Support using app-extensions during the build

This adds add-build-extensions which is similar to add-extensions
except the extension is added at build-init time, so can be
used during the build. It can also optionally be removed after
the build is done.

This depends on the flatpak work in:
  https://github.com/flatpak/flatpak/pull/1598

With this I was able to build the following app which runs 32bit binaries
in a 64bit build:

```
{
    "app-id": "org.example.Multilib",
    "runtime": "org.freedesktop.Platform",
    "sdk": "org.freedesktop.Sdk",
    "runtime-version": "1.6",
    "command": "/usr/bin/true",
    "add-build-extensions": {
        "org.freedesktop.Platform.Compat32": {
            "directory": "lib/32bit",
            "add-ld-path": "lib",
            "version": "1.6"
        }
    },
    "modules": [
        {
            "name": "test 32bit",
            "buildsystem": "simple",
            "build-commands": [
                "ln -s /app/lib/32bit/lib/ld-linux.so.2 /app/lib/ld-linux.so.2",
                "/app/lib/32bit/bin/echo echoing from 32bit world"
            ]
        }
    ]
}
```

Closes: #129
Approved by: alexlarsson

doc/flatpak-manifest.xml

@@ -192,6 +192,10 @@
                     <term><option>add-extensions</option> (objects)</term>
                     <listitem><para>This is a dictionary of extension objects. The key is the name of the extension. See below for details.</para></listitem>
                 </varlistentry>
+                <varlistentry>
+                    <term><option>add-build-extensions</option> (objects)</term>
+                    <listitem><para>This is a dictionary of extension objects similar to add-extensions. The main difference is that the extensions are added early and are available for use during the build.</para></listitem>
+                </varlistentry>
                 <varlistentry>
                     <term><option>cleanup</option> (array of strings)</term>
                     <listitem><para>An array of file patterns that should be removed at the end.
@@ -377,7 +381,14 @@
                     <listitem><para>If this is true, then the data
                     created in the extension directory is omitted from
                     the result, and instead packaged in a separate
-                    extension..</para></listitem>
+                    extension.</para></listitem>
+                </varlistentry>
+                <varlistentry>
+                    <term><option>remove-after-build</option> (boolean)</term>
+                    <listitem><para>If this is true, the extension is
+                    removed during when finishing. This is only
+                    interesting for extensions in the
+                    add-build-extensions property.</para></listitem>
                 </varlistentry>
             </variablelist>
             <para>

src/builder-extension.c

@@ -53,6 +53,7 @@ struct BuilderExtension
   char           *subdirectory_suffix;
   char           *version;
   char           *versions;
+  gboolean        remove_after_build;
 };
 
 typedef struct
@@ -77,6 +78,7 @@ enum {
   PROP_SUBDIRECTORY_SUFFIX,
   PROP_VERSION,
   PROP_VERSIONS,
+  PROP_REMOVE_AFTER_BUILD,
   LAST_PROP
 };
 
@@ -116,6 +118,10 @@ builder_extension_get_property (GObject    *object,
       g_value_set_boolean (value, self->bundle);
       break;
 
+    case PROP_REMOVE_AFTER_BUILD:
+      g_value_set_boolean (value, self->remove_after_build);
+      break;
+
     case PROP_AUTODELETE:
       g_value_set_boolean (value, self->autodelete);
       break;
@@ -184,6 +190,10 @@ builder_extension_set_property (GObject      *object,
       self->bundle = g_value_get_boolean (value);
       break;
 
+    case PROP_REMOVE_AFTER_BUILD:
+      self->remove_after_build = g_value_get_boolean (value);
+      break;
+
     case PROP_AUTODELETE:
       self->autodelete = g_value_get_boolean (value);
       break;
@@ -263,6 +273,13 @@ builder_extension_class_init (BuilderExtensionClass *klass)
                                                          "",
                                                          FALSE,
                                                          G_PARAM_READWRITE));
+  g_object_class_install_property (object_class,
+                                   PROP_REMOVE_AFTER_BUILD,
+                                   g_param_spec_boolean ("remove-after-build",
+                                                         "",
+                                                         "",
+                                                         FALSE,
+                                                         G_PARAM_READWRITE));
   g_object_class_install_property (object_class,
                                    PROP_AUTODELETE,
                                    g_param_spec_boolean ("autodelete",
@@ -361,6 +378,11 @@ builder_extension_get_name (BuilderExtension *self)
   return self->name;
 }
 
+const char *
+builder_extension_get_version (BuilderExtension *self)
+{
+  return self->version;
+}
 
 gboolean
 builder_extension_is_bundled (BuilderExtension *self)
@@ -396,6 +418,15 @@ add_argb (BuilderExtension  *self,
     add_arg (self, args, key, "true");
 }
 
+void
+builder_extension_add_remove_args (BuilderExtension  *self,
+                                   GPtrArray *args)
+{
+  if (self->remove_after_build)
+    g_ptr_array_add (args,
+                     g_strdup_printf ("--remove-extension=%s", self->name));
+}
+
 void
 builder_extension_add_finish_args (BuilderExtension  *self,
                                    GPtrArray *args)
@@ -440,4 +471,5 @@ builder_extension_checksum (BuilderExtension  *self,
   builder_cache_checksum_str (cache, self->subdirectory_suffix);
   builder_cache_checksum_str (cache, self->version);
   builder_cache_checksum_str (cache, self->versions);
+  builder_cache_checksum_compat_boolean (cache, self->remove_after_build);
 }

src/builder-extension.h

@@ -42,11 +42,14 @@ GType builder_extension_get_type (void);
 void   builder_extension_set_name (BuilderExtension *self,
                                    const char *name);
 const char * builder_extension_get_name (BuilderExtension *self);
+const char * builder_extension_get_version (BuilderExtension *self);
 
 gboolean builder_extension_is_bundled (BuilderExtension *self);
 const char * builder_extension_get_directory (BuilderExtension *self);
 
-void    builder_extension_add_finish_args (BuilderExtension  *self,
+void     builder_extension_add_remove_args (BuilderExtension  *self,
+                                            GPtrArray *args);
+void     builder_extension_add_finish_args (BuilderExtension  *self,
                                            GPtrArray *args);
 void     builder_extension_checksum (BuilderExtension  *self,
                                      BuilderCache   *cache,

src/builder-manifest.c

@@ -104,6 +104,7 @@ struct BuilderManifest
   GList          *modules;
   GList          *expanded_modules;
   GList          *add_extensions;
+  GList          *add_build_extensions;
 };
 
 typedef struct
@@ -162,6 +163,7 @@ enum {
   PROP_DESKTOP_FILE_NAME_SUFFIX,
   PROP_COLLECTION_ID,
   PROP_ADD_EXTENSIONS,
+  PROP_ADD_BUILD_EXTENSIONS,
   PROP_EXTENSION_TAG,
   LAST_PROP
 };
@@ -190,6 +192,7 @@ builder_manifest_finalize (GObject *object)
   g_clear_object (&self->build_options);
   g_list_free_full (self->modules, g_object_unref);
   g_list_free_full (self->add_extensions, g_object_unref);
+  g_list_free_full (self->add_build_extensions, g_object_unref);
   g_list_free (self->expanded_modules);
   g_strfreev (self->cleanup);
   g_strfreev (self->cleanup_commands);
@@ -345,6 +348,10 @@ builder_manifest_get_property (GObject    *object,
       g_value_set_pointer (value, self->add_extensions);
       break;
 
+    case PROP_ADD_BUILD_EXTENSIONS:
+      g_value_set_pointer (value, self->add_build_extensions);
+      break;
+
     case PROP_CLEANUP:
       g_value_set_boxed (value, self->cleanup);
       break;
@@ -563,6 +570,12 @@ builder_manifest_set_property (GObject      *object,
       self->add_extensions = g_value_get_pointer (value);
       break;
 
+    case PROP_ADD_BUILD_EXTENSIONS:
+      g_list_free_full (self->add_build_extensions, g_object_unref);
+      /* NOTE: This takes ownership of the list! */
+      self->add_build_extensions = g_value_get_pointer (value);
+      break;
+
     case PROP_CLEANUP:
       tmp = self->cleanup;
       self->cleanup = g_strdupv (g_value_get_boxed (value));
@@ -845,6 +858,12 @@ builder_manifest_class_init (BuilderManifestClass *klass)
                                                          "",
                                                          "",
                                                          G_PARAM_READWRITE));
+  g_object_class_install_property (object_class,
+                                   PROP_ADD_BUILD_EXTENSIONS,
+                                   g_param_spec_pointer ("add-build-extensions",
+                                                         "",
+                                                         "",
+                                                         G_PARAM_READWRITE));
   g_object_class_install_property (object_class,
                                    PROP_CLEANUP,
                                    g_param_spec_boxed ("cleanup",
@@ -1060,19 +1079,26 @@ builder_manifest_serialize_property (JsonSerializable *serializable,
 
       return retval;
     }
-  else if (strcmp (property_name, "add-extensions") == 0)
+  else if (strcmp (property_name, "add-extensions") == 0 ||
+           strcmp (property_name, "add-build-extensions") == 0)
     {
       BuilderManifest *self = BUILDER_MANIFEST (serializable);
       JsonNode *retval = NULL;
+      GList *extensions;
 
-      if (self->add_extensions)
+      if (strcmp (property_name, "add-extensions") == 0)
+        extensions = self->add_extensions;
+      else
+        extensions = self->add_build_extensions;
+
+      if (extensions)
         {
           JsonObject *object;
           GList *l;
 
           object = json_object_new ();
 
-          for (l = self->add_extensions; l != NULL; l = l->next)
+          for (l = extensions; l != NULL; l = l->next)
             {
               BuilderExtension *e = l->data;
               JsonNode *child = json_gobject_serialize (G_OBJECT (e));
@@ -1181,7 +1207,8 @@ builder_manifest_deserialize_property (JsonSerializable *serializable,
 
       return FALSE;
     }
-  else if (strcmp (property_name, "add-extensions") == 0)
+  else if (strcmp (property_name, "add-extensions") == 0 ||
+           strcmp (property_name, "add-build-extensions") == 0)
     {
       if (JSON_NODE_TYPE (property_node) == JSON_NODE_NULL)
         {
@@ -1305,6 +1332,12 @@ builder_manifest_get_add_extensions (BuilderManifest *self)
   return self->add_extensions;
 }
 
+GList *
+builder_manifest_get_add_build_extensions (BuilderManifest *self)
+{
+  return self->add_build_extensions;
+}
+
 static const char *
 builder_manifest_get_runtime_version (BuilderManifest *self)
 {
@@ -1493,6 +1526,7 @@ builder_manifest_init_app_dir (BuilderManifest *self,
   g_autoptr(GSubprocess) subp = NULL;
   g_autoptr(GPtrArray) args = NULL;
   g_autofree char *commandline = NULL;
+  GList *l;
   int i;
 
   g_print ("Initializing build dir\n");
@@ -1530,6 +1564,9 @@ builder_manifest_init_app_dir (BuilderManifest *self,
         g_ptr_array_add (args, g_strdup ("--writable-sdk"));
     }
 
+  for (l = self->add_build_extensions; l != NULL; l = l->next)
+    builder_extension_add_finish_args (l->data, args);
+
   for (i = 0; self->sdk_extensions != NULL && self->sdk_extensions[i] != NULL; i++)
     {
       const char *ext = self->sdk_extensions[i];
@@ -1607,6 +1644,8 @@ builder_manifest_checksum (BuilderManifest *self,
                            BuilderCache    *cache,
                            BuilderContext  *context)
 {
+  GList *l;
+
   builder_cache_checksum_str (cache, BUILDER_MANIFEST_CHECKSUM_VERSION);
   builder_cache_checksum_str (cache, self->id);
   /* No need to include version here, it doesn't affect the build */
@@ -1633,6 +1672,12 @@ builder_manifest_checksum (BuilderManifest *self,
 
   if (self->build_options)
     builder_options_checksum (self->build_options, cache, context);
+
+  for (l = self->add_build_extensions; l != NULL; l = l->next)
+    {
+      BuilderExtension *e = l->data;
+      builder_extension_checksum (e, cache, context);
+    }
 }
 
 static void
@@ -2723,6 +2768,9 @@ builder_manifest_finish (BuilderManifest *self,
             g_ptr_array_add (args, g_strdup (self->finish_args[i]));
         }
 
+      for (l = self->add_build_extensions; l != NULL; l = l->next)
+        builder_extension_add_remove_args (l->data, args);
+
       for (l = self->add_extensions; l != NULL; l = l->next)
         builder_extension_add_finish_args (l->data, args);
 
@@ -3607,6 +3655,23 @@ builder_manifest_install_deps (BuilderManifest *self,
                                                 error))
     return FALSE;
 
+  for (GList *l = self->add_build_extensions; l != NULL; l = l->next)
+    {
+      BuilderExtension *extension = l->data;
+      const char *name = builder_extension_get_name (extension);
+      const char *version = builder_extension_get_version (extension);
+
+      if (name == NULL || version == NULL)
+        continue;
+
+      g_print ("Dependency Extension: %s %s\n", name, version);
+      if (!builder_manifest_install_dep (self, context, remote, opt_user, opt_installation,
+                                         name, version,
+                                         opt_yes,
+                                         error))
+        return FALSE;
+    }
+
   return TRUE;
 }
 

src/builder-manifest.h

@@ -58,6 +58,7 @@ char *          builder_manifest_get_locale_id_platform (BuilderManifest *self);
 BuilderOptions *builder_manifest_get_build_options (BuilderManifest *self);
 GList *         builder_manifest_get_modules (BuilderManifest *self);
 GList *         builder_manifest_get_add_extensions (BuilderManifest *self);
+GList *         builder_manifest_get_add_build_extensions (BuilderManifest *self);
 const char *    builder_manifest_get_branch (BuilderManifest *self);
 void            builder_manifest_set_default_branch (BuilderManifest *self,
                                                      const char *default_branch);