bpx.bash

#!/usr/bin/env bash
#
# bpx -- bash-pre-execution
# Copyright (C) 2015,2016,2017,2018ff. D630, GNU GPLv3
# <https://github.com/D630/bpx>
#
# Forked from Ryan Caloras (ryan@bashhub.com)
# <https://github.com/rcaloras/bash-preexec>

# -- FUNCTIONS.

## -- HOOKS.

function __bpx_hook_debug {
	set -- "$?";

	((${#debug_functions[@]})) ||
		return "$1";

	# Test, if *preread*, *preexec* and *postread* is hooking.
	# To avoid subshells, test also: 'BASHPID' -ne "$$"
	if
		[[ -v bpx_var[3] ]];
	then
		[[
			bpx_var[1] -eq 0 ||
			-v COMP_LINE ||
			-v READLINE_LINE ||
			-z "$rl0"
		]] &&
			return 0;
	else
		[[ -v COMP_LINE || -v READLINE_LINE ]] &&
			return 0;
	fi;

	case $BASH_COMMAND in
		(''|__bpx_hook_postread|*__bpx_hook_prompt|*__bpx_return)
			return 0;;
	esac;

	case ${FUNCNAME[1]} in
		(__bpx_hook_postread|*__bpx_hook_prompt|*__bpx_return)
			return 0;;
	esac;

	case ${FUNCNAME[2]} in
		(__bpx_hook_postread|*__bpx_hook_prompt|*__bpx_return)
			return 0;;
	esac;

	bpx_var[2]+=1;

	declare +x \
		__ \
		rl0;

	# TODO(D630): HISTCMD and parameter transformation of \! expands always to
	# one, when they are running in a trap:
	# h='\!';
	# h="${h@P}";
	[[ bpx_var[2] -eq 1 && -o history ]] &&
		histcmd=$(HISTTIMEFORMAT=%%; history 1) &&
			histcmd=${histcmd#*%};

	for __ in "${debug_functions[@]}"; do
		> /dev/null declare -F "$__" ||
			continue;

		\__bpx_return "$1";

		histcmd=$histcmd "$__" ||
			break;
	done;
};

function __bpx_hook_postread {
	set -- "$?" "$1";

	((${#postread_functions[@]})) ||
		return "$1";

	declare +x \
		__ \
		rl0;

	rl0=$2;

	((bpx_var[1] && ${#rl0})) ||
		return "$1";

	for __ in "${postread_functions[@]}"; do
		> /dev/null declare -F "$__" ||
			continue;

		\__bpx_return "$1";

		"$__" ||
			break;
	done 1>&2;

	return "$1";
};

function __bpx_hook_preexec {
	((${#preexec_functions[@]})) ||
		return 0;

	declare +x \
		READLINE_LINE \
		READLINE_POINT \
		__ \
		rl0;

	READLINE_LINE=;
	READLINE_POINT=;
	rl0=$1;

	for __ in "${preexec_functions[@]}"; do
		> /dev/null declare -F "$__" ||
			continue;

		\__bpx_return "${bpx_var[3]}";

		"$__" ||
			break;
	done 1>&2;
};

function __bpx_hook_preread {
	((${#preread_functions[@]})) ||
		return 0;

	declare +x \
		__ \
		rl0;

	rl0=$1;

	for __ in "${preread_functions[@]}"; do
		> /dev/null declare -F "$__" ||
			continue;

		\__bpx_return ${bpx_var[3]};

		"$__" ||
			break;
	done 1>&2;
};

function __bpx_hook_prompt {
	set -- "$?";

	((${#prompt_functions[@]})) ||
		return "$1";

	declare +x \
		__ \
		rl0;

	for __ in "${prompt_functions[@]}"; do
		> /dev/null declare -F "$__" ||
			continue;

		 \__bpx_return "$1";

		"$__" ||
			break;
	done;

	return "$1";
};

## -- MISC.

function __bpx_command_line case . in esac;

function __bpx_edit {
	command vim -f \
		'+set ft=sh' \
		"+call cursor(1,$READLINE_POINT+1)" \
		"${1?}" < /dev/tty > /dev/tty;
};

function __bpx_edit_and_execute_command {
	READLINE_LINE=$(
		unset -v f;
		f=${TMPDIR:-/tmp}/bash-bpx.$RANDOM;

		printf '%s\n' "$rl0" >| "$f";
		command chmod 600 -- "$f" > /dev/null 2>&1;
		\__bpx_edit "$f";

		if
			command cmp -s -- <(printf '%s\n' "$rl0") "$f";
		then
			printf '%s\n' "$rl0";
			command rm -- "$f" > /dev/null 2>&1;
			exit 1;
		else
			command cat -- "$f" 2>&1;
			command rm -- "$f" > /dev/null 2>&1;
			exit 0;
		fi;
	);
};

function __bpx_set_binds {
	bind -m emacs-standard '"\C-x\C-x1": "\C-x\C-x2\C-x\C-x6"';

	bind -m emacs-standard '"\C-x\C-x2": "\C-x\C-x3\C-x\C-x4\C-x\C-x5"';
	bind -m emacs-standard -x '"\C-x\C-x3": rl0=$READLINE_LINE';
	bind -m emacs-standard '"\C-x\C-x4": history-expand-line';
	bind -m emacs-standard -x '"\C-x\C-x5": \__bpx_read_line && {
			\__bpx_hook_preread "$rl0";
			\__bpx_hook_preexec "$rl0";
		};
	';

	bind -m emacs-standard '"\C-x\C-x6": "\C-x\C-x7"';

	bind -m emacs-standard '"\C-x\C-x7": "\C-x\C-x8\C-x\C-x9"';
	bind -m emacs-standard '"\C-x\C-x8": accept-line';
	bind -m emacs-standard -x '"\C-x\C-x9": \__bpx_hook_postread "$rl0"';
};

function __bpx_set_rl1 {
	mapfile -t -s 2 rl1 < <(
		declare -f __bpx_command_line 2> /dev/null;
	);

	((${#rl1[@]})) ||
		return 1;

	unset -v rl1[-1];
};

function __bpx_set_rl2 {
	((${#rl1[@]})) ||
		\__bpx_set_rl1 ||
			return 1;

	declare +x IFS;
	IFS=' ';
	read -r -a rl2 <<< "${rl1[@]}";
};

function __bpx_read_abort {
	bpx_var=1;
	bind -m emacs-standard '"\C-x\C-x8": abort';
};

function __bpx_read_accept {
	bpx_var=0;
	bind -m emacs-standard '"\C-x\C-x6": "\C-x\C-x7"';
	bind -m emacs-standard '"\C-x\C-x8": accept-line';
};

function __bpx_read_again {
	bpx_var=1;
	bind -m emacs-standard '"\C-x\C-x6": "\C-x\C-x1"';
};

function __bpx_read_line {
	bpx_var[bpx_var[1]=0,3]=$?;

	((bpx_var)) &&
		\__bpx_read_accept;

	((${#rl0})) ||
		return 1;

	# Test, if history expansion has been performed.
	[[ $rl0 != "$READLINE_LINE" && -o histexpand ]] &&
		READLINE_LINE=$rl0 &&
			return 1;

	#source <()
	#bash -n
	# TODO(D630): Works earlier than bash 5.0 without command substition.
	declare evaled;
	evaled=$(
		eval "
			function __bpx_command_line {
				$rl0
			};
		" 2> /dev/null &&
			declare -fp __bpx_command_line;
	) &&
		eval "$evaled" &&
			bpx_var[1]=1 &&
				rl1=() &&
					rl2=() &&
						return 0;

	if
		\__bpx_edit_and_execute_command;
	then
		\__bpx_read_again;
	else
		\__bpx_read_abort;
	fi;

	return 1;
};

function __bpx_return {
	return "$1";
};

# -- MAIN.

function __bpx_main {
	# internal integer indexed array variable *bpx_var*:
	# 0 is one when command line isn't valid
	# 1 is one when complete command line has been read
	# 2 number of *BASH_COMMAND* in a command line (*debug*)
	# 3 last status code
	#
	# Don't mess around with it.

	unset -v \
		bpx_var \
		histcmd \
		debug_functions \
		postread_functions \
		preexec_functions \
		preread_functions \
		prompt_functions \
		rl0 \
		rl1 \
		rl2;

	declare -g \
		histcmd \
		rl0;

	declare -g -a \
		debug_functions \
		postread_functions \
		preexec_functions \
		preread_functions \
		prompt_functions \
		rl1 \
		rl2;

	debug_functions=();
	postread_functions=();
	preexec_functions=();
	preread_functions=();
	prompt_functions=();

	declare -g -a -i bpx_var;
	bpx_var=(0 0 0);

	\__bpx_set_binds;
};

declare -fr \
	__bpx_edit_and_execute_command \
	__bpx_hook_debug \
	__bpx_hook_postread \
	__bpx_hook_preexec \
	__bpx_hook_preread \
	__bpx_hook_prompt \
	__bpx_main \
	__bpx_read_abort \
	__bpx_read_accept \
	__bpx_read_again \
	__bpx_read_line \
	__bpx_return \
	__bpx_set_binds \
	__bpx_set_rl1 \
	__bpx_set_rl2;

\__bpx_main;

# -- TEST CONFIGURATION

# . src/bpx/test.bash;

# vim: set ft=sh :