Get refcode on MacOS from xattr.

components/brave_referrals/browser/BUILD.gn

@@ -29,6 +29,13 @@ static_library("browser") {
     "//services/network/public/cpp",
   ]
 
+  if (is_mac) {
+    sources += [
+      "file_extended_attribute.cc",
+      "file_extended_attribute.h",
+    ]
+  }
+
   if (is_android) {
     sources += [
       "android_brave_referrer.cc",
@@ -47,3 +54,19 @@ if (is_android) {
     sources = [ "//brave/android/java/org/chromium/chrome/browser/util/BraveReferrer.java" ]
   }
 }
+
+source_set("unit_tests") {
+  testonly = true
+  sources = []
+  deps = []
+
+  if (is_mac) {
+    sources += [ "file_extended_attribute_unittest.cc" ]
+    deps += [
+      ":browser",
+      "//base",
+      "//base/test:test_support",
+      "//testing/gtest",
+    ]
+  }
+}

components/brave_referrals/browser/brave_referrals_service.cc

@@ -15,6 +15,7 @@
 #include "base/functional/callback_helpers.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
+#include "base/logging.h"
 #include "base/path_service.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
@@ -26,6 +27,7 @@
 #include "brave/components/constants/network_constants.h"
 #include "brave/components/constants/pref_names.h"
 #include "brave_base/random.h"
+#include "build/build_config.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
 #include "components/url_matcher/url_matcher.h"
@@ -40,6 +42,11 @@
 #include "services/network/public/mojom/fetch_api.mojom-shared.h"
 #include "services/network/public/mojom/url_response_head.mojom.h"
 
+#if BUILDFLAG(IS_MAC)
+#include "base/apple/bundle_locations.h"
+#include "brave/components/brave_referrals/browser/file_extended_attribute.h"
+#endif  // BUILDFLAG(IS_MAC)
+
 // Perform finalization checks once a day.
 const int kFinalizationChecksFrequency = 60 * 60 * 24;
 
@@ -125,9 +132,46 @@ void DeletePromoCodeFile(const base::FilePath& promo_code_file) {
   }
 }
 
+#if BUILDFLAG(IS_MAC)
+std::string ReadPromoCodeFromXattr() {
+  static constexpr char kRefCodeAttr[] = "com.brave.refcode";
+  base::FilePath bundle_path = base::apple::OuterBundlePath();
+  std::vector<char> value;
+  int result_errno =
+      brave::GetFileExtendedAttribute(bundle_path, kRefCodeAttr, &value);
+  if (result_errno == ENOATTR) {
+    VLOG(0) << "Could not get promo code from " << bundle_path
+            << ". The extended attribute " << kRefCodeAttr << " was not found.";
+  } else if (result_errno != 0) {
+    VLOG(0) << "Could not get promo code from " << bundle_path
+            << ". An error occurred getting value for attribute "
+            << kRefCodeAttr << ". Error code: " << result_errno << ".";
+  } else {
+    std::string promo_code(value.begin(), value.end());
+    base::TrimWhitespaceASCII(promo_code, base::TRIM_ALL, &promo_code);
+    if (promo_code.empty()) {
+      VLOG(0) << "Promo code value from " << bundle_path
+              << "'s extended attribute " << kRefCodeAttr << " is empty.";
+    } else {
+      DVLOG(1) << "Promo code from " << kRefCodeAttr << ": " << promo_code;
+      return promo_code;
+    }
+  }
+
+  return "";
+}
+#endif  // BUILDFLAG(IS_MAC)
+
 std::string ReadPromoCode(const base::FilePath& promo_code_file) {
   std::string promo_code;
 
+#if BUILDFLAG(IS_MAC)
+  promo_code = ReadPromoCodeFromXattr();
+  if (!promo_code.empty()) {
+    return promo_code;
+  }
+#endif  // BUILDFLAG(IS_MAC)
+
   if (!base::PathExists(promo_code_file)) {
     return kDefaultPromoCode;
   }

components/brave_referrals/browser/file_extended_attribute.cc

@@ -0,0 +1,39 @@
+/* Copyright (c) 2023 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include "brave/components/brave_referrals/browser/file_extended_attribute.h"
+
+#include <sys/xattr.h>
+
+#include "base/logging.h"
+
+namespace brave {
+
+int GetFileExtendedAttribute(const base::FilePath& path,
+                             const char* name,
+                             std::vector<char>* value) {
+  // Pass nullptr for value to retrieve the length needed.
+  ssize_t expected_length =
+      getxattr(path.value().c_str(), name, /*value=*/nullptr,
+               /*size =*/0, /*position=*/0, /*options=*/0);
+  if (expected_length < 0) {
+    return errno;
+  }
+
+  value->resize(expected_length);
+  ssize_t length = getxattr(path.value().c_str(), name, value->data(),
+                            expected_length, /*position=*/0,
+                            /*options=*/0);
+  if (length != expected_length) {
+    VLOG(0) << "Failed to retrieve extended attribute " << name << " from file "
+            << path << ". The expected data length (" << expected_length
+            << ") and actual data length (" << length << ") do not match.";
+    return ENODATA;
+  }
+
+  return 0;
+}
+
+}  // namespace brave

components/brave_referrals/browser/file_extended_attribute.h

@@ -0,0 +1,28 @@
+/* Copyright (c) 2023 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#ifndef BRAVE_COMPONENTS_BRAVE_REFERRALS_BROWSER_FILE_EXTENDED_ATTRIBUTE_H_
+#define BRAVE_COMPONENTS_BRAVE_REFERRALS_BROWSER_FILE_EXTENDED_ATTRIBUTE_H_
+
+#include <vector>
+
+#include "base/files/file_path.h"
+
+namespace brave {
+
+// Extracts the value of an extended file attribute specified by |name| from the
+// file specified by the |path|. The result is placed in the |value|. On
+// success returns 0. Otherwise, returns ERRNO value. Error values of
+// interest:
+// ENOATTR - the attribute with the given |name| was not found.
+// ENOTSUP - the file system doesn't support (or disabled) extended attributes.
+// ENODATA - the value could not be retrieved.
+int GetFileExtendedAttribute(const base::FilePath& path,
+                             const char* name,
+                             std::vector<char>* value);
+
+}  // namespace brave
+
+#endif  // BRAVE_COMPONENTS_BRAVE_REFERRALS_BROWSER_FILE_EXTENDED_ATTRIBUTE_H_

components/brave_referrals/browser/file_extended_attribute_unittest.cc

@@ -0,0 +1,60 @@
+/* Copyright (c) 2023 The Brave Authors. All rights reserved.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#include <sys/xattr.h>
+#include <string>
+#include <vector>
+
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/files/scoped_temp_dir.h"
+#include "brave/components/brave_referrals/browser/file_extended_attribute.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+constexpr char kXattrName[] = "com.brave.refcode";
+constexpr char kXattrValue[] = "0xDEADFACE";
+}  // namespace
+
+class BraveFileExtendedAttributeTest : public testing::Test {
+ public:
+  BraveFileExtendedAttributeTest() = default;
+  ~BraveFileExtendedAttributeTest() override = default;
+
+  void SetUp() override {
+    ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
+    ASSERT_TRUE(
+        base::CreateTemporaryFileInDir(temp_dir_.GetPath(), &test_file_path_));
+    ASSERT_EQ(0,
+              setxattr(test_file_path_.value().c_str(), kXattrName, kXattrValue,
+                       strlen(kXattrValue), /*position=*/0, /*options=*/0));
+  }
+
+  void TearDown() override { base::DeletePathRecursively(temp_dir_.GetPath()); }
+
+  const base::FilePath& test_file_path() { return test_file_path_; }
+
+ private:
+  base::ScopedTempDir temp_dir_;
+  base::FilePath test_file_path_;
+};
+
+TEST_F(BraveFileExtendedAttributeTest, GetPromoCodeAttribute) {
+  std::vector<char> value;
+  // Test file has this extended attribute
+  int result_errno =
+      brave::GetFileExtendedAttribute(test_file_path(), kXattrName, &value);
+  EXPECT_EQ(0, result_errno);
+  std::string xattr_value(value.begin(), value.end());
+  EXPECT_EQ(kXattrValue, xattr_value);
+}
+
+TEST_F(BraveFileExtendedAttributeTest, GetNonexistentAttribute) {
+  std::vector<char> value;
+  // Test file does NOT have this extended attribute
+  int result_errno = brave::GetFileExtendedAttribute(
+      test_file_path(), "com.brave.MadSheep", &value);
+  EXPECT_EQ(ENOATTR, result_errno);
+}

test/BUILD.gn

@@ -206,6 +206,7 @@ test("brave_unit_tests") {
     "//brave/components/brave_news/browser/test:brave_news_unit_tests",
     "//brave/components/brave_perf_predictor/browser",
     "//brave/components/brave_private_cdn",
+    "//brave/components/brave_referrals/browser:unit_tests",
     "//brave/components/brave_rewards/common",
     "//brave/components/brave_rewards/common:features",
     "//brave/components/brave_rewards/core/test",