X-Git-Url: https://git.notmuchmail.org/git?p=notmuch;a=blobdiff_plain;f=lib%2Fmessage.cc;h=cb313326270e6bc3b0ba5813a5491269e5a62ebb;hp=adcd07d6687e0e49cf716a311dab2f2205bcfc24;hb=a8a270522231b186493ecd97d56a1343382d51d8;hpb=b3caef1f0659dac8183441357c8fee500a940889

diff --git a/lib/message.cc b/lib/message.cc
index adcd07d6..cb313326 100644
--- a/lib/message.cc
+++ b/lib/message.cc
@@ -13,32 +13,47 @@
  * 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/ .
+ * along with this program.  If not, see https://www.gnu.org/licenses/ .
  *
  * Author: Carl Worth <cworth@cworth.org>
  */
 
 #include "notmuch-private.h"
 #include "database-private.h"
+#include "message-private.h"
 
 #include <stdint.h>
 
 #include <gmime/gmime.h>
 
-struct _notmuch_message {
+struct visible _notmuch_message {
     notmuch_database_t *notmuch;
     Xapian::docid doc_id;
     int frozen;
     char *message_id;
     char *thread_id;
     char *in_reply_to;
-    notmuch_filename_list_t *filename_list;
+    notmuch_string_list_t *tag_list;
+    notmuch_string_list_t *filename_term_list;
+    notmuch_string_list_t *filename_list;
     char *author;
     notmuch_message_file_t *message_file;
+    notmuch_string_list_t *property_term_list;
+    notmuch_string_map_t *property_map;
     notmuch_message_list_t *replies;
     unsigned long flags;
+    /* For flags that are initialized on-demand, lazy_flags indicates
+     * if each flag has been initialized. */
+    unsigned long lazy_flags;
+
+    /* Message document modified since last sync */
+    notmuch_bool_t modified;
+
+    /* last view of database the struct is synced with */
+    unsigned long last_view;
 
     Xapian::Document doc;
+    Xapian::termcount termpos;
 };
 
 #define ARRAY_SIZE(arr) (sizeof (arr) / sizeof (arr[0]))
@@ -46,16 +61,16 @@ struct _notmuch_message {
 struct maildir_flag_tag {
     char flag;
     const char *tag;
-    bool inverse;
+    notmuch_bool_t inverse;
 };
 
 /* ASCII ordered table of Maildir flags and associated tags */
 static struct maildir_flag_tag flag2tag[] = {
-    { 'D', "draft",   false},
-    { 'F', "flagged", false},
-    { 'P', "passed",  false},
-    { 'R', "replied", false},
-    { 'S', "unread",  true }
+    { 'D', "draft",   FALSE},
+    { 'F', "flagged", FALSE},
+    { 'P', "passed",  FALSE},
+    { 'R', "replied", FALSE},
+    { 'S', "unread",  TRUE }
 };
 
 /* We end up having to call the destructor explicitly because we had
@@ -96,14 +111,22 @@ _notmuch_message_create_for_document (const void *talloc_owner,
 
     message->frozen = 0;
     message->flags = 0;
+    message->lazy_flags = 0;
+
+    /* the message is initially not synchronized with Xapian */
+    message->last_view = 0;
 
     /* Each of these will be lazily created as needed. */
     message->message_id = NULL;
     message->thread_id = NULL;
     message->in_reply_to = NULL;
+    message->tag_list = NULL;
+    message->filename_term_list = NULL;
     message->filename_list = NULL;
     message->message_file = NULL;
     message->author = NULL;
+    message->property_term_list = NULL;
+    message->property_map = NULL;
 
     message->replies = _notmuch_message_list_create (message);
     if (unlikely (message->replies == NULL)) {
@@ -123,6 +146,7 @@ _notmuch_message_create_for_document (const void *talloc_owner,
     talloc_set_destructor (message, _notmuch_message_destructor);
 
     message->doc = doc;
+    message->termpos = 0;
 
     return message;
 }
@@ -132,8 +156,8 @@ _notmuch_message_create_for_document (const void *talloc_owner,
  *
  * Here, 'talloc owner' is an optional talloc context to which the new
  * message will belong. This allows for the caller to not bother
- * calling notmuch_message_destroy on the message, and no that all
- * memory will be reclaimed with 'talloc_owner' is free. The caller
+ * calling notmuch_message_destroy on the message, and know that all
+ * memory will be reclaimed when 'talloc_owner' is freed. The caller
  * still can call notmuch_message_destroy when finished with the
  * message if desired.
  *
@@ -186,15 +210,17 @@ _notmuch_message_create (const void *talloc_owner,
  *
  *     There is already a document with message ID 'message_id' in the
  *     database. The returned message can be used to query/modify the
- *     document.
+ *     document. The message may be a ghost message.
+ *
  *   NOTMUCH_PRIVATE_STATUS_NO_DOCUMENT_FOUND:
  *
  *     No document with 'message_id' exists in the database. The
  *     returned message contains a newly created document (not yet
  *     added to the database) and a document ID that is known not to
- *     exist in the database. The caller can modify the message, and a
- *     call to _notmuch_message_sync will add * the document to the
- *     database.
+ *     exist in the database.  This message is "blank"; that is, it
+ *     contains only a message ID and no other metadata. The caller
+ *     can modify the message, and a call to _notmuch_message_sync
+ *     will add the document to the database.
  *
  * If an error occurs, this function will return NULL and *status
  * will be set as appropriate. (The status pointer argument must
@@ -207,15 +233,20 @@ _notmuch_message_create_for_message_id (notmuch_database_t *notmuch,
 {
     notmuch_message_t *message;
     Xapian::Document doc;
-    Xapian::WritableDatabase *db;
     unsigned int doc_id;
     char *term;
 
-    *status_ret = NOTMUCH_PRIVATE_STATUS_SUCCESS;
-
-    message = notmuch_database_find_message (notmuch, message_id);
+    *status_ret = (notmuch_private_status_t) notmuch_database_find_message (notmuch,
+									    message_id,
+									    &message);
     if (message)
 	return talloc_steal (notmuch, message);
+    else if (*status_ret)
+	return NULL;
+
+    /* If the message ID is too long, substitute its sha1 instead. */
+    if (strlen (message_id) > NOTMUCH_MESSAGE_ID_MAX)
+	message_id = _notmuch_message_id_compressed (message, message_id);
 
     term = talloc_asprintf (NULL, "%s%s",
 			    _find_prefix ("id"), message_id);
@@ -227,7 +258,6 @@ _notmuch_message_create_for_message_id (notmuch_database_t *notmuch,
     if (notmuch->mode == NOTMUCH_DATABASE_MODE_READ_ONLY)
 	INTERNAL_ERROR ("Failure to ensure database is writable.");
 
-    db = static_cast<Xapian::WritableDatabase *> (notmuch->xapian_db);
     try {
 	doc.add_term (term, 0);
 	talloc_free (term);
@@ -236,7 +266,7 @@ _notmuch_message_create_for_message_id (notmuch_database_t *notmuch,
 
 	doc_id = _notmuch_database_generate_doc_id (notmuch);
     } catch (const Xapian::Error &error) {
-	fprintf (stderr, "A Xapian exception occurred creating message: %s\n",
+	_notmuch_database_log(_notmuch_message_database (message), "A Xapian exception occurred creating message: %s\n",
 		 error.get_msg().c_str());
 	notmuch->exception_reported = TRUE;
 	*status_ret = NOTMUCH_PRIVATE_STATUS_XAPIAN_EXCEPTION;
@@ -254,41 +284,199 @@ _notmuch_message_create_for_message_id (notmuch_database_t *notmuch,
     return message;
 }
 
-unsigned int
-_notmuch_message_get_doc_id (notmuch_message_t *message)
-{
-    return message->doc_id;
-}
-
-const char *
-notmuch_message_get_message_id (notmuch_message_t *message)
+static char *
+_notmuch_message_get_term (notmuch_message_t *message,
+			   Xapian::TermIterator &i, Xapian::TermIterator &end,
+			   const char *prefix)
 {
-    Xapian::TermIterator i;
+    int prefix_len = strlen (prefix);
+    char *value;
 
-    if (message->message_id)
-	return message->message_id;
+    i.skip_to (prefix);
 
-    i = message->doc.termlist_begin ();
-    i.skip_to (_find_prefix ("id"));
+    if (i == end)
+	return NULL;
 
-    if (i == message->doc.termlist_end ())
-	INTERNAL_ERROR ("Message with document ID of %d has no message ID.\n",
-			message->doc_id);
+    const std::string &term = *i;
+    if (strncmp (term.c_str(), prefix, prefix_len))
+	return NULL;
 
-    message->message_id = talloc_strdup (message, (*i).c_str () + 1);
+    value = talloc_strdup (message, term.c_str() + prefix_len);
 
 #if DEBUG_DATABASE_SANITY
     i++;
 
-    if (i != message->doc.termlist_end () &&
-	strncmp ((*i).c_str (), _find_prefix ("id"),
-		 strlen (_find_prefix ("id"))) == 0)
-    {
-	INTERNAL_ERROR ("Mail (doc_id: %d) has duplicate message IDs",
-			message->doc_id);
+    if (i != end && strncmp ((*i).c_str (), prefix, prefix_len) == 0) {
+	INTERNAL_ERROR ("Mail (doc_id: %d) has duplicate %s terms: %s and %s\n",
+			message->doc_id, prefix, value,
+			(*i).c_str () + prefix_len);
     }
 #endif
 
+    return value;
+}
+
+static void
+_notmuch_message_ensure_metadata (notmuch_message_t *message, void *field)
+{
+    Xapian::TermIterator i, end;
+
+    if (field && (message->last_view >= message->notmuch->view))
+	return;
+
+    const char *thread_prefix = _find_prefix ("thread"),
+	*tag_prefix = _find_prefix ("tag"),
+	*id_prefix = _find_prefix ("id"),
+	*type_prefix = _find_prefix ("type"),
+	*filename_prefix = _find_prefix ("file-direntry"),
+	*property_prefix = _find_prefix ("property"),
+	*replyto_prefix = _find_prefix ("replyto");
+
+    /* We do this all in a single pass because Xapian decompresses the
+     * term list every time you iterate over it.  Thus, while this is
+     * slightly more costly than looking up individual fields if only
+     * one field of the message object is actually used, it's a huge
+     * win as more fields are used. */
+    for (int count=0; count < 3; count++) {
+	try {
+	    i = message->doc.termlist_begin ();
+	    end = message->doc.termlist_end ();
+
+	    /* Get thread */
+	    if (!message->thread_id)
+		message->thread_id =
+		    _notmuch_message_get_term (message, i, end, thread_prefix);
+
+	    /* Get tags */
+	    assert (strcmp (thread_prefix, tag_prefix) < 0);
+	    if (!message->tag_list) {
+		message->tag_list =
+		    _notmuch_database_get_terms_with_prefix (message, i, end,
+							     tag_prefix);
+		_notmuch_string_list_sort (message->tag_list);
+	    }
+
+	    /* Get id */
+	    assert (strcmp (tag_prefix, id_prefix) < 0);
+	    if (!message->message_id)
+		message->message_id =
+		    _notmuch_message_get_term (message, i, end, id_prefix);
+
+	    /* Get document type */
+	    assert (strcmp (id_prefix, type_prefix) < 0);
+	    if (! NOTMUCH_TEST_BIT (message->lazy_flags, NOTMUCH_MESSAGE_FLAG_GHOST)) {
+		i.skip_to (type_prefix);
+		/* "T" is the prefix "type" fields.  See
+		 * BOOLEAN_PREFIX_INTERNAL. */
+		if (*i == "Tmail")
+		    NOTMUCH_CLEAR_BIT (&message->flags, NOTMUCH_MESSAGE_FLAG_GHOST);
+		else if (*i == "Tghost")
+		    NOTMUCH_SET_BIT (&message->flags, NOTMUCH_MESSAGE_FLAG_GHOST);
+		else
+		    INTERNAL_ERROR ("Message without type term");
+		NOTMUCH_SET_BIT (&message->lazy_flags, NOTMUCH_MESSAGE_FLAG_GHOST);
+	    }
+
+	    /* Get filename list.  Here we get only the terms.  We lazily
+	     * expand them to full file names when needed in
+	     * _notmuch_message_ensure_filename_list. */
+	    assert (strcmp (type_prefix, filename_prefix) < 0);
+	    if (!message->filename_term_list && !message->filename_list)
+		message->filename_term_list =
+		    _notmuch_database_get_terms_with_prefix (message, i, end,
+							     filename_prefix);
+
+
+	    /* Get property terms. Mimic the setup with filenames above */
+	    assert (strcmp (filename_prefix, property_prefix) < 0);
+	    if (!message->property_map && !message->property_term_list)
+		message->property_term_list =
+		    _notmuch_database_get_terms_with_prefix (message, i, end,
+							 property_prefix);
+
+	    /* Get reply to */
+	    assert (strcmp (property_prefix, replyto_prefix) < 0);
+	    if (!message->in_reply_to)
+		message->in_reply_to =
+		    _notmuch_message_get_term (message, i, end, replyto_prefix);
+
+
+	    /* It's perfectly valid for a message to have no In-Reply-To
+	     * header. For these cases, we return an empty string. */
+	    if (!message->in_reply_to)
+		message->in_reply_to = talloc_strdup (message, "");
+
+	    /* all the way without an exception */
+	    break;
+	} catch (const Xapian::DatabaseModifiedError &error) {
+	    notmuch_status_t status = _notmuch_database_reopen (message->notmuch);
+	    if (status != NOTMUCH_STATUS_SUCCESS)
+		INTERNAL_ERROR ("unhandled error from notmuch_database_reopen: %s\n",
+				notmuch_status_to_string (status));
+	} catch (const Xapian::Error &error) {
+	    INTERNAL_ERROR ("A Xapian exception occurred fetching message metadata: %s\n",
+			    error.get_msg().c_str());
+	}
+    }
+    message->last_view = message->notmuch->view;
+}
+
+void
+_notmuch_message_invalidate_metadata (notmuch_message_t *message,
+				      const char *prefix_name)
+{
+    if (strcmp ("thread", prefix_name) == 0) {
+	talloc_free (message->thread_id);
+	message->thread_id = NULL;
+    }
+
+    if (strcmp ("tag", prefix_name) == 0) {
+	talloc_unlink (message, message->tag_list);
+	message->tag_list = NULL;
+    }
+
+    if (strcmp ("type", prefix_name) == 0) {
+	NOTMUCH_CLEAR_BIT (&message->flags, NOTMUCH_MESSAGE_FLAG_GHOST);
+	NOTMUCH_CLEAR_BIT (&message->lazy_flags, NOTMUCH_MESSAGE_FLAG_GHOST);
+    }
+
+    if (strcmp ("file-direntry", prefix_name) == 0) {
+	talloc_free (message->filename_term_list);
+	talloc_free (message->filename_list);
+	message->filename_term_list = message->filename_list = NULL;
+    }
+
+    if (strcmp ("property", prefix_name) == 0) {
+
+	if (message->property_term_list)
+	    talloc_free (message->property_term_list);
+	message->property_term_list = NULL;
+
+	if (message->property_map)
+	    talloc_unlink (message, message->property_map);
+
+	message->property_map = NULL;
+    }
+
+    if (strcmp ("replyto", prefix_name) == 0) {
+	talloc_free (message->in_reply_to);
+	message->in_reply_to = NULL;
+    }
+}
+
+unsigned int
+_notmuch_message_get_doc_id (notmuch_message_t *message)
+{
+    return message->doc_id;
+}
+
+const char *
+notmuch_message_get_message_id (notmuch_message_t *message)
+{
+    _notmuch_message_ensure_metadata (message, message->message_id);
+    if (!message->message_id)
+	INTERNAL_ERROR ("Message with document ID of %u has no message ID.\n",
+			message->doc_id);
     return message->message_id;
 }
 
@@ -304,17 +492,50 @@ _notmuch_message_ensure_message_file (notmuch_message_t *message)
     if (unlikely (filename == NULL))
 	return;
 
-    message->message_file = _notmuch_message_file_open_ctx (message, filename);
+    message->message_file = _notmuch_message_file_open_ctx (
+	_notmuch_message_database (message), message, filename);
 }
 
 const char *
 notmuch_message_get_header (notmuch_message_t *message, const char *header)
 {
+    Xapian::valueno slot = Xapian::BAD_VALUENO;
+
+    /* Fetch header from the appropriate xapian value field if
+     * available */
+    if (strcasecmp (header, "from") == 0)
+	slot = NOTMUCH_VALUE_FROM;
+    else if (strcasecmp (header, "subject") == 0)
+	slot = NOTMUCH_VALUE_SUBJECT;
+    else if (strcasecmp (header, "message-id") == 0)
+	slot = NOTMUCH_VALUE_MESSAGE_ID;
+
+    if (slot != Xapian::BAD_VALUENO) {
+	try {
+	    std::string value = message->doc.get_value (slot);
+
+	    /* If we have NOTMUCH_FEATURE_FROM_SUBJECT_ID_VALUES, then
+	     * empty values indicate empty headers.  If we don't, then
+	     * it could just mean we didn't record the header. */
+	    if ((message->notmuch->features &
+		 NOTMUCH_FEATURE_FROM_SUBJECT_ID_VALUES) ||
+		! value.empty())
+		return talloc_strdup (message, value.c_str ());
+
+	} catch (Xapian::Error &error) {
+	    _notmuch_database_log(_notmuch_message_database (message), "A Xapian exception occurred when reading header: %s\n",
+		     error.get_msg().c_str());
+	    message->notmuch->exception_reported = TRUE;
+	    return NULL;
+	}
+    }
+
+    /* Otherwise fall back to parsing the file */
     _notmuch_message_ensure_message_file (message);
     if (message->message_file == NULL)
 	return NULL;
 
-    return notmuch_message_file_get_header (message->message_file, header);
+    return _notmuch_message_file_get_header (message->message_file, header);
 }
 
 /* Return the message ID from the In-Reply-To header of 'message'.
@@ -327,103 +548,180 @@ notmuch_message_get_header (notmuch_message_t *message, const char *header)
 const char *
 _notmuch_message_get_in_reply_to (notmuch_message_t *message)
 {
-    const char *prefix = _find_prefix ("replyto");
-    int prefix_len = strlen (prefix);
-    Xapian::TermIterator i;
-    std::string in_reply_to;
-
-    if (message->in_reply_to)
-	return message->in_reply_to;
+    _notmuch_message_ensure_metadata (message, message->in_reply_to);
+    return message->in_reply_to;
+}
 
-    i = message->doc.termlist_begin ();
-    i.skip_to (prefix);
+const char *
+notmuch_message_get_thread_id (notmuch_message_t *message)
+{
+    _notmuch_message_ensure_metadata (message, message->thread_id);
+    if (!message->thread_id)
+	INTERNAL_ERROR ("Message with document ID of %u has no thread ID.\n",
+			message->doc_id);
+    return message->thread_id;
+}
 
-    if (i != message->doc.termlist_end ())
-	in_reply_to = *i;
+void
+_notmuch_message_add_reply (notmuch_message_t *message,
+			    notmuch_message_t *reply)
+{
+    _notmuch_message_list_add_message (message->replies, reply);
+}
 
-    /* It's perfectly valid for a message to have no In-Reply-To
-     * header. For these cases, we return an empty string. */
-    if (i == message->doc.termlist_end () ||
-	strncmp (in_reply_to.c_str (), prefix, prefix_len))
-    {
-	message->in_reply_to = talloc_strdup (message, "");
-	return message->in_reply_to;
-    }
+notmuch_messages_t *
+notmuch_message_get_replies (notmuch_message_t *message)
+{
+    return _notmuch_messages_create (message->replies);
+}
 
-    message->in_reply_to = talloc_strdup (message,
-					  in_reply_to.c_str () + prefix_len);
+void
+_notmuch_message_remove_terms (notmuch_message_t *message, const char *prefix)
+{
+    Xapian::TermIterator i;
+    size_t prefix_len = strlen (prefix);
 
-#if DEBUG_DATABASE_SANITY
-    i++;
+    while (1) {
+	i = message->doc.termlist_begin ();
+	i.skip_to (prefix);
 
-    in_reply_to = *i;
+	/* Terminate loop when no terms remain with desired prefix. */
+	if (i == message->doc.termlist_end () ||
+	    strncmp ((*i).c_str (), prefix, prefix_len))
+	    break;
 
-    if (i != message->doc.termlist_end () &&
-	strncmp ((*i).c_str (), prefix, prefix_len) == 0)
-    {
-       INTERNAL_ERROR ("Message %s has duplicate In-Reply-To IDs: %s and %s\n",
-			notmuch_message_get_message_id (message),
-			message->in_reply_to,
-			(*i).c_str () + prefix_len);
+	try {
+	    message->doc.remove_term ((*i));
+	    message->modified = TRUE;
+	} catch (const Xapian::InvalidArgumentError) {
+	    /* Ignore failure to remove non-existent term. */
+	}
     }
-#endif
+}
 
-    return message->in_reply_to;
+/* Return true if p points at "new" or "cur". */
+static bool is_maildir (const char *p)
+{
+    return strcmp (p, "cur") == 0 || strcmp (p, "new") == 0;
 }
 
-const char *
-notmuch_message_get_thread_id (notmuch_message_t *message)
+/* Add "folder:" term for directory. */
+static notmuch_status_t
+_notmuch_message_add_folder_terms (notmuch_message_t *message,
+				   const char *directory)
 {
-    const char *prefix = _find_prefix ("thread");
-    Xapian::TermIterator i;
-    std::string id;
+    char *folder, *last;
+
+    folder = talloc_strdup (NULL, directory);
+    if (! folder)
+	return NOTMUCH_STATUS_OUT_OF_MEMORY;
+
+    /*
+     * If the message file is in a leaf directory named "new" or
+     * "cur", presume maildir and index the parent directory. Thus a
+     * "folder:" prefix search matches messages in the specified
+     * maildir folder, i.e. in the specified directory and its "new"
+     * and "cur" subdirectories.
+     *
+     * Note that this means the "folder:" prefix can't be used for
+     * distinguishing between message files in "new" or "cur". The
+     * "path:" prefix needs to be used for that.
+     *
+     * Note the deliberate difference to _filename_is_in_maildir(). We
+     * don't want to index different things depending on the existence
+     * or non-existence of all maildir sibling directories "new",
+     * "cur", and "tmp". Doing so would be surprising, and difficult
+     * for the user to fix in case all subdirectories were not in
+     * place during indexing.
+     */
+    last = strrchr (folder, '/');
+    if (last) {
+	if (is_maildir (last + 1))
+	    *last = '\0';
+    } else if (is_maildir (folder)) {
+	*folder = '\0';
+    }
 
-    /* This code is written with the assumption that "thread" has a
-     * single-character prefix. */
-    assert (strlen (prefix) == 1);
+    _notmuch_message_add_term (message, "folder", folder);
 
-    if (message->thread_id)
-	return message->thread_id;
+    talloc_free (folder);
 
-    i = message->doc.termlist_begin ();
-    i.skip_to (prefix);
+    return NOTMUCH_STATUS_SUCCESS;
+}
 
-    if (i != message->doc.termlist_end ())
-	id = *i;
+#define RECURSIVE_SUFFIX "/**"
 
-    if (i == message->doc.termlist_end () || id[0] != *prefix)
-	INTERNAL_ERROR ("Message with document ID of %d has no thread ID.\n",
-			message->doc_id);
+/* Add "path:" terms for directory. */
+static notmuch_status_t
+_notmuch_message_add_path_terms (notmuch_message_t *message,
+				 const char *directory)
+{
+    /* Add exact "path:" term. */
+    _notmuch_message_add_term (message, "path", directory);
 
-    message->thread_id = talloc_strdup (message, id.c_str () + 1);
+    if (strlen (directory)) {
+	char *path, *p;
 
-#if DEBUG_DATABASE_SANITY
-    i++;
-    id = *i;
+	path = talloc_asprintf (NULL, "%s%s", directory, RECURSIVE_SUFFIX);
+	if (! path)
+	    return NOTMUCH_STATUS_OUT_OF_MEMORY;
 
-    if (i != message->doc.termlist_end () && id[0] == *prefix)
-    {
-	INTERNAL_ERROR ("Message %s has duplicate thread IDs: %s and %s\n",
-			notmuch_message_get_message_id (message),
-			message->thread_id,
-			id.c_str () + 1);
+	/* Add recursive "path:" terms for directory and all parents. */
+	for (p = path + strlen (path) - 1; p > path; p--) {
+	    if (*p == '/') {
+		strcpy (p, RECURSIVE_SUFFIX);
+		_notmuch_message_add_term (message, "path", path);
+	    }
+	}
+
+	talloc_free (path);
     }
-#endif
 
-    return message->thread_id;
-}
+    /* Recursive all-matching path:** for consistency. */
+    _notmuch_message_add_term (message, "path", "**");
 
-void
-_notmuch_message_add_reply (notmuch_message_t *message,
-			    notmuch_message_node_t *reply)
-{
-    _notmuch_message_list_append (message->replies, reply);
+    return NOTMUCH_STATUS_SUCCESS;
 }
 
-notmuch_messages_t *
-notmuch_message_get_replies (notmuch_message_t *message)
+/* Add directory based terms for all filenames of the message. */
+static notmuch_status_t
+_notmuch_message_add_directory_terms (void *ctx, notmuch_message_t *message)
 {
-    return _notmuch_messages_create (message->replies);
+    const char *direntry_prefix = _find_prefix ("file-direntry");
+    int direntry_prefix_len = strlen (direntry_prefix);
+    Xapian::TermIterator i = message->doc.termlist_begin ();
+    notmuch_status_t status = NOTMUCH_STATUS_SUCCESS;
+
+    for (i.skip_to (direntry_prefix); i != message->doc.termlist_end (); i++) {
+	unsigned int directory_id;
+	const char *direntry, *directory;
+	char *colon;
+	const std::string &term = *i;
+
+	/* Terminate loop at first term without desired prefix. */
+	if (strncmp (term.c_str (), direntry_prefix, direntry_prefix_len))
+	    break;
+
+	/* Indicate that there are filenames remaining. */
+	status = NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID;
+
+	direntry = term.c_str ();
+	direntry += direntry_prefix_len;
+
+	directory_id = strtol (direntry, &colon, 10);
+
+	if (colon == NULL || *colon != ':')
+	    INTERNAL_ERROR ("malformed direntry");
+
+	directory = _notmuch_database_get_directory_path (ctx,
+							  message->notmuch,
+							  directory_id);
+
+	_notmuch_message_add_folder_terms (message, directory);
+	_notmuch_message_add_path_terms (message, directory);
+    }
+
+    return status;
 }
 
 /* Add an additional 'filename' for 'message'.
@@ -434,66 +732,111 @@ notmuch_status_t
 _notmuch_message_add_filename (notmuch_message_t *message,
 			       const char *filename)
 {
+    const char *relative, *directory;
     notmuch_status_t status;
     void *local = talloc_new (message);
     char *direntry;
 
-    if (message->filename_list) {
-	_notmuch_filename_list_destroy (message->filename_list);
-	message->filename_list = NULL;
-    }
-
     if (filename == NULL)
 	INTERNAL_ERROR ("Message filename cannot be NULL.");
 
-    status = _notmuch_database_filename_to_direntry (local,
-						     message->notmuch,
-						     filename, &direntry);
+    if (! (message->notmuch->features & NOTMUCH_FEATURE_FILE_TERMS) ||
+	! (message->notmuch->features & NOTMUCH_FEATURE_BOOL_FOLDER))
+	return NOTMUCH_STATUS_UPGRADE_REQUIRED;
+
+    relative = _notmuch_database_relative_path (message->notmuch, filename);
+
+    status = _notmuch_database_split_path (local, relative, &directory, NULL);
+    if (status)
+	return status;
+
+    status = _notmuch_database_filename_to_direntry (
+	local, message->notmuch, filename, NOTMUCH_FIND_CREATE, &direntry);
     if (status)
 	return status;
 
+    /* New file-direntry allows navigating to this message with
+     * notmuch_directory_get_child_files() . */
     _notmuch_message_add_term (message, "file-direntry", direntry);
 
+    _notmuch_message_add_folder_terms (message, directory);
+    _notmuch_message_add_path_terms (message, directory);
+
     talloc_free (local);
 
     return NOTMUCH_STATUS_SUCCESS;
 }
 
-/* Change a particular filename for 'message' from 'old_filename' to
- * 'new_filename'
+/* Remove a particular 'filename' from 'message'.
  *
  * This change will not be reflected in the database until the next
  * call to _notmuch_message_sync.
- */
-static notmuch_status_t
-_notmuch_message_rename (notmuch_message_t *message,
-			 const char *old_filename,
-			 const char *new_filename)
+ *
+ * If this message still has other filenames, returns
+ * NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID.
+ *
+ * Note: This function does not remove a document from the database,
+ * even if the specified filename is the only filename for this
+ * message. For that functionality, see
+ * notmuch_database_remove_message. */
+notmuch_status_t
+_notmuch_message_remove_filename (notmuch_message_t *message,
+				  const char *filename)
 {
     void *local = talloc_new (message);
     char *direntry;
     notmuch_private_status_t private_status;
     notmuch_status_t status;
 
-    status = _notmuch_message_add_filename (message, new_filename);
-    if (status)
-	return status;
+    if (! (message->notmuch->features & NOTMUCH_FEATURE_FILE_TERMS) ||
+	! (message->notmuch->features & NOTMUCH_FEATURE_BOOL_FOLDER))
+	return NOTMUCH_STATUS_UPGRADE_REQUIRED;
 
-    status = _notmuch_database_filename_to_direntry (local, message->notmuch,
-						     old_filename, &direntry);
-    if (status)
+    status = _notmuch_database_filename_to_direntry (
+	local, message->notmuch, filename, NOTMUCH_FIND_LOOKUP, &direntry);
+    if (status || !direntry)
 	return status;
 
+    /* Unlink this file from its parent directory. */
     private_status = _notmuch_message_remove_term (message,
 						   "file-direntry", direntry);
     status = COERCE_STATUS (private_status,
 			    "Unexpected error from _notmuch_message_remove_term");
+    if (status)
+	return status;
+
+    /* Re-synchronize "folder:" and "path:" terms for this message. */
+
+    /* Remove all "folder:" terms. */
+    _notmuch_message_remove_terms (message, _find_prefix ("folder"));
+
+    /* Remove all "path:" terms. */
+    _notmuch_message_remove_terms (message, _find_prefix ("path"));
+
+    /* Add back terms for all remaining filenames of the message. */
+    status = _notmuch_message_add_directory_terms (local, message);
 
     talloc_free (local);
 
     return status;
 }
 
+/* Upgrade the "folder:" prefix from V1 to V2. */
+#define FOLDER_PREFIX_V1       "XFOLDER"
+#define ZFOLDER_PREFIX_V1      "Z" FOLDER_PREFIX_V1
+void
+_notmuch_message_upgrade_folder (notmuch_message_t *message)
+{
+    /* Remove all old "folder:" terms. */
+    _notmuch_message_remove_terms (message, FOLDER_PREFIX_V1);
+
+    /* Remove all old "folder:" stemmed terms. */
+    _notmuch_message_remove_terms (message, ZFOLDER_PREFIX_V1);
+
+    /* Add new boolean "folder:" and "path:" terms. */
+    _notmuch_message_add_directory_terms (message, message);
+}
+
 char *
 _notmuch_message_talloc_copy_data (notmuch_message_t *message)
 {
@@ -504,57 +847,48 @@ void
 _notmuch_message_clear_data (notmuch_message_t *message)
 {
     message->doc.set_data ("");
+    message->modified = TRUE;
 }
 
 static void
 _notmuch_message_ensure_filename_list (notmuch_message_t *message)
 {
-    const char *prefix = _find_prefix ("file-direntry");
-    int prefix_len = strlen (prefix);
-    Xapian::TermIterator i;
+    notmuch_string_node_t *node;
 
     if (message->filename_list)
 	return;
 
-    message->filename_list = _notmuch_filename_list_create (message);
+    _notmuch_message_ensure_metadata (message, message->filename_term_list);
 
-    i = message->doc.termlist_begin ();
-    i.skip_to (prefix);
+    message->filename_list = _notmuch_string_list_create (message);
+    node = message->filename_term_list->head;
 
-    if (i == message->doc.termlist_end () ||
-	strncmp ((*i).c_str (), prefix, prefix_len))
-    {
+    if (!node) {
 	/* A message document created by an old version of notmuch
 	 * (prior to rename support) will have the filename in the
 	 * data of the document rather than as a file-direntry term.
 	 *
 	 * It would be nice to do the upgrade of the document directly
 	 * here, but the database is likely open in read-only mode. */
-	const char *data;
 
-	data = message->doc.get_data ().c_str ();
+	std::string datastr = message->doc.get_data ();
+	const char *data = datastr.c_str ();
 
 	if (data == NULL)
 	    INTERNAL_ERROR ("message with no filename");
 
-	_notmuch_filename_list_add_filename (message->filename_list, data);
+	_notmuch_string_list_append (message->filename_list, data);
 
 	return;
     }
 
-    for (; i != message->doc.termlist_end (); i++) {
+    for (; node; node = node->next) {
 	void *local = talloc_new (message);
 	const char *db_path, *directory, *basename, *filename;
 	char *colon, *direntry = NULL;
 	unsigned int directory_id;
 
-	/* Terminate loop at first term without desired prefix. */
-	if (strncmp ((*i).c_str (), prefix, prefix_len))
-	    break;
-
-	direntry = talloc_strdup (local, (*i).c_str ());
-
-	direntry += prefix_len;
+	direntry = node->string;
 
 	directory_id = strtol (direntry, &colon, 10);
 
@@ -578,11 +912,13 @@ _notmuch_message_ensure_filename_list (notmuch_message_t *message)
 	    filename = talloc_asprintf (message, "%s/%s",
 					db_path, basename);
 
-	_notmuch_filename_list_add_filename (message->filename_list,
-					     filename);
+	_notmuch_string_list_append (message->filename_list, filename);
 
 	talloc_free (local);
     }
+
+    talloc_free (message->filename_term_list);
+    message->filename_term_list = NULL;
 }
 
 const char *
@@ -594,12 +930,12 @@ notmuch_message_get_filename (notmuch_message_t *message)
 	return NULL;
 
     if (message->filename_list->head == NULL ||
-	message->filename_list->head->filename == NULL)
+	message->filename_list->head->string == NULL)
     {
 	INTERNAL_ERROR ("message with no filename");
     }
 
-    return message->filename_list->head->filename;
+    return message->filename_list->head->string;
 }
 
 notmuch_filenames_t *
@@ -614,7 +950,11 @@ notmuch_bool_t
 notmuch_message_get_flag (notmuch_message_t *message,
 			  notmuch_message_flag_t flag)
 {
-    return message->flags & (1 << flag);
+    if (flag == NOTMUCH_MESSAGE_FLAG_GHOST &&
+	! NOTMUCH_TEST_BIT (message->lazy_flags, flag))
+	_notmuch_message_ensure_metadata (message, NULL);
+
+    return NOTMUCH_TEST_BIT (message->flags, flag);
 }
 
 void
@@ -622,9 +962,10 @@ notmuch_message_set_flag (notmuch_message_t *message,
 			  notmuch_message_flag_t flag, notmuch_bool_t enable)
 {
     if (enable)
-	message->flags |= (1 << flag);
+	NOTMUCH_SET_BIT (&message->flags, flag);
     else
-	message->flags &= ~(1 << flag);
+	NOTMUCH_CLEAR_BIT (&message->flags, flag);
+    NOTMUCH_SET_BIT (&message->lazy_flags, flag);
 }
 
 time_t
@@ -635,30 +976,46 @@ notmuch_message_get_date (notmuch_message_t *message)
     try {
 	value = message->doc.get_value (NOTMUCH_VALUE_TIMESTAMP);
     } catch (Xapian::Error &error) {
-	INTERNAL_ERROR ("Failed to read timestamp value from document.");
+	_notmuch_database_log(_notmuch_message_database (message), "A Xapian exception occurred when reading date: %s\n",
+		 error.get_msg().c_str());
+	message->notmuch->exception_reported = TRUE;
 	return 0;
     }
 
+    if (value.empty ())
+	/* sortable_unserialise is undefined on empty string */
+	return 0;
     return Xapian::sortable_unserialise (value);
 }
 
 notmuch_tags_t *
 notmuch_message_get_tags (notmuch_message_t *message)
 {
-    Xapian::TermIterator i, end;
-    i = message->doc.termlist_begin();
-    end = message->doc.termlist_end();
-    return _notmuch_convert_tags(message, i, end);
+    notmuch_tags_t *tags;
+
+    _notmuch_message_ensure_metadata (message, message->tag_list);
+
+    tags = _notmuch_tags_create (message, message->tag_list);
+    /* _notmuch_tags_create steals the reference to the tag_list, but
+     * in this case it's still used by the message, so we add an
+     * *additional* talloc reference to the list.  As a result, it's
+     * possible to modify the message tags (which talloc_unlink's the
+     * current list from the message) while still iterating because
+     * the iterator will keep the current list alive. */
+    if (!talloc_reference (message, message->tag_list))
+	return NULL;
+
+    return tags;
 }
 
 const char *
-notmuch_message_get_author (notmuch_message_t *message)
+_notmuch_message_get_author (notmuch_message_t *message)
 {
     return message->author;
 }
 
 void
-notmuch_message_set_author (notmuch_message_t *message,
+_notmuch_message_set_author (notmuch_message_t *message,
 			    const char *author)
 {
     if (message->author)
@@ -668,20 +1025,41 @@ notmuch_message_set_author (notmuch_message_t *message,
 }
 
 void
-_notmuch_message_set_date (notmuch_message_t *message,
-			   const char *date)
+_notmuch_message_set_header_values (notmuch_message_t *message,
+				    const char *date,
+				    const char *from,
+				    const char *subject)
 {
     time_t time_value;
 
     /* GMime really doesn't want to see a NULL date, so protect its
      * sensibilities. */
-    if (date == NULL || *date == '\0')
+    if (date == NULL || *date == '\0') {
 	time_value = 0;
-    else
+    } else {
 	time_value = g_mime_utils_header_decode_date (date, NULL);
+	/*
+	 * Workaround for https://bugzilla.gnome.org/show_bug.cgi?id=779923
+	 */
+	if (time_value < 0)
+	    time_value = 0;
+    }
 
     message->doc.add_value (NOTMUCH_VALUE_TIMESTAMP,
 			    Xapian::sortable_serialise (time_value));
+    message->doc.add_value (NOTMUCH_VALUE_FROM, from);
+    message->doc.add_value (NOTMUCH_VALUE_SUBJECT, subject);
+    message->modified = TRUE;
+}
+
+/* Upgrade a message to support NOTMUCH_FEATURE_LAST_MOD.  The caller
+ * must call _notmuch_message_sync. */
+void
+_notmuch_message_upgrade_last_mod (notmuch_message_t *message)
+{
+    /* _notmuch_message_sync will update the last modification
+     * revision; we just have to ask it to. */
+    message->modified = TRUE;
 }
 
 /* Synchronize changes made to message->doc out into the database. */
@@ -693,8 +1071,128 @@ _notmuch_message_sync (notmuch_message_t *message)
     if (message->notmuch->mode == NOTMUCH_DATABASE_MODE_READ_ONLY)
 	return;
 
+    if (! message->modified)
+	return;
+
+    /* Update the last modification of this message. */
+    if (message->notmuch->features & NOTMUCH_FEATURE_LAST_MOD)
+	/* sortable_serialise gives a reasonably compact encoding,
+	 * which directly translates to reduced IO when scanning the
+	 * value stream.  Since it's built for doubles, we only get 53
+	 * effective bits, but that's still enough for the database to
+	 * last a few centuries at 1 million revisions per second. */
+	message->doc.add_value (NOTMUCH_VALUE_LAST_MOD,
+				Xapian::sortable_serialise (
+				    _notmuch_database_new_revision (
+					message->notmuch)));
+
     db = static_cast <Xapian::WritableDatabase *> (message->notmuch->xapian_db);
     db->replace_document (message->doc_id, message->doc);
+    message->modified = FALSE;
+}
+
+/* Delete a message document from the database, leaving a ghost
+ * message in its place */
+notmuch_status_t
+_notmuch_message_delete (notmuch_message_t *message)
+{
+    notmuch_status_t status;
+    Xapian::WritableDatabase *db;
+    const char *mid, *tid, *query_string;
+    notmuch_message_t *ghost;
+    notmuch_private_status_t private_status;
+    notmuch_database_t *notmuch;
+    notmuch_query_t *query;
+    unsigned int count = 0;
+    notmuch_bool_t is_ghost;
+
+    mid = notmuch_message_get_message_id (message);
+    tid = notmuch_message_get_thread_id (message);
+    notmuch = message->notmuch;
+
+    status = _notmuch_database_ensure_writable (message->notmuch);
+    if (status)
+	return status;
+
+    db = static_cast <Xapian::WritableDatabase *> (notmuch->xapian_db);
+    db->delete_document (message->doc_id);
+
+    /* if this was a ghost to begin with, we are done */
+    private_status = _notmuch_message_has_term (message, "type", "ghost", &is_ghost);
+    if (private_status)
+	return COERCE_STATUS (private_status,
+			      "Error trying to determine whether message was a ghost");
+    if (is_ghost)
+	return NOTMUCH_STATUS_SUCCESS;
+
+    query_string = talloc_asprintf (message, "thread:%s", tid);
+    query = notmuch_query_create (notmuch, query_string);
+    if (query == NULL)
+	return NOTMUCH_STATUS_OUT_OF_MEMORY;
+    status = notmuch_query_count_messages_st (query, &count);
+    if (status) {
+	notmuch_query_destroy (query);
+	return status;
+    }
+
+    if (count > 0) {
+	/* reintroduce a ghost in its place because there are still
+	 * other active messages in this thread: */
+	ghost = _notmuch_message_create_for_message_id (notmuch, mid, &private_status);
+	if (private_status == NOTMUCH_PRIVATE_STATUS_NO_DOCUMENT_FOUND) {
+	    private_status = _notmuch_message_initialize_ghost (ghost, tid);
+	    if (! private_status)
+		_notmuch_message_sync (ghost);
+	} else if (private_status == NOTMUCH_PRIVATE_STATUS_SUCCESS) {
+	    /* this is deeply weird, and we should not have gotten
+	       into this state.  is there a better error message to
+	       return here? */
+	    status = NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID;
+	}
+
+	notmuch_message_destroy (ghost);
+	status = COERCE_STATUS (private_status, "Error converting to ghost message");
+    } else {
+	/* the thread is empty; drop all ghost messages from it */
+	notmuch_messages_t *messages;
+	status = _notmuch_query_search_documents (query,
+						  "ghost",
+						  &messages);
+	if (status == NOTMUCH_STATUS_SUCCESS) {
+	    notmuch_status_t last_error = NOTMUCH_STATUS_SUCCESS;
+	    while (notmuch_messages_valid (messages)) {
+		message = notmuch_messages_get (messages);
+		status = _notmuch_message_delete (message);
+		if (status) /* we'll report the last failure we see;
+			     * if there is more than one failure, we
+			     * forget about previous ones */
+		    last_error = status;
+		notmuch_message_destroy (message);
+		notmuch_messages_move_to_next (messages);
+	    }
+	    status = last_error;
+	}
+    }
+    notmuch_query_destroy (query);
+    return status;
+}
+
+/* Transform a blank message into a ghost message.  The caller must
+ * _notmuch_message_sync the message. */
+notmuch_private_status_t
+_notmuch_message_initialize_ghost (notmuch_message_t *message,
+				   const char *thread_id)
+{
+    notmuch_private_status_t status;
+
+    status = _notmuch_message_add_term (message, "type", "ghost");
+    if (status)
+	return status;
+    status = _notmuch_message_add_term (message, "thread", thread_id);
+    if (status)
+	return status;
+
+    return NOTMUCH_PRIVATE_STATUS_SUCCESS;
 }
 
 /* Ensure that 'message' is not holding any file object open. Future
@@ -705,7 +1203,7 @@ void
 _notmuch_message_close (notmuch_message_t *message)
 {
     if (message->message_file) {
-	notmuch_message_file_close (message->message_file);
+	_notmuch_message_file_close (message->message_file);
 	message->message_file = NULL;
     }
 }
@@ -735,15 +1233,18 @@ _notmuch_message_add_term (notmuch_message_t *message,
 	return NOTMUCH_PRIVATE_STATUS_TERM_TOO_LONG;
 
     message->doc.add_term (term, 0);
+    message->modified = TRUE;
 
     talloc_free (term);
 
+    _notmuch_message_invalidate_metadata (message, prefix_name);
+
     return NOTMUCH_PRIVATE_STATUS_SUCCESS;
 }
 
 /* Parse 'text' and add a term to 'message' for each parsed word. Each
  * term will be added both prefixed (if prefix_name is not NULL) and
- * also unprefixed). */
+ * also non-prefixed). */
 notmuch_private_status_t
 _notmuch_message_gen_terms (notmuch_message_t *message,
 			    const char *prefix_name,
@@ -759,10 +1260,19 @@ _notmuch_message_gen_terms (notmuch_message_t *message,
     if (prefix_name) {
 	const char *prefix = _find_prefix (prefix_name);
 
+	term_gen->set_termpos (message->termpos);
 	term_gen->index_text (text, 1, prefix);
+	/* Create a gap between this an the next terms so they don't
+	 * appear to be a phrase. */
+	message->termpos = term_gen->get_termpos () + 100;
+
+	_notmuch_message_invalidate_metadata (message, prefix_name);
     }
 
+    term_gen->set_termpos (message->termpos);
     term_gen->index_text (text);
+    /* Create a term gap, as above. */
+    message->termpos = term_gen->get_termpos () + 100;
 
     return NOTMUCH_PRIVATE_STATUS_SUCCESS;
 }
@@ -792,8 +1302,9 @@ _notmuch_message_remove_term (notmuch_message_t *message,
 
     try {
 	message->doc.remove_term (term);
+	message->modified = TRUE;
     } catch (const Xapian::InvalidArgumentError) {
-	/* We'll let the philosopher's try to wrestle with the
+	/* We'll let the philosophers try to wrestle with the
 	 * question of whether failing to remove that which was not
 	 * there in the first place is failure. For us, we'll silently
 	 * consider it all good. */
@@ -801,9 +1312,46 @@ _notmuch_message_remove_term (notmuch_message_t *message,
 
     talloc_free (term);
 
+    _notmuch_message_invalidate_metadata (message, prefix_name);
+
     return NOTMUCH_PRIVATE_STATUS_SUCCESS;
 }
 
+notmuch_private_status_t
+_notmuch_message_has_term (notmuch_message_t *message,
+			   const char *prefix_name,
+			   const char *value,
+			   notmuch_bool_t *result)
+{
+    char *term;
+    notmuch_bool_t out = FALSE;
+    notmuch_private_status_t status = NOTMUCH_PRIVATE_STATUS_SUCCESS;
+
+    if (value == NULL)
+	return NOTMUCH_PRIVATE_STATUS_NULL_POINTER;
+
+    term = talloc_asprintf (message, "%s%s",
+			    _find_prefix (prefix_name), value);
+
+    if (strlen (term) > NOTMUCH_TERM_MAX)
+	return NOTMUCH_PRIVATE_STATUS_TERM_TOO_LONG;
+
+    try {
+	/* Look for the exact term */
+	Xapian::TermIterator i = message->doc.termlist_begin ();
+	i.skip_to (term);
+	if (i != message->doc.termlist_end () &&
+	    !strcmp ((*i).c_str (), term))
+	    out = TRUE;
+    } catch (Xapian::Error &error) {
+	status = NOTMUCH_PRIVATE_STATUS_XAPIAN_EXCEPTION;
+    }
+    talloc_free (term);
+
+    *result = out;
+    return status;
+}
+
 notmuch_status_t
 notmuch_message_add_tag (notmuch_message_t *message, const char *tag)
 {
@@ -860,13 +1408,54 @@ notmuch_message_remove_tag (notmuch_message_t *message, const char *tag)
     return NOTMUCH_STATUS_SUCCESS;
 }
 
+/* Is the given filename within a maildir directory?
+ *
+ * Specifically, is the final directory component of 'filename' either
+ * "cur" or "new". If so, return a pointer to that final directory
+ * component within 'filename'. If not, return NULL.
+ *
+ * A non-NULL return value is guaranteed to be a valid string pointer
+ * pointing to the characters "new/" or "cur/", (but not
+ * NUL-terminated).
+ */
+static const char *
+_filename_is_in_maildir (const char *filename)
+{
+    const char *slash, *dir = NULL;
+
+    /* Find the last '/' separating directory from filename. */
+    slash = strrchr (filename, '/');
+    if (slash == NULL)
+	return NULL;
+
+    /* Jump back 4 characters to where the previous '/' will be if the
+     * directory is named "cur" or "new". */
+    if (slash - filename < 4)
+	return NULL;
+
+    slash -= 4;
+
+    if (*slash != '/')
+	return NULL;
+
+    dir = slash + 1;
+
+    if (STRNCMP_LITERAL (dir, "cur/") == 0 ||
+	STRNCMP_LITERAL (dir, "new/") == 0)
+    {
+	return dir;
+    }
+
+    return NULL;
+}
+
 notmuch_status_t
 notmuch_message_maildir_flags_to_tags (notmuch_message_t *message)
 {
     const char *flags;
     notmuch_status_t status;
     notmuch_filenames_t *filenames;
-    const char *filename;
+    const char *filename, *dir;
     char *combined_flags = talloc_strdup (message, "");
     unsigned i;
     int seen_maildir_info = 0;
@@ -876,15 +1465,25 @@ notmuch_message_maildir_flags_to_tags (notmuch_message_t *message)
 	 notmuch_filenames_move_to_next (filenames))
     {
 	filename = notmuch_filenames_get (filenames);
+	dir = _filename_is_in_maildir (filename);
 
-	flags = strstr (filename, ":2,");
-	if (! flags)
+	if (! dir)
 	    continue;
 
-	seen_maildir_info = 1;
-	flags += 3;
-
-	combined_flags = talloc_strdup_append (combined_flags, flags);
+	flags = strstr (filename, ":2,");
+	if (flags) {
+	    seen_maildir_info = 1;
+	    flags += 3;
+	    combined_flags = talloc_strdup_append (combined_flags, flags);
+	} else if (STRNCMP_LITERAL (dir, "new/") == 0) {
+	    /* Messages are delivered to new/ with no "info" part, but
+	     * they effectively have default maildir flags.  According
+	     * to the spec, we should ignore the info part for
+	     * messages in new/, but some MUAs (mutt) can set maildir
+	     * flags on messages in new/, so we're liberal in what we
+	     * accept. */
+	    seen_maildir_info = 1;
+	}
     }
 
     /* If none of the filenames have any maildir info field (not even
@@ -899,7 +1498,7 @@ notmuch_message_maildir_flags_to_tags (notmuch_message_t *message)
 
     for (i = 0; i < ARRAY_SIZE(flag2tag); i++) {
 	if ((strchr (combined_flags, flag2tag[i].flag) != NULL)
-	    ^ 
+	    ^
 	    flag2tag[i].inverse)
 	{
 	    status = notmuch_message_add_tag (message, flag2tag[i].tag);
@@ -916,47 +1515,6 @@ notmuch_message_maildir_flags_to_tags (notmuch_message_t *message)
     return status;
 }
 
-/* Is the given filename within a maildir directory?
- *
- * Specifically, is the final directory component of 'filename' either
- * "cur" or "new". If so, return a pointer to that final directory
- * component within 'filename'. If not, return NULL.
- *
- * A non-NULL return value is guaranteed to be a valid string pointer
- * pointing to the characters "new/" or "cur/", (but not
- * NUL-terminated).
- */
-static const char *
-_filename_is_in_maildir (const char *filename)
-{
-    const char *slash, *dir = NULL;
-
-    /* Find the last '/' separating directory from filename. */
-    slash = strrchr (filename, '/');
-    if (slash == NULL)
-	return NULL;
-
-    /* Jump back 4 characters to where the previous '/' will be if the
-     * directory is named "cur" or "new". */
-    if (slash - filename < 4)
-	return NULL;
-
-    slash -= 4;
-
-    if (*slash != '/')
-	return NULL;
-
-    dir = slash + 1;
-
-    if (STRNCMP_LITERAL (dir, "cur/") == 0 ||
-	STRNCMP_LITERAL (dir, "new/") == 0)
-    {
-	return dir;
-    }
-
-    return NULL;
-}
-
 /* From the set of tags on 'message' and the flag2tag table, compute a
  * set of maildir-flag actions to be taken, (flags that should be
  * either set or cleared).
@@ -1016,7 +1574,9 @@ _get_maildir_flag_actions (notmuch_message_t *message,
  * compute the new maildir filename.
  *
  * If the existing filename is in the directory "new", the new
- * filename will be in the directory "cur".
+ * filename will be in the directory "cur", except for the case when
+ * no flags are changed and the existing filename does not contain
+ * maildir info (starting with ",2:").
  *
  * After a sequence of ":2," in the filename, any subsequent
  * single-character flags will be added or removed according to the
@@ -1039,6 +1599,7 @@ _new_maildir_filename (void *ctx,
     char *filename_new, *dir;
     char flag_map[128];
     int flags_in_map = 0;
+    notmuch_bool_t flags_changed = FALSE;
     unsigned int i;
     char *s;
 
@@ -1049,8 +1610,6 @@ _new_maildir_filename (void *ctx,
     if (info == NULL) {
 	info = filename + strlen(filename);
     } else {
-	flags = info + 3;
-
 	/* Loop through existing flags in filename. */
 	for (flags = info + 3, last_flag = 0;
 	     *flags;
@@ -1081,6 +1640,7 @@ _new_maildir_filename (void *ctx,
 	if (flag_map[flag] == 0) {
 	    flag_map[flag] = 1;
 	    flags_in_map++;
+	    flags_changed = TRUE;
 	}
     }
 
@@ -1089,9 +1649,16 @@ _new_maildir_filename (void *ctx,
 	if (flag_map[flag]) {
 	    flag_map[flag] = 0;
 	    flags_in_map--;
+	    flags_changed = TRUE;
 	}
     }
 
+    /* Messages in new/ without maildir info can be kept in new/ if no
+     * flags have changed. */
+    dir = (char *) _filename_is_in_maildir (filename);
+    if (dir && STRNCMP_LITERAL (dir, "new/") == 0 && !*info && !flags_changed)
+	return talloc_strdup (ctx, filename);
+
     filename_new = (char *) talloc_size (ctx,
 					 info - filename +
 					 strlen (":2,") + flags_in_map + 1);
@@ -1154,8 +1721,17 @@ notmuch_message_tags_to_maildir_flags (notmuch_message_t *message)
 	    if (err)
 		continue;
 
-	    new_status = _notmuch_message_rename (message,
-						  filename, filename_new);
+	    new_status = _notmuch_message_remove_filename (message,
+							   filename);
+	    /* Hold on to only the first error. */
+	    if (! status && new_status
+		&& new_status != NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID) {
+		status = new_status;
+		continue;
+	    }
+
+	    new_status = _notmuch_message_add_filename (message,
+							filename_new);
 	    /* Hold on to only the first error. */
 	    if (! status && new_status) {
 		status = new_status;
@@ -1171,7 +1747,7 @@ notmuch_message_tags_to_maildir_flags (notmuch_message_t *message)
     talloc_free (to_set);
     talloc_free (to_clear);
 
-    return NOTMUCH_STATUS_SUCCESS;
+    return status;
 }
 
 notmuch_status_t
@@ -1202,6 +1778,7 @@ notmuch_message_remove_all_tags (notmuch_message_t *message)
     if (! message->frozen)
 	_notmuch_message_sync (message);
 
+    talloc_free (tags);
     return NOTMUCH_STATUS_SUCCESS;
 }
 
@@ -1243,3 +1820,55 @@ notmuch_message_destroy (notmuch_message_t *message)
 {
     talloc_free (message);
 }
+
+notmuch_database_t *
+_notmuch_message_database (notmuch_message_t *message)
+{
+    return message->notmuch;
+}
+
+static void
+_notmuch_message_ensure_property_map (notmuch_message_t *message)
+{
+    notmuch_string_node_t *node;
+
+    if (message->property_map)
+	return;
+
+    _notmuch_message_ensure_metadata (message, message->property_term_list);
+
+    message->property_map = _notmuch_string_map_create (message);
+
+    for (node = message->property_term_list->head; node; node = node->next) {
+	const char *key;
+	char *value;
+
+	value = index(node->string, '=');
+	if (!value)
+	    INTERNAL_ERROR ("malformed property term");
+
+	*value = '\0';
+	value++;
+	key = node->string;
+
+	_notmuch_string_map_append (message->property_map, key, value);
+
+    }
+
+    talloc_free (message->property_term_list);
+    message->property_term_list = NULL;
+}
+
+notmuch_string_map_t *
+_notmuch_message_property_map (notmuch_message_t *message)
+{
+    _notmuch_message_ensure_property_map (message);
+
+    return message->property_map;
+}
+
+notmuch_bool_t
+_notmuch_message_frozen (notmuch_message_t *message)
+{
+    return message->frozen;
+}