PeterCxy
/
sfrs
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

api: rewrite some comments on synchronization algorithm

This commit is contained in:
Peter Cai 2020-02-21 21:32:23 +08:00
parent 0277d2c122
commit 908c62b0a1
No known key found for this signature in database
GPG Key ID: 71F5FB4E4F3FD54F
1 changed files with 13 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
src/api.rs
View File

@ -225,14 +225,11 @@ fn items_sync(db: DbConn, u: user::User, params: Json<SyncParams>) -> Custom<Jso
},
Ok(items) => {
if !items.is_empty() {
// If we fetched something
// we should record the current last id to *some* token
// this may be `cursor_token` or `sync_token`
// if we have more to fetch, we set `cursor_token` to this id
// so that the client knows to continue
// and we set `sync_token` to this id regardless, for the
// client to remember where we were even if
// it doesn't need to continue
// If we fetched something, and the length is right at limit
// we may have more to fetch. In this case, we need to
// inform the client to continue fetching, until there is
// nothing more to fetch
// (i.e. until cursor_token is equal to sync_token)
let next_from = items.last().unwrap().id;
if let Some(limit) = inner_params.limit {
if items.len() as i64 == limit {
@ -265,6 +262,10 @@ fn items_sync(db: DbConn, u: user::User, params: Json<SyncParams>) -> Custom<Jso
let mut last_id: i64 = -1;
for mut it in inner_params.items.into_iter() {
// Handle conflicts
// Anything that we just retrieved but need to save immediately
// is potentially a conflict
// TODO: how do we handle this when the sync needs multiple requests
// to finish?
let mut conflicted = false;
for y in resp.retrieved_items.iter() {
if it.uuid == y.uuid {
@ -310,6 +311,10 @@ fn items_sync(db: DbConn, u: user::User, params: Json<SyncParams>) -> Custom<Jso
if last_id > -1 {
// Update sync_token to the latest one of our saved items
// This is ALWAYS the case. `sync_token` indicates the
// LATEST known state of the system by the client,
// but it MAY still need to fill in a bit of history
// (that's where `cursor_token` comes into play)
resp.sync_token = Some(last_id.to_string());
}