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#ifndef CONSOLE_H

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#define CONSOLE_H

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/**

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 * @file

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 *

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 * An interactive line-based console interface for runtime configuration.

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 *

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 * This uses the GNU readline library to implement the console, and hence, the console uses global state, and there

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 * can only be one console per process - not that it should matter, since the console requires a tty.

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 *

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 * XXX: the log module interferes with this

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 */

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#include "error.h"

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#include <event2/event.h>

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#include <stdbool.h>

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/**

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 * The console state.

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 */

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struct console;

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/**

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 * Return codes for console_callbacks::on_line

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 */

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enum console_line_status {

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    /** 

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     * OK, line was processed, display prompt for next input line 

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     */

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    CONSOLE_CONTINUE,

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    /**

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     * Line is still executing, do not prompt for next line .

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     *

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     * Call console_continue() once the line was handled.

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     */

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    CONSOLE_WAIT,

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};

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/**

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 * Callbacks for event-based actions

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 */

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struct console_callbacks {

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    /**

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     * A line was read from the console.

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     *

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     * The return code defines how execution continues.

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     */

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    enum console_line_status (*on_line) (const char *line, void *arg);

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    /**

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     * EOF was read on the console.

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     *

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     * Note that for interactive consoles, EOF isn't actually EOF - there might be multiple EOFs...

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     */

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    void (*on_eof) (void *arg);

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};

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/**

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 * Configuration info for console operation

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 */

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struct console_config {

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    /** The prompt to use when displaying lines */

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    const char *prompt;

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};

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/**

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 * Initialize the console, setting up the TTY and input handler.

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 *

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 * @param console_ptr returned new console struct

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 * @param ev_base the libevent base to use

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 * @param config configuration things for the console

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 * @param callbacks optional callbacks, can be updated later

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 * @param cb_arg option callback argument, can be updated later

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 * @param err returned error info

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 */

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err_t console_init (struct console **console_ptr, struct event_base *ev_base, const struct console_config *config,

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        const struct console_callbacks *callbacks, void *cb_arg, struct error_info *err);

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/**

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 * Replace the current callbacks with the given new ones.

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 */

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void console_set_callbacks (struct console *console, const struct console_callbacks *callbacks, void *cb_arg);

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/**

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 * Continue reading input after a CONSOLE_WAIT return code from console_callbacks::on_line.

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 *

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 * This does nothing if the console is not currently in the waiting state (i.e. last console_callbacks::on_line

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 * returned CONSOLE_WAIT).

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 */

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void console_continue (struct console *console);

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/**

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 * Output a full line (without included newline) on the console, trying not to interfere with the input too much.

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 */

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err_t console_print (struct console *console, const char *line);

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/**

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 * Install this console as the log output handler

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 */

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void console_set_log_output (struct console *console);

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/**

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 * Deinitialize the console, restoring the TTY and releasing resources

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 */

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void console_destroy (struct console *console);

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#endif /* CONSOLE_H */