root/ws.c

DEFINITIONS

1. parse_whitespace_rule
2. setup_whitespace_attr_check
3. whitespace_rule
4. whitespace_error_string
5. ws_check_emit_1
6. ws_check_emit
7. ws_check
8. ws_blank_line
9. ws_fix_copy

/*
 * Whitespace rules
 *
 * Copyright (c) 2007 Junio C Hamano
 */

#include "cache.h"
#include "attr.h"

static struct whitespace_rule {
        const char *rule_name;
        unsigned rule_bits;
        unsigned loosens_error:1,
                exclude_default:1;
} whitespace_rule_names[] = {
        { "trailing-space", WS_TRAILING_SPACE, 0 },
        { "space-before-tab", WS_SPACE_BEFORE_TAB, 0 },
        { "indent-with-non-tab", WS_INDENT_WITH_NON_TAB, 0 },
        { "cr-at-eol", WS_CR_AT_EOL, 1 },
        { "blank-at-eol", WS_BLANK_AT_EOL, 0 },
        { "blank-at-eof", WS_BLANK_AT_EOF, 0 },
        { "tab-in-indent", WS_TAB_IN_INDENT, 0, 1 },
};

unsigned parse_whitespace_rule(const char *string)
{
        unsigned rule = WS_DEFAULT_RULE;

        while (string) {
                int i;
                size_t len;
                const char *ep;
                int negated = 0;

                string = string + strspn(string, ", \t\n\r");
                ep = strchrnul(string, ',');
                len = ep - string;

                if (*string == '-') {
                        negated = 1;
                        string++;
                        len--;
                }
                if (!len)
                        break;
                for (i = 0; i < ARRAY_SIZE(whitespace_rule_names); i++) {
                        if (strncmp(whitespace_rule_names[i].rule_name,
                                    string, len))
                                continue;
                        if (negated)
                                rule &= ~whitespace_rule_names[i].rule_bits;
                        else
                                rule |= whitespace_rule_names[i].rule_bits;
                        break;
                }
                if (strncmp(string, "tabwidth=", 9) == 0) {
                        unsigned tabwidth = atoi(string + 9);
                        if (0 < tabwidth && tabwidth < 0100) {
                                rule &= ~WS_TAB_WIDTH_MASK;
                                rule |= tabwidth;
                        }
                        else
                                warning("tabwidth %.*s out of range",
                                        (int)(len - 9), string + 9);
                }
                string = ep;
        }

        if (rule & WS_TAB_IN_INDENT && rule & WS_INDENT_WITH_NON_TAB)
                die("cannot enforce both tab-in-indent and indent-with-non-tab");
        return rule;
}

static void setup_whitespace_attr_check(struct git_attr_check *check)
{
        static struct git_attr *attr_whitespace;

        if (!attr_whitespace)
                attr_whitespace = git_attr("whitespace");
        check[0].attr = attr_whitespace;
}

unsigned whitespace_rule(const char *pathname)
{
        struct git_attr_check attr_whitespace_rule;

        setup_whitespace_attr_check(&attr_whitespace_rule);
        if (!git_check_attr(pathname, 1, &attr_whitespace_rule)) {
                const char *value;

                value = attr_whitespace_rule.value;
                if (ATTR_TRUE(value)) {
                        /* true (whitespace) */
                        unsigned all_rule = ws_tab_width(whitespace_rule_cfg);
                        int i;
                        for (i = 0; i < ARRAY_SIZE(whitespace_rule_names); i++)
                                if (!whitespace_rule_names[i].loosens_error &&
                                    !whitespace_rule_names[i].exclude_default)
                                        all_rule |= whitespace_rule_names[i].rule_bits;
                        return all_rule;
                } else if (ATTR_FALSE(value)) {
                        /* false (-whitespace) */
                        return ws_tab_width(whitespace_rule_cfg);
                } else if (ATTR_UNSET(value)) {
                        /* reset to default (!whitespace) */
                        return whitespace_rule_cfg;
                } else {
                        /* string */
                        return parse_whitespace_rule(value);
                }
        } else {
                return whitespace_rule_cfg;
        }
}

/* The returned string should be freed by the caller. */
char *whitespace_error_string(unsigned ws)
{
        struct strbuf err = STRBUF_INIT;
        if ((ws & WS_TRAILING_SPACE) == WS_TRAILING_SPACE)
                strbuf_addstr(&err, "trailing whitespace");
        else {
                if (ws & WS_BLANK_AT_EOL)
                        strbuf_addstr(&err, "trailing whitespace");
                if (ws & WS_BLANK_AT_EOF) {
                        if (err.len)
                                strbuf_addstr(&err, ", ");
                        strbuf_addstr(&err, "new blank line at EOF");
                }
        }
        if (ws & WS_SPACE_BEFORE_TAB) {
                if (err.len)
                        strbuf_addstr(&err, ", ");
                strbuf_addstr(&err, "space before tab in indent");
        }
        if (ws & WS_INDENT_WITH_NON_TAB) {
                if (err.len)
                        strbuf_addstr(&err, ", ");
                strbuf_addstr(&err, "indent with spaces");
        }
        if (ws & WS_TAB_IN_INDENT) {
                if (err.len)
                        strbuf_addstr(&err, ", ");
                strbuf_addstr(&err, "tab in indent");
        }
        return strbuf_detach(&err, NULL);
}

/* If stream is non-NULL, emits the line after checking. */
static unsigned ws_check_emit_1(const char *line, int len, unsigned ws_rule,
                                FILE *stream, const char *set,
                                const char *reset, const char *ws)
{
        unsigned result = 0;
        int written = 0;
        int trailing_whitespace = -1;
        int trailing_newline = 0;
        int trailing_carriage_return = 0;
        int i;

        /* Logic is simpler if we temporarily ignore the trailing newline. */
        if (len > 0 && line[len - 1] == '\n') {
                trailing_newline = 1;
                len--;
        }
        if ((ws_rule & WS_CR_AT_EOL) &&
            len > 0 && line[len - 1] == '\r') {
                trailing_carriage_return = 1;
                len--;
        }

        /* Check for trailing whitespace. */
        if (ws_rule & WS_BLANK_AT_EOL) {
                for (i = len - 1; i >= 0; i--) {
                        if (isspace(line[i])) {
                                trailing_whitespace = i;
                                result |= WS_BLANK_AT_EOL;
                        }
                        else
                                break;
                }
        }

        if (trailing_whitespace == -1)
                trailing_whitespace = len;

        /* Check indentation */
        for (i = 0; i < trailing_whitespace; i++) {
                if (line[i] == ' ')
                        continue;
                if (line[i] != '\t')
                        break;
                if ((ws_rule & WS_SPACE_BEFORE_TAB) && written < i) {
                        result |= WS_SPACE_BEFORE_TAB;
                        if (stream) {
                                fputs(ws, stream);
                                fwrite(line + written, i - written, 1, stream);
                                fputs(reset, stream);
                                fwrite(line + i, 1, 1, stream);
                        }
                } else if (ws_rule & WS_TAB_IN_INDENT) {
                        result |= WS_TAB_IN_INDENT;
                        if (stream) {
                                fwrite(line + written, i - written, 1, stream);
                                fputs(ws, stream);
                                fwrite(line + i, 1, 1, stream);
                                fputs(reset, stream);
                        }
                } else if (stream) {
                        fwrite(line + written, i - written + 1, 1, stream);
                }
                written = i + 1;
        }

        /* Check for indent using non-tab. */
        if ((ws_rule & WS_INDENT_WITH_NON_TAB) && i - written >= ws_tab_width(ws_rule)) {
                result |= WS_INDENT_WITH_NON_TAB;
                if (stream) {
                        fputs(ws, stream);
                        fwrite(line + written, i - written, 1, stream);
                        fputs(reset, stream);
                }
                written = i;
        }

        if (stream) {
                /*
                 * Now the rest of the line starts at "written".
                 * The non-highlighted part ends at "trailing_whitespace".
                 */

                /* Emit non-highlighted (middle) segment. */
                if (trailing_whitespace - written > 0) {
                        fputs(set, stream);
                        fwrite(line + written,
                            trailing_whitespace - written, 1, stream);
                        fputs(reset, stream);
                }

                /* Highlight errors in trailing whitespace. */
                if (trailing_whitespace != len) {
                        fputs(ws, stream);
                        fwrite(line + trailing_whitespace,
                            len - trailing_whitespace, 1, stream);
                        fputs(reset, stream);
                }
                if (trailing_carriage_return)
                        fputc('\r', stream);
                if (trailing_newline)
                        fputc('\n', stream);
        }
        return result;
}

void ws_check_emit(const char *line, int len, unsigned ws_rule,
                   FILE *stream, const char *set,
                   const char *reset, const char *ws)
{
        (void)ws_check_emit_1(line, len, ws_rule, stream, set, reset, ws);
}

unsigned ws_check(const char *line, int len, unsigned ws_rule)
{
        return ws_check_emit_1(line, len, ws_rule, NULL, NULL, NULL, NULL);
}

int ws_blank_line(const char *line, int len, unsigned ws_rule)
{
        /*
         * We _might_ want to treat CR differently from other
         * whitespace characters when ws_rule has WS_CR_AT_EOL, but
         * for now we just use this stupid definition.
         */
        while (len-- > 0) {
                if (!isspace(*line))
                        return 0;
                line++;
        }
        return 1;
}

/* Copy the line onto the end of the strbuf while fixing whitespaces */
void ws_fix_copy(struct strbuf *dst, const char *src, int len, unsigned ws_rule, int *error_count)
{
        /*
         * len is number of bytes to be copied from src, starting
         * at src.  Typically src[len-1] is '\n', unless this is
         * the incomplete last line.
         */
        int i;
        int add_nl_to_tail = 0;
        int add_cr_to_tail = 0;
        int fixed = 0;
        int last_tab_in_indent = -1;
        int last_space_in_indent = -1;
        int need_fix_leading_space = 0;

        /*
         * Strip trailing whitespace
         */
        if (ws_rule & WS_BLANK_AT_EOL) {
                if (0 < len && src[len - 1] == '\n') {
                        add_nl_to_tail = 1;
                        len--;
                        if (0 < len && src[len - 1] == '\r') {
                                add_cr_to_tail = !!(ws_rule & WS_CR_AT_EOL);
                                len--;
                        }
                }
                if (0 < len && isspace(src[len - 1])) {
                        while (0 < len && isspace(src[len-1]))
                                len--;
                        fixed = 1;
                }
        }

        /*
         * Check leading whitespaces (indent)
         */
        for (i = 0; i < len; i++) {
                char ch = src[i];
                if (ch == '\t') {
                        last_tab_in_indent = i;
                        if ((ws_rule & WS_SPACE_BEFORE_TAB) &&
                            0 <= last_space_in_indent)
                            need_fix_leading_space = 1;
                } else if (ch == ' ') {
                        last_space_in_indent = i;
                        if ((ws_rule & WS_INDENT_WITH_NON_TAB) &&
                            ws_tab_width(ws_rule) <= i - last_tab_in_indent)
                                need_fix_leading_space = 1;
                } else
                        break;
        }

        if (need_fix_leading_space) {
                /* Process indent ourselves */
                int consecutive_spaces = 0;
                int last = last_tab_in_indent + 1;

                if (ws_rule & WS_INDENT_WITH_NON_TAB) {
                        /* have "last" point at one past the indent */
                        if (last_tab_in_indent < last_space_in_indent)
                                last = last_space_in_indent + 1;
                        else
                                last = last_tab_in_indent + 1;
                }

                /*
                 * between src[0..last-1], strip the funny spaces,
                 * updating them to tab as needed.
                 */
                for (i = 0; i < last; i++) {
                        char ch = src[i];
                        if (ch != ' ') {
                                consecutive_spaces = 0;
                                strbuf_addch(dst, ch);
                        } else {
                                consecutive_spaces++;
                                if (consecutive_spaces == ws_tab_width(ws_rule)) {
                                        strbuf_addch(dst, '\t');
                                        consecutive_spaces = 0;
                                }
                        }
                }
                while (0 < consecutive_spaces--)
                        strbuf_addch(dst, ' ');
                len -= last;
                src += last;
                fixed = 1;
        } else if ((ws_rule & WS_TAB_IN_INDENT) && last_tab_in_indent >= 0) {
                /* Expand tabs into spaces */
                int start = dst->len;
                int last = last_tab_in_indent + 1;
                for (i = 0; i < last; i++) {
                        if (src[i] == '\t')
                                do {
                                        strbuf_addch(dst, ' ');
                                } while ((dst->len - start) % ws_tab_width(ws_rule));
                        else
                                strbuf_addch(dst, src[i]);
                }
                len -= last;
                src += last;
                fixed = 1;
        }

        strbuf_add(dst, src, len);
        if (add_cr_to_tail)
                strbuf_addch(dst, '\r');
        if (add_nl_to_tail)
                strbuf_addch(dst, '\n');
        if (fixed && error_count)
                (*error_count)++;
}