[PATCH] git-grep: boolean expression on pattern matching.

From

Junio C Hamano <junkio@cox.net>

Date

Jun 30, 2006, 10:08 UTC

Message-ID

<7vsllnj6rh.fsf_-_@assigned-by-dhcp.cox.net>

In-Reply-To

<7v3bdnkrfb.fsf@assigned-by-dhcp.cox.net>

	$ git grep -e _PATTERN --and \( -e atom -e token \)

Signed-off-by: Junio C Hamano <junkio@cox.net>
---

 * OR'ing together, admittably, can be done easily by saying
   something like -e 'atom\|token', so being able to say --and
   as you argued is of more practical importance, and doing
   boolean expression like this might be too much frill.

   Only very lightly tested; it is obviously not slated for
   1.4.1.

 builtin-grep.c |  378 ++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 files changed, 327 insertions(+), 51 deletions(-)

diff --git a/builtin-grep.c b/builtin-grep.c
index 2e7986c..70b1fd2 100644
--- a/builtin-grep.c
+++ b/builtin-grep.c
@@ -82,17 +82,47 @@ static int pathspec_matches(const char *
 	return 0;
 }
 
+enum grep_pat_token {
+	GREP_PATTERN,
+	GREP_AND,
+	GREP_OPEN_PAREN,
+	GREP_CLOSE_PAREN,
+	GREP_NOT,
+	GREP_OR,
+};
+
 struct grep_pat {
 	struct grep_pat *next;
 	const char *origin;
 	int no;
+	enum grep_pat_token token;
 	const char *pattern;
 	regex_t regexp;
 };
 
+enum grep_expr_node {
+	GREP_NODE_ATOM,
+	GREP_NODE_NOT,
+	GREP_NODE_AND,
+	GREP_NODE_OR,
+};
+
+struct grep_expr {
+	enum grep_expr_node node;
+	union {
+		struct grep_pat *atom;
+		struct grep_expr *unary;
+		struct {
+			struct grep_expr *left;
+			struct grep_expr *right;
+		} binary;
+	} u;
+};
+
 struct grep_opt {
 	struct grep_pat *pattern_list;
 	struct grep_pat **pattern_tail;
+	struct grep_expr *pattern_expression;
 	regex_t regexp;
 	unsigned linenum:1;
 	unsigned invert:1;
@@ -105,43 +135,224 @@ #define GREP_BINARY_DEFAULT	0
 #define GREP_BINARY_NOMATCH	1
 #define GREP_BINARY_TEXT	2
 	unsigned binary:2;
+	unsigned extended:1;
 	int regflags;
 	unsigned pre_context;
 	unsigned post_context;
 };
 
 static void add_pattern(struct grep_opt *opt, const char *pat,
-			const char *origin, int no)
+			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;
 }
 
+static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
+{
+	int 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);
+	}
+}
+
+#if DEBUG
+static inline void indent(int in)
+{
+	int i;
+	for (i = 0; i < in; i++) putchar(' ');
+}
+
+static void dump_pattern_exp(struct grep_expr *x, int in)
+{
+	switch (x->node) {
+	case GREP_NODE_ATOM:
+		indent(in);
+		puts(x->u.atom->pattern);
+		break;
+	case GREP_NODE_NOT:
+		indent(in);
+		puts("--not");
+		dump_pattern_exp(x->u.unary, in+1);
+		break;
+	case GREP_NODE_AND:
+		dump_pattern_exp(x->u.binary.left, in+1);
+		indent(in);
+		puts("--and");
+		dump_pattern_exp(x->u.binary.right, in+1);
+		break;
+	case GREP_NODE_OR:
+		dump_pattern_exp(x->u.binary.left, in+1);
+		indent(in);
+		puts("--or");
+		dump_pattern_exp(x->u.binary.right, in+1);
+		break;
+	}
+}
+
+static void looking_at(const char *msg, struct grep_pat **list)
+{
+	struct grep_pat *p = *list;
+	fprintf(stderr, "%s: looking at ", msg);
+	if (!p)
+		fprintf(stderr, "empty\n");
+	else
+		fprintf(stderr, "<%s>\n", p->pattern);
+}
+#else
+#define looking_at(a,b) do {} while(0)
+#endif
+
+static struct grep_expr *compile_pattern_expr(struct grep_pat **);
+static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
+{
+	struct grep_pat *p;
+	struct grep_expr *x;
+
+	looking_at("atom", list);
+
+	p = *list;
+	switch (p->token) {
+	case GREP_PATTERN: /* atom */
+		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_expr(list);
+		if (!x)
+			return NULL;
+		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;
+
+	looking_at("not", list);
+
+	p = *list;
+	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;
+
+	looking_at("and", list);
+
+	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;
+
+	looking_at("or", list);
+
+	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)
+{
+	looking_at("expr", list);
+
+	return compile_pattern_or(list);
+}
+
 static void compile_patterns(struct grep_opt *opt)
 {
 	struct grep_pat *p;
+
+	/* First compile regexps */
 	for (p = opt->pattern_list; p; p = p->next) {
-		int 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);
-		}
+		if (p->token == GREP_PATTERN)
+			compile_regexp(p, opt);
+		else
+			opt->extended = 1;
 	}
+
+	if (!opt->extended)
+		return;
+
+	/* Then bundle them up in an expression.
+	 * A classic recursive descent parser would do.
+	 */
+	p = opt->pattern_list;
+	opt->pattern_expression = compile_pattern_expr(&p);
+#if DEBUG
+	dump_pattern_exp(opt->pattern_expression, 0);
+#endif
+	if (p)
+		die("incomplete pattern expression: %s", p->pattern);
 }
 
 static char *end_of_line(char *cp, unsigned long *left)
@@ -196,6 +407,79 @@ static int fixmatch(const char *pattern,
 	}
 }
 
+static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol)
+{
+	int hit = 0;
+	regmatch_t pmatch[10];
+
+	if (!opt->fixed) {
+		regex_t *exp = &p->regexp;
+		hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
+			       pmatch, 0);
+	}
+	else {
+		hit = !fixmatch(p->pattern, bol, pmatch);
+	}
+
+	if (hit && opt->word_regexp) {
+		/* Match beginning must be either
+		 * beginning of the line, or at word
+		 * boundary (i.e. the last char must
+		 * not be alnum or underscore).
+		 */
+		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");
+		if (pmatch[0].rm_so != 0 &&
+		    word_char(bol[pmatch[0].rm_so-1]))
+			hit = 0;
+		if (pmatch[0].rm_eo != (eol-bol) &&
+		    word_char(bol[pmatch[0].rm_eo]))
+			hit = 0;
+	}
+	return hit;
+}
+
+static int match_expr_eval(struct grep_opt *opt,
+			   struct grep_expr *x,
+			   char *bol, char *eol)
+{
+	switch (x->node) {
+	case GREP_NODE_ATOM:
+		return match_one_pattern(opt, x->u.atom, bol, eol);
+		break;
+	case GREP_NODE_NOT:
+		return !match_expr_eval(opt, x->u.unary, bol, eol);
+	case GREP_NODE_AND:
+		return (match_expr_eval(opt, x->u.binary.left, bol, eol) &&
+			match_expr_eval(opt, x->u.binary.right, bol, eol));
+	case GREP_NODE_OR:
+		return (match_expr_eval(opt, x->u.binary.left, bol, eol) ||
+			match_expr_eval(opt, x->u.binary.right, bol, eol));
+	}
+	die("Unexpected node type (internal error) %d\n", x->node);
+}
+
+static int match_expr(struct grep_opt *opt, char *bol, char *eol)
+{
+	struct grep_expr *x = opt->pattern_expression;
+	return match_expr_eval(opt, x, bol, eol);
+}
+
+static int match_line(struct grep_opt *opt, char *bol, char *eol)
+{
+	struct grep_pat *p;
+	if (opt->extended)
+		return match_expr(opt, bol, eol);
+	for (p = opt->pattern_list; p; p = p->next) {
+		if (match_one_pattern(opt, p, bol, eol))
+			return 1;
+	}
+	return 0;
+}
+
 static int grep_buffer(struct grep_opt *opt, const char *name,
 		       char *buf, unsigned long size)
 {
@@ -231,46 +515,15 @@ static int grep_buffer(struct grep_opt *
 		hunk_mark = "--\n";
 
 	while (left) {
-		regmatch_t pmatch[10];
 		char *eol, ch;
 		int hit = 0;
-		struct grep_pat *p;
 
 		eol = end_of_line(bol, &left);
 		ch = *eol;
 		*eol = 0;
 
-		for (p = opt->pattern_list; p; p = p->next) {
-			if (!opt->fixed) {
-				regex_t *exp = &p->regexp;
-				hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
-					       pmatch, 0);
-			}
-			else {
-				hit = !fixmatch(p->pattern, bol, pmatch);
-			}
+		hit = match_line(opt, bol, eol);
 
-			if (hit && opt->word_regexp) {
-				/* Match beginning must be either
-				 * beginning of the line, or at word
-				 * boundary (i.e. the last char must
-				 * not be alnum or underscore).
-				 */
-				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");
-				if (pmatch[0].rm_so != 0 &&
-				    word_char(bol[pmatch[0].rm_so-1]))
-					hit = 0;
-				if (pmatch[0].rm_eo != (eol-bol) &&
-				    word_char(bol[pmatch[0].rm_eo]))
-					hit = 0;
-			}
-			if (hit)
-				break;
-		}
 		/* "grep -v -e foo -e bla" should list lines
 		 * that do not have either, so inversion should
 		 * be done outside.
@@ -452,6 +705,8 @@ static int external_grep(struct grep_opt
 	char *argptr = randarg;
 	struct grep_pat *p;
 
+	if (opt->extended)
+		return -1;
 	len = nr = 0;
 	push_arg("grep");
 	if (opt->fixed)
@@ -801,16 +1056,36 @@ int cmd_grep(int argc, const char **argv
 				/* ignore empty line like grep does */
 				if (!buf[0])
 					continue;
-				add_pattern(&opt, strdup(buf), argv[1], ++lno);
+				add_pattern(&opt, strdup(buf), argv[1], ++lno,
+					    GREP_PATTERN);
 			}
 			fclose(patterns);
 			argv++;
 			argc--;
 			continue;
 		}
+		if (!strcmp("--not", arg)) {
+			add_pattern(&opt, arg, "command line", 0, GREP_NOT);
+			continue;
+		}
+		if (!strcmp("--and", arg)) {
+			add_pattern(&opt, arg, "command line", 0, GREP_AND);
+			continue;
+		}
+		if (!strcmp("--or", arg))
+			continue; /* no-op */
+		if (!strcmp("(", arg)) {
+			add_pattern(&opt, arg, "command line", 0, GREP_OPEN_PAREN);
+			continue;
+		}
+		if (!strcmp(")", arg)) {
+			add_pattern(&opt, arg, "command line", 0, GREP_CLOSE_PAREN);
+			continue;
+		}
 		if (!strcmp("-e", arg)) {
 			if (1 < argc) {
-				add_pattern(&opt, argv[1], "-e option", 0);
+				add_pattern(&opt, argv[1], "-e option", 0,
+					    GREP_PATTERN);
 				argv++;
 				argc--;
 				continue;
@@ -824,7 +1099,8 @@ int cmd_grep(int argc, const char **argv
 
 		/* First unrecognized non-option token */
 		if (!opt.pattern_list) {
-			add_pattern(&opt, arg, "command line", 0);
+			add_pattern(&opt, arg, "command line", 0,
+				    GREP_PATTERN);
 			break;
 		}
 		else {

-- 
1.4.1.rc2.gfff62