jmap: fix crash when opening multiple instances

Fix the following error when opening another aerc instance with the same
jmap account:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0x9a1ffd]

git.sr.ht/~rjarry/aerc/worker/jmap/cache.(*JMAPCache).get(0x99d08e?, {0xbc3c1a?, 0xc00003a160?})
	git.sr.ht/~rjarry/aerc/worker/jmap/cache/cache.go:47 +0x1d
git.sr.ht/~rjarry/aerc/worker/jmap/cache.(*JMAPCache).GetSession(0xc00052a030?)
	git.sr.ht/~rjarry/aerc/worker/jmap/cache/session.go:8 +0x29
git.sr.ht/~rjarry/aerc/worker/jmap.(*JMAPWorker).handleConnect(0xc00055e180, 0x0?)
	git.sr.ht/~rjarry/aerc/worker/jmap/connect.go:29 +0xd3
git.sr.ht/~rjarry/aerc/worker/jmap.(*JMAPWorker).handleMessage(0xc000311500?, {0xcc8b00?, 0xc0001fcff0?})
	git.sr.ht/~rjarry/aerc/worker/jmap/worker.go:114 +0x9f
git.sr.ht/~rjarry/aerc/worker/jmap.(*JMAPWorker).Run(0xc00055e180)
	git.sr.ht/~rjarry/aerc/worker/jmap/worker.go:177 +0x10c
git.sr.ht/~rjarry/aerc/widgets.NewAccountView.func3()
	git.sr.ht/~rjarry/aerc/widgets/account.go:110 +0x65
created by git.sr.ht/~rjarry/aerc/widgets.NewAccountView
	git.sr.ht/~rjarry/aerc/widgets/account.go:103 +0x518

Do not return an error if the leveldb cannot be opened, log a message
and fallback on the in-memory cache.

Fixes: be0bfc1ae28b ("worker: add jmap support")
Reported-by: Tim Culverhouse <tim@timculverhouse.com>
Signed-off-by: Robin Jarry <robin@jarry.cc>
Tested-by: Tim Culverhouse <tim@timculverhouse.com>

2 files changed, 15 insertions, 16 deletions

diff --git a/worker/jmap/cache/cache.go b/worker/jmap/cache/cache.go
index ab264744..07d23493 100644
--- a/worker/jmap/cache/cache.go
+++ b/worker/jmap/cache/cache.go
@@ -5,6 +5,7 @@ import (
 	"os"
 	"path"
 
+	"git.sr.ht/~rjarry/aerc/log"
 	"github.com/mitchellh/go-homedir"
 	"github.com/syndtr/goleveldb/leveldb"
 )
@@ -15,29 +16,31 @@ type JMAPCache struct {
 	blobsDir string
 }
 
-func NewJMAPCache(state, blobs bool, accountName string) (*JMAPCache, error) {
+func NewJMAPCache(state, blobs bool, accountName string) *JMAPCache {
 	c := new(JMAPCache)
 	cacheDir, err := os.UserCacheDir()
 	if err != nil {
 		cacheDir, err = homedir.Expand("~/.cache")
 		if err != nil {
-			return nil, err
+			log.Errorf("homedir.Expand: %s", err)
+			cacheDir = ""
 		}
 	}
-	if state {
+	if state && cacheDir != "" {
 		dir := path.Join(cacheDir, "aerc", accountName, "state")
 		_ = os.MkdirAll(dir, 0o700)
 		c.file, err = leveldb.OpenFile(dir, nil)
 		if err != nil {
-			return nil, err
+			log.Errorf("failed to open goleveldb: %s", err)
+			c.mem = make(map[string][]byte)
 		}
 	} else {
 		c.mem = make(map[string][]byte)
 	}
-	if blobs {
+	if blobs && cacheDir != "" {
 		c.blobsDir = path.Join(cacheDir, "aerc", accountName, "blobs")
 	}
-	return c, nil
+	return c
 }
 
 var notfound = errors.New("key not found")
diff --git a/worker/jmap/configure.go b/worker/jmap/configure.go
index f57dbd73..dd6f3f36 100644
--- a/worker/jmap/configure.go
+++ b/worker/jmap/configure.go
@@ -11,6 +11,12 @@ import (
 )
 
 func (w *JMAPWorker) handleConfigure(msg *types.Configure) error {
+	w.config.cacheState = parseBool(msg.Config.Params["cache-state"])
+	w.config.cacheBlobs = parseBool(msg.Config.Params["cache-blobs"])
+	w.config.useLabels = parseBool(msg.Config.Params["use-labels"])
+	w.cache = cache.NewJMAPCache(
+		w.config.cacheState, w.config.cacheBlobs, msg.Config.Name)
+
 	u, err := url.Parse(msg.Config.Source)
 	if err != nil {
 		return err
@@ -36,9 +42,6 @@ func (w *JMAPWorker) handleConfigure(msg *types.Configure) error {
 
 	w.config.endpoint = u.String()
 	w.config.account = msg.Config
-	w.config.cacheState = parseBool(msg.Config.Params["cache-state"])
-	w.config.cacheBlobs = parseBool(msg.Config.Params["cache-blobs"])
-	w.config.useLabels = parseBool(msg.Config.Params["use-labels"])
 	w.config.allMail = msg.Config.Params["all-mail"]
 	if w.config.allMail == "" {
 		w.config.allMail = "All mail"
@@ -51,13 +54,6 @@ func (w *JMAPWorker) handleConfigure(msg *types.Configure) error {
 		w.config.serverPing = dur
 	}
 
-	c, err := cache.NewJMAPCache(
-		w.config.cacheState, w.config.cacheBlobs, msg.Config.Name)
-	if err != nil {
-		return err
-	}
-	w.cache = c
-
 	return nil
 }