Add plugin tasks (#651)

pkg/plugin/task.go

@@ -0,0 +1,56 @@
+package plugin
+
+import (
+	"github.com/stashapp/stash/pkg/models"
+	"github.com/stashapp/stash/pkg/plugin/common"
+)
+
+// Task is the interface that handles management of a single plugin task.
+type Task interface {
+	// Start starts the plugin task. Returns an error if task could not be
+	// started or the task has already been started.
+	Start() error
+
+	// Stop instructs a running plugin task to stop and returns immediately.
+	// Use Wait to subsequently wait for the task to stop.
+	Stop() error
+
+	// Wait blocks until the plugin task is complete. Returns immediately if
+	// task has not been started.
+	Wait()
+
+	// GetResult returns the output of the plugin task. Returns nil if the task
+	// has not completed.
+	GetResult() *common.PluginOutput
+}
+
+type taskBuilder interface {
+	build(task pluginTask) Task
+}
+
+type pluginTask struct {
+	plugin           *Config
+	operation        *OperationConfig
+	serverConnection common.StashServerConnection
+	args             []*models.PluginArgInput
+
+	progress chan float64
+	result   *common.PluginOutput
+}
+
+func (t *pluginTask) GetResult() *common.PluginOutput {
+	return t.result
+}
+
+func (t *pluginTask) createTask() Task {
+	return t.plugin.Interface.getTaskBuilder().build(*t)
+}
+
+func (t *pluginTask) buildPluginInput() common.PluginInput {
+	args := applyDefaultArgs(t.args, t.operation.DefaultArgs)
+	t.serverConnection.PluginDir = t.plugin.getConfigPath()
+	return common.PluginInput{
+		ServerConnection: t.serverConnection,
+		Args:             toPluginArgs(args),
+	}
+}