mu: add '--lazy-check' option for indexing

Add an option --lazy-check to ignore any directories that don't have
their ctime changed since the last indexing operation.

There are a few corner-cases (such as editing a message outside mu's
control) where this might miss a change, but apart from that, makes
indexing in for a maildir (and its sub-maildirs) almost a no-op if there
were no changes.

lib/mu-index.c

@@ -95,6 +95,7 @@ struct _MuIndexCallbackData {
 	void*				_user_data;
 	MuIndexStats*			_stats;
 	gboolean			_reindex;
+	gboolean			_lazy_check;
 	time_t				_dirstamp;
 	guint				_max_filesize;
 };
@@ -216,30 +217,51 @@ on_run_maildir_msg (const char *fullpath, const char *mdir,
 	return result;
 }
 
+static time_t
+get_dir_timestamp (const char *path)
+{
+	struct stat statbuf;
+
+	if (stat (path, &statbuf) != 0) {
+		g_warning ("failed to stat %s: %s",
+			   path, strerror(errno));
+		return 0;
+	}
+
+	return statbuf.st_ctime;
+}
 
 static MuError
 on_run_maildir_dir (const char* fullpath, gboolean enter,
 		    MuIndexCallbackData *data)
 {
 	GError *err;
+
 	err = NULL;
 
-	/* xapian stores a per-dir timestamp; we use this timestamp
+	/* xapian stores a per-dir timestamp; we use this timestamp to determine
-	 *  to determine whether a message is up-to-data
+	 * whether a message is up-to-date
 	 */
 	if (enter) {
 		data->_dirstamp =
 			mu_store_get_timestamp (data->_store, fullpath, &err);
-		g_debug ("entering %s (ts==%u)",
+		/* in 'lazy' mode, we only check the dir timestamp, and if it's
-			 fullpath, (unsigned)data->_dirstamp);
+		 * up to date, we don't bother with this dir. This fails to
+		 * account for messages below this dir that have merely
+		 * _changed_ though */
+		if (data->_lazy_check && mu_maildir_is_leaf_dir(fullpath)) {
+			time_t dirstamp;
+			dirstamp = get_dir_timestamp (fullpath);
+			if (dirstamp <= data->_dirstamp) {
+				g_debug ("ignore %s (up-to-date)", fullpath);
+				return MU_IGNORE;
+			}
+		}
+		g_debug ("entering %s", fullpath);
 	} else {
-		time_t now;
-		now = time (NULL);
-
 		mu_store_set_timestamp (data->_store, fullpath,
-					now, &err);
+					time(NULL), &err);
-		g_debug ("leaving %s (ts=%u)",
+		g_debug ("leaving %s", fullpath);
-			 fullpath, (unsigned)data->_dirstamp);
 	}
 
 	if (data->_idx_dir_cb)
@@ -276,7 +298,8 @@ check_path (const char *path)
 
 static void
 init_cb_data (MuIndexCallbackData *cb_data, MuStore  *xapian,
-	      gboolean reindex, guint max_filesize, MuIndexStats *stats,
+	      gboolean reindex, gboolean lazycheck,
+	      guint max_filesize, MuIndexStats *stats,
 	      MuIndexMsgCallback msg_cb, MuIndexDirCallback dir_cb,
 	      void *user_data)
 {
@@ -287,6 +310,7 @@ init_cb_data (MuIndexCallbackData *cb_data, MuStore  *xapian,
 	cb_data->_store         = xapian;
 
 	cb_data->_reindex      = reindex;
+	cb_data->_lazy_check   = lazycheck;
 	cb_data->_dirstamp     = 0;
 	cb_data->_max_filesize = max_filesize;
 
@@ -318,7 +342,8 @@ mu_index_set_xbatch_size (MuIndex *index, guint xbatchsize)
 
 MuError
 mu_index_run (MuIndex *index, const char *path,
-	      gboolean reindex, MuIndexStats *stats,
+	      gboolean reindex, gboolean lazycheck,
+	      MuIndexStats *stats,
 	      MuIndexMsgCallback msg_cb, MuIndexDirCallback dir_cb,
 	      void *user_data)
 {
@@ -336,7 +361,7 @@ mu_index_run (MuIndex *index, const char *path,
 		return MU_ERROR;
 	}
 
-	init_cb_data (&cb_data, index->_store, reindex,
+	init_cb_data (&cb_data, index->_store, reindex, lazycheck,
 		      index->_max_filesize, stats,
 		      msg_cb, dir_cb, user_data);
 

lib/mu-index.h

@@ -119,6 +119,8 @@ typedef MuError (*MuIndexDirCallback) (const char* path, gboolean enter,
  * @param path the path to index. This must be an absolute path
  * @param force if != 0, force re-indexing already index messages; this is
  *         obviously a lot slower than only indexing new/changed messages
+ * @param lazycheck whether ignore subdirectoryies that have up-to-date
+ * timestamps.
  * @param stats a structure with some statistics about the results;
  * note that this function does *not* reset the struct values to allow
  * for cumulative stats from multiple calls. If needed, you can use
@@ -132,12 +134,13 @@ typedef MuError (*MuIndexDirCallback) (const char* path, gboolean enter,
  * case of some error.
  */
 MuError mu_index_run (MuIndex *index, const char *path, gboolean force,
-		      MuIndexStats *stats, MuIndexMsgCallback msg_cb,
+		      gboolean lazycheck, MuIndexStats *stats,
+		      MuIndexMsgCallback msg_cb,
 		      MuIndexDirCallback dir_cb, void *user_data);
 
 /**
- * gather some statistics about the Maildir; this is usually much faster
+ * gather some statistics about the Maildir; this is usually much faster than
- * than mu_index_run, and can thus be used to provide some information to the user
+ * mu_index_run, and can thus be used to provide some information to the user
  * note though that the statistics may be different from the reality that
  * mu_index_run sees, when there are updates in the Maildir
  *

lib/mu-maildir.c

@@ -248,21 +248,20 @@ process_file (const char* fullpath, const gchar* mdir,
  * determine if path is a maildir leaf-dir; ie. if it's 'cur' or 'new'
  * (we're skipping 'tmp' for obvious reasons)
  */
-G_GNUC_CONST static gboolean
+gboolean
-is_maildir_new_or_cur (const char *path)
+mu_maildir_is_leaf_dir (const char *path)
 {
 	size_t len;
 
-	g_return_val_if_fail (path, FALSE);
-
 	/* path is the full path; it cannot possibly be shorter
 	 * than 4 for a maildir (/cur or /new) */
-	len = strlen (path);
+	len = path ? strlen (path) : 0;
 	if (G_UNLIKELY(len < 4))
 		return FALSE;
 
-	/* optimization; one further idea would be cast the 4 bytes to an integer
+	/* optimization; one further idea would be cast the 4 bytes to an
-	 * and compare that -- need to think about alignment, endianness */
+	 * integer and compare that -- need to think about alignment,
+	 * endianness */
 
 	if (path[len - 4] == G_DIR_SEPARATOR &&
 	    path[len - 3] == 'c' &&
@@ -415,7 +414,7 @@ process_dir_entry (const char* path, const char* mdir, struct dirent *entry,
 
 	switch (d_type) {
 	case DT_REG: /* we only want files in cur/ and new/ */
-		if (!is_maildir_new_or_cur (path))
+		if (!mu_maildir_is_leaf_dir (path))
 			return MU_OK;
 
 		return process_file (fullpath, mdir, cb_msg, data);
@@ -531,27 +530,30 @@ process_dir (const char* path, const char* mdir,
 		return MU_OK;
 	}
 
+	if (dir_cb) {
+		MuError rv;
+		rv = dir_cb (path, TRUE/*enter*/, data);
+		/* ignore this dir; not necessarily an _error_, dir might
+		 * be up-to-date and return MU_IGNORE */
+		if (rv == MU_IGNORE)
+			return MU_OK;
+		else if (rv != MU_OK)
+			return rv;
+	}
+
 	dir = opendir (path);
 	if (!dir) {
 		g_warning ("cannot access %s: %s", path, strerror(errno));
 		return MU_OK;
 	}
 
-	if (dir_cb) {
+	result = process_dir_entries (dir, path, mdir, msg_cb, dir_cb,
-		MuError rv;
+				      full, data);
-		rv = dir_cb (path, TRUE, data);
-		if (rv != MU_OK) {
-			closedir (dir);
-			return rv;
-		}
-	}
-
-	result = process_dir_entries (dir, path, mdir, msg_cb, dir_cb, full, data);
 	closedir (dir);
 
 	/* only run dir_cb if it exists and so far, things went ok */
 	if (dir_cb && result == MU_OK)
-		return dir_cb (path, FALSE, data);
+		return dir_cb (path, FALSE/*leave*/, data);
 
 	return result;
 }
@@ -798,15 +800,16 @@ mu_maildir_get_new_path (const char *oldpath, const char *new_mdir,
 	if (new_name)
 		mfile = get_new_basename ();
 	else {
-		/* determine the name of the mailfile, stripped of its flags, as well
+		/* determine the name of the mailfile, stripped of its flags, as
-		 * as any custom (non-standard) flags */
+		 * well as any custom (non-standard) flags */
 		char *cur;
 		mfile = g_path_get_basename (oldpath);
 		for (cur = &mfile[strlen(mfile)-1]; cur > mfile; --cur) {
 			if ((*cur == ':' || *cur == '!') &&
 			    (cur[1] == '2' && cur[2] == ',')) {
 				/* get the custom flags (if any) */
-				custom_flags = mu_flags_custom_from_str (cur + 3);
+				custom_flags =
+					mu_flags_custom_from_str (cur + 3);
 				cur[0] = '\0'; /* strip the flags */
 				break;
 			}
@@ -839,8 +842,6 @@ get_file_size (const char* path)
 }
 
 
-
-
 static gboolean
 msg_move_check_pre (const gchar *src, const gchar *dst, GError **err)
 {

lib/mu-maildir.h

@@ -129,6 +129,15 @@ MuError mu_maildir_walk (const char *path, MuMaildirWalkMsgCallback cb_msg,
 gboolean mu_maildir_clear_links (const gchar* dir, GError **err);
 
 
+
+/**
+ * whether the directory path ends in '/cur/' or '/new/'
+ *
+ * @param path some path
+ */
+gboolean mu_maildir_is_leaf_dir (const char *path);
+
+
 /**
  * get the Maildir flags from the full path of a mailfile. The flags
  * are as specified in http://cr.yp.to/proto/maildir.html, plus

mu/mu-cmd-index.c

@@ -1,7 +1,7 @@
 /* -*-mode: c; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-*/
 
 /*
-** Copyright (C) 2008-2013 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
+** Copyright (C) 2008-2016 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
 **
 ** 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
@@ -319,7 +319,8 @@ cmd_index (MuIndex *midx, MuConfig *opts, MuIndexStats *stats, GError **err)
 
 	newline_before_on();
 
-	rv = mu_index_run (midx, opts->maildir, opts->rebuild, stats,
+	rv = mu_index_run (midx, opts->maildir, opts->rebuild,
+			   opts->lazycheck, stats,
 			   show_progress ?
 			   (MuIndexMsgCallback)index_msg_cb :
 			   (MuIndexMsgCallback)index_msg_silent_cb,

mu/mu-config.c

@@ -148,6 +148,8 @@ config_options_group_index (void)
 		 "top of the maildir", "<maildir>"},
 		{"rebuild", 0, 0, G_OPTION_ARG_NONE, &MU_CONFIG.rebuild,
 		 "rebuild the database from scratch (false)", NULL},
+		{"lazy-check", 0, 0, G_OPTION_ARG_NONE, &MU_CONFIG.lazycheck,
+		 "only check dir-timestamps (false)", NULL},
 		{"my-address", 0, 0, G_OPTION_ARG_STRING_ARRAY,
 		 &MU_CONFIG.my_addresses,
 		 "my e-mail address (regexp); can be used multiple times",

mu/mu-config.h

@@ -112,6 +112,8 @@ struct _MuConfig {
 	gboolean        rebuild;	/* empty the database before indexing */
 	gboolean        autoupgrade;    /* automatically upgrade db
 					 * when needed */
+	gboolean        lazycheck;      /* don't check dirs with up-to-date
+					 * timestamps */
 	int             xbatchsize;     /* batchsize for xapian
 					 * commits, or 0 for
 					 * default */