xml_inline.c

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

#include "node.h"

typedef struct {
    uint8_t *file_str;
    size_t file_len;
    size_t offset;
} xml_inline_ocb_t;  // open context block

/**
 * This call is generated by the c-atom's tool xml2c_inliner.py
 * simply run 'make prebuild'
 * @param path
 * @param size
 * @return
 */
const char *xml_inline_find_file(const char *path, size_t *size);

static int xml_inline_open_callback(FILE *file, const char *path) {
    size_t filesize;

    if (file->private_data == NULL) {
        file->private_data = calloc(1, sizeof(xml_inline_ocb_t));
    }

    xml_inline_ocb_t *ocb = (xml_inline_ocb_t *)file->private_data;

    const char *file_string = xml_inline_find_file(path, &filesize);

    if (file_string == NULL) {
        errno = ENOENT;
        return -1;
    }
    // check size
#define MAXLEN (filesize + 100)
    ocb->file_len = strnlen(file_string, MAXLEN);
    if (ocb->file_len >= MAXLEN) {
        errno = EFBIG;
        return -1;
    }
    if (ocb->file_len != filesize) {
        errno = EIO;
        return -1;
    }

    ocb->file_str = (uint8_t *)file_string;

    ocb->offset = 0;

    return 0;
}

static ssize_t xml_inline_read_callback(FILE *file, char *buf, size_t count) {
    xml_inline_ocb_t *ocb = (xml_inline_ocb_t *)file->private_data;

    size_t bytes_left = ocb->file_len - ocb->offset;
    ssize_t br = count > bytes_left ? bytes_left : count;

    if (br > 0) {
        memcpy(buf, ocb->file_str + ocb->offset, br);
        ocb->offset += br;
    }

    errno = 0;

    return br;
}

static int xml_inline_close_callback(FILE *file) {
    xml_inline_ocb_t *ocb = (xml_inline_ocb_t *)file->private_data;
    // TODO
    return 0;
}

int xml_inline_mount(const char *mount_to) {
    struct file_operations f_op = {.open = xml_inline_open_callback,
                                   .write = NULL,
                                   .read = xml_inline_read_callback,
                                   .close = xml_inline_close_callback,
                                   .dev = NULL};
    struct node *node = node_mount(mount_to, &f_op);
    return 0;
}