Fix preview support for MS Windows (WSL and Git bash) (#1215)

* Fixes #1212

* Path translation only when containing backslash.

- lower letters also allowed for drive

Co-authored-by: Jan Stocker <Jan.Stocker@cosmoconsult.com>

autoload/fzf/vim.vim

@@ -163,6 +163,12 @@ function! fzf#vim#with_preview(...)
   endif
   if s:is_win
     let is_wsl_bash = exepath('bash') =~? 'Windows[/\\]system32[/\\]bash.exe$'
+    if empty($MSWINHOME)
+      let $MSWINHOME = $HOME
+    endif
+    if is_wsl_bash && $WSLENV !~# '[:]\?MSWINHOME\(\/[^:]*\)\?\(:\|$\)'
+      let $WSLENV = 'MSWINHOME/u:'.$WSLENV
+    endif
     let preview_cmd = 'bash '.(is_wsl_bash
     \ ? substitute(substitute(s:bin.preview, '^\([A-Z]\):', '/mnt/\L\1', ''), '\', '/', 'g')
     \ : escape(s:bin.preview, '\'))

bin/preview.sh

@@ -18,7 +18,7 @@ IFS=':' read -r -a INPUT <<< "$1"
 FILE=${INPUT[0]}
 CENTER=${INPUT[1]}
 
-if [[ $1 =~ ^[A-Z]:\\ ]]; then
+if [[ $1 =~ ^[A-Za-z]:\\ ]]; then
   FILE=$FILE:${INPUT[1]}
   CENTER=${INPUT[2]}
 fi
@@ -28,6 +28,20 @@ if [[ -n "$CENTER" && ! "$CENTER" =~ ^[0-9] ]]; then
 fi
 CENTER=${CENTER/[^0-9]*/}
 
+# MS Win support
+if [[ $FILE =~ '\' ]]; then
+  if [ -z "$MSWINHOME" ]; then
+    MSWINHOME="$HOMEDRIVE$HOMEPATH"
+  fi
+  if grep -qEi "(Microsoft|WSL)" /proc/version &> /dev/null ; then
+    MSWINHOME="${MSWINHOME//\\/\\\\}"
+    FILE="${FILE/#\~\\/$MSWINHOME\\}"
+    FILE=$(wslpath -u "$FILE")
+  elif [ -n "$MSWINHOME" ]; then
+    FILE="${FILE/#\~\\/$MSWINHOME\\}"
+  fi
+fi
+
 FILE="${FILE/#\~\//$HOME/}"
 if [ ! -r "$FILE" ]; then
   echo "File not found ${FILE}"