From 115fb9322ce4065bb7212e8979464d0f9c1db12d Mon Sep 17 00:00:00 2001
From: Tim Culverhouse <tim@timculverhouse.com>
Date: Tue, 20 Jun 2023 11:07:07 -0500
Subject: worker: add context to cancellable requests

Add a Context field to requests which we may want to cancel when
changing directories.

Add a Cancelled meta-message to inform the UI that a request was
cancelled (as opposed to Done or Error). Delete callbacks when a request
is Cancelled.

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Tested-by: Bence Ferdinandy <bence@ferdinandy.com>
Acked-by: Robin Jarry <robin@jarry.cc>
---
 lib/msgstore.go          | 30 +++++++++++++++++++-----------
 widgets/dirlist.go       |  5 ++++-
 worker/types/messages.go | 17 ++++++++++++++---
 worker/types/worker.go   |  3 ++-
 4 files changed, 39 insertions(+), 16 deletions(-)

diff --git a/lib/msgstore.go b/lib/msgstore.go
index f7ffaa51..77aeb4c1 100644
--- a/lib/msgstore.go
+++ b/lib/msgstore.go
@@ -139,16 +139,20 @@ func (store *MessageStore) FetchHeaders(uids []uint32,
 		}
 	}
 	if len(toFetch) > 0 {
-		store.worker.PostAction(&types.FetchMessageHeaders{Uids: toFetch}, func(msg types.WorkerMessage) {
-			if _, ok := msg.(*types.Error); ok {
-				for _, uid := range toFetch {
-					delete(store.pendingHeaders, uid)
+		store.worker.PostAction(&types.FetchMessageHeaders{
+			Context: store.ctx,
+			Uids:    toFetch,
+		},
+			func(msg types.WorkerMessage) {
+				if _, ok := msg.(*types.Error); ok {
+					for _, uid := range toFetch {
+						delete(store.pendingHeaders, uid)
+					}
 				}
-			}
-			if cb != nil {
-				cb(msg)
-			}
-		})
+				if cb != nil {
+					cb(msg)
+				}
+			})
 	}
 }
 
@@ -664,7 +668,8 @@ func (store *MessageStore) Prev() {
 
 func (store *MessageStore) Search(args []string, cb func([]uint32)) {
 	store.worker.PostAction(&types.SearchDirectory{
-		Argv: args,
+		Context: store.ctx,
+		Argv:    args,
 	}, func(msg types.WorkerMessage) {
 		if msg, ok := msg.(*types.SearchResults); ok {
 			allowedUids := store.Uids()
@@ -776,11 +781,13 @@ func (store *MessageStore) Sort(criteria []*types.SortCriterion, cb func(types.W
 
 	if store.threadedView && !store.buildThreads {
 		store.worker.PostAction(&types.FetchDirectoryThreaded{
+			Context:        store.ctx,
 			SortCriteria:   criteria,
 			FilterCriteria: store.filter,
 		}, handle_return)
 	} else {
 		store.worker.PostAction(&types.FetchDirectoryContents{
+			Context:        store.ctx,
 			SortCriteria:   criteria,
 			FilterCriteria: store.filter,
 		}, handle_return)
@@ -830,7 +837,8 @@ func (store *MessageStore) fetchFlags() {
 	store.fetchFlagsDebounce = time.AfterFunc(store.fetchFlagsDelay, func() {
 		store.Lock()
 		store.worker.PostAction(&types.FetchMessageFlags{
-			Uids: store.needsFlags,
+			Context: store.ctx,
+			Uids:    store.needsFlags,
 		}, nil)
 		store.needsFlags = []uint32{}
 		store.Unlock()
diff --git a/widgets/dirlist.go b/widgets/dirlist.go
index 3b5c2d91..788e197f 100644
--- a/widgets/dirlist.go
+++ b/widgets/dirlist.go
@@ -161,7 +161,10 @@ func (dirlist *DirectoryList) Select(name string) {
 
 		select {
 		case <-time.After(delay):
-			dirlist.worker.PostAction(&types.OpenDirectory{Directory: name},
+			dirlist.worker.PostAction(&types.OpenDirectory{
+				Context:   dirlist.ctx,
+				Directory: name,
+			},
 				func(msg types.WorkerMessage) {
 					switch msg.(type) {
 					case *types.Error:
diff --git a/worker/types/messages.go b/worker/types/messages.go
index 0745de5b..7bad31f9 100644
--- a/worker/types/messages.go
+++ b/worker/types/messages.go
@@ -1,6 +1,7 @@
 package types
 
 import (
+	"context"
 	"io"
 	"time"
 
@@ -59,6 +60,10 @@ type Error struct {
 	Error error
 }
 
+type Cancelled struct {
+	Message
+}
+
 type ConnError struct {
 	Message
 	Error error
@@ -93,24 +98,28 @@ type ListDirectories struct {
 
 type OpenDirectory struct {
 	Message
+	Context   context.Context
 	Directory string
 }
 
 type FetchDirectoryContents struct {
 	Message
+	Context        context.Context
 	SortCriteria   []*SortCriterion
 	FilterCriteria []string
 }
 
 type FetchDirectoryThreaded struct {
 	Message
+	Context        context.Context
 	SortCriteria   []*SortCriterion
 	FilterCriteria []string
 }
 
 type SearchDirectory struct {
 	Message
-	Argv []string
+	Context context.Context
+	Argv    []string
 }
 
 type DirectoryThreaded struct {
@@ -132,7 +141,8 @@ type RemoveDirectory struct {
 
 type FetchMessageHeaders struct {
 	Message
-	Uids []uint32
+	Context context.Context
+	Uids    []uint32
 }
 
 type FetchFullMessages struct {
@@ -148,7 +158,8 @@ type FetchMessageBodyPart struct {
 
 type FetchMessageFlags struct {
 	Message
-	Uids []uint32
+	Context context.Context
+	Uids    []uint32
 }
 
 type DeleteMessages struct {
diff --git a/worker/types/worker.go b/worker/types/worker.go
index cc398da4..e263679a 100644
--- a/worker/types/worker.go
+++ b/worker/types/worker.go
@@ -122,7 +122,8 @@ func (worker *Worker) ProcessMessage(msg WorkerMessage) WorkerMessage {
 		worker.Unlock()
 		if ok {
 			f(msg)
-			if _, ok := msg.(*Done); ok {
+			switch msg.(type) {
+			case *Cancelled, *Done:
 				worker.Lock()
 				delete(worker.actionCallbacks, inResponseTo.getId())
 				worker.Unlock()
-- 
cgit