add simple unit test for creating hard links

src/file.cpp

@@ -493,7 +493,7 @@ namespace libtorrent
 		std::string n_exist = convert_to_native(file);
 		std::string n_link = convert_to_native(link);
 #endif
-		BOOL ret = CreateHardLink(n_link.c_str(), n_exist.c_str(), NULL);
+		BOOL ret = CreateHardLink_(n_link.c_str(), n_exist.c_str(), NULL);
 		if (ret)
 		{
 			ec.clear();
@@ -503,11 +503,16 @@ namespace libtorrent
 		// something failed. Does the filesystem not support hard links?
 		// TODO: 3 find out what error code is reported when the filesystem
 		// does not support hard links.
+		DWORD error = GetLastError();
+		if (error != ERROR_NOT_SUPPORTED || error != ERROR_ACCESS_DENIED)
+		{
+			// it's possible CreateHardLink will copy the file internally too,
+			// if the filesystem does not support it.
+			ec.assign(GetLastError(), system_category());
+			return;
+		}
 
-		// it's possible CreateHardLink will copy the file internally too,
+		// fall back to making a copy
-		// if the filesystem does not support it.
-		ec.assign(GetLastError(), system_category());
-		return;
 
 #else
 
@@ -532,6 +537,9 @@ namespace libtorrent
 			ec.assign(errno, generic_category());
 			return;
 		}
+
+		// fall back to making a copy
+
 #endif
 
 		// if we get here, we should copy the file

test/test_dht.cpp

@@ -452,7 +452,7 @@ dht_settings test_settings()
 }
 
 // TODO: test obfuscated_get_peers
-// TODO: 3 split this test up into smaller test cases
+// TODO: 2 split this test up into smaller test cases
 TORRENT_TEST(dht)
 {
 	dht_settings sett = test_settings();

test/test_file.cpp

@@ -290,7 +290,7 @@ TORRENT_TEST(file)
 #endif
 	if (ec)
 		fprintf(stderr, "open failed: [%s] %s\n", ec.category().name(), ec.message().c_str());
-	TEST_CHECK(!ec);
+	TEST_EQUAL(ec, error_code());
 	if (ec) fprintf(stderr, "%s\n", ec.message().c_str());
 	file::iovec_t b = {(void*)"test", 4};
 	TEST_EQUAL(f.writev(0, &b, 1, ec), 4);
@@ -303,8 +303,60 @@ TORRENT_TEST(file)
 	TEST_EQUAL(f.readv(0, &b, 1, ec), 4);
 	if (ec)
 		fprintf(stderr, "readv failed: [%s] %s\n", ec.category().name(), ec.message().c_str());
-	TEST_CHECK(!ec);
+	TEST_EQUAL(ec, error_code());
 	TEST_CHECK(strcmp(test_buf, "test") == 0);
 	f.close();
 }
 
+TORRENT_TEST(hard_link)
+{
+	// try to create a hard link to see what happens
+	// first create a regular file to then add another link to.
+
+	// create a file, write some stuff to it, create a hard link to that file,
+	// read that file and assert we get the same stuff we wrote to the first file
+	error_code ec;
+	file f;
+	TEST_CHECK(f.open("original_file", file::read_write, ec));
+	if (ec)
+		fprintf(stderr, "open failed: [%s] %s\n", ec.category().name(), ec.message().c_str());
+	TEST_EQUAL(ec, error_code());
+
+	file::iovec_t b = {(void*)"abcdefghijklmnopqrstuvwxyz", 26};
+	TEST_EQUAL(f.writev(0, &b, 1, ec), 26);
+	if (ec)
+		fprintf(stderr, "writev failed: [%s] %s\n", ec.category().name(), ec.message().c_str());
+	TEST_EQUAL(ec, error_code());
+	f.close();
+
+	hard_link("original_file", "second_link", ec);
+
+	if (ec)
+		fprintf(stderr, "hard_link failed: [%s] %s\n", ec.category().name(), ec.message().c_str());
+	TEST_EQUAL(ec, error_code());
+
+
+	TEST_CHECK(f.open("second_link", file::read_write, ec));
+	if (ec)
+		fprintf(stderr, "open failed: [%s] %s\n", ec.category().name(), ec.message().c_str());
+	TEST_EQUAL(ec, error_code());
+
+	char test_buf[27] = {0};
+	b.iov_base = test_buf;
+	b.iov_len = 27;
+	TEST_EQUAL(f.readv(0, &b, 1, ec), 26);
+	if (ec)
+		fprintf(stderr, "readv failed: [%s] %s\n", ec.category().name(), ec.message().c_str());
+	TEST_EQUAL(ec, error_code());
+	TEST_CHECK(strcmp(test_buf, "abcdefghijklmnopqrstuvwxyz") == 0);
+	f.close();
+
+	remove("original_file", ec);
+	if (ec)
+		fprintf(stderr, "remove failed: [%s] %s\n", ec.category().name(), ec.message().c_str());
+
+	remove("second_link", ec);
+	if (ec)
+		fprintf(stderr, "remove failed: [%s] %s\n", ec.category().name(), ec.message().c_str());
+}
+