implement set/get_ui_config() resurrection (#2672)

* Implement set/get_ui_config and use those methods if config string starts with 'ui.'

* use ensure! macro

deltachat-ffi/deltachat.h

@@ -359,6 +359,11 @@ char*           dc_get_blobdir               (const dc_context_t* context);
  *                    to not mess up with non-delivery-reports or read-receipts.
  *                    0=no limit (default).
  *                    Changes affect future messages only.
+ * - `ui.*`         = All keys prefixed by `ui.` can be used by the user-interfaces for system-specific purposes.
+ *                    The prefix should be followed by the system and maybe subsystem,
+ *                    eg. `ui.desktop.foo`, `ui.desktop.linux.bar`, `ui.android.foo`, `ui.dc40.bar`, `ui.bot.simplebot.baz`.
+ *                    These keys go to backups and allow easy per-account settings when using @ref dc_accounts_t,
+ *                    however, are not handled by the core otherwise.
  *
  * If you want to retrieve a value, use dc_get_config().
  *

deltachat-ffi/src/lib.rs

@@ -134,20 +134,30 @@ pub unsafe extern "C" fn dc_set_config(
     }
     let ctx = &*context;
     let key = to_string_lossy(key);
-    match config::Config::from_str(&key) {
-        Ok(key) => block_on(async move {
-            let value = to_opt_string_lossy(value);
-            ctx.set_config(key, value.as_deref())
+    let value = to_opt_string_lossy(value);
+
+    block_on(async move {
+        if key.starts_with("ui.") {
+            ctx.set_ui_config(&key, value.as_deref())
                 .await
                 .with_context(|| format!("Can't set {} to {:?}", key, value))
                 .log_err(ctx, "dc_set_config() failed")
                 .is_ok() as libc::c_int
-        }),
-        Err(_) => {
-            warn!(ctx, "dc_set_config(): invalid key");
-            0
+        } else {
+            match config::Config::from_str(&key) {
+                Ok(key) => ctx
+                    .set_config(key, value.as_deref())
+                    .await
+                    .with_context(|| format!("Can't set {} to {:?}", key, value))
+                    .log_err(ctx, "dc_set_config() failed")
+                    .is_ok() as libc::c_int,
+                Err(_) => {
+                    warn!(ctx, "dc_set_config(): invalid key");
+                    0
+                }
+            }
         }
-    }
+    })
 }
 
 #[no_mangle]
@@ -160,20 +170,33 @@ pub unsafe extern "C" fn dc_get_config(
         return "".strdup();
     }
     let ctx = &*context;
-    match config::Config::from_str(&to_string_lossy(key)) {
-        Ok(key) => block_on(async move {
-            ctx.get_config(key)
+
+    let key = to_string_lossy(key);
+
+    block_on(async move {
+        if key.starts_with("ui.") {
+            ctx.get_ui_config(&key)
                 .await
-                .log_err(ctx, "Can't get config")
+                .log_err(ctx, "Can't get ui-config")
                 .unwrap_or_default()
                 .unwrap_or_default()
                 .strdup()
-        }),
-        Err(_) => {
-            warn!(ctx, "dc_get_config(): invalid key");
-            "".strdup()
+        } else {
+            match config::Config::from_str(&key) {
+                Ok(key) => ctx
+                    .get_config(key)
+                    .await
+                    .log_err(ctx, "Can't get config")
+                    .unwrap_or_default()
+                    .unwrap_or_default()
+                    .strdup(),
+                Err(_) => {
+                    warn!(ctx, "dc_get_config(): invalid key");
+                    "".strdup()
+                }
+            }
         }
-    }
+    })
 }
 
 #[no_mangle]

src/config.rs

@@ -1,6 +1,6 @@
 //! # Key-value configuration management.
 
-use anyhow::Result;
+use anyhow::{ensure, Result};
 use strum::{EnumProperty, IntoEnumIterator};
 use strum_macros::{AsRefStr, Display, EnumIter, EnumProperty, EnumString};
 
@@ -337,6 +337,21 @@ impl Context {
             .await?;
         Ok(())
     }
+
+    /// Sets an ui-specific key-value pair.
+    /// Keys must be prefixed by `ui.`
+    /// and should be followed by the name of the system and maybe subsystem,
+    /// eg. `ui.desktop.linux.foo`, `ui.desktop.macos.bar`, `ui.ios.foobar`.
+    pub async fn set_ui_config(&self, key: &str, value: Option<&str>) -> Result<()> {
+        ensure!(key.starts_with("ui."), "set_ui_config(): prefix missing.");
+        self.sql.set_raw_config(key, value).await
+    }
+
+    /// Gets an ui-specific value set by set_ui_config().
+    pub async fn get_ui_config(&self, key: &str) -> Result<Option<String>> {
+        ensure!(key.starts_with("ui."), "get_ui_config(): prefix missing.");
+        self.sql.get_raw_config(key).await
+    }
 }
 
 /// Returns all available configuration keys concated together.
@@ -389,4 +404,25 @@ mod tests {
         let media_quality = constants::MediaQuality::from_i32(media_quality).unwrap_or_default();
         assert_eq!(media_quality, constants::MediaQuality::Worse);
     }
+
+    #[async_std::test]
+    async fn test_ui_config() -> Result<()> {
+        let t = TestContext::new().await;
+
+        assert_eq!(t.get_ui_config("ui.desktop.linux.systray").await?, None);
+
+        t.set_ui_config("ui.android.screen_security", Some("safe"))
+            .await?;
+        assert_eq!(
+            t.get_ui_config("ui.android.screen_security").await?,
+            Some("safe".to_string())
+        );
+
+        t.set_ui_config("ui.android.screen_security", None).await?;
+        assert_eq!(t.get_ui_config("ui.android.screen_security").await?, None);
+
+        assert!(t.set_ui_config("configured", Some("bar")).await.is_err());
+
+        Ok(())
+    }
 }