From 132dc9eaf7d6aa9e7892d9b55889f762f1140f4d Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Sat, 30 Jan 2016 14:00:02 -0500
Subject: Implement -empty.

---
 bfs.h    |  1 +
 eval.c   | 44 ++++++++++++++++++++++++++++++++++++++++++++
 parse.c  |  2 ++
 tests.sh |  7 ++++++-
 4 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/bfs.h b/bfs.h
index aedd2c0..441993b 100644
--- a/bfs.h
+++ b/bfs.h
@@ -97,6 +97,7 @@ void free_cmdline(cmdline *cl);
 // Predicate evaluation functions
 bool eval_access(const expression *expr, eval_state *state);
 bool eval_delete(const expression *expr, eval_state *state);
+bool eval_empty(const expression *expr, eval_state *state);
 bool eval_false(const expression *expr, eval_state *state);
 bool eval_hidden(const expression *expr, eval_state *state);
 bool eval_name(const expression *expr, eval_state *state);
diff --git a/eval.c b/eval.c
index 56238ea..417bfc3 100644
--- a/eval.c
+++ b/eval.c
@@ -1,5 +1,6 @@
 #include "bfs.h"
 #include "bftw.h"
+#include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <fnmatch.h>
@@ -77,6 +78,49 @@ bool eval_delete(const expression *expr, eval_state *state) {
 	return true;
 }
 
+/**
+ * -empty test.
+ */
+bool eval_empty(const expression *expr, eval_state *state) {
+	bool ret = false;
+	struct BFTW *ftwbuf = state->ftwbuf;
+
+	if (ftwbuf->typeflag == BFTW_DIR) {
+		int dfd = openat(ftwbuf->at_fd, ftwbuf->at_path, O_DIRECTORY);
+		if (dfd < 0) {
+			perror("openat()");
+			goto done;
+		}
+
+		DIR *dir = fdopendir(dfd);
+		if (!dir) {
+			perror("fdopendir()");
+			close(dfd);
+			goto done;
+		}
+
+		ret = true;
+
+		struct dirent *de;
+		while ((de = readdir(dir)) != NULL) {
+			if (strcmp(de->d_name, ".") != 0 && strcmp(de->d_name, "..") != 0) {
+				ret = false;
+				break;
+			}
+		}
+
+		closedir(dir);
+	} else {
+		fill_statbuf(state);
+		if (ftwbuf->statbuf) {
+			ret = ftwbuf->statbuf->st_size == 0;
+		}
+	}
+
+done:
+	return ret;
+}
+
 /**
  * -prune action.
  */
diff --git a/parse.c b/parse.c
index 348ddd8..5425afa 100644
--- a/parse.c
+++ b/parse.c
@@ -348,6 +348,8 @@ static expression *parse_literal(parser_state *state) {
 	} else if (strcmp(arg, "-d") == 0 || strcmp(arg, "-depth") == 0) {
 		state->cl->flags |= BFTW_DEPTH;
 		return new_option(state, arg);
+	} else if (strcmp(arg, "-empty") == 0) {
+		return new_test(state, eval_empty);
 	} else if (strcmp(arg, "-executable") == 0) {
 		return new_test_idata(state, eval_access, X_OK);
 	} else if (strcmp(arg, "-false") == 0) {
diff --git a/tests.sh b/tests.sh
index 90ef066..bb24fe0 100755
--- a/tests.sh
+++ b/tests.sh
@@ -105,7 +105,12 @@ function test_0014() {
     find_diff "$1" -writable
 }
 
-for i in {1..14}; do
+function test_0015() {
+    basic_structure "$1"
+    find_diff "$1" -empty
+}
+
+for i in {1..15}; do
     dir="$(mktemp -d "${TMPDIR:-/tmp}"/bfs.XXXXXXXXXX)"
     test="test_$(printf '%04d' $i)"
     "$test" "$dir"
-- 
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