Directory.hpp

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// ======================================================================
// \title Os/Directory.hpp
// \brief Os::Directory interface definition
// ======================================================================

#ifndef _OS_DIRECTORY_HPP_
#define _OS_DIRECTORY_HPP_

#include <Fw/FPrimeBasicTypes.hpp>
#include <Fw/Types/String.hpp>
#include <Os/Os.hpp>

namespace Os {

struct DirectoryHandle {};

class DirectoryInterface {
  public:
    enum Status {
        OP_OK,           
        DOESNT_EXIST,    
        NO_PERMISSION,   
        NOT_OPENED,      
        NOT_DIR,         
        NO_MORE_FILES,   
        FILE_LIMIT,      
        BAD_DESCRIPTOR,  
        ALREADY_EXISTS,  
        NOT_SUPPORTED,   
        OTHER_ERROR,     
    };

    enum OpenMode {
        READ,               
        CREATE_IF_MISSING,  
        CREATE_EXCLUSIVE,   
        MAX_OPEN_MODE       
    };

    DirectoryInterface() = default;

    virtual ~DirectoryInterface() = default;

    DirectoryInterface(const DirectoryInterface& other) = delete;

    DirectoryInterface& operator=(const DirectoryInterface& other) = delete;

    virtual DirectoryHandle* getHandle() = 0;

    static DirectoryInterface* getDelegate(DirectoryHandleStorage& aligned_new_memory);

    // -----------------------------------------------------------------
    // Directory operations to be implemented by an OSAL implementation
    // -----------------------------------------------------------------
    // These functions are to be overridden in each OS implementation
    // See an example in in Os/Posix/Directory.hpp

    virtual Status open(const char* path, OpenMode mode) = 0;

    virtual Status rewind() = 0;

    virtual Status read(char* fileNameBuffer, FwSizeType buffSize) = 0;

    // virtual Status read(Fw::StringBase& filename) = 0;

    virtual void close() = 0;
};

class Directory final : public DirectoryInterface {
  public:
    Directory();

    ~Directory() final;

    DirectoryHandle* getHandle() override;

    // ------------------------------------------------------------
    // Implementation-specific Directory member functions
    // ------------------------------------------------------------
    // These functions are overridden in each OS implementation (e.g. in Os/Posix/Directory.hpp)

    Status open(const char* path, OpenMode mode) override;

    bool isOpen();

    Status rewind() override;

    Status read(char* fileNameBuffer, FwSizeType buffSize) override;

    void close() override;

    // ------------------------------------------------------------
    // Common functions built on top of OS-specific functions
    // ------------------------------------------------------------

    Status read(Fw::StringBase& filename);

    Status readDirectory(Fw::String filenameArray[], const FwSizeType arraySize, FwSizeType& filenameCount);

    Status getFileCount(FwSizeType& fileCount);

  private:
    bool m_is_open;  

  private:
    // This section is used to store the implementation-defined Directory handle. To Os::Directory and fprime, this type
    // is opaque and thus normal allocation cannot be done. Instead, we allow the implementor to store then handle in
    // the byte-array here and set `handle` to that address for storage.
    alignas(FW_HANDLE_ALIGNMENT) DirectoryHandleStorage m_handle_storage;  
    DirectoryInterface& m_delegate;
};

}  // namespace Os

#endif