! lsp#ui#vim#folding#foldtext() abort
+    let l:num_lines = v:foldend - v:foldstart + 1
+    let l:summary = getline(v:foldstart) . '...'
+
+    " Join all lines in the fold
+    let l:combined_lines = ''
+    let l:i = v:foldstart
+    while l:i <= v:foldend
+        let l:combined_lines .= getline(l:i) . ' '
+        let l:i += 1
+    endwhile
+
+    " Check if we're in a comment
+    let l:comment_regex = '\V' . substitute(&l:commentstring, '%s', '\\.\\*', '')
+    if l:combined_lines =~? l:comment_regex
+        let l:summary = l:combined_lines
+    endif
+
+    return l:summary . ' (' . l:num_lines . ' ' . (l:num_lines == 1 ? 'line' : 'lines') . ') '
+endfunction
+
+function! s:handle_fold_request(server, data) abort
+    if lsp#client#is_error(a:data) || !has_key(a:data, 'response') || !has_key(a:data['response'], 'result')
+        return
+    endif
+
+    let l:result = a:data['response']['result']
+
+    if type(l:result) != type([])
+        return
+    endif
+
+    let l:uri = a:data['request']['params']['textDocument']['uri']
+    let l:path = lsp#utils#uri_to_path(l:uri)
+    let l:bufnr = bufnr(l:path)
+
+    if l:bufnr < 0
+        return
+    endif
+
+    if !has_key(s:folding_ranges, a:server)
+        let s:folding_ranges[a:server] = {}
+    endif
+    let s:folding_ranges[a:server][l:bufnr] = l:result
+
+    " Set 'foldmethod' back to 'expr', which forces a re-evaluation of
+    " 'foldexpr'. Only do this if the user hasn't changed 'foldmethod',
+    " and this is the correct buffer.
+    for l:winid in win_findbuf(l:bufnr)
+        if getwinvar(l:winid, '&foldmethod') ==# 'expr'
+            call setwinvar(l:winid, '&foldmethod', 'expr')
+        endif
+    endfor
+endfunction
+