xdiff: PATIENCE/HISTOGRAM are not independent option bits
[gitweb.git] / grep.c
diff --git a/grep.c b/grep.c
index 04c777a20c1a8c10417cc9d44e53e5b99dc32a27..b29d09c7f6a5a7f9621fb5287eb07e72ece7f484 100644 (file)
--- a/grep.c
+++ b/grep.c
@@ -1,25 +1,34 @@
 #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->patternlen = strlen(pat);
        p->origin = "header";
        p->no = 0;
        p->token = GREP_PATTERN_HEAD;
        p->field = field;
-       *opt->pattern_tail = p;
-       opt->pattern_tail = &p->next;
+       *opt->header_tail = p;
+       opt->header_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)
+{
+       append_grep_pat(opt, pat, strlen(pat), origin, no, t);
+}
+
+void append_grep_pat(struct grep_opt *opt, const char *pat, size_t patlen,
+                    const char *origin, int no, enum grep_pat_token t)
 {
        struct grep_pat *p = xcalloc(1, sizeof(*p));
        p->pattern = pat;
+       p->patternlen = patlen;
        p->origin = origin;
        p->no = no;
        p->token = t;
@@ -28,11 +37,122 @@ void append_grep_pattern(struct grep_opt *opt, const char *pat,
        p->next = NULL;
 }
 
-static int is_fixed(const char *s)
+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_pat(ret, pat->pattern, pat->patternlen,
+                                       pat->origin, pat->no, pat->token);
+       }
+
+       return ret;
+}
+
+static NORETURN void compile_regexp_failed(const struct grep_pat *p,
+               const char *error)
+{
+       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;
+
+       die("%s'%s': %s", where, p->pattern, error);
+}
+
+#ifdef USE_LIBPCRE
+static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
+{
+       const char *error;
+       int erroffset;
+       int options = 0;
+
+       if (opt->ignore_case)
+               options |= PCRE_CASELESS;
+
+       p->pcre_regexp = pcre_compile(p->pattern, options, &error, &erroffset,
+                       NULL);
+       if (!p->pcre_regexp)
+               compile_regexp_failed(p, error);
+
+       p->pcre_extra_info = pcre_study(p->pcre_regexp, 0, &error);
+       if (!p->pcre_extra_info && error)
+               die("%s", error);
+}
+
+static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
+               regmatch_t *match, int eflags)
+{
+       int ovector[30], ret, flags = 0;
+
+       if (eflags & REG_NOTBOL)
+               flags |= PCRE_NOTBOL;
+
+       ret = pcre_exec(p->pcre_regexp, p->pcre_extra_info, line, eol - line,
+                       0, flags, ovector, ARRAY_SIZE(ovector));
+       if (ret < 0 && ret != PCRE_ERROR_NOMATCH)
+               die("pcre_exec failed with error code %d", ret);
+       if (ret > 0) {
+               ret = 0;
+               match->rm_so = ovector[0];
+               match->rm_eo = ovector[1];
+       }
+
+       return ret;
+}
+
+static void free_pcre_regexp(struct grep_pat *p)
+{
+       pcre_free(p->pcre_regexp);
+       pcre_free(p->pcre_extra_info);
+}
+#else /* !USE_LIBPCRE */
+static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
+{
+       die("cannot use Perl-compatible regexes when not compiled with USE_LIBPCRE");
+}
+
+static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
+               regmatch_t *match, int eflags)
+{
+       return 1;
+}
+
+static void free_pcre_regexp(struct grep_pat *p)
 {
-       while (*s && !is_regex_special(*s))
-               s++;
-       return !*s;
+}
+#endif /* !USE_LIBPCRE */
+
+static int is_fixed(const char *s, size_t len)
+{
+       size_t i;
+
+       /* regcomp cannot accept patterns with NULs so we
+        * consider any pattern containing a NUL fixed.
+        */
+       if (memchr(s, 0, len))
+               return 1;
+
+       for (i = 0; i < len; i++) {
+               if (is_regex_special(s[i]))
+                       return 0;
+       }
+
+       return 1;
 }
 
 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
@@ -40,28 +160,39 @@ 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;
 
-       if (opt->fixed || is_fixed(p->pattern))
+       if (opt->fixed || is_fixed(p->pattern, p->patternlen))
                p->fixed = 1;
-       if (opt->regflags & REG_ICASE)
+       else
                p->fixed = 0;
-       if (p->fixed)
+
+       if (p->fixed) {
+               if (opt->regflags & REG_ICASE || p->ignore_case) {
+                       static char trans[256];
+                       int i;
+                       for (i = 0; i < 256; i++)
+                               trans[i] = tolower(i);
+                       p->kws = kwsalloc(trans);
+               } else {
+                       p->kws = kwsalloc(NULL);
+               }
+               kwsincr(p->kws, p->pattern, p->patternlen);
+               kwsprep(p->kws);
+               return;
+       }
+
+       if (opt->pcre) {
+               compile_pcre_regexp(p, opt);
                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);
+               compile_regexp_failed(p, errbuf);
        }
 }
 
@@ -167,12 +298,73 @@ static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
        return compile_pattern_or(list);
 }
 
-void compile_grep_patterns(struct grep_opt *opt)
+static struct grep_expr *grep_true_expr(void)
+{
+       struct grep_expr *z = xcalloc(1, sizeof(*z));
+       z->node = GREP_NODE_TRUE;
+       return z;
+}
+
+static struct grep_expr *grep_or_expr(struct grep_expr *left, struct grep_expr *right)
+{
+       struct grep_expr *z = xcalloc(1, sizeof(*z));
+       z->node = GREP_NODE_OR;
+       z->u.binary.left = left;
+       z->u.binary.right = right;
+       return z;
+}
+
+static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
 {
        struct grep_pat *p;
+       struct grep_expr *header_expr;
+       struct grep_expr *(header_group[GREP_HEADER_FIELD_MAX]);
+       enum grep_header_field fld;
 
-       if (opt->all_match)
-               opt->extended = 1;
+       if (!opt->header_list)
+               return NULL;
+       p = opt->header_list;
+       for (p = opt->header_list; p; p = p->next) {
+               if (p->token != GREP_PATTERN_HEAD)
+                       die("bug: a non-header pattern in grep header list.");
+               if (p->field < 0 || GREP_HEADER_FIELD_MAX <= p->field)
+                       die("bug: unknown header field %d", p->field);
+               compile_regexp(p, opt);
+       }
+
+       for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++)
+               header_group[fld] = NULL;
+
+       for (p = opt->header_list; p; p = p->next) {
+               struct grep_expr *h;
+               struct grep_pat *pp = p;
+
+               h = compile_pattern_atom(&pp);
+               if (!h || pp != p->next)
+                       die("bug: malformed header expr");
+               if (!header_group[p->field]) {
+                       header_group[p->field] = h;
+                       continue;
+               }
+               header_group[p->field] = grep_or_expr(h, header_group[p->field]);
+       }
+
+       header_expr = NULL;
+
+       for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++) {
+               if (!header_group[fld])
+                       continue;
+               if (!header_expr)
+                       header_expr = grep_true_expr();
+               header_expr = grep_or_expr(header_group[fld], header_expr);
+       }
+       return header_expr;
+}
+
+void compile_grep_patterns(struct grep_opt *opt)
+{
+       struct grep_pat *p;
+       struct grep_expr *header_expr = prep_header_patterns(opt);
 
        for (p = opt->pattern_list; p; p = p->next) {
                switch (p->token) {
@@ -187,22 +379,32 @@ void compile_grep_patterns(struct grep_opt *opt)
                }
        }
 
-       if (!opt->extended)
+       if (opt->all_match || header_expr)
+               opt->extended = 1;
+       else 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);
+
+       if (!header_expr)
+               return;
+
+       if (!opt->pattern_expression)
+               opt->pattern_expression = header_expr;
+       else
+               opt->pattern_expression = grep_or_expr(opt->pattern_expression,
+                                                      header_expr);
+       opt->all_match = 1;
 }
 
 static void free_pattern_expr(struct grep_expr *x)
 {
        switch (x->node) {
+       case GREP_NODE_TRUE:
        case GREP_NODE_ATOM:
                break;
        case GREP_NODE_NOT:
@@ -227,7 +429,12 @@ void free_grep_patterns(struct grep_opt *opt)
                case GREP_PATTERN: /* atom */
                case GREP_PATTERN_HEAD:
                case GREP_PATTERN_BODY:
-                       regfree(&p->regexp);
+                       if (p->kws)
+                               kwsfree(p->kws);
+                       else if (p->pcre_regexp)
+                               free_pcre_regexp(p);
+                       else
+                               regfree(&p->regexp);
                        break;
                default:
                        break;
@@ -256,25 +463,72 @@ static int word_char(char ch)
        return isalnum(ch) || ch == '_';
 }
 
+static void output_color(struct grep_opt *opt, const void *data, size_t size,
+                        const char *color)
+{
+       if (want_color(opt->color) && color && color[0]) {
+               opt->output(opt, color, strlen(color));
+               opt->output(opt, data, size);
+               opt->output(opt, GIT_COLOR_RESET, strlen(GIT_COLOR_RESET));
+       } else
+               opt->output(opt, data, size);
+}
+
+static void output_sep(struct grep_opt *opt, char sign)
+{
+       if (opt->null_following_name)
+               opt->output(opt, "\0", 1);
+       else
+               output_color(opt, &sign, 1, opt->color_sep);
+}
+
 static void show_name(struct grep_opt *opt, const char *name)
 {
-       printf("%s%c", name, opt->null_following_name ? '\0' : '\n');
+       output_color(opt, name, strlen(name), opt->color_filename);
+       opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 }
 
-static int fixmatch(const char *pattern, char *line, regmatch_t *match)
+static int fixmatch(struct grep_pat *p, char *line, char *eol,
+                   regmatch_t *match)
 {
-       char *hit = strstr(line, pattern);
-       if (!hit) {
+       struct kwsmatch kwsm;
+       size_t offset = kwsexec(p->kws, line, eol - line, &kwsm);
+       if (offset == -1) {
                match->rm_so = match->rm_eo = -1;
                return REG_NOMATCH;
-       }
-       else {
-               match->rm_so = hit - line;
-               match->rm_eo = match->rm_so + strlen(pattern);
+       } else {
+               match->rm_so = offset;
+               match->rm_eo = match->rm_so + kwsm.size[0];
                return 0;
        }
 }
 
+static int regmatch(const regex_t *preg, char *line, char *eol,
+                   regmatch_t *match, int eflags)
+{
+#ifdef REG_STARTEND
+       match->rm_so = 0;
+       match->rm_eo = eol - line;
+       eflags |= REG_STARTEND;
+#endif
+       return regexec(preg, line, 1, match, eflags);
+}
+
+static int patmatch(struct grep_pat *p, char *line, char *eol,
+                   regmatch_t *match, int eflags)
+{
+       int hit;
+
+       if (p->fixed)
+               hit = !fixmatch(p, line, eol, match);
+       else if (p->pcre_regexp)
+               hit = !pcrematch(p, line, eol, match, eflags);
+       else
+               hit = !regmatch(&p->regexp, line, eol, match, eflags);
+
+       return hit;
+}
+
 static int strip_timestamp(char *bol, char **eol_p)
 {
        char *eol = *eol_p;
@@ -305,6 +559,7 @@ static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 {
        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)))
@@ -323,14 +578,11 @@ static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
        }
 
  again:
-       if (p->fixed)
-               hit = !fixmatch(p->pattern, bol, pmatch);
-       else
-               hit = !regexec(&p->regexp, bol, 1, pmatch, eflags);
+       hit = patmatch(p, bol, eol, pmatch, eflags);
 
        if (hit && p->word_regexp) {
                if ((pmatch[0].rm_so < 0) ||
-                   (eol - bol) <= pmatch[0].rm_so ||
+                   (eol - bol) < pmatch[0].rm_so ||
                    (pmatch[0].rm_eo < 0) ||
                    (eol - bol) < pmatch[0].rm_eo)
                        die("regexp returned nonsense");
@@ -349,6 +601,10 @@ static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
                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
@@ -359,12 +615,17 @@ static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
                        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;
 }
 
@@ -377,6 +638,9 @@ static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
        if (!x)
                die("Not a valid grep expression");
        switch (x->node) {
+       case GREP_NODE_TRUE:
+               h = 1;
+               break;
        case GREP_NODE_ATOM:
                h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
                break;
@@ -479,33 +743,221 @@ static void show_line(struct grep_opt *opt, char *bol, char *eol,
                      const char *name, unsigned lno, char sign)
 {
        int rest = eol - bol;
+       char *line_color = NULL;
+
+       if (opt->file_break && opt->last_shown == 0) {
+               if (opt->show_hunk_mark)
+                       opt->output(opt, "\n", 1);
+       } else if (opt->pre_context || opt->post_context || opt->funcbody) {
+               if (opt->last_shown == 0) {
+                       if (opt->show_hunk_mark) {
+                               output_color(opt, "--", 2, opt->color_sep);
+                               opt->output(opt, "\n", 1);
+                       }
+               } else if (lno > opt->last_shown + 1) {
+                       output_color(opt, "--", 2, opt->color_sep);
+                       opt->output(opt, "\n", 1);
+               }
+       }
+       if (opt->heading && opt->last_shown == 0) {
+               output_color(opt, name, strlen(name), opt->color_filename);
+               opt->output(opt, "\n", 1);
+       }
+       opt->last_shown = lno;
 
-       if (opt->null_following_name)
-               sign = '\0';
-       if (opt->pathname)
-               printf("%s%c", name, sign);
-       if (opt->linenum)
-               printf("%d%c", lno, sign);
+       if (!opt->heading && opt->pathname) {
+               output_color(opt, name, strlen(name), opt->color_filename);
+               output_sep(opt, sign);
+       }
+       if (opt->linenum) {
+               char buf[32];
+               snprintf(buf, sizeof(buf), "%d", lno);
+               output_color(opt, buf, strlen(buf), opt->color_lineno);
+               output_sep(opt, sign);
+       }
        if (opt->color) {
                regmatch_t match;
                enum grep_context ctx = GREP_CONTEXT_BODY;
                int ch = *eol;
                int eflags = 0;
 
+               if (sign == ':')
+                       line_color = opt->color_selected;
+               else if (sign == '-')
+                       line_color = opt->color_context;
+               else if (sign == '=')
+                       line_color = opt->color_function;
                *eol = '\0';
                while (next_match(opt, bol, eol, ctx, &match, eflags)) {
-                       printf("%.*s%s%.*s%s",
-                              (int)match.rm_so, bol,
-                              opt->color_match,
-                              (int)(match.rm_eo - match.rm_so), bol + match.rm_so,
-                              GIT_COLOR_RESET);
+                       if (match.rm_so == match.rm_eo)
+                               break;
+
+                       output_color(opt, bol, match.rm_so, line_color);
+                       output_color(opt, bol + match.rm_so,
+                                    match.rm_eo - match.rm_so,
+                                    opt->color_match);
                        bol += match.rm_eo;
                        rest -= match.rm_eo;
                        eflags = REG_NOTBOL;
                }
                *eol = ch;
        }
-       printf("%.*s\n", rest, bol);
+       output_color(opt, bol, rest, line_color);
+       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, char *end, unsigned lno)
+{
+       unsigned cur = lno, from = 1, funcname_lno = 0;
+       int funcname_needed = !!opt->funcname;
+
+       if (opt->funcbody && !match_funcname(opt, bol, end))
+               funcname_needed = 2;
+
+       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 > (funcname_needed == 2 ? opt->last_shown + 1 : 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;
+
+               hit = patmatch(p, bol, bol + *left_p, &m, 0);
+               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;
+
+       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,
@@ -514,39 +966,78 @@ static int grep_buffer_1(struct grep_opt *opt, const char *name,
        char *bol = buf;
        unsigned long left = size;
        unsigned lno = 1;
-       struct pre_context_line {
-               char *bol;
-               char *eol;
-       } *prev = NULL, *pcl;
        unsigned last_hit = 0;
-       unsigned last_shown = 0;
        int binary_match_only = 0;
-       const char *hunk_mark = "";
        unsigned count = 0;
+       int try_lookahead = 0;
+       int show_function = 0;
        enum grep_context ctx = GREP_CONTEXT_HEAD;
+       xdemitconf_t xecfg;
+
+       if (!opt->output)
+               opt->output = std_output;
+
+       if (opt->pre_context || opt->post_context || opt->file_break ||
+           opt->funcbody) {
+               /* Show hunk marks, except for the first file. */
+               if (opt->last_shown)
+                       opt->show_hunk_mark = 1;
+               /*
+                * If we're using threads then we can't easily identify
+                * the first file.  Always put hunk marks in that case
+                * and skip the very first one later in work_done().
+                */
+               if (opt->output != std_output)
+                       opt->show_hunk_mark = 1;
+       }
+       opt->last_shown = 0;
 
-       if (buffer_is_binary(buf, size)) {
-               switch (opt->binary) {
-               case GREP_BINARY_DEFAULT:
+       switch (opt->binary) {
+       case GREP_BINARY_DEFAULT:
+               if (buffer_is_binary(buf, size))
                        binary_match_only = 1;
-                       break;
-               case GREP_BINARY_NOMATCH:
+               break;
+       case GREP_BINARY_NOMATCH:
+               if (buffer_is_binary(buf, size))
                        return 0; /* Assume unmatch */
-                       break;
-               default:
-                       break;
-               }
+               break;
+       case GREP_BINARY_TEXT:
+               break;
+       default:
+               die("bug: unknown binary handling mode");
        }
 
-       if (opt->pre_context)
-               prev = xcalloc(opt->pre_context, sizeof(*prev));
-       if (opt->pre_context || opt->post_context)
-               hunk_mark = "--\n";
+       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 quickly 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
+                        && (show_function ||
+                            lno <= last_hit + opt->post_context))
+                   && look_ahead(opt, &left, &lno, &bol))
+                       break;
                eol = end_of_line(bol, &left);
                ch = *eol;
                *eol = 0;
@@ -575,59 +1066,40 @@ static int grep_buffer_1(struct grep_opt *opt, const char *name,
                        count++;
                        if (opt->status_only)
                                return 1;
-                       if (binary_match_only) {
-                               printf("Binary file %s matches\n", name);
-                               return 1;
-                       }
                        if (opt->name_only) {
                                show_name(opt, name);
                                return 1;
                        }
+                       if (opt->count)
+                               goto next_line;
+                       if (binary_match_only) {
+                               opt->output(opt, "Binary file ", 12);
+                               output_color(opt, name, strlen(name),
+                                            opt->color_filename);
+                               opt->output(opt, " matches\n", 9);
+                               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) {
-                               unsigned from;
-                               if (opt->pre_context < lno)
-                                       from = lno - opt->pre_context;
-                               else
-                                       from = 1;
-                               if (from <= last_shown)
-                                       from = last_shown + 1;
-                               if (last_shown && from != last_shown + 1)
-                                       fputs(hunk_mark, stdout);
-                               while (from < lno) {
-                                       pcl = &prev[lno-from-1];
-                                       show_line(opt, pcl->bol, pcl->eol,
-                                                 name, from, '-');
-                                       from++;
-                               }
-                               last_shown = lno-1;
-                       }
-                       if (last_shown && lno != last_shown + 1)
-                               fputs(hunk_mark, stdout);
-                       if (!opt->count)
-                               show_line(opt, bol, eol, name, lno, ':');
-                       last_shown = last_hit = lno;
+                       if (opt->pre_context || opt->funcbody)
+                               show_pre_context(opt, name, buf, bol, eol, lno);
+                       else if (opt->funcname)
+                               show_funcname_line(opt, name, buf, bol, lno);
+                       show_line(opt, bol, eol, name, lno, ':');
+                       last_hit = lno;
+                       if (opt->funcbody)
+                               show_function = 1;
+                       goto next_line;
                }
-               else if (last_hit &&
-                        lno <= last_hit + opt->post_context) {
+               if (show_function && match_funcname(opt, bol, eol))
+                       show_function = 0;
+               if (show_function ||
+                   (last_hit && lno <= last_hit + opt->post_context)) {
                        /* If the last hit is within the post context,
                         * we need to show this line.
                         */
-                       if (last_shown && lno != last_shown + 1)
-                               fputs(hunk_mark, stdout);
                        show_line(opt, bol, eol, name, lno, '-');
-                       last_shown = lno;
-               }
-               if (opt->pre_context) {
-                       memmove(prev+1, prev,
-                               (opt->pre_context-1) * sizeof(*prev));
-                       prev->bol = bol;
-                       prev->eol = eol;
                }
 
        next_line:
@@ -638,7 +1110,6 @@ static int grep_buffer_1(struct grep_opt *opt, const char *name,
                lno++;
        }
 
-       free(prev);
        if (collect_hits)
                return 0;
 
@@ -650,14 +1121,22 @@ static int grep_buffer_1(struct grep_opt *opt, const char *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)
-               printf("%s%c%u\n", name,
-                      opt->null_following_name ? '\0' : ':', count);
+       if (opt->count && count) {
+               char buf[32];
+               output_color(opt, name, strlen(name), opt->color_filename);
+               output_sep(opt, ':');
+               snprintf(buf, sizeof(buf), "%u\n", count);
+               opt->output(opt, buf, strlen(buf));
+               return 1;
+       }
        return !!last_hit;
 }