From aeff24ee344e5b9c4f2f9040a02320952e70ccd7 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Wed, 10 Feb 2016 22:15:41 -0500
Subject: Implement -samefile.

---
 bfs.h    |  7 +++++++
 eval.c   | 12 ++++++++++++
 parse.c  | 48 +++++++++++++++++++++++++++++++++++++++++-------
 tests.sh |  7 ++++++-
 4 files changed, 66 insertions(+), 8 deletions(-)

diff --git a/bfs.h b/bfs.h
index 24aeed8..c20fa17 100644
--- a/bfs.h
+++ b/bfs.h
@@ -15,6 +15,7 @@
 #include "color.h"
 #include <stdbool.h>
 #include <stddef.h>
+#include <sys/types.h>
 #include <time.h>
 
 /**
@@ -117,6 +118,11 @@ struct expr {
 	/** The optional time unit. */
 	enum timeunit timeunit;
 
+	/** Optional device number for a target file. */
+	dev_t dev;
+	/** Optional inode number for a target file. */
+	ino_t ino;
+
 	/** Optional integer data for this expression. */
 	int idata;
 
@@ -155,6 +161,7 @@ bool eval_empty(const struct expr *expr, struct eval_state *state);
 bool eval_hidden(const struct expr *expr, struct eval_state *state);
 bool eval_inum(const struct expr *expr, struct eval_state *state);
 bool eval_links(const struct expr *expr, struct eval_state *state);
+bool eval_samefile(const struct expr *expr, struct eval_state *state);
 bool eval_type(const struct expr *expr, struct eval_state *state);
 
 bool eval_name(const struct expr *expr, struct eval_state *state);
diff --git a/eval.c b/eval.c
index 543a98a..01da7a4 100644
--- a/eval.c
+++ b/eval.c
@@ -341,6 +341,18 @@ bool eval_quit(const struct expr *expr, struct eval_state *state) {
 	return true;
 }
 
+/**
+ * -samefile test.
+ */
+bool eval_samefile(const struct expr *expr, struct eval_state *state) {
+	const struct stat *statbuf = fill_statbuf(state);
+	if (!statbuf) {
+		return false;
+	}
+
+	return statbuf->st_dev == expr->dev && statbuf->st_ino == expr->ino;
+}
+
 /**
  * -type test.
  */
diff --git a/parse.c b/parse.c
index 4613aed..3498901 100644
--- a/parse.c
+++ b/parse.c
@@ -148,6 +148,21 @@ struct parser_state {
 	struct timespec now;
 };
 
+/**
+ * Invoke stat() on an argument.
+ */
+static int stat_arg(const struct parser_state *state, struct expr *expr, struct stat *sb) {
+	bool follow = state->cl->flags & BFTW_FOLLOW;
+	int flags = follow ? 0 : AT_SYMLINK_NOFOLLOW;
+
+	int ret = fstatat(AT_FDCWD, expr->sdata, sb, flags);
+	if (ret != 0) {
+		print_error(NULL, expr->sdata, errno);
+		free_expr(expr);
+	}
+	return ret;
+}
+
 /**
  * Parse the expression specified on the command line.
  */
@@ -344,13 +359,7 @@ static struct expr *parse_acnewer(struct parser_state *state, const char *option
 	}
 
 	struct stat sb;
-
-	bool follow = state->cl->flags & BFTW_FOLLOW;
-	int flags = follow ? 0 : AT_SYMLINK_NOFOLLOW;
-
-	if (fstatat(AT_FDCWD, expr->sdata, &sb, flags) != 0) {
-		print_error(NULL, expr->sdata, errno);
-		free_expr(expr);
+	if (stat_arg(state, expr, &sb) != 0) {
 		return NULL;
 	}
 
@@ -408,6 +417,26 @@ static struct expr *parse_depth(struct parser_state *state, const char *option,
 	return new_option(state, option);
 }
 
+/**
+ * Parse -samefile FILE.
+ */
+static struct expr *parse_samefile(struct parser_state *state, const char *option) {
+	struct expr *expr = parse_test_sdata(state, option, eval_samefile);
+	if (!expr) {
+		return NULL;
+	}
+
+	struct stat sb;
+	if (stat_arg(state, expr, &sb) != 0) {
+		return NULL;
+	}
+
+	expr->dev = sb.st_dev;
+	expr->ino = sb.st_ino;
+
+	return expr;
+}
+
 /**
  * Parse -type [bcdpfls].
  */
@@ -619,6 +648,11 @@ static struct expr *parse_literal(struct parser_state *state) {
 		}
 		break;
 
+	case 's':
+		if (strcmp(arg, "-samefile") == 0) {
+			return parse_samefile(state, arg);
+		}
+
 	case 't':
 		if (strcmp(arg, "-true") == 0) {
 			return &expr_true;
diff --git a/tests.sh b/tests.sh
index 8c8c347..f869acc 100755
--- a/tests.sh
+++ b/tests.sh
@@ -189,7 +189,12 @@ function test_0027() {
     find_diff -L "$1" -depth 2>/dev/null
 }
 
-for i in {1..27}; do
+function test_0028() {
+    links_structure "$1"
+    find_diff "$1" -samefile "$1/a"
+}
+
+for i in {1..28}; do
     dir="$(mktemp -d "${TMPDIR:-/tmp}"/bfs.XXXXXXXXXX)"
     test="test_$(printf '%04d' $i)"
     "$test" "$dir"
-- 
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