app_ui.c

《Beginning Linux Programming》书的配置实例源代码。

#define _XOPEN_SOURCE

#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>

#include "cd_data.h"

#define TMP_STRING_LEN 125 /* this number must be larger than the biggest
                              single string in any database structure */

/* Menu options */
typedef enum {
    mo_invalid,
    mo_add_cat,
    mo_add_tracks,
    mo_del_cat,
    mo_find_cat,
    mo_list_cat_tracks,
    mo_del_tracks,
    mo_count_entries,
    mo_exit
} menu_options;

/* local prototypes */
static int command_mode(int argc, char *argv[]);
static void announce(void);
static menu_options show_menu(const cdc_entry *current_cdc);
static int get_confirm(const char *question);
static int enter_new_cat_entry(cdc_entry *entry_to_update);
static void enter_new_track_entries(const cdc_entry *entry_to_add_to);
static void del_cat_entry(const cdc_entry *entry_to_delete);
static void del_track_entries(const cdc_entry *entry_to_delete);
static cdc_entry find_cat(void);
static void list_tracks(const cdc_entry *entry_to_use);
static void count_all_entries(void);
static void display_cdc(const cdc_entry *cdc_to_show);
static void display_cdt(const cdt_entry *cdt_to_show);
static void strip_return(char *string_to_strip);

void main(int argc, char *argv[]) {
    menu_options current_option;
    cdc_entry current_cdc_entry;
    int command_result;

    memset(&current_cdc_entry, '\0', sizeof(current_cdc_entry));

    if (argc > 1) {
        command_result = command_mode(argc, argv);
        exit(command_result);
    }
       
    announce();

    if (!database_initialize(0)) {
        fprintf(stderr, "Sorry, unable to initialize database\n");
        fprintf(stderr, "To create a new database use %s -i\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    while(current_option != mo_exit) {
        current_option = show_menu(&current_cdc_entry);

        switch(current_option) {
            case mo_add_cat:
                if (enter_new_cat_entry(&current_cdc_entry)) {
                    if (!add_cdc_entry(current_cdc_entry)) {
                        fprintf(stderr, "Failed to add new entry\n");
                        memset(&current_cdc_entry, '\0', sizeof(current_cdc_entry));
                    }
                }
                break;
            case mo_add_tracks:
                enter_new_track_entries(&current_cdc_entry);
                break;
            case mo_del_cat:
                del_cat_entry(&current_cdc_entry);
                break;
                break;
            case mo_find_cat:
                current_cdc_entry = find_cat();
                break;
            case mo_list_cat_tracks:
                list_tracks(&current_cdc_entry);
                break;
            case mo_del_tracks:
                del_track_entries(&current_cdc_entry);
                break;
            case mo_count_entries:
                count_all_entries();
                break;
            case mo_exit:
                break;
            case mo_invalid:
                break;
            default:
                break;
        } /* switch */
    } /* while */

    database_close();
   
    exit(EXIT_SUCCESS);
} /* main */

static void announce(void) {
    printf("\n\nWelcome to the demonstration CD catalog database program\n");
} /* announce */

static menu_options show_menu(const cdc_entry *cdc_selected) {
    char tmp_str[TMP_STRING_LEN + 1];
    menu_options option_chosen = mo_invalid;

    while (option_chosen == mo_invalid) {
        if (cdc_selected->catalog[0])  {      
            printf("\n\nCurrent entry: ");
            printf("%s, %s, %s, %s\n", cdc_selected->catalog,
                   cdc_selected->title,
                   cdc_selected->type,
                   cdc_selected->artist);

            printf("\n");
            printf("1 - add new CD\n");
            printf("2 - search for a CD\n");
            printf("3 - count the CDs and tracks in the database\n");        
            printf("4 - re-enter tracks for current CD\n");
            printf("5 - delete this CD, and all it's tracks\n");
            printf("6 - list tracks for this CD\n");
            printf("q - quit\n");
            printf("\nOption: ");
            fgets(tmp_str, TMP_STRING_LEN, stdin);
            switch(tmp_str[0]) {
                case '1': option_chosen = mo_add_cat; break;
                case '2': option_chosen = mo_find_cat; break;
                case '3': option_chosen = mo_count_entries; break;
                case '4': option_chosen = mo_add_tracks; break;
                case '5': option_chosen = mo_del_cat; break;
                case '6': option_chosen = mo_list_cat_tracks; break;
                case 'q': option_chosen = mo_exit; break;
            }
        }
        else {
            printf("\n\n");            
            printf("1 - add new CD\n");
            printf("2 - search for a CD\n");
            printf("3 - count the CDs and tracks in the database\n");
            printf("q - quit\n");
            printf("\nOption: ");            
            fgets(tmp_str, TMP_STRING_LEN, stdin);
            switch(tmp_str[0]) {
                case '1': option_chosen = mo_add_cat; break;
                case '2': option_chosen = mo_find_cat; break;
                case '3': option_chosen = mo_count_entries; break;
                case 'q': option_chosen = mo_exit; break;
            }
        }            
    } /* while */
    return(option_chosen);
} /* show_menu */

static int get_confirm(const char *question) {
    char tmp_str[TMP_STRING_LEN + 1];
    
    printf("%s", question);
    fgets(tmp_str, TMP_STRING_LEN, stdin);
    if (tmp_str[0] == 'Y' || tmp_str[0] == 'y') {
        return(1);
    }
    return(0);
} /* get_confirm */

                
static int enter_new_cat_entry(cdc_entry *entry_to_update) {
    cdc_entry new_entry;
    char tmp_str[TMP_STRING_LEN + 1];

    memset(&new_entry, '\0', sizeof(new_entry));

    printf("Enter catalog entry: ");
    (void)fgets(tmp_str, TMP_STRING_LEN, stdin);
    strip_return(tmp_str);
    strncpy(new_entry.catalog, tmp_str, CAT_CAT_LEN - 1);

    printf("Enter title: ");
    (void)fgets(tmp_str, TMP_STRING_LEN, stdin);
    strip_return(tmp_str);    
    strncpy(new_entry.title, tmp_str, CAT_TITLE_LEN - 1);

    printf("Enter type: ");
    (void)fgets(tmp_str, TMP_STRING_LEN, stdin);
    strip_return(tmp_str);    
    strncpy(new_entry.type, tmp_str, CAT_TYPE_LEN - 1);

    printf("Enter artist: ");
    (void)fgets(tmp_str, TMP_STRING_LEN, stdin);
    strip_return(tmp_str);    
    strncpy(new_entry.artist, tmp_str, CAT_ARTIST_LEN - 1);

    printf("\nNew catalog entry entry is :-\n");
    display_cdc(&new_entry);
    if (get_confirm("Add this entry ?")) {
            memcpy(entry_to_update, &new_entry, sizeof(new_entry));
            return(1);
    }
    return(0);
} /* add_new_cdc_entry */
        
static void enter_new_track_entries(const cdc_entry *entry_to_add_to) {
    cdt_entry new_track, existing_track;
    char tmp_str[TMP_STRING_LEN + 1];    
    int track_no = 1;

    if (entry_to_add_to->catalog[0] == '\0') return;
    printf("\nUpdating tracks for %s\n", entry_to_add_to->catalog);
    printf("Press return to leave existing description unchanged,\n");
    printf(" a single d to delete this and remaining tracks,\n");
    printf(" or new track description\n");
    
    while(1) {
        memset(&new_track, '\0', sizeof(new_track));
        existing_track = get_cdt_entry(entry_to_add_to->catalog, track_no);
        if (existing_track.catalog[0]) {
            printf("\tTrack %d: %s\n", track_no, existing_track.track_txt);
            printf("\tNew text: ");
        }
        else {
            printf("\tTrack %d description: ", track_no);
        }
        fgets(tmp_str, TMP_STRING_LEN, stdin);
        strip_return(tmp_str);
        if (strlen(tmp_str) == 0) {
            if (existing_track.catalog[0] == '\0') {
                    /* no existing entry, so finished adding */
                break;
            }
            else {
                /* leaves existing entry, jump to next track */
                track_no++;
                continue;
            }
        }
        if ((strlen(tmp_str) == 1) && tmp_str[0] == 'd') {
                /* delete this and remaining tracks */
            while (del_cdt_entry(entry_to_add_to->catalog, track_no)) {
                track_no++;
            }
            break;
        }
        
            /* if we get here then adding or updating track */
        strncpy(new_track.track_txt, tmp_str, TRACK_TTEXT_LEN - 1);
        strcpy(new_track.catalog, entry_to_add_to->catalog);
        new_track.track_no = track_no;
        if (!add_cdt_entry(new_track)) {
            fprintf(stderr, "Failed to add new track\n");
            break;
        }
        track_no++;
    } /* while */
} /* enter_new_track_entries */

static void del_cat_entry(const cdc_entry *entry_to_delete) {
    int track_no = 1;
    int delete_ok;
    
    display_cdc(entry_to_delete);
    if (get_confirm("Delete this entry and all it's tracks? ")) {
        do {
            delete_ok = del_cdt_entry(entry_to_delete->catalog, track_no);
            track_no++;
        } while(delete_ok);
        
        if (!del_cdc_entry(entry_to_delete->catalog)) {
            fprintf(stderr, "Failed to delete entry\n");
        }
    }
} /* del_cat_entry */

static void del_track_entries(const cdc_entry *entry_to_delete) {
    int track_no = 1;
    int delete_ok;
    
    display_cdc(entry_to_delete);
    if (get_confirm("Delete tracks for this entry? ")) {
        do {
            delete_ok = del_cdt_entry(entry_to_delete->catalog, track_no);
            track_no++;
        } while(delete_ok);
    }
} /* del_track_entries */

static cdc_entry find_cat(void) {
    cdc_entry item_found;
    char tmp_str[TMP_STRING_LEN + 1];    
    int first_call = 1;
    int any_entry_found = 0;
    int string_ok;
    int entry_selected = 0;

    do {
        string_ok = 1;
        printf("Enter string to search for in catalog entry: ");
        fgets(tmp_str, TMP_STRING_LEN, stdin);
        strip_return(tmp_str);
        if (strlen(tmp_str) > CAT_CAT_LEN) {
            fprintf(stderr, "Sorry, string too long, maximum \
                    %d characters\n", CAT_CAT_LEN);
            string_ok = 0;
        }
    } while (!string_ok);

    while (!entry_selected) {
        item_found = search_cdc_entry(tmp_str, &first_call);
        if (item_found.catalog[0] != '\0') {
            any_entry_found = 1;
            printf("\n");
            display_cdc(&item_found);
            if (get_confirm("This entry? ")) {
                entry_selected = 1;
            }
        } else {
            if (any_entry_found) printf("Sorry, no more matches found\n");
            else printf("Sorry, nothing found\n");
            break;
        }
    }
    return(item_found);
} /* find_cat */

static void list_tracks(const cdc_entry *entry_to_use) {
    int track_no = 1;
    cdt_entry entry_found;

    display_cdc(entry_to_use);
    printf("\nTracks\n");
    do {
            entry_found = get_cdt_entry(entry_to_use->catalog, track_no);
            if (entry_found.catalog[0]) {
                display_cdt(&entry_found);
                track_no++;
            }
    } while(entry_found.catalog[0]);
    (void)get_confirm("Press return");
} /* list_tracks */

static void count_all_entries(void) {
    int cd_entries_found = 0;
    int track_entries_found = 0;
    cdc_entry cdc_found;
    cdt_entry cdt_found;
    int track_no = 1;
    int first_time = 1;
    char *search_string = "";

    do {
        cdc_found = search_cdc_entry(search_string, &first_time);
        if (cdc_found.catalog[0]) {
            cd_entries_found++;
            track_no = 1;
            do {
                cdt_found = get_cdt_entry(cdc_found.catalog, track_no);
                if (cdt_found.catalog[0]) {
                    track_entries_found++;
                    track_no++;
                }
            } while (cdt_found.catalog[0]);
        }
    } while (cdc_found.catalog[0]);

    printf("Found %d CDs, with a total of %d tracks\n", 
           cd_entries_found, track_entries_found);
    (void)get_confirm("Press return");
    
} /* count_all_entries */ 
    

static void display_cdc(const cdc_entry *cdc_to_show) {
    printf("Catalogue: %s\n", cdc_to_show->catalog);
    printf("\ttitle: %s\n", cdc_to_show->title);
    printf("\ttype: %s\n", cdc_to_show->type);
    printf("\tartist: %s\n", cdc_to_show->artist);
} /* display_cdc */

static void display_cdt(const cdt_entry *cdt_to_show) {
    printf("%d: %s\n", cdt_to_show->track_no, cdt_to_show->track_txt);
} /* display_cdt */

static void strip_return(char *string_to_strip) {
    int len;

    len = strlen(string_to_strip);
    if (string_to_strip[len - 1] == '\n') string_to_strip[len - 1] = '\0';
} /* strip_return */


static int command_mode(int argc, char *argv[]) {
    int c;
    int result = EXIT_SUCCESS;
    char *prog_name = argv[0];

        /* these externals used by getopt************************
    extern char *optarg;
    extern optind, opterr, optopt; ***************************/

        /*************  Neil - getopt() in unistd only if __USE_POSIX2
          any idea what this means or why? **************************/
    while ((c = getopt(argc, argv, ":i")) != -1) {
        switch(c) {
            case 'i':
                if (!database_initialize(1)) {
                    result = EXIT_FAILURE;
                    fprintf(stderr, "Failed to initialize database\n");
                }
                break;
            case ':':
            case '?':
            default:
                fprintf(stderr, "Usage: %s [-i]\n", prog_name);
                result = EXIT_FAILURE;
                break;
        } /* switch */
    } /* while */
    return(result);
} /* command_mode */