Move ReadLink from files.cpp to cuttlefish/posix

Assisted-by: Jetski:Gemini Next

Author: Databean

base/cvd/cuttlefish/common/libs/utils/BUILD.bazel

@@ -258,6 +258,7 @@ cf_cc_library(
     deps = [
         "//cuttlefish/common/libs/fs",
         "//cuttlefish/common/libs/utils:files",
+        "//cuttlefish/posix:readlink",
         "//cuttlefish/result",
         "//libbase",
         "@abseil-cpp//absl/log",

base/cvd/cuttlefish/common/libs/utils/files.cpp

@@ -509,20 +509,6 @@ Result<std::string> ReadFileContents(const std::string& filepath) {
              file->StrError());
   return file_content;
 }
-
-Result<std::string> ReadLink(const std::string& path) {
-  std::vector<char> buf(4096);
-  while (true) {
-    ssize_t size = readlink(path.c_str(), buf.data(), buf.size());
-    CF_EXPECTF(size != -1, "readlink(\"{}\") failed: {}", path,
-               StrError(errno));
-    if (static_cast<size_t>(size) < buf.size()) {
-      return std::string(buf.data(), size);
-    }
-    buf.resize(buf.size() * 2);
-  }
-}
-
 Result<void> WriteNewFile(const std::string& filepath, std::string_view content,
                           mode_t mode) {
   CF_EXPECTF(!FileExists(filepath), "File already exists: {}", filepath);

base/cvd/cuttlefish/common/libs/utils/files.h

@@ -72,7 +72,6 @@ Result<std::string> RenameFile(const std::string& current_filepath,
                                const std::string& target_filepath);
 std::string ReadFile(const std::string& file);
 Result<std::string> ReadFileContents(const std::string& filepath);
-Result<std::string> ReadLink(const std::string& path);
 Result<void> WriteNewFile(const std::string& filepath, std::string_view content,
                           mode_t mode = S_IRWXU | S_IRGRP | S_IROTH);
 bool MakeFileExecutable(const std::string& path);

base/cvd/cuttlefish/common/libs/utils/proc_file_utils.cpp

@@ -37,6 +37,7 @@
 #include "cuttlefish/common/libs/fs/shared_buf.h"
 #include "cuttlefish/common/libs/fs/shared_fd.h"
 #include "cuttlefish/common/libs/utils/files.h"
+#include "cuttlefish/posix/readlink.h"
 #include "cuttlefish/result/result.h"
 
 namespace cuttlefish {

base/cvd/cuttlefish/host/libs/command_util/BUILD.bazel

@@ -37,6 +37,7 @@ cf_cc_library(
         "//cuttlefish/common/libs/utils:json",
         "//cuttlefish/host/libs/config:config_instance_derived",
         "//cuttlefish/host/libs/config:cuttlefish_config",
+        "//cuttlefish/posix:readlink",
         "//cuttlefish/posix:strerror",
         "//cuttlefish/posix:symlink",
         "//cuttlefish/result",

base/cvd/cuttlefish/host/libs/command_util/snapshot_utils.cc

@@ -24,14 +24,15 @@
 #include <string>
 #include <unordered_map>
 
-#include <android-base/file.h>
-#include "absl/strings/strip.h"
 #include "absl/log/log.h"
+#include "absl/strings/strip.h"
+#include "android-base/file.h"
 
 #include "cuttlefish/common/libs/fs/shared_fd.h"
 #include "cuttlefish/common/libs/utils/environment.h"
 #include "cuttlefish/common/libs/utils/files.h"
 #include "cuttlefish/common/libs/utils/json.h"
+#include "cuttlefish/posix/readlink.h"
 #include "cuttlefish/posix/symlink.h"
 #include "cuttlefish/result/result.h"
 

base/cvd/cuttlefish/posix/BUILD.bazel

@@ -32,3 +32,13 @@ cf_cc_library(
         "//cuttlefish/result",
     ],
 )
+
+cf_cc_library(
+    name = "readlink",
+    srcs = ["readlink.cc"],
+    hdrs = ["readlink.h"],
+    deps = [
+        "//cuttlefish/posix:strerror",
+        "//cuttlefish/result",
+    ],
+)

base/cvd/cuttlefish/posix/readlink.cc

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2026 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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 "cuttlefish/posix/readlink.h"
+
+#include <errno.h>
+#include <unistd.h>
+
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include "cuttlefish/posix/strerror.h"
+#include "cuttlefish/result/result.h"
+
+namespace cuttlefish {
+
+Result<std::string> ReadLink(const char* path) {
+  std::vector<char> buf(4096);
+  while (true) {
+    ssize_t size = readlink(path, buf.data(), buf.size());
+    CF_EXPECTF(size != -1, "readlink('{}') failed: {}", path, StrError(errno));
+    if (static_cast<size_t>(size) < buf.size()) {
+      return std::string(buf.data(), size);
+    }
+    buf.resize(buf.size() * 2);
+  }
+}
+
+Result<std::string> ReadLink(const std::string& path) {
+  return ReadLink(path.c_str());
+}
+
+Result<std::string> ReadLink(std::string_view path) {
+  return ReadLink(std::string(path));
+}
+
+}  // namespace cuttlefish

base/cvd/cuttlefish/posix/readlink.h

@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2026 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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.
+ */
+#pragma once
+
+#include <string>
+#include <string_view>
+
+#include "cuttlefish/result/result.h"
+
+namespace cuttlefish {
+
+// Wrapper for readlink(2).
+Result<std::string> ReadLink(const char* path);
+Result<std::string> ReadLink(const std::string& path);
+Result<std::string> ReadLink(std::string_view path);
+
+}  // namespace cuttlefish