From ab00092c6c5fa79fe40403db25d0f3e8123c61e6 Mon Sep 17 00:00:00 2001
From: Francis Tsui <ftsui@google.com>
Date: Thu, 3 Oct 2024 12:35:56 -0700
Subject: [PATCH] Create hard link for latest log files.

PiperOrigin-RevId: 681986911
---
 Package.swift               |  1 +
 internal/base/BUILD         | 24 +++++++++++--------
 internal/base/files.cc      | 10 ++++++++
 internal/base/files.h       |  5 ++++
 internal/base/files_test.cc | 48 +++++++++++++++++++++++++++++++++++++
 5 files changed, 78 insertions(+), 10 deletions(-)
 create mode 100644 internal/base/files_test.cc

diff --git a/Package.swift b/Package.swift
index 12f8cec2..8d06fd0d 100644
--- a/Package.swift
+++ b/Package.swift
@@ -493,6 +493,7 @@ let package = Package(
         "connections/status_test.cc",
         "connections/payload_test.cc",
         "internal/base/bluetooth_address_test.cc",
+        "internal/base/files_test.cc",
         "internal/crypto/ed25519_unittest.cc",
         "internal/crypto_cros/aead_unittest.cc",
         "internal/crypto_cros/ec_private_key_unittest.cc",
diff --git a/internal/base/BUILD b/internal/base/BUILD
index 5077a12c..689613f9 100644
--- a/internal/base/BUILD
+++ b/internal/base/BUILD
@@ -21,9 +21,6 @@ cc_library(
     hdrs = [
         "observer_list.h",
     ],
-    copts = [
-        "-Ithird_party",
-    ],
     visibility = [
         "//fastpair:__subpackages__",
         "//internal/account:__subpackages__",
@@ -46,9 +43,6 @@ cc_library(
     hdrs = [
         "bluetooth_address.h",
     ],
-    copts = [
-        "-Ithird_party",
-    ],
     visibility = [
         "//fastpair:__subpackages__",
         "//internal:__subpackages__",
@@ -76,10 +70,6 @@ cc_test(
     srcs = [
         "bluetooth_address_test.cc",
     ],
-    copts = [
-        "-Ithird_party",
-    ],
-    shard_count = 8,
     deps = [
         ":bluetooth_address",
         "@com_github_protobuf_matchers//protobuf-matchers",
@@ -88,3 +78,17 @@ cc_test(
         "@com_google_googletest//:gtest_main",
     ],
 )
+
+cc_test(
+    name = "files_test",
+    size = "small",
+    timeout = "short",
+    srcs = [
+        "files_test.cc",
+    ],
+    deps = [
+        ":files",
+        "@com_github_protobuf_matchers//protobuf-matchers",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
diff --git a/internal/base/files.cc b/internal/base/files.cc
index f2056fb8..c3e3b12a 100644
--- a/internal/base/files.cc
+++ b/internal/base/files.cc
@@ -95,4 +95,14 @@ bool CreateDirectories(const std::filesystem::path& path) {
   return true;
 }
 
+bool CreateHardLink(const std::filesystem::path& target,
+                    const std::filesystem::path& link_path) {
+  std::error_code error_code;
+  std::filesystem::create_hard_link(target, link_path, error_code);
+  if (error_code) {
+    return false;
+  }
+  return true;
+}
+
 }  // namespace nearby::sharing
diff --git a/internal/base/files.h b/internal/base/files.h
index f6c4ff5c..501e8752 100644
--- a/internal/base/files.h
+++ b/internal/base/files.h
@@ -51,6 +51,11 @@ bool Rename(const std::filesystem::path& old_path,
 // Returns true on success.
 bool CreateDirectories(const std::filesystem::path& path);
 
+// Creates a hard link to target at link_path.
+// Returns true on success.
+bool CreateHardLink(const std::filesystem::path& target,
+                    const std::filesystem::path& link_path);
+
 }  // namespace nearby::sharing
 
 #endif  // THIRD_PARTY_NEARBY_INTERNAL_BASE_FILES_H_
diff --git a/internal/base/files_test.cc b/internal/base/files_test.cc
new file mode 100644
index 00000000..7a8e1530
--- /dev/null
+++ b/internal/base/files_test.cc
@@ -0,0 +1,48 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "internal/base/files.h"
+
+#include <cstdint>
+#include <filesystem>  // NOLINT
+#include <fstream>
+#include <ios>
+#include <optional>
+
+#include "gtest/gtest.h"
+
+namespace nearby::sharing {
+namespace {
+
+TEST(FilesTest, CreateHardLinkSuccess) {
+  std::filesystem::path temp_dir = testing::TempDir();
+  std::filesystem::path target = temp_dir / "target";
+  RemoveFile(target);
+  std::ofstream ofstream(target, std::ios::app);
+  ASSERT_EQ(ofstream.rdstate(), std::ios_base::goodbit);
+  ofstream << "Hello world";
+  ofstream.flush();
+  std::optional<uintmax_t> size = GetFileSize(target);
+  ASSERT_TRUE(size.has_value());
+  EXPECT_EQ(size.value(), 11);
+  std::filesystem::path link_path = temp_dir / "link_path";
+  EXPECT_TRUE(CreateHardLink(target, link_path));
+  EXPECT_TRUE(FileExists(link_path));
+  EXPECT_EQ(GetFileSize(link_path), 11);
+  RemoveFile(link_path);
+  RemoveFile(target);
+}
+
+}  // namespace
+}  // namespace nearby::sharing