Format/prettify xml

ftplugin/xml.vim

@@ -556,6 +556,59 @@ if !exists("*s:MoveCursor")
 	endfunction
 endif
 
+" XML formatter
+if !exists("*s:FormatXML")
+    function! s:FormatXML() range
+        " Save the file type
+        let l:origft = &ft
+
+        " Clean the file type
+        set ft=
+
+        " Add fake initial tag (so we can process multiple top-level elements)
+        exe ":let l:beforeFirstLine=" . a:firstline . "-1"
+        if l:beforeFirstLine < 0
+            let l:beforeFirstLine=0
+        endif
+        exe a:lastline . "put ='</PrettyXML>'"
+        exe l:beforeFirstLine . "put ='<PrettyXML>'"
+        exe ":let l:newLastLine=" . a:lastline . "+2"
+        if l:newLastLine > line('$')
+            let l:newLastLine=line('$')
+        endif
+
+        " Remove XML header
+        exe ":" . a:firstline . "," . a:lastline . "s/<\?xml\\_.*\?>\\_s*//e"
+
+        " Recalculate last line of the edited code
+        let l:newLastLine=search('</PrettyXML>')
+
+        " Execute external formatter
+        exe ":silent " . a:firstline . "," . l:newLastLine . "!xmllint --noblanks --format --recover -"
+
+        " Recalculate first and last lines of the edited code
+        let l:newFirstLine=search('<PrettyXML>')
+        let l:newLastLine=search('</PrettyXML>')
+
+        " Get inner range
+        let l:innerFirstLine=l:newFirstLine+1
+        let l:innerLastLine=l:newLastLine-1
+
+        " Remove extra unnecessary indentation
+        exe ":silent " . l:innerFirstLine . "," . l:innerLastLine "s/^  //e"
+
+        " Remove fake tag
+        exe l:newLastLine . "d"
+        exe l:newFirstLine . "d"
+
+        " Put the cursor at the first line of the edited code
+        exe ":" . l:newFirstLine
+
+        " Restore the file type
+        exe "set ft=" . l:origft
+    endfunction
+endif
+
 " Mappings and Settings.                                             {{{1
 " This makes the '%' jump between the start and end of a single tag.
 setlocal matchpairs+=<:>
@@ -599,6 +652,10 @@ nnoremap <buffer> <LocalLeader>w :call <SID>ClearJumpMarks()<Cr>
 " The syntax files clear out any predefined syntax definitions. Recreate
 " this when ever a xml_jump_string is created. (in ParseTag)
 
+" Format XML
+nnoremap <buffer> <LocalLeader>x :call <SID>FormatXML()<Cr>
+vnoremap <buffer> <LocalLeader>x <Esc>:call <SID>FormatXML()<Cr>
+
 augroup xml
     au!
     au BufNewFile * call <SID>NewFileXML()