refactor(_comp_get_first_arg): return exit status

The current interface does not distinguish the case where no argument
is found and the case where the first argument is an empty string.
This patch returns whether the first argument is found through the
exit status.  This also modifies the callers so that they use the exit
status to check if the first argument is specified.

Author: akinomyoga

bash_completion

@@ -2137,6 +2137,7 @@ _comp_realcommand()
 
 # This function returns the first argument, excluding options
 # @var[out] ret First argument if any, or otherwise an empty string
+# @return True (0) if any argument is found, False (> 0) otherwise.
 # @since 2.12
 _comp_get_first_arg()
 {
@@ -2146,12 +2147,13 @@ _comp_get_first_arg()
     for ((i = 1; i < cword; i++)); do
         if [[ ${words[i]} != -?* ]]; then
             ret=${words[i]}
-            break
+            return 0
         elif [[ ${words[i]} == -- ]]; then
-            ((i + 1 < cword)) && ret=${words[i + 1]}
+            ((i + 1 < cword)) && ret=${words[i + 1]} && return 0
             break
         fi
     done
+    return 1
 }
 
 # This function counts the number of args, excluding options

completions/cryptsetup

@@ -35,19 +35,8 @@ _comp_cmd_cryptsetup()
     [[ $was_split ]] && return
 
     local ret
-    _comp_get_first_arg
-    local arg=$ret
-    if [[ ! $arg ]]; then
-        if [[ $cur == -* ]]; then
-            _comp_compgen_help
-            [[ ${COMPREPLY-} == *= ]] && compopt -o nospace
-        else
-            _comp_compgen -- -W 'open close resize status benchmark repair
-                erase luksFormat luksAddKey luksRemoveKey luksChangeKey
-                luksKillSlot luksUUID isLuks luksDump tcryptDump luksSuspend
-                luksResume luksHeaderBackup luksHeaderRestore'
-        fi
-    else
+    if _comp_get_first_arg; then
+        local arg=$ret
         _comp_count_args "" "-${noargopts}[chslSbopitTdM]"
         local args=$ret
         case $arg in
@@ -97,6 +86,16 @@ _comp_cmd_cryptsetup()
                 esac
                 ;;
         esac
+    else
+        if [[ $cur == -* ]]; then
+            _comp_compgen_help
+            [[ ${COMPREPLY-} == *= ]] && compopt -o nospace
+        else
+            _comp_compgen -- -W 'open close resize status benchmark repair
+                erase luksFormat luksAddKey luksRemoveKey luksChangeKey
+                luksKillSlot luksUUID isLuks luksDump tcryptDump luksSuspend
+                luksResume luksHeaderBackup luksHeaderRestore'
+        fi
     fi
 
 } &&

completions/hcitool

@@ -46,15 +46,7 @@ _comp_cmd_hcitool()
     [[ $was_split ]] && return
 
     local ret
-    _comp_get_first_arg
-    if [[ ! $ret ]]; then
-        if [[ $cur == -* ]]; then
-            _comp_compgen_help
-        else
-            _comp_compgen -- -W 'dev inq scan name info spinq epinq cmd con cc
-                dc sr cpt rssi lq tpl afh lst auth enc key clkoff clock'
-        fi
-    else
+    if _comp_get_first_arg; then
         case $ret in
             name | info | dc | rssi | lq | afh | auth | key | clkoff | lst)
                 _comp_count_args
@@ -97,6 +89,13 @@ _comp_cmd_hcitool()
                 fi
                 ;;
         esac
+    else
+        if [[ $cur == -* ]]; then
+            _comp_compgen_help
+        else
+            _comp_compgen -- -W 'dev inq scan name info spinq epinq cmd con cc
+                dc sr cpt rssi lq tpl afh lst auth enc key clkoff clock'
+        fi
     fi
 } &&
     complete -F _comp_cmd_hcitool hcitool
@@ -116,15 +115,7 @@ _comp_cmd_sdptool()
     [[ $was_split ]] && return
 
     local ret
-    _comp_get_first_arg
-    if [[ ! $ret ]]; then
-        if [[ $cur == -* ]]; then
-            _comp_compgen_help
-        else
-            _comp_compgen -- -W 'search browse records add del get setattr
-                setseq'
-        fi
-    else
+    if _comp_get_first_arg; then
         case $ret in
             search)
                 if [[ $cur == -* ]]; then
@@ -153,6 +144,13 @@ _comp_cmd_sdptool()
                 fi
                 ;;
         esac
+    else
+        if [[ $cur == -* ]]; then
+            _comp_compgen_help
+        else
+            _comp_compgen -- -W 'search browse records add del get setattr
+                setseq'
+        fi
     fi
 } &&
     complete -F _comp_cmd_sdptool sdptool
@@ -198,15 +196,8 @@ _comp_cmd_rfcomm()
     esac
 
     local ret
-    _comp_get_first_arg
-    local arg=$ret
-    if [[ ! $arg ]]; then
-        if [[ $cur == -* ]]; then
-            _comp_compgen_help
-        else
-            _comp_compgen -- -W 'show connect listen watch bind release'
-        fi
-    else
+    if _comp_get_first_arg; then
+        local arg=$ret
         _comp_count_args
         local args=$ret
         if ((args == 2)); then
@@ -220,6 +211,12 @@ _comp_cmd_rfcomm()
                     ;;
             esac
         fi
+    else
+        if [[ $cur == -* ]]; then
+            _comp_compgen_help
+        else
+            _comp_compgen -- -W 'show connect listen watch bind release'
+        fi
     fi
 } &&
     complete -F _comp_cmd_rfcomm rfcomm
@@ -238,14 +235,7 @@ _comp_cmd_ciptool()
     esac
 
     local ret
-    _comp_get_first_arg
-    if [[ ! $ret ]]; then
-        if [[ $cur == -* ]]; then
-            _comp_compgen_help
-        else
-            _comp_compgen -- -W 'show search connect release loopback'
-        fi
-    else
+    if _comp_get_first_arg; then
         case $ret in
             connect | release | loopback)
                 local ret
@@ -255,6 +245,12 @@ _comp_cmd_ciptool()
                 fi
                 ;;
         esac
+    else
+        if [[ $cur == -* ]]; then
+            _comp_compgen_help
+        else
+            _comp_compgen -- -W 'show search connect release loopback'
+        fi
     fi
 } &&
     complete -F _comp_cmd_ciptool ciptool
@@ -294,18 +290,7 @@ _comp_cmd_hciconfig()
     _comp_initialize -- "$@" || return
 
     local ret
-    _comp_get_first_arg
-    if [[ ! $ret ]]; then
-        if [[ $cur == -* ]]; then
-            _comp_compgen -- -W '--help --all'
-        else
-            _comp_compgen -- -W 'up down reset rstat auth noauth encrypt
-                noencrypt secmgr nosecmgr piscan noscan iscan pscan ptype name
-                class voice iac inqmode inqdata inqtype inqparams pageparms
-                pageto afhmode aclmtu scomtu putkey delkey commands features
-                version revision lm'
-        fi
-    else
+    if _comp_get_first_arg; then
         case $ret in
             putkey | delkey)
                 _comp_count_args
@@ -326,6 +311,16 @@ _comp_cmd_hciconfig()
                 fi
                 ;;
         esac
+    else
+        if [[ $cur == -* ]]; then
+            _comp_compgen -- -W '--help --all'
+        else
+            _comp_compgen -- -W 'up down reset rstat auth noauth encrypt
+                noencrypt secmgr nosecmgr piscan noscan iscan pscan ptype name
+                class voice iac inqmode inqdata inqtype inqparams pageparms
+                pageto afhmode aclmtu scomtu putkey delkey commands features
+                version revision lm'
+        fi
     fi
 } &&
     complete -F _comp_cmd_hciconfig hciconfig