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/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */
/* Implemented against draft-ietf-imapext-sort-10 and
draft-ietf-imapext-thread-12 */
#include "lib.h"
#include "buffer.h"
#include "charset-utf8.h"
#include "message-header-decode.h"
#include "imap-base-subject.h"
static void pack_whitespace(buffer_t *buf)
{
char *data, *dest;
bool last_lwsp;
data = buffer_get_modifiable_data(buf, NULL);
/* check if we need to do anything */
while (*data != '\0') {
if (*data == '\t' || *data == '\n' || *data == '\r' ||
(*data == ' ' && (data[1] == ' ' || data[1] == '\t')))
break;
data++;
}
if (*data == '\0')
return;
/* @UNSAFE: convert/pack the whitespace */
dest = data; last_lwsp = FALSE;
while (*data != '\0') {
if (*data == '\t' || *data == ' ' ||
*data == '\r' || *data == '\n') {
if (!last_lwsp) {
*dest++ = ' ';
last_lwsp = TRUE;
}
} else {
*dest++ = *data;
last_lwsp = FALSE;
}
data++;
}
*dest = '\0';
data = buffer_get_modifiable_data(buf, NULL);
buffer_set_used_size(buf, (size_t) (dest - data)+1);
}
static void remove_subj_trailers(buffer_t *buf, size_t start_pos,
bool *is_reply_or_forward_r)
{
const char *data;
size_t orig_size, size;
/* subj-trailer = "(fwd)" / WSP */
data = buffer_get_data(buf, &orig_size);
if (orig_size < 1) /* size includes trailing \0 */
return;
for (size = orig_size-1; size > start_pos; ) {
if (data[size-1] == ' ')
size--;
else if (size >= 5 &&
memcmp(data + size - 5, "(FWD)", 5) == 0) {
*is_reply_or_forward_r = TRUE;
size -= 5;
} else {
break;
}
}
if (size != orig_size-1) {
buffer_set_used_size(buf, size);
buffer_append_c(buf, '\0');
}
}
static bool remove_blob(const char **datap)
{
const char *data = *datap;
if (*data != '[')
return FALSE;
data++;
while (*data != '\0' && *data != '[' && *data != ']')
data++;
if (*data != ']')
return FALSE;
data++;
if (*data == ' ')
data++;
*datap = data;
return TRUE;
}
static bool remove_subj_leader(buffer_t *buf, size_t *start_pos,
bool *is_reply_or_forward_r)
{
const char *data, *orig_data;
bool ret = FALSE;
/* subj-leader = (*subj-blob subj-refwd) / WSP
subj-blob = "[" *BLOBCHAR "]" *WSP
subj-refwd = ("re" / ("fw" ["d"])) *WSP [subj-blob] ":"
BLOBCHAR = %x01-5a / %x5c / %x5e-7f
; any CHAR except '[' and ']' */
orig_data = buf->data;
orig_data += *start_pos;
data = orig_data;
if (*data == ' ') {
/* independent from checks below - always removed */
data++; orig_data++;
*start_pos += 1;
ret = TRUE;
}
while (*data == '[') {
if (!remove_blob(&data))
return ret;
}
if (str_begins(data, "RE"))
data += 2;
else if (str_begins(data, "FWD"))
data += 3;
else if (str_begins(data, "FW"))
data += 2;
else
return ret;
if (*data == ' ')
data++;
if (*data == '[' && !remove_blob(&data))
return ret;
if (*data != ':')
return ret;
data++;
*start_pos += (size_t)(data - orig_data);
*is_reply_or_forward_r = TRUE;
return TRUE;
}
static bool remove_blob_when_nonempty(buffer_t *buf, size_t *start_pos)
{
const char *data, *orig_data;
orig_data = buf->data;
orig_data += *start_pos;
data = orig_data;
if (*data == '[' && remove_blob(&data) && *data != '\0') {
*start_pos += (size_t)(data - orig_data);
return TRUE;
}
return FALSE;
}
static bool remove_subj_fwd_hdr(buffer_t *buf, size_t *start_pos,
bool *is_reply_or_forward_r)
{
const char *data = buf->data;
size_t size = buf->used;
/* subj-fwd = subj-fwd-hdr subject subj-fwd-trl
subj-fwd-hdr = "[fwd:"
subj-fwd-trl = "]" */
if (!str_begins(data + *start_pos, "[FWD:"))
return FALSE;
if (data[size-2] != ']')
return FALSE;
*is_reply_or_forward_r = TRUE;
buffer_set_used_size(buf, size-2);
buffer_append_c(buf, '\0');
*start_pos += 5;
return TRUE;
}
const char *imap_get_base_subject_cased(pool_t pool, const char *subject,
bool *is_reply_or_forward_r)
{
buffer_t *buf;
size_t start_pos, subject_len;
bool found;
*is_reply_or_forward_r = FALSE;
subject_len = strlen(subject);
buf = buffer_create_dynamic(pool, subject_len);
/* (1) Convert any RFC 2047 encoded-words in the subject to
UTF-8. Convert all tabs and continuations to space.
Convert all multiple spaces to a single space. */
message_header_decode_utf8((const unsigned char *)subject, subject_len,
buf, uni_utf8_to_decomposed_titlecase);
buffer_append_c(buf, '\0');
pack_whitespace(buf);
start_pos = 0;
do {
/* (2) Remove all trailing text of the subject that matches
the subj-trailer ABNF, repeat until no more matches are
possible. */
remove_subj_trailers(buf, start_pos, is_reply_or_forward_r);
do {
/* (3) Remove all prefix text of the subject that
matches the subj-leader ABNF. */
found = remove_subj_leader(buf, &start_pos,
is_reply_or_forward_r);
/* (4) If there is prefix text of the subject that
matches the subj-blob ABNF, and removing that prefix
leaves a non-empty subj-base, then remove the prefix
text. */
found = remove_blob_when_nonempty(buf, &start_pos) ||
found;
/* (5) Repeat (3) and (4) until no matches remain. */
} while (found);
/* (6) If the resulting text begins with the subj-fwd-hdr ABNF
and ends with the subj-fwd-trl ABNF, remove the
subj-fwd-hdr and subj-fwd-trl and repeat from step (2). */
} while (remove_subj_fwd_hdr(buf, &start_pos, is_reply_or_forward_r));
/* (7) The resulting text is the "base subject" used in the
SORT. */
return (const char *)buf->data + start_pos;
}
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