From 9067bf98bdbbdc0474dda5845ebecac3e3fc9f4c Mon Sep 17 00:00:00 2001
From: Damien Elmes <gpg@ankiweb.net>
Date: Wed, 5 Feb 2020 20:23:29 +1000
Subject: [PATCH] handle concurrent modifications and ankiweb terminating early

---
 rslib/src/media/sync.rs | 62 ++++++++++++++++++++++++++++++++---------
 1 file changed, 49 insertions(+), 13 deletions(-)

diff --git a/rslib/src/media/sync.rs b/rslib/src/media/sync.rs
index 2a7017a92..911a23ab5 100644
--- a/rslib/src/media/sync.rs
+++ b/rslib/src/media/sync.rs
@@ -24,8 +24,6 @@ static SYNC_MAX_FILES: usize = 25;
 static SYNC_MAX_BYTES: usize = (2.5 * 1024.0 * 1024.0) as usize;
 static SYNC_SINGLE_FILE_MAX_BYTES: usize = 100 * 1024 * 1024;
 
-// fixme: concurrent modifications during upload step
-
 /// The counts are not cumulative - the progress hook should accumulate them.
 #[derive(Debug)]
 pub enum Progress {
@@ -157,19 +155,40 @@ where
                 break;
             }
 
-            let file_count = pending.iter().filter(|e| e.sha1.is_some()).count();
-
             let zip_data = zip_files(&self.mgr.media_folder, &pending)?;
-            self.send_zip_data(zip_data).await?;
+            let reply = self.send_zip_data(zip_data).await?;
+
+            let (processed_files, processed_deletions): (Vec<_>, Vec<_>) = pending
+                .iter()
+                .take(reply.processed)
+                .partition(|e| e.sha1.is_some());
 
             self.progress(Progress::Uploaded {
-                files: file_count,
-                deletions: pending.len() - file_count,
+                files: processed_files.len(),
+                deletions: processed_deletions.len(),
             })?;
 
-            let fnames: Vec<_> = pending.iter().map(|e| &e.fname).collect();
-            self.ctx
-                .transact(|ctx| record_clean(ctx, fnames.as_slice()))?;
+            let fnames: Vec<_> = processed_files
+                .iter()
+                .chain(processed_deletions.iter())
+                .map(|e| &e.fname)
+                .collect();
+            let fname_cnt = fnames.len() as i32;
+            self.ctx.transact(|ctx| {
+                record_clean(ctx, fnames.as_slice())?;
+                let mut meta = ctx.get_meta()?;
+                if meta.last_sync_usn + fname_cnt == reply.current_usn {
+                    meta.last_sync_usn = reply.current_usn;
+                    ctx.set_meta(&meta)?;
+                } else {
+                    debug!(
+                        "server usn {} is not {}, skipping usn update",
+                        reply.current_usn,
+                        meta.last_sync_usn + fname_cnt
+                    );
+                }
+                Ok(())
+            })?;
         }
 
         Ok(())
@@ -230,12 +249,17 @@ where
         resp.bytes().await.map_err(Into::into)
     }
 
-    async fn send_zip_data(&self, data: Vec<u8>) -> Result<()> {
+    async fn send_zip_data(&self, data: Vec<u8>) -> Result<UploadReply> {
         let url = format!("{}uploadChanges", self.endpoint);
 
-        ankiweb_bytes_request(&self.client, &url, data, self.skey()).await?;
+        let resp = ankiweb_bytes_request(&self.client, &url, data, self.skey()).await?;
+        let res: UploadResult = resp.json().await?;
 
-        Ok(())
+        if let Some(reply) = res.data {
+            Ok(reply)
+        } else {
+            Err(AnkiError::server_message(res.err))
+        }
     }
 }
 
@@ -568,6 +592,18 @@ struct UploadEntry<'a> {
     in_zip_name: Option<String>,
 }
 
+#[derive(Deserialize, Debug)]
+struct UploadResult {
+    data: Option<UploadReply>,
+    err: String,
+}
+
+#[derive(Deserialize, Debug)]
+struct UploadReply {
+    processed: usize,
+    current_usn: i32,
+}
+
 fn zip_files(media_folder: &Path, files: &[MediaEntry]) -> Result<Vec<u8>> {
     let buf = vec![];