[chore] move caches to a separate State{} structure (#1078)

* move caches to a separate State{} structure

Signed-off-by: kim <grufwub@gmail.com>

* fix call to log.Panic not using formatted call

Signed-off-by: kim <grufwub@gmail.com>

* move caches to use interfaces, to make switchouts easier in future

Signed-off-by: kim <grufwub@gmail.com>

* fix rebase issue

Signed-off-by: kim <grufwub@gmail.com>

* improve code comment

Signed-off-by: kim <grufwub@gmail.com>

* fix further issues after rebase

Signed-off-by: kim <grufwub@gmail.com>

* heh

Signed-off-by: kim <grufwub@gmail.com>

* add missing license text

Signed-off-by: kim <grufwub@gmail.com>

Signed-off-by: kim <grufwub@gmail.com>

1 files changed, 49 insertions, 0 deletions

diff --git a/internal/state/state.go b/internal/state/state.go
new file mode 100644
index 000000000..fb6d6f41a
--- /dev/null
+++ b/internal/state/state.go
@@ -0,0 +1,49 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package state
+
+import (
+	"github.com/superseriousbusiness/gotosocial/internal/cache"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+)
+
+// State provides a means of dependency injection and sharing of resources
+// across different subpackages of the GoToSocial codebase. DO NOT assume
+// that any particular field will be initialized if you are accessing this
+// during initialization. A pointer to a State{} is often passed during
+// subpackage initialization, while the returned subpackage type will later
+// then be set and stored within the State{} itself.
+type State struct {
+	// Caches provides access to this state's collection of caches.
+	Caches cache.Caches
+
+	// DB provides access to the database.
+	DB db.DB
+
+	// prevent pass-by-value.
+	_ nocopy
+}
+
+// nocopy when embedded will signal linter to
+// error on pass-by-value of parent struct.
+type nocopy struct{}
+
+func (*nocopy) Lock() {}
+
+func (*nocopy) Unlock() {}