Start work on rejoining channel buffers

crates/rpc/proto/zed.proto

@@ -1,6 +1,8 @@
 syntax = "proto3";
 package zed.messages;
 
+// Looking for a number? Search "// Current max"
+
 message PeerId {
     uint32 owner_id = 1;
     uint32 id = 2;
@@ -151,6 +153,8 @@ message Envelope {
         LeaveChannelBuffer leave_channel_buffer = 134;
         AddChannelBufferCollaborator add_channel_buffer_collaborator = 135;
         RemoveChannelBufferCollaborator remove_channel_buffer_collaborator = 136;
+        RejoinChannelBuffers rejoin_channel_buffers = 139;
+        RejoinChannelBuffersResponse rejoin_channel_buffers_response = 140; // Current max
     }
 }
 
@@ -616,6 +620,12 @@ message BufferVersion {
     repeated VectorClockEntry version = 2;
 }
 
+message ChannelBufferVersion {
+    uint64 channel_id = 1;
+    repeated VectorClockEntry version = 2;
+    uint64 epoch = 3;
+}
+
 enum FormatTrigger {
     Save = 0;
     Manual = 1;
@@ -1008,12 +1018,28 @@ message JoinChannelBuffer {
     uint64 channel_id = 1;
 }
 
+message RejoinChannelBuffers {
+    repeated ChannelBufferVersion buffers = 1;
+}
+
+message RejoinChannelBuffersResponse {
+    repeated RejoinedChannelBuffer buffers = 1;
+}
+
 message JoinChannelBufferResponse {
     uint64 buffer_id = 1;
     uint32 replica_id = 2;
     string base_text = 3;
     repeated Operation operations = 4;
     repeated Collaborator collaborators = 5;
+    uint64 epoch = 6;
+}
+
+message RejoinedChannelBuffer {
+    uint64 channel_id = 1;
+    repeated VectorClockEntry version = 2;
+    repeated Operation operations = 3;
+    repeated Collaborator collaborators = 4;
 }
 
 message LeaveChannelBuffer {

crates/rpc/src/proto.rs

@@ -229,6 +229,8 @@ messages!(
     (StartLanguageServer, Foreground),
     (SynchronizeBuffers, Foreground),
     (SynchronizeBuffersResponse, Foreground),
+    (RejoinChannelBuffers, Foreground),
+    (RejoinChannelBuffersResponse, Foreground),
     (Test, Foreground),
     (Unfollow, Foreground),
     (UnshareProject, Foreground),
@@ -319,6 +321,7 @@ request_messages!(
     (SearchProject, SearchProjectResponse),
     (ShareProject, ShareProjectResponse),
     (SynchronizeBuffers, SynchronizeBuffersResponse),
+    (RejoinChannelBuffers, RejoinChannelBuffersResponse),
     (Test, Test),
     (UpdateBuffer, Ack),
     (UpdateParticipantLocation, Ack),