constellation: allow event tracing to be configured with RUST_LOG (#31659)

components/constellation/constellation.rs

@@ -1334,7 +1334,7 @@ where
     }
 
     fn handle_request_from_compositor(&mut self, message: FromCompositorMsg) {
-        trace!("Got compositor message: {:?}", message);
+        trace_msg_from_compositor!(message, "{message:?}");
         match message {
             FromCompositorMsg::Exit => {
                 self.handle_exit();
@@ -1552,11 +1552,7 @@ where
 
     fn handle_request_from_script(&mut self, message: (PipelineId, FromScriptMsg)) {
         let (source_pipeline_id, content) = message;
-        trace!(
-            "{}: Message from pipeline: {:?}",
-            source_pipeline_id,
-            content,
-        );
+        trace_script_msg!(content, "{source_pipeline_id}: {content:?}");
 
         let source_top_ctx_id = match self
             .pipelines
@@ -2098,7 +2094,7 @@ where
     }
 
     fn handle_request_from_layout(&mut self, message: FromLayoutMsg) {
-        debug!("Got layout message: {:?}", message);
+        trace_layout_msg!(message, "{message:?}");
         match message {
             // Layout sends new sizes for all subframes. This needs to be reflected by all
             // frame trees in the navigation context containing the subframe.

components/constellation/lib.rs

@@ -4,6 +4,9 @@
 
 #![deny(unsafe_code)]
 
+#[macro_use]
+mod tracing;
+
 mod browsingcontext;
 mod constellation;
 mod event_loop;

components/constellation/tracing.rs

@@ -0,0 +1,261 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+/// Log an event from compositor at trace level.
+/// - To disable tracing: RUST_LOG='constellation<compositor@=off'
+/// - To enable tracing: RUST_LOG='constellation<compositor@'
+/// - Recommended filters when tracing is enabled:
+///   - constellation<compositor@ForwardEvent(MouseMoveEvent)=off
+///   - constellation<compositor@LogEntry=off
+///   - constellation<compositor@ReadyToPresent=off
+macro_rules! trace_msg_from_compositor {
+    // This macro only exists to put the docs in the same file as the target prefix,
+    // so the macro definition is always the same.
+    ($event:expr, $($rest:tt)+) => {
+        ::log::trace!(target: $crate::tracing::LogTarget::log_target(&$event), $($rest)+)
+    };
+}
+
+/// Log an event from script at trace level.
+/// - To disable tracing: RUST_LOG='constellation<script@=off'
+/// - To enable tracing: RUST_LOG='constellation<script@'
+/// - Recommended filters when tracing is enabled:
+///   - constellation<script@LogEntry=off
+macro_rules! trace_script_msg {
+    // This macro only exists to put the docs in the same file as the target prefix,
+    // so the macro definition is always the same.
+    ($event:expr, $($rest:tt)+) => {
+        ::log::trace!(target: $crate::tracing::LogTarget::log_target(&$event), $($rest)+)
+    };
+}
+
+/// Log an event from layout at trace level.
+/// - To disable tracing: RUST_LOG='constellation<layout@=off'
+/// - To enable tracing: RUST_LOG='constellation<layout@'
+macro_rules! trace_layout_msg {
+    // This macro only exists to put the docs in the same file as the target prefix,
+    // so the macro definition is always the same.
+    ($event:expr, $($rest:tt)+) => {
+        ::log::trace!(target: $crate::tracing::LogTarget::log_target(&$event), $($rest)+)
+    };
+}
+
+/// Get the log target for an event, as a static string.
+pub(crate) trait LogTarget {
+    fn log_target(&self) -> &'static str;
+}
+
+mod from_compositor {
+    use super::LogTarget;
+
+    macro_rules! target {
+        ($($name:literal)+) => {
+            concat!("constellation<compositor@", $($name),+)
+        };
+    }
+
+    impl LogTarget for compositing_traits::ConstellationMsg {
+        fn log_target(&self) -> &'static str {
+            match self {
+                Self::Exit => target!("Exit"),
+                Self::GetBrowsingContext(_, _) => target!("GetBrowsingContext"),
+                Self::GetPipeline(_, _) => target!("GetPipeline"),
+                Self::GetFocusTopLevelBrowsingContext(_) => {
+                    target!("GetFocusTopLevelBrowsingContext")
+                },
+                Self::IsReadyToSaveImage(_) => target!("IsReadyToSaveImage"),
+                Self::Keyboard(_) => target!("Keyboard"),
+                Self::AllowNavigationResponse(_, _) => target!("AllowNavigationResponse"),
+                Self::LoadUrl(_, _) => target!("LoadUrl"),
+                Self::ClearCache => target!("ClearCache"),
+                Self::TraverseHistory(_, _) => target!("TraverseHistory"),
+                Self::WindowSize(_, _, _) => target!("WindowSize"),
+                Self::TickAnimation(_, _) => target!("TickAnimation"),
+                Self::WebDriverCommand(_) => target!("WebDriverCommand"),
+                Self::Reload(_) => target!("Reload"),
+                Self::LogEntry(_, _, _) => target!("LogEntry"),
+                Self::NewWebView(_, _) => target!("NewWebView"),
+                Self::CloseWebView(_) => target!("CloseWebView"),
+                Self::SendError(_, _) => target!("SendError"),
+                Self::FocusWebView(_) => target!("FocusWebView"),
+                Self::BlurWebView => target!("BlurWebView"),
+                Self::ForwardEvent(_, event) => event.log_target(),
+                Self::SetCursor(_) => target!("SetCursor"),
+                Self::EnableProfiler(_, _) => target!("EnableProfiler"),
+                Self::DisableProfiler => target!("DisableProfiler"),
+                Self::ExitFullScreen(_) => target!("ExitFullScreen"),
+                Self::MediaSessionAction(_) => target!("MediaSessionAction"),
+                Self::WebViewVisibilityChanged(_, _) => target!("WebViewVisibilityChanged"),
+                Self::IMEDismissed => target!("IMEDismissed"),
+                Self::ReadyToPresent(_) => target!("ReadyToPresent"),
+                Self::Gamepad(_) => target!("Gamepad"),
+            }
+        }
+    }
+
+    impl LogTarget for script_traits::CompositorEvent {
+        fn log_target(&self) -> &'static str {
+            macro_rules! target_variant {
+                ($name:literal) => {
+                    target!("ForwardEvent(" $name ")")
+                };
+            }
+            match self {
+                Self::ResizeEvent(_, _) => target_variant!("ResizeEvent"),
+                Self::MouseButtonEvent(_, _, _, _, _, _) => target_variant!("MouseButtonEvent"),
+                Self::MouseMoveEvent(_, _, _) => target_variant!("MouseMoveEvent"),
+                Self::TouchEvent(_, _, _, _) => target_variant!("TouchEvent"),
+                Self::WheelEvent(_, _, _) => target_variant!("WheelEvent"),
+                Self::KeyboardEvent(_) => target_variant!("KeyboardEvent"),
+                Self::CompositionEvent(_) => target_variant!("CompositionEvent"),
+                Self::IMEDismissedEvent => target_variant!("IMEDismissedEvent"),
+                Self::GamepadEvent(_) => target_variant!("GamepadEvent"),
+            }
+        }
+    }
+}
+
+mod from_script {
+    use super::LogTarget;
+
+    macro_rules! target {
+        ($($name:literal)+) => {
+            concat!("constellation<script@", $($name),+)
+        };
+    }
+
+    impl LogTarget for script_traits::ScriptMsg {
+        fn log_target(&self) -> &'static str {
+            match self {
+                Self::CompleteMessagePortTransfer(_, _) => target!("CompleteMessagePortTransfer"),
+                Self::MessagePortTransferResult(_, _, _) => target!("MessagePortTransferResult"),
+                Self::NewMessagePort(_, _) => target!("NewMessagePort"),
+                Self::NewMessagePortRouter(_, _) => target!("NewMessagePortRouter"),
+                Self::RemoveMessagePortRouter(_) => target!("RemoveMessagePortRouter"),
+                Self::RerouteMessagePort(_, _) => target!("RerouteMessagePort"),
+                Self::MessagePortShipped(_) => target!("MessagePortShipped"),
+                Self::RemoveMessagePort(_) => target!("RemoveMessagePort"),
+                Self::EntanglePorts(_, _) => target!("EntanglePorts"),
+                Self::NewBroadcastChannelRouter(_, _, _) => target!("NewBroadcastChannelRouter"),
+                Self::RemoveBroadcastChannelRouter(_, _) => target!("RemoveBroadcastChannelRouter"),
+                Self::NewBroadcastChannelNameInRouter(_, _, _) => {
+                    target!("NewBroadcastChannelNameInRouter")
+                },
+                Self::RemoveBroadcastChannelNameInRouter(_, _, _) => {
+                    target!("RemoveBroadcastChannelNameInRouter")
+                },
+                Self::ScheduleBroadcast(_, _) => target!("ScheduleBroadcast"),
+                Self::ForwardToEmbedder(msg) => msg.log_target(),
+                Self::InitiateNavigateRequest(_, _) => target!("InitiateNavigateRequest"),
+                Self::BroadcastStorageEvent(_, _, _, _, _) => target!("BroadcastStorageEvent"),
+                Self::ChangeRunningAnimationsState(_) => target!("ChangeRunningAnimationsState"),
+                Self::CreateCanvasPaintThread(_, _) => target!("CreateCanvasPaintThread"),
+                Self::Focus => target!("Focus"),
+                Self::GetTopForBrowsingContext(_, _) => target!("GetTopForBrowsingContext"),
+                Self::GetBrowsingContextInfo(_, _) => target!("GetBrowsingContextInfo"),
+                Self::GetChildBrowsingContextId(_, _, _) => target!("GetChildBrowsingContextId"),
+                Self::LoadComplete => target!("LoadComplete"),
+                Self::LoadUrl(_, _) => target!("LoadUrl"),
+                Self::AbortLoadUrl => target!("AbortLoadUrl"),
+                Self::PostMessage { .. } => target!("PostMessage"),
+                Self::NavigatedToFragment(_, _) => target!("NavigatedToFragment"),
+                Self::TraverseHistory(_) => target!("TraverseHistory"),
+                Self::PushHistoryState(_, _) => target!("PushHistoryState"),
+                Self::ReplaceHistoryState(_, _) => target!("ReplaceHistoryState"),
+                Self::JointSessionHistoryLength(_) => target!("JointSessionHistoryLength"),
+                Self::RemoveIFrame(_, _) => target!("RemoveIFrame"),
+                Self::VisibilityChangeComplete(_) => target!("VisibilityChangeComplete"),
+                Self::ScriptLoadedURLInIFrame(_) => target!("ScriptLoadedURLInIFrame"),
+                Self::ScriptNewIFrame(_) => target!("ScriptNewIFrame"),
+                Self::ScriptNewAuxiliary(_) => target!("ScriptNewAuxiliary"),
+                Self::ActivateDocument => target!("ActivateDocument"),
+                Self::SetDocumentState(_) => target!("SetDocumentState"),
+                Self::SetLayoutEpoch(_, _) => target!("SetLayoutEpoch"),
+                Self::SetFinalUrl(_) => target!("SetFinalUrl"),
+                Self::TouchEventProcessed(_) => target!("TouchEventProcessed"),
+                Self::LogEntry(_, _) => target!("LogEntry"),
+                Self::DiscardDocument => target!("DiscardDocument"),
+                Self::DiscardTopLevelBrowsingContext => target!("DiscardTopLevelBrowsingContext"),
+                Self::PipelineExited => target!("PipelineExited"),
+                Self::ForwardDOMMessage(_, _) => target!("ForwardDOMMessage"),
+                Self::ScheduleJob(_) => target!("ScheduleJob"),
+                Self::GetClientWindow(_) => target!("GetClientWindow"),
+                Self::GetScreenSize(_) => target!("GetScreenSize"),
+                Self::GetScreenAvailSize(_) => target!("GetScreenAvailSize"),
+                Self::MediaSessionEvent(_, _) => target!("MediaSessionEvent"),
+                Self::RequestAdapter(_, _, _) => target!("RequestAdapter"),
+                Self::GetWebGPUChan(_) => target!("GetWebGPUChan"),
+                Self::TitleChanged(_, _) => target!("TitleChanged"),
+            }
+        }
+    }
+
+    impl LogTarget for embedder_traits::EmbedderMsg {
+        fn log_target(&self) -> &'static str {
+            macro_rules! target_variant {
+                ($name:literal) => {
+                    target!("ForwardToEmbedder(" $name ")")
+                };
+            }
+            match self {
+                Self::Status(_) => target_variant!("Status"),
+                Self::ChangePageTitle(_) => target_variant!("ChangePageTitle"),
+                Self::MoveTo(_) => target_variant!("MoveTo"),
+                Self::ResizeTo(_) => target_variant!("ResizeTo"),
+                Self::Prompt(_, _) => target_variant!("Prompt"),
+                Self::ShowContextMenu(_, _, _) => target_variant!("ShowContextMenu"),
+                Self::AllowNavigationRequest(_, _) => target_variant!("AllowNavigationRequest"),
+                Self::AllowOpeningWebView(_) => target_variant!("AllowOpeningWebView"),
+                Self::WebViewOpened(_) => target_variant!("WebViewOpened"),
+                Self::WebViewClosed(_) => target_variant!("WebViewClosed"),
+                Self::WebViewFocused(_) => target_variant!("WebViewFocused"),
+                Self::WebViewBlurred => target_variant!("WebViewBlurred"),
+                Self::AllowUnload(_) => target_variant!("AllowUnload"),
+                Self::Keyboard(_) => target_variant!("Keyboard"),
+                Self::GetClipboardContents(_) => target_variant!("GetClipboardContents"),
+                Self::SetClipboardContents(_) => target_variant!("SetClipboardContents"),
+                Self::SetCursor(_) => target_variant!("SetCursor"),
+                Self::NewFavicon(_) => target_variant!("NewFavicon"),
+                Self::HeadParsed => target_variant!("HeadParsed"),
+                Self::HistoryChanged(_, _) => target_variant!("HistoryChanged"),
+                Self::SetFullscreenState(_) => target_variant!("SetFullscreenState"),
+                Self::LoadStart => target_variant!("LoadStart"),
+                Self::LoadComplete => target_variant!("LoadComplete"),
+                Self::Panic(_, _) => target_variant!("Panic"),
+                Self::GetSelectedBluetoothDevice(_, _) => {
+                    target_variant!("GetSelectedBluetoothDevice")
+                },
+                Self::SelectFiles(_, _, _) => target_variant!("SelectFiles"),
+                Self::PromptPermission(_, _) => target_variant!("PromptPermission"),
+                Self::ShowIME(_, _, _, _) => target_variant!("ShowIME"),
+                Self::HideIME => target_variant!("HideIME"),
+                Self::Shutdown => target_variant!("Shutdown"),
+                Self::ReportProfile(_) => target_variant!("ReportProfile"),
+                Self::MediaSessionEvent(_) => target_variant!("MediaSessionEvent"),
+                Self::OnDevtoolsStarted(_, _) => target_variant!("OnDevtoolsStarted"),
+                Self::ReadyToPresent => target_variant!("ReadyToPresent"),
+                Self::EventDelivered(_) => target_variant!("EventDelivered"),
+            }
+        }
+    }
+}
+
+mod from_layout {
+    use super::LogTarget;
+
+    macro_rules! target {
+        ($($name:literal)+) => {
+            concat!("constellation<layout@", $($name),+)
+        };
+    }
+
+    impl LogTarget for script_traits::LayoutMsg {
+        fn log_target(&self) -> &'static str {
+            match self {
+                Self::IFrameSizes(_) => target!("IFrameSizes"),
+                Self::PendingPaintMetric(_, _) => target!("PendingPaintMetric"),
+            }
+        }
+    }
+}