[Dovecot] understand the struct message_header_line

[Alex Baule]

Timo...

Using the src/lib-mail/test-istream-header-filter.c as example, and
following your tips to jump my desired header value, but i need to store the
value from the Header filtered.

In the Exemple, the callback is this:

static void filter_callback(struct message_header_line *hdr,
                bool *matched, void *context ATTR_UNUSED)
{
    if (hdr != NULL && hdr->name_offset == 0) {
        /* drop first header */
        *matched = TRUE;
    }
}

What i try to understand is how the structs work, it's save the entire
header or every line from header call the callback function ?

hdr->name_offset is the size of elements in the struct ? (like a array of
message_header_line)


The void *context ATTR_UNUSED i can pass what i want to change ? like a
pointer to a variable ?