worker/lib: implement an fswatcher interface

Implement an FSWatcher interface. The interface is used to abstract away
file system watchers, which have implementation specific backends. The
initial interface has one implementation: inotify for linux. Subsequent
commits will add a macOS watcher.

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Tested-by: Ben Lee-Cohen <ben@lee-cohen.com>
Acked-by: Robin Jarry <robin@jarry.cc>

1 files changed, 16 insertions, 0 deletions

diff --git a/worker/handlers/register.go b/worker/handlers/register.go
index c871f07b..c94a256e 100644
--- a/worker/handlers/register.go
+++ b/worker/handlers/register.go
@@ -2,6 +2,7 @@ package handlers
 
 import (
 	"fmt"
+	"runtime"
 
 	"git.sr.ht/~rjarry/aerc/worker/types"
 )
@@ -25,3 +26,18 @@ func GetHandlerForScheme(scheme string, worker *types.Worker) (types.Backend, er
 	}
 	return backend, nil
 }
+
+type WatcherFactoryFunc func() (types.FSWatcher, error)
+
+var watcherFactories map[string]WatcherFactoryFunc = make(map[string]WatcherFactoryFunc)
+
+func RegisterWatcherFactory(os string, fn WatcherFactoryFunc) {
+	watcherFactories[os] = fn
+}
+
+func NewWatcher() (types.FSWatcher, error) {
+	if fn, ok := watcherFactories[runtime.GOOS]; ok {
+		return fn()
+	}
+	return nil, fmt.Errorf("Unsupported OS: %s", runtime.GOOS)
+}