Merge branch 'tr/maint-cherry-pick-list' into maint

[tgit.git] / grep.c

#include "cache.h"
#include "grep.h"
#include "userdiff.h"
#include "xdiff-interface.h"

void append_header_grep_pattern(struct grep_opt *opt, enum grep_header_field field, const char *pat)
{
        struct grep_pat *p = xcalloc(1, sizeof(*p));
        p->pattern = pat;
        p->origin = "header";
        p->no = 0;
        p->token = GREP_PATTERN_HEAD;
        p->field = field;
        *opt->pattern_tail = p;
        opt->pattern_tail = &p->next;
        p->next = NULL;
}

void append_grep_pattern(struct grep_opt *opt, const char *pat,
                         const char *origin, int no, enum grep_pat_token t)
{
        struct grep_pat *p = xcalloc(1, sizeof(*p));
        p->pattern = pat;
        p->origin = origin;
        p->no = no;
        p->token = t;
        *opt->pattern_tail = p;
        opt->pattern_tail = &p->next;
        p->next = NULL;
}

struct grep_opt *grep_opt_dup(const struct grep_opt *opt)
{
        struct grep_pat *pat;
        struct grep_opt *ret = xmalloc(sizeof(struct grep_opt));
        *ret = *opt;

        ret->pattern_list = NULL;
        ret->pattern_tail = &ret->pattern_list;

        for(pat = opt->pattern_list; pat != NULL; pat = pat->next)
        {
                if(pat->token == GREP_PATTERN_HEAD)
                        append_header_grep_pattern(ret, pat->field,
                                                   pat->pattern);
                else
                        append_grep_pattern(ret, pat->pattern, pat->origin,
                                            pat->no, pat->token);
        }

        return ret;
}

static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
{
        int err;

        p->word_regexp = opt->word_regexp;
        p->ignore_case = opt->ignore_case;
        p->fixed = opt->fixed;

        if (p->fixed)
                return;

        err = regcomp(&p->regexp, p->pattern, opt->regflags);
        if (err) {
                char errbuf[1024];
                char where[1024];
                if (p->no)
                        sprintf(where, "In '%s' at %d, ",
                                p->origin, p->no);
                else if (p->origin)
                        sprintf(where, "%s, ", p->origin);
                else
                        where[0] = 0;
                regerror(err, &p->regexp, errbuf, 1024);
                regfree(&p->regexp);
                die("%s'%s': %s", where, p->pattern, errbuf);
        }
}

static struct grep_expr *compile_pattern_or(struct grep_pat **);
static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
{
        struct grep_pat *p;
        struct grep_expr *x;

        p = *list;
        if (!p)
                return NULL;
        switch (p->token) {
        case GREP_PATTERN: /* atom */
        case GREP_PATTERN_HEAD:
        case GREP_PATTERN_BODY:
                x = xcalloc(1, sizeof (struct grep_expr));
                x->node = GREP_NODE_ATOM;
                x->u.atom = p;
                *list = p->next;
                return x;
        case GREP_OPEN_PAREN:
                *list = p->next;
                x = compile_pattern_or(list);
                if (!*list || (*list)->token != GREP_CLOSE_PAREN)
                        die("unmatched parenthesis");
                *list = (*list)->next;
                return x;
        default:
                return NULL;
        }
}

static struct grep_expr *compile_pattern_not(struct grep_pat **list)
{
        struct grep_pat *p;
        struct grep_expr *x;

        p = *list;
        if (!p)
                return NULL;
        switch (p->token) {
        case GREP_NOT:
                if (!p->next)
                        die("--not not followed by pattern expression");
                *list = p->next;
                x = xcalloc(1, sizeof (struct grep_expr));
                x->node = GREP_NODE_NOT;
                x->u.unary = compile_pattern_not(list);
                if (!x->u.unary)
                        die("--not followed by non pattern expression");
                return x;
        default:
                return compile_pattern_atom(list);
        }
}

static struct grep_expr *compile_pattern_and(struct grep_pat **list)
{
        struct grep_pat *p;
        struct grep_expr *x, *y, *z;

        x = compile_pattern_not(list);
        p = *list;
        if (p && p->token == GREP_AND) {
                if (!p->next)
                        die("--and not followed by pattern expression");
                *list = p->next;
                y = compile_pattern_and(list);
                if (!y)
                        die("--and not followed by pattern expression");
                z = xcalloc(1, sizeof (struct grep_expr));
                z->node = GREP_NODE_AND;
                z->u.binary.left = x;
                z->u.binary.right = y;
                return z;
        }
        return x;
}

static struct grep_expr *compile_pattern_or(struct grep_pat **list)
{
        struct grep_pat *p;
        struct grep_expr *x, *y, *z;

        x = compile_pattern_and(list);
        p = *list;
        if (x && p && p->token != GREP_CLOSE_PAREN) {
                y = compile_pattern_or(list);
                if (!y)
                        die("not a pattern expression %s", p->pattern);
                z = xcalloc(1, sizeof (struct grep_expr));
                z->node = GREP_NODE_OR;
                z->u.binary.left = x;
                z->u.binary.right = y;
                return z;
        }
        return x;
}

static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
{
        return compile_pattern_or(list);
}

void compile_grep_patterns(struct grep_opt *opt)
{
        struct grep_pat *p;

        if (opt->all_match)
                opt->extended = 1;

        for (p = opt->pattern_list; p; p = p->next) {
                switch (p->token) {
                case GREP_PATTERN: /* atom */
                case GREP_PATTERN_HEAD:
                case GREP_PATTERN_BODY:
                        compile_regexp(p, opt);
                        break;
                default:
                        opt->extended = 1;
                        break;
                }
        }

        if (!opt->extended)
                return;

        /* Then bundle them up in an expression.
         * A classic recursive descent parser would do.
         */
        p = opt->pattern_list;
        if (p)
                opt->pattern_expression = compile_pattern_expr(&p);
        if (p)
                die("incomplete pattern expression: %s", p->pattern);
}

static void free_pattern_expr(struct grep_expr *x)
{
        switch (x->node) {
        case GREP_NODE_ATOM:
                break;
        case GREP_NODE_NOT:
                free_pattern_expr(x->u.unary);
                break;
        case GREP_NODE_AND:
        case GREP_NODE_OR:
                free_pattern_expr(x->u.binary.left);
                free_pattern_expr(x->u.binary.right);
                break;
        }
        free(x);
}

void free_grep_patterns(struct grep_opt *opt)
{
        struct grep_pat *p, *n;

        for (p = opt->pattern_list; p; p = n) {
                n = p->next;
                switch (p->token) {
                case GREP_PATTERN: /* atom */
                case GREP_PATTERN_HEAD:
                case GREP_PATTERN_BODY:
                        regfree(&p->regexp);
                        break;
                default:
                        break;
                }
                free(p);
        }

        if (!opt->extended)
                return;
        free_pattern_expr(opt->pattern_expression);
}

static char *end_of_line(char *cp, unsigned long *left)
{
        unsigned long l = *left;
        while (l && *cp != '\n') {
                l--;
                cp++;
        }
        *left = l;
        return cp;
}

static int word_char(char ch)
{
        return isalnum(ch) || ch == '_';
}

static void show_name(struct grep_opt *opt, const char *name)
{
        opt->output(opt, name, strlen(name));
        opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
}


static int fixmatch(const char *pattern, char *line, int ignore_case, regmatch_t *match)
{
        char *hit;
        if (ignore_case)
                hit = strcasestr(line, pattern);
        else
                hit = strstr(line, pattern);

        if (!hit) {
                match->rm_so = match->rm_eo = -1;
                return REG_NOMATCH;
        }
        else {
                match->rm_so = hit - line;
                match->rm_eo = match->rm_so + strlen(pattern);
                return 0;
        }
}

static int strip_timestamp(char *bol, char **eol_p)
{
        char *eol = *eol_p;
        int ch;

        while (bol < --eol) {
                if (*eol != '>')
                        continue;
                *eol_p = ++eol;
                ch = *eol;
                *eol = '\0';
                return ch;
        }
        return 0;
}

static struct {
        const char *field;
        size_t len;
} header_field[] = {
        { "author ", 7 },
        { "committer ", 10 },
};

static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
                             enum grep_context ctx,
                             regmatch_t *pmatch, int eflags)
{
        int hit = 0;
        int saved_ch = 0;
        const char *start = bol;

        if ((p->token != GREP_PATTERN) &&
            ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
                return 0;

        if (p->token == GREP_PATTERN_HEAD) {
                const char *field;
                size_t len;
                assert(p->field < ARRAY_SIZE(header_field));
                field = header_field[p->field].field;
                len = header_field[p->field].len;
                if (strncmp(bol, field, len))
                        return 0;
                bol += len;
                saved_ch = strip_timestamp(bol, &eol);
        }

 again:
        if (p->fixed)
                hit = !fixmatch(p->pattern, bol, p->ignore_case, pmatch);
        else
                hit = !regexec(&p->regexp, bol, 1, pmatch, eflags);

        if (hit && p->word_regexp) {
                if ((pmatch[0].rm_so < 0) ||
                    (eol - bol) < pmatch[0].rm_so ||
                    (pmatch[0].rm_eo < 0) ||
                    (eol - bol) < pmatch[0].rm_eo)
                        die("regexp returned nonsense");

                /* Match beginning must be either beginning of the
                 * line, or at word boundary (i.e. the last char must
                 * not be a word char).  Similarly, match end must be
                 * either end of the line, or at word boundary
                 * (i.e. the next char must not be a word char).
                 */
                if ( ((pmatch[0].rm_so == 0) ||
                      !word_char(bol[pmatch[0].rm_so-1])) &&
                     ((pmatch[0].rm_eo == (eol-bol)) ||
                      !word_char(bol[pmatch[0].rm_eo])) )
                        ;
                else
                        hit = 0;

                /* Words consist of at least one character. */
                if (pmatch->rm_so == pmatch->rm_eo)
                        hit = 0;

                if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
                        /* There could be more than one match on the
                         * line, and the first match might not be
                         * strict word match.  But later ones could be!
                         * Forward to the next possible start, i.e. the
                         * next position following a non-word char.
                         */
                        bol = pmatch[0].rm_so + bol + 1;
                        while (word_char(bol[-1]) && bol < eol)
                                bol++;
                        eflags |= REG_NOTBOL;
                        if (bol < eol)
                                goto again;
                }
        }
        if (p->token == GREP_PATTERN_HEAD && saved_ch)
                *eol = saved_ch;
        if (hit) {
                pmatch[0].rm_so += bol - start;
                pmatch[0].rm_eo += bol - start;
        }
        return hit;
}

static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
                           enum grep_context ctx, int collect_hits)
{
        int h = 0;
        regmatch_t match;

        if (!x)
                die("Not a valid grep expression");
        switch (x->node) {
        case GREP_NODE_ATOM:
                h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
                break;
        case GREP_NODE_NOT:
                h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
                break;
        case GREP_NODE_AND:
                if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
                        return 0;
                h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
                break;
        case GREP_NODE_OR:
                if (!collect_hits)
                        return (match_expr_eval(x->u.binary.left,
                                                bol, eol, ctx, 0) ||
                                match_expr_eval(x->u.binary.right,
                                                bol, eol, ctx, 0));
                h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
                x->u.binary.left->hit |= h;
                h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
                break;
        default:
                die("Unexpected node type (internal error) %d", x->node);
        }
        if (collect_hits)
                x->hit |= h;
        return h;
}

static int match_expr(struct grep_opt *opt, char *bol, char *eol,
                      enum grep_context ctx, int collect_hits)
{
        struct grep_expr *x = opt->pattern_expression;
        return match_expr_eval(x, bol, eol, ctx, collect_hits);
}

static int match_line(struct grep_opt *opt, char *bol, char *eol,
                      enum grep_context ctx, int collect_hits)
{
        struct grep_pat *p;
        regmatch_t match;

        if (opt->extended)
                return match_expr(opt, bol, eol, ctx, collect_hits);

        /* we do not call with collect_hits without being extended */
        for (p = opt->pattern_list; p; p = p->next) {
                if (match_one_pattern(p, bol, eol, ctx, &match, 0))
                        return 1;
        }
        return 0;
}

static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
                              enum grep_context ctx,
                              regmatch_t *pmatch, int eflags)
{
        regmatch_t match;

        if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
                return 0;
        if (match.rm_so < 0 || match.rm_eo < 0)
                return 0;
        if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
                if (match.rm_so > pmatch->rm_so)
                        return 1;
                if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
                        return 1;
        }
        pmatch->rm_so = match.rm_so;
        pmatch->rm_eo = match.rm_eo;
        return 1;
}

static int next_match(struct grep_opt *opt, char *bol, char *eol,
                      enum grep_context ctx, regmatch_t *pmatch, int eflags)
{
        struct grep_pat *p;
        int hit = 0;

        pmatch->rm_so = pmatch->rm_eo = -1;
        if (bol < eol) {
                for (p = opt->pattern_list; p; p = p->next) {
                        switch (p->token) {
                        case GREP_PATTERN: /* atom */
                        case GREP_PATTERN_HEAD:
                        case GREP_PATTERN_BODY:
                                hit |= match_next_pattern(p, bol, eol, ctx,
                                                          pmatch, eflags);
                                break;
                        default:
                                break;
                        }
                }
        }
        return hit;
}

static void show_line(struct grep_opt *opt, char *bol, char *eol,
                      const char *name, unsigned lno, char sign)
{
        int rest = eol - bol;
        char sign_str[1];

        sign_str[0] = sign;
        if (opt->pre_context || opt->post_context) {
                if (opt->last_shown == 0) {
                        if (opt->show_hunk_mark)
                                opt->output(opt, "--\n", 3);
                        else
                                opt->show_hunk_mark = 1;
                } else if (lno > opt->last_shown + 1)
                        opt->output(opt, "--\n", 3);
        }
        opt->last_shown = lno;

        if (opt->null_following_name)
                sign_str[0] = '\0';
        if (opt->pathname) {
                opt->output(opt, name, strlen(name));
                opt->output(opt, sign_str, 1);
        }
        if (opt->linenum) {
                char buf[32];
                snprintf(buf, sizeof(buf), "%d", lno);
                opt->output(opt, buf, strlen(buf));
                opt->output(opt, sign_str, 1);
        }
        if (opt->color) {
                regmatch_t match;
                enum grep_context ctx = GREP_CONTEXT_BODY;
                int ch = *eol;
                int eflags = 0;

                *eol = '\0';
                while (next_match(opt, bol, eol, ctx, &match, eflags)) {
                        if (match.rm_so == match.rm_eo)
                                break;

                        opt->output(opt, bol, match.rm_so);
                        opt->output(opt, opt->color_match,
                                    strlen(opt->color_match));
                        opt->output(opt, bol + match.rm_so,
                                    (int)(match.rm_eo - match.rm_so));
                        opt->output(opt, GIT_COLOR_RESET,
                                    strlen(GIT_COLOR_RESET));
                        bol += match.rm_eo;
                        rest -= match.rm_eo;
                        eflags = REG_NOTBOL;
                }
                *eol = ch;
        }
        opt->output(opt, bol, rest);
        opt->output(opt, "\n", 1);
}

static int match_funcname(struct grep_opt *opt, char *bol, char *eol)
{
        xdemitconf_t *xecfg = opt->priv;
        if (xecfg && xecfg->find_func) {
                char buf[1];
                return xecfg->find_func(bol, eol - bol, buf, 1,
                                        xecfg->find_func_priv) >= 0;
        }

        if (bol == eol)
                return 0;
        if (isalpha(*bol) || *bol == '_' || *bol == '$')
                return 1;
        return 0;
}

static void show_funcname_line(struct grep_opt *opt, const char *name,
                               char *buf, char *bol, unsigned lno)
{
        while (bol > buf) {
                char *eol = --bol;

                while (bol > buf && bol[-1] != '\n')
                        bol--;
                lno--;

                if (lno <= opt->last_shown)
                        break;

                if (match_funcname(opt, bol, eol)) {
                        show_line(opt, bol, eol, name, lno, '=');
                        break;
                }
        }
}

static void show_pre_context(struct grep_opt *opt, const char *name, char *buf,
                             char *bol, unsigned lno)
{
        unsigned cur = lno, from = 1, funcname_lno = 0;
        int funcname_needed = opt->funcname;

        if (opt->pre_context < lno)
                from = lno - opt->pre_context;
        if (from <= opt->last_shown)
                from = opt->last_shown + 1;

        /* Rewind. */
        while (bol > buf && cur > from) {
                char *eol = --bol;

                while (bol > buf && bol[-1] != '\n')
                        bol--;
                cur--;
                if (funcname_needed && match_funcname(opt, bol, eol)) {
                        funcname_lno = cur;
                        funcname_needed = 0;
                }
        }

        /* We need to look even further back to find a function signature. */
        if (opt->funcname && funcname_needed)
                show_funcname_line(opt, name, buf, bol, cur);

        /* Back forward. */
        while (cur < lno) {
                char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';

                while (*eol != '\n')
                        eol++;
                show_line(opt, bol, eol, name, cur, sign);
                bol = eol + 1;
                cur++;
        }
}

static int should_lookahead(struct grep_opt *opt)
{
        struct grep_pat *p;

        if (opt->extended)
                return 0; /* punt for too complex stuff */
        if (opt->invert)
                return 0;
        for (p = opt->pattern_list; p; p = p->next) {
                if (p->token != GREP_PATTERN)
                        return 0; /* punt for "header only" and stuff */
        }
        return 1;
}

static int look_ahead(struct grep_opt *opt,
                      unsigned long *left_p,
                      unsigned *lno_p,
                      char **bol_p)
{
        unsigned lno = *lno_p;
        char *bol = *bol_p;
        struct grep_pat *p;
        char *sp, *last_bol;
        regoff_t earliest = -1;

        for (p = opt->pattern_list; p; p = p->next) {
                int hit;
                regmatch_t m;

                if (p->fixed)
                        hit = !fixmatch(p->pattern, bol, p->ignore_case, &m);
                else {
#ifdef REG_STARTEND
                        m.rm_so = 0;
                        m.rm_eo = *left_p;
                        hit = !regexec(&p->regexp, bol, 1, &m, REG_STARTEND);
#else
                        hit = !regexec(&p->regexp, bol, 1, &m, 0);
#endif
                }
                if (!hit || m.rm_so < 0 || m.rm_eo < 0)
                        continue;
                if (earliest < 0 || m.rm_so < earliest)
                        earliest = m.rm_so;
        }

        if (earliest < 0) {
                *bol_p = bol + *left_p;
                *left_p = 0;
                return 1;
        }
        for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
                ; /* find the beginning of the line */
        last_bol = sp;

        for (sp = bol; sp < last_bol; sp++) {
                if (*sp == '\n')
                        lno++;
        }
        *left_p -= last_bol - bol;
        *bol_p = last_bol;
        *lno_p = lno;
        return 0;
}

int grep_threads_ok(const struct grep_opt *opt)
{
        /* If this condition is true, then we may use the attribute
         * machinery in grep_buffer_1. The attribute code is not
         * thread safe, so we disable the use of threads.
         */
        if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
            !opt->name_only)
                return 0;

        /* If we are showing hunk marks, we should not do it for the
         * first match. The synchronization problem we get for this
         * constraint is not yet solved, so we disable threading in
         * this case.
         */
        if (opt->pre_context || opt->post_context)
                return 0;

        return 1;
}

static void std_output(struct grep_opt *opt, const void *buf, size_t size)
{
        fwrite(buf, size, 1, stdout);
}

static int grep_buffer_1(struct grep_opt *opt, const char *name,
                         char *buf, unsigned long size, int collect_hits)
{
        char *bol = buf;
        unsigned long left = size;
        unsigned lno = 1;
        unsigned last_hit = 0;
        int binary_match_only = 0;
        unsigned count = 0;
        int try_lookahead = 0;
        enum grep_context ctx = GREP_CONTEXT_HEAD;
        xdemitconf_t xecfg;

        opt->last_shown = 0;

        if (!opt->output)
                opt->output = std_output;

        if (buffer_is_binary(buf, size)) {
                switch (opt->binary) {
                case GREP_BINARY_DEFAULT:
                        binary_match_only = 1;
                        break;
                case GREP_BINARY_NOMATCH:
                        return 0; /* Assume unmatch */
                        break;
                default:
                        break;
                }
        }

        memset(&xecfg, 0, sizeof(xecfg));
        if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
            !opt->name_only && !binary_match_only && !collect_hits) {
                struct userdiff_driver *drv = userdiff_find_by_path(name);
                if (drv && drv->funcname.pattern) {
                        const struct userdiff_funcname *pe = &drv->funcname;
                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
                        opt->priv = &xecfg;
                }
        }
        try_lookahead = should_lookahead(opt);

        while (left) {
                char *eol, ch;
                int hit;

                /*
                 * look_ahead() skips quicly to the line that possibly
                 * has the next hit; don't call it if we need to do
                 * something more than just skipping the current line
                 * in response to an unmatch for the current line.  E.g.
                 * inside a post-context window, we will show the current
                 * line as a context around the previous hit when it
                 * doesn't hit.
                 */
                if (try_lookahead
                    && !(last_hit
                         && lno <= last_hit + opt->post_context)
                    && look_ahead(opt, &left, &lno, &bol))
                        break;
                eol = end_of_line(bol, &left);
                ch = *eol;
                *eol = 0;

                if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
                        ctx = GREP_CONTEXT_BODY;

                hit = match_line(opt, bol, eol, ctx, collect_hits);
                *eol = ch;

                if (collect_hits)
                        goto next_line;

                /* "grep -v -e foo -e bla" should list lines
                 * that do not have either, so inversion should
                 * be done outside.
                 */
                if (opt->invert)
                        hit = !hit;
                if (opt->unmatch_name_only) {
                        if (hit)
                                return 0;
                        goto next_line;
                }
                if (hit) {
                        count++;
                        if (opt->status_only)
                                return 1;
                        if (binary_match_only) {
                                opt->output(opt, "Binary file ", 12);
                                opt->output(opt, name, strlen(name));
                                opt->output(opt, " matches\n", 9);
                                return 1;
                        }
                        if (opt->name_only) {
                                show_name(opt, name);
                                return 1;
                        }
                        /* Hit at this line.  If we haven't shown the
                         * pre-context lines, we would need to show them.
                         * When asked to do "count", this still show
                         * the context which is nonsense, but the user
                         * deserves to get that ;-).
                         */
                        if (opt->pre_context)
                                show_pre_context(opt, name, buf, bol, lno);
                        else if (opt->funcname)
                                show_funcname_line(opt, name, buf, bol, lno);
                        if (!opt->count)
                                show_line(opt, bol, eol, name, lno, ':');
                        last_hit = lno;
                }
                else if (last_hit &&
                         lno <= last_hit + opt->post_context) {
                        /* If the last hit is within the post context,
                         * we need to show this line.
                         */
                        show_line(opt, bol, eol, name, lno, '-');
                }

        next_line:
                bol = eol + 1;
                if (!left)
                        break;
                left--;
                lno++;
        }

        if (collect_hits)
                return 0;

        if (opt->status_only)
                return 0;
        if (opt->unmatch_name_only) {
                /* We did not see any hit, so we want to show this */
                show_name(opt, name);
                return 1;
        }

        xdiff_clear_find_func(&xecfg);
        opt->priv = NULL;

        /* NEEDSWORK:
         * The real "grep -c foo *.c" gives many "bar.c:0" lines,
         * which feels mostly useless but sometimes useful.  Maybe
         * make it another option?  For now suppress them.
         */
        if (opt->count && count) {
                char buf[32];
                opt->output(opt, name, strlen(name));
                snprintf(buf, sizeof(buf), "%c%u\n",
                         opt->null_following_name ? '\0' : ':', count);
                opt->output(opt, buf, strlen(buf));
        }
        return !!last_hit;
}

static void clr_hit_marker(struct grep_expr *x)
{
        /* All-hit markers are meaningful only at the very top level
         * OR node.
         */
        while (1) {
                x->hit = 0;
                if (x->node != GREP_NODE_OR)
                        return;
                x->u.binary.left->hit = 0;
                x = x->u.binary.right;
        }
}

static int chk_hit_marker(struct grep_expr *x)
{
        /* Top level nodes have hit markers.  See if they all are hits */
        while (1) {
                if (x->node != GREP_NODE_OR)
                        return x->hit;
                if (!x->u.binary.left->hit)
                        return 0;
                x = x->u.binary.right;
        }
}

int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
{
        /*
         * we do not have to do the two-pass grep when we do not check
         * buffer-wide "all-match".
         */
        if (!opt->all_match)
                return grep_buffer_1(opt, name, buf, size, 0);

        /* Otherwise the toplevel "or" terms hit a bit differently.
         * We first clear hit markers from them.
         */
        clr_hit_marker(opt->pattern_expression);
        grep_buffer_1(opt, name, buf, size, 1);

        if (!chk_hit_marker(opt->pattern_expression))
                return 0;

        return grep_buffer_1(opt, name, buf, size, 0);
}