tools: Add a bash completion script for the configure tool

tools/configure_completion.bash

@@ -0,0 +1,82 @@
+#!/usr/bin/env bash
+# tools/configure_completion.bash
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements.  See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership.  The
+# ASF licenses this file to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance with the
+# License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+
+function _nuttx_configure_completion
+{
+  local colon_idx=2
+  local num_options=0
+
+  # Skip ./tools/configure.sh script options.
+  while [[ "${#COMP_WORDS[@]}" != "${colon_idx}" ]] && [[ "${COMP_WORDS[$((colon_idx - 1))]}" == '-'* ]]
+  do
+    # If "-a" is among the provided arguments, consider the apps directory.
+    if [ "${COMP_WORDS[$((colon_idx - 1))]}" == "-a" ]; then
+      colon_idx=$((colon_idx + 2))
+      num_options=$((num_options + 2))
+    else
+      colon_idx=$((colon_idx + 1))
+      num_options=$((num_options + 1))
+    fi
+  done
+
+  # When the command line is complete, COMP_WORDS array will have 5 elements
+  # plus the options.
+  # The script may return when this state is reached.
+  if [ "${#COMP_WORDS[@]}" == $((5 + num_options)) ]; then
+    return
+  fi
+
+  # If the last provided argument is "-a", do not execute autocompletion
+  # algorithm.
+  if [ "${COMP_WORDS[-2]}" == "-a" ]; then
+    return
+  fi
+
+  local search_dir=""
+  local search_pattern=""
+  local reply_suffix=""
+
+  if [ "${COMP_WORDS[${colon_idx}]}" == ':' ]; then
+    local board_name=${COMP_WORDS[$((colon_idx - 1))]}
+    local config_name=${COMP_WORDS[$((colon_idx + 1))]}
+
+    search_dir="boards/*/*/${board_name}/configs/"
+    search_pattern="${config_name}"
+    reply_suffix=" "
+  else
+    search_dir="boards/*/*/"
+    search_pattern="${COMP_WORDS[$((1 + num_options))]}"
+    reply_suffix=":"
+  fi
+
+  local wordlist
+  local suggestions
+  wordlist=$(find ${search_dir} -maxdepth 1 -mindepth 1 -type d -exec basename {} \;) 2>/dev/null
+  suggestions=($(compgen -W "${wordlist}" -- "${search_pattern}"))
+
+  if [ "${#suggestions[@]}" == "1" ]; then
+    # If there's only one match, complete with the appropriate reply suffix.
+    COMPREPLY=("${suggestions[0]}${reply_suffix}")
+  else
+    # More than one suggestion resolved, respond with the suggestions intact.
+    COMPREPLY=("${suggestions[@]}")
+  fi
+}
+
+complete -o bashdefault -o default -o nospace -F _nuttx_configure_completion ./tools/configure.sh