lib: cache configuration information from database

The main goal is to allow configuration information to be temporarily
overridden by a separate config file. That will require further
changes not in this commit.

The performance impact is unclear, and will depend on the balance
between number of queries and number of distinct metadata items read
on the first call to n_d_get_config.

diff --git a/lib/config.cc b/lib/config.cc
index 0b760dbcc2063deeefde553fa66b5421fcf23d02..c079d752eef07e5ad8c9588756f95ecc050bc794 100644 (file)
--- a/lib/config.cc
+++ b/lib/config.cc
@@ -50,6 +50,11 @@ notmuch_database_set_config (notmuch_database_t *notmuch,
     if (status)
        return status;
 
+    if (! notmuch->config) {
+       if ((status = _notmuch_config_load_from_database (notmuch)))
+           return status;
+    }
+
     try {
        notmuch->writable_xapian_db->set_metadata (CONFIG_PREFIX + key, value);
     } catch (const Xapian::Error &error) {
@@ -58,7 +63,13 @@ notmuch_database_set_config (notmuch_database_t *notmuch,
        _notmuch_database_log (notmuch, "Error: A Xapian exception occurred setting metadata: %s\n",
                               error.get_msg ().c_str ());
     }
-    return status;
+
+    if (status)
+       return status;
+
+    _notmuch_string_map_set (notmuch->config, key, value);
+
+    return NOTMUCH_STATUS_SUCCESS;
 }
 
 static notmuch_status_t
@@ -84,17 +95,25 @@ notmuch_database_get_config (notmuch_database_t *notmuch,
                             const char *key,
                             char **value)
 {
-    std::string strval;
+    const char* stored_val;
     notmuch_status_t status;
 
+    if (! notmuch->config) {
+       if ((status = _notmuch_config_load_from_database (notmuch)))
+           return status;
+    }
+
     if (! value)
        return NOTMUCH_STATUS_NULL_POINTER;
 
-    status = _metadata_value (notmuch, key, strval);
-    if (status)
-       return status;
-
-    *value = strdup (strval.c_str ());
+    stored_val = _notmuch_string_map_get (notmuch->config, key);
+    if (! stored_val) {
+       /* XXX in principle this API should be fixed so empty string
+        * is distinguished from not found */
+       *value = strdup("");
+    } else {
+       *value = strdup (stored_val);
+    }
 
     return NOTMUCH_STATUS_SUCCESS;
 }
@@ -201,3 +220,28 @@ notmuch_config_list_destroy (notmuch_config_list_t *list)
 {
     talloc_free (list);
 }
+
+notmuch_status_t
+_notmuch_config_load_from_database (notmuch_database_t *notmuch)
+{
+    notmuch_status_t status = NOTMUCH_STATUS_SUCCESS;
+    notmuch_config_list_t *list;
+
+    if (notmuch->config == NULL)
+       notmuch->config = _notmuch_string_map_create (notmuch);
+
+    if (unlikely(notmuch->config == NULL))
+       return NOTMUCH_STATUS_OUT_OF_MEMORY;
+
+    status = notmuch_database_get_config_list (notmuch, "", &list);
+    if (status)
+       return status;
+
+    for (; notmuch_config_list_valid (list); notmuch_config_list_move_to_next (list)) {
+       _notmuch_string_map_append (notmuch->config,
+                                   notmuch_config_list_key (list),
+                                   notmuch_config_list_value (list));
+    }
+
+    return status;
+}

diff --git a/lib/database-private.h b/lib/database-private.h
index c9bc712b46c1a0b51c8d93af9189111604b7dd7f..d83cf0d0ae0bc674cd341703d004082d6504dcce 100644 (file)
--- a/lib/database-private.h
+++ b/lib/database-private.h
@@ -228,6 +228,9 @@ struct _notmuch_database {
      * here, but at least they are small */
     notmuch_string_map_t *user_prefix;
     notmuch_string_map_t *user_header;
+
+    /* Cached and possibly overridden configuration */
+    notmuch_string_map_t *config;
 };
 
 /* Prior to database version 3, features were implied by the database

diff --git a/lib/notmuch-private.h b/lib/notmuch-private.h
index 51016b0b430017397cc5cc86ab518994fe432550..969caac0eb15c2d73ef057d9854fdc9b10ae9399 100644 (file)
--- a/lib/notmuch-private.h
+++ b/lib/notmuch-private.h
@@ -704,6 +704,9 @@ struct _notmuch_indexopts {
 
 #define EMPTY_STRING(s) ((s)[0] == '\0')
 
+/* config.cc */
+notmuch_status_t
+_notmuch_config_load_from_database (notmuch_database_t * db);
 NOTMUCH_END_DECLS
 
 #ifdef __cplusplus

diff --git a/lib/open.cc b/lib/open.cc
index 1b17e63a324062a76dc49cfd78e2a4cccd303b5c..0001794a60f5816d2131c3a074c13b58ae5f23ea 100644 (file)
--- a/lib/open.cc
+++ b/lib/open.cc
@@ -90,7 +90,7 @@ notmuch_database_open_verbose (const char *path,
     notmuch->exception_reported = false;
     notmuch->status_string = NULL;
     notmuch->path = talloc_strdup (notmuch, path);
-
+    notmuch->config = NULL;
     strip_trailing (notmuch->path, '/');
 
     notmuch->writable_xapian_db = NULL;
@@ -180,6 +180,11 @@ notmuch_database_open_verbose (const char *path,
        notmuch->query_parser->add_rangeprocessor (notmuch->date_range_processor);
        notmuch->query_parser->add_rangeprocessor (notmuch->last_mod_range_processor);
 
+       /* Configuration information is needed to set up query parser */
+       status = _notmuch_config_load_from_database (notmuch);
+       if (status)
+           goto DONE;
+
        status = _notmuch_database_setup_standard_query_fields (notmuch);
        if (status)
            goto DONE;

diff --git a/lib/prefix.cc b/lib/prefix.cc
index dd7b193d6ff090639a3eebf1d8a20f8396152f31..71a7699189d147b3c43ee5c74c9f73b9da15560d 100644 (file)
--- a/lib/prefix.cc
+++ b/lib/prefix.cc
@@ -166,8 +166,7 @@ _notmuch_database_setup_standard_query_fields (notmuch_database_t *notmuch)
 notmuch_status_t
 _notmuch_database_setup_user_query_fields (notmuch_database_t *notmuch)
 {
-    notmuch_config_list_t *list;
-    notmuch_status_t status;
+    notmuch_string_map_iterator_t *list;
 
     notmuch->user_prefix = _notmuch_string_map_create (notmuch);
     if (notmuch->user_prefix == NULL)
@@ -177,15 +176,16 @@ _notmuch_database_setup_user_query_fields (notmuch_database_t *notmuch)
     if (notmuch->user_header == NULL)
        return NOTMUCH_STATUS_OUT_OF_MEMORY;
 
-    status = notmuch_database_get_config_list (notmuch, CONFIG_HEADER_PREFIX, &list);
-    if (status)
-       return status;
+    list = _notmuch_string_map_iterator_create (notmuch->config, CONFIG_HEADER_PREFIX, FALSE);
+    if (! list)
+       INTERNAL_ERROR ("unable to read headers from configuration");
 
-    for (; notmuch_config_list_valid (list); notmuch_config_list_move_to_next (list)) {
+    for (; _notmuch_string_map_iterator_valid (list);
+        _notmuch_string_map_iterator_move_to_next (list)) {
 
        prefix_t query_field;
 
-       const char *key = notmuch_config_list_key (list)
+       const char *key = _notmuch_string_map_iterator_key (list)
                          + sizeof (CONFIG_HEADER_PREFIX) - 1;
 
        _notmuch_string_map_append (notmuch->user_prefix,
@@ -194,7 +194,7 @@ _notmuch_database_setup_user_query_fields (notmuch_database_t *notmuch)
 
        _notmuch_string_map_append (notmuch->user_header,
                                    key,
-                                   notmuch_config_list_value (list));
+                                   _notmuch_string_map_iterator_value (list));
 
        query_field.name = talloc_strdup (notmuch, key);
        query_field.prefix = _user_prefix (notmuch, key);
@@ -204,7 +204,7 @@ _notmuch_database_setup_user_query_fields (notmuch_database_t *notmuch)
        _setup_query_field_default (&query_field, notmuch);
     }
 
-    notmuch_config_list_destroy (list);
+    _notmuch_string_map_iterator_destroy (list);
 
     return NOTMUCH_STATUS_SUCCESS;
 }

diff --git a/test/T562-lib-database.sh b/test/T562-lib-database.sh
index dd4f2566a9922bf758209623064cf5d98dc0bec2..887851dd4b41af72894b002e4b0561ca6b562c1b 100755 (executable)
--- a/test/T562-lib-database.sh
+++ b/test/T562-lib-database.sh
@@ -340,7 +340,7 @@ test_expect_equal_file EXPECTED OUTPUT
 test_begin_subtest "get config from closed database"
 cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
     {
-        const char *result;
+        char *result;
         EXPECT0(notmuch_database_close (db));
         stat = notmuch_database_get_config (db, "foo", &result);
         printf("%d\n",  stat == NOTMUCH_STATUS_XAPIAN_EXCEPTION);
@@ -348,9 +348,8 @@ cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
 EOF
 cat <<EOF > EXPECTED
 == stdout ==
-1
+0
 == stderr ==
-Error: A Xapian exception occurred getting metadata: Database has been closed
 EOF
 test_expect_equal_file EXPECTED OUTPUT
 
@@ -376,7 +375,7 @@ cat c_head - c_tail <<'EOF' | test_C ${MAIL_DIR}
         notmuch_indexopts_t *result;
         EXPECT0(notmuch_database_close (db));
         result = notmuch_database_get_default_indexopts (db);
-        printf("%d\n",  result == NULL);
+        printf("%d\n", result != NULL);
     }
 EOF
 cat <<EOF > EXPECTED