42sh/src/io_backend/io_backend.h

#ifndef IO_BACKEND_H
#define IO_BACKEND_H

#include <sys/types.h>

// Error codes
#define IOB_ERROR_GENERIC -1
#define IOB_ERROR_BAD_ARG -2
#define IOB_ERROR_MODULE_NOT_INITIALIZED -3
#define IOB_ERROR_MODULE_ALREADY_INITALIZED -4
#define IOB_ERROR_CANNOT_OPEN_FILE -5

enum iob_mode {
    IOB_MODE_NULL = 0,
    IOB_MODE_STDIN,
    IOB_MODE_SCRIPT,
    IOB_MODE_CMD
};

enum iob_state {
    IOB_STATE_NOT_INITIALIZED,
    IOB_STATE_READY,
    IOB_STATE_FINISHED,
    IOB_STATE_ERROR
};

/* @struct iob_context
 * @var mode
 * @var args contains
 *        the script name when mode is set to IOB_MODE_SCRIPT,
 *        the command to execute when mode is set to IOB_MODE_CMD
 */
struct iob_context {
    enum iob_mode mode;
    char* args;
};

/*
 * @brief Initializes the IO Backend module
 * 
 * @param context contains the input mode and the args
 * @return 0 on success, the corresponding error code otherwise
 */
int iob_init(struct iob_context *context);

/* @brief Closes the opened buffers and the module gracefully
 */
void iob_close(void);

/* @brief reads at most one line of the input and stores it into *stream
 *
 * @param stream is a pointer that will be set to a string to parse
 * @return the number of read characters if positive,
 *         zero if finished (reached EOF),
 *         the error code otherwise
 */
ssize_t stream_read(char** stream);

#endif /* ! IO_BACKEND_H */