xref: /src/usr.bin/indent/io.c

/*	$NetBSD: io.c,v 1.174 2023/05/16 11:32:01 rillig Exp $	*/

/*-
 * SPDX-License-Identifier: BSD-4-Clause
 *
 * Copyright (c) 1985 Sun Microsystems, Inc.
 * Copyright (c) 1980, 1993
 *	The Regents of the University of California.  All rights reserved.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__RCSID("$NetBSD: io.c,v 1.174 2023/05/16 11:32:01 rillig Exp $");

#include <stdio.h>
#include <string.h>

#include "indent.h"

/*
 * The current line, ready to be split into tokens, terminated with '\n'. The
 * current read position is inp.s, and the invariant inp.s < inp.e holds.
 */
static struct buffer inp;
static struct buffer indent_off_text;

static int paren_indent;


const char *
inp_p(void)
{
    return inp.st;
}

const char *
inp_line_start(void)
{
    return inp.mem;
}

char
inp_peek(void)
{
    return *inp.st;
}

char
inp_lookahead(size_t i)
{
    return inp.st[i];
}

void
inp_skip(void)
{
    inp.st++;
    if ((size_t)(inp.st - inp.mem) >= inp.len)
	inp_read_line();
}

char
inp_next(void)
{
    char ch = inp_peek();
    inp_skip();
    return ch;
}

static void
inp_read_next_line(FILE *f)
{
    inp.st = inp.mem;
    inp.len = 0;

    for (;;) {
	int ch = getc(f);
	if (ch == EOF) {
	    if (indent_enabled == indent_on) {
		buf_add_char(&inp, ' ');
		buf_add_char(&inp, '\n');
	    }
	    had_eof = true;
	    break;
	}

	if (ch != '\0')
	    buf_add_char(&inp, (char)ch);
	if (ch == '\n')
	    break;
    }
}

static void
output_char(char ch)
{
    fputc(ch, output);
    debug_vis_range("output_char '", &ch, 1, "'\n");
}

static void
output_range(const char *s, size_t len)
{
    fwrite(s, 1, len, output);
    debug_vis_range("output_range \"", s, len, "\"\n");
}

static int
output_indent(int old_ind, int new_ind)
{
    int ind = old_ind;

    if (opt.use_tabs) {
	int tabsize = opt.tabsize;
	int n = new_ind / tabsize - ind / tabsize;
	if (n > 0)
	    ind -= ind % tabsize;
	for (int i = 0; i < n; i++) {
	    fputc('\t', output);
	    ind += tabsize;
	}
    }

    for (; ind < new_ind; ind++)
	fputc(' ', output);

    debug_println("output_indent %d", ind);
    return ind;
}

static int
output_line_label(void)
{
    int ind;

    while (lab.len > 0 && ch_isblank(lab.mem[lab.len - 1]))
	lab.len--;

    ind = output_indent(0, compute_label_indent());
    output_range(lab.st, lab.len);
    ind = ind_add(ind, lab.st, lab.len);

    ps.is_case_label = false;
    return ind;
}

static int
output_line_code(int ind)
{

    int target_ind = compute_code_indent();
    for (int i = 0; i < ps.nparen; i++) {
	int paren_ind = ps.paren[i].indent;
	if (paren_ind >= 0) {
	    ps.paren[i].indent = (short)(-1 - (paren_ind + target_ind));
	    debug_println(
		"setting paren_indents[%d] from %d to %d for column %d",
		i, paren_ind, ps.paren[i].indent, target_ind + 1);
	}
    }

    ind = output_indent(ind, target_ind);
    output_range(code.st, code.len);
    return ind_add(ind, code.st, code.len);
}

static void
output_line_comment(int ind)
{
    int target_ind = ps.com_ind;
    const char *p = com.st;

    target_ind += ps.comment_delta;

    /* consider original indentation in case this is a box comment */
    for (; *p == '\t'; p++)
	target_ind += opt.tabsize;

    for (; target_ind < 0; p++) {
	if (*p == ' ')
	    target_ind++;
	else if (*p == '\t')
	    target_ind = next_tab(target_ind);
	else {
	    target_ind = 0;
	    break;
	}
    }

    /* if comment can't fit on this line, put it on the next line */
    if (ind > target_ind) {
	output_char('\n');
	ind = 0;
    }

    while (com.mem + com.len > p && ch_isspace(com.mem[com.len - 1]))
	com.len--;

    (void)output_indent(ind, target_ind);
    output_range(p, com.len - (size_t)(p - com.mem));

    ps.comment_delta = ps.n_comment_delta;
}

/*
 * Write a line of formatted source to the output file. The line consists of
 * the label, the code and the comment.
 *
 * Comments are written directly, bypassing this function.
 */
void
output_line(void)
{
    debug_printf("%s", __func__);
    debug_buffers();
    debug_println("");

    ps.is_function_definition = false;

    if (ps.blank_line_after_decl && ps.declaration == decl_no) {
	ps.blank_line_after_decl = false;
	if (lab.len > 0 || code.len > 0 || com.len > 0)
	    output_char('\n');
    }

    if (indent_enabled == indent_on) {
	if (ps.ind_level == 0)
	    ps.in_stmt_cont = false;	/* this is a class A kludge */

	if (opt.blank_line_after_decl && ps.declaration == decl_end
		&& ps.tos > 1) {
	    ps.declaration = decl_no;
	    ps.blank_line_after_decl = true;
	}

	int ind = 0;
	if (lab.len > 0)
	    ind = output_line_label();
	if (code.len > 0)
	    ind = output_line_code(ind);
	if (com.len > 0)
	    output_line_comment(ind);

	output_char('\n');
    }

    if (indent_enabled == indent_last_off_line) {
	indent_enabled = indent_on;
	output_range(indent_off_text.st, indent_off_text.len);
	indent_off_text.len = 0;
    }

    ps.decl_on_line = ps.in_decl;	/* for proper comment indentation */
    ps.in_stmt_cont = ps.in_stmt_or_decl && !ps.in_decl;
    ps.decl_indent_done = false;
    if (ps.extra_expr_indent == eei_last)
	ps.extra_expr_indent = eei_no;

    lab.len = 0;
    code.len = 0;
    com.len = 0;

    ps.ind_level = ps.ind_level_follow;
    ps.line_start_nparen = ps.nparen;

    if (ps.nparen > 0) {
	/* TODO: explain what negative indentation means */
	paren_indent = -1 - ps.paren[ps.nparen - 1].indent;
	debug_println("paren_indent is now %d", paren_indent);
    }

    ps.want_blank = false;
}

static int
compute_code_indent_lineup(int base_ind)
{
    int ind = paren_indent;
    int overflow = ind_add(ind, code.st, code.len) - opt.max_line_length;
    if (overflow < 0)
	return ind;

    if (ind_add(base_ind, code.st, code.len) < opt.max_line_length) {
	ind -= overflow + 2;
	if (ind > base_ind)
	    return ind;
	return base_ind;
    }

    return ind;
}

int
compute_code_indent(void)
{
    int base_ind = ps.ind_level * opt.indent_size;

    if (ps.line_start_nparen == 0) {
	if (ps.in_stmt_cont && ps.in_enum != in_enum_brace)
	    return base_ind + opt.continuation_indent;
	return base_ind;
    }

    if (opt.lineup_to_parens) {
	if (opt.lineup_to_parens_always)
	    return paren_indent;
	return compute_code_indent_lineup(base_ind);
    }

    if (ps.extra_expr_indent != eei_no)
	return base_ind + 2 * opt.continuation_indent;

    if (2 * opt.continuation_indent == opt.indent_size)
	return base_ind + opt.continuation_indent;
    else
	return base_ind + opt.continuation_indent * ps.line_start_nparen;
}

int
compute_label_indent(void)
{
    if (ps.is_case_label)
	return (int)(case_ind * (float)opt.indent_size);
    if (lab.st[0] == '#')
	return 0;
    return opt.indent_size * (ps.ind_level - 2);
}

void
inp_read_line(void)
{
    if (indent_enabled == indent_on)
	indent_off_text.len = 0;
    buf_add_chars(&indent_off_text, inp.mem, inp.len);
    inp_read_next_line(input);
}

void
clear_indent_off_text(void)
{
    indent_off_text.len = 0;
}