Virtual Filesystem 2: Electric Boogaloo (#676)

* Virtual Filesystem

* Fix delete bug and documentate

* Review fixes + other stuff

* Fix puyo regression

1 files changed, 237 insertions, 0 deletions

diff --git a/src/core/file_sys/vfs.h b/src/core/file_sys/vfs.h
new file mode 100644
index 000000000..a5213e0cc
--- /dev/null
+++ b/src/core/file_sys/vfs.h
@@ -0,0 +1,237 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <string>
+#include <type_traits>
+#include <vector>
+#include "boost/optional.hpp"
+#include "common/common_types.h"
+#include "common/file_util.h"
+
+namespace FileSys {
+struct VfsFile;
+struct VfsDirectory;
+
+// Convenience typedefs to use VfsDirectory and VfsFile
+using VirtualDir = std::shared_ptr<FileSys::VfsDirectory>;
+using VirtualFile = std::shared_ptr<FileSys::VfsFile>;
+
+// A class representing a file in an abstract filesystem.
+struct VfsFile : NonCopyable {
+    virtual ~VfsFile();
+
+    // Retrieves the file name.
+    virtual std::string GetName() const = 0;
+    // Retrieves the extension of the file name.
+    virtual std::string GetExtension() const;
+    // Retrieves the size of the file.
+    virtual size_t GetSize() const = 0;
+    // Resizes the file to new_size. Returns whether or not the operation was successful.
+    virtual bool Resize(size_t new_size) = 0;
+    // Gets a pointer to the directory containing this file, returning nullptr if there is none.
+    virtual std::shared_ptr<VfsDirectory> GetContainingDirectory() const = 0;
+
+    // Returns whether or not the file can be written to.
+    virtual bool IsWritable() const = 0;
+    // Returns whether or not the file can be read from.
+    virtual bool IsReadable() const = 0;
+
+    // The primary method of reading from the file. Reads length bytes into data starting at offset
+    // into file. Returns number of bytes successfully read.
+    virtual size_t Read(u8* data, size_t length, size_t offset = 0) const = 0;
+    // The primary method of writing to the file. Writes length bytes from data starting at offset
+    // into file. Returns number of bytes successfully written.
+    virtual size_t Write(const u8* data, size_t length, size_t offset = 0) = 0;
+
+    // Reads exactly one byte at the offset provided, returning boost::none on error.
+    virtual boost::optional<u8> ReadByte(size_t offset = 0) const;
+    // Reads size bytes starting at offset in file into a vector.
+    virtual std::vector<u8> ReadBytes(size_t size, size_t offset = 0) const;
+    // Reads all the bytes from the file into a vector. Equivalent to 'file->Read(file->GetSize(),
+    // 0)'
+    virtual std::vector<u8> ReadAllBytes() const;
+
+    // Reads an array of type T, size number_elements starting at offset.
+    // Returns the number of bytes (sizeof(T)*number_elements) read successfully.
+    template <typename T>
+    size_t ReadArray(T* data, size_t number_elements, size_t offset = 0) const {
+        static_assert(std::is_trivially_copyable<T>::value,
+                      "Data type must be trivially copyable.");
+
+        return Read(reinterpret_cast<u8*>(data), number_elements * sizeof(T), offset);
+    }
+
+    // Reads size bytes into the memory starting at data starting at offset into the file.
+    // Returns the number of bytes read successfully.
+    template <typename T>
+    size_t ReadBytes(T* data, size_t size, size_t offset = 0) const {
+        static_assert(std::is_trivially_copyable<T>::value,
+                      "Data type must be trivially copyable.");
+        return Read(reinterpret_cast<u8*>(data), size, offset);
+    }
+
+    // Reads one object of type T starting at offset in file.
+    // Returns the number of bytes read successfully (sizeof(T)).
+    template <typename T>
+    size_t ReadObject(T* data, size_t offset = 0) const {
+        static_assert(std::is_trivially_copyable<T>::value,
+                      "Data type must be trivially copyable.");
+        return Read(reinterpret_cast<u8*>(data), sizeof(T), offset);
+    }
+
+    // Writes exactly one byte to offset in file and retuns whether or not the byte was written
+    // successfully.
+    virtual bool WriteByte(u8 data, size_t offset = 0);
+    // Writes a vector of bytes to offset in file and returns the number of bytes successfully
+    // written.
+    virtual size_t WriteBytes(std::vector<u8> data, size_t offset = 0);
+
+    // Writes an array of type T, size number_elements to offset in file.
+    // Returns the number of bytes (sizeof(T)*number_elements) written successfully.
+    template <typename T>
+    size_t WriteArray(T* data, size_t number_elements, size_t offset = 0) {
+        static_assert(std::is_trivially_copyable<T>::value,
+                      "Data type must be trivially copyable.");
+
+        return Write(data, number_elements * sizeof(T), offset);
+    }
+
+    // Writes size bytes starting at memory location data to offset in file.
+    // Returns the number of bytes written successfully.
+    template <typename T>
+    size_t WriteBytes(T* data, size_t size, size_t offset = 0) {
+        static_assert(std::is_trivially_copyable<T>::value,
+                      "Data type must be trivially copyable.");
+        return Write(reinterpret_cast<u8*>(data), size, offset);
+    }
+
+    // Writes one object of type T to offset in file.
+    // Returns the number of bytes written successfully (sizeof(T)).
+    template <typename T>
+    size_t WriteObject(const T& data, size_t offset = 0) {
+        static_assert(std::is_trivially_copyable<T>::value,
+                      "Data type must be trivially copyable.");
+        return Write(&data, sizeof(T), offset);
+    }
+
+    // Renames the file to name. Returns whether or not the operation was successsful.
+    virtual bool Rename(const std::string& name) = 0;
+};
+
+// A class representing a directory in an abstract filesystem.
+struct VfsDirectory : NonCopyable {
+    virtual ~VfsDirectory();
+
+    // Retrives the file located at path as if the current directory was root. Returns nullptr if
+    // not found.
+    virtual std::shared_ptr<VfsFile> GetFileRelative(const std::string& path) const;
+    // Calls GetFileRelative(path) on the root of the current directory.
+    virtual std::shared_ptr<VfsFile> GetFileAbsolute(const std::string& path) const;
+
+    // Retrives the directory located at path as if the current directory was root. Returns nullptr
+    // if not found.
+    virtual std::shared_ptr<VfsDirectory> GetDirectoryRelative(const std::string& path) const;
+    // Calls GetDirectoryRelative(path) on the root of the current directory.
+    virtual std::shared_ptr<VfsDirectory> GetDirectoryAbsolute(const std::string& path) const;
+
+    // Returns a vector containing all of the files in this directory.
+    virtual std::vector<std::shared_ptr<VfsFile>> GetFiles() const = 0;
+    // Returns the file with filename matching name. Returns nullptr if directory dosen't have a
+    // file with name.
+    virtual std::shared_ptr<VfsFile> GetFile(const std::string& name) const;
+
+    // Returns a vector containing all of the subdirectories in this directory.
+    virtual std::vector<std::shared_ptr<VfsDirectory>> GetSubdirectories() const = 0;
+    // Returns the directory with name matching name. Returns nullptr if directory dosen't have a
+    // directory with name.
+    virtual std::shared_ptr<VfsDirectory> GetSubdirectory(const std::string& name) const;
+
+    // Returns whether or not the directory can be written to.
+    virtual bool IsWritable() const = 0;
+    // Returns whether of not the directory can be read from.
+    virtual bool IsReadable() const = 0;
+
+    // Returns whether or not the directory is the root of the current file tree.
+    virtual bool IsRoot() const;
+
+    // Returns the name of the directory.
+    virtual std::string GetName() const = 0;
+    // Returns the total size of all files and subdirectories in this directory.
+    virtual size_t GetSize() const;
+    // Returns the parent directory of this directory. Returns nullptr if this directory is root or
+    // has no parent.
+    virtual std::shared_ptr<VfsDirectory> GetParentDirectory() const = 0;
+
+    // Creates a new subdirectory with name name. Returns a pointer to the new directory or nullptr
+    // if the operation failed.
+    virtual std::shared_ptr<VfsDirectory> CreateSubdirectory(const std::string& name) = 0;
+    // Creates a new file with name name. Returns a pointer to the new file or nullptr if the
+    // operation failed.
+    virtual std::shared_ptr<VfsFile> CreateFile(const std::string& name) = 0;
+
+    // Creates a new file at the path relative to this directory. Also creates directories if
+    // they do not exist and is supported by this implementation. Returns nullptr on any failure.
+    virtual std::shared_ptr<VfsFile> CreateFileRelative(const std::string& path);
+
+    // Creates a new file at the path relative to root of this directory. Also creates directories
+    // if they do not exist and is supported by this implementation. Returns nullptr on any failure.
+    virtual std::shared_ptr<VfsFile> CreateFileAbsolute(const std::string& path);
+
+    // Creates a new directory at the path relative to this directory. Also creates directories if
+    // they do not exist and is supported by this implementation. Returns nullptr on any failure.
+    virtual std::shared_ptr<VfsDirectory> CreateDirectoryRelative(const std::string& path);
+
+    // Creates a new directory at the path relative to root of this directory. Also creates
+    // directories if they do not exist and is supported by this implementation. Returns nullptr on
+    // any failure.
+    virtual std::shared_ptr<VfsDirectory> CreateDirectoryAbsolute(const std::string& path);
+
+    // Deletes the subdirectory with name and returns true on success.
+    virtual bool DeleteSubdirectory(const std::string& name) = 0;
+    // Deletes all subdirectories and files of subdirectory with name recirsively and then deletes
+    // the subdirectory. Returns true on success.
+    virtual bool DeleteSubdirectoryRecursive(const std::string& name);
+    // Returnes whether or not the file with name name was deleted successfully.
+    virtual bool DeleteFile(const std::string& name) = 0;
+
+    // Returns whether or not this directory was renamed to name.
+    virtual bool Rename(const std::string& name) = 0;
+
+    // Returns whether or not the file with name src was successfully copied to a new file with name
+    // dest.
+    virtual bool Copy(const std::string& src, const std::string& dest);
+
+    // Interprets the file with name file instead as a directory of type directory.
+    // The directory must have a constructor that takes a single argument of type
+    // std::shared_ptr<VfsFile>. Allows to reinterpret container files (i.e NCA, zip, XCI, etc) as a
+    // subdirectory in one call.
+    template <typename Directory>
+    bool InterpretAsDirectory(const std::string& file) {
+        auto file_p = GetFile(file);
+        if (file_p == nullptr)
+            return false;
+        return ReplaceFileWithSubdirectory(file, std::make_shared<Directory>(file_p));
+    }
+
+protected:
+    // Backend for InterpretAsDirectory.
+    // Removes all references to file and adds a reference to dir in the directory's implementation.
+    virtual bool ReplaceFileWithSubdirectory(VirtualFile file, VirtualDir dir) = 0;
+};
+
+// A convenience partial-implementation of VfsDirectory that stubs out methods that should only work
+// if writable. This is to avoid redundant empty methods everywhere.
+struct ReadOnlyVfsDirectory : public VfsDirectory {
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    std::shared_ptr<VfsDirectory> CreateSubdirectory(const std::string& name) override;
+    std::shared_ptr<VfsFile> CreateFile(const std::string& name) override;
+    bool DeleteSubdirectory(const std::string& name) override;
+    bool DeleteFile(const std::string& name) override;
+    bool Rename(const std::string& name) override;
+};
+} // namespace FileSys