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authorJunio C Hamano <junkio@cox.net>2006-09-17 23:02:52 (GMT)
committerJunio C Hamano <junkio@cox.net>2006-09-20 18:14:38 (GMT)
commit83b5d2f5b0c95fe102bc3d1cc2947abbdf5e5c5b (patch)
tree16348287b2cb6ebdba2e5068467b6b592b3ec3c7 /grep.c
parent62e27f273d66afa996cb7aee6cdb25fbedc053f6 (diff)
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builtin-grep: make pieces of it available as library.
This makes three functions and associated option structures from builtin-grep available from other parts of the system. * options to drive built-in grep engine is stored in struct grep_opt; * pattern strings and extended grep expressions are added to struct grep_opt with append_grep_pattern(); * when finished calling append_grep_pattern(), call compile_grep_patterns() to prepare for execution; * call grep_buffer() to find matches in the in-core buffer. This also adds an internal option "status_only" to grep_opt, which suppresses any output from grep_buffer(). Callers of the function as library can use it to check if there is a match without producing any output. Signed-off-by: Junio C Hamano <junkio@cox.net>
Diffstat (limited to 'grep.c')
-rw-r--r--grep.c440
1 files changed, 440 insertions, 0 deletions
diff --git a/grep.c b/grep.c
new file mode 100644
index 0000000..61db6e1
--- /dev/null
+++ b/grep.c
@@ -0,0 +1,440 @@
+#include "cache.h"
+#include <regex.h>
+#include "grep.h"
+
+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;
+}
+
+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);
+ }
+}
+
+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;
+
+ 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;
+
+ 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;
+
+ 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->fixed)
+ return;
+
+ /* First compile regexps */
+ for (p = opt->pattern_list; p; p = p->next) {
+ 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 (p)
+ die("incomplete pattern expression: %s", p->pattern);
+}
+
+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_line(struct grep_opt *opt, const char *bol, const char *eol,
+ const char *name, unsigned lno, char sign)
+{
+ if (opt->pathname)
+ printf("%s%c", name, sign);
+ if (opt->linenum)
+ printf("%d%c", lno, sign);
+ printf("%.*s\n", (int)(eol-bol), bol);
+}
+
+/*
+ * NEEDSWORK: share code with diff.c
+ */
+#define FIRST_FEW_BYTES 8000
+static int buffer_is_binary(const char *ptr, unsigned long size)
+{
+ if (FIRST_FEW_BYTES < size)
+ size = FIRST_FEW_BYTES;
+ return !!memchr(ptr, 0, size);
+}
+
+static int fixmatch(const char *pattern, char *line, regmatch_t *match)
+{
+ char *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 match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol)
+{
+ int hit = 0;
+ int at_true_bol = 1;
+ regmatch_t pmatch[10];
+
+ again:
+ 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) {
+ 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 && at_true_bol) ||
+ !word_char(bol[pmatch[0].rm_so-1])) &&
+ ((pmatch[0].rm_eo == (eol-bol)) ||
+ !word_char(bol[pmatch[0].rm_eo])) )
+ ;
+ else
+ 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!
+ */
+ bol = pmatch[0].rm_so + bol + 1;
+ at_true_bol = 0;
+ goto again;
+ }
+ }
+ 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;
+}
+
+int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
+{
+ 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;
+
+ 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;
+ }
+ }
+
+ if (opt->pre_context)
+ prev = xcalloc(opt->pre_context, sizeof(*prev));
+ if (opt->pre_context || opt->post_context)
+ hunk_mark = "--\n";
+
+ while (left) {
+ char *eol, ch;
+ int hit = 0;
+
+ eol = end_of_line(bol, &left);
+ ch = *eol;
+ *eol = 0;
+
+ hit = match_line(opt, bol, eol);
+ *eol = ch;
+
+ /* "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) {
+ printf("Binary file %s matches\n", name);
+ return 1;
+ }
+ if (opt->name_only) {
+ printf("%s\n", 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) {
+ 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)
+ printf(hunk_mark);
+ 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)
+ printf(hunk_mark);
+ if (!opt->count)
+ show_line(opt, bol, eol, name, lno, ':');
+ last_shown = 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.
+ */
+ if (last_shown && lno != last_shown + 1)
+ printf(hunk_mark);
+ 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:
+ bol = eol + 1;
+ if (!left)
+ break;
+ left--;
+ lno++;
+ }
+
+ if (opt->status_only)
+ return 0;
+ if (opt->unmatch_name_only) {
+ /* We did not see any hit, so we want to show this */
+ printf("%s\n", name);
+ return 1;
+ }
+
+ /* 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:%u\n", name, count);
+ return !!last_hit;
+}
+