/* message.c - Utility functions for parsing an email message for notmuch.
*
* Copyright © 2009 Carl Worth
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see http://www.gnu.org/licenses/ .
*
* Author: Carl Worth <cworth@cworth.org>
*/
#include <stdarg.h>
#include "notmuch-private.h"
#include <glib.h> /* GHashTable */
struct _notmuch_message {
/* File objects */
int fd;
void *map;
/* Header storage */
int restrict_headers;
GHashTable *headers;
/* Parsing state */
char *start;
size_t size;
const char *next_line;
int parsing_started;
int parsing_finished;
};
static int
strcase_equal (const void *a, const void *b)
{
return strcasecmp (a, b) == 0;
}
static unsigned int
strcase_hash (const void *ptr)
{
const char *s = ptr;
/* This is the djb2 hash. */
unsigned int hash = 5381;
while (s && *s) {
hash = ((hash << 5) + hash) + tolower (*s);
s++;
}
return hash;
}
notmuch_message_t *
notmuch_message_open (const char *filename)
{
notmuch_message_t *message;
struct stat st;
message = xcalloc (1, sizeof (notmuch_message_t));
message->fd = open (filename, O_RDONLY);
if (message->fd < 0)
goto FAIL;
if (fstat (message->fd, &st) < 0)
goto FAIL;
message->map = mmap (NULL, st.st_size, PROT_READ, MAP_PRIVATE,
message->fd, 0);
if (message->map == MAP_FAILED)
goto FAIL;
message->headers = g_hash_table_new_full (strcase_hash,
strcase_equal,
free,
free);
message->start = (char *) message->map;
message->size = st.st_size;
message->next_line = message->start;
message->parsing_started = 0;
message->parsing_finished = 0;
return message;
FAIL:
fprintf (stderr, "Error opening %s: %s\n", filename, strerror (errno));
notmuch_message_close (message);
return NULL;
}
void
notmuch_message_close (notmuch_message_t *message)
{
if (message == NULL)
return;
if (message->headers)
g_hash_table_unref (message->headers);
if (message->map)
munmap (message->map, message->size);
if (message->fd)
close (message->fd);
free (message);
}
void
notmuch_message_restrict_headersv (notmuch_message_t *message,
va_list va_headers)
{
char *header;
if (message->parsing_started ) {
fprintf (stderr, "Error: notmuch_message_restrict_headers called after parsing has started\n");
exit (1);
}
while (1) {
header = va_arg (va_headers, char*);
if (header == NULL)
break;
g_hash_table_insert (message->headers,
xstrdup (header), NULL);
}
message->restrict_headers = 1;
}
void
notmuch_message_restrict_headers (notmuch_message_t *message, ...)
{
va_list va_headers;
va_start (va_headers, message);
notmuch_message_restrict_headersv (message, va_headers);
}
/* With our mmapped file, we don't get the benefit of terminated
* strings, so we can't use things like strchr(). We don't even know
* if there's a newline at the end of the file so we also have to be
* careful of that. Basically, every time we advance a pointer while
* parsing we must ensure we don't go beyond our buffer.
*/
#define WITHIN(s) (((s) - message->start) < (message->size -1))
/* In each of the macros below, "without overrunning the buffer" means
* that the macro will never dereference a character beyond the end of
* the buffer. However, all of the macros may return a pointer
* pointing to the first character beyond the buffer. So callers
* should test with WITHIN before dereferencing the result. */
/* Advance 'ptr' until pointing at a non-space character in the same
* line, (without overrunning the buffer) */
#define SKIP_SPACE_IN_LINE(ptr) \
while (WITHIN (ptr) && (*(ptr) == ' ' || *(ptr) == '\t')) \
(ptr)++;
/* Advance 'ptr' until pointing at a non-space character, (without
* overrunning the buffer) */
#define SKIP_SPACE(ptr) \
while (WITHIN (ptr) && isspace(*(ptr))) \
(ptr)++;
/* Advance 'ptr' to the first occurrence of 'c' within the same
* line, (without overrunning the buffer). */
#define ADVANCE_TO(ptr, c) \
while (WITHIN (ptr) && *(ptr) != '\n' && \
*(ptr) != (c)) \
{ \
(ptr)++; \
}
/* Advance 'ptr' to the beginning of the next line not starting with
* an initial tab character, (without overruning the buffer). */
#define ADVANCE_TO_NEXT_HEADER_LINE(ptr) \
do { \
ADVANCE_TO ((ptr), '\n'); \
if (WITHIN (ptr)) \
(ptr)++; \
} while (WITHIN (ptr) && \
(*(ptr) == '\t' || *(ptr) == ' '));
char *
copy_header_value (const char *start, const char *end)
{
const char *s;
char *result, *r;
int was_newline = 0;
result = xmalloc (end - start + 1);
s = start;
r = result;
while (s < end) {
if (*s == '\n') {
was_newline = 1;
} else {
if (*s == '\t' && was_newline)
*r = ' ';
else
*r = *s;
r++;
was_newline = 0;
}
s++;
}
*r = '\0';
return result;
}
const char *
notmuch_message_get_header (notmuch_message_t *message,
const char *header_desired)
{
int contains;
const char *s, *colon;
char *header, *value;
int match;
message->parsing_started = 1;
contains = g_hash_table_lookup_extended (message->headers,
header_desired, NULL,
(gpointer *) &value);
if (contains)
return value;
if (message->parsing_finished)
return NULL;
while (1) {
s = message->next_line;
if (*s == '\n') {
message->parsing_finished = 1;
return NULL;
}
if (*s == '\t') {
fprintf (stderr, "Warning: Unexpected continued value\n");
ADVANCE_TO_NEXT_HEADER_LINE (message->next_line);
continue;
}
colon = s;
ADVANCE_TO (colon, ':');
if (! WITHIN (colon) || *colon == '\n') {
fprintf (stderr, "Warning: Unexpected non-header line: %s\n", s);
ADVANCE_TO_NEXT_HEADER_LINE (message->next_line);
continue;
}
header = xstrndup (s, colon - s);
if (message->restrict_headers &&
! g_hash_table_lookup_extended (message->headers,
header, NULL, NULL))
{
free (header);
message->next_line = colon;
ADVANCE_TO_NEXT_HEADER_LINE (message->next_line);
continue;
}
s = colon + 1;
SKIP_SPACE_IN_LINE (s);
message->next_line = s;
ADVANCE_TO_NEXT_HEADER_LINE (message->next_line);
value = copy_header_value (s, message->next_line);
match = (strcasecmp (header, header_desired) == 0);
g_hash_table_insert (message->headers, header, value);
if (match)
return value;
}
}
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