VFS: Add boilerplate

Common/File/VFS/DirectoryReader.cpp

@@ -29,3 +29,39 @@ bool DirectoryReader::GetFileInfo(const char *path, File::FileInfo *info) {
 	Path new_path = Path(path).StartsWith(path_) ? Path(path) : path_ / path;
 	return File::GetFileInfo(new_path, info);
 }
+
+class DirectoryReaderFileReference : public VFSFileReference {
+public:
+	Path path;
+};
+
+class DirectoryReaderOpenFile : public VFSOpenFile {
+public:
+	FILE *file;
+};
+
+VFSFileReference *DirectoryReader::GetFile(const char *path) {
+	return nullptr;
+}
+
+void DirectoryReader::ReleaseFile(VFSFileReference *reference) {
+	DirectoryReaderFileReference *file = (DirectoryReaderFileReference *)reference;
+}
+
+VFSOpenFile *DirectoryReader::OpenFileForRead(VFSFileReference *reference) {
+	DirectoryReaderFileReference *file = (DirectoryReaderFileReference *)reference;
+	return nullptr;
+}
+
+void DirectoryReader::Rewind(VFSOpenFile *openFile) {
+	DirectoryReaderOpenFile *file = (DirectoryReaderOpenFile *)openFile;
+}
+
+size_t DirectoryReader::Read(VFSOpenFile *openFile, uint8_t *buffer, size_t length) {
+	DirectoryReaderOpenFile *file = (DirectoryReaderOpenFile *)openFile;
+	return 0;
+}
+
+void DirectoryReader::CloseFile(VFSOpenFile *openFile) {
+	DirectoryReaderOpenFile *file = (DirectoryReaderOpenFile *)openFile;
+}

Common/File/VFS/DirectoryReader.h

@@ -9,6 +9,15 @@ class DirectoryReader : public VFSBackend {
 	explicit DirectoryReader(const Path &path);
 	// use delete[] on the returned value.
 	uint8_t *ReadFile(const char *path, size_t *size) override;
+
+	virtual VFSFileReference *GetFile(const char *path) override;
+	virtual void ReleaseFile(VFSFileReference *reference) override;
+
+	virtual VFSOpenFile *OpenFileForRead(VFSFileReference *reference) override;
+	virtual void Rewind(VFSOpenFile *openFile) override;
+	virtual size_t Read(VFSOpenFile *openFile, uint8_t *buffer, size_t length) override;
+	virtual void CloseFile(VFSOpenFile *openFile) override;
+
 	bool GetFileListing(const char *path, std::vector<File::FileInfo> *listing, const char *filter) override;
 	bool GetFileInfo(const char *path, File::FileInfo *info) override;
 	std::string toString() const override {
@@ -18,4 +27,3 @@ class DirectoryReader : public VFSBackend {
 private:
 	Path path_;
 };
-

Common/File/VFS/VFS.h

@@ -14,6 +14,22 @@
 // on the system level, like loading assets, and maybe texture packs. Also, as mentioned,
 // this one is read-only, so a bit smaller and simpler.
 
+// VFSBackend instances can be used on their own, without the VFS, to serve as an abstraction of
+// a single directory or ZIP file.
+
+// The VFSFileReference level of abstraction is there to hold things like zip file indices,
+// for fast re-open etc.
+
+class VFSFileReference {
+public:
+	virtual ~VFSFileReference() {}
+};
+
+class VFSOpenFile {
+public:
+	virtual ~VFSOpenFile() {}
+};
+
 // Common inteface parts between VFSBackend and VFS.
 // Sometimes you don't need the VFS multiplexing and only have a VFSBackend *, sometimes you do need it,
 // and it would be cool to be able to use the same interface, like when loading INI files.
@@ -27,6 +43,14 @@ class VFSBackend : public VFSInterface {
 public:
 	// use delete[] to release the returned memory.
 
+	virtual VFSFileReference *GetFile(const char *path) = 0;
+	virtual void ReleaseFile(VFSFileReference *file) = 0;
+
+	virtual VFSOpenFile *OpenFileForRead(VFSFileReference *reference) = 0;
+	virtual void Rewind(VFSOpenFile *file) = 0;
+	virtual size_t Read(VFSOpenFile *file, uint8_t *buffer, size_t length) = 0;
+	virtual void CloseFile(VFSOpenFile *file) = 0;
+
 	// Filter support is optional but nice to have
 	virtual bool GetFileListing(const char *path, std::vector<File::FileInfo> *listing, const char *filter = 0) = 0;
 	virtual bool GetFileInfo(const char *path, File::FileInfo *info) = 0;

Common/File/VFS/ZipFileReader.cpp

@@ -164,3 +164,37 @@ bool ZipFileReader::GetFileInfo(const char *path, File::FileInfo *info) {
 	info->size = zstat.size;
 	return true;
 }
+
+class ZipFileReaderFileReference : public VFSFileReference {
+public:
+};
+
+class ZipFileReaderOpenFile : public VFSOpenFile {
+public:
+};
+
+VFSFileReference *ZipFileReader::GetFile(const char *path) {
+	return nullptr;
+}
+
+void ZipFileReader::ReleaseFile(VFSFileReference *reference) {
+	ZipFileReaderFileReference *file = (ZipFileReaderFileReference *)reference;
+}
+
+VFSOpenFile *ZipFileReader::OpenFileForRead(VFSFileReference *reference) {
+	ZipFileReaderFileReference *file = (ZipFileReaderFileReference *)reference;
+	return nullptr;
+}
+
+void ZipFileReader::Rewind(VFSOpenFile *openFile) {
+	ZipFileReaderOpenFile *file = (ZipFileReaderOpenFile *)openFile;
+}
+
+size_t ZipFileReader::Read(VFSOpenFile *openFile, uint8_t *buffer, size_t length) {
+	ZipFileReaderOpenFile *file = (ZipFileReaderOpenFile *)openFile;
+	return 0;
+}
+
+void ZipFileReader::CloseFile(VFSOpenFile *openFile) {
+	ZipFileReaderOpenFile *file = (ZipFileReaderOpenFile *)openFile;
+}

Common/File/VFS/ZipFileReader.h

@@ -20,6 +20,15 @@ class ZipFileReader : public VFSBackend {
 	~ZipFileReader();
 	// use delete[] on the returned value.
 	uint8_t *ReadFile(const char *path, size_t *size) override;
+
+	VFSFileReference *GetFile(const char *path) override;
+	void ReleaseFile(VFSFileReference *reference) override;
+
+	VFSOpenFile *OpenFileForRead(VFSFileReference *reference) override;
+	void Rewind(VFSOpenFile *openFile) override;
+	size_t Read(VFSOpenFile *openFile, uint8_t *buffer, size_t length) override;
+	void CloseFile(VFSOpenFile *openFile) override;
+
 	bool GetFileListing(const char *path, std::vector<File::FileInfo> *listing, const char *filter) override;
 	bool GetFileInfo(const char *path, File::FileInfo *info) override;
 	std::string toString() const override {