Deduplicate FSSourceAccessor and FSInputAccessor

src/libutil/source-accessor.cc

@@ -33,4 +33,53 @@ std::string SourceAccessor::showPath(const CanonPath & path)
     return path.abs();
 }
 
+std::string PosixSourceAccessor::readFile(const CanonPath & path)
+{
+    return nix::readFile(path.abs());
+}
+
+bool PosixSourceAccessor::pathExists(const CanonPath & path)
+{
+    return nix::pathExists(path.abs());
+}
+
+SourceAccessor::Stat PosixSourceAccessor::lstat(const CanonPath & path)
+{
+    auto st = nix::lstat(path.abs());
+    mtime = std::max(mtime, st.st_mtime);
+    return Stat {
+        .type =
+            S_ISREG(st.st_mode) ? tRegular :
+            S_ISDIR(st.st_mode) ? tDirectory :
+            S_ISLNK(st.st_mode) ? tSymlink :
+            tMisc,
+        .isExecutable = S_ISREG(st.st_mode) && st.st_mode & S_IXUSR
+    };
+}
+
+SourceAccessor::DirEntries PosixSourceAccessor::readDirectory(const CanonPath & path)
+{
+    DirEntries res;
+    for (auto & entry : nix::readDirectory(path.abs())) {
+        std::optional<Type> type;
+        switch (entry.type) {
+        case DT_REG: type = Type::tRegular; break;
+        case DT_LNK: type = Type::tSymlink; break;
+        case DT_DIR: type = Type::tDirectory; break;
+        }
+        res.emplace(entry.name, type);
+    }
+    return res;
+}
+
+std::string PosixSourceAccessor::readLink(const CanonPath & path)
+{
+    return nix::readLink(path.abs());
+}
+
+std::optional<CanonPath> PosixSourceAccessor::getPhysicalPath(const CanonPath & path)
+{
+    return path;
+}
+
 }