1 files changed, 70 insertions, 0 deletions
diff --git a/autoload/prettier/utils/buffer.vim b/autoload/prettier/utils/buffer.vim
new file mode 100644
index 0000000..7bc7ab1
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+++ b/autoload/prettier/utils/buffer.vim
@@ -0,0 +1,70 @@
+function! prettier#utils#buffer#replace(lines, startSelection, endSelection) abort
+  " store view
+  let l:winview = winsaveview()
+  let l:newBuffer = prettier#utils#buffer#createBufferFromUpdatedLines(a:lines, a:startSelection, a:endSelection)
+
+  " we should not replace contents if the newBuffer is empty
+  if empty(l:newBuffer)
+    return
+  endif
+
+  " https://vim.fandom.com/wiki/Restore_the_cursor_position_after_undoing_text_change_made_by_a_script
+  " create a fake change entry and merge with undo stack prior to do formating
+  normal! ix
+  normal! x
+  try | silent undojoin | catch | endtry
+
+  " delete all lines on the current buffer
+  silent! execute '%delete _'
+
+  " replace all lines from the current buffer with output from prettier
+  let l:idx = 0
+  for l:line in l:newBuffer
+    silent! call append(l:idx, l:line)
+    let l:idx += 1
+  endfor
+  
+  " delete trailing newline introduced by the above append procedure
+  silent! execute '$delete _'
+
+  " Restore view
+  call winrestview(l:winview)
+
+endfunction
+
+" Replace and save the buffer
+function! prettier#utils#buffer#replaceAndSave(lines, startSelection, endSelection) abort
+  call prettier#utils#buffer#replace(a:lines, a:startSelection, a:endSelection)
+  noautocmd write
+endfunction
+
+" Returns 1 if content has changed
+function! prettier#utils#buffer#willUpdatedLinesChangeBuffer(lines, start, end) abort
+  return getbufline(bufnr('%'), 1, line('$')) == prettier#utils#buffer#createBufferFromUpdatedLines(a:lines, a:start, a:end) ? 0 : 1
+endfunction
+
+" Returns a new buffer with lines replacing start and end of the contents of the current buffer
+function! prettier#utils#buffer#createBufferFromUpdatedLines(lines, start, end) abort
+  return getbufline(bufnr('%'), 1, a:start - 1) + a:lines + getbufline(bufnr('%'), a:end + 1, '$')
+endfunction
+
+" Adapted from https://github.com/farazdagi/vim-go-ide
+function! s:getCharPosition(line, col) abort
+    if &encoding !=# 'utf-8'
+        " On utf-8 enconding we can't just use bytes so we need to make sure we can count the
+        " characters, we do that by adding the text into a temporary buffer and counting the chars
+        let l:buf = a:line == 1 ? '' : (join(getline(1, a:line - 1), "\n") . "\n")
+        let l:buf .= a:col == 1 ? '' : getline('.')[:a:col - 2]
+        return len(iconv(l:buf, &encoding, 'utf-8'))
+    endif
+    " On non utf-8 the line byte should match the character
+    return line2byte(a:line) + (a:col - 2)
+endfun
+
+" Returns [start, end] byte range when on visual mode
+function! prettier#utils#buffer#getCharRange(startSelection, endSelection) abort
+  let l:range = []
+  call add(l:range, s:getCharPosition(a:startSelection, col("'<")))
+  call add(l:range, s:getCharPosition(a:endSelection, col("'>")))
+  return l:range
+endfunction