[Bash-autocompletion] Add support for older bash version.

[yamaguchi]

Summary

OS X seems to use older bash version which doesn't suport
_init_completion and compopt, so add support for this.

[yamaguchi]

Update patch and diff.

[ruiu]

clang/utils/bash-autocomplete.sh

3

Is the output of compgen -f the same as _filedir? If so, can you always use compgen -f?

7

Let's be consistent on spacing. Please add a space after -f.

15

Likewise, add a space after 2>.

60

Is it okay to use compopt here? (I wonder how does this line work on macOS.)

[yamaguchi]

clang/utils/bash-autocomplete.sh

3

_filedir is better than compgen -f, because it honors spaces in filenames.

60

I thought it will just emit errors and proceed to next line. This part doesn't make a big difference in completion, so I thought we can just ignore it when compopt is not supported.

[yamaguchi]

Update diff.

[ruiu]

clang/utils/bash-autocomplete.sh

3

You want to describe it in a comment: _filedir function provided by recent versions of bash-completion package is better than "compgen -f" because the former honors spaces in pathnames while the latter doesn't. So we use compgen only when _filedir is not provided.

17–18

It's not clear what this code does. Can you explain?

[yamaguchi]

Update diff.

[ruiu]

clang/utils/bash-autocomplete.sh

8–9

If this works, you can probably make it shorter

_filedir 2> /dev/null || COMPREPLY=...

[yamaguchi]

Update patch.

[ruiu]

LGTM

[v.g.vassilev]

It looks like this works with bash 3.2. I've tested this on mac and it works well.

[yamaguchi]

_get_comp_words_by_ref still depends on older bash-completion package, so delete this and set cword and cur manualy.

[ruiu]

LGTM. Confirmed that it works as expected on my Mac which doesn't have the bash-autocomplete package.

clang/utils/bash-autocomplete.sh

19

I think you want to quote $COMP_WORD with "" so that it works even if $COMP_WORD contains space characters.
20

[teemperor]

LGTM, everything still works in the latest bash on Linux.

Also thanks for the reviews Rui!

clang/utils/bash-autocomplete.sh

 # Please add "source /path/to/bash-autocomplete.sh" to your .bashrc to use this.
+
+_clang_filedir()
+{
+  # _filedir function provided by recent versions of bash-completion package is
+  # better than "compgen -f" because the former honors spaces in pathnames while
+  # the latter doesn't. So we use compgen only when _filedir is not provided.
+  _filedir 2> /dev/null || COMPREPLY=( $( compgen -f ) )
+}
+
 _clang()
 {
-  local cur prev words cword arg flags
-  _init_completion -n : || return
+  local cur prev words cword arg flags w1 w2
+  # If latest bash-completion is not supported just initialize COMPREPLY and
+  # initialize variables by setting manualy.
+  _init_completion -n 2> /dev/null
+  if [[ "$?" != 0 ]]; then
+    COMPREPLY=()
+    cword=$COMP_CWORD
+    cur="${COMP_WORDS[$cword]}"
+  fi
 
   # bash always separates '=' as a token even if there's no space before/after '='.
   # On the other hand, '=' is just a regular character for clang options that
   # contain '='. For example, "-stdlib=" is defined as is, instead of "-stdlib" and "=".
   # So, we need to partially undo bash tokenization here for integrity.
-  local w1="${COMP_WORDS[$cword - 1]}"
-  local w2="${COMP_WORDS[$cword - 2]}"
+  w1="${COMP_WORDS[$cword - 1]}"
+  if [[ $cword > 1 ]]; then
+    w2="${COMP_WORDS[$cword - 2]}"
+  fi
   if [[ "$cur" == -* ]]; then
     # -foo<tab>
     arg="$cur"
   elif [[ "$w1" == -*  && "$cur" == '=' ]]; then
     # -foo=<tab>
     arg="$w1=,"
   elif [[ "$w1" == -* ]]; then
     # -foo <tab> or -foo bar<tab>
     arg="$w1,$cur"
   elif [[ "$w2" == -* && "$w1" == '=' ]]; then
     # -foo=bar<tab>
     arg="$w2=,$cur"
   fi
 
   flags=$( "${COMP_WORDS[0]}" --autocomplete="$arg" 2>/dev/null )
   # If clang is old that it does not support --autocomplete,
   # fall back to the filename completion.
   if [[ "$?" != 0 ]]; then
-    _filedir
+    _clang_filedir
     return
   fi
 
   if [[ "$cur" == '=' ]]; then
     COMPREPLY=( $( compgen -W "$flags" -- "") )
   elif [[ "$flags" == "" || "$arg" == "" ]]; then
-    _filedir
+    _clang_filedir
   else
     # Bash automatically appends a space after '=' by default.
     # Disable it so that it works nicely for options in the form of -foo=bar.
-    [[ "${flags: -1}" == '=' ]] && compopt -o nospace
+    [[ "${flags: -1}" == '=' ]] && compopt -o nospace 2> /dev/null
     COMPREPLY=( $( compgen -W "$flags" -- "$cur" ) )
   fi
 }
 complete -F _clang clang