[evolution-data-server] EBookMetaBackend: Add 'backend_module_directory' property into the class

[Milan Crha <mcrha src gnome org>]

commit 542a3b2fff7b01da0efdde5c74f749ce8cb35a91
Author: Milan Crha <mcrha redhat com>
Date:   Wed Feb 24 17:37:14 2021 +0100

    EBookMetaBackend: Add 'backend_module_directory' property into the class
    
    With it the descendants can define where the backend file is located,
    in case it's built in a custom prefix.

 src/addressbook/libedata-book/e-book-meta-backend.c | 2 ++
 src/addressbook/libedata-book/e-book-meta-backend.h | 6 +++++-
 2 files changed, 7 insertions(+), 1 deletion(-)
---
diff --git a/src/addressbook/libedata-book/e-book-meta-backend.c 
b/src/addressbook/libedata-book/e-book-meta-backend.c
index b4dd9eb98..4a76e5b9f 100644
--- a/src/addressbook/libedata-book/e-book-meta-backend.c
+++ b/src/addressbook/libedata-book/e-book-meta-backend.c
@@ -1866,6 +1866,8 @@ ebmb_get_direct_book (EBookBackend *book_backend)
        /* Support in-tree testing / relocated modules */
        if (modules_env) {
                backend_path = g_build_filename (modules_env, klass->backend_module_filename, NULL);
+       } else if (klass->backend_module_directory) {
+               backend_path = g_build_filename (klass->backend_module_directory, 
klass->backend_module_filename, NULL);
        } else {
                backend_path = g_build_filename (BACKENDDIR, klass->backend_module_filename, NULL);
        }
diff --git a/src/addressbook/libedata-book/e-book-meta-backend.h 
b/src/addressbook/libedata-book/e-book-meta-backend.h
index 23f80eb1a..15592e7a5 100644
--- a/src/addressbook/libedata-book/e-book-meta-backend.h
+++ b/src/addressbook/libedata-book/e-book-meta-backend.h
@@ -174,8 +174,12 @@ struct _EBookMetaBackendClass {
                                                 gchar **out_certificate_pem,
                                                 GTlsCertificateFlags *out_certificate_errors);
 
+       /* For Direct Read Access - directory with the backend_module_filename,
+          when it differs from the default module directory */
+       const gchar *backend_module_directory;
+
        /* Padding for future expansion */
-       gpointer reserved[9];
+       gpointer reserved[8];
 };
 
 GType          e_book_meta_backend_get_type    (void) G_GNUC_CONST;