interpreter: Support debug-hooks

Author: hunger

internal/interpreter/api.rs

@@ -1290,6 +1290,12 @@ impl ComponentInstance {
         d.set_property(comp.borrow(), &name, value)
     }
 
+    /// Set a callback triggered by `@debug-hook`-ed properties.
+    #[cfg(feature = "internal-highlight")]
+    pub fn set_debug_hook_callback(&self, observer: Option<crate::debug_hook::DebugHookCallback>) {
+        crate::debug_hook::set_debug_hook_callback(observer);
+    }
+
     /// Set a handler for the callback with the given name. A callback with that
     /// name must be defined in the document otherwise an error will be returned.
     ///

internal/interpreter/debug_hook.rs

@@ -0,0 +1,39 @@
+// Copyright © SixtyFPS GmbH <[email protected]>
+// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0
+
+use crate::{eval::ComponentInstance, Value};
+
+use smol_str::SmolStr;
+
+pub type DebugHookCallback = Box<dyn Fn(&str, usize, &crate::Value) -> Value>;
+
+thread_local! { static DEBUG_HOOK_CALLBACK: std::cell::RefCell<Option<DebugHookCallback>> = Default::default(); }
+
+pub(crate) fn set_debug_hook_callback(func: Option<DebugHookCallback>) {
+    DEBUG_HOOK_CALLBACK.with(|callback| {
+        *callback.borrow_mut() = func;
+    })
+}
+
+fn find_repeat_count(instance: &ComponentInstance) -> usize {
+    // FIXME: Do something to find the component's repeated index.
+    match instance {
+        ComponentInstance::InstanceRef(_) => 0,
+        ComponentInstance::GlobalComponent(_) => 0,
+    }
+}
+
+pub(crate) fn debug_hook_triggered(
+    instance: &ComponentInstance,
+    id: SmolStr,
+    value: Value,
+) -> Value {
+    let repeat_count = find_repeat_count(instance);
+    DEBUG_HOOK_CALLBACK.with(|callback| {
+        if let Some(callback) = &*callback.borrow() {
+            callback(id.as_str(), repeat_count, &value)
+        } else {
+            value
+        }
+    })
+}

internal/interpreter/eval.rs

@@ -396,7 +396,13 @@ pub fn eval_expression(expression: &Expression, local_context: &mut EvalLocalCon
             }
         }
         Expression::EmptyComponentFactory => Value::ComponentFactory(Default::default()),
-        Expression::DebugHook { expression, .. } => eval_expression(expression, local_context),
+        Expression::DebugHook { expression, id: _id } => {
+            let value = eval_expression(expression, local_context);
+            #[cfg(feature = "internal-highlight")]
+            let value = crate::debug_hook::debug_hook_triggered(&local_context.component_instance, _id.clone(), value);
+            value
+
+        }
     }
 }
 

internal/interpreter/lib.rs

@@ -79,6 +79,8 @@ compile_error!(
 );
 
 mod api;
+#[cfg(feature = "internal-highlight")]
+mod debug_hook;
 mod dynamic_item_tree;
 mod dynamic_type;
 mod eval;

tools/lsp/preview.rs

@@ -128,6 +128,7 @@ struct PreviewState {
     preview_loading_delay_timer: Option<slint::Timer>,
     initial_live_data: preview_data::PreviewDataMap,
     current_live_data: preview_data::PreviewDataMap,
+    debug_hook_random_state: std::hash::RandomState,
 }
 
 impl PreviewState {
@@ -1296,6 +1297,7 @@ async fn parse_source(
     source_code: String,
     style: String,
     component: Option<String>,
+    debug_hook_random_state: std::hash::RandomState,
     file_loader_fallback: impl Fn(
             String,
         ) -> core::pin::Pin<
@@ -1331,6 +1333,9 @@ async fn parse_source(
     cc.include_paths = include_paths;
     cc.library_paths = library_paths;
 
+    cc.debug_info = true;
+    cc.debug_hooks = Some(debug_hook_random_state);
+
     let (open_file_fallback, source_file_versions) =
         common::document_cache::document_cache_parts_setup(
             cc,
@@ -1353,7 +1358,12 @@ async fn reload_preview_impl(
 ) -> Result<(), PlatformError> {
     start_parsing();
 
-    if let Some(component_instance) = component_instance() {
+    let (component_instance, debug_hook_random_state) = PREVIEW_STATE.with(|preview_state| {
+        let preview_state = preview_state.borrow();
+        (preview_state.component_instance(), preview_state.debug_hook_random_state.clone())
+    });
+
+    if let Some(component_instance) = component_instance {
         let live_preview_data =
             preview_data::query_preview_data_properties_and_callbacks(&component_instance);
         set_current_live_data(live_preview_data);
@@ -1370,6 +1380,7 @@ async fn reload_preview_impl(
         source,
         style,
         component.component.clone(),
+        debug_hook_random_state,
         move |path| {
             let path = path.to_owned();
             Box::pin(async move {
@@ -1897,6 +1908,7 @@ pub mod test {
 
         let path = main_test_file_name();
         let source_code = code.get(&path).unwrap().clone();
+        let debug_hook_random_state = std::hash::RandomState::default();
         let (diagnostics, component_definition, _, _) = spin_on::spin_on(super::parse_source(
             vec![],
             std::collections::HashMap::new(),
@@ -1905,6 +1917,7 @@ pub mod test {
             source_code.to_string(),
             style.to_string(),
             None,
+            debug_hook_random_state,
             move |path| {
                 let code = code.clone();
                 let path = PathBuf::from(&path);