preview information shown in hover at the cursor (#395)

* preview information shown in hover at the cursor

* lint

* Fix hover float positioning

* Integrate vim8.1 popup for hover/preview

* lint

* Fix hover float positioning above cursor line

* Closing and focusing floating preview (nvim)

* Renamed variable of preview window id

* autocmd events for open/close floats

* Closing of floating preview & lightlinefix (vim8.1)

* Added doubletap functionality to preview

autoload/lsp.vim

@@ -26,6 +26,8 @@ augroup _lsp_silent_
     autocmd User lsp_server_init silent
     autocmd User lsp_server_exit silent
     autocmd User lsp_complete_done silent
+    autocmd User lsp_float_opened silent
+    autocmd User lsp_float_closed silent
 augroup END
 
 function! lsp#log_verbose(...) abort

autoload/lsp/ui/vim/output.vim

@@ -1,18 +1,206 @@
+let s:supports_floating = exists('*nvim_open_win') || has('patch-8.1.1517')
+let s:winid = v:false
+let s:prevwin = v:false
+let s:preview_data = v:false
+
+function! lsp#ui#vim#output#closepreview() abort
+  if win_getid() == s:winid
+    " Don't close if window got focus
+    return
+  endif
+  "closing floats in vim8.1 must use popup_close() (nvim could use nvim_win_close but pclose
+  "works)
+  if s:supports_floating && s:winid && g:lsp_preview_float && !has('nvim')
+    call popup_close(s:winid)
+  else
+    pclose
+  endif
+  let s:winid = v:false
+  let s:preview_data = v:false
+  augroup lsp_float_preview_close
+  augroup end
+  autocmd! lsp_float_preview_close CursorMoved,CursorMovedI,VimResized *
+  doautocmd User lsp_float_closed
+endfunction
+
+function! lsp#ui#vim#output#focuspreview() abort
+  " This does not work for vim8.1 popup but will work for nvim and old preview
+  if s:winid
+    if win_getid() != s:winid
+      let s:prevwin = win_getid()
+      call win_gotoid(s:winid)
+    elseif s:prevwin
+      " Temporarily disable hooks
+      " TODO: remove this when closing logic is able to distinguish different move directions
+      autocmd! lsp_float_preview_close CursorMoved,CursorMovedI,VimResized *
+      call win_gotoid(s:prevwin)
+      call s:add_float_closing_hooks()
+      let s:prevwin = v:false
+    endif
+  endif
+endfunction
+
+function! s:bufwidth() abort
+  let width = winwidth(0)
+  let numberwidth = max([&numberwidth, strlen(line('$'))+1])
+  let numwidth = (&number || &relativenumber)? numberwidth : 0
+  let foldwidth = &foldcolumn
+
+  if &signcolumn ==? 'yes'
+    let signwidth = 2
+  elseif &signcolumn ==? 'auto'
+    let signs = execute(printf('sign place buffer=%d', bufnr('')))
+    let signs = split(signs, "\n")
+    let signwidth = len(signs)>2? 2: 0
+  else
+    let signwidth = 0
+  endif
+  return width - numwidth - foldwidth - signwidth
+endfunction
+
+
+function! s:get_float_positioning(height, width) abort
+    let l:height = a:height
+    let l:width = a:width
+    " For a start show it below/above the cursor
+    " TODO: add option to configure it 'docked' at the bottom/top/right
+    let l:y = winline()
+    if l:y + l:height >= winheight(0)
+      " Float does not fit
+      if l:y - 2 > l:height
+        " Fits above
+        let l:y = winline() - l:height -1
+      elseif l:y - 2 > winheight(0) - l:y
+        " Take space above cursor
+        let l:y = 1
+        let l:height = winline()-2
+      else
+        " Take space below cursor
+        let l:height = winheight(0) -l:y
+      endif
+    endif
+    let l:col = col('.')
+    " Positioning is not window but screen relative
+    let l:opts = {
+          \ 'relative': 'win',
+          \ 'row': l:y,
+          \ 'col': l:col,
+          \ 'width': l:width,
+          \ 'height': l:height,
+          \ }
+    return l:opts
+endfunction
+
+function! lsp#ui#vim#output#floatingpreview(data) abort
+  if has('nvim')
+    let l:buf = nvim_create_buf(v:false, v:true)
+    call setbufvar(l:buf, '&signcolumn', 'no')
+
+    " Try to get as much pace right-bolow the cursor, but at least 10x10
+    let l:width = max([s:bufwidth(), 10])
+    let l:height = max([&lines - winline() + 1, 10])
+
+    let l:opts = s:get_float_positioning(l:height, l:width)
+
+    let s:winid = nvim_open_win(buf, v:true, l:opts)
+    call nvim_win_set_option(s:winid, 'winhl', 'Normal:Pmenu,NormalNC:Pmenu')
+    call nvim_win_set_option(s:winid, 'foldenable', v:false)
+    call nvim_win_set_option(s:winid, 'wrap', v:true)
+    call nvim_win_set_option(s:winid, 'statusline', '')
+    call nvim_win_set_option(s:winid, 'number', v:false)
+    call nvim_win_set_option(s:winid, 'relativenumber', v:false)
+    call nvim_win_set_option(s:winid, 'cursorline', v:false)
+    " Enable closing the preview with esc, but map only in the scratch buffer
+    nmap <buffer><silent> <esc> :pclose<cr>
+  else
+    let s:winid = popup_atcursor('...', {
+        \  'moved': 'any',
+		    \  'border': [1, 1, 1, 1],
+		\})
+  endif
+  return s:winid
+endfunction
+
+function! s:setcontent(lines, ft) abort
+  if s:supports_floating && g:lsp_preview_float && !has('nvim')
+    " vim popup
+    call setbufline(winbufnr(s:winid), 1, a:lines)
+    let l:lightline_toggle = v:false
+    if exists('#lightline') && !has('nvim')
+      " Lightline does not work in popups but does not recognize it yet.
+      " It is ugly to have an check for an other plugin here, better fix lightline...
+      let l:lightline_toggle = v:true
+      call lightline#disable()
+    endif
+    call win_execute(s:winid, 'setlocal filetype=' . a:ft . '.lsp-hover')
+    if l:lightline_toggle
+      call lightline#enable()
+    endif
+  else
+    " nvim floating
+    call setline(1, a:lines)
+    setlocal readonly nomodifiable
+    let &l:filetype = a:ft . '.lsp-hover'
+  endif
+endfunction
+
+function! s:adjust_float_placement(bufferlines, maxwidth) abort
+    if has('nvim')
+      let l:win_config = {}
+      let l:height = min([winheight(s:winid), a:bufferlines])
+      let l:width = min([winwidth(s:winid), a:maxwidth])
+      let l:win_config = s:get_float_positioning(l:height, l:width)
+      call nvim_win_set_config(s:winid, l:win_config )
+    endif
+endfunction
+
+function! s:add_float_closing_hooks() abort
+    if g:lsp_preview_autoclose
+      augroup lsp_float_preview_close
+        autocmd! lsp_float_preview_close CursorMoved,CursorMovedI,VimResized *
+        autocmd CursorMoved,CursorMovedI,VimResized * call lsp#ui#vim#output#closepreview()
+      augroup END
+    endif
+endfunction
+
+function! lsp#ui#vim#output#getpreviewwinid() abort
+    return s:winid
+endfunction
+
+function! s:open_preview(data) abort
+    if s:supports_floating && g:lsp_preview_float
+      let l:winid = lsp#ui#vim#output#floatingpreview(a:data)
+    else
+      execute &previewheight.'new'
+      let l:winid = win_getid()
+    endif
+    return l:winid
+endfunction
+
 function! lsp#ui#vim#output#preview(data) abort
+    if s:winid && type(s:preview_data) == type(a:data)
+       \ && s:preview_data == a:data
+       \ && type(g:lsp_preview_doubletap) == 3
+       \ && len(g:lsp_preview_doubletap) >= 1
+       \ && type(g:lsp_preview_doubletap[0]) == 2
+        echo ''
+        return call(g:lsp_preview_doubletap[0], [])
+    endif
     " Close any previously opened preview window
     pclose
 
     let l:current_window_id = win_getid()
 
-    execute &previewheight.'new'
-
-    let l:ft = s:append(a:data)
-    " Delete first empty line
-    0delete _
+    let s:winid = s:open_preview(a:data)
 
-    setlocal readonly nomodifiable
+    let s:preview_data = a:data
+    let l:lines = []
+    let l:ft = s:append(a:data, l:lines)
+    call s:setcontent(l:lines, l:ft)
 
-    let &l:filetype = l:ft . '.lsp-hover'
+    " Get size information while still having the buffer active
+    let l:bufferlines = line('$')
+    let l:maxwidth = max(map(getline(1, '$'), 'strdisplaywidth(v:val)'))
 
     if g:lsp_preview_keep_focus
       " restore focus to the previous window
@@ -21,28 +209,35 @@ function! lsp#ui#vim#output#preview(data) abort
 
     echo ''
 
+    if s:supports_floating && s:winid && g:lsp_preview_float
+      if has('nvim')
+        call s:adjust_float_placement(l:bufferlines, l:maxwidth)
+        call s:add_float_closing_hooks()
+      endif
+      doautocmd User lsp_float_opened
+    endif
     return ''
 endfunction
 
-function! s:append(data) abort
+function! s:append(data, lines) abort
     if type(a:data) == type([])
         for l:entry in a:data
-            call s:append(entry)
+            call s:append(entry, a:lines)
         endfor
 
         return 'markdown'
     elseif type(a:data) == type('')
-        silent put =a:data
+        call extend(a:lines, split(a:data, "\n"))
 
         return 'markdown'
     elseif type(a:data) == type({}) && has_key(a:data, 'language')
-        silent put ='```'.a:data.language
-        silent put =a:data.value
-        silent put ='```'
+        call add(a:lines, '```'.a:data.language)
+        call extend(a:lines, split(a:data.value, '\n'))
+        call add(a:lines, '```')
 
         return 'markdown'
     elseif type(a:data) == type({}) && has_key(a:data, 'kind')
-        silent put =a:data.value
+        call add(a:lines, a:data.value)
 
         return a:data.kind ==? 'plaintext' ? 'text' : a:data.kind
     endif

doc/vim-lsp.txt

@@ -13,6 +13,9 @@ CONTENTS                                                  *vim-lsp-contents*
       g:lsp_diagnostics_enabled             |g:lsp_diagnostics_enabled|
       g:lsp_auto_enable                     |g:lsp_auto_enable|
       g:lsp_preview_keep_focus              |g:lsp_preview_keep_focus|
+      g:lsp_preview_float		    |g:lsp_preview_float|
+      g:lsp_preview_autoclose		    |g:lsp_preview_autoclose|
+      g:lsp_preview_doubletap		    |g:lsp_preview_doubletap|
       g:lsp_insert_text_enabled             |g:lsp_insert_text_enabled|
       g:lsp_text_edit_enabled               |g:lsp_text_edit_enabled|
       g:lsp_diagnostics_echo_cursor         |g:lsp_diagnostics_echo_cursor|
@@ -53,6 +56,9 @@ CONTENTS                                                  *vim-lsp-contents*
     Autocommands                          |vim-lsp-autocommands|
       lsp_complete_done                     |lsp_complete_done|
     Mappings                              |vim-lsp-mappings|
+       <plug>(lsp-preview-close)            |<plug>(lsp-preview-close)|
+       <plug>(lsp-preview-focus)            |<plug>(lsp-preview-focus)|
+
     Autocomplete                          |vim-lsp-autocomplete|
       omnifunc                              |vim-lsp-omnifunc|
       asyncomplete.vim                      |vim-lsp-asyncomplete|
@@ -154,6 +160,68 @@ g:lsp_preview_keep_focus                         *g:lsp_preview_keep_focus*
 
     * |preview-window| can be closed using the default vim mapping - `<c-w><c-z>`.
 
+g:lsp_preview_float                         *g:lsp_preview_float*
+    Type: |Number|
+    Default: `1`
+
+    If set and nvim_win_open() or popup_create is available, hover information
+    are shown in a floating window as |preview-window| at the cursor position.
+    The |preview-window| is closed automatically on cursor moves, unless it is
+    focused. While focused it may be closed with <esc>.
+    After opening an autocmd User event lsp_float_opened is issued, as well as
+    and lsp_float_closed upon closing. This can be used to alter the preview
+    window (using lsp#ui#vim#output#getpreviewwinid() to get the window id), or
+    setup custom bindings while a preview is open.
+    This feature requires neovim 0.4.0 (current master) or
+    Vim8.1 with has('patch-8.1.1517').
+
+    Example:
+	" Opens preview windows as floating
+	let g:lsp_preview_float = 1
+
+	" Opens preview windows as normal windows
+	let g:lsp_preview_float = 0
+
+	" Close preview window with <esc>
+	autocmd User lsp_float_opened nmap <buffer> <silent> <esc>
+		      \ <Plug>(lsp-preview-close)
+	autocmd User lsp_float_closed nunmap <buffer> <esc>
+
+g:lsp_preview_autoclose                         *g:lsp_preview_autoclose*
+    Type: |Number|
+    Default: `1`
+
+    Indicates if an opened floating preview shall be automatically closed upon
+    movement of the cursor. If set to 1, the window will close automatically if
+    the cursor is moved and the preview is not focused. If set to 0, it will
+    remain open until explicitly closed (e.g. with <plug>(lsp-preview-close),
+    or <ESC> when focused).
+
+    Example:
+	" Preview closes on cursor move
+	let g:lsp_preview_autoclose = 1
+
+	" Preview remains open and waits for an explicit call
+	let g:lsp_preview_autoclose = 0
+
+g:lsp_preview_doubletap                         *g:lsp_preview_doubletap*
+    Type: |List|
+    Default: `[function('lsp#ui#vim#output#focuspreview')]`
+
+    When preview is called twice with the same data while the preview is still
+    open, the function in `lsp_preview_doubletap` is called instead. To disable
+    this and just "refresh" the preview, set to ´0´.
+
+    Example:
+	" Focus preview on repeated preview (does not work for vim8.1 popups)
+	let g:lsp_preview_doubletap = [function('lsp#ui#vim#output#focuspreview')]
+
+	" Closes the preview window on the second call to preview
+	let g:lsp_preview_doubletap = [function('lsp#ui#vim#output#closepreview')]
+
+	" Disables double tap feature; refreshes the preview on consecutive taps
+	let g:lsp_preview_doubletap = 0
+
 g:lsp_insert_text_enabled                       *g:lsp_insert_text_enabled*
     Type: |Number|
     Default: `1`
@@ -566,6 +634,9 @@ Gets the hover information and displays it in the |preview-window|.
  * |preview-window| can be closed using the default vim mapping - `<c-w><c-z>`.
  * To control the default focus of |preview-window| for |LspHover|
    configure |g:lsp_preview_keep_focus|.
+ * If using neovim with nvim_win_open() available, |g:lsp_preview_float| can be
+   set to enable a floating preview at the cursor which is closed automatically
+   on cursormove if not focused and can be closed with <esc> if focused.
 
 
 LspNextError						     *LspNextError*
@@ -640,6 +711,8 @@ Available plug mappings are following:
   (lsp-hover)
   (lsp-next-error)
   (lsp-next-reference)
+  (lsp-preview-close)
+  (lsp-preview-focus)
   (lsp-previous-error)
   (lsp-previous-reference)
   (lsp-references)
@@ -653,6 +726,16 @@ Available plug mappings are following:
 
 See also |vim-lsp-commands|
 
+<plug>(lsp-preview-close)	         	     *<plug>(lsp-preview-close)*
+
+Closes an opened preview window
+
+<plug>(lsp-preview-focus)	         	     *<plug>(lsp-preview-focus)*
+
+Transfers focus to an opened preview window or back to the previous window if
+focus is already on the preview window.
+
+
 ===============================================================================
 Autocomplete                                          *vim-lsp-autocomplete*