Add dependencies/vendor (whatsapp)

vendor/go.mau.fi/whatsmeow/appstate/keys.go

@@ -0,0 +1,85 @@
+// Copyright (c) 2021 Tulir Asokan
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// Package appstate implements encoding and decoding WhatsApp's app state patches.
+package appstate
+
+import (
+	"encoding/base64"
+	"sync"
+
+	"go.mau.fi/whatsmeow/store"
+	"go.mau.fi/whatsmeow/util/hkdfutil"
+	waLog "go.mau.fi/whatsmeow/util/log"
+)
+
+// WAPatchName represents a type of app state patch.
+type WAPatchName string
+
+const (
+	// WAPatchCriticalBlock contains the user's settings like push name and locale.
+	WAPatchCriticalBlock WAPatchName = "critical_block"
+	// WAPatchCriticalUnblockLow contains the user's contact list.
+	WAPatchCriticalUnblockLow WAPatchName = "critical_unblock_low"
+	// WAPatchRegularLow contains some local chat settings like pin, archive status, and the setting of whether to unarchive chats when messages come in.
+	WAPatchRegularLow WAPatchName = "regular_low"
+	// WAPatchRegularHigh contains more local chat settings like mute status and starred messages.
+	WAPatchRegularHigh WAPatchName = "regular_high"
+	// WAPatchRegular contains protocol info about app state patches like key expiration.
+	WAPatchRegular WAPatchName = "regular"
+)
+
+// AllPatchNames contains all currently known patch state names.
+var AllPatchNames = [...]WAPatchName{WAPatchCriticalBlock, WAPatchCriticalUnblockLow, WAPatchRegularHigh, WAPatchRegular, WAPatchRegularLow}
+
+type Processor struct {
+	keyCache     map[string]ExpandedAppStateKeys
+	keyCacheLock sync.Mutex
+	Store        *store.Device
+	Log          waLog.Logger
+}
+
+func NewProcessor(store *store.Device, log waLog.Logger) *Processor {
+	return &Processor{
+		keyCache: make(map[string]ExpandedAppStateKeys),
+		Store:    store,
+		Log:      log,
+	}
+}
+
+type ExpandedAppStateKeys struct {
+	Index           []byte
+	ValueEncryption []byte
+	ValueMAC        []byte
+	SnapshotMAC     []byte
+	PatchMAC        []byte
+}
+
+func expandAppStateKeys(keyData []byte) (keys ExpandedAppStateKeys) {
+	appStateKeyExpanded := hkdfutil.SHA256(keyData, nil, []byte("WhatsApp Mutation Keys"), 160)
+	return ExpandedAppStateKeys{appStateKeyExpanded[0:32], appStateKeyExpanded[32:64], appStateKeyExpanded[64:96], appStateKeyExpanded[96:128], appStateKeyExpanded[128:160]}
+}
+
+func (proc *Processor) getAppStateKey(keyID []byte) (keys ExpandedAppStateKeys, err error) {
+	keyCacheID := base64.RawStdEncoding.EncodeToString(keyID)
+	var ok bool
+
+	proc.keyCacheLock.Lock()
+	defer proc.keyCacheLock.Unlock()
+
+	keys, ok = proc.keyCache[keyCacheID]
+	if !ok {
+		var keyData *store.AppStateSyncKey
+		keyData, err = proc.Store.AppStateKeys.GetAppStateSyncKey(keyID)
+		if keyData != nil {
+			keys = expandAppStateKeys(keyData.Data)
+			proc.keyCache[keyCacheID] = keys
+		} else if err == nil {
+			err = ErrKeyNotFound
+		}
+	}
+	return
+}