image: Significantly refactor how backends are registered

3 files changed, 17 insertions, 34 deletions

diff --git a/image/backends/backends.hh b/image/backends/backends.hh
deleted file mode 100644
index 3199ee0..0000000
--- a/image/backends/backends.hh
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * backends.hh - Horizon Image Creation backend table
- * image, the image processing utilities for
- * Project Horizon
- *
- * Copyright (c) 2020 Adélie Linux and contributors.  All rights reserved.
- * This code is licensed under the AGPL 3.0 license, as noted in the
- * LICENSE-code file in the root directory of this repository.
- *
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-
-#pragma once
-
-#include <functional>
-#include <string>
-#include <vector>
-
-namespace Horizon {
-namespace Image {
-
-class BasicBackend;
-
-struct BackendDescriptor {
-    std::string type_code;
-    std::string description;
-    std::function<BasicBackend *(std::string, std::string)> creation_fn;
-};
-
-extern std::vector<BackendDescriptor> known_backends;
-
-}
-}
diff --git a/image/backends/basic.cc b/image/backends/basic.cc
index 908f1d9..dbe387c 100644
--- a/image/backends/basic.cc
+++ b/image/backends/basic.cc
@@ -11,7 +11,6 @@
  */
 
 #include "basic.hh"
-#include "backends.hh"
 
 namespace Horizon {
 namespace Image {
@@ -21,6 +20,10 @@ std::vector<BackendDescriptor> known_backends = {
    {"squashfs", "Create a SquashFS image (.squashfs)", [](std::string, std::string){ return nullptr; } }
 };
 
+const std::vector<BackendDescriptor> BasicBackend::available_backends() {
+    return known_backends;
+}
+
 int BasicBackend::prepare() {
     /* The default implementation returns success immediately;
      * no preparation is required. */
diff --git a/image/backends/basic.hh b/image/backends/basic.hh
index d39c57e..3181f69 100644
--- a/image/backends/basic.hh
+++ b/image/backends/basic.hh
@@ -12,11 +12,21 @@
 
 #pragma once
 
+#include <functional>
 #include <string>
+#include <vector>
 
 namespace Horizon {
 namespace Image {
 
+class BasicBackend;
+
+struct BackendDescriptor {
+    std::string type_code;
+    std::string description;
+    std::function<BasicBackend *(std::string, std::string)> creation_fn;
+};
+
 class BasicBackend {
 public:
     /*! Create the backend object.
@@ -43,6 +53,9 @@ public:
      */
     virtual int finalise();
 
+    /*! Returns a list of available backends. */
+    static const std::vector<BackendDescriptor> available_backends();
+
     /*! The intermediate directory which contains the sysroot the image
      *  should contain. */
     const std::string &ir_dir;