MXStore: Add a method to remove all the messages sent before a specific timestamp in a room.

CHANGES.rst

@@ -2,6 +2,7 @@ Changes in Matrix iOS SDK in 0.16.6 (2020-05-xx)
 ================================================
 
 Improvements:
+ * MXStore: Add a method to remove all the messages sent before a specific timestamp in a room.
  * MXCrypto: Only create one olm session at a time per device (vector-im/riot-ios/issues/2331).
  * MXCrossSigning: Add the bootstrapWithAuthParams method.
  * MXRecoveryService: Create this service to manage keys we want to store in SSSS.

MatrixSDK/Data/Store/MXFileStore/MXFileStore.m

@@ -319,6 +319,18 @@ - (void)replaceEvent:(MXEvent*)event inRoom:(NSString*)roomId
     }
 }
 
+- (BOOL)removeAllMessagesSentBefore:(uint64_t)limitTs inRoom:(nonnull NSString *)roomId
+{
+    BOOL ret = [super removeAllMessagesSentBefore:limitTs inRoom:roomId];
+
+    if (ret && NSNotFound == [roomsToCommitForMessages indexOfObject:roomId])
+    {
+        [roomsToCommitForMessages addObject:roomId];
+    }
+
+    return ret;
+}
+
 - (void)deleteAllMessagesInRoom:(NSString *)roomId
 {
     [super deleteAllMessagesInRoom:roomId];

MatrixSDK/Data/Store/MXMemoryStore/MXMemoryRoomStore.h

@@ -51,6 +51,16 @@
  */
 - (void)replaceEvent:(MXEvent*)event;
 
+/**
+ Remove all the messages sent before a specific timestamp in a room.
+ The state events are not removed during this operation. We keep them in the timeline.
+
+ @param limitTs the timestamp from which the messages are kept.
+
+ @return YES if at least one event has been removed.
+ */
+- (BOOL)removeAllMessagesSentBefore:(uint64_t)limitTs;
+
 /**
  Get an event from this room.
 

MatrixSDK/Data/Store/MXMemoryStore/MXMemoryRoomStore.m

@@ -76,6 +76,33 @@ - (void)replaceEvent:(MXEvent*)event
     }
 }
 
+- (BOOL)removeAllMessagesSentBefore:(uint64_t)limitTs
+{
+    NSUInteger index = 0;
+    BOOL didChange = NO;
+    while (index < messages.count)
+    {
+        MXEvent *anEvent = messages[index];
+        if (anEvent.isState)
+        {
+            // Keep state event
+            index++;
+        }
+        else if (anEvent.originServerTs < limitTs)
+        {
+            [messages removeObjectAtIndex:index];
+            [messagesByEventIds removeObjectForKey:anEvent.eventId];
+            didChange = YES;
+        }
+        else
+        {
+            // Break the loop, we've reached the first non-state event in the timeline which is not expired
+            break;
+        }
+    }
+    return didChange;
+}
+
 - (MXEvent *)eventWithEventId:(NSString *)eventId
 {
     return messagesByEventIds[eventId];

MatrixSDK/Data/Store/MXMemoryStore/MXMemoryStore.m

@@ -68,6 +68,12 @@ - (void)replaceEvent:(MXEvent *)event inRoom:(NSString *)roomId
     [roomStore replaceEvent:event];
 }
 
+- (BOOL)removeAllMessagesSentBefore:(uint64_t)limitTs inRoom:(nonnull NSString *)roomId
+{
+    MXMemoryRoomStore *roomStore = [self getOrCreateRoomStore:roomId];
+    return [roomStore removeAllMessagesSentBefore:limitTs];
+}
+
 - (BOOL)eventExistsWithEventId:(NSString *)eventId inRoom:(NSString *)roomId
 {
     return (nil != [self eventWithEventId:eventId inRoom:roomId]);

MatrixSDK/Data/Store/MXNoStore/MXNoStore.m

@@ -105,6 +105,17 @@ - (void)replaceEvent:(MXEvent *)event inRoom:(NSString *)roomId
     }
 }
 
+- (BOOL)removeAllMessagesSentBefore:(uint64_t)limitTs inRoom:(nonnull NSString *)roomId
+{
+    // Only the last message is stored
+    MXEvent *lastMessage = lastMessages[roomId];
+    if (!lastMessage.isState && lastMessage.originServerTs < limitTs) {
+        lastMessages[roomId] = nil;
+        return YES;
+    }
+    return NO;
+}
+
 - (BOOL)eventExistsWithEventId:(NSString *)eventId inRoom:(NSString *)roomId
 {
     // Events are not stored. So, we cannot find it.

MatrixSDK/Data/Store/MXStore.h

@@ -70,6 +70,18 @@
  */
 - (void)replaceEvent:(nonnull MXEvent*)event inRoom:(nonnull NSString*)roomId;
 
+/**
+ Remove all the messages sent before a specific timestamp in a room.
+ The state events are not removed during this operation. We keep them in the timeline.
+ This operation doesn't change the pagination token, and the flag indicating that the SDK has reached the end of pagination.
+
+ @param limitTs the timestamp from which the messages are kept.
+ @param roomId the id of the room.
+
+ @return YES if at least one event has been removed.
+ */
+- (BOOL)removeAllMessagesSentBefore:(uint64_t)limitTs inRoom:(nonnull NSString *)roomId;
+
 /**
  Returns a Boolean value that indicates whether an event is already stored.