Test getting a file path with procfs and devfs

Author: bugdea1er

.github/workflows/posix.yml

@@ -2,7 +2,7 @@
 name: posix
 "on":
   push:
-    branches: [main]
+    branches: [main, file-path]
   pull_request:
 
 env:

include/tmp/file

@@ -75,6 +75,14 @@ public:
   /// @returns The underlying implementation-defined handle
   native_handle_type native_handle() const noexcept;
 
+  /// Returns the managed path
+  /// @returns The full path this entry manages
+  operator const std::filesystem::path&() const noexcept;
+
+  /// Returns the managed path
+  /// @returns The full path this entry manages
+  const std::filesystem::path& path() const noexcept;
+
   /// Moves the managed file to a given target, releasing
   /// ownership of the managed file; behaves like `std::filesystem::rename`
   /// even when moving between filesystems

src/file.cpp

@@ -202,6 +202,18 @@ file::native_handle_type file::native_handle() const noexcept {
 #endif
 }
 
+file::operator const fs::path&() const noexcept {
+#ifdef __linux__
+  return fs::path("/proc/self/fd") / std::to_string(native_handle());
+#else
+  return fs::path("/dev/fd") / std::to_string(native_handle());
+#endif
+}
+
+const fs::path& file::path() const noexcept {
+  return *this;
+}
+
 void file::move(const fs::path& to) {
   // TODO: I couldn't figure out how to create a hard link to a file without
   // other hard links, so I just copy it even within the same file system

tests/file.cpp

@@ -87,6 +87,14 @@ TEST(file, create) {
   EXPECT_EQ(file_stat.st_mode & S_IFMT, S_IFREG);    // Is a regular file
   EXPECT_EQ(file_stat.st_nlink, 0);                  // Has no hardlinks
 #endif
+
+  EXPECT_TRUE(fs::exists(tmpfile));
+  std::ofstream(tmpfile.path(), std::ios::binary) << "Hello, world!";
+
+  tmpfile.seekp(0, std::ios::beg);
+
+  std::string content = std::string(std::istreambuf_iterator(tmpfile), {});
+  EXPECT_EQ(content, "Hello, world!");
 }
 
 /// Tests multiple file creation