api: add dc_replace_webxdc()

deltachat-ffi/deltachat.h

@@ -1175,6 +1175,24 @@ int dc_send_webxdc_status_update (dc_context_t* context, uint32_t msg_id, const
  */
 char* dc_get_webxdc_status_updates (dc_context_t* context, uint32_t msg_id, uint32_t serial);
 
+
+/**
+ * Replaces webxdc app with a new version.
+ *
+ * On the JavaScript side this API could be used like this:
+ * ```
+ * window.webxdc.replaceWebxdc(blob);
+ * ```
+ *
+ * @memberof dc_context_t
+ * @param context The context object.
+ * @param msg_id The ID of the WebXDC message to be replaced.
+ * @param blob New blob to replace WebXDC with.
+ * @param n Blob size.
+ */
+void dc_replace_webxdc(dc_context_t* context, uint32_t msg_id, uint8_t *blob, size_t n);
+
+
 /**
  * Save a draft for a chat in the database.
  *

deltachat-ffi/src/lib.rs

@@ -36,7 +36,7 @@ use deltachat::qr_code_generator::{generate_backup_qr, get_securejoin_qr_svg};
 use deltachat::reaction::{get_msg_reactions, send_reaction, Reactions};
 use deltachat::stock_str::StockMessage;
 use deltachat::stock_str::StockStrings;
-use deltachat::webxdc::StatusUpdateSerial;
+use deltachat::webxdc::{replace_webxdc, StatusUpdateSerial};
 use deltachat::*;
 use deltachat::{accounts::Accounts, log::LogExt};
 use num_traits::{FromPrimitive, ToPrimitive};
@@ -1097,6 +1097,32 @@ pub unsafe extern "C" fn dc_get_webxdc_status_updates(
     .strdup()
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn dc_replace_webxdc(
+    context: *mut dc_context_t,
+    msg_id: u32,
+    blob: *const u8,
+    n: libc::size_t,
+) {
+    if context.is_null() {
+        eprintln!("ignoring careless call to dc_replace_webxdc()");
+        return;
+    }
+
+    let msg_id = MsgId::new(msg_id);
+    let blob_slice = std::slice::from_raw_parts(blob, n);
+
+    let ctx = &*context;
+
+    block_on(async move {
+        replace_webxdc(ctx, msg_id, blob_slice)
+            .await
+            .context("Failed to replace WebXDC")
+            .log_err(ctx)
+            .ok();
+    })
+}
+
 #[no_mangle]
 pub unsafe extern "C" fn dc_set_draft(
     context: *mut dc_context_t,
@@ -1539,14 +1565,10 @@ pub unsafe extern "C" fn dc_delete_chat(context: *mut dc_context_t, chat_id: u32
     }
     let ctx = &*context;
 
-    block_on(async move {
-        ChatId::new(chat_id)
-            .delete(ctx)
-            .await
-            .context("Failed chat delete")
-            .log_err(ctx)
-            .ok();
-    })
+    block_on(ChatId::new(chat_id).delete(ctx))
+        .context("Failed chat delete")
+        .log_err(ctx)
+        .ok();
 }
 
 #[no_mangle]

src/webxdc.rs

@@ -26,6 +26,7 @@ use serde::{Deserialize, Serialize};
 use serde_json::Value;
 use tokio::io::AsyncReadExt;
 
+use crate::blob::BlobObject;
 use crate::chat::Chat;
 use crate::constants::Chattype;
 use crate::contact::ContactId;
@@ -845,6 +846,35 @@ impl Message {
     }
 }
 
+/// Replaces WebXDC blob of existing message.
+///
+/// This API is supposed to be called from within a WebXDC to replace itself
+/// e.g. with an updated or persistently reconfigured version.
+pub async fn replace_webxdc(context: &Context, msg_id: MsgId, data: &[u8]) -> Result<()> {
+    let mut msg = Message::load_from_db(context, msg_id).await?;
+
+    ensure!(
+        msg.get_viewtype() == Viewtype::Webxdc,
+        "Message {msg_id} is not a WebXDC instance"
+    );
+
+    let blob = BlobObject::create(
+        context,
+        &msg.get_filename()
+            .context("Cannot get filename of exising WebXDC instance")?,
+        data,
+    )
+    .await
+    .context("Failed to create WebXDC replacement blob")?;
+
+    let mut param = msg.param.clone();
+    param.set(Param::File, blob.as_name());
+    msg.param = param;
+    msg.update_param(context).await?;
+
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use serde_json::json;
@@ -2623,4 +2653,62 @@ sth_for_the = "future""#
 
         Ok(())
     }
+
+    /// Tests replacing WebXDC with a newer version.
+    ///
+    /// Updates should be preserved after upgrading.
+    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+    async fn test_replace_webxdc() -> Result<()> {
+        let alice = TestContext::new_alice().await;
+        let bob = TestContext::new_bob().await;
+
+        // Alice sends WebXDC instance.
+        let alice_chat = alice.create_chat(&bob).await;
+        let mut alice_instance = create_webxdc_instance(
+            &alice,
+            "minimal.xdc",
+            include_bytes!("../test-data/webxdc/minimal.xdc"),
+        )
+        .await?;
+        alice_instance.set_text("user added text".to_string());
+        send_msg(&alice, alice_chat.id, &mut alice_instance).await?;
+        let alice_instance = alice.get_last_msg().await;
+        assert_eq!(alice_instance.get_text(), "user added text");
+
+        // Bob receives that instance.
+        let alice_sent_instance = alice.pop_sent_msg().await;
+        let bob_received_instance = bob.recv_msg(&alice_sent_instance).await;
+        assert_eq!(bob_received_instance.get_text(), "user added text");
+
+        // Alice sends WebXDC update.
+        alice
+            .send_webxdc_status_update(alice_instance.id, r#"{"payload": 1}"#, "Alice update")
+            .await?;
+        alice.flush_status_updates().await?;
+        let alice_sent_update = alice.pop_sent_msg().await;
+        bob.recv_msg(&alice_sent_update).await;
+        assert_eq!(
+            bob.get_webxdc_status_updates(bob_received_instance.id, StatusUpdateSerial(0))
+                .await?,
+            r#"[{"payload":1,"serial":1,"max_serial":1}]"#
+        );
+
+        // Bob replaces WebXDC.
+        replace_webxdc(
+            &bob,
+            bob_received_instance.id,
+            include_bytes!("../test-data/webxdc/with-minimal-manifest.xdc"),
+        )
+        .await
+        .context("Failed to replace WebXDC")?;
+
+        // Updates are not modified.
+        assert_eq!(
+            bob.get_webxdc_status_updates(bob_received_instance.id, StatusUpdateSerial(0))
+                .await?,
+            r#"[{"payload":1,"serial":1,"max_serial":1}]"#
+        );
+
+        Ok(())
+    }
 }