Merge pull request #1651 from lightpanda-io/more_pump_message_loop

Run the MessageLoop [a lot] more.

.github/actions/install/action.yml

@@ -13,7 +13,7 @@ inputs:
   zig-v8:
     description: 'zig v8 version to install'
     required: false
-    default: 'v0.3.0'
+    default: 'v0.3.1'
   v8:
     description: 'v8 version to install'
     required: false

Dockerfile

@@ -3,7 +3,7 @@ FROM debian:stable-slim
 ARG MINISIG=0.12
 ARG ZIG_MINISIG=RWSGOq2NVecA2UPNdBUZykf1CCb147pkmdtYxgb3Ti+JO/wCYvhbAb/U
 ARG V8=14.0.365.4
-ARG ZIG_V8=v0.3.0
+ARG ZIG_V8=v0.3.1
 ARG TARGETPLATFORM
 
 RUN apt-get update -yq && \

build.zig.zon

@@ -6,8 +6,9 @@
     .minimum_zig_version = "0.15.2",
     .dependencies = .{
         .v8 = .{
-            .url = "https://github.com/lightpanda-io/zig-v8-fork/archive/refs/tags/v0.3.0.tar.gz",
-            .hash = "v8-0.0.0-xddH69R6BADRXsnhjA8wNnfKfLQACF1I7CSTZvsMAvp8",
+            .url = "https://github.com/lightpanda-io/zig-v8-fork/archive/refs/tags/v0.3.1.tar.gz",
+            .hash = "v8-0.0.0-xddH64J7BAC81mkf6G9RbEJxS-W3TIRl5iFnShwbqCqy",
+
         },
         //.v8 = .{ .path = "../zig-v8-fork" },
         .@"boringssl-zig" = .{

src/browser/Browser.zig

@@ -92,10 +92,24 @@ pub fn runMicrotasks(self: *Browser) void {
 }
 
 pub fn runMacrotasks(self: *Browser) !?u64 {
-    return try self.env.runMacrotasks();
+    const env = &self.env;
+
+    const time_to_next = try self.env.runMacrotasks();
+    env.pumpMessageLoop();
+
+    // either of the above could have queued more microtasks
+    env.runMicrotasks();
+
+    return time_to_next;
 }
 
-pub fn runMessageLoop(self: *const Browser) void {
-    self.env.pumpMessageLoop();
+pub fn hasBackgroundTasks(self: *Browser) bool {
+    return self.env.hasBackgroundTasks();
+}
+pub fn waitForBackgroundTasks(self: *Browser) void {
+    self.env.waitForBackgroundTasks();
+}
+
+pub fn runIdleTasks(self: *const Browser) void {
     self.env.runIdleTasks();
 }

src/browser/Page.zig

@@ -314,12 +314,12 @@ pub fn init(self: *Page, id: u32, session: *Session, parent: ?*Page) !void {
     if (comptime builtin.is_test == false) {
         // HTML test runner manually calls these as necessary
         try self.js.scheduler.add(session.browser, struct {
-            fn runMessageLoop(ctx: *anyopaque) !?u32 {
+            fn runIdleTasks(ctx: *anyopaque) !?u32 {
                 const b: *@import("Browser.zig") = @ptrCast(@alignCast(ctx));
-                b.runMessageLoop();
-                return 250;
+                b.runIdleTasks();
+                return 200;
             }
-        }.runMessageLoop, 250, .{ .name = "page.messageLoop" });
+        }.runIdleTasks, 200, .{ .name = "page.runIdleTasks", .low_priority = true });
     }
 }
 

src/browser/ScriptManager.zig

@@ -873,8 +873,7 @@ pub const Script = struct {
         }
 
         defer {
-            // We should run microtasks even if script execution fails.
-            local.runMicrotasks();
+            local.runMacrotasks(); // also runs microtasks
             _ = page.js.scheduler.run() catch |err| {
                 log.err(.page, "scheduler", .{ .err = err });
             };

src/browser/Session.zig

@@ -258,7 +258,7 @@ fn _wait(self: *Session, page: *Page, wait_ms: u32) !WaitResult {
                         std.debug.assert(http_client.intercepted == 0);
                     }
 
-                    const ms = ms_to_next_task orelse blk: {
+                    const ms: u64 = ms_to_next_task orelse blk: {
                         if (wait_ms - ms_remaining < 100) {
                             if (comptime builtin.is_test) {
                                 return .done;
@@ -268,6 +268,14 @@ fn _wait(self: *Session, page: *Page, wait_ms: u32) !WaitResult {
                             // background jobs.
                             break :blk 50;
                         }
+
+                        if (browser.hasBackgroundTasks()) {
+                            // _we_ have nothing to run, but v8 is working on
+                            // background tasks. We'll wait for them.
+                            browser.waitForBackgroundTasks();
+                            break :blk 20;
+                        }
+
                         // No http transfers, no cdp extra socket, no
                         // scheduled tasks, we're done.
                         return .done;
@@ -293,8 +301,14 @@ fn _wait(self: *Session, page: *Page, wait_ms: u32) !WaitResult {
                     // an cdp_socket registered with the http client).
                     // We should continue to run lowPriority tasks, so we
                     // minimize how long we'll poll for network I/O.
-                    const ms_to_wait = @min(200, @min(ms_remaining, ms_to_next_task orelse 200));
-                    if (try http_client.tick(ms_to_wait) == .cdp_socket) {
+                    var ms_to_wait = @min(200, ms_to_next_task orelse 200);
+                    if (ms_to_wait > 10 and browser.hasBackgroundTasks()) {
+                        // if we have background tasks, we don't want to wait too
+                        // long for a message from the client. We want to go back
+                        // to the top of the loop and run macrotasks.
+                        ms_to_wait = 10;
+                    }
+                    if (try http_client.tick(@min(ms_remaining, ms_to_wait)) == .cdp_socket) {
                         // data on a socket we aren't handling, return to caller
                         return .cdp_socket;
                     }

src/browser/js/Context.zig

@@ -237,7 +237,7 @@ pub fn deinit(self: *Context) void {
     env.isolate.notifyContextDisposed();
     // There can be other tasks associated with this context that we need to
     // purge while the context is still alive.
-    env.pumpMessageLoop();
+    _ = env.pumpMessageLoop();
     v8.v8__MicrotaskQueue__DELETE(self.microtask_queue);
 }
 

src/browser/js/Env.zig

@@ -397,10 +397,23 @@ pub fn pumpMessageLoop(self: *const Env) void {
 
     const isolate = self.isolate.handle;
     const platform = self.platform.handle;
-    while (v8.v8__Platform__PumpMessageLoop(platform, isolate, false)) {
-        if (comptime IS_DEBUG) {
-            log.debug(.browser, "pumpMessageLoop", .{});
-        }
+    while (v8.v8__Platform__PumpMessageLoop(platform, isolate, false)) {}
+}
+
+pub fn hasBackgroundTasks(self: *const Env) bool {
+    return v8.v8__Isolate__HasPendingBackgroundTasks(self.isolate.handle);
+}
+
+pub fn waitForBackgroundTasks(self: *Env) void {
+    var hs: v8.HandleScope = undefined;
+    v8.v8__HandleScope__CONSTRUCT(&hs, self.isolate.handle);
+    defer v8.v8__HandleScope__DESTRUCT(&hs);
+
+    const isolate = self.isolate.handle;
+    const platform = self.platform.handle;
+    while (v8.v8__Isolate__HasPendingBackgroundTasks(isolate)) {
+        _ = v8.v8__Platform__PumpMessageLoop(platform, isolate, true);
+        self.runMicrotasks();
     }
 }
 

src/browser/js/Local.zig

@@ -82,6 +82,12 @@ pub fn createTypedArray(self: *const Local, comptime array_type: js.ArrayType, s
     return .init(self, size);
 }
 
+pub fn runMacrotasks(self: *const Local) void {
+    const env = self.ctx.env;
+    env.pumpMessageLoop();
+    env.runMicrotasks(); // macrotasks can cause microtasks to queue
+}
+
 pub fn runMicrotasks(self: *const Local) void {
     self.ctx.env.runMicrotasks();
 }

src/cdp/cdp.zig

@@ -436,17 +436,18 @@ pub fn BrowserContext(comptime CDP_T: type) type {
 
         pub fn deinit(self: *Self) void {
             const browser = &self.cdp.browser;
+            const env = &browser.env;
 
             // Drain microtasks makes sure we don't have inspector's callback
             // in progress before deinit.
-            browser.env.runMicrotasks();
+            env.runMicrotasks();
 
             // resetContextGroup detach the inspector from all contexts.
             // It append async tasks, so we make sure we run the message loop
             // before deinit it.
-            browser.env.inspector.?.resetContextGroup();
-            browser.runMessageLoop();
-            browser.env.inspector.?.stopSession();
+            env.inspector.?.resetContextGroup();
+            _ = env.pumpMessageLoop();
+            env.inspector.?.stopSession();
 
             // abort all intercepted requests before closing the sesion/page
             // since some of these might callback into the page/scriptmanager