vfs_vector: Add VectorVfsFile

Maps a vector into the VFS interface.

src/core/file_sys/vfs_vector.cpp

@@ -7,6 +7,57 @@
 #include "core/file_sys/vfs_vector.h"
 
 namespace FileSys {
+VectorVfsFile::VectorVfsFile(std::vector<u8> initial_data, std::string name, VirtualDir parent)
+    : data(std::move(initial_data)), name(std::move(name)), parent(std::move(parent)) {}
+
+std::string VectorVfsFile::GetName() const {
+    return name;
+}
+
+size_t VectorVfsFile::GetSize() const {
+    return data.size();
+}
+
+bool VectorVfsFile::Resize(size_t new_size) {
+    data.resize(new_size);
+    return data.size() == new_size;
+}
+
+std::shared_ptr<VfsDirectory> VectorVfsFile::GetContainingDirectory() const {
+    return parent;
+}
+
+bool VectorVfsFile::IsWritable() const {
+    return true;
+}
+
+bool VectorVfsFile::IsReadable() const {
+    return true;
+}
+
+size_t VectorVfsFile::Read(u8* data_, size_t length, size_t offset) const {
+    const auto read = std::min(length, data.size() - offset);
+    std::memcpy(data_, data.data() + offset, read);
+    return read;
+}
+
+size_t VectorVfsFile::Write(const u8* data_, size_t length, size_t offset) {
+    if (offset + length > data.size())
+        data.resize(offset + length);
+    const auto write = std::min(length, data.size() - offset);
+    std::memcpy(data.data(), data_, write);
+    return write;
+}
+
+bool VectorVfsFile::Rename(std::string_view name_) {
+    name = name_;
+    return true;
+}
+
+void VectorVfsFile::Assign(std::vector<u8> new_data) {
+    data = new_data;
+}
+
 VectorVfsDirectory::VectorVfsDirectory(std::vector<VirtualFile> files_,
                                        std::vector<VirtualDir> dirs_, std::string name_,
                                        VirtualDir parent_)

src/core/file_sys/vfs_vector.h

@@ -8,6 +8,30 @@
 
 namespace FileSys {
 
+// An implementation of VfsFile that is backed by a vector optionally supplied upon construction
+class VectorVfsFile : public VfsFile {
+public:
+    explicit VectorVfsFile(std::vector<u8> initial_data = {}, std::string name = "",
+                           VirtualDir parent = nullptr);
+
+    std::string GetName() const override;
+    size_t GetSize() const override;
+    bool Resize(size_t new_size) override;
+    std::shared_ptr<VfsDirectory> GetContainingDirectory() const override;
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    size_t Read(u8* data, size_t length, size_t offset) const override;
+    size_t Write(const u8* data, size_t length, size_t offset) override;
+    bool Rename(std::string_view name) override;
+
+    virtual void Assign(std::vector<u8> new_data);
+
+private:
+    std::vector<u8> data;
+    VirtualDir parent;
+    std::string name;
+};
+
 // An implementation of VfsDirectory that maintains two vectors for subdirectories and files.
 // Vector data is supplied upon construction.
 class VectorVfsDirectory : public VfsDirectory {