add io::MemoryDevice

src/io/devices/MemoryDevice.hpp

@@ -0,0 +1,70 @@
+#pragma once
+
+#include "Device.hpp"
+#include "util/Buffer.hpp"
+
+#include <vector>
+#include <variant>
+#include <optional>
+#include <unordered_map>
+
+namespace io {
+    /// @brief In-memory filesystem device
+    class MemoryDevice : public Device {
+        enum class NodeType {
+            DIR, FILE
+        };
+
+        struct File {
+            util::Buffer<char> content;
+        };
+
+        struct Dir {
+            std::vector<std::string> content;
+        };
+
+        struct Node {
+            std::variant<Dir, File> data;
+
+            NodeType type() const {
+                return std::visit([](auto&& arg) -> NodeType {
+                    using T = std::decay_t<decltype(arg)>;
+                    if constexpr (std::is_same_v<T, Dir>) return NodeType::DIR;
+                    else if constexpr (std::is_same_v<T, File>) return NodeType::FILE;
+                }, data);
+            }
+
+            template <typename T>
+            bool holds_alternative() const {
+                return std::holds_alternative<T>(data);
+            }
+
+            template <typename T>
+            T* get_if() {
+                return std::get_if<T>(&data);
+            }
+        };
+    public:
+        MemoryDevice();
+
+        std::filesystem::path resolve(std::string_view path) override;
+        std::unique_ptr<std::ostream> write(std::string_view path) override;
+        std::unique_ptr<std::istream> read(std::string_view path) override;
+        size_t size(std::string_view path) override;
+        file_time_type lastWriteTime(std::string_view path) override;
+        bool exists(std::string_view path) override;
+        bool isdir(std::string_view path) override;
+        bool isfile(std::string_view path) override;
+        bool mkdir(std::string_view path) override;
+        bool mkdirs(std::string_view path) override;
+        bool remove(std::string_view path) override;
+        uint64_t removeAll(std::string_view path) override;
+        std::unique_ptr<PathsGenerator> list(std::string_view path) override;
+    private:
+        std::unordered_map<std::string, Node> nodes;
+
+        Node* createFile(std::string path, util::Buffer<char>&& content);
+        Dir* createDir(std::string path);
+        Dir* getDir(std::string_view path);
+    };
+}