From 4fdc29a88b9923d874375c72774a01a91a7fc253 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Sun, 14 Feb 2016 12:41:51 -0500
Subject: Add brief -help and -version support.

---
 bfs.h   |  3 +++
 eval.c  |  4 ++++
 parse.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/bfs.h b/bfs.h
index 36b12e4..1b3457a 100644
--- a/bfs.h
+++ b/bfs.h
@@ -18,6 +18,9 @@
 #include <sys/types.h>
 #include <time.h>
 
+#define BFS_VERSION "0.0"
+#define BFS_HOMEPAGE "https://github.com/tavianator/bfs"
+
 /**
  * A command line expression.
  */
diff --git a/eval.c b/eval.c
index 0f850fc..63c1348 100644
--- a/eval.c
+++ b/eval.c
@@ -568,6 +568,10 @@ static int infer_fdlimit() {
  * Evaluate the command line.
  */
 int eval_cmdline(const struct cmdline *cmdline) {
+	if (!cmdline->expr) {
+		return 0;
+	}
+
 	int nopenfd = infer_fdlimit();
 
 	struct callback_args args = {
diff --git a/parse.c b/parse.c
index f894d5b..6177e76 100644
--- a/parse.c
+++ b/parse.c
@@ -144,6 +144,8 @@ struct parser_state {
 	bool warn;
 	/** Whether any non-option arguments have been encountered. */
 	bool non_option_seen;
+	/** Whether an information option like -help or -version was passed. */
+	bool just_info;
 
 	/** The current time. */
 	struct timespec now;
@@ -520,6 +522,37 @@ static struct expr *parse_type(struct parser_state *state, const char *option, e
 	return new_test_idata(state, eval, typeflag);
 }
 
+/**
+ * "Parse" -help.
+ */
+static struct expr *parse_help(struct parser_state *state) {
+	printf("Usage: %s [arguments...]\n\n", state->argv[0]);
+
+	printf("bfs is compatible with find; see find -help or man find for help with find-\n"
+	       "compatible options :)\n\n");
+
+	printf("Extra features:\n"
+	       "  -color, -nocolor: Turn on or off file type colorization.\n\n"
+	       "  -hidden, -nohidden: Match hidden files, or filter them out.\n\n");
+
+	printf("%s\n", BFS_HOMEPAGE);
+
+	state->just_info = true;
+	return NULL;
+}
+
+/**
+ * "Parse" -version.
+ */
+static struct expr *parse_version(struct parser_state *state) {
+	printf("bfs %s\n\n", BFS_VERSION);
+
+	printf("%s\n", BFS_HOMEPAGE);
+
+	state->just_info = true;
+	return NULL;
+}
+
 /**
  * LITERAL : OPTION
  *         | TEST
@@ -616,7 +649,9 @@ static struct expr *parse_literal(struct parser_state *state) {
 		break;
 
 	case 'h':
-		if (strcmp(arg, "-hidden") == 0) {
+		if (strcmp(arg, "-help") == 0) {
+			return parse_help(state);
+		} else if (strcmp(arg, "-hidden") == 0) {
 			return new_test(state, eval_hidden);
 		}
 		break;
@@ -693,6 +728,7 @@ static struct expr *parse_literal(struct parser_state *state) {
 		if (strcmp(arg, "-samefile") == 0) {
 			return parse_samefile(state, arg);
 		}
+		break;
 
 	case 't':
 		if (strcmp(arg, "-true") == 0) {
@@ -708,6 +744,12 @@ static struct expr *parse_literal(struct parser_state *state) {
 		}
 		break;
 
+	case 'v':
+		if (strcmp(arg, "-version") == 0) {
+			return parse_version(state);
+		}
+		break;
+
 	case 'w':
 		if (strcmp(arg, "-warn") == 0) {
 			state->warn = true;
@@ -723,6 +765,15 @@ static struct expr *parse_literal(struct parser_state *state) {
 		if (strcmp(arg, "-xtype") == 0) {
 			return parse_type(state, arg, eval_xtype);
 		}
+		break;
+
+	case '-':
+		if (strcmp(arg, "--help") == 0) {
+			return parse_help(state);
+		} else if (strcmp(arg, "--version") == 0) {
+			return parse_version(state);
+		}
+		break;
 	}
 
 	fprintf(stderr, "Unknown argument '%s'.\n", arg);
@@ -955,6 +1006,7 @@ struct cmdline *parse_cmdline(int argc, char *argv[]) {
 		.implicit_print = true,
 		.warn = true,
 		.non_option_seen = false,
+		.just_info = false,
 	};
 
 	if (clock_gettime(CLOCK_REALTIME, &state.now) != 0) {
@@ -965,7 +1017,11 @@ struct cmdline *parse_cmdline(int argc, char *argv[]) {
 	if (skip_paths(&state)) {
 		cmdline->expr = parse_expr(&state);
 		if (!cmdline->expr) {
-			goto fail;
+			if (state.just_info) {
+				goto done;
+			} else {
+				goto fail;
+			}
 		}
 	}
 
@@ -996,6 +1052,7 @@ struct cmdline *parse_cmdline(int argc, char *argv[]) {
 		cmdline->colors = parse_colors(getenv("LS_COLORS"));
 	}
 
+done:
 	return cmdline;
 
 fail:
-- 
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