grep: implement -m MAX_MATCHES; fix help text

grep_file                                            771     822     +51
packed_usage                                       22573   22610     +37
.rodata                                           128058  128090     +32
grep_main                                            842     853     +11
max_matches                                            -       4      +4
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/0 up/down: 135/0)             Total: 135 bytes

diff --git a/findutils/grep.c b/findutils/grep.c
index 7bade87cb6066f4486ae381c7d11867f11b222c1..e543ee07fcb532c13586d830e8e7267904e2ba22 100644 (file)
--- a/findutils/grep.c
+++ b/findutils/grep.c
@@ -24,7 +24,7 @@
 
 /* options */
 #define OPTSTR_GREP \
-       "lnqvscFiHhe:f:Lor" \
+       "lnqvscFiHhe:f:Lorm:" \
        USE_FEATURE_GREP_CONTEXT("A:B:C:") \
        USE_FEATURE_GREP_EGREP_ALIAS("E") \
        USE_DESKTOP("w") \
@@ -33,26 +33,27 @@
 /* ignored: -I "assume binary files have no matches" */
 
 enum {
-       OPTBIT_l,
-       OPTBIT_n,
-       OPTBIT_q,
-       OPTBIT_v,
-       OPTBIT_s,
-       OPTBIT_c,
-       OPTBIT_F,
-       OPTBIT_i,
-       OPTBIT_H,
-       OPTBIT_h,
-       OPTBIT_e,
-       OPTBIT_f,
-       OPTBIT_L,
-       OPTBIT_o,
-       OPTBIT_r,
-       USE_FEATURE_GREP_CONTEXT(    OPTBIT_A ,)
-       USE_FEATURE_GREP_CONTEXT(    OPTBIT_B ,)
-       USE_FEATURE_GREP_CONTEXT(    OPTBIT_C ,)
-       USE_FEATURE_GREP_EGREP_ALIAS(OPTBIT_E ,)
-       USE_DESKTOP(                 OPTBIT_w ,)
+       OPTBIT_l, /* list matched file names only */
+       OPTBIT_n, /* print line# */
+       OPTBIT_q, /* quiet - exit(0) of first match */
+       OPTBIT_v, /* invert the match, to select non-matching lines */
+       OPTBIT_s, /* suppress errors about file open errors */
+       OPTBIT_c, /* count matches per file (suppresses normal output) */
+       OPTBIT_F, /* literal match */
+       OPTBIT_i, /* case-insensitive */
+       OPTBIT_H, /* force filename display */
+       OPTBIT_h, /* inhibit filename display */
+       OPTBIT_e, /* -e PATTERN */
+       OPTBIT_f, /* -f FILE_WITH_PATTERNS */
+       OPTBIT_L, /* list unmatched file names only */
+       OPTBIT_o, /* show only matching parts of lines */
+       OPTBIT_r, /* recurse dirs */
+       OPTBIT_m, /* -m MAX_MATCHES */
+       USE_FEATURE_GREP_CONTEXT(    OPTBIT_A ,) /* -A NUM: after-match context */
+       USE_FEATURE_GREP_CONTEXT(    OPTBIT_B ,) /* -B NUM: before-match context */
+       USE_FEATURE_GREP_CONTEXT(    OPTBIT_C ,) /* -C NUM: -A and -B combined */
+       USE_FEATURE_GREP_EGREP_ALIAS(OPTBIT_E ,) /* extended regexp */
+       USE_DESKTOP(                 OPTBIT_w ,) /* whole word match */
        OPT_l = 1 << OPTBIT_l,
        OPT_n = 1 << OPTBIT_n,
        OPT_q = 1 << OPTBIT_q,
@@ -68,6 +69,7 @@ enum {
        OPT_L = 1 << OPTBIT_L,
        OPT_o = 1 << OPTBIT_o,
        OPT_r = 1 << OPTBIT_r,
+       OPT_m = 1 << OPTBIT_m,
        OPT_A = USE_FEATURE_GREP_CONTEXT(    (1 << OPTBIT_A)) + 0,
        OPT_B = USE_FEATURE_GREP_CONTEXT(    (1 << OPTBIT_B)) + 0,
        OPT_C = USE_FEATURE_GREP_CONTEXT(    (1 << OPTBIT_C)) + 0,
@@ -85,6 +87,7 @@ enum {
 
 typedef unsigned char byte_t;
 
+static int max_matches;
 static int reflags;
 static byte_t invert_search;
 static byte_t print_filename;
@@ -97,7 +100,6 @@ static int lines_after;
 static char **before_buf;
 static int last_line_printed;
 #endif /* ENABLE_FEATURE_GREP_CONTEXT */
-
 /* globals used internally */
 static llist_t *pattern_head;   /* growable list of patterns to match */
 static const char *cur_file;    /* the current file we are reading */
@@ -146,6 +148,8 @@ static int grep_file(FILE *file)
        int print_n_lines_after = 0;
        int curpos = 0; /* track where we are in the circular 'before' buffer */
        int idx = 0; /* used for iteration through the circular buffer */
+#else
+       enum { print_n_lines_after = 0 };
 #endif /* ENABLE_FEATURE_GREP_CONTEXT */
 
        while ((line = xmalloc_getline(file)) != NULL) {
@@ -212,6 +216,12 @@ static int grep_file(FILE *file)
                                return 1; /* one match */
                        }
 
+#if ENABLE_FEATURE_GREP_CONTEXT
+                       /* Were we printing context and saw next (unwanted) match? */
+                       if ((option_mask32 & OPT_m) && nmatches > max_matches)
+                               break;
+#endif
+
                        /* print the matched line */
                        if (PRINT_MATCH_COUNTS == 0) {
 #if ENABLE_FEATURE_GREP_CONTEXT
@@ -255,7 +265,7 @@ static int grep_file(FILE *file)
 #if ENABLE_FEATURE_GREP_CONTEXT
                else { /* no match */
                        /* if we need to print some context lines after the last match, do so */
-                       if (print_n_lines_after /* && (last_line_printed != linenum) */ ) {
+                       if (print_n_lines_after) {
                                print_line(line, linenum, '-');
                                print_n_lines_after--;
                        } else if (lines_before) {
@@ -264,12 +274,17 @@ static int grep_file(FILE *file)
                                before_buf[curpos] = line;
                                curpos = (curpos + 1) % lines_before;
                                /* avoid free(line) - we took line */
-                               continue;
+                               line = NULL;
                        }
                }
 
 #endif /* ENABLE_FEATURE_GREP_CONTEXT */
                free(line);
+
+               /* Did we print all context after last requested match? */
+               if ((option_mask32 & OPT_m)
+                && !print_n_lines_after && nmatches == max_matches)
+                       break;
        }
 
        /* special-case file post-processing for options where we don't print line
@@ -311,7 +326,6 @@ static char * add_grep_list_data(char *pattern)
        return (char *)gl;
 }
 
-
 static void load_regexes_from_file(llist_t *fopt)
 {
        char *line;
@@ -365,6 +379,7 @@ int grep_main(int argc, char **argv)
 {
        FILE *file;
        int matched;
+       char *mopt;
        llist_t *fopt = NULL;
 
        /* do normal option parsing */
@@ -376,7 +391,7 @@ int grep_main(int argc, char **argv)
        opt_complementary = "H-h:e::f::C-AB";
        getopt32(argc, argv,
                OPTSTR_GREP,
-               &pattern_head, &fopt,
+               &pattern_head, &fopt, &mopt,
                &slines_after, &slines_before, &Copt);
 
        if (option_mask32 & OPT_C) {
@@ -405,8 +420,11 @@ int grep_main(int argc, char **argv)
        /* with auto sanity checks */
        opt_complementary = "H-h:e::f::c-n:q-n:l-n";
        getopt32(argc, argv, OPTSTR_GREP,
-               &pattern_head, &fopt);
+               &pattern_head, &fopt, &mopt);
 #endif
+       if (option_mask32 & OPT_m) {
+               max_matches = xatoi_u(mopt);
+       }
        invert_search = ((option_mask32 & OPT_v) != 0); /* 0 | 1 */
 
        if (pattern_head != NULL) {
@@ -487,12 +505,7 @@ int grep_main(int argc, char **argv)
                }
                matched += grep_file(file);
                fclose_if_not_stdin(file);
- grep_done:
-               if (matched < 0) {
-                       /* we found a match but were told to be quiet, stop here and
-                       * return success */
-                       break;
-               }
+ grep_done: ;
        }
 
        /* destroy all the elments in the pattern list */
@@ -512,10 +525,6 @@ int grep_main(int argc, char **argv)
                }
        }
        /* 0 = success, 1 = failed, 2 = error */
-       /* If the -q option is specified, the exit status shall be zero
-        * if an input line is selected, even if an error was detected.  */
-       if (BE_QUIET && matched)
-               return 0;
        if (open_errors)
                return 2;
        return !matched; /* invert return value 0 = success, 1 = failed */

diff --git a/include/usage.h b/include/usage.h
index 68325046ff3aa03b9341873011a895f67a42b7b5..bd9cb990875c53457c321c90af338b37412b4fbc 100644 (file)
--- a/include/usage.h
+++ b/include/usage.h
@@ -1164,14 +1164,15 @@
        "\n     -v      Select non-matching lines" \
        "\n     -s      Suppress file open/read error messages" \
        "\n     -c      Only print count of matching lines" \
-       "\n     -f      Read PATTERN from file" \
        "\n     -o      Show only the part of a line that matches PATTERN" \
+       "\n     -m MAX  Match up to MAX times per file" \
        USE_DESKTOP( \
        "\n     -w      Match whole words only") \
-       "\n     -e      PATTERN is a regular expression" \
        "\n     -F      PATTERN is a set of newline-separated strings" \
        USE_FEATURE_GREP_EGREP_ALIAS( \
        "\n     -E      PATTERN is an extended regular expression") \
+       "\n     -e PTRN Pattern to match" \
+       "\n     -f FILE Read pattern from file" \
        USE_FEATURE_GREP_CONTEXT( \
        "\n     -A      Print NUM lines of trailing context" \
        "\n     -B      Print NUM lines of leading context" \