add io::MemoryDevice

src/io/devices/MemoryDevice.cpp

@@ -0,0 +1,210 @@
+#include "MemoryDevice.hpp"
+
+#include "../memory_istream.hpp"
+#include "../memory_ostream.hpp"
+#include "../finalizing_ostream.hpp"
+
+#include <algorithm>
+
+io::MemoryDevice::MemoryDevice() {}
+
+std::filesystem::path io::MemoryDevice::resolve(std::string_view path) {
+    throw std::runtime_error("unable to resolve filesystem path");
+}
+
+std::unique_ptr<std::ostream> io::MemoryDevice::write(std::string_view path) {
+    std::string filePath = std::string(path);
+    return std::make_unique<finalizing_ostream>(
+        std::make_unique<memory_ostream>(),
+        [this, filePath](auto ostream) {
+            auto& memoryStream = dynamic_cast<memory_ostream&>(*ostream);
+            createFile(std::move(filePath), memoryStream.release());
+        }
+    );
+}
+
+std::unique_ptr<std::istream> io::MemoryDevice::read(std::string_view path) {
+    const auto& found = nodes.find(std::string(path));
+    if (found == nodes.end()) {
+        return nullptr;
+    }
+    auto& node = found->second;
+    if (auto file = node.get_if<File>()) {
+        if (file->content != nullptr) {
+            return std::make_unique<memory_view_istream>(file->content);
+        }
+    }
+    return nullptr;
+}
+
+size_t io::MemoryDevice::size(std::string_view path) {
+    const auto& found = nodes.find(std::string(path));
+    if (found == nodes.end()) {
+        return 0;
+    }
+    return std::visit([](auto&& arg) -> size_t {
+        using T = std::decay_t<decltype(arg)>;
+        if constexpr (std::is_same_v<T, File>) {
+            return arg.content.size();
+        } else if constexpr (std::is_same_v<T, Dir>) {
+            return arg.content.size();
+        } else {
+            return 0;
+        }
+    }, found->second.data);
+}
+
+io::file_time_type io::MemoryDevice::lastWriteTime(std::string_view path) {
+    return file_time_type::min();
+}
+
+bool io::MemoryDevice::exists(std::string_view path) {
+    return nodes.find(std::string(path)) != nodes.end();
+}
+
+bool io::MemoryDevice::isdir(std::string_view path) {
+    const auto& found = nodes.find(std::string(path));
+    if (found == nodes.end()) {
+        return false;
+    }
+    return found->second.holds_alternative<Dir>();
+}
+
+bool io::MemoryDevice::isfile(std::string_view path)  {
+    const auto& found = nodes.find(std::string(path));
+    if (found == nodes.end()) {
+        return false;
+    }
+    return found->second.holds_alternative<File>();
+}
+
+bool io::MemoryDevice::mkdir(std::string_view path) {
+    return createDir(std::string(path)) != nullptr;
+}
+
+bool io::MemoryDevice::mkdirs(std::string_view path) {
+    io::path dirPath = std::string(path);
+    std::vector<std::string> parts;
+    while (!dirPath.pathPart().empty()) {
+        parts.push_back(dirPath.name());
+        dirPath = dirPath.parent();
+    }
+    for (int i = parts.size() - 1; i >= 0; i--) {
+        dirPath = dirPath / parts[i];
+        createDir(dirPath.string());
+    }
+    return true;
+}
+
+bool io::MemoryDevice::remove(std::string_view path) {
+    std::string pathString = std::string(path);
+    const auto& found = nodes.find(pathString);
+    if (found == nodes.end()) {
+        return false;
+    }
+    if (found->second.holds_alternative<Dir>()) {
+        const auto& dir = found->second.get_if<Dir>();
+        if (!dir->content.empty()) {
+            return false;
+        }
+    }
+    io::path filePath = pathString;
+    io::path parentPath = filePath.parent();
+    auto parentDir = getDir(parentPath.string());
+    if (parentDir) {
+        auto& content = parentDir->content;
+        content.erase(
+            std::remove(content.begin(), content.end(), filePath.name()),
+            content.end()
+        );
+    }
+    nodes.erase(found);
+    return true;
+}
+
+uint64_t io::MemoryDevice::removeAll(std::string_view path) {
+    std::string pathString = std::string(path);
+    const auto& found = nodes.find(pathString);
+    if (found == nodes.end()) {
+        return 0;
+    }
+    io::path filePath = pathString;
+
+    uint64_t count = 0;
+    if (found->second.holds_alternative<Dir>()) {
+        auto dir = found->second.get_if<Dir>();
+        for (const auto& name : dir->content) {
+            io::path subPath = filePath / name;
+            count += removeAll(subPath.string());
+        }
+    }
+    if (remove(pathString)) {
+        count++;
+    }
+    return count;
+}
+
+namespace {
+    struct MemoryPathsGenerator : public io::PathsGenerator {
+        std::vector<std::string> entries;
+        size_t index = 0;
+
+        MemoryPathsGenerator(std::vector<std::string>&& entries)
+            : entries(std::move(entries)) {}
+
+        bool next(io::path& outPath) override {
+            if (index >= entries.size()) {
+                return false;
+            }
+            outPath = entries[index++];
+            return true;
+        }
+    };
+}
+
+std::unique_ptr<io::PathsGenerator> io::MemoryDevice::list(std::string_view path) {
+    auto dir = getDir(path);
+    if (!dir) {
+        return nullptr;
+    }
+    return std::make_unique<MemoryPathsGenerator>(
+        std::vector<std::string>(dir->content)
+    );
+}
+
+io::MemoryDevice::Dir* io::MemoryDevice::createDir(std::string path) {
+    io::path filePath = path;
+    io::path parent = filePath.parent();
+    auto parentDir = getDir(parent.string());
+    if (!parentDir) {
+        return nullptr;
+    }
+    parentDir->content.push_back(filePath.name());
+    auto& node = nodes[std::move(path)];
+    node.data = Dir {};
+    return node.get_if<Dir>();
+}
+
+io::MemoryDevice::Node* io::MemoryDevice::createFile(
+    std::string path, util::Buffer<char>&& content
+) {
+    io::path filePath = path;
+    io::path parent = filePath.parent();
+    auto dir = getDir(parent.string());
+    if (!dir) {
+        return nullptr;
+    }
+    dir->content.push_back(filePath.name());
+    auto& node = nodes[std::move(path)];
+    node.data = File {std::move(content)};
+    return &node;
+}
+
+io::MemoryDevice::Dir* io::MemoryDevice::getDir(std::string_view path) {
+    const auto& found = nodes.find(std::string(path));
+    if (found == nodes.end()) {
+        return nullptr;
+    }
+    auto& node = found->second;
+    return node.get_if<Dir>();
+}

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);
+    };
+}