Improve diagnostics float implementation (#1296)

Co-authored-by: hrsh7th <>
Co-authored-by: mattn <mattn.jp@gmail.com>

autoload/lsp/internal/diagnostics/float.vim

@@ -1,6 +1,12 @@
 " internal state for whether it is enabled or not to avoid multiple subscriptions
 let s:enabled = 0
 
+let s:Markdown = vital#lsp#import('VS.Vim.Syntax.Markdown')
+let s:MarkupContent = vital#lsp#import('VS.LSP.MarkupContent')
+let s:FloatingWindow = vital#lsp#import('VS.Vim.Window.FloatingWindow')
+let s:Window = vital#lsp#import('VS.Vim.Window')
+let s:Buffer = vital#lsp#import('VS.Vim.Buffer')
+
 function! lsp#internal#diagnostics#float#_enable() abort
     " don't even bother registering if the feature is disabled
     if !lsp#ui#vim#output#float_supported() | return | endif
@@ -12,6 +18,7 @@ function! lsp#internal#diagnostics#float#_enable() abort
     let s:Dispose = lsp#callbag#pipe(
         \ lsp#callbag#fromEvent('CursorMoved'),
         \ lsp#callbag#filter({_->g:lsp_diagnostics_float_cursor}),
+        \ lsp#callbag#tap({_->s:hide_float()}),
         \ lsp#callbag#debounceTime(g:lsp_diagnostics_float_delay),
         \ lsp#callbag#map({_->{'bufnr': bufnr('%'), 'curpos': getcurpos()[0:2], 'changedtick': b:changedtick }}),
         \ lsp#callbag#distinctUntilChanged({a,b -> a['bufnr'] == b['bufnr'] && a['curpos'] == b['curpos'] && a['changedtick'] == b['changedtick']}),
@@ -32,14 +39,72 @@ function! lsp#internal#diagnostics#float#_disable() abort
 endfunction
 
 function! s:show_float(diagnostic) abort
+    let l:doc_win = s:get_doc_win()
     if !empty(a:diagnostic) && has_key(a:diagnostic, 'message')
-        let l:lines = split(a:diagnostic['message'], '\n', 1)
+        " Update contents. 
-        call lsp#ui#vim#output#preview('', l:lines, {
+        call deletebufline(l:doc_win.get_bufnr(), 1, '$')
-            \   'statusline': ' LSP Diagnostics'
+        call setbufline(l:doc_win.get_bufnr(), 1, lsp#utils#_split_by_eol(a:diagnostic['message']))
-            \})
+
-        let s:displaying_message = 1
+        " Compute size. 
-    elseif get(s:, 'displaying_message', 0)
+        let l:size = l:doc_win.get_size({
-        call lsp#ui#vim#output#closepreview()
+        \   'maxwidth': float2nr(&columns * 0.4),
-        let s:displaying_message = 0
+        \   'maxheight': float2nr(&lines * 0.4),
+        \ })
+
+        " Compute position.
+        let l:pos = s:compute_position(l:size)
+
+        " Open window. 
+        call l:doc_win.open({
+        \   'row': l:pos[0],
+        \   'col': l:pos[1],
+        \   'width': l:size.width,
+        \   'height': l:size.height,
+        \   'border': v:true,
+        \   'topline': 1,
+        \ })
+    else
+        call s:hide_float()
     endif
 endfunction
+
+function! s:hide_float() abort
+    let l:doc_win = s:get_doc_win()
+    call l:doc_win.close()
+endfunction
+
+function! s:get_doc_win() abort
+    if exists('s:doc_win')
+        return s:doc_win
+    endif
+
+    let s:doc_win = s:FloatingWindow.new({
+    \   'on_opened': { -> execute('doautocmd <nomodeline> User lsp_float_opened') },
+    \   'on_closed': { -> execute('doautocmd <nomodeline> User lsp_float_closed') }
+    \ })
+    call s:doc_win.set_var('&wrap', 1)
+    call s:doc_win.set_var('&conceallevel', 2)
+    noautocmd silent let l:bufnr = s:Buffer.create()
+    call s:doc_win.set_bufnr(l:bufnr)
+    call setbufvar(s:doc_win.get_bufnr(), '&buftype', 'nofile')
+    call setbufvar(s:doc_win.get_bufnr(), '&bufhidden', 'hide')
+    call setbufvar(s:doc_win.get_bufnr(), '&buflisted', 0)
+    call setbufvar(s:doc_win.get_bufnr(), '&swapfile', 0)
+    return s:doc_win
+endfunction
+
+function! s:compute_position(size) abort
+    let l:pos = screenpos(0, line('.'), col('.'))
+    if l:pos.row == 0 && l:pos.col == 0
+        " When the specified position is not visible
+        return []
+    endif
+    let l:pos = [l:pos.row + 1, l:pos.curscol + 1]
+    if l:pos[0] + a:size.height > &lines
+        let l:pos[0] = l:pos[0] - a:size.height - 3
+    endif
+    if l:pos[1] + a:size.width > &columns
+        let l:pos[1] = l:pos[1] - a:size.width - 3
+    endif
+    return l:pos
+endfunction