1 files changed, 492 insertions, 0 deletions
diff --git a/src/grab.c b/src/grab.c
new file mode 100644
index 0000000..96b5d9f
--- /dev/null
+++ b/src/grab.c
@@ -0,0 +1,492 @@
+#include <err.h>
+#include <getopt.h>
+#include <libgen.h>
+#include <limits.h>
+#include <locale.h>
+#include <regex.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#if !GRAB_IS_C23
+#	include <assert.h>
+#	include <stdbool.h>
+#	define nullptr NULL
+#endif
+
+#include "da.h"
+
+#ifndef REG_STARTEND
+#	error "REG_STARTEND not defined"
+#endif
+
+#define die(...)  err(EXIT_FAILURE, __VA_ARGS__);
+#define diex(...) errx(EXIT_FAILURE, __VA_ARGS__);
+#define warn(...) \
+	do { \
+		warn(__VA_ARGS__); \
+		rv = EXIT_FAILURE; \
+	} while (0)
+#define streq(a, b) (!strcmp(a, b))
+
+#define EEARLY "Input string terminated prematurely"
+
+struct op {
+	char c;
+	regex_t pat;
+};
+
+struct ops {
+	struct op *buf;
+	size_t len, cap;
+};
+
+struct chars {
+	char *buf;
+	size_t len, cap;
+};
+
+struct sv {
+	char *p;
+	size_t len;
+};
+
+typedef unsigned char uchar;
+typedef void (*cmd_func)(struct sv, struct ops, size_t, const char *);
+
+static void cmdg(struct sv, struct ops, size_t, const char *);
+static void cmdx(struct sv, struct ops, size_t, const char *);
+static void cmdy(struct sv, struct ops, size_t, const char *);
+
+static void grab(struct ops, FILE *, const char *);
+static void putm(struct sv, const char *);
+static regex_t mkregex(char *, size_t);
+static struct ops comppat(char *);
+static char *env_or_default(const char *, const char *);
+#if GIT_GRAB
+static FILE *getfstream(int n, char *v[n]);
+#endif
+
+static bool xisspace(char);
+static char *xstrchrnul(const char *, char);
+
+static int filecnt, rv;
+static bool color, nflag, zflag;
+static bool fflag =
+#if GIT_GRAB
+	true;
+#else
+	false;
+#endif
+
+static const cmd_func op_table[UCHAR_MAX] = {
+	['g'] = cmdg,
+	['v'] = cmdg,
+	['x'] = cmdx,
+	['y'] = cmdy,
+};
+
+static const char esc_table[UCHAR_MAX] = {
+	['\\'] = '\\', ['a'] = '\a', ['b'] = '\b', ['f'] = '\f',
+	['n'] = '\n',  ['r'] = '\r', ['t'] = '\t', ['v'] = '\v',
+};
+
+static void
+usage(const char *s)
+{
+	fprintf(stderr,
+#if GIT_GRAB
+	        "Usage: %s [-nz] pattern [glob ...]\n"
+#else
+	        "Usage: %s [-fnz] pattern [file ...]\n"
+#endif
+	        "       %s -h\n",
+	        s, s);
+	exit(EXIT_FAILURE);
+}
+
+int
+main(int argc, char **argv)
+{
+	int opt;
+	struct ops ops;
+	struct option longopts[] = {
+		{"filenames", no_argument, 0, 'f'},
+		{"help",      no_argument, 0, 'h'},
+		{"newline",   no_argument, 0, 'n'},
+		{"zero",      no_argument, 0, 'z'},
+	};
+
+#if GIT_GRAB
+	char *entry = NULL;
+	size_t len;
+	ssize_t nr;
+	FILE *flist;
+	const char *opts = "hnz";
+#else
+	const char *opts = "fhnz";
+#endif
+
+	argv[0] = basename(argv[0]);
+	if (argc < 2)
+		usage(argv[0]);
+
+	setlocale(LC_ALL, "");
+
+	while ((opt = getopt_long(argc, argv, opts, longopts, nullptr)) != -1) {
+		switch (opt) {
+#if !GIT_GRAB
+		case 'f':
+			fflag = true;
+			break;
+#endif
+		case 'h':
+			execlp("man", "man", "1", argv[0], nullptr);
+			die("execlp: man 1 %s", argv[0]);
+		case 'n':
+			nflag = true;
+			break;
+		case 'z':
+			zflag = true;
+			break;
+		default:
+			usage(argv[0]);
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+	filecnt = argc - 1;
+
+	if (isatty(STDOUT_FILENO) == 1 && !env_or_default("NO_COLOR", nullptr))
+		color = !streq(env_or_default("TERM", ""), "dumb");
+
+	ops = comppat(argv[0]);
+
+#if GIT_GRAB
+	if ((flist = getfstream(argc - 1, argv + 1)) == nullptr)
+		die("getfstream");
+	while ((nr = getdelim(&entry, &len, '\0', flist)) > 0) {
+		FILE *fp;
+
+		if ((fp = fopen(entry, "r")) == nullptr)
+			warn("fopen: %s", entry);
+		else {
+			grab(ops, fp, entry);
+			fclose(fp);
+		}
+	}
+	if (ferror(flist))
+		warn("getdelim");
+#else
+	if (argc == 1)
+		grab(ops, stdin, "-");
+	else {
+		for (int i = 1; i < argc; i++) {
+			FILE *fp;
+
+			if (streq(argv[i], "-")) {
+				grab(ops, stdin, "-");
+			} else if ((fp = fopen(argv[i], "r")) == nullptr) {
+				warn("fopen: %s", argv[i]);
+			} else {
+				grab(ops, fp, argv[i]);
+				fclose(fp);
+			}
+		}
+	}
+#endif
+
+#ifdef GRAB_DEBUG
+	for (size_t i = 0; i < ops.len; i++)
+		regfree(&ops.buf[i].pat);
+	free(ops.buf);
+#endif
+
+	return rv;
+}
+
+struct ops
+comppat(char *s)
+{
+#define skip_ws(p) for (; *(p) && xisspace(*(p)); (p)++)
+	struct ops ops;
+
+	da_init(&ops, 8);
+	skip_ws(s);
+	if (!*s)
+		diex(EEARLY);
+
+	do {
+		char delim;
+		char *p;
+		struct op op;
+
+		op.c = *s;
+		if (!op_table[(uchar)op.c])
+			diex("Invalid operator ‘%c’", *s);
+		if (!(delim = *++s))
+			diex(EEARLY);
+
+		p = ++s;
+		s = xstrchrnul(s, delim);
+		op.pat = mkregex(p, s - p);
+		da_append(&ops, op);
+
+		if (*s)
+			s++;
+		skip_ws(s);
+	} while (*s && *(s + 1));
+
+	return ops;
+#undef skip_ws
+}
+
+void
+grab(struct ops ops, FILE *stream, const char *filename)
+{
+	size_t n;
+	struct chars chars = {0};
+
+	do {
+		static_assert(sizeof(char) == 1, "sizeof(char) != 1; wtf?");
+		chars.cap += BUFSIZ;
+		if ((chars.buf = realloc(chars.buf, chars.cap)) == nullptr)
+			die("realloc");
+		chars.len += n = fread(chars.buf + chars.len, 1, BUFSIZ, stream);
+	} while (n == BUFSIZ);
+
+	if (ferror(stream))
+		warn("fread: %s", filename);
+	else {
+		struct sv sv = {
+			.p = chars.buf,
+			.len = chars.len,
+		};
+		op_table[(uchar)ops.buf[0].c](sv, ops, 0, filename);
+	}
+
+	free(chars.buf);
+}
+
+void
+cmdg(struct sv sv, struct ops ops, size_t i, const char *filename)
+{
+	int r;
+	regmatch_t pm = {
+		.rm_so = 0,
+		.rm_eo = sv.len,
+	};
+	struct op op = ops.buf[i];
+
+	r = regexec(&op.pat, sv.p, 1, &pm, REG_STARTEND);
+	if ((r == REG_NOMATCH && op.c == 'g') || (r != REG_NOMATCH && op.c == 'v'))
+		return;
+
+	if (i + 1 == ops.len)
+		putm(sv, filename);
+	else
+		op_table[(uchar)ops.buf[i + 1].c](sv, ops, i + 1, filename);
+}
+
+void
+cmdx(struct sv sv, struct ops ops, size_t i, const char *filename)
+{
+	regmatch_t pm = {
+		.rm_so = 0,
+		.rm_eo = sv.len,
+	};
+	struct op op = ops.buf[i];
+
+	do {
+		struct sv nsv;
+
+		if (regexec(&op.pat, sv.p, 1, &pm, REG_STARTEND) == REG_NOMATCH)
+			break;
+		nsv = (struct sv){.p = sv.p + pm.rm_so, .len = pm.rm_eo - pm.rm_so};
+		if (i + 1 == ops.len)
+			putm(nsv, filename);
+		else
+			op_table[(uchar)ops.buf[i + 1].c](nsv, ops, i + 1, filename);
+
+		if (pm.rm_so == pm.rm_eo)
+			pm.rm_eo++;
+		pm = (regmatch_t){
+			.rm_so = pm.rm_eo,
+			.rm_eo = sv.len,
+		};
+	} while (pm.rm_so < pm.rm_eo);
+}
+
+void
+cmdy(struct sv sv, struct ops ops, size_t i, const char *filename)
+{
+	regmatch_t pm = {
+		.rm_so = 0,
+		.rm_eo = sv.len,
+	};
+	regmatch_t prev = {
+		.rm_so = 0,
+		.rm_eo = 0,
+	};
+	struct op op = ops.buf[i];
+
+	do {
+		struct sv nsv;
+
+		if (regexec(&op.pat, sv.p, 1, &pm, REG_STARTEND) == REG_NOMATCH)
+			break;
+
+		if (prev.rm_so || prev.rm_eo || pm.rm_so) {
+			nsv = (struct sv){
+				.p = sv.p + prev.rm_eo,
+				.len = pm.rm_so - prev.rm_eo,
+			};
+			if (i + 1 == ops.len)
+				putm(nsv, filename);
+			else
+				op_table[(uchar)ops.buf[i + 1].c](nsv, ops, i + 1, filename);
+		}
+
+		prev = pm;
+		if (pm.rm_so == pm.rm_eo)
+			pm.rm_eo++;
+		pm = (regmatch_t){
+			.rm_so = pm.rm_eo,
+			.rm_eo = sv.len,
+		};
+	} while (pm.rm_so < pm.rm_eo);
+
+	if (prev.rm_eo < pm.rm_eo) {
+		struct sv nsv = {
+			.p = sv.p + pm.rm_so,
+			.len = pm.rm_eo - pm.rm_so,
+		};
+		if (i + 1 == ops.len)
+			putm(nsv, filename);
+		else
+			op_table[(uchar)ops.buf[i + 1].c](nsv, ops, i + 1, filename);
+	}
+}
+
+void
+putm(struct sv sv, const char *filename)
+{
+	static const char *fnc, *sepc;
+
+	if (!fnc) {
+		fnc = env_or_default("GRAB_COLOR_FNAME", "35");
+		sepc = env_or_default("GRAB_COLOR_SEP", "36");
+	}
+
+	if (fflag || filecnt > 1) {
+		if (color) {
+			printf("\33[%sm%s\33[%sm%c\33[0m", fnc, filename, sepc,
+			       zflag ? '\0' : ':');
+		} else
+			printf("%s%c", filename, zflag ? '\0' : ':');
+	}
+	fwrite(sv.p, 1, sv.len, stdout);
+	putchar(zflag ? '\0' : '\n');
+}
+
+regex_t
+mkregex(char *s, size_t n)
+{
+	char c = s[n];
+	int ret, cflags;
+	regex_t r;
+
+	for (size_t i = 0; i < n - 1; i++) {
+		if (s[i] == '\\') {
+			char c = esc_table[(uchar)s[i + 1]];
+			if (c) {
+				for (size_t j = i; j < n - 1; j++)
+					s[j] = s[j + 1];
+				s[i] = c;
+				n--;
+			}
+		}
+	}
+
+	s[n] = 0;
+	cflags = REG_EXTENDED;
+	if (nflag)
+		cflags |= REG_NEWLINE;
+	if ((ret = regcomp(&r, s, cflags)) != 0) {
+		char emsg[128];
+		regerror(ret, &r, emsg, sizeof(emsg));
+		diex("Failed to compile regex: %s", emsg);
+	}
+	s[n] = c;
+
+	return r;
+}
+
+#if GIT_GRAB
+FILE *
+getfstream(int argc, char *argv[argc])
+{
+	pid_t pid;
+	int fds[2];
+	enum {
+		FD_R,
+		FD_W,
+	};
+
+	if (pipe(fds) == -1)
+		die("pipe");
+
+	switch (pid = fork()) {
+	case -1:
+		die("fork");
+	case 0:;
+		size_t len = argc + 5;
+		char **args;
+
+		close(fds[FD_R]);
+		if (dup2(fds[FD_W], STDOUT_FILENO) == -1)
+			die("dup2");
+
+		if (!(args = malloc(len * sizeof(char *))))
+			die("malloc");
+		args[0] = "git";
+		args[1] = "ls-files";
+		args[2] = "-z";
+		args[3] = "--";
+		memcpy(args + 4, argv, argc * sizeof(char *));
+		args[len - 1] = nullptr;
+
+		execvp("git", args);
+		die("execvp: git ls-files -z");
+	}
+
+	close(fds[FD_W]);
+	return fdopen(fds[FD_R], "r");
+}
+#endif
+
+char *
+env_or_default(const char *e, const char *d)
+{
+	const char *s = getenv(e);
+	return (char *)(s && *s ? s : d);
+}
+
+bool
+xisspace(char c)
+{
+	return c == ' ' || c == '\t' || c == '\n';
+}
+
+char *
+xstrchrnul(const char *s, char c)
+{
+	for (; *s; s++) {
+		if (*s == '\\')
+			s++;
+		else if (*s == c)
+			break;
+	}
+	return (char *)s;
+}