From 1db9c8b344eb987b38d8de8be224165efdf8bb7a Mon Sep 17 00:00:00 2001
From: Michael Kirk <michael.code@endoftheworl.de>
Date: Thu, 8 Jun 2017 08:11:58 -0400
Subject: [PATCH] prefer archiving vs deleting sessions.

This gives us a little resiliency to handling messages out of order
across key change.

We still *always* print SN when they change.
And we still verify that the session used for encrypt/decrypt is the trusted
session

// FREEBIE
---
 src/Devices/OWSRecordTranscriptJob.m          |  2 +-
 src/Messages/TSMessagesManager.m              |  2 +-
 .../TSStorageManager+SessionStore.h           |  2 ++
 .../TSStorageManager+SessionStore.m           | 30 +++++++++++++++++++
 4 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/src/Devices/OWSRecordTranscriptJob.m b/src/Devices/OWSRecordTranscriptJob.m
index 2a6bcea7b..70e57b819 100644
--- a/src/Devices/OWSRecordTranscriptJob.m
+++ b/src/Devices/OWSRecordTranscriptJob.m
@@ -47,7 +47,7 @@ NS_ASSUME_NONNULL_BEGIN
 
     if (transcript.isEndSessionMessage) {
         DDLogInfo(@"%@ EndSession was sent to recipient: %@.", self.tag, transcript.recipientId);
-        [self.storageManager deleteAllSessionsForContact:transcript.recipientId];
+        [self.storageManager archiveAllSessionsForContact:transcript.recipientId];
         [[[TSInfoMessage alloc] initWithTimestamp:transcript.timestamp
                                          inThread:transcript.thread
                                       messageType:TSInfoMessageTypeSessionDidEnd] save];
diff --git a/src/Messages/TSMessagesManager.m b/src/Messages/TSMessagesManager.m
index e3bdce81b..6249121e7 100644
--- a/src/Messages/TSMessagesManager.m
+++ b/src/Messages/TSMessagesManager.m
@@ -721,7 +721,7 @@ NS_ASSUME_NONNULL_BEGIN
     }];
 
     dispatch_async([OWSDispatch sessionStoreQueue], ^{
-        [[TSStorageManager sharedManager] deleteAllSessionsForContact:endSessionEnvelope.source];
+        [[TSStorageManager sharedManager] archiveAllSessionsForContact:endSessionEnvelope.source];
     });
 }
 
diff --git a/src/Storage/AxolotlStore/TSStorageManager+SessionStore.h b/src/Storage/AxolotlStore/TSStorageManager+SessionStore.h
index b33f33119..741146204 100644
--- a/src/Storage/AxolotlStore/TSStorageManager+SessionStore.h
+++ b/src/Storage/AxolotlStore/TSStorageManager+SessionStore.h
@@ -7,6 +7,8 @@
 
 @interface TSStorageManager (SessionStore) <SessionStore>
 
+- (void)archiveAllSessionsForContact:(NSString *)contactIdentifier;
+
 #pragma mark - debug
 
 - (void)printAllSessions;
diff --git a/src/Storage/AxolotlStore/TSStorageManager+SessionStore.m b/src/Storage/AxolotlStore/TSStorageManager+SessionStore.m
index 74e26fc53..2e6f3690b 100644
--- a/src/Storage/AxolotlStore/TSStorageManager+SessionStore.m
+++ b/src/Storage/AxolotlStore/TSStorageManager+SessionStore.m
@@ -3,6 +3,7 @@
 //
 
 #import "TSStorageManager+SessionStore.h"
+#import <AxolotlKit/SessionRecord.h>
 
 NSString *const TSStorageManagerSessionStoreCollection = @"TSStorageManagerSessionStoreCollection";
 NSString *const kSessionStoreDBConnectionKey = @"kSessionStoreDBConnectionKey";
@@ -158,6 +159,35 @@ void AssertIsOnSessionStoreQueue()
     }];
 }
 
+- (void)archiveAllSessionsForContact:(NSString *)contactIdentifier
+{
+    AssertIsOnSessionStoreQueue();
+
+    DDLogInfo(@"[TSStorageManager (SessionStore)] archiving all sessions for contact: %@", contactIdentifier);
+
+    __block NSDictionary<NSNumber *, SessionRecord *> *sessionRecords;
+    [self.sessionDBConnection readWriteWithBlock:^(YapDatabaseReadWriteTransaction *transaction) {
+        sessionRecords =
+            [transaction objectForKey:contactIdentifier inCollection:TSStorageManagerSessionStoreCollection];
+
+
+        for (id deviceId in sessionRecords) {
+            id object = sessionRecords[deviceId];
+            if (![object isKindOfClass:[SessionRecord class]]) {
+                OWSFail(@"Unexpected object in session dict: %@", object);
+                continue;
+            }
+
+            SessionRecord *sessionRecord = (SessionRecord *)object;
+            [sessionRecord archiveCurrentState];
+        }
+
+        [transaction setObject:sessionRecords
+                        forKey:contactIdentifier
+                  inCollection:TSStorageManagerSessionStoreCollection];
+    }];
+}
+
 #pragma mark - debug
 
 - (void)printAllSessions