+/* 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>
+
+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;
+ }
+}
projects / notmuch / commitdiff